CN102094123A - Method for extracting vanadium from vanadium-containing steel slag by using highly-alkaline sodium hydroxide medium - Google Patents

Abstract

The invention relates to a method for extracting vanadium from vanadium-containing steel slag by using a highly-alkaline sodium hydroxide medium, belonging to the technical field of metallurgy. The technical scheme comprises the following steps: adding steel slag, water and NaOH into a reactor together, wherein the mass concentration of the NaOH solution is 65-90%; decomposing and leaching under atmospheric pressure, and diluting the obtained slurry with a diluter to obtain a slurry mixture; and separating the slurry mixture by filtering at constant temperature, and washing the slag with a washing solution to obtain tailings and a vanadium-containing water solution. The method provided by the invention can be implemented under atmospheric pressure at low temperature (greatly lower than the roasting temperature in the traditional pyrogenic process), and is easy to operate and safe; and the extraction rate of vanadium is greatly higher than that of the existing vanadium recovery technique based on the pyrogenic process and wet process, the one-time recovery rate of vanadium is 85-90%, and the total content of vanadium in the tailings is 0.3-0.6 wt%. The invention solves the problem that vanadium in the vanadium-containing steel slag can not be easily recovered, and has the advantages of high recovery rate of vanadium, low production cost, favorable economic benefit and environmental benefit, and the like.

Description

A method for extracting vanadium from vanadium-containing steel slag with high alkalinity sodium hydroxide medium

technical field

The invention relates to a method for extracting vanadium from vanadium-containing steel slag by using a high-alkalinity sodium hydroxide medium, belonging to the technical field of metallurgy.

Background technique

Vanadium-containing steel slag is vanadium-containing steel slag formed by direct steelmaking (normal slagging) of vanadium-containing molten iron due to various reasons (without oxidation and vanadium extraction process) and containing V2O5 at 2% to 10%. Compared with normal vanadium slag, its calcium The content is greatly exceeded. Due to its high calcium and iron content, low vanadium content, complex occurrence state of vanadium, and dispersed distribution in various mineral phases, it is difficult to recycle vanadium in it by traditional fire roasting extraction process. In my country, millions of tons of vanadium-containing steel slag are discharged without treatment every year, which not only causes the loss of vanadium resources, but also causes environmental burdens. Although there are many vanadium extraction processes, it is difficult to adapt to the resource characteristics of vanadium-containing steel slag, and there are many problems such as high cost, heavy pollution, and low recovery rate. The traditional wet vanadium extraction process mainly uses sodium or calcification roasting plus leaching method to extract vanadium. The vanadium leaching rate of the sodium roasting process is low, the consumption of sodium salt is large, the roasting temperature is high, and the energy consumption is high. Moreover, this process is not suitable for the extraction of vanadium from high-basic steel slag with low vanadium content and high CaO. Calcification roasting has a certain selectivity for materials, but it has problems such as low conversion rate and high cost for general steel slag, which is not suitable for mass production. In addition, pyrometallurgy is used to recover vanadium in steel slag. This process is to add vanadium-containing steel slag to sintered ore as a flux and enter the blast furnace for smelting. Vanadium is enriched in molten iron to increase the vanadium content of molten iron, and then blowing High-grade vanadium slag is obtained to prepare V2O5 or vanadium-iron alloy. This method is prone to cyclic enrichment of phosphorus and sulfur in molten iron, which aggravates the task of dephosphorization and sulfur removal in steelmaking. In addition, steel slag has many impurities and relatively low effective calcium oxide content, which will reduce the grade of sinter ore and increase energy consumption in the ironmaking process, so it is not suitable to mix in large quantities. Therefore, the processing capacity of vanadium-containing steel slag in this process cannot meet the actual production needs. And some emerging technologies such as selective precipitation, microbial leaching, ore slurry electrolysis, etc., are used in the research of vanadium extraction from vanadium-containing steel slag. limitation.

Contents of the invention

The purpose of the present invention is to provide a method for extracting vanadium from vanadium-containing steel slag with a high-basic sodium hydroxide medium, which has a high recovery rate (85% to 90%) and low leaching temperature (180 %) to vanadium-containing steel slag ~240°C), so that the steel slag treatment process can be carried out under wet conditions, without the need for high-temperature roasting, shortening the reaction time, realizing a single high-efficiency extraction of vanadium, and solving the above-mentioned problems in the background technology.

Technical method of the present invention is as follows:

A method for extracting vanadium from vanadium-containing steel slag using a high-alkalinity sodium hydroxide medium, including the following process: the steel slag raw material is crushed into particles of ≤20mm and then ground into -100 mesh powder, and mixed with water and sodium hydroxide medium Add the reactor together, wherein, the mass ratio of sodium hydroxide and steel slag is 3:1 to 5:1, the mass concentration (effective action concentration) of sodium hydroxide medium is 65～90%; Carry out decomposition stripping under normal pressure condition, The reaction temperature is 180~240℃, and the effective reaction time is 1~6h; then the obtained reaction slurry is diluted with a diluent to obtain a mixed slurry containing sodium hydroxide, sodium vanadate, sodium silicate and tailings; control leaching The alkalinity of the pulp is 100~400g/L. The mixed slurry is separated by heat preservation and filtration at 80~130℃, and the slag is washed with detergent to obtain tailings and vanadium-containing aqueous solution, and then the impurities and vanadium are removed by conventional methods. Recycle.

The sodium hydroxide medium is based on sodium hydroxide, including pure sodium hydroxide and sodium hydroxide mixed with sodium salts in different proportions. The sodium salts include sodium nitrate, sodium carbonate, and sodium chloride.

For different vanadium-containing steel slags, the reaction conditions are different. The steel slag containing vanadium in a high-valent oxidation state can be reacted without any gas, that is, vanadium can be recovered in an open atmospheric pressure reactor; Vanadium steel slag in the state needs to be fed with oxidizing gas, such as air or oxygen.

The diluent used is water or a dilute alkaline solution.

The detergent used is a solution containing 100~400g/L of alkali.

Beneficial effects of the present invention: the reaction temperature of the present invention is low (180-240°C), and the dissolution rate is high (85%-90%), so that the steel slag treatment process can be carried out under wet conditions, without high-temperature roasting, and under low temperature and normal pressure It can be carried out, the reaction time is shortened, the operation is easy, the process is simple and the safety is good, and a single high-efficiency extraction of vanadium is realized; and in the process of vanadium extraction, air pollution such as Cl2, HCl, dust, SO2, etc. caused by roasting is effectively eliminated things. In addition, during the leaching process, the liquid phase produced is returned to the leaching process for recycling, which effectively reduces the amount of waste water produced and discharged, and fundamentally solves the problem of high reaction temperature (high energy consumption) of the traditional roasting vanadium extraction process and the impact on vanadium-containing steel slag. Medium vanadium, difficulty in recovery and resource utilization, low recovery rate of vanadium, large discharge of three wastes, etc., has the advantages of low production cost, good economic and environmental benefits, etc.

Description of drawings

Fig. 1 is the process flow diagram of the embodiment of the present invention.

Detailed ways

The technical solution of the present invention will be further described through the embodiments below in conjunction with the accompanying drawings.

In each embodiment of the present invention, vanadium-containing steel slag is converter steel slag, and its chemical composition is as follows:

TiO2 =4.82%; MnO= 1.70%; TFe =15.27%; S =0.281%; V2O5 =3.63%; Cr2O3= 1.18%; FeO =7.76%; Al2O3= 2.79%; SiO2= 11.23%; MgO = 11.80%; P = 0.594%.

NaOH is analytical pure or industrial pure. Industrial pure NaOH contains 96.0% sodium hydroxide, 1.3% sodium carbonate, and 2.7% sodium chloride.

Example 1:

A method for extracting vanadium from vanadium-containing steel slag using high-alkalinity sodium hydroxide medium: Weigh 200g of solid industrial NaOH into a reaction kettle, add 50mL of deionized water to an initial concentration of 60%, start stirring, and the stirring speed is 600rpm , heated up to 200°C, weighed 50g of vanadium-containing steel slag and put it in the reactor, and the reaction time was 6h; at the end of the reaction, 400mL of water was added to the reactor to dilute, filtered by suction, the alkalinity of the liquid phase was 345g/L, and the slag was Washing three times; using chemical and instrumental analysis to analyze the content of vanadium in the slag phase and liquid phase, the total vanadium content in the tailings is 0.435wt% (calculated as vanadium pentoxide), and the leaching rate of the obtained vanadium is 87.5%.

Example 2:

A method for extracting vanadium from vanadium-containing steel slag with high-alkalinity sodium hydroxide medium: Weigh 200g of solid analytical pure NaOH in a reaction kettle, add 50mL of deionized water to an initial concentration of 80%, turn on stirring, and stir at a speed of 600rpm, heat up to 240°C, weigh 50g of vanadium-containing steel slag and put it in the reaction kettle, and the reaction time is 4h. At the end of the reaction, add 400mL of water to the reaction kettle to dilute, filter with suction, the alkalinity of the liquid phase is 356.5g/L, wash the slag three times; use chemistry and instruments to analyze the content of vanadium in the slag phase and liquid phase. The total amount of vanadium is 0.338wt% (calculated as vanadium pentoxide), and the leaching rate of the obtained vanadium is 90.3%.

Example 3

A method for extracting vanadium from vanadium-containing steel slag with a high-alkalinity sodium hydroxide medium: Weigh 175g of solid analytical pure NaOH and 25g of NaNO3 in a reaction kettle, add 50mL of deionized water to an initial alkali concentration of 70%, nitric acid The initial concentration of sodium is 10%; turn on the stirring, the stirring speed is 600rpm, heat up to 220°C, weigh 50g of vanadium-containing steel slag and put it in the reaction kettle, and the reaction time is 5h; The basicity of the phase is 346.40g/L, and the slag is washed three times; the content of vanadium in the slag phase and liquid phase is analyzed by chemical and instrumental analysis. The total amount of vanadium in the tailings is 0.452wt% (calculated as vanadium pentoxide), and the leaching rate of vanadium obtained is 87%.

Example 4

A method for extracting vanadium from vanadium-containing steel slag with high-alkalinity sodium hydroxide medium: Weigh 200g of solid analytical pure NaOH in a reaction kettle, add 50mL of deionized water to an initial concentration of 80%, turn on stirring, and stir at a speed of 600rpm, heat up to 180°C, weigh 50g of vanadium-containing steel slag and put it in the reactor, and the reaction time is 5h; at the end of the reaction, add 400mL of water to the reactor to dilute, filter with suction, the alkalinity of the liquid phase is 335.40g/L, and the Wash the slag three times; use chemical and instrumental analysis to analyze the content of vanadium in the slag phase and liquid phase. The total amount of vanadium in the tailings is 0.622wt% (calculated as vanadium pentoxide), and the leaching rate of vanadium obtained is 82.1%.

Example 5

A method for extracting vanadium from vanadium-containing steel slag with a high-alkalinity sodium hydroxide medium: Weigh 200g of solid analytical pure NaOH into the reaction kettle, add 50mL of deionized water to an initial concentration of 90%, turn on the stirring, and the stirring speed 600rpm, heat up to 180°C, weigh 50g of vanadium-containing steel slag and put it in the reactor, and the reaction time is 5h; at the end of the reaction, add 400mL of water to the reactor to dilute, filter with suction, the alkalinity of the liquid phase is 335.40g/L, and the Wash the slag three times; use chemical and instrumental analysis to analyze the content of vanadium in the slag phase and liquid phase. The resulting vanadium leaching rate was 82.1%.

Claims (8)

1. A method for extracting vanadium from vanadium-containing steel slag with a high-basic sodium hydroxide medium, which is characterized in that it comprises the following process: the steel slag raw material is broken into particles of ≤ 20mm and then ground into -100 mesh powder, and mixed with water and sodium hydroxide medium are added to the reactor together, wherein the mass ratio of sodium hydroxide to steel slag is 3:1 to 5:1, and the mass concentration of sodium hydroxide medium is 65 to 90%; it is decomposed and stripped under normal pressure conditions, The reaction temperature is 180~240℃, and the effective reaction time is 1~6h; then the obtained reaction slurry is diluted with a diluent to obtain a mixed slurry containing sodium hydroxide, sodium vanadate, sodium silicate and tailings; control leaching The alkalinity of the pulp is 100~400g/L. The mixed slurry is separated by heat preservation and filtration at 80~130℃, and the slag is washed with detergent to obtain tailings and vanadium-containing aqueous solution, and then the impurities and vanadium are removed by conventional methods. Recycle. 2. according to claim 1 with the method for extracting vanadium from vanadium-containing steel slag with the described sodium hydroxide medium of high alkalinity, it is characterized in that said sodium hydroxide medium is to be matrix with sodium hydroxide, comprising pure hydrogen Mixed medium of sodium oxide and sodium hydroxide with different proportions of sodium salts. 3. the method for extracting vanadium from vanadium-containing steel slag with the sodium hydroxide medium of high basicity according to claim 1 or 2, is characterized in that: the steel slag containing the vanadium of high-valent oxidation state reacts without feeding any It is carried out under gas conditions, that is, vanadium can be recovered in an open atmospheric pressure reactor. 4. the method for extracting vanadium from vanadium-containing steel slag with the sodium hydroxide medium of high alkalinity according to claim 1 or 2, is characterized in that: the steel slag containing the vanadium of low-valent oxidation state needs to pass into oxidizing gas . 5. the method for extracting vanadium from vanadium-containing steel slag with the sodium hydroxide medium of high alkalinity according to claim 2, it is characterized in that said sodium salt comprises sodium nitrate, sodium carbonate, sodium chloride. 6. the method for extracting vanadium from vanadium-containing steel slag with the sodium hydroxide medium of high alkalinity according to claim 4, it is characterized in that the steel slag containing the vanadium of low price oxidation state needs to pass into air or oxygen. 7. The method for extracting vanadium from vanadium-containing steel slag with high alkalinity sodium hydroxide medium according to claim 1 or 2, characterized in that the diluent used is water or dilute alkali solution. 8. The method for extracting vanadium from vanadium-containing steel slag with a high-basic sodium hydroxide medium according to claim 1 or 2, wherein the detergent used is a solution containing 100-400 g/L of alkali.

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