A kind of technique for preparing ammonium tungstate solution

Abstract

The invention discloses a technology for preparing an ammonium tungstate solution. The technology is characterized in that a (AO)x(WO3)y(BO)z-containing material is used as a raw material, A and B represents divalent metals, (x+z) / y=3, raw material granularity is less than or equal to 200 micrometers, a seed crystal use amount is in a range of 0-15g / L, a leaching agent solution selection principle at least comprises that raw material reactants contain substances capable of re-synthesizing the leaching agent and the leaching agent contains NH4<+> and has a concentration greater than 10g-NH4<+> / 100g-H2O, a use amount of the leaching agent is at least 1.0 times a required amount (theoretical amount) of the leaching agent for transforming clinker AO and BO into corresponding difficultly soluble salts, a leaching system pH value is controlled to greater than or equal to 8, a leaching process is carried out under enclosed conditions, leaching system absolute pressure is greater than or equal to 1atm, a leaching temperature is in a range of 15-100 DEG C, leaching time is in a range of 0.1-10.0h, an initial liquid-solid ratio of the leaching system is greater than or equal to 3: 1mL / g, through a multistage feeding method, the final liquid-solid ratio of the leaching system is reduced, and after leaching, leaching slurry is subjected to separation and washing to form an ammonium tungstate solution. The technology realizes low-cost, no waste water discharge and high-efficiency preparation of the high-concentration ammonium tungstate solution.

Description

technical field [0001] The invention relates to a process for preparing ammonium tungstate solution, belonging to the technical field of tungsten metallurgy. Background technique [0002] Ammonium tungstate solution is an important intermediate material in the process of preparing APT in the tungsten smelting industry. [0003] At present, the preparation methods of ammonium tungstate solution used in industry mainly include: [0004] 1) pressure cooking soda , mainly using tungsten ore as raw material, through caustic soda decomposition or soda pressure cooking, etc., firstly prepare sodium tungstate solution, and then transform into ammonium tungstate solution through ion exchange or solvent extraction. The problems of this method include: caustic soda Or the amount of soda is large, and the consumption of auxiliary materials is large; the leaching temperature is high, and the operating conditions are relatively harsh; the transformation process produces a large amount o...

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Problems solved by technology

[0004] 1) pressure cooking soda , mainly using tungsten ore as raw material, through caustic soda decomposition or soda pressure cooking, etc., firstly prepare sodium tungstate solution, and then transform into ammonium tungstate solution through ion exchange or solvent extraction. The problems of this method include: caustic soda Or the amount of soda is large, and the consumption of auxiliary materials is large; the leaching temperature is high, and the operating conditions are relatively harsh; the transformation process produces a large amount of saline wastewater, which causes serious environmental pollution; the process is complicated and the cost is high;

Although this method can greatly reduce the amount of soda used and reduce the discharge of acid-base waste liquid, it has been gradually replaced by the wet method because of the large amount of slag returned, high energy consumption and high cost;

[0006] 3) acid decomposition , Decompose tungsten minerals with acid to obtain crude tungstic acid, and then convert it into ammonium tungstate solution. Although this method can greatly reduce wastewater discharge, there are problems such as equipment corrosion, acid pollution, and poor adaptability to raw materials;

[0007] 4) ammonium salt decomposition method , mainly including ammonium fluoride decomposition and ammonium phosphate decomposition. This method can directly obtain ammonium tungstate solution when treating scheelite, and the leaching rate of impurities is low. It can realize closed-circuit scheelite smelting and zero discharge of waste water. However, the price Relatively expensive fluorine and phosphorus compounds, and their consumption is relatively large, resulting in poor economy;

[0008] 5) Tungsten ore roasting-ammonia leaching method (CN102642871A), tungsten concentrate and silicon dioxide are mixed and roasted to obtain a fired product containing tungsten trioxide, and ammonium tungstate solution is obtained after leaching with ammonia water, which can solve the discharge problem of waste water, but ammonia water has poor stability and is easy to decompose , resulting in a higher pressure in the leaching system

However, although the existing technology has experienced long-term arduous exploration, it has not been able to be realized

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