Method for extracting tungsten and molybdenum by decomposing high-molybdenum scheelite by electro-oxidation method

A technology of scheelite and electro-oxidation, applied in the direction of improving process efficiency, etc., can solve problems such as harsh working environment, waste of chemical raw materials, hindered reaction, etc., and achieve the effects of overcoming impact, reducing burden, and saving energy

Active Publication Date: 2019-05-17
UNIV OF SCI & TECH BEIJING
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Problems solved by technology

Due to the requirements of the subsequent tungsten and molybdenum separation process, the pH needs to be adjusted, and a large amount of soluble sodium salt solution is finally produced, which causes waste of chemical raw materials and environmental problems after discharge.
In contrast, the hydrochloric acid decomposition method can realize the separation of tungsten and molybdenum during the leaching process, so that tungsten remains in the leaching slag as tungstic acid, and molybdenum enters the solution, but the colloidal tungstic acid generated during the reaction will be wrapped on the surface of scheelite , hinder the reaction, resulting in a lower leaching rate
Impurities such as phosphorus, arsenic, and silicon in minerals can form soluble heterotungstic polyacids with tungsten under acidic conditions, resulting in the loss of tungsten in the solution
In addition, hydrochloric acid volatilization and corrosion problems are serious during operation, and the working environment is harsh, so it is basically not used at present.

Method used

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  • Method for extracting tungsten and molybdenum by decomposing high-molybdenum scheelite by electro-oxidation method
  • Method for extracting tungsten and molybdenum by decomposing high-molybdenum scheelite by electro-oxidation method
  • Method for extracting tungsten and molybdenum by decomposing high-molybdenum scheelite by electro-oxidation method

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] Scheelite (containing WO 3 51%, Mo 3.2%) was added to the sulfuric acid solution for electrooxidation leaching, and the H 2 SO 4 The concentration is 20%, the electrolysis temperature is 50°C, the reaction time is 3h, the liquid-solid ratio of the slurry is 8:1, the leaching rates of tungsten and molybdenum are divided into 98.3% and 98.4%, and after filtering and washing, the filter cake is washed with pure water three times to obtain the leaching residue. Characterize it, XRD figure and SEM picture are as follows figure 2 , as shown in 3. The filtrate uses 35% TBP+65% sulfonated kerosene, and extracts molybdenum according to O / A=1. The extraction rate of molybdenum is 93.8%, and the extraction rate of tungsten is 1.05%. The loaded organic phase is back-extracted with ammonia water to obtain a crude ammonium molybdate solution. The raffinate was thermally decomposed at 90°C, and the precipitation rate of tungsten was 99.1%. The XRD and SEM spectra of the product a...

Embodiment 2

[0026] Scheelite (containing WO 3 45%, Mo 2.5%) into the sulfuric acid solution for electro-oxidation leaching, control H 2 SO 4 The concentration is 25%, the electrolysis temperature is 55°C, the reaction time is 3h, the slurry liquid-solid ratio is 7:1, the leaching rates of tungsten and molybdenum are 98.8% and 98.6%, and the filter cake is washed three times with pure water after filtration and washing to obtain leaching residue. The filtrate uses 35% N235+65% sulfonated kerosene to extract molybdenum according to O / A=2, the extraction rate of molybdenum is 94.9%, and the extraction rate of tungsten is 1.5%. The raffinate is thermally decomposed at 95°C, and the precipitation rate of tungsten is 99.2%. The mother liquor is added with sulfuric acid and hydrogen peroxide to the initial concentration and then returns to leaching. The powdery tungstic acid obtained by thermal decomposition is subjected to ammonia dissolution-impurity removal-evaporation crystallization to o...

Embodiment 3

[0028] Scheelite (containing WO 3 45%, Mo 2.5%) into the sulfuric acid solution for electro-oxidation leaching, control H 2 SO 4 The concentration is 25%, the electrolysis temperature is 55°C, the reaction time is 3h, the liquid-solid ratio of ore slurry is 7:1, the leaching rates of tungsten and molybdenum are divided into 99.2% and 99.1%, and the filter cake is washed three times with pure water after filtration and washing to obtain leaching residue. The filtrate uses 35% TBP+65% sulfonated kerosene, O / A=1:2 to extract molybdenum, the extraction rate of molybdenum is 94.8%, and the extraction rate of tungsten is 1.2%. The loaded organic phase is back-extracted with ammonia water to obtain crude ammonium molybdate solution . The raffinate was passed through SO at 40°C 2 Gas, the precipitation rate of tungsten is 99.0%, and the mother liquor is added with sulfuric acid and hydrogen peroxide to the initial concentration and then returns to leaching. The powdery tungstic a...

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Abstract

The invention relates to a method for extracting tungsten and molybdenum by decomposing high-molybdenum scheelite by an electro-oxidation method. The method comprises the steps that electro-oxidationleaching of the high-molybdenum scheelite is carried out in a sulfuric acid system, coordination of tungsten and molybdenum with active oxygen generated by an anode to form soluble peroxy tungstic acid and peroxy molybdic acid, solid-liquid separation is carried out after complete decomposition, and ammonium paramolybdate is obtained after filtrate is subjected to processes of extraction of molybdenum-back extraction-removing impurities, raffinate is subjected to high temperature decomposition or SO2 reduction to obtain powdery tungstic acid, after hydrogen peroxide and sulfuric acid are addedinto mother liquor for supplement to initial concentration, returning leaching is carried out, and ammonium paratungstate is obtained after tungstic acid is subjected to processes of ammonia neutralization-removing impurities and the like. The method realizes high-efficiency normal-pressure leaching of the high-molybdenum scheelite, any impurities does not be introduced in the leaching process, energy is saved, subsequent purification burden is reduced, and the leaching rates of tungsten and molybdenum in the leaching process can reach more than 98%; the separation process of tungsten and molybdenum can realize extraction and molybdenum extraction without additional reagents, and the separation efficiency is high; the produced tungstic acid has less impurity content, a leaching agent canbe recycled, and the leaching cost and wastewater discharge are reduced; and the process is easy to operate.

Description

technical field [0001] The invention belongs to the field of non-ferrous metallurgy, and relates to a new method for extracting tungsten and molybdenum by decomposing high-molybdenum scheelite by electro-oxidation. technical background [0002] my country is the world's largest tungsten-producing country, ranking first in the world in terms of tungsten reserves, product output, export volume and consumption, and holds the dominance of the world's tungsten market. Although my country is rich in tungsten resources, it has long relied on high-quality black tungsten resources that are easy to smelt and smelt, resulting in a small amount of reserves. At present, scheelite has an absolute advantage. However, my country's scheelite has low grade, few rich ore, and complex composition of ore deposits. There are more than 30 kinds of associated components, mainly including tin, molybdenum, bismuth, lead, zinc, rare earth, fluorite and so on. Among them, molybdenum and tungsten exist...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22B34/36C22B34/34C22B3/08
CPCY02P10/20
Inventor 张文娟王成彦马保中
Owner UNIV OF SCI & TECH BEIJING
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