Sinergismo de tiocoletores e óleo diesel na flotação de ZnS e PbS em minério willemítico de Vazante-MG
Synergism of thiocollectors and diesel oil in the flotation of ZnS and PbS in willemitic ore from Vazante-MG
Fábio de São José; Kennedy da Silva Ramos; Carlos Alberto Pereira
Resumo
A concentração de minerais sulfetados por flotação lida com propriedades intrínsecas dos mesmos, especialmente a alta reatividade superficial que determina a forte oxidação da superfície mineral. Pesquisou-se a recuperação coletiva de sulfetos de Zn e Pb, presente em minério willemítico, para permitir a recuperação do zinco em duas rotas, uma a partir da willemita e outra da esfalerita, além de coprodutos como chumbo e prata. Explorou-se combinações de reagentes com foco no uso simultâneo de coletores e óleo diesel, figurando a chamada flotação extensora convencional. Como resultado destacou-se a recuperação de zinco de 95,33% e teor de 12,96% a partir da mistura de amil xantato (150 g/t), óleo diesel e MIBIC. Destacou-se também a importante participação do sulfeto de sódio como sulfetizante e amenizador da oxidação mineral, porém dosagens do sulfetizante com deslocamento do pH acima de 11 resultaram em queda na recuperação de zinco. Os potenciais eletroquímicos foram medidos e quando estes parâmetros se situaram abaixo de -25 mV, mais altos valores de recuperação de Zn (95,33%), Pb (54,14%) e Ag (79,00%) foram obtidos, devido aos menores níveis de oxidação da polpa com esta faixa de potencial eletroquímico.
Palavras-chave
Abstract
The concentration of sulfide minerals by flotation deals with the intrinsic peculiarities of these materials, especially its high surface reactivity that takes the strong oxidation. This research studied the lead and zinc sulfides recovery, present in willemitic ore, a zinc silicate ore resulting from metamorphism of hydrated hemimorphite and sphalerite, and allowing the existence of two and economically routes to obtain zinc (from sulfides and silicates forms) as well as lead and silver how coproducts. Were explored combinations of reagents (dispersants, activators, and collectors) in an attempt to raise the metallurgical recovery of zinc, lead, and silver by ore flotation. As a result, 95.33% of recovery containing 12.96% of zinc was reached involving the mixture of amyl xanthate (150 g/t), diesel oil, and methyl isobutyl carbinol, suggesting mechanisms of extensor conventional flotation and synergism of reagents. Sodium sulfide can be used as a pH modulator besides contributing to the “re-sulphidation” of sulfides. But the use of sodium sulfide above pH 11 makes this reagent a depressant for sulfides, resulting in a decrease of recovery. The electrochemical potential of the pulp became more negative, i.e., Eh above -25 mV, was linked to largest recoveries of Zn (95.33%), Pb (54.14%), and Ag (79.0%) obtained in the flotation tests, as responses to the lower levels of pulp oxidation.
Keywords
Referências
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Submetido em:
24/01/2024
Aceito em:
28/07/2024
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