Method for extracting tungsten and molybdenum through acid decomposition of high-molybdenum scheelite

Abstract

The invention relates to a method for extracting tungsten and molybdenum through acid decomposition of high-molybdenum scheelite. The method comprises the following steps: leaching the high-molybdenumscheelite with an acid solution, and extracting a leachate to extract molybdenum; extracting a leaching residue with hydrogen peroxide to obtain a solution containing peroxotungstic acid and peroxymolybdic acid, and heating or introducing SO2 to obtain tungstic acid and a solution containing the peroxomolybdic acid; extracting the tungstic acid with hydrogen peroxide, and heating or introducing SO2 to obtain tungstic acid and a solution containing the peroxomolybdic acid; repeating for several times till pure tungstic acid is obtained; preparing tungsten trioxide or tungsten powder from the pure tungstic acid; and heating or introducing SO2 into the solution containing the peroxomolybdic acid, dissolving obtained molybdic acid in a hydrogen peroxide solution to prepare a peroxomolybdic acid solution, and performing ultrasonic spraying pyrolysis to prepare molybdenum trioxide powder or molybdenum powder. By the method, the separation effect is good and the operation process is simple and easy to control, so that the method is easy to popularize and apply industrially.

Description

technical field [0001] The invention relates to the technical field of rare metal metallurgy, in particular to a method for acid-decomposing high-molybdenum scheelite to extract tungsten and molybdenum. Background technique [0002] At present, the mainstream technology for processing high-molybdenum scheelite in the industry is to first use alkaline reagents such as sodium hydroxide or sodium carbonate to obtain crude sodium tungstate solution and alkali boiling residue by pressure cooking. The crude sodium tungstate solution contains a certain amount of molybdenum, which needs to be vulcanized first, and then acidified to precipitate and separate molybdenum in the form of molybdenum trisulfide. This process will inevitably produce a large amount of toxic gas hydrogen sulfide. The acidified solution adopts a weakly basic extractant or a weakly basic ion exchange resin to absorb tungsten in it, and then back-extracts or desorbs with ammonia water to obtain an ammonium tungs...

AI Technical Summary

Problems solved by technology

This mainstream technology is currently facing several serious problems: First, alkaline pressure cooking needs to consume alkali such as sodium hydroxide or sodium carbonate. The cost of scheelite decomposition is very high; secondly, alkali pressure cooking will produce alkali cooking slag, which has been listed in the national hazardous waste catalogue, and tungsten smelting enterprises are not allowed to dispose of it at will, and must be handed over to qualified enterprises for paid treatment, and The state also charges 2,000 yuan / ton of environmental protection tax on the hazardous waste alkali cooking slag, which greatly increases the cost of tungsten smelting; third, in order to separate the associated molybdenum in scheelite, it is necessary to add sulfide to separate molybdenum by sulfide , the process will produce toxic gas hydrogen sulfide that will endanger production and the environment; fourth, in order to produce tungsten products with qualified impurity content, ammonia water or ammonium chloride and other ammonia reagents must be used as transformation reagents in the current tungsten smelting process , so the production process will inevitably produce a large amount of ammonia nitrogen wastewater, resulting in environmental pollution

Moreover, the main purpose of its invention is to separate tungsten and molybdenum according to the stability difference between peroxytungstic acid and peroxymolybdic acid in acidic solution, and does not involve the purification method of tungsten

Images