Processing of china clay by super-conducting high gradient magnetic separation

Abstract

Super-conducting high gradient magnetic separation tests on a typical china clay from the western part of India showed that the brightness of the clay can be enhanced from 72.8% to 79% ISO by suitably manipulating the process variables. Important variables studied are feed solid content, retention time, production rate (nummber of canister volumes), number of passes etc. keeping the magnetic field srength constant. The secondary magnet (wire wool matrix) and its packing volume were also not changed during these tests. A brightness of 79% was achieved with a two pass operation for 5 canister volume feed slurry having 15% solid content and with retention rime of about 20 secs. The overall clay recovery is 86%(94%_for the first pass and 92% for the second pass). Understandably, the feed solid content of second pass was lower than 15% while the iron (Fe201) could be reduced by about 55% the reduction in TiO2 was about 12% indicating that there still exists scope for removing Ti02 from this clay and enhancing brightness further. All the SC-HGMS tests were conducted at Bhabha Atomic Research Centre, Trombay, Bombay. India.