Rejection of iron coloring impurities of quartz ore by sulfuric acid bleaching

Abstract

Quartz purification by bleaching methods has taken great interest for several decades both for conventional and high technology applications like production of optical fibers, construction of silicon cells and semiconductors, where physical methods succeeds partially. This work was performed to determine the effect of pH on the Fe rejection rate and brightness of quartz in oxidizing acid environment created by sulfuric acid. Leaching tests were conducted for 120 minutes at three different pH values (pH 0, pH 0.7, pH 1.1) in an open flow system agitated pulp condition. Sample was taken from metal loaded underflow leach liquor at 15th, 30th, 60th and 120th minutes of leaching to determine Fe dissolution rate by inductively coupled plasma mass spectrometry (ICP-MS). Quality of leached samples were determined by color analyses. Experimental works revealed that quartz-bleaching rate depends on mineralogical composition of ore. Tested ore sample could not be bleached sufficiently in oxidizing environment due to presence of hematite and mica minerals, which requires highly acid reducing condition. Copyright © IMCET 2019 International Mining Congress and Exhibition of Turkey. All rights reserved.