CN114534706B - Method for preparing titanium-silicon carrier by recycling waste denitration catalyst - Google Patents

Abstract

The invention relates to a method for preparing a titanium-silicon carrier by recovering a waste denitration catalyst, belonging to the field of flue gas denitrification and material recycling, including pretreatment, alkali leaching, and filtration to obtain filtrate and filter residue, and further filtrate precipitation of vanadium, precipitation of tungsten, and drying to obtain tungsten Calcium acid products, filter residue acid grinding, washing, drying to obtain titanium silicon carrier, and acid and alkali solution neutralization and removal of impurities and reuse. A method for preparing a titanium-silicon carrier by recovering a waste denitrification catalyst provided by the present invention obtains a titanium-silicon carrier by controlling the reaction process and suppressing the reaction of SiO ₂ and TiO ₂ with an alkali, avoiding a complicated silicon removal process, and obtaining a titanium-silicon carrier by controlling the reaction process through CaO or Ca(OH ) ₂ Precipitation and recovery of vanadium and tungsten components, avoiding the high-energy evaporation crystallization process, and realizing the green and efficient recovery of waste denitration catalysts.

Description

A method for preparing titanium-silicon carrier by recovering waste denitrification catalyst

technical field

The invention relates to a method for recovering and preparing a titanium-silicon carrier from a waste denitrification catalyst, and belongs to the field of flue gas denitrification and material recycling.

Background technique

The waste denitrification catalyst is a hazardous waste stipulated in the "National Hazardous Waste List". Its environmental risk is extremely high, but its recycling value is extremely high. In 2014, the Ministry of Ecology and Environment issued the "Notice on Strengthening the Supervision of Waste Flue Gas Denitrification Catalysts", which requires improving the regeneration and utilization of waste flue gas denitrification catalysts, encouraging priority regeneration, and implementing safe disposal of waste denitrification catalysts that cannot be regenerated .

Existing waste denitrification catalyst resource recovery and reuse technology generally adopts recovery processes such as sodium roasting, calcification roasting, and alkali leaching. First, silicon-containing dust and alkali metal ions are removed to extract vanadium, tungsten, and titanium components sequentially. Among them, the vanadium and tungsten components are Ammonium vanadate and ammonium tungstate are mainly obtained through ammonia crystallization, while the titanium component reacts with alkali to form sodium titanate and other salts, and further obtains TiO ₂ through acid elution of sodium; or simply washes and beats the spent denitrification catalyst , Dry and reuse directly. The process of using alkali fusion is complicated, the recovery of vanadium and tungsten through evaporation and crystallization consumes a lot of energy, and the waste liquid generated in the process of recovering TiO ₂ is large, and the product quality is poor when it is simply washed and reused.

Patent CN107557599A discloses a method for recovering tungsten and vanadium from waste SCR denitrification catalyst, including pretreatment, lye leaching, acidification desiliconization, calcification precipitation, formic acid dissolution of vanadium, vanadium liquid acidification, ammonia water precipitation of vanadium, calcium tungstate acid leaching , roasting step, to obtain V ₂ O ₅ and WO ₃ , but the alkali leaching uses a high concentration of alkali of 10-40%, so that TiO ₂ and SiO ₂ also react, and a complicated silicon removal process is required in the follow-up, And because the silicon removal process needs to adjust the pH to 7.5-9.5, not only need to use a large amount of acid, but also the lye is neutralized, and its reuse value is low. Patent CN109536721A discloses a method for comprehensive utilization of waste SCR denitrification catalyst resources, including pretreatment, crushing, grinding, ultrasonic enhanced alkali leaching, liquid-solid separation, ion exchange, desorption and chemical precipitation, cleaning and drying, optional Vanadium, tungsten, and titanium are used as raw materials for related industries. However, this process uses high alkali concentration and preferential pressure alkali leaching, resulting in TiO ₂ reacting with alkali to form titanate, and then preparing TiO _2. The process is complicated and energy-consuming. , and the alkali will react with the _SiO2 of the waste denitration catalyst to form water glass, resulting in poor quality of vanadium and tungsten products.

Contents of the invention

Both TiO ₂ and SiO ₂ are commonly used supports for catalysts, and titanium-silicon supports are also commonly used in the field of denitration catalysts. The content of TiO ₂ in the waste denitration catalyst is high. During the preparation process, molding aids such as clay are added to enhance the structural strength of the catalyst, resulting in a certain amount of SiO ₂ in the catalyst, which is difficult to remove during the recovery process. Coal ash also has _SiO2 as the main component, which is difficult to remove during recycling, and the process is complex and difficult.

In view of the above problems, the present invention provides a method for recovering waste denitrification catalysts to prepare titanium-silicon carriers. After the waste denitrification catalysts are crushed and ground, they are subjected to alkali leaching, and vanadium, tungsten and alkali metal impurity ions are dissolved into the liquid phase. By controlling the reaction conditions So that titanium and silicon do not participate in the reaction, the titanium and silicon components can be separated after filtration, and prepared as a titanium silicon carrier for reuse to prepare a denitration catalyst, and the lye is reused after precipitation and recovery of vanadium and tungsten, realizing the green energy saving and high efficiency of the waste denitration catalyst Recycle.

The present invention is achieved through the following technical solutions:

A method for recovering and preparing a titanium-silicon carrier from a waste denitrification catalyst, which is characterized in that it includes the steps of pretreatment, alkali leaching, and filtration to obtain a filtrate and a filter residue, and the filtrate is further precipitated in vanadium, tungsten, and dried to obtain a calcium tungstate product, and the filter residue is acid-milled, Washing with water and drying to obtain a titanium-silicon carrier, as well as acid and alkali solution neutralization to remove impurities and reuse; the alkali leaching can be carried out in two ways: caustic soda alkali leaching and ammonia water alkali leaching.

Further, the pretreatment includes vacuuming, crushing and pre-grinding;

The dust suction is to absorb floating dust on the surface of the spent denitrification catalyst, and the suction force is set at 300-980mbar. The use of low-pressure vacuuming can reduce energy consumption, and mainly remove the floating dust on the surface of the waste denitrification catalyst rich in alkali metal ions, without removing the fly ash and other substances with _SiO2 as the main component that are blocked in the pores.

The crushing is to mechanically crush the waste denitrification catalyst after vacuuming to 1-10 mm; the pre-grinding is to grind the crushed waste denitrification catalyst to an average particle size of 5-100 μm to obtain waste denitrification catalyst powder, which is beneficial to the alkali leaching reaction carried out.

Furthermore, the existing process mostly uses high-concentration NaOH solution for pressurized alkali leaching, which can easily cause TiO ₂ and SiO ₂ to react with NaOH, thereby obtaining sodium titanate and then acid washing to obtain TiO ₂ , while SiO ₂ reacts to form water glass Seriously affect the quality of vanadium tungsten products. Here, low-concentration NaOH is used to react in a stirred reactor, and the specific concentration of NaOH is determined according to the total content of vanadium and tungsten in the spent denitrification catalyst powder and the liquid-solid ratio, which can avoid the reaction of TiO ₂ and well inhibit the occurrence of SiO ₂ Reaction, generally the reaction of SiO ₂ and NaOH needs to be pressurized, and the reaction is very slow without pressurization.

The main reactions that may occur in the caustic soda leaching process are as follows:

V ₂ O ₅ +6NaOH＝2Na ₃ VO ₄ +3H ₂ O (1)

WO ₃ +2NaOH=Na ₂ WO ₄ +H ₂ O (2)

SiO ₂ +2NaOH=Na ₂ SiO ₃ +H ₂ O (3)

TiO ₂ +2NaOH=Na ₂ TiO ₃ +H ₂ O (4)

The Gibbs free energy change of the above reaction at 40-80°C is obtained by calculation. As shown in Table 1, the Gibbs free energy change of the reaction of V ₂ O ₅ and WO ₃ with NaOH is significantly greater than that of the reaction of SiO ₂ and TiO ₂ with NaOH Gibbs free energy change, reaction (1) and reaction (2) are more likely to occur than reaction (3) and reaction (4) from thermodynamics, so V ₂ O ₅ and WO ₃ can be prioritized by controlling the reaction conditions SiO ₂ and TiO ₂ are retained by leaching to obtain a titanium silicon component.

Table 1 Gibbs free energy change ΔG/kJ of reactions (1)-(4) at 40-80°C

The caustic soda leaching of the present invention is specifically to configure 0.5-9wt.% NaOH solution and waste denitrification catalyst powder according to the liquid-solid mass ratio of 100: (20-50) into the stirring reactor, and set the alkali leaching temperature to 40-100 ℃, the alkali leaching time is 0.5-4h, and the stirring speed is 30-120r/min.

Further, the ammonia water alkali leaching of the present invention is specifically configured to add 2-10wt.% ammonia solution and waste denitrification catalyst powder into the stirring reactor according to the liquid-solid mass ratio of 100:(20-50), and set the alkali leaching temperature to 50-130℃, the alkali leaching pressure is 0.1-0.3MPa, the alkali leaching time is 0.5-4h, and the stirring speed is 30-120r/min. Ammonia water can react with V ₂ O ₅ and WO ₃ during ammonia water alkaline leaching, but not with SiO ₂ and TiO ₂ , so the reaction temperature and pressure can be increased to speed up the leaching reaction, but the concentration of ammonia water still needs to be controlled during the reaction process. High will cause the leached vanadium to precipitate ammonium vanadate crystals.

The main reactions that may occur in the ammoniacal alkali leaching process are as follows:

V ₂ O ₅ +2NH ₃ ·H ₂ O＝2NH ₄ VO ₃ +H ₂ O (5)

WO ₃ +2NH ₃ ·H ₂ O=(NH ₄ ) ₂ WO ₄ +H ₂ O (6)

Further, solid-liquid separation is carried out after alkali leaching to obtain filter residue and filtrate, and vanadium and tungsten elements are precipitated and extracted from the filtrate.

The caustic soda leaching method can be filtered at room temperature or at the alkali leaching temperature, and the ammonia water alkali leaching method should be carried out at a higher temperature, that is, after the alkali leaching is completed, the system should be filtered in time to prevent the precipitation of ammonium vanadate during the cooling process.

Further, the vanadium precipitation method in the filtrate of the caustic soda leaching method is as follows: analyze the content of vanadium and tungsten elements in the filtrate, add one or both of CaO or Ca(OH) for precipitation, and the addition amount is _2% of the total content of vanadium and tungsten elements. 0.9-1.0 times, the precipitation reaction temperature is 20-35°C, the precipitation reaction time is 1.5-4 hours, the stirring speed is 30-120r/min, then filtered and dried to obtain the vanadium tungsten product and the filtrate with calcium tungstate as the main product , the filtrate is lye back to the alkali leaching step.

Due to the low vanadium content in waste denitrification catalysts, its recovery has great social significance but the economic value of separate recovery is not high, so manufacturers generally do not consider the recovery of vanadium in actual production, and usually obtain sodium tungstate by evaporation and crystallization products, but the energy consumption of evaporation and crystallization is high, and the reuse of water after condensation also increases the process, and the water consumption is too large if the water is not reused. Therefore, calcium precipitation is adopted here, and the leached vanadium and tungsten are precipitated by calcium ions, then filtered and dried to obtain vanadium and tungsten products, and the filtrate can be directly reused, avoiding the high energy consumption of evaporation and crystallization, and the water can be Reuse directly. Although the solubility product of Ca(OH) ₂ is 3 orders of magnitude different from that of CaWO ₄ , the solubility product of Ca(OH) ₂ is not large, so the precipitation reaction time is set to 1.5-4 hours to fully precipitate tungsten.

Ammonia water alkaline leaching method The method of sinking vanadium and tungsten in the filtrate is as follows: after the filtrate is cooled to 20-40°C, add ammonia water to adjust the mass fraction of ammonia water to greater than 9wt.%, then filter and dry to obtain ammonium vanadate product; cooling the filtrate can reduce vanadate The solubility of ammonium is further added to control the concentration of vanadium to be lower than 0.01mol/L, that is, the vanadium is separated by a simple method, and the ammonium vanadate product is obtained. Further add one or both of CaO or Ca(OH) ₂ for precipitation, the amount added is 0.9-1.0 times the total content of tungsten element, the precipitation reaction temperature is 20-35°C, and the precipitation reaction time is 0.5-2 hours, The stirring speed is 30-120r/min, and then filtered and dried to obtain calcium tungstate and filtrate, and the filtrate is alkaline solution to be used in the alkaline leaching step. It also avoids the high energy consumption of evaporative crystallization, and the water can be reused directly.

The vanadium component can also be separated by adding amino ions in the caustic soda immersion solution, but the vanadium content is not high, so it can be ignored in practice.

Further, the filter residue after alkali leaching is acid milled, and the acid mill is wet milled by adding one or both of sulfuric acid or nitric acid, and the pH of the acid solution is controlled to be less than or equal to 3, and the liquid-solid ratio is (30-80):100. The average particle size is less than 15 μm; adding acid for grinding can deeply remove impurities such as alkali metal ions in the titanium-silicon carrier, and promote the fusion of titanium and silicon components.

Further, the water washing is washing with water after acid milling to remove impurities, and further drying to obtain the titanium silicon carrier. The main goal of this method is to obtain a titanium-silicon carrier, thus avoiding the complicated silicon removal process.

Further, after 2-5 times of vanadium and tungsten precipitation in the filtrate, impurities need to be removed. The impurity removal method is to neutralize the acid solution after acid grinding and water washing with the alkaline filtrate after vanadium and tungsten precipitation, and then add excess Ca ions and a small amount of barium Ions remove sulfur, phosphorus, arsenic and other impurities, and filter to obtain reusable water.

Compared with patents CN107557599A and CN109536721A, the present invention has outstanding features in that it controls the alkali leaching reaction process, retains _TiO2 and _SiO2 components, and prepares it as a titanium-silicon carrier, while the above patents all use a stronger alkali leaching method , resulting in the reaction of TiO ₂ and SiO ₂ with NaOH, which complicates the recovery of TiO ₂ and increases the silicon removal process.

The beneficial technical effect of the present invention is:

(1) The titanium-silicon carrier is prepared from the waste denitration catalyst, which avoids the complicated silicon removal process, but uses the difficult-to-remove silicon as a valuable component, which broadens the existing thinking of recycling TiO ₂ ;

(2) By controlling the reaction process and inhibiting the reaction of _SiO2 and _TiO2 in the alkaline leaching process, vanadium and tungsten are leached in a relatively energy-saving manner while retaining the _SiO2 and _TiO2 components;

(3) Precipitation and separation of vanadium and tungsten components by CaO or Ca(OH) ₂ avoids the high-energy evaporation crystallization process, and the obtained calcium tungstate and other products have the same economic value as sodium tungstate.

Drawings

Fig. 1 is a process flow diagram of the method of the present invention.

Detailed ways

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with specific embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention, and those skilled in the art can fully understand the present invention without the description of these details. The present invention covers any alternatives, modifications, equivalent methods and schemes made on the spirit and scope of the present invention as defined by the claims.

Implementation Case 1

As shown in Figure 1, a method for recovering and preparing a titanium-silicon carrier from a waste denitration catalyst includes pretreatment, alkali leaching, and filtration to obtain filtrate and filter residue, further filtrate precipitation of vanadium, precipitation of tungsten, and drying to obtain calcium tungstate products, acid grinding of filter residue, and water washing , drying to obtain a titanium-silicon carrier, and acid and alkali neutralization and removal of impurities and reuse.

Pretreatment includes vacuuming, crushing and pre-grinding. The suction is set at 980mbar, crushed to 1-10mm, and pre-ground to an average particle size of 5-100μm to obtain spent denitrification catalyst powder. For further caustic soda leaching, configure 0.5wt.% NaOH solution and waste denitrification catalyst powder into the stirring reactor according to the liquid-solid mass ratio of 100:50, set the alkali leaching temperature to 40°C, the alkali leaching time to 0.5h, and the stirring speed to 30r/min, alkali leaching and filtration to obtain filter residue and filtrate. Add one or both of CaO or Ca(OH) ₂ to the filtrate for precipitation, the amount added is 0.9 times the total content of vanadium and tungsten elements, the precipitation reaction temperature is 20°C, the precipitation reaction time is 1.5 hours, the stirring speed 30r/min, then filter and dry to obtain vanadium tungsten product and filtrate with calcium tungstate as the main product, and the filtrate is alkali liquor and is used for alkali leaching step.

Further, acid mill the filter residue after alkali leaching, add one or both of sulfuric acid or nitric acid for wet milling, control the pH of the acid solution to be ≤3, the liquid-solid ratio is 30:100, and grind until the average particle size is less than 15 μm, Then wash with water and dry to obtain the titanium silicon carrier. The filtrate needs to remove impurities after vanadium and tungsten precipitation twice. The impurity removal method is to neutralize the acid solution after acid grinding and water washing with the alkaline filtrate after vanadium and tungsten precipitation, and then add excess Ca ions and a small amount of barium ions to remove sulfur and phosphorus. , arsenic and other impurities, filtered to obtain reusable water.

Implementation Case 2

A method for recovering waste denitrification catalysts to prepare titanium-silicon carriers, including pretreatment, alkali leaching, and filtration to obtain filtrate and filter residue, further precipitating vanadium, tungsten, and drying the filtrate to obtain calcium tungstate products, acid milling the filter residue, washing with water, and drying to obtain titanium Silicon carrier, as well as acid and alkali neutralization, impurity removal and reuse.

Pretreatment includes vacuuming, crushing and pre-grinding. The suction is set at 900mbar, crushed to 1-9mm, and pre-ground to an average particle size of 5-90μm to obtain spent denitrification catalyst powder. For further caustic soda leaching, configure 1.5wt.% NaOH solution and waste denitrification catalyst powder into the stirring reactor according to the liquid-solid mass ratio of 100:45, set the alkali leaching temperature to 50°C, the alkali leaching time to 1h, and the stirring speed to 40r /min, alkali leaching and filtration to obtain filter residue and filtrate. Add one or both of CaO or Ca(OH) ₂ to the filtrate for precipitation, the amount added is 0.9 times the total content of vanadium and tungsten elements, the precipitation reaction temperature is 25 ° C, the precipitation reaction time is 2 hours, the stirring speed 40r/min, then filter and dry to obtain vanadium tungsten product and filtrate with calcium tungstate as the main product, and the filtrate is alkaline solution and is used in the alkaline leaching step.

Further, acid mill the filter residue after alkali leaching, add one or both of sulfuric acid or nitric acid for wet milling, control the pH of the acid solution to be ≤3, the liquid-solid ratio is 40:100, and grind until the average particle size is less than 14 μm, Then wash with water and dry to obtain the titanium silicon carrier. The filtrate needs to remove impurities after 3 times of vanadium and tungsten precipitation. The impurity removal method is to neutralize the acid solution after acid grinding and water washing with the alkaline filtrate after vanadium and tungsten precipitation, and then add excess Ca ions and a small amount of barium ions to remove sulfur and phosphorus. , arsenic and other impurities, filtered to obtain reusable water.

Implementation Case 3

A method for recovering waste denitrification catalysts to prepare titanium-silicon carriers, including pretreatment, alkali leaching, and filtration to obtain filtrate and filter residue, further precipitating vanadium, tungsten, and drying the filtrate to obtain calcium tungstate products, acid milling the filter residue, washing with water, and drying to obtain titanium Silicon carrier, as well as acid and alkali neutralization, impurity removal and reuse.

Pretreatment includes vacuuming, crushing and pre-grinding. The suction is set at 850mbar, crushed to 1-8mm, and pre-ground to an average particle size of 5-80μm to obtain spent denitrification catalyst powder. For further caustic soda leaching, configure 2wt.% NaOH solution and waste denitrification catalyst powder into the stirring reactor according to the liquid-solid mass ratio of 100:40, set the alkali leaching temperature to 60°C, the alkali leaching time to 1.5h, and the stirring speed to 50r /min, alkali leaching and filtration to obtain filter residue and filtrate. Add one or both of CaO or Ca(OH) ₂ to the filtrate for precipitation, the amount added is 0.9 times the total content of vanadium and tungsten elements, the precipitation reaction temperature is 30°C, the precipitation reaction time is 2.5 hours, the stirring speed 50r/min, then filter and dry to obtain vanadium tungsten product and filtrate with calcium tungstate as the main product.

Further, acid mill the filter residue after alkali leaching, add one or both of sulfuric acid or nitric acid for wet milling, control the pH of the acid solution to be ≤3, the liquid-solid ratio is 50:100, and grind until the average particle size is less than 13 μm, Then wash with water and dry to obtain the titanium silicon carrier. The filtrate needs to remove impurities after vanadium and tungsten precipitation for 4 times. The impurity removal method is to neutralize the acid solution after acid grinding and water washing with the alkaline filtrate after vanadium and tungsten precipitation, and then add excess Ca ions and a small amount of barium ions to remove sulfur and phosphorus. , arsenic and other impurities, filtered to obtain reusable water.

Implementation Case 4

A method for recovering waste denitrification catalysts to prepare titanium-silicon carriers, including pretreatment, alkali leaching, and filtration to obtain filtrate and filter residue, further precipitating vanadium, tungsten, and drying the filtrate to obtain calcium tungstate products, acid milling the filter residue, washing with water, and drying to obtain titanium Silicon carrier, as well as acid and alkali neutralization, impurity removal and reuse.

Pretreatment includes vacuuming, crushing and pre-grinding. The suction is set at 800mbar, crushed to 1-7mm, and pre-ground to an average particle size of 5-70μm to obtain spent denitrification catalyst powder. For further caustic soda leaching, configure 2.5wt.% NaOH solution and waste denitrification catalyst powder into the stirring reactor at a liquid-solid mass ratio of 100:35, set the alkali leaching temperature to 70°C, the alkali leaching time to 2h, and the stirring speed to 60r /min, alkali leaching and filtration to obtain filter residue and filtrate. Add one or both of CaO or Ca(OH) ₂ to the filtrate for precipitation, the amount added is 0.95 times the total content of vanadium and tungsten elements, the precipitation reaction temperature is 35 ° C, the precipitation reaction time is 3 hours, the stirring speed 60r/min, then filter and dry to obtain vanadium tungsten product and filtrate with calcium tungstate as the main product, and the filtrate is alkaline solution and is used in the alkaline leaching step.

Further, acid mill the filter residue after alkali leaching, add one or both of sulfuric acid or nitric acid for wet milling, control the pH of the acid solution to be ≤3, the liquid-solid ratio is 60:100, and grind until the average particle size is less than 12 μm, Then wash with water and dry to obtain the titanium silicon carrier. The filtrate needs to remove impurities after vanadium and tungsten precipitation for 5 times. The impurity removal method is to neutralize the acid solution after acid grinding and water washing with the alkaline filtrate after vanadium and tungsten precipitation, and then add excess Ca ions and a small amount of barium ions to remove sulfur and phosphorus. , arsenic and other impurities, filtered to obtain reusable water.

Implementation Case 5

A method for recovering waste denitrification catalysts to prepare titanium-silicon carriers, including pretreatment, alkali leaching, and filtration to obtain filtrate and filter residue, further precipitating vanadium, tungsten, and drying the filtrate to obtain calcium tungstate products, acid milling the filter residue, washing with water, and drying to obtain titanium Silicon carrier, as well as acid and alkali neutralization, impurity removal and reuse.

Pretreatment includes vacuuming, crushing and pre-grinding. The suction is set at 750mbar, crushed to 1-6mm, and pre-ground to an average particle size of 5-60μm to obtain spent denitrification catalyst powder. For further caustic soda leaching, configure 3wt.% NaOH solution and waste denitrification catalyst powder into the stirring reactor according to the liquid-solid mass ratio of 100:30, set the alkali leaching temperature to 80°C, the alkali leaching time to 2.5h, and the stirring speed to 70r /min, alkali leaching and filtration to obtain filter residue and filtrate. Add one or both of CaO or Ca(OH) ₂ to the filtrate for precipitation, the amount added is 0.95 times the total content of vanadium and tungsten elements, the precipitation reaction temperature is 35 ° C, the precipitation reaction time is 3.5 hours, the stirring speed 70r/min, then filter and dry to obtain vanadium tungsten product and filtrate with calcium tungstate as the main product, and the filtrate is lye and reused in the alkali leaching step.

Further, acid mill the filter residue after alkali leaching, add one or both of sulfuric acid or nitric acid for wet milling, control the pH of the acid solution to be ≤3, the liquid-solid ratio is 70:100, and grind until the average particle size is less than 11 μm, Then wash with water and dry to obtain the titanium silicon carrier. The filtrate needs to remove impurities after vanadium and tungsten precipitation for 5 times. The impurity removal method is to neutralize the acid solution after acid grinding and water washing with the alkaline filtrate after vanadium and tungsten precipitation, and then add excess Ca ions and a small amount of barium ions to remove sulfur and phosphorus. , arsenic and other impurities, filtered to obtain reusable water.

Implementation Case 6

A method for recovering waste denitrification catalysts to prepare titanium-silicon carriers, including pretreatment, alkali leaching, and filtration to obtain filtrate and filter residue, further precipitating vanadium, tungsten, and drying the filtrate to obtain calcium tungstate products, acid milling the filter residue, washing with water, and drying to obtain titanium Silicon carrier, as well as acid and alkali neutralization, impurity removal and reuse.

Pretreatment includes vacuuming, crushing and pre-grinding. The suction is set at 700mbar, crushed to 1-5mm, and pre-ground to an average particle size of 5-50μm to obtain spent denitrification catalyst powder. For further caustic soda leaching, configure 4wt.% NaOH solution and waste denitrification catalyst powder into the stirring reactor according to the liquid-solid mass ratio of 100:25, set the alkali leaching temperature to 90°C, the alkali leaching time to 3.5h, and the stirring speed to 80r /min, alkali leaching and filtration to obtain filter residue and filtrate. Add one or both of CaO or Ca(OH) ₂ to the filtrate for precipitation, the amount added is 0.95 times the total content of vanadium and tungsten elements, the precipitation reaction temperature is 30 ° C, the precipitation reaction time is 4 hours, the stirring speed 80r/min, then filter and dry to obtain vanadium tungsten product and filtrate with calcium tungstate as the main product.

Further, acid mill the filter residue after alkali leaching, add one or both of sulfuric acid or nitric acid for wet milling, control the pH of the acid solution to be ≤3, the liquid-solid ratio is 80:100, and grind until the average particle size is less than 10 μm, Then wash with water and dry to obtain the titanium silicon carrier. The filtrate needs to remove impurities after vanadium and tungsten precipitation for 5 times. The impurity removal method is to neutralize the acid solution after acid grinding and water washing with the alkaline filtrate after vanadium and tungsten precipitation, and then add excess Ca ions and a small amount of barium ions to remove sulfur and phosphorus. , arsenic and other impurities, filtered to obtain reusable water.

Implementation Case 7

A method for recovering waste denitrification catalysts to prepare titanium-silicon carriers, including pretreatment, alkali leaching, and filtration to obtain filtrate and filter residue, further precipitating vanadium, tungsten, and drying the filtrate to obtain calcium tungstate products, acid milling the filter residue, washing with water, and drying to obtain titanium Silicon carrier, as well as acid and alkali neutralization, impurity removal and reuse.

Pretreatment includes vacuuming, crushing and pre-grinding. The suction is set at 650mbar, crushed to 1-4mm, and pre-ground to an average particle size of 5-40μm to obtain spent denitrification catalyst powder. For further caustic soda leaching, configure 5wt.% NaOH solution and waste denitrification catalyst powder into the stirring reactor according to the liquid-solid mass ratio of 100:20, set the alkali leaching temperature to 100°C, the alkali leaching time to 4h, and the stirring speed to 90r/ min, alkali leaching and filtration to obtain the filter residue and filtrate. Add one or both of CaO or Ca(OH) ₂ to the filtrate for precipitation, the amount added is 0.95 times the total content of vanadium and tungsten elements, the precipitation reaction temperature is 25 °C, the precipitation reaction time is 4 hours, the stirring speed 90r/min, then filter and dry to obtain vanadium tungsten product and filtrate with calcium tungstate as the main product, and the filtrate is alkaline solution and reused in the alkaline leaching step.

Further, acid mill the filter residue after alkali leaching, add one or both of sulfuric acid or nitric acid for wet milling, control the pH of the acid solution to ≤3, the liquid-solid ratio is 75:100, and grind until the average particle size is less than 9 μm, Then wash with water and dry to obtain the titanium silicon carrier. The filtrate needs to remove impurities after vanadium and tungsten precipitation for 4 times. The impurity removal method is to neutralize the acid solution after acid grinding and water washing with the alkaline filtrate after vanadium and tungsten precipitation, and then add excess Ca ions and a small amount of barium ions to remove sulfur and phosphorus. , arsenic and other impurities, filtered to obtain reusable water.

Implementation Case 8

A method for recovering waste denitrification catalysts to prepare titanium-silicon carriers, including pretreatment, alkali leaching, and filtration to obtain filtrate and filter residue, further precipitating vanadium, tungsten, and drying the filtrate to obtain calcium tungstate products, acid milling the filter residue, washing with water, and drying to obtain titanium Silicon carrier, as well as acid and alkali neutralization, impurity removal and reuse.

Pretreatment includes vacuuming, crushing and pre-grinding. The suction is set at 600mbar, crushed to 1-3mm, and pre-ground to an average particle size of 5-30μm to obtain spent denitrification catalyst powder. For further caustic soda leaching, configure 6wt.% NaOH solution and waste denitrification catalyst powder into the stirring reactor according to the liquid-solid mass ratio of 100:50, set the alkali leaching temperature to 100°C, the alkali leaching time to 3.5h, and the stirring speed to 100r /min, alkali leaching and filtration to obtain filter residue and filtrate. Add one or both of CaO or Ca(OH) ₂ to the filtrate for precipitation. The amount added is 1 times the total content of vanadium and tungsten elements. The precipitation reaction temperature is 25 ° C. The precipitation reaction time is 3.5 hours. The stirring speed 100r/min, then filter and dry to obtain vanadium tungsten product and filtrate with calcium tungstate as the main product, and the filtrate is lye and reused in the alkali leaching step.

Further, acid mill the filter residue after alkali leaching, add one or both of sulfuric acid or nitric acid for wet milling, control the pH of the acid solution to be ≤3, the liquid-solid ratio is 65:100, and grind until the average particle size is less than 10 μm, Then wash with water and dry to obtain the titanium silicon carrier. The filtrate needs to remove impurities after 3 times of vanadium and tungsten precipitation. The impurity removal method is to neutralize the acid solution after acid grinding and water washing with the alkaline filtrate after vanadium and tungsten precipitation, and then add excess Ca ions and a small amount of barium ions to remove sulfur and phosphorus. , arsenic and other impurities, filtered to obtain reusable water.

Implementation Case 9

A method for recovering waste denitrification catalysts to prepare titanium-silicon carriers, including pretreatment, alkali leaching, and filtration to obtain filtrate and filter residue, further precipitating vanadium, tungsten, and drying the filtrate to obtain calcium tungstate products, acid milling the filter residue, washing with water, and drying to obtain titanium Silicon carrier, as well as acid and alkali neutralization, impurity removal and reuse.

Pretreatment includes vacuuming, crushing and pre-grinding. The suction is set at 550mbar, crushed to 1-3mm, and pre-ground to an average particle size of 5-30μm to obtain spent denitrification catalyst powder. For further caustic soda leaching, configure 7wt.% NaOH solution and waste denitrification catalyst powder into the stirring reactor according to the liquid-solid mass ratio of 100:45, set the alkali leaching temperature to 95°C, the alkali leaching time to 3h, and the stirring speed to 110r/ min, alkali leaching and filtration to obtain the filter residue and filtrate. Add one or both of CaO or Ca(OH) ₂ to the filtrate for precipitation. The amount added is 1 times the total content of vanadium and tungsten elements. The precipitation reaction temperature is 25 ° C. The precipitation reaction time is 3 hours. The stirring speed It is 110r/min, then filtered and dried to obtain vanadium tungsten product and filtrate with calcium tungstate as the main product, and the filtrate is lye and reused in the alkali leaching step.

Further, acid mill the filter residue after alkali leaching, add one or both of sulfuric acid or nitric acid for wet milling, control the pH of the acid solution to be ≤3, the liquid-solid ratio is 55:100, and grind until the average particle size is less than 11 μm, Then wash with water and dry to obtain the titanium silicon carrier. The filtrate needs to remove impurities after 3 times of vanadium and tungsten precipitation. The impurity removal method is to neutralize the acid solution after acid grinding and water washing with the alkaline filtrate after vanadium and tungsten precipitation, and then add excess Ca ions and a small amount of barium ions to remove sulfur and phosphorus. , arsenic and other impurities, filtered to obtain reusable water.

Implementation Case 10

A method for recovering waste denitrification catalysts to prepare titanium-silicon carriers, including pretreatment, alkali leaching, and filtration to obtain filtrate and filter residue, further precipitating vanadium, tungsten, and drying the filtrate to obtain calcium tungstate products, acid milling the filter residue, washing with water, and drying to obtain titanium Silicon carrier, as well as acid and alkali neutralization, impurity removal and reuse.

Pretreatment includes vacuuming, crushing and pre-grinding. The suction is set at 500mbar, crushed to 1-4mm, and pre-ground to an average particle size of 5-45μm to obtain spent denitrification catalyst powder. For further caustic soda leaching, configure 8wt.% NaOH solution and waste denitrification catalyst powder into the stirring reactor at a liquid-solid mass ratio of 100:35, set the alkali leaching temperature to 85°C, the alkali leaching time to 2.5h, and the stirring speed to 120r /min, alkali leaching and filtration to obtain filter residue and filtrate. Add one or both of CaO or Ca(OH) ₂ to the filtrate for precipitation. The amount added is 1 times the total content of vanadium and tungsten elements. The precipitation reaction temperature is 20°C, the precipitation reaction time is 3 hours, and the stirring speed 120r/min, then filter and dry to obtain vanadium tungsten product and filtrate with calcium tungstate as the main product, and the filtrate is alkali liquor and is used for alkali leaching step.

Further, acid mill the filter residue after alkali leaching, add one or both of sulfuric acid or nitric acid for wet milling, control the pH of the acid solution to ≤3, the liquid-solid ratio is 45:100, and grind until the average particle size is less than 12 μm, Then wash with water and dry to obtain the titanium silicon carrier. The filtrate needs to remove impurities after 3 times of vanadium and tungsten precipitation. The impurity removal method is to neutralize the acid solution after acid grinding and water washing with the alkaline filtrate after vanadium and tungsten precipitation, and then add excess Ca ions and a small amount of barium ions to remove sulfur and phosphorus. , arsenic and other impurities, filtered to obtain reusable water.

Implementation Case 11

A method for recovering waste denitrification catalysts to prepare titanium-silicon carriers, including pretreatment, alkali leaching, and filtration to obtain filtrate and filter residue, further precipitating vanadium, tungsten, and drying the filtrate to obtain calcium tungstate products, acid milling the filter residue, washing with water, and drying to obtain titanium Silicon carrier, as well as acid and alkali neutralization, impurity removal and reuse.

Pretreatment includes vacuuming, crushing and pre-grinding. The suction is set at 450mbar, crushed to 1-6mm, and pre-ground to an average particle size of 5-55μm to obtain spent denitrification catalyst powder. For further caustic soda leaching, configure 9wt.% NaOH solution and waste denitrification catalyst powder into the stirring reactor according to the liquid-solid mass ratio of 100:50, set the alkali leaching temperature to 75°C, the alkali leaching time to 2h, and the stirring speed to 110r/ min, alkali leaching and filtration to obtain the filter residue and filtrate. Add one or both of CaO or Ca(OH) ₂ to the filtrate for precipitation, the amount added is 1 times the total content of vanadium and tungsten elements, the precipitation reaction temperature is 25 °C, the precipitation reaction time is 4 hours, the stirring speed It is 110r/min, then filtered and dried to obtain vanadium tungsten product and filtrate with calcium tungstate as the main product, and the filtrate is lye and reused in the alkali leaching step.

Further, acid mill the filter residue after alkali leaching, add one or both of sulfuric acid or nitric acid for wet milling, control the pH of the acid solution to be ≤3, the liquid-solid ratio is 40:100, and grind until the average particle size is less than 13 μm, Then wash with water and dry to obtain the titanium silicon carrier. The filtrate needs to remove impurities after vanadium and tungsten precipitation for 4 times. The impurity removal method is to neutralize the acid solution after acid grinding and water washing with the alkaline filtrate after vanadium and tungsten precipitation, and then add excess Ca ions and a small amount of barium ions to remove sulfur and phosphorus. , arsenic and other impurities, filtered to obtain reusable water.

Implementation Case 12

A method for recovering waste denitrification catalysts to prepare titanium-silicon carriers, including pretreatment, alkali leaching, and filtration to obtain filtrate and filter residue, further precipitating vanadium, tungsten, and drying the filtrate to obtain calcium tungstate products, acid milling the filter residue, washing with water, and drying to obtain titanium Silicon carrier, as well as acid and alkali neutralization, impurity removal and reuse.

Pretreatment includes vacuuming, crushing and pre-grinding. The suction is set at 400mbar, crushed to 1-7mm, and pre-ground to an average particle size of 5-65μm to obtain spent denitrification catalyst powder. For further caustic soda leaching, configure 8.5wt.% NaOH solution and waste denitrification catalyst powder into the stirring reactor according to the liquid-solid mass ratio of 100:50, set the alkali leaching temperature to 65°C, the alkali leaching time to 1.5h, and the stirring speed to 100r/min, alkali leaching and filtration to obtain filter residue and filtrate. Add one or both of CaO or Ca(OH) ₂ to the filtrate for precipitation. The amount added is 0.95 times the total content of vanadium and tungsten elements. The precipitation reaction temperature is 20 ° C. The precipitation reaction time is 3.5 hours. The stirring speed 100r/min, then filter and dry to obtain vanadium tungsten product and filtrate with calcium tungstate as the main product, and the filtrate is lye and reused in the alkali leaching step.

Further, acid mill the filter residue after alkali leaching, add one or both of sulfuric acid or nitric acid for wet milling, control the pH of the acid solution to be ≤3, the liquid-solid ratio is 30:100, and grind until the average particle size is less than 15 μm, Then wash with water and dry to obtain the titanium silicon carrier. The filtrate needs to remove impurities after vanadium and tungsten precipitation for 4 times. The impurity removal method is to neutralize the acid solution after acid grinding and water washing with the alkaline filtrate after vanadium and tungsten precipitation, and then add excess Ca ions and a small amount of barium ions to remove sulfur and phosphorus. , arsenic and other impurities, filtered to obtain reusable water.

Implementation Case 13

A method for recovering waste denitrification catalysts to prepare titanium-silicon carriers, including pretreatment, alkali leaching, and filtration to obtain filtrate and filter residue, further precipitating vanadium, tungsten, and drying the filtrate to obtain calcium tungstate products, acid milling the filter residue, washing with water, and drying to obtain titanium Silicon carrier, as well as acid and alkali neutralization, impurity removal and reuse.

Pretreatment includes vacuuming, crushing and pre-grinding. The suction is set at 350mbar, crushed to 1-8mm, and pre-ground to an average particle size of 5-75μm to obtain spent denitrification catalyst powder. For further caustic soda leaching, configure 7.5wt.% NaOH solution and waste denitrification catalyst powder into the stirring reactor at a liquid-to-solid mass ratio of 100:40, set the alkali leaching temperature to 55°C, the alkali leaching time to 3h, and the stirring speed to 90r /min, alkali leaching and filtration to obtain filter residue and filtrate. Add one or both of CaO or Ca(OH) ₂ to the filtrate for precipitation, the amount added is 1 times the total content of vanadium and tungsten elements, the precipitation reaction temperature is 25 °C, the precipitation reaction time is 1.5 hours, the stirring speed 35r/min, then filter and dry to obtain vanadium tungsten product and filtrate with calcium tungstate as the main product, and the filtrate is lye and reused in the alkali leaching step.

Further, acid mill the filter residue after alkali leaching, add one or both of sulfuric acid or nitric acid for wet milling, control the pH of the acid solution to be ≤3, the liquid-solid ratio is 35:100, and grind until the average particle size is less than 7 μm, Then wash with water and dry to obtain the titanium silicon carrier. The filtrate needs to remove impurities after vanadium and tungsten precipitation twice. The impurity removal method is to neutralize the acid solution after acid grinding and water washing with the alkaline filtrate after vanadium and tungsten precipitation, and then add excess Ca ions and a small amount of barium ions to remove sulfur and phosphorus. , arsenic and other impurities, filtered to obtain reusable water.

Implementation Case 14

A method for recovering waste denitrification catalysts to prepare titanium-silicon carriers, including pretreatment, alkali leaching, and filtration to obtain filtrate and filter residue, further precipitating vanadium, tungsten, and drying the filtrate to obtain calcium tungstate products, acid milling the filter residue, washing with water, and drying to obtain titanium Silicon carrier, as well as acid and alkali neutralization, impurity removal and reuse.

Pretreatment includes vacuuming, crushing and pre-grinding. The suction is set at 300mbar, crushed to 1-9mm, and pre-ground to an average particle size of 5-85μm to obtain spent denitrification catalyst powder. For further caustic soda leaching, configure 6.5wt.% NaOH solution and waste denitrification catalyst powder into the stirring reactor according to the liquid-solid mass ratio of 100:30, set the alkali leaching temperature to 45°C, the alkali leaching time to 1h, and the stirring speed to 80r /min, alkali leaching and filtration to obtain filter residue and filtrate. Add one or both of CaO or Ca(OH) ₂ to the filtrate for precipitation, the amount added is 0.95 times the total content of vanadium and tungsten elements, the precipitation reaction temperature is 25 °C, the precipitation reaction time is 2 hours, the stirring speed 55r/min, then filter and dry to obtain vanadium tungsten product and filtrate with calcium tungstate as the main product, and the filtrate is lye and reused in the alkali leaching step.

Further, acid mill the filter residue after alkali leaching, add one or both of sulfuric acid or nitric acid for wet milling, control the pH of the acid solution to be ≤3, the liquid-solid ratio is 45:100, and grind until the average particle size is less than 8 μm, Then wash with water and dry to obtain the titanium silicon carrier. The filtrate needs to remove impurities after 3 times of vanadium and tungsten precipitation. The impurity removal method is to neutralize the acid solution after acid grinding and water washing with the alkaline filtrate after vanadium and tungsten precipitation, and then add excess Ca ions and a small amount of barium ions to remove sulfur and phosphorus. , arsenic and other impurities, filtered to obtain reusable water.

Implementation Case 15

A method for recovering waste denitrification catalysts to prepare titanium-silicon carriers, including pretreatment, alkali leaching, and filtration to obtain filtrate and filter residue, further precipitating vanadium, tungsten, and drying the filtrate to obtain calcium tungstate products, acid milling the filter residue, washing with water, and drying to obtain titanium Silicon carrier, as well as acid and alkali neutralization, impurity removal and reuse.

Pretreatment includes vacuuming, crushing and pre-grinding. The suction is set at 300mbar, crushed to 1-10mm, and pre-ground to an average particle size of 5-95μm to obtain spent denitrification catalyst powder. For further caustic soda leaching, configure 9wt.% NaOH solution and waste denitrification catalyst powder into the stirring reactor at a liquid-solid mass ratio of 100:20, set the alkali leaching temperature to 100°C, the alkali leaching time to 0.5h, and the stirring speed to 70r /min, alkali leaching and filtration to obtain filter residue and filtrate. Add one or both of CaO or Ca(OH) ₂ to the filtrate for precipitation, the amount added is 0.9 times the total content of vanadium and tungsten elements, the precipitation reaction temperature is 25 ° C, the precipitation reaction time is 4 hours, the stirring speed 120r/min, then filter and dry to obtain vanadium tungsten product and filtrate with calcium tungstate as the main product, and the filtrate is alkali liquor and is used for alkali leaching step.

Further, acid mill the filter residue after alkali leaching, add one or both of sulfuric acid or nitric acid for wet milling, control the pH of the acid solution to be ≤3, the liquid-solid ratio is 55:100, and grind until the average particle size is less than 9 μm, Then wash with water and dry to obtain the titanium silicon carrier. The filtrate needs to remove impurities after vanadium and tungsten precipitation for 4 times. The impurity removal method is to neutralize the acid solution after acid grinding and water washing with the alkaline filtrate after vanadium and tungsten precipitation, and then add excess Ca ions and a small amount of barium ions to remove sulfur and phosphorus. , arsenic and other impurities, filtered to obtain reusable water.

Implementation Case 16

A method for recovering waste denitrification catalysts to prepare titanium-silicon carriers, including pretreatment, alkali leaching, and filtration to obtain filtrate and filter residue, further precipitating vanadium, tungsten, and drying the filtrate to obtain calcium tungstate products, acid milling the filter residue, washing with water, and drying to obtain titanium Silicon carrier, as well as acid and alkali neutralization, impurity removal and reuse.

Pretreatment includes vacuuming, crushing and pre-grinding. The suction is set at 980mbar, crushed to 1-10mm, and pre-ground to an average particle size of 5-100μm to obtain spent denitrification catalyst powder. For further ammonia leaching, configure 2wt.% ammonia solution and spent denitrification catalyst powder into the stirring reactor at a liquid-to-solid mass ratio of 100:50, set the alkali leaching temperature to 50°C, the alkali leaching pressure to 0.1MPa, and the alkali leaching time to 4h, the stirring speed is 30r/min, alkali leaching and filtration to obtain the filter residue and filtrate. After the filtrate is cooled to 40°C, add ammonia water to adjust the mass fraction of ammonia water to be greater than 9wt.%, filter and dry to obtain ammonium vanadate product; further add one or _both of CaO or Ca(OH) for precipitation, and the addition amount is 0.9 times the total content of tungsten elements, the precipitation reaction temperature is 20°C, the precipitation reaction time is 0.5 hours, the stirring speed is 30r/min, then filtered and dried to obtain calcium tungstate and filtrate, the filtrate is alkaline solution and used in the alkaline leaching step .

Further, acid mill the filter residue after alkali leaching, add one or both of sulfuric acid or nitric acid for wet milling, control the pH of the acid solution to be ≤3, the liquid-solid ratio is 30:100, and grind until the average particle size is less than 15 μm, Then wash with water and dry to obtain the titanium silicon carrier. The filtrate needs to remove impurities after vanadium and tungsten precipitation twice. The impurity removal method is to neutralize the acid solution after acid grinding and water washing with the alkaline filtrate after vanadium and tungsten precipitation, and then add excess Ca ions and a small amount of barium ions to remove sulfur and phosphorus. , arsenic and other impurities, filtered to obtain reusable water.

Implementation Case 17

A method for recovering waste denitrification catalysts to prepare titanium-silicon carriers, including pretreatment, alkali leaching, and filtration to obtain filtrate and filter residue, further precipitating vanadium, tungsten, and drying the filtrate to obtain calcium tungstate products, acid milling the filter residue, washing with water, and drying to obtain titanium Silicon carrier, as well as acid and alkali neutralization, impurity removal and reuse.

Pretreatment includes vacuuming, crushing and pre-grinding. The suction is set at 900mbar, crushed to 1-9mm, and pre-ground to an average particle size of 5-90μm to obtain spent denitrification catalyst powder. Further ammonia water alkali leaching, configure 2.5wt.% ammonia solution and waste denitrification catalyst powder into the stirring reactor according to the liquid-solid mass ratio of 100:45, set the alkali leaching temperature to 60°C, the alkali leaching pressure to 0.1MPa, and the alkali leaching time for 3.5 hours, with a stirring speed of 40r/min, alkali leaching and filtration to obtain the filter residue and filtrate. After the filtrate is cooled to 20°C, add ammonia water to adjust the mass fraction of ammonia water to be greater than 9wt.%, filter and dry to obtain ammonium vanadate product; further add one or _both of CaO or Ca(OH) for precipitation, and the addition amount is 0.9 times the total content of tungsten elements, the precipitation reaction temperature is 25°C, the precipitation reaction time is 1 hour, the stirring speed is 40r/min, then filtered and dried to obtain calcium tungstate and filtrate, the filtrate is alkaline solution and used in the alkaline leaching step .

Further, acid mill the filter residue after alkali leaching, add one or both of sulfuric acid or nitric acid for wet milling, control the pH of the acid solution to be ≤3, the liquid-solid ratio is 40:100, and grind until the average particle size is less than 14 μm, Then wash with water and dry to obtain the titanium silicon carrier. The filtrate needs to remove impurities after 3 times of vanadium and tungsten precipitation. The impurity removal method is to neutralize the acid solution after acid grinding and water washing with the alkaline filtrate after vanadium and tungsten precipitation, and then add excess Ca ions and a small amount of barium ions to remove sulfur and phosphorus. , arsenic and other impurities, filtered to obtain reusable water.

Implementation Case 18

A method for recovering waste denitrification catalysts to prepare titanium-silicon carriers, including pretreatment, alkali leaching, and filtration to obtain filtrate and filter residue, further precipitating vanadium, tungsten, and drying the filtrate to obtain calcium tungstate products, acid milling the filter residue, washing with water, and drying to obtain titanium Silicon carrier, as well as acid and alkali neutralization, impurity removal and reuse.

Pretreatment includes vacuuming, crushing and pre-grinding. The suction is set at 850mbar, crushed to 1-8mm, and pre-ground to an average particle size of 5-80μm to obtain spent denitrification catalyst powder. Further ammonia water alkali leaching, configure 3wt.% ammonia solution and waste denitrification catalyst powder into the stirring reactor according to the liquid-solid mass ratio of 100:40, set the alkali leaching temperature to 70°C, the alkali leaching pressure to 0.1MPa, and the alkali leaching time to 3h, the stirring speed is 50r/min, alkali leaching and filtration to obtain the filter residue and filtrate. After the filtrate is cooled to 20°C, add ammonia water to adjust the mass fraction of ammonia water to be greater than 9wt.%, filter and dry to obtain ammonium vanadate product; further add one or _both of CaO or Ca(OH) for precipitation, and the addition amount is 0.9 times of the total content of tungsten element, the precipitation reaction temperature is 30°C, the precipitation reaction time is 1.5 hours, the stirring speed is 50r/min, then filter and dry to obtain calcium tungstate and filtrate, the filtrate is alkaline solution and is used in the alkaline leaching step .

Further, acid mill the filter residue after alkali leaching, add one or both of sulfuric acid or nitric acid for wet milling, control the pH of the acid solution to be ≤3, the liquid-solid ratio is 50:100, and grind until the average particle size is less than 13 μm, Then wash with water and dry to obtain the titanium silicon carrier. The filtrate needs to remove impurities after vanadium and tungsten precipitation for 4 times. The impurity removal method is to neutralize the acid solution after acid grinding and water washing with the alkaline filtrate after vanadium and tungsten precipitation, and then add excess Ca ions and a small amount of barium ions to remove sulfur and phosphorus. , arsenic and other impurities, filtered to obtain reusable water.

Implementation Case 19

A method for recovering waste denitrification catalysts to prepare titanium-silicon carriers, including pretreatment, alkali leaching, and filtration to obtain filtrate and filter residue, further precipitating vanadium, tungsten, and drying the filtrate to obtain calcium tungstate products, acid milling the filter residue, washing with water, and drying to obtain titanium Silicon carrier, as well as acid and alkali neutralization, impurity removal and reuse.

Pretreatment includes vacuuming, crushing and pre-grinding. The suction is set at 800mbar, crushed to 1-7mm, and pre-ground to an average particle size of 5-70μm to obtain spent denitrification catalyst powder. Further ammonia water alkali leaching, configure 3.5wt.% ammonia solution and waste denitrification catalyst powder into the stirring reactor at a liquid-solid mass ratio of 100:35, set the alkali leaching temperature to 80°C, the alkali leaching pressure to 0.1MPa, and the alkali leaching time for 2.5h, the stirring speed is 60r/min, alkali leaching and filtration to obtain the filter residue and filtrate. After the filtrate is cooled to 20°C, add ammonia water to adjust the mass fraction of ammonia water to be greater than 9wt.%, filter and dry to obtain ammonium vanadate product; further add one or _both of CaO or Ca(OH) for precipitation, and the addition amount is 0.95 times of the total content of tungsten element, the precipitation reaction temperature is 35°C, the precipitation reaction time is 2 hours, the stirring speed is 60r/min, then filter and dry to obtain calcium tungstate and filtrate, the filtrate is alkaline solution and is used in the alkaline leaching step .

Further, acid mill the filter residue after alkali leaching, add one or both of sulfuric acid or nitric acid for wet milling, control the pH of the acid solution to be ≤3, the liquid-solid ratio is 60:100, and grind until the average particle size is less than 12 μm, Then wash with water and dry to obtain the titanium silicon carrier. The filtrate needs to remove impurities after vanadium and tungsten precipitation for 5 times. The impurity removal method is to neutralize the acid solution after acid grinding and water washing with the alkaline filtrate after vanadium and tungsten precipitation, and then add excess Ca ions and a small amount of barium ions to remove sulfur and phosphorus. , arsenic and other impurities, filtered to obtain reusable water.

Implementation Case 20

A method for recovering waste denitrification catalysts to prepare titanium-silicon carriers, including pretreatment, alkali leaching, and filtration to obtain filtrate and filter residue, further precipitating vanadium, tungsten, and drying the filtrate to obtain calcium tungstate products, acid milling the filter residue, washing with water, and drying to obtain titanium Silicon carrier, as well as acid and alkali neutralization, impurity removal and reuse.

Pretreatment includes vacuuming, crushing and pre-grinding. The suction is set at 750mbar, crushed to 1-6mm, and pre-ground to an average particle size of 5-60μm to obtain spent denitrification catalyst powder. Further ammonia water alkali leaching, configure 4wt.% ammonia solution and waste denitration catalyst powder into the stirring reactor according to the liquid-solid mass ratio of 100:30, set the alkali leaching temperature to 90°C, the alkali leaching pressure to 0.1MPa, and the alkali leaching time to 2h, the stirring speed is 70r/min, alkali leaching and filtration to obtain the filter residue and filtrate. After the filtrate is cooled to 20°C, add ammonia water to adjust the mass fraction of ammonia water to be greater than 9wt.%, filter and dry to obtain ammonium vanadate product; further add one or _both of CaO or Ca(OH) for precipitation, and the addition amount is 0.95 times the total content of tungsten element, the precipitation reaction temperature is 35°C, the precipitation reaction time is 1.5 hours, and the stirring speed is 70r/min, then filter and dry to obtain calcium tungstate and filtrate, and the filtrate is alkaline solution for alkaline leaching step .

Further, acid mill the filter residue after alkali leaching, add one or both of sulfuric acid or nitric acid for wet milling, control the pH of the acid solution to be ≤3, the liquid-solid ratio is 70:100, and grind until the average particle size is less than 11 μm, Then wash with water and dry to obtain the titanium silicon carrier. The filtrate needs to remove impurities after vanadium and tungsten precipitation for 5 times. The impurity removal method is to neutralize the acid solution after acid grinding and water washing with the alkaline filtrate after vanadium and tungsten precipitation, and then add excess Ca ions and a small amount of barium ions to remove sulfur and phosphorus. , arsenic and other impurities, filtered to obtain reusable water.

Implementation Case 21

A method for recovering waste denitrification catalysts to prepare titanium-silicon carriers, including pretreatment, alkali leaching, and filtration to obtain filtrate and filter residue, further precipitating vanadium, tungsten, and drying the filtrate to obtain calcium tungstate products, acid milling the filter residue, washing with water, and drying to obtain titanium Silicon carrier, as well as acid and alkali neutralization, impurity removal and reuse.

Pretreatment includes vacuuming, crushing and pre-grinding. The suction is set at 700mbar, crushed to 1-5mm, and pre-ground to an average particle size of 5-50μm to obtain spent denitrification catalyst powder. Further ammonia water alkaline leaching, configure 4.5wt.% ammonia solution and waste denitrification catalyst powder into the stirring reactor at a liquid-solid mass ratio of 100:25, set the alkali leaching temperature to 100°C, the alkali leaching pressure to 0.1MPa, and the alkali leaching time for 1.5h, the stirring speed was 80r/min, and the filter residue and filtrate were obtained by alkali leaching and filtration. After the filtrate is cooled to 25°C, add ammonia water to adjust the mass fraction of ammonia water to be greater than 9wt.%, filter and dry to obtain the ammonium vanadate product; further add one or _both of CaO or Ca(OH) for precipitation, and the addition amount is 0.95 times the total content of tungsten elements, the precipitation reaction temperature is 30°C, the precipitation reaction time is 2 hours, the stirring speed is 80r/min, then filtered and dried to obtain calcium tungstate and filtrate, the filtrate is alkaline solution and used in the alkaline leaching step .

Further, acid mill the filter residue after alkali leaching, add one or both of sulfuric acid or nitric acid for wet milling, control the pH of the acid solution to be ≤3, the liquid-solid ratio is 80:100, and grind until the average particle size is less than 10 μm, Then wash with water and dry to obtain the titanium silicon carrier. The filtrate needs to remove impurities after vanadium and tungsten precipitation for 5 times. The impurity removal method is to neutralize the acid solution after acid grinding and water washing with the alkaline filtrate after vanadium and tungsten precipitation, and then add excess Ca ions and a small amount of barium ions to remove sulfur and phosphorus. , arsenic and other impurities, filtered to obtain reusable water.

Implementation Case 22

A method for recovering waste denitrification catalysts to prepare titanium-silicon carriers, including pretreatment, alkali leaching, and filtration to obtain filtrate and filter residue, further precipitating vanadium, tungsten, and drying the filtrate to obtain calcium tungstate products, acid milling the filter residue, washing with water, and drying to obtain titanium Silicon carrier, as well as acid and alkali neutralization, impurity removal and reuse.

Pretreatment includes vacuuming, crushing and pre-grinding. The suction is set at 650mbar, crushed to 1-4mm, and pre-ground to an average particle size of 5-40μm to obtain spent denitrification catalyst powder. Further ammonia water alkaline leaching, configure 5.5wt.% ammonia solution and waste denitrification catalyst powder into the stirring reactor according to the liquid-solid mass ratio of 100:20, set the alkali leaching temperature to 110°C, the alkali leaching pressure to 0.15MPa, and the alkali leaching time for 1 h, stirring at a speed of 90 r/min, alkali leaching and filtration to obtain the filter residue and filtrate. After the filtrate is cooled to 25°C, add ammonia water to adjust the mass fraction of ammonia water to be greater than 9wt.%, filter and dry to obtain the ammonium vanadate product; further add one or _both of CaO or Ca(OH) for precipitation, and the addition amount is 0.95 times the total content of tungsten elements, the precipitation reaction temperature is 25°C, the precipitation reaction time is 0.5 hours, the stirring speed is 90r/min, then filtered and dried to obtain calcium tungstate and filtrate, the filtrate is alkaline solution and used in the alkaline leaching step .

Further, acid mill the filter residue after alkali leaching, add one or both of sulfuric acid or nitric acid for wet milling, control the pH of the acid solution to ≤3, the liquid-solid ratio is 75:100, and grind until the average particle size is less than 9 μm, Then wash with water and dry to obtain the titanium silicon carrier. The filtrate needs to remove impurities after vanadium and tungsten precipitation for 4 times. The impurity removal method is to neutralize the acid solution after acid grinding and water washing with the alkaline filtrate after vanadium and tungsten precipitation, and then add excess Ca ions and a small amount of barium ions to remove sulfur and phosphorus. , arsenic and other impurities, filtered to obtain reusable water.

Implementation Case 23

A method for recovering waste denitrification catalysts to prepare titanium-silicon carriers, including pretreatment, alkali leaching, and filtration to obtain filtrate and filter residue, further precipitating vanadium, tungsten, and drying the filtrate to obtain calcium tungstate products, acid milling the filter residue, washing with water, and drying to obtain titanium Silicon carrier, as well as acid and alkali neutralization, impurity removal and reuse.

Pretreatment includes vacuuming, crushing and pre-grinding. The suction is set at 600mbar, crushed to 1-3mm, and pre-ground to an average particle size of 5-30μm to obtain spent denitrification catalyst powder. For further ammonia leaching, configure 6.5wt.% ammonia solution and waste denitrification catalyst powder into the stirring reactor at a liquid-solid mass ratio of 100:50, set the alkali leaching temperature to 120°C, the alkali leaching pressure to 0.2MPa, and the alkali leaching time 0.5h, the stirring speed is 100r/min, alkali leaching and filtration to obtain the filter residue and filtrate. After the filtrate is cooled to 30°C, add ammonia water to adjust the mass fraction of ammonia water to be greater than 9wt.%, filter and dry to obtain ammonium vanadate product; further add one or _both of CaO or Ca(OH) for precipitation, and the addition amount is 1 times the total content of tungsten elements, the precipitation reaction temperature is 25°C, the precipitation reaction time is 0.5 hours, the stirring speed is 100r/min, then filtered and dried to obtain calcium tungstate and filtrate, the filtrate is alkaline solution and used in the alkaline leaching step .

Further, acid mill the filter residue after alkali leaching, add one or both of sulfuric acid or nitric acid for wet milling, control the pH of the acid solution to be ≤3, the liquid-solid ratio is 65:100, and grind until the average particle size is less than 10 μm, Then wash with water and dry to obtain the titanium silicon carrier. The filtrate needs to remove impurities after 3 times of vanadium and tungsten precipitation. The impurity removal method is to neutralize the acid solution after acid grinding and water washing with the alkaline filtrate after vanadium and tungsten precipitation, and then add excess Ca ions and a small amount of barium ions to remove sulfur and phosphorus. , arsenic and other impurities, filtered to obtain reusable water.

Implementation Case 24

A method for recovering waste denitrification catalysts to prepare titanium-silicon carriers, including pretreatment, alkali leaching, and filtration to obtain filtrate and filter residue, further precipitating vanadium, tungsten, and drying the filtrate to obtain calcium tungstate products, acid milling the filter residue, washing with water, and drying to obtain titanium Silicon carrier, as well as acid and alkali neutralization, impurity removal and reuse.

Pretreatment includes vacuuming, crushing and pre-grinding. The suction is set at 550mbar, crushed to 1-3mm, and pre-ground to an average particle size of 5-30μm to obtain spent denitrification catalyst powder. Further ammonia water alkaline leaching, configure 7.5wt.% ammonia solution and waste denitrification catalyst powder into the stirring reactor according to the liquid-solid mass ratio of 100:45, set the alkali leaching temperature to 130°C, the alkali leaching pressure to 0.3MPa, and the alkali leaching time for 1 h, stirring at a speed of 110 r/min, alkali leaching and filtration to obtain filter residue and filtrate. After the filtrate is cooled to 25°C, add ammonia water to adjust the mass fraction of ammonia water to be greater than 9wt.%, filter and dry to obtain the ammonium vanadate product; further add one or _both of CaO or Ca(OH) for precipitation, and the addition amount is 1 times the total content of tungsten element, the precipitation reaction temperature is 25°C, the precipitation reaction time is 1 hour, and the stirring speed is 110r/min, then filter and dry to obtain calcium tungstate and filtrate, and the filtrate is alkaline solution for alkaline leaching step .

Further, acid mill the filter residue after alkali leaching, add one or both of sulfuric acid or nitric acid for wet milling, control the pH of the acid solution to be ≤3, the liquid-solid ratio is 55:100, and grind until the average particle size is less than 11 μm, Then wash with water and dry to obtain the titanium silicon carrier. The filtrate needs to remove impurities after 3 times of vanadium and tungsten precipitation. The impurity removal method is to neutralize the acid solution after acid grinding and water washing with the alkaline filtrate after vanadium and tungsten precipitation, and then add excess Ca ions and a small amount of barium ions to remove sulfur and phosphorus. , arsenic and other impurities, filtered to obtain reusable water.

Implementation Case 25

A method for recovering waste denitrification catalysts to prepare titanium-silicon carriers, including pretreatment, alkali leaching, and filtration to obtain filtrate and filter residue, further precipitating vanadium, tungsten, and drying the filtrate to obtain calcium tungstate products, acid milling the filter residue, washing with water, and drying to obtain titanium Silicon carrier, as well as acid and alkali neutralization, impurity removal and reuse.

Pretreatment includes vacuuming, crushing and pre-grinding. The suction is set at 500mbar, crushed to 1-4mm, and pre-ground to an average particle size of 5-45μm to obtain spent denitrification catalyst powder. Further ammonia water alkaline leaching, configure 8.5wt.% ammonia solution and waste denitrification catalyst powder into the stirring reactor according to the liquid-solid mass ratio of 100:35, set the alkali leaching temperature to 125°C, the alkali leaching pressure to 0.25MPa, and the alkali leaching time for 1.5h, the stirring speed was 120r/min, and the filter residue and filtrate were obtained by alkali leaching and filtration. After the filtrate is cooled to 40°C, add ammonia water to adjust the mass fraction of ammonia water to be greater than 9wt.%, filter and dry to obtain ammonium vanadate product; further add one or _both of CaO or Ca(OH) for precipitation, and the addition amount is 1.0 times the total content of tungsten elements, the precipitation reaction temperature is 20°C, the precipitation reaction time is 1.5 hours, and the stirring speed is 120r/min, then filter and dry to obtain calcium tungstate and filtrate, and the filtrate is alkaline solution for alkaline leaching step .

Further, acid mill the filter residue after alkali leaching, add one or both of sulfuric acid or nitric acid for wet milling, control the pH of the acid solution to ≤3, the liquid-solid ratio is 45:100, and grind until the average particle size is less than 12 μm, Then wash with water and dry to obtain the titanium silicon carrier. The filtrate needs to remove impurities after 3 times of vanadium and tungsten precipitation. The impurity removal method is to neutralize the acid solution after acid grinding and water washing with the alkaline filtrate after vanadium and tungsten precipitation, and then add excess Ca ions and a small amount of barium ions to remove sulfur and phosphorus. , arsenic and other impurities, filtered to obtain reusable water.

Implementation Case 26

A method for recovering waste denitrification catalysts to prepare titanium-silicon carriers, including pretreatment, alkali leaching, and filtration to obtain filtrate and filter residue, further precipitating vanadium, tungsten, and drying the filtrate to obtain calcium tungstate products, acid milling the filter residue, washing with water, and drying to obtain titanium Silicon carrier, as well as acid and alkali neutralization, impurity removal and reuse.

Pretreatment includes vacuuming, crushing and pre-grinding. The suction is set at 450mbar, crushed to 1-6mm, and pre-ground to an average particle size of 5-55μm to obtain spent denitrification catalyst powder. Further ammonia water alkali leaching, configure 9wt.% ammonia solution and waste denitration catalyst powder into the stirring reactor according to the liquid-solid mass ratio of 100:50, set the alkali leaching temperature to 115°C, the alkali leaching pressure to 0.2MPa, and the alkali leaching time to 2h, the stirring speed is 110r/min, alkali leaching and filtration to obtain the filter residue and filtrate. After the filtrate is cooled to 35°C, add ammonia water to adjust the mass fraction of ammonia water to be greater than 9wt.%, filter and dry to obtain the ammonium vanadate product; further add one or _both of CaO or Ca(OH) for precipitation, and the addition amount is 1 times the total content of tungsten element, the precipitation reaction temperature is 25°C, the precipitation reaction time is 2 hours, the stirring speed is 110r/min, then filter and dry to obtain calcium tungstate and filtrate, and the filtrate is alkaline solution for alkaline leaching step .

Further, acid mill the filter residue after alkali leaching, add one or both of sulfuric acid or nitric acid for wet milling, control the pH of the acid solution to be ≤3, the liquid-solid ratio is 40:100, and grind until the average particle size is less than 13 μm, Then wash with water and dry to obtain the titanium silicon carrier. The filtrate needs to remove impurities after vanadium and tungsten precipitation for 4 times. The impurity removal method is to neutralize the acid solution after acid grinding and water washing with the alkaline filtrate after vanadium and tungsten precipitation, and then add excess Ca ions and a small amount of barium ions to remove sulfur and phosphorus. , arsenic and other impurities, filtered to obtain reusable water.

Implementation Case 27

A method for recovering waste denitrification catalysts to prepare titanium-silicon carriers, including pretreatment, alkali leaching, and filtration to obtain filtrate and filter residue, further precipitating vanadium, tungsten, and drying the filtrate to obtain calcium tungstate products, acid milling the filter residue, washing with water, and drying to obtain titanium Silicon carrier, as well as acid and alkali neutralization, impurity removal and reuse.

Pretreatment includes vacuuming, crushing and pre-grinding. The suction is set at 400mbar, crushed to 1-7mm, and pre-ground to an average particle size of 5-65μm to obtain spent denitrification catalyst powder. Further ammonia water alkaline leaching, configure 9.5wt.% ammonia solution and waste denitrification catalyst powder into the stirring reactor according to the liquid-solid mass ratio of 100:50, set the alkali leaching temperature to 105°C, the alkali leaching pressure to 0.15MPa, and the alkali leaching time for 2.5 hours, with a stirring speed of 100r/min, alkali leaching and filtration to obtain filter residue and filtrate. After the filtrate is cooled to 35°C, add ammonia water to adjust the mass fraction of ammonia water to be greater than 9wt.%, filter and dry to obtain the ammonium vanadate product; further add one or _both of CaO or Ca(OH) for precipitation, and the addition amount is 0.95 times of the total content of tungsten element, the precipitation reaction temperature is 20°C, the precipitation reaction time is 2 hours, the stirring speed is 100r/min, then filter and dry to obtain calcium tungstate and filtrate, the filtrate is alkaline solution and is used in the alkaline leaching step .

Further, acid mill the filter residue after alkali leaching, add one or both of sulfuric acid or nitric acid for wet milling, control the pH of the acid solution to be ≤3, the liquid-solid ratio is 30:100, and grind until the average particle size is less than 15 μm, Then wash with water and dry to obtain the titanium silicon carrier. The filtrate needs to remove impurities after vanadium and tungsten precipitation for 4 times. The impurity removal method is to neutralize the acid solution after acid grinding and water washing with the alkaline filtrate after vanadium and tungsten precipitation, and then add excess Ca ions and a small amount of barium ions to remove sulfur and phosphorus. , arsenic and other impurities, filtered to obtain reusable water.

Implementation Case 28

A method for recovering waste denitrification catalysts to prepare titanium-silicon carriers, including pretreatment, alkali leaching, and filtration to obtain filtrate and filter residue, further precipitating vanadium, tungsten, and drying the filtrate to obtain calcium tungstate products, acid milling the filter residue, washing with water, and drying to obtain titanium Silicon carrier, as well as acid and alkali neutralization, impurity removal and reuse.

Pretreatment includes vacuuming, crushing and pre-grinding. The suction is set at 350mbar, crushed to 1-8mm, and pre-ground to an average particle size of 5-75μm to obtain spent denitrification catalyst powder. Further ammonia water alkali leaching, configure 7wt.% ammonia solution and waste denitrification catalyst powder into the stirring reactor according to the liquid-solid mass ratio of 100:40, set the alkali leaching temperature to 95°C, the alkali leaching pressure to 0.1MPa, and the alkali leaching time to 3h, the stirring speed is 90r/min, alkali leaching and filtration to obtain the filter residue and filtrate. After the filtrate is cooled to 30°C, add ammonia water to adjust the mass fraction of ammonia water to be greater than 9wt.%, filter and dry to obtain ammonium vanadate product; further add one or _both of CaO or Ca(OH) for precipitation, and the addition amount is 1 times the total content of tungsten element, the precipitation reaction temperature is 25°C, the precipitation reaction time is 0.5 hours, the stirring speed is 35r/min, then filter and dry to obtain calcium tungstate and filtrate, the filtrate is alkaline solution and used in the alkaline leaching step .

Further, acid mill the filter residue after alkali leaching, add one or both of sulfuric acid or nitric acid for wet milling, control the pH of the acid solution to be ≤3, the liquid-solid ratio is 35:100, and grind until the average particle size is less than 7 μm, Then wash with water and dry to obtain the titanium silicon carrier. The filtrate needs to remove impurities after vanadium and tungsten precipitation twice. The impurity removal method is to neutralize the acid solution after acid grinding and water washing with the alkaline filtrate after vanadium and tungsten precipitation, and then add excess Ca ions and a small amount of barium ions to remove sulfur and phosphorus. , arsenic and other impurities, filtered to obtain reusable water.

Implementation Case 29

A method for recovering waste denitrification catalysts to prepare titanium-silicon carriers, including pretreatment, alkali leaching, and filtration to obtain filtrate and filter residue, further precipitating vanadium, tungsten, and drying the filtrate to obtain calcium tungstate products, acid milling the filter residue, washing with water, and drying to obtain titanium Silicon carrier, as well as acid and alkali neutralization, impurity removal and reuse.

Pretreatment includes vacuuming, crushing and pre-grinding. The suction is set at 300mbar, crushed to 1-9mm, and pre-ground to an average particle size of 5-85μm to obtain spent denitrification catalyst powder. Further ammonia water alkali leaching, configure 6wt.% ammonia solution and waste denitration catalyst powder into the stirring reactor according to the liquid-solid mass ratio of 100:30, set the alkali leaching temperature to 85°C, the alkali leaching pressure to 0.1MPa, and the alkali leaching time to 3.5h, the stirring speed is 80r/min, alkali leaching and filtration to obtain the filter residue and filtrate. After the filtrate is cooled to 25°C, add ammonia water to adjust the mass fraction of ammonia water to be greater than 9wt.%, filter and dry to obtain the ammonium vanadate product; further add one or _both of CaO or Ca(OH) for precipitation, and the addition amount is 0.95 times of the total content of tungsten elements, the precipitation reaction temperature is 25°C, the precipitation reaction time is 2 hours, the stirring speed is 55r/min, then filtered and dried to obtain calcium tungstate and filtrate, the filtrate is alkaline solution and used in the alkaline leaching step .

Further, acid mill the filter residue after alkali leaching, add one or both of sulfuric acid or nitric acid for wet milling, control the pH of the acid solution to be ≤3, the liquid-solid ratio is 45:100, and grind until the average particle size is less than 8 μm, Then wash with water and dry to obtain the titanium silicon carrier. The filtrate needs to remove impurities after 3 times of vanadium and tungsten precipitation. The impurity removal method is to neutralize the acid solution after acid grinding and water washing with the alkaline filtrate after vanadium and tungsten precipitation, and then add excess Ca ions and a small amount of barium ions to remove sulfur and phosphorus. , arsenic and other impurities, filtered to obtain reusable water.

Implementation Case 30

A method for recovering waste denitrification catalysts to prepare titanium-silicon carriers, including pretreatment, alkali leaching, and filtration to obtain filtrate and filter residue, further precipitating vanadium, tungsten, and drying the filtrate to obtain calcium tungstate products, acid milling the filter residue, washing with water, and drying to obtain titanium Silicon carrier, as well as acid and alkali neutralization, impurity removal and reuse.

Pretreatment includes vacuuming, crushing and pre-grinding. The suction is set at 300mbar, crushed to 1-10mm, and pre-ground to an average particle size of 5-95μm to obtain spent denitrification catalyst powder. Further ammonia water alkali leaching, configure 10wt.% ammonia solution and waste denitrification catalyst powder into the stirring reactor according to the liquid-solid mass ratio of 100:20, set the alkali leaching temperature to 130°C, the alkali leaching pressure to 0.3MPa, and the alkali leaching time to 0.5h, the stirring speed is 70r/min, alkali leaching and filtration to obtain the filter residue and filtrate. After the filtrate is cooled to 20°C, add ammonia water to adjust the mass fraction of ammonia water to be greater than 9wt.%, filter and dry to obtain ammonium vanadate product; further add one or _both of CaO or Ca(OH) for precipitation, and the addition amount is 0.9 times of the total content of tungsten elements, the precipitation reaction temperature is 25°C, the precipitation reaction time is 2 hours, the stirring speed is 120r/min, then filter and dry to obtain calcium tungstate and filtrate, the filtrate is alkaline solution and is used in the alkaline leaching step .

Further, acid mill the filter residue after alkali leaching, add one or both of sulfuric acid or nitric acid for wet milling, control the pH of the acid solution to be ≤3, the liquid-solid ratio is 55:100, and grind until the average particle size is less than 9 μm, Then wash with water and dry to obtain the titanium silicon carrier. The filtrate needs to remove impurities after vanadium and tungsten precipitation for 4 times. The impurity removal method is to neutralize the acid solution after acid grinding and water washing with the alkaline filtrate after vanadium and tungsten precipitation, and then add excess Ca ions and a small amount of barium ions to remove sulfur and phosphorus. , arsenic and other impurities, filtered to obtain reusable water.

Claims (5)

1. A method for recovering and preparing a titanium-silicon carrier from a waste denitrification catalyst, characterized in that it comprises pretreatment, alkali leaching, and filtration to obtain filtrate and filter residue steps, further filtrate sinking vanadium, sinking tungsten, drying to obtain calcium tungstate products, filter residue acid Grinding, washing, and drying to obtain titanium-silicon carrier, as well as acid and alkali neutralization, impurity removal and reuse; The pretreatment includes dust suction, crushing and pre-grinding; the dust suction is to absorb the floating dust on the surface of the waste denitration catalyst, and the suction force is set to 300-980mbar; the crushing mechanically crushes the waste denitration catalyst after dust suction to 1-10mm; The pre-grinding is to grind the crushed waste denitration catalyst to an average particle size of 5-100 μm to obtain waste denitration catalyst powder; Described alkali leaching is divided into caustic soda alkali leaching and ammonia water alkali leaching two kinds; The caustic soda leaching is specifically configured by adding 0.5-9wt.% NaOH solution and waste denitration catalyst powder into the stirring reactor according to the liquid-solid mass ratio of 100:(20-50), and setting the alkali leaching temperature to 40-100°C, Alkali leaching time is 0.5-4h, stirring speed is 30-120r/min; The ammonia water alkali leaching is specifically configured by adding 2-10wt.% ammonia solution and waste denitrification catalyst powder into the stirring reactor at a liquid-solid mass ratio of 100:(20-50), and setting the alkali leaching temperature to 50-130°C. The alkali leaching pressure is 0.1-0.3MPa, the alkali leaching time is 0.5-4h, and the stirring speed is 30-120r/min; The acid milling of the filter residue is wet grinding by adding one or both of sulfuric acid or nitric acid, controlling the pH of the acid solution to be ≤3, the liquid-solid ratio is (30-80):100, and grinding to an average particle size of less than 15 μm. 2. A kind of waste denitrification catalyst according to claim 1 reclaims and prepares the method for titanium-silicon carrier, it is characterized in that, the method for sinking vanadium and tungsten in the caustic soda leaching mode filtrate is: add CaO or Ca(OH) in _a kind of Or two kinds of precipitation, the addition amount is 0.9-1.0 times of the total content of vanadium and tungsten elements, the precipitation reaction temperature is 20-35°C, the precipitation reaction time is 1.5-4 hours, the stirring speed is 30-120r/min, and then filtered and drying to obtain a vanadium-tungsten product and a filtrate with calcium tungstate as the main product, and the filtrate is alkali liquor and is reused in the alkali leaching step. 3. According to claim 1, a method for recovering and preparing a titanium-silicon carrier from a waste denitrification catalyst is characterized in that, the method of sinking vanadium and tungsten in the filtrate in the way of ammonia water alkali leaching is as follows: after the filtrate is cooled to 20-40°C, add ammonia water to adjust Until the mass fraction of ammonia water is greater than 9wt.%, filter and dry to obtain the ammonium vanadate product; further add one or both of CaO or Ca(OH) for _{precipitation} , and the amount added is 0.9-1.0 times the total content of tungsten elements, The precipitation reaction temperature is 20-35°C, the precipitation reaction time is 0.5-2 hours, and the stirring speed is 30-120r/min, and then filtered and dried to obtain calcium tungstate and filtrate, and the filtrate is alkaline solution to be used in the alkaline leaching step. 4. A method for preparing a titanium-silicon carrier by recovering a waste denitration catalyst according to claim 1, wherein the water washing is acid milling followed by washing with clean water to remove impurities, and further drying to obtain a titanium-silicon carrier. 5. according to claim 1, a kind of waste denitrification catalyst reclaims and prepares the method for titanium-silicon carrier, it is characterized in that, after the filtrate sinks vanadium and sinks tungsten for 2-5 times, it needs to remove impurities, and the method of removing impurities is washing the acid mill with water. The acid solution is neutralized with the alkaline filtrate after precipitation of vanadium and tungsten, then excess Ca ions and a small amount of barium ions are added to remove sulfur, phosphorus, and arsenic impurities, and the reusable water is obtained by filtration.

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