The purity of a quartz ore is relatively low at a SiO2 content of 97.18%, and the main impurity in the ore is Fe, Al, and Ca bearing minerals. The main component in an industrial waste bacteria (WJ) is polysaccharides, which may be used as depressors for inhibiting iron minerals in quartz flotation. Moreover, WJ belongs to microbial inhibitors because it is mainly composed of bacteria. As a result of this study, a concentrate grade of 99.88% at recovery over 80% was obtained under the condition of 2000 g/Mg WJ dosage, a grinding fineness of 70%-0.074 mm, pH 11.7, 400 g/Mg CaCl2, and 800 g/Mg NaOL in the flotation experiments for the quartz ore. Moreover, a SiO2 grade of 99.97% at a recovery of 68.85% was obtained at an acid dosage of 40 kg/Mg by using mixed acid of H2SO4, HCl, HNO3, and HF in mass ratios of 20%, 30%, 20%, and 30%, respectively, in subsequent acid leaching of the quartz flotation concentrate. Zeta potential analysis before and after the interaction of quartz and hematite with WJ showed that WJ increased the zeta potential of hematite significantly but had little impact on the zeta potential of quartz, indicating stronger adsorption of WJ on hematite than on quartz. FTIR analysis showed that there exist not only-COOH,-CH2-, and-CH3, which are the functional groups of starch but also NH2 and-C=O-NH-in WJ. The NH2 and-C=O-NH-in WJ are the important groups for adsorption, so the depressing effect on hematite was better for WJ than starch.

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