Low Energy Consumption Tungstate Extraction Method

With the development of modern science and technology, higher requirements are put forward for the preparation of tungsten, tungsten alloys and tungsten compounds. Tungstate is an important intermediate material in tungsten smelting, and its preparation and technological research have important value and significance.

Ammonium paratungstate and ammonium metatungstate are the most common tungsten compounds in tungsten production. Among them, ammonium paratungstate is prepared by ion exchange or evaporation crystallization after extraction, while ammonium metatungstate is prepared by solvent extraction, ion exchange, neutralization, electrodialysis and nanofiltration. The large particle size of the product is not conducive to the performance improvement of subsequent products, and evaporative crystallization requires high energy consumption and high manufacturing cost.

In view of this, some scholars have developed a new scheme for tungsten purification. Using crude sodium tungstate solution or ammonium tungstate solution as raw material, using tungstate extraction method, and the crystallization and dissolution process of sodium tungstate or ammonium tungstate was reduced. Ultrafine or nanometer tungsten powder was prepared. The process was roughly as follows:

The crude sodium tungstate solution (0.3 mol of tungstate) obtained by ion exchange was mixed with 0.16 g oleamine and water to obtain 200 ml A liquid initial solution, and then added dilute sulfuric acid to adjust the PH value to 5.0 to form A liquid; 2.1 mol methylamine was dissolved in water to obtain 700 ml B liquid; A liquid and B liquid were added into the reactor by parallel feeding method, and the reaction temperature was maintained at 50 ℃ for 6 h, and stirred. The reaction products were separated by centrifugal filtration to obtain tungstate filter cake. The impurities in tungstate filter cake were removed by water washing, and the wastewater was centralized treated. Finally, tungstate powder was obtained by drying in air at 70 ~C for 12 hours.

With the above method, it is easy to realize the controllable production of tungstate granularity, stable and continuous production of product quality, simple, safe and reliable operation, low production cost and high yield. The prepared tungstate products have stable quality, good fluidity, good dispersion, high chemical purity, uniform particle size distribution, hexagonal prism shape and average particle size of 1-10 um, which are suitable for preparing ultrafine tungsten powder, tungsten carbide, tungsten alloy powder, etc.

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