The Removal of Iron From Hard Pulverised Kaolin by Dry High–Gradient Magnetic Separation
Deposits of hard kaolin are abundant in China, with kaolin content in the ore exceeding 95%. It is, however, rather difficult to remove iron from the ore. It was demonstrated that wet high–gradient magnetic separation is very efficient in removing the iron compounds from kaolin. For hard kaolin, however, dry high–gradient magnetic separation (HGMS) may be more suitable. To this end, we have developed a new type of dry HGMS device for laboratory use. The separation performance of the device was tested as a function of the iron concentration in the ore, gas velocity, magnetic induction and the intensity of the vibrating current. The following results were achieved: for sample no. 1 of hard kaolin, the content of Fe2O3 was reduced from about 2.20% to .082%, with the yield of the concentrate of 86.5%. For no. 2 sample of hard kaolin, the content of Fe2O3 was reduced from about 0.60% to 0.48%, with the yield of the concentrate 83.15%. The removal of the iron oxide from hard kaolin by dry HGMS proved to be feasible. Industrial–scale dry HGMS device was built and installed at a mine at the end of 1993.