Hematite and quartz microflotation using millet starch as depressant

Abstract Brazil is among the world's largest iron ore producers. The standard concentration method is reverse cationic flotation using amines, and their derivatives, such as quartz collector and corn (as either grits, flour, or starch) as the hematite depressant. Corn is considered cheap, abundant, and available all around the country. However, its demand has been abruptly increasing over the last few years, mainly due to the emerging of new attractive markets, such as ethanol production. In order to propose a feasible replacement for corn, hematite and quartz samples from the Brazilian Iron Quadrangle were tested in a modified Hallimond tube using millet starch as depressant for the first time (corn and sorghum starch were used as benchmark). Tests were carried out with four different depressant dosages and four different pHs, all in triplicate. It was possible to reach quartz floatability above 98% and hematite depressability above 93% for millet and sorghum starches. This fundamental study shows that replacing corn with millet poses a real opportunity to reduce operational costs.

摘要：巴西是全球最大的铁矿石生产国之一。当前主流的铁矿石富集方法为采用胺类及其衍生物作为石英捕收剂、以玉米（包括玉米颗粒、玉米粉或玉米淀粉）作为赤铁矿抑制剂的反阳离子浮选法。玉米因价格低廉、储量充足且在巴西全境均可获取而被广泛应用。然而近年来，乙醇生产等新兴高潜力市场的崛起导致玉米需求陡然攀升。为探寻可行的玉米替代方案，本研究首次采用小米淀粉作为抑制剂，对取自巴西铁四角地区（Iron Quadrangle）的赤铁矿与石英样品开展改进型哈里蒙德管（Hallimond tube）浮选试验，同时以玉米淀粉与高粱淀粉作为参比基准。试验设置了4种不同的抑制剂添加量与4种不同pH值条件，所有试验均平行重复3次。结果表明，小米淀粉与高粱淀粉均可实现石英上浮率超过98%、赤铁矿抑制率超过93%的浮选效果。本基础性研究证实，以小米替代玉米具备切实降低运营成本的潜力。