THE NEW TECHNOLOGY OF ENRICHMENT OF A FINE LOW-GRADE TUNGSTEN FROM COMPLEX MULTI-METALLIC ORE

摘要

Shizhuyuan is a world-class polymetallic deposit of WO_3, Mo, Bi and CaF_2, with its ore being highly difficult to separate. Thereby, it has been a pending problem in mineral processing technology for many years. At present, for fine low-grade complex ore, the recovery of tungsten is less than 65 per cent. This paper presents a new technology of recovering fine low-grade tungsten ores, which includes scheelite flotation, magnetic separation and wolframite flotation. The distribution rates of WO_3 in fine tungsten minerals (90 per cent with particle sizes less than 0.074 mm) are as follows: scheelite 82.69 per cent, wolframite 13.85 per cent and tungstite 3.46 per cent. The scheelite rough concentrate is floated with efficient collector, followed by scheelite heating concentration, hence a scheelite concentrate is obtained. By high intensity magnetic separation, a wolframite rough concentrate is recovered from the tailing of scheelite flotation. Finally, the wolframite rough concentrate is treated by wolframite flotation with chelating collector, finally a wolframite concentrate is obtained. For the feed assaying 0.26 per cent WO_3, a scheelite concentrate assaying 74.57 per cent WO_3 and a wolframite concentrate assaying 28.88 per cent WO_3 can be obtained, the recoveries of the two concentrates are 69.47 per cent and 8.08 per cent respectively, the total recovery of scheelite and wolframite is 77.55 per cent. The processing capacity of industrial test has reached 258.25 t/d, the grade of industrial test feed is 0.44 per cent WO_3, and the distribution rates of tungsten minerals in raw ore are: scheelite 52.38 per cent, iron-containing scheelite 7.14 per cent, wolframite 40.48 per cent. When the grinding fineness being about 82 ～ 85 per cent -0.074 mm, the statistical index for continuous 11 days of industrial test are as follows: the scheelite concentrate grade is 68.20 per cent WO_3, the wolframite concentrate grade is 37.54 per cent WO_3, the recovery of above two concentrates are 55.32 per cent and 21.41 per cent, respectively, the total recovery of scheelite and wolframite is 76.73 per cent.