Research direction and technical progress of green tungsten metallurgy

Although a world leader in tungsten metallurgy,the acid and alkali leaching- chemical purification- ammonium salt transformation wet processing technology applied in China tungsten industry for hundreds of years failed to achieve zero waste water discharge due to the Na⁺ and Cl^- problems. The pyrogenic method for making tungsten carbide directly from tungsten concentrates and the process for making tungsten carbide or metallic tungsten directly by fused salt electrolysis have some insurmountable faults in metal purification and the separation of impurities. One of the bottle-neck problems is the waste acid and alkali water discharge. The results shows that, comparing with traditional technological process, the total yield of WO 3 is 98.1 % , up 2.6 %. The cost has been reduced by 30 % in this process. The technology has realized green scheelite smelting with acid and alkali-free with no waste water discharge.