Flotação de caulinita em minérios de ferro e bauxítico

• Ano de defesa: 2012
• Autor(a) principal: Otavia Martins Silva Rodrigues
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Minas Gerais; UFMG
• Palavras-chave em Português: Engenharia Metalúrgica e de Minas; Engenharia metalúrgica
• Link de acesso: http://hdl.handle.net/1843/BUOS-8TFLQR

This investigation aimed to find conditions of selectivity to separate, through flotation, kaolinite when it is present in bauxite ore and iron ore. Kaolinite is an aluminossicate very common in Brazilian ores. This thesis anticipates an industry requirement, considering the tendency towards the need of kaolinite removal from the the ores that will be mined in the next decades. Firstly, a fundamental study was done through microflotation experiments with pure samples of hematite, kaolinite and gibbsite. Four amines were evaluated as collector: dodecylamine (DDA), Flotigam EDA (EDA), Flotigam 2835 (2835), combination of amines (70DA30PA); and four ammonium quaternary salts: cetyltrimethylammonium bromide (CTAB), dodecyltrimetylammonium bromide (DTAB), cetylpiridinium chloride (CCP) and Tomamine Q-14-2 PG (AQ142). The performance of collectors was investigated at three levels of concentration, 1x10-5 mol/L, 5x10-5 mol/L, and 1x10-4 mol/L, in the pH range between 4 and 10. Corn starch and sodiumhexametaphosphate (HX), in the concentration range from 10 mg/L to 400 mg/L, were used as depressant. The fundamental study suggested the following conditions of selectivity to achieve the separation between kaolinite and gibbsite: (i) DDA in the pH range from 4 to 10, (ii)CTAB in the pH range between 4 to 10, and (iii) AQ142 at pH 10 in the presence of starch. The selective separation between kaolinite and hematite was achieved at the following conditions: (i) EDA at pH 10 in the presence of starch, (ii) DTAB in the pH range between 4 to 10, and (iii) AQ142 at pH 10 in the presence of starch. Anotherconclusion from the fundamental study was that the kinetic of flotation of the pure minerals obey the first order model. Following the fundamental study, conditions were selected to evaluate the selective separation of kaolinite from bauxite ore and from iron ore, using laboratory scale experiments. The results for bauxite, using the collector AQ142 in the presence of corn starch depressant and those with the colletor CTAB, showed a high selectivitity for the Al/Si ratio reached values close to 25. The highest recovery values, between 70% and 90%, were obtained using the colector CTAB. Despite of the low values of recovery achieved in the flotation bench scale tests with iron ore, the tests using the coletor DTAB yielded concentrates with low silica and alumina contents, approximately 1%.