Removal of fine quartz from coal-series kaolin by flotation

• Published in: Applied clay science Vol. 143; pp. 437 - 444
• Main Authors: Bu, Xiangning, Evans, Geoffrey, Xie, Guangyuan, Peng, Yaoli, Zhang, Zungan, Ni, Chao, Ge, Linhan
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.07.2017
• Subjects: Coal-series kaolin; Depressant; Dodecyl amine; Flotation; Quartz; Dodecyl amine; Flotation; Depressant; Coal-series kaolin; Quartz
• ISSN: 0169-1317; 1872-9053
• DOI: 10.1016/j.clay.2017.04.020

Coal-series kaolin (CSK) in Xuzhou, Jiangsu Province of Eastern China was characterized by chemical analyses, X-ray diffraction (XRD) and zeta potential measurement as well as by scanning electron microscope equipped with an energy dispersive spectrometer (SEM-EDS). The authigenic ultrafine quartz grains (d90=15.8μm) closely associated with this CSK sample was the major impurity mineral, which cannot be separated from kaolin by screening and size classification process. This work investigated the separation of fine quartz from kaolin by flotation. Single mineral flotation tests indicated that effective separation of quartz from kaolin was possible with acidic pH value (pH=3), depressant of starch and collector of dodecyl amine (DDA). Rougher flotation tests of coal-series kaolin revealed that the SiO2/Al2O3 weight ratio of the concentrate was qualified for industrial applications in the presence of 160g/t starch and 100g/t DDA, at acidic pH pulp. A specially designed two-stage cleaner flotation flowsheet increased the concentrate recovery from 37.26% to 46.55% compared to a rougher flotation process. [Display omitted] •The micron quartz grains closely are associated with kaolin in this ore.•Starch can selectively depress quartz in acidic solution.•A qualified product having a proper recovery was obtained in multi-stage flotation.