Reduction of Magnetic Discoloring Mineral Impurities from Kaolin Clay Using High Intensity and High Gradient Magnetic Separators
This paper deals with the investigation carried out on reduction of magnetic discolouring mineral impurities present in kaolin clay and to improve its brightness by using high intensity and high gradient magnetic separators. The results indicate that in presence of wash water the non-magnetic product obtained at a magnetic intensity of 1.2 Tesla (T) by using Wet High Intensity Magnetic Separator (WHIMS) contains 0.98 % Fe2O3 with brightness of 78.8 % and at 1.6 T by using High Gradient Magnetic Separator (HGMS), non-magnetic product obtained contains 0.6 % Fe2O3 with 81 % brightness from a sample containing 1.6 % Fe2O3 with 75.68 % brightness. This product is suitable for filler industrial application.
1. Introduction
Kaolinite occurs in sub-µm size and white in colour and its chemical composition varies from 46.54 % SiO2 and 39.50 % Al2O3 with 13.96 % H2O. The kaolinite samples are known as platelets minerals, which originally exhibit white colour with high brightness, but it mainly contains various amount of magnetic discoloring elements/impurities, such as anatase (TiO2), mica
[{K (Al, Fe+3)} 2 Al2Si3O4], iron oxide (Fe2O3), goethite (FeOOH), lepidocrocite (γ-FeOOH), hematite (Fe2O3), magnetite (Fe3O4), Fe-stained rutile/ilmenite, pyrite (FeS2) with a magnetic susceptibility of...