Kaolinite removal from bauxite by flotation

Abstract This paper presents a potential condition to separate kaolinite through flotation when it is present in bauxite ore. This research anticipates a Brazilian industry requirement, considering the tendency towards the need for aluminosilicates removal from bauxite ores, as has already occurred in China. Kaolinite is the most abundant aluminosilicate, and gibbsite is the main aluminum bearing mineral in Brazilian bauxite ores. The first step was a fundamental study involving microflotation experiments with pure samples of kaolinite and gibbsite. Ammonium quaternary salts and amines were used as the collector and corn starch as the depressant. In a fundamental study, the best conditions determined in the first step were evaluated for the flotation of kaolinite from bauxite ore using laboratory scale experiments. Tests with AQ142/starch (pH 10) and CTAB (pH 7) led to satisfactory results. In general, the highest values of alumina/silica mass ratio were obtained with AQ142/starch and the highest values of mass recovery and metallurgical recovery were achieved with CTAB.摘要 本研究提出了铝土矿中伴生高岭石（kaolinite）时，通过浮选分离该矿物的潜在工艺条件。鉴于铝土矿脱除铝硅酸盐的需求已成行业趋势（中国已率先落地此类需求），本研究旨在满足巴西铝土矿产业的此类实际要求。高岭石是巴西铝土矿中分布最广的铝硅酸盐矿物，而三水铝石（gibbsite）则是该类矿石中主要的含铝矿物。研究的首要环节为基础研究：以高岭石与三水铝石纯样开展微浮选实验，选用季铵盐与胺类作为捕收剂，玉米淀粉作为抑制剂。在此基础研究中，本研究通过实验室规模实验，对第一步确定的最优工艺条件进行验证，以实现铝土矿中高岭石的浮选脱除。采用AQ142/淀粉体系（pH值为10）与CTAB体系（pH值为7）开展的浮选实验均取得了理想效果。总体而言，采用AQ142/淀粉体系时可获得最高的铝硅质量比，而CTAB体系则实现了最高的质量回收率与金属回收率。