Production of Ammonium Paratungstate by Zero Pollution

In the prior art, the preparation of ammonium paratungstate industrial process from tungsten mineral raw materials by caustic soda or soda decomposition to obtain crude sodium tungstate solution; purification by solution ion exchange or solvent extraction transformation to obtain the pure ammonium tungstate solution; then through evaporation and crystallization, APT products.

Recently, some scholars have innovated a new method of making ammonium paratungstate, which is different from the traditional method. The main contents are as follows:

1) The raw materials and ingredients of tungsten minerals are fined, and the raw materials are prepared by mixing.

2) Roasting raw material, getting clinker, and crushing and grinding the clinker;

3) Leaching clinker with ammonium carbonate system, ammonium carbonate - ammonium bicarbonate system, ammonium carbonate - ammonia water system and ammonium carbonate - ammonium hydrogen carbonate - ammonium tungstate system;

4) The leached slurry is separated by solid-liquid separation and washed by the slag phase to obtain the crude ammonium tungstate solution and the leached residue, and part of the leached residue is returned to the step 1 for raw material configuration and the remaining part is stored;

5) Crude ammonium tungstate solution purification impurity;

6) After purification, APT was precipitated by evaporation crystallization, and ammonia and carbon dioxide gas were obtained at the same time.

7) The crystallized slurry is separated by liquid and solid, and the crystallization mother liquid and solid phase are obtained. The solid phase is washed by the water solution. After the drying, the APT product is obtained.

8) The ammonia and carbon dioxide obtained from the crystalline mother solution are returned to step 3 together, and the clinker is leached after the supplement of the lost ammonium carbonate.

The method has the advantages of simple process flow, convenient operation, low production cost, no waste water discharge and environmental pollution reduced to a minimum, and is a brand new process for preparing APT. Eliminating the transformation step of sodium tungstate solution, which produces a large amount of wastewater, directly obtains the ammonium tungstate solution, which fundamentally eliminates the waste water discharge in the APT production process and realizes the recycling of auxiliary materials and solutions.

• < Prev
• Next >