The production of APT by ion-exchange technique of hydrometallurgy, are widely used by many paratungstate manufacturers because of short process, less investment and high quality. Tin belongs to harmful impurities, many kind of tungsten products have strict requirements on the level of impurities tin , such as GB10116-88 ammonium paratungstate -0 standard’s tin index is no more than 1x10-6. However, in recent years, with the increasing scarcity of wolframite resources, tin excessive problems sometimes arise in ammonium paratungstate products, which caused great difficulties to ammonium paratungstate manufacturers’ stable qualities. So research on removing tin process plays a very important role on guiding production, adjusting process, strengthen the tin control and ensure product quality.

 

Limu Sn ore area is in the northeast of Guangxi, with ​​12.9 square kilometers mining area. It is reported, Limu Sn ore tin raw material for the preparation of APT, 90% are high tin tungsten slag or high tin tungsten ore. In coarse sodium tungstate solution prepared by these materials, concentration of arsenic and tin are high and tin concentration is 0.1 ~ 0.6g / L. By ion exchange, crystallization APT, hydrochloric acid decomposition, ammonia dissolution, crystallization and a series of processes, the resulting crude product in APT Sn mass fraction (1.0 ~ 2.0) × 10-5, tungsten acid Sn mass fraction (1.0 to 3.0) × 10-6, high-APT in Sn mass fraction of 1.0 × 10-6. APT from coarse to premium APT, tungsten real yield of 86%, recovery of 98%. APT crude acid decomposition process, the tin into water-soluble chloride is removed by filtration and washed tungsten acid, in addition to tin was about 80 percent; ammonia dissolved in acid, tin and generate precipitation with ammonium tungstate separation. Chestnut wood and tin and tungsten smelting practice of classic and acid decomposition process is somewhat similar, is the use of tungsten-tin precipitation separated, thereby producing high-quality APT.

 

Someone using new technology to handle high tin, tungsten mud. Tungsten mud mass fraction of 27.46% tungsten, tin mass fraction of 3.08%. Tungsten mud after leaching by sodium hydroxide, and the resulting filtrate and the use of sulfuric acid, adjusted PH to about 9, 98% tin is precipitated hydrolysis. Then by flotation collectors, in addition to molybdenum, extraction and other processes, and finally crystallized preparation APT, the product of tin mass fraction 5.0 × 10-7.