Tungsten ore low, must be integrated mineral-rich concentrate to a smelting raw material. According to the type of tungsten ore dressing into wolframite and scheelite mineral beneficiation two types. Present mining to wolframite quartz vein type, accounting for the amount of ore taken out more than 90%. Tungsten ore dressing methods mainly hand-selected, HM election, re-election, flotation, magnetic separation and electrostatic separation methods such as.
Wolframite in order to re-election dominated by flotation mainly scheelite. Most of our wolframite is easy to choose the type of ore, while the composition of scheelite ore complex, and mostly of refractory ore, coupled with low grade, so not a lot of development. In addition, tungsten oxide minerals such as tungsten China currently not recycled. China’s tungsten ore dressing and processing plant started in 1952 a large-scale factory in Dajishan Tungsten establish 125t / d of gravity concentration plant, the late 50s, former Soviet Union Mechanobr Research and Design Institute for the down hill , West Mountain and hilly Miyama tungsten designed three large-scale tungsten ore processing plant put into operation one after another. 40 years in the production practice constantly sum up experience, and absorb foreign advanced technology dressing, through continuous improvement, so that beneficiation process is improving daily, processing technical and economic indicators have reached the world advanced level.
Nanchang representative non-ferrous metals such as tungsten ore beneficiation company targets, despite nearly 10 years in the annual decline in ore grade, the tungsten recovery remained at 84% or more of the high concentrate grade (WO3) 66.7 % ~ 68.9% (up to 12 tungsten national standards: WO3 content is not less than 65%), ore grade (WO3) 0.25% ~ 0.27%, tailing grade (WO3) 0.036% ~ 0.046%. Tungsten smelting and fire refining method and two kinds of water law. The use of wolframite concentrate or smelting scheelite concentrate, but different smelting process, so both wolframite deposit, there scheelite, we must each ore body, each calculated reserves. When the ore wolframite, scheelite coexist together, to elect a black tungsten concentrate and scheelite concentrate for smelting, respectively. The smelting of mineral raw materials as tungsten tungsten ore concentrates, containing WO3 should meet or greater than 65%. The pyrometallurgical into tungsten alloy (with W>70 or>65%) by Water Act, a positive tungsten smelting sodium, calcium APT or tungsten, etc.. Finally, further processed into tungsten trioxide (containing WO3>=99.9%), then reducing agent (usually hydrogen) is reduced to tungsten powder (with W>=99.9%) and so on. Tungsten is recovered from scheelite ore concentrates, or other tungsten concentrates which may, or may not contain scheelite in the form of sodium tungstate and in yields up to 99.5 percent or more by a process in which ground ore substantially below 200 mesh in particle size is first added to a 50 percent sodium hydroxide solution while being agitated to such an extent that the resulting mixture becomes a semi-solid as the temperature is raised above 80°C.
The semi-solid is then baked at 135 to 145°C for about 1 to 2 hours, followed by adding sufficient water to the semi-solid to form a slurry having a sodium hydroxide concentration below 6 molar, separating the causticinsoluble sludge from the slurry and washing the sludge with a dilute sodium hydroxide solution to remove residual sodium tungstate.