Process for preparing high purity ammonium para-tungstate using hihg-molybdenum tungsten ore

Abstract

The present invention provides a method of treating high-molybdenum tungsten mineral or tungsten slime by means of three-ion column exchange molybdenum-eliminating technology so as to obtain ammoniumpara-tungstate with high purity at low cost. The treating process includes grinding, alkali leaching, filtering and concentration to obtain sodium tungstate crystal; water dissolving, filtering and sulfurizing sodium tungstate; ion exchange to eliminate molybdenum; desulfurizing sodium tungstate liquid; ion exchange to elimiante impurity and desorbing tungsten with ammonia water and ammonium chloride solution to prepare ammonium tungstate solution; and evaporation to obtain ammonium para-tungstate crystal. The present invention has low cost.

Description

technical field [0001] The invention relates to a method for preparing high-purity ammonium paratungstate from high-molybdenum-tungsten ore, which belongs to the technical field of metallurgy and chemical industry. Background technique [0002] my country's tungsten ore reserves, mining volume, primary product production volume and export volume rank first in the world. Due to a large number of mining and disorderly competition, the supply of black tungsten concentrate in my country has decreased accordingly. A large number of ore sources are black and white tungsten mixed ore and tungsten fine mud, etc., all of which contain relatively high impurities such as molybdenum and calcium. Since tungsten and molybdenum belong to the VIB group in the periodic table of elements, their ionic radii are close, so their chemical properties are similar. Therefore, the separation of tungsten and molybdenum has become a worldwide problem in the extraction and metallurgy of tungsten. There ...

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Problems solved by technology

The prepared ammonium tungstate solution was added (NH 4 ) 2 The price of S vulcanizing agent is high, and ion exchange is used to remove molybdenum. First, desorbent is used to desorb tungsten, and then molybdenum desorbing agent is used to decompose molybdenum. Therefore, the cost of desorbent is relatively high. If the free sulfur of ammonium tungstate after molybdenum removal is too high , a part of it may enter the ammonium paratungstate product during the evaporation process, resulting in too high sulfur content. In addition, the desorption process of molybdenum is unstable, and sometimes the temperature is too high to burn out the resin if it is not well controlled.

Therefore, the processing cost of applying this patent is relatively high, which affects its popularization and application.

(2) Although the process of the patent is shortened, the cost of the vulcanizing agent (NaHS) is high and the cost of the pH adjustment method is high. Although the ion exchange adopts multi-column adsorption, the adsorption capacity is high, but due to the one-step ion exchange process, it is necessary to Vulcanized material diluted to WO 3 15-20g / l, the amount of feed liquid is too large, the size of multiple columns is different, and the flow rate varies greatly. If the molybdenum removal is guaranteed, the production volume will be affected. If the production volume is guaranteed, the flow rate of the molybdenum removal column (smaller column) will be lower is too big

In addition, there is a big problem in the production of ammonium paratungstate in this patent that has not been solved, that is, there must be excessive S in the general vulcanization process. 2- , to guarantee MoS 4 2- Thio is more complete, and S 2- Greater affinity for anion resin than WO 4 2- , even if the feed liquid contains a small amount of S 2- , will also be adsorbed on the exchange column resin, and when desorbed by high Cl - After desorption, sulfide pollutes the resin, part of which will enter the ammonium tungstate solution, resulting in unqualified products, and another part of sulfide will enter the old agent. There are many problems in the application, and the promotion cannot be successful

Although the patent of (3) can improve the adsorption capacity, the molybdenum removal rate is higher, the desorption speed is faster, and the reagent consumption is less, but the production efficiency will not be very high. Strictly speaking, the ion exchange process is not completely continuous, because it is necessary to regularly absorb the full The resin is moved out of the column, and the regenerated resin must be replenished into the column, which complicates the operation process

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