タングステン鉱の脱砒焙燒に関する研究
1956 年 72 巻 812 号 p. 75-80
詳細
1956 年 72 巻 812 号 p. 75-80
We investigated on the elimination of arsenic from scheelite by roasting which iscommonly found in tungsten ore and detested as an impurity that decreases the recovery of tungsten from alkali leach solution and lowers the quality of finished product.
Following results were obtained.
1) The roasting in oxidizing atmosphere to volatilize as arsenic trioxide was notcompletely successful, because unvolatile arsenate was partly formed. Dearsenizing ratio was 50-70% at 700-1000°C for 1 hr.
2) The roasting in nonoxidizing atmosphere (N2, CO2, SO2) to volatilize mainly as arsenic sulphide was very effective. Dearsenizing ratio was almost 100% at 900-1000°C for 1hr.
3) The fluosolid roasting process was applied. The very fine flotation concentrate (-325 mesh) was fluidized together with larger particles of pyrrhotite (60-100mesh) which was used to make stabilized bed and SO2 atmosphere. The cinder of concentrate was caught in the cyclone as carry over and pyrrhotitee was discharged as over flow. Dearsenizing ratio was90% at 800-900°C.
The coarse jig concentrate (-100mesh) was fluoroasted in the charcoal producer gas. By the roasting of 1000°C for 20 minutes arsenic content decreased from 0.13% to 0.02% and it was superior to the oxidizing roasting.
