Clatratos na flotaçao catiônica reversa de minérios de ferro

• Ano de defesa: 2014
• Autor(a) principal: Maria Auxiliadora Mendes Aguiar
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Minas Gerais; UFMG
• Palavras-chave em Português: Materiais e de Minas; Engenharia Metalúrgica; Engenharia metalúrgica
• Link de acesso: http://hdl.handle.net/1843/BUBD-9VNHA5

Amines adsorbs at the solid-liquid interface when added to aqueous solution which contains quartz particles under certain pH conditions, rendering these particles hydrophobic. However, this hydrophobicity may be affected by the addition of starch into the system, which is capable of adsorbing mutually with amine due to the formation of a helical complex between the reagents, called clathrate. Therefore, the quartz particles reacquire a hydrophilic surface since the amine is hidden by the starch envelopment. There are few studies on starch-surfactant interaction in the reverse cationic iron ore flotation. Aiming to study the conditions involving the formation of these complexes, microflotation and electrophoresis experiments were conducted with hematite and quartz and the reagents etheramine (frother and quartz collector) and corn starch and Amidex 4001 (hematite depressants). It was observed that the corn starch promoted a decrease in the flotability of quartz, dropping from 95% to 35% as amine dosage was increased. Amidex did not show this trend at any condition investigated. Quartz depression was favored by the increase in the dosage of both amine and corn starch and by alcaline pH conditions. The electrophoreses experiments for zeta potential measurements were conducted in two stages. In the first stage, the quartz particles were studied in the presence of an indifferent electrolyte and amine at the concentrations of 0 mg/L, 50 mg/L e 80mg/L. The isoelectric point (IEP) was achieved at pH values 2.0, 6.0 and 8.5 respectively. In the second stage, experiments were conducted with amine and corn starch at 80 mg/L and evidences of the formation of clathrates were observed. In these conditions, higher zeta potential values were obtained when compared with the results obtained for quartz with amine only.