Polímeros depressores na flotação de minério de ferro

Abstract

Iron ore export plays a relevant role in the Brazilian trade flow. A significant fraction of the production comes from flotation. All Brazilian concentrators use starch as depressant. Other polymers are being investigated and used in the flotation of other ores. This study evaluates the application of carboxymethylcellulose, lignosulfonate, humic acid, guar gum, and polyacrylamides in iron ore flotation. A literature reviewaddressing iron ores, iron ores flotation, and relevant aspects regarding polymers use in the mineral industry was performed. Zeta potential determinations and microflotation experiments were the tools employed aiming at evaluating the polymers adsorption onto quartz and the floatability of both minerals. Results of laboratory flotation testsshowed that only two polymers reach the same performance as starch. Both are polymers presenting the glucopiranose ring. Guar gum yielded the best results, performing satisfactorily even at lower dosages. The use of polymer mixtures led to promising results, indicating that they could be used as an alternative. The reagents yielding the best performances present the same effect on hematite and quartz floatability and zeta potential, indicating similarity in the adsorption mechanism andaction as depressant