Production of White Barite from Barite Concentrates of Shaking Tables by Bleaching Process after Magnetic Methods

Abstract

Market price of industrial minerals depends on the purity of products, and increases almost exponentially with the decrease in grade of coloring impurities. Therefore, this work was conducted to investigate the applicability of dry/wet high gradient magnetic separation (HGMS) and bleaching methods on the rejection rate of coloring impurities from barite ore. Experimental works were conducted on a processing plant concentrate. Both wet and dry magnetic separation processes failed in rejection of coloring impurities. Barite specifications especially for paint industry could not be satisfied due to the presence of coloring impurities in smearing form in the feed, not as free particle. But, improvement in product quality was found to be higher in wet process than that in dry one. Therefore, further cleaning of barite was applied on wet HGMS product by mineral acid (H2SO4, HCl) leaching. Acids significantly improved the quality of barite. However, bleached product quality did not meet the specifications by sulfuric acid leaching. On the other hand, saleable barite could be obtained by HCl bleaching at 15% HCl concentration for 15 minutes. Beneficiation tests stated that brightness index of barite could be increased from 68.05% to 90.12% by wet HGMS followed by HCL bleaching.