Ammonium Paratungstate Purification by Extraction Method

Tungsten is an important strategic metal resource. Ammonium paratungstate/tungsten trioxide is an important chemical product of tungsten. Qualified products of ammonium paratungstate and tungsten oxide are produced in tungsten smelting process, or waste materials of ammonium paratungstate and tungsten oxide are collected.

At present, ammonium paratungstate is mostly leached by high concentration ammonia at 120-160 ~℃ stirring for 1-4 hours to completely dissolve; some enterprises will promote the decomposition of ammonium paratungstate in the future, even through high-temperature roasting to obtain tungsten oxide, then ammonia solution to obtain ammonium tungstate solution; some enterprises will use strong alkali such as sodium hydroxide to dissolve ammonium paratungstate and obtain sodium tungstate solution to regenerate. To the solution of ammonium tungstate, the process is complex and the cost is high.

In view of the shortcomings of the existing technology, some enterprises adopt extraction method to purify ammonium paratungstate. The specific steps are as follows:

(1) The organic phase is obtained by mixing extractant, regulator and solvent, and the volume ratios of extractant, regulator and solvent are respectively determined.
0.5-85%, 0-70% and 0-95%.

(2)Ammonium paratungstate (100g), 500-700 mL steps (1) were mixed with acid with 50-80 mL concentration of 0.1-18 mol/L, and stirred for 1-20 minutes at 0-100 ℃ to make ammonium paratungstate completely dissolved, resulting in water and oil phase mixtures after dissolution.

(3)Adding regenerant of 200-300 mL concentration of 0.1-20 mol/L to the mixture obtained by step (2) stirring at room temperature for 10-20 minutes to regenerate the organic phase and obtain tungstate solution at the same time.

(4)Separation step (3) The organic phase and tungstate solution obtained are returned to the dissolution process, and the tungstate solution is used as the product.

By adjusting the dissolution reaction system to be acidic, the process realizes the dissolution of ammonium paratungstate into tungstate and the regeneration of organic phase, which can be reused. The process flow is short, the energy consumption is low, the time consumption is short and the operation is simple.

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