Recuperação de níquel e outros metais a partir de diferentes fontes (rejeitos minerais de processo industrial e pentlandita '(Ni,Fe)IND. 9' 'S IND. 8' ) mediante lixiviação ácida e bacteriana
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Data
2010-07-15
Autores
Blandón, Nury Alexandra Muñoz [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Uma possibilidade para a recuperação de metais a partir de minerais com baixos teores ou de rejeitos industriais é a utilização da lixiviação com micro-organismos. A biolixiviação é o processo de oxidação bacteriana de sulfetos metálicos contendo metais de valor (por exemplo, níquel, cobre ou zinco), os quais são liberados para a solução, seguida da recuperação por técnicas metalúrgicas convencionais. Estudos de biolixiviação de concentrados de sulfetos minerais em tanques agitados e, sobretudo em pilhas, têm sido desenvolvidos em escala piloto e comercial. Entretanto, poucos trabalhos têm sido realizados sobre o aproveitamento de rejeitos minerais de processos convencionais, tais como flotação ou fusão em forno “flash”, por rotas biotecnológicas. O objetivo deste trabalho foi recuperar níquel e cobre de rejeitos industriais, provenientes de processo de flotação e de fusão, utilizando bactérias, especialmente da espécie Acidithiobacillus ferrooxidans ou pelo uso de soluções ácidas, em escala de laboratório. Também foram realizados experimentos de biolixiviação de um sulfeto de níquel (pentlandita) para avaliar o processo de solubilização do metal. Conjuntamente, outros experimentos foram realizados com a finalidade de se obter novas linhagens isoladas a partir destes rejeitos minerais. Suas diferenças fisiológicas foram avaliadas. A partir dos experimentos com os rejeitos encontrou-se que com a escória foi possível obter 13% de níquel e 8 % de cobre em solução após 14 dias de lixiviação biológica. Com soluções ácidas, em pH 0,5 e 1,0, as recuperações foram de 56% de níquel e 24% de cobre em pH 0,5 enquanto que em pH 1,0 as concentrações foram de 21% e 12% de niquele e cobre, respectivamente. Para a recuperação de níquel e cobre deste rejeito sugere-se a lixiviação ácida e não bacteriana. Com a lama as porcentagens...
Bacterial leaching is a feasible to recover metals from minerals with low grade or from mine wastes using microorganisms. The bioleaching process is the bacterial oxidation of valuables metals bearing sulphide minerals (e.g. nickel, copper or zinc), which are released to the solution, followed by conventional recovered by metallurgical techniques. Studies on bioleaching of sulphide minerals concentrates in stirred tanks and, particularly, in heaps, have been developed on pilot and commercial scales. However, few studies have been undertaken on using of mineral wastes from conventional processes such as flotation or flashing smelting through biotechnological routes. This work aims at recovering nickel and copper from industrial wastes such as flotation tailings and slag using bacteria, especially Acidithiobacillus ferrooxidans species, or using acid solutions at laboratory scale. Experiments were also accomplished for nickel sulfide bioleaching to evaluate the metal dissolution process, for comparison purpose. Other experiments were also carried out to obtain new strains isolated from mineral waste to study the physiological differences between them. After 14 days of bioleaching of slag it was possible to extract 13% of nickel and 8% of copper in solution while with acid solutions the extractions were 56% of nickel and 24% of copper at pH 0.5 and 21% and 12% at pH 1.0, respectively. For the metals solubilization from the slag it is suggested the acid leaching instead of bioleaching. With the flotation tailings the recoveries of nickel and copper were 23% e 16% at pH 0.5 or 1.0 while after 14 days with bioleaching the concentrations in solution were 46 % and 17% for nickel and copper. These results show that the flotation tailings can be treated with biological leaching for a higher recovery of metals. The studies of nickel sulfide bioleaching with different bacterial species reached only... (Complete abstract click electronic access below)
Bacterial leaching is a feasible to recover metals from minerals with low grade or from mine wastes using microorganisms. The bioleaching process is the bacterial oxidation of valuables metals bearing sulphide minerals (e.g. nickel, copper or zinc), which are released to the solution, followed by conventional recovered by metallurgical techniques. Studies on bioleaching of sulphide minerals concentrates in stirred tanks and, particularly, in heaps, have been developed on pilot and commercial scales. However, few studies have been undertaken on using of mineral wastes from conventional processes such as flotation or flashing smelting through biotechnological routes. This work aims at recovering nickel and copper from industrial wastes such as flotation tailings and slag using bacteria, especially Acidithiobacillus ferrooxidans species, or using acid solutions at laboratory scale. Experiments were also accomplished for nickel sulfide bioleaching to evaluate the metal dissolution process, for comparison purpose. Other experiments were also carried out to obtain new strains isolated from mineral waste to study the physiological differences between them. After 14 days of bioleaching of slag it was possible to extract 13% of nickel and 8% of copper in solution while with acid solutions the extractions were 56% of nickel and 24% of copper at pH 0.5 and 21% and 12% at pH 1.0, respectively. For the metals solubilization from the slag it is suggested the acid leaching instead of bioleaching. With the flotation tailings the recoveries of nickel and copper were 23% e 16% at pH 0.5 or 1.0 while after 14 days with bioleaching the concentrations in solution were 46 % and 17% for nickel and copper. These results show that the flotation tailings can be treated with biological leaching for a higher recovery of metals. The studies of nickel sulfide bioleaching with different bacterial species reached only... (Complete abstract click electronic access below)
Descrição
Palavras-chave
Biotecnologia, Lixiviação bacteriana, Leaching
Como citar
BLANDÓN, Nury Alexandra Muñoz. Recuperação de níquel e outros metais a partir de diferentes fontes (rejeitos minerais de processo industrial e pentlandita '(Ni,Fe)IND. 9' 'S IND. 8' ) mediante lixiviação ácida e bacteriana. 2010. 127 f. Tese (doutorado) - Universidade Estadual Paulista, Instituto de Química de Araraquara, 2010.