Method for extracting tungsten from scheelite

A technology of scheelite and phosphoric acid, applied in the direction of improving process efficiency, etc., can solve the problems of affecting decomposition rate, non-volatile, low corrosion, etc., and achieve the effect of simple leaching equipment, increasing liquid-solid ratio, and simplifying operation

Active Publication Date: 2011-04-20
CENT SOUTH UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0014] The object of the present invention is to provide a method for decomposing scheelite, which has low corrosion and no volatility, realizes efficient decomposition of scheelite, and solves the problem of During the decomposition process, the tungsten ore is wrapped to affect the decomposition rate, and the decomposition slag is difficult to filter and wash, resulting in the loss of tungsten, etc.

Method used

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  • Method for extracting tungsten from scheelite
  • Method for extracting tungsten from scheelite
  • Method for extracting tungsten from scheelite

Examples

Experimental program
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Effect test

Embodiment 1

[0033] On the basis of using phosphoric acid and sulfuric acid mixed acid to decompose scheelite, by adding CaSO 4 2H 2 O seeds to reduce the supersaturation of the solution, and maintain a constant, relatively low reaction temperature to make the crystals grow uniformly, and at the same time increase the liquid-solid ratio of the leaching system to reduce the large concentration fluctuations caused by the consumption of sulfate ions, etc. Measures to obtain a single crystalline product, the experimental results are as follows.

[0034] Scheelite (including WO 3 70.6%) 1kg to prepare a mixed solution of phosphoric acid and sulfuric acid, P 2 o 5 Content is 20%, control SO 4 2- The concentration is 0.15g / ml, the amount of dihydrate gypsum seed crystals added is 50g, the liquid-solid ratio is 10:1, the reaction temperature is 60°C, and the reaction time is 6h. The leaching rate of tungsten is 99.4%. A Buchner funnel with a specification of 200mm is used to filter the slur...

Embodiment 2

[0039] Scheelite (including WO 3 70.6%) 1kg to prepare a mixed solution of phosphoric acid and sulfuric acid, P 2 o 5 Content is 25%, control SO 4 2- The concentration is 0.10g / ml, the amount of dihydrate gypsum seed crystal is 100g, the liquid-solid ratio is 12:1, the reaction temperature is 80°C, and the reaction time is 4h. The leaching rate of tungsten is 99.6%. A Buchner funnel with a specification of 200mm was used to filter the slurry, and the time required for filtration was 30 minutes. Then, the filter cake was washed with pure water three times, and the water consumption was 300ml each time. After washing, the filter cake contained P 2 o 5 down to 1.2%. The filtrate is adsorbed by secondary amine-based anion exchange resin, and the adsorption rate of tungsten is 99.1%. In the ion exchange process, phosphorus is lost in the form of phosphotungstic heteropolyacid and the total loss of entrainment is 3.7%. The mother liquor is added to the lost phosphoric acid an...

Embodiment 3

[0041] Scheelite (including WO 3 70.6%) 1kg to prepare a mixed solution of phosphoric acid and sulfuric acid, P 2 o 5 Content is 15%, control SO 4 2- The concentration is 0.20g / ml, the amount of dihydrate gypsum seed crystal is 1g, the liquid-solid ratio is 6:1, the reaction temperature is 50°C, and the reaction time is 8h. The leaching rate of tungsten is 99.0%. A Buchner funnel with a specification of 200mm is used to filter the slurry, and the time required for filtration is 1h, and then the filter cake is washed with pure water three times, and the water consumption is 300ml each time. After washing, the filter cake contains P 2 o 5 down to 3.4%. The filtrate is adsorbed by quaternary ammonium-based anion exchange resin, and the adsorption rate of tungsten is 98.9%. In the ion exchange process, phosphorus is lost in the form of phosphotungstic heteropoly acid and the total loss of entrainment is 3.1%. The mother liquor is added to the lost phosphoric acid and sulfur...

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Abstract

The invention discloses a method for extracting tungsten from scheelite, comprising the following steps of: mixing the scheelite with a mixed solution of phosphoric acid and sulfuric acid for reaction, adding dihydrate gypsum as seed crystals, and controlling the concentration of SO4<2->, the content of P2O5 and the reaction temperature to obtain the dihydrate gypsum with good filtering and washing properties. The invention has the advantages that one-step efficient normal pressure leaching of the scheelite is achieved, thus resources and energy consumption are saved, and the resolution ratio of the scheelite is up to above 98%; the problems of Cl<-> corrosion and serious HCl volatilization are overcome; the cyclic utilization of phosphoric acid is basically achieved, and the leaching cost and waste water discharge are greatly reduced; leaching equipment is simple, is convenient for operation and is easy to realize industrialization; the single and stable dihydrate gypsum is obtained, the filter efficiency of the dihydrate gypsum is high, the washing property of the dihydrate gypsum is good, and the P2O5 content in the washed dihydrate gypsum is reduced to be below 2%, thereby reducing the loss of phosphoric acid; and the passivation phenomenon of calcium sulfate solid film when the tungsten ore is leached is avoided.

Description

technical field [0001] The invention relates to the extraction of rare high-melting-point metal tungsten in the field of hydrometallurgy, in particular to an efficient method for extracting tungsten from scheelite. Background technique [0002] At present, the main resource consumed by tungsten smelting in my country is black tungsten ore (easy to smelt, and the output accounts for more than 90%), while the basic reserves of black tungsten resources are only about 491,300 tons, which will be exhausted within a few years. In addition, the newly discovered tungsten Most of the resources are complex scheelite resources, and scheelite has shown an absolute advantage (the reserves of scheelite resources are about 1.737 million tons, accounting for 72.1% of the basic reserves of tungsten ore in my country). Therefore, developing scheelite resources to replace black tungsten is a strategic choice for the sustainable development of my country's tungsten industry. [0003] However, t...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22B3/06C22B34/36
CPCY02P10/20
Inventor 赵中伟李江涛李洪桂
Owner CENT SOUTH UNIV
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