ABSTRACT Mineral flotation is a wet concentration operation that has a differentiating effect dependent on the surface properties of the minerals. Water quality is integral to the phosphate ore flotation, since the presence of certain ions in the solution can compromise the effectiveness of the operation. The objective of this study was to compare the effectiveness of phosphate ore flotation (dispersed air) before and after effluent treatment using coagulation, flocculation and dissolved air flotation (DAF) techniques. The mineral flotation tests were performed for new water (NW) and three effluents tailing dams (TD), simulated effluent with high concentrations of calcium and magnesium ions (SE) and simulated effluent after DAF treatment (SEDAF). The simulated effluent underwent two stages of aggregation followed by DAF for cation removal. The results showed that the proposed technique removed 91.6% of magnesium and 66.4% of calcium from the original simulated effluent (SE). The SEDAF presented better average values of mass recovery, content, and recovery of P2O5, confirming the effectiveness of the removing ions suggested as deleterious for mineral flotation. The flotation performance of the DAF-treated effluent was comparable to that of new water. This study underscores the significance of water quality management in optimizing mineral flotation processes. minerals dispersed coagulation (DAF techniques NW (NW TD, TD , (TD) SE (SE SEDAF. . (SEDAF) removal 916 91 6 91.6 664 66 4 66.4 SE. content P2O5 PO P O DAFtreated treated processes (TD (SEDAF 9 91. 66. P2O

Essa investigação avaliou o efeito de depressores para dolomita na flotação de zinco, a fim de aumentar tanto a recuperação quanto a seletividade. Os reagentes estudados foram: uma emulsão de amina (Clariant Flotigan 2835-2L), óleo diesel e MIBIC, nas proporções 1,0; 0,16 e 0,4 como coletor e espumante; solução de sulfeto de sódio e barrilha como agente ativador e modificador de pH, respectivamente; silicato de sódio como agente dispersante e como depressores: silicato de sódio, dextrina, dicromato de potássio, tanino, amido e carboximetilcelulose (CMC). As etapas de dispersão, sulfetização e flotação de willemita foram investigadas. Esse trabalho foi desenvolvido em escala de laboratório e apresentou, entre outros resultados, um bom desempenho da carboximetilcelulose e amido como depressores da ganga dolomítica na flotação do minério de zinco willemítico.

This research addressed the effects of depressants on willemite flotation, in order to increase both zinc recovery and selectivity. The reagents were: an amine emulsion (Clariant Flotigan 2835-2L), diesel oil and MIBIC in the proportions of 1.0, 0.16 and 0.4 as the collector and frother; a sodium sulfide and sodium carbonate solution as the activator and pH modifier, respectively; sodium silicate as the dispersant agent; and as the depressant: sodium silicate, dextrin, potassium dichromate, tannin, starch and carboxymethylcellulose (CMC). The steps of dispersion, sulfidization and willemite flotation were investigated. This work was conducted on laboratory scale and showed, among other findings, that a good performance could be obtained using carboxymethylcellulose and starch as a dolomitic gangue depressant in the flotation of willemite zinc ore.

O beneficiamento dos minérios fosfáticos com ganga silicatada e carbonatada é estritamente necessário para aumentar a produção de concentrados fosfáticos e para suprir a demanda nacional de fertilizantes. Visando a processar esses minérios, esse trabalho estudou, através de testes de microflotação e medidas de potencial zeta, o efeito do oleato de sódio, do amido de milho e da carboximetilcelulose (CMC) na superfície dos minerais puros originários do minério sílico-carbonatado de Catalão/GO. Os resultados obtidos mostraram a possibilidade de separação seletiva da apatita, por flotação direta em pH igual a 9, usando-se oleato de sódio como coletor, na ausência de depressores, o que seria inviável industrialmente. Tanto a CMC como o amido deprimem a dolomita, mas não são seletivos, pois deprimem, também, a apatita. O amido apresenta ação depressora sobre a apatita mais forte que a CMC.

The processing of phosphate ores containing silicates and carbonates in the gangue is strictly necessary to increase phosphate rock production to meet the Brazilian demand for fertilizers. Aiming at the processing of these ores, this investigation addressed, via microfl otation and zeta potential determinations, the effect of sodium oleate, corn starch and carboxymethylcellulose (CMC) on the surfaces of pure minerals from the Catalão/GO silicate-carbonate deposit. The results suggested the possibility of selective apatite concentration via direct fl otation at pH = 9, using sodium oleate as collector, in the absence of depressants; a route that would be industrially unfeasible. Both, CMC and starch, act as dolomite depressants, but the action is not selective, for apatite is also depressed by these reagents. Starch is a stronger apatite depressant than CMC.