CN101709390B - An online circulation method for vanadium extraction process from stone coal - Google Patents

Abstract

The invention relates to an on-line circulation method for a process for extracting vanadium from stone coal. The technical scheme of the method comprises that: the process for extracting the vanadium, which comprises the steps of decarbonizing, performing sodium treatment and roasting, water leaching, acid leaching, ion resin exchange, precipitating vanadium in acid ammonium salt, deaminizing and calcining, is adopted for the crude ore of the stone coal of which the vanadium pentoxide content is more than or equal to 0.7 percent. The process for extracting the vanadium comprises the following steps: performing primary spray on acid smoke with lower adsorption solution to form acid solution for acid leaching process; performing neutralization treatment on the acid leaching solution to obtain enriched vanadium slag and treatment solution, and performing sodium treatment and roasting on the enriched vanadium slag; performing blowoff treatment on the vanadium precipitating mother solution to produce ammonia and alkaline treatment solution; spraying the ammonia with solution of hydrochloric acid to produce ammonium chloride, and precipitating the vanadium in ammonium chloride; performing secondary spray on the acid smoke after the primary spray with the alkaline treatment solution, and water leaching the formed lower spray solution. The circulation method enables the gas, wastewater, slag and the like produced in the process for extracting the vanadium to be not only treated, but also converted into intermediate products required in the technological process for recycling, so that production cost is reduced and the effects of energy conservation and emission reduction are obvious.

Description

An online circulation method for vanadium extraction process from stone coal

technical field

The invention belongs to the technical field of vanadium extraction from stone coal. In particular, it relates to an online circulation method used in the process of extracting vanadium from stone coal.

Background technique

Stone coal is a unique and important vanadium resource in my country. Vanadium in stone coal mainly exists in the low-valence state in mica and other mineral lattices. To extract vanadium from stone coal, vanadium must be dissociated from the mica phase. The most effective way to destroy the vanadium-containing mica lattice structure in stone coal is high-temperature oxidation roasting. The existing vanadium extraction process from stone coal is mostly "decarburization-sodium roasting-water leaching-acid leaching-ion resin exchange-acid ammonium salt Vanadium Precipitation - Deamination Calcination", although the vanadium extraction process is simple to operate, a large amount of waste gas, waste water and waste residue are also produced in the process: sodium roasting produces acid gas, which contains HCl, Cl ₂ , SO ₂ ; deammonization calcining And blow off the vanadium precipitation mother liquor to produce ammonia gas, these gases need to be treated before they can be discharged; the wastewater generated in the process is the adsorption liquid formed after the water immersion solution is absorbed by the ion resin, and the vanadium precipitation mother liquor after the ammonium salt vanadium precipitation ; Although the adsorbed liquid can be directly discharged, it will also waste precious water resources; the pH value of the vanadium precipitation mother liquid is about 3 and contains 8000-10000 mg/L NH ₄ ⁺ , and it needs to be treated before it can reach the discharge standard; acid leaching liquid It also needs to be processed before the vanadium in it can be recovered. Today, with increasing emphasis on environmental protection and advocating energy conservation and emission reduction, the waste gas, waste water and corresponding slag generated in the process need to be treated reasonably to meet the corresponding emission standards. For this reason, it has attracted the attention of scientific and technical personnel:

"Exhaust gas treatment method for producing vanadium pentoxide by sodium roasting method" (CN101322907A) patent technology discloses a waste gas treatment method for producing vanadium pentoxide by sodium roasting method, using three multifunctional towers and multiple circulating pools Composed of circulation system to eliminate exhaust gas.

"Exhaust gas treatment and comprehensive utilization technology in the production of vanadium pentoxide" (CN100998931A) patent technology discloses a production waste gas treatment and comprehensive utilization technology of vanadium pentoxide. Adopt three-step treatment of waste gas cooling, lime milk spray neutralization, quicklime particle filtration, absorption and dehumidification, the condensate produced by waste gas cooling treatment and the lime milk clarified liquid after lime milk spray treatment, through adjusting the pH value and evaporation, concentration, crystallization, and drying Dehydration to produce calcium chloride.

"A Process for Treating Acidic Vanadium Precipitation Wastewater" (CN1406882A) patent technology discloses a process for treating acidic vanadium precipitation wastewater. Specifically, chromium is removed first, and then ammonia is removed, so that both chromium and ammonia in the tail water discharged at the end can meet the emission standards.

"A method for purifying flue gas from sodium roasting of vanadium-containing stone coal" (CN101069807A) patent technology discloses a method for purifying flue gas from sodium roasting of vanadium-containing stone coal. In this method, lime milk or limestone milk is used as a roasting flue gas purifier, after absorbing HCl and other acidic gases, it is filtered, and the filtrate is added with acid or alkali to adjust the pH value, and then sodium sulfate is added for secondary filtration to obtain gypsum and sodium chloride solution. .

However, the above-mentioned technical methods are only for the treatment of one of the "three wastes" in the process of vanadium extraction from stone coal, and their purpose is to discharge the "three wastes" harmlessly, or to obtain some other industrial by-products during the treatment process Instead of comprehensively utilizing the active ingredients in the "three wastes", it is impossible to realize the recycling of the intermediate products required in the process of converting the "three wastes" into vanadium extraction.

Contents of the invention

The invention aims to overcome the defects of the existing technology, and aims to provide an online circulation method for vanadium extraction from stone coal, which has simple process, reasonable process, environment-friendly, energy saving and emission reduction, and can reduce production cost.

In order to achieve the above object, the present invention is based on the vanadium extraction process of the existing stone coal raw ore through "decarburization-sodium roasting-water leaching-acid leaching-ion resin exchange-acidic ammonium salt vanadium precipitation-deammoniation calcination", The technical solutions adopted are:

(1) The acidic flue gas produced in the sodium roasting process is sprayed with the adsorption liquid produced in the ion resin exchange process, and the acidic solution formed by the primary spray is returned to the acid leaching process.

(2) Neutralize the acid leaching solution obtained in the acid leaching process to obtain a vanadium-rich slag and a treatment solution; return the vanadium-rich slag to the sodium roasting process, and discharge the treatment solution up to the standard.

(3) The vanadium precipitation mother liquor produced in the acidic ammonium salt vanadium precipitation process is stripped to produce ammonia and alkaline treatment liquid, and the ammonia gas produced in the stripping process and the ammonia gas produced in the deamination and calcination process are sprayed with hydrochloric acid solution to produce chlorine Ammonium chloride and ammonium chloride return to the acidic ammonium salt vanadium precipitation process; the alkaline treatment liquid performs secondary spraying on the acidic flue gas that has been sprayed in the primary level, and the flue gas is discharged after the secondary spraying, and the formed spray liquid Return to the flooding process.

The vanadium pentoxide grade of the raw stone coal ore is ≥0.7%.

The neutralization treatment is: first preheating the low-concentration vanadium-containing acid leaching solution obtained by acid leaching with a vanadium pentoxide concentration of 100-300mg/l to 20-45°C, and then setting the ratio of n _V :n _Fe =1:1~1:3 Add FeSO ₄ ·7H ₂ O to the pickling solution, then adjust to pH=4~6, react at 45~60°C for 10~30min, and finally pass solid-liquid The vanadium-rich slag and treatment liquid are separated.

Due to the adoption of the above technical scheme, the present invention is based on the vanadium extraction process of the existing stone coal raw ore through "decarburization-sodium roasting-water leaching-acid leaching-ion resin exchange-acidic ammonium salt vanadium precipitation-deammoniation calcination" , using online circulation technology, that is, according to the characteristics of the existing vanadium extraction process, the waste gas and waste water generated, such as adsorption liquid, acid flue gas, ammonia gas, acid leaching solution and vanadium precipitation mother liquor, etc. are comprehensively utilized and treated. Make it into intermediate products that can be used in the process, such as acid solution, vanadium-rich slag, ammonium chloride, etc., which can be recycled in the vanadium extraction process. Its characteristics are:

1. The lower liquid adsorbed in the ion resin exchange process is a neutral solution containing certain impurity ions. This solution is used for primary spraying of the acidic flue gas generated by sodium roasting, and the temperature is about 300 ° C. After the acid flue gas is sprayed through the first stage, an acidic solution with a temperature of about 40°C and a concentration of about 5% is formed for the acid leaching process in the vanadium extraction process. The above process converts the acid gas produced by the adsorption lower liquid and sodium roasting into the acidic solution required for the acid leaching process, which not only reduces the consumption of newly added acid in the acidic process, but also treats the flue gas and recycles the adsorption lower liquid .

2. After the acidic ammonium salt vanadium precipitation process, ammonium polyvanadate and vanadium precipitation mother liquor are produced. The temperature of the vanadium precipitation mother liquor is about 80°C, which contains 8000-10000 mg/L NH ₄ ⁺ . The vanadium precipitation mother liquor is injected into the ammonia gas blowing In the removal device, add milk of lime to adjust the pH value to above 11, blow off the ammonia gas, and make the ammonia gas enter the ammonia gas spray tower. The ammonia gas produced by the decomposition of ammonium polyvanadate to prepare vanadium pentoxide also enters the ammonia gas spray tower, and is sprayed with hydrochloric acid solution together with the ammonia gas produced by blowing off the vanadium precipitation mother liquor. Ammonium chloride returns to the acidic ammonium salt vanadium precipitation process.

3. The V ₂ O ₅ concentration produced in the acid leaching process is about 100-300mg/L acid leaching solution, and neutralization treatment: first preheat the acid leaching solution to 20-45°C, and then set the ratio of substances to n _V : n _Fe =1:1~1:3 Add FeSO ₄ ·7H ₂ O to the pickling solution, then adjust to pH=4~6, react at 45~60°C for 10~30min, and finally solidify The vanadium-rich slag and treatment liquid are separated from the liquid; the vanadium-rich slag is returned to the sodium roasting process, which not only improves the grade of the raw stone coal ore, but also promotes the oxidation of low-priced vanadium in the process of sodium roasting, so that the vanadium in the acid leaching solution It is recovered by water immersion, which significantly improves the efficiency of vanadium extraction; the treatment liquid can be directly discharged.

Therefore, the present invention forms acidic solution, vanadium-rich slag, and chlorine Intermediate products such as ammonium chloride can be reused in the vanadium extraction process. Therefore the present invention:

1) The process is simple, the process is reasonable, the production cost is reduced, and the economic benefit is improved;

2) Transform the "three wastes" into intermediate products required in the process, truly turning waste into treasure;

3) Environmentally friendly, energy-saving and emission-reducing effects are remarkable.

Description of drawings

Fig. 1 is a kind of process flow chart of the present invention.

Detailed ways

Below in conjunction with accompanying drawing and specific embodiment the present invention will be further described:

An on-line circulation method for vanadium extraction process from stone coal: this method adopts on-line circulation technology on the basis of the existing vanadium extraction process from stone coal. The existing stone coal vanadium extraction process flow is shown in the dotted line of the block diagram in Figure 1: after the stone coal raw ore with a vanadium pentoxide grade ≥ 0.7% is treated by decarburization, sodium roasting and water leaching, water leaching occurs. Liquid and water leaching residue, acidic flue gas is produced during sodium roasting; the water immersion liquid is exchanged with ion resin to obtain vanadium-rich liquid and adsorption lower liquid, and the vanadium-rich liquid is polyammonium vanadate and precipitated by acidic ammonium salt vanadium precipitation process. The vanadium mother liquor and ammonium polyvanadate are deaminated and calcined to obtain V ₂ O ₅ products and ammonia gas is produced at the same time; the water leaching slag is subjected to acid leaching treatment to obtain acid leaching liquid and slag.

On the basis of this process, the process flow adopted in this embodiment is shown in the solid line part of the block diagram in Figure 1:

(1) Use the adsorption liquid produced in the ion resin exchange process to spray the acidic fume at about 300 °C generated in the sodium roasting process, and the temperature formed by the first level spray is about 40 °C and the concentration is about 5 % of the acidic solution is returned to the acid leaching process.

(2) Neutralize the acid leaching solution obtained in the acid leaching process with a V ₂ O ₅ concentration of 100-300 mg/L, that is, preheat the acid leaching solution to 20-45°C, and then set the ratio of substances to n _V : n _Fe =1:1~1:3 Add FeSO ₄ ·7H ₂ O to the pickling solution, then adjust to pH=4~6, react at 45~60°C for 10~30min, and finally solidify The vanadium-rich slag and treatment solution are separated from the liquid; the vanadium-rich slag is returned to the sodium roasting process and then undergoes water leaching and acid leaching processes.

(3) The temperature of the vanadium precipitation mother liquor produced in the acidic ammonium salt vanadium precipitation process is about 80°C and contains 8000-10000 mg/L NH ₄ ⁺ . The vanadium precipitation mother liquor is injected into the ammonia gas stripping device, and the pH value is adjusted by adding milk of lime to Above 11, ammonia gas and alkaline treatment liquid are produced after stripping treatment, and the ammonia gas enters the ammonia gas spray tower; it is produced by the decomposition of ammonium polyvanadate when it is deaminated and calcined into V ₂ O ₅ products at 550-600 °C Ammonia also enters the ammonia spray tower. Then the ammonia gas obtained by blowing off and the ammonia gas produced in the deammonization and calcination process are sprayed with hydrochloric acid solution to produce ammonium chloride, and the ammonium chloride is returned to the acidic ammonium salt precipitation process; The acidic flue gas is subjected to secondary spraying, and the flue gas is discharged after the secondary spraying, and the formed spray liquid is returned to the water immersion process.

According to the self characteristics of the existing vanadium extraction process, this specific embodiment will comprehensively utilize and treat the waste gas and waste water produced, such as adsorption lower liquid, acid flue gas, ammonia gas, acid leaching solution and vanadium precipitation mother liquor, etc., so that Intermediate products that can be used in the formation process, such as acidic solution, vanadium-rich slag, ammonium chloride, etc., are recycled in the vanadium extraction process.

Therefore, this method has the following characteristics: 1) the process is simple, the process is reasonable, the production cost is reduced, and the economic benefit is improved; 2) the "three wastes" are converted into the intermediate products required in the process, and the waste is truly turned into wealth; 3) the environment Friendly, energy saving and emission reduction effect is remarkable.

Claims (1)

1. An online circulation method for the process of extracting vanadium from stone coal, which adopts "decarburization-sodium roasting-water leaching-acid leaching-ion resin exchange-acidic ammonium salt precipitation vanadium-deammoniation calcination" to extract the raw stone coal ore. Vanadium process characterized by: (1) carry out one-stage spraying to the acid flue gas that sodiumization roasting operation produces with the adsorption lower liquid that produces in the ion resin exchange operation, return the acid leaching operation through the acidic solution that one-stage spraying forms; (2) neutralize the acid leaching solution obtained in the acid leaching process to obtain vanadium-rich slag and treatment solution; the vanadium-rich slag returns to the sodium roasting process, and the treatment solution reaches the standard and is discharged; (3) The vanadium precipitation mother liquor produced in the acidic ammonium salt vanadium precipitation process is stripped to produce ammonia and alkaline treatment liquid, and the ammonia gas produced in the stripping process and the ammonia gas produced in the deamination and calcination process are sprayed with hydrochloric acid solution to produce chlorine Ammonium chloride and ammonium chloride return to the acidic ammonium salt vanadium precipitation process; the alkaline treatment liquid performs secondary spraying on the acidic flue gas that has been sprayed in the primary level, and the flue gas is discharged after the secondary spraying, and the formed spray liquid Return to the water immersion process; The vanadium pentoxide grade of the raw stone coal ore is ≥0.7%; The neutralization treatment is: first preheating the low-concentration vanadium-containing acid leaching solution obtained by acid leaching with a vanadium pentoxide concentration of 100-300mg/l to 20-45°C, and then setting the ratio of n _V :n _Fe =1:1~1:3 Add FeSO ₄ ·7H ₂ O to the pickling solution, then adjust to pH=4~6, react at 45~60°C for 10~30min, and finally pass solid-liquid The vanadium-rich slag and treatment liquid are separated.

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