Atividade microbiana nas transformações dos óxidos de ferro para o branqueamento de minerais de argila
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Data
2002-02
Autores
Silva, Silas Macedo [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Este trabalho foi conduzido no laboratório de geoquímica do Departamento de Recursos Naturais da FCA-UNESP LAGEADO, Botucatu(SP). Utilizou-se como material básico de estudo, a argila do tipo caulinita, obtida na região de Botucatu(SP). Vários experimentos foram conduzidos com o objetivo de determinar os níveis ideais para os parâmetros que pudessem influir no branqueamento do caulim como a concentração de sacarose, relação C:N:P, relação água:substrato, temperatura, além da determinação da natureza biológica do processo. A taxa de branqueamento determinada em cada experimento foi caracterizada, em função de uma escala de branqueamento elaborada especificamente para este trabalho. Antes e após o bioprocessamento, o material de estudo foi submetido às análises de Espectrometria de Absorção Atômica (AAS), determinação da superfície específica e volume de poros (BET) e difratometria de raios-X. Os resultados obtidos indicaram que a faixa ideal quanto a concentração de sacarose foi de 4,0% a 5,5% em relação ao substrato. A relação C:N:P que promoveu um melhor resultado no processo foi igual a 250:1:0,2, reduzindo o tempo para início do processo de branqueamento. A relação água:caulim situada entre 3,0:1 e 2,0:1 mostrou ser a faixa ideal para o desenvolvimento do processo estudado. Quanto à temperatura, o que se observou foi um melhor desempenho quando a mesma foi mantida em 30oC sendo que, à 35oC os resultados foram similares. Abaixo de 30oC e acima de 35oC o processo de branqueamento é drasticamente afetado. A comprovação da natureza biológica do processo, também foi verificada experimentalmente. As análises de Espectrometria de Absorção Atômica (AAS), mostraram uma redução de mais de 40% no teor de ferro contido no material original. A difratometria de raios-X mostrou que o branqueamento biológico... .
This work was carried out at the laboratory of geochemical of the Departmento de Recursos Naturais of FCA-UNESP LAGEADO, Botucatu(SP). It was used as basic material of study, the clay of the type kaulinite, obtained in the area of Botucatu(SP). Several experiments were driven with the objective of determining the ideal levels for the parameters that could influence in the bleaching of the kaolin as the sucrose concentration, relationship C:N:P, relationship water:substratum, temperature, besides the determination of the biological nature of the process. The rate of certain bleaching in each experiment was characterized, in function of a bleaching scale specifically elaborated for this work. Before and after the bioprocessing, the study material was submitted to the analyses by Atomic Absorption Spectrometry (AAS), determination of the specific surface and volume of pores (BET) and X-ray difractometry (XRD). The obtained results indicated that the ideal range of sucrose concentration was from 4,0% to 5,5% in relation to the substratum. The relationship C:N:P that promoted a better result in the process was equal for 250:1:0,2, reducing the time for beginning of the bleaching process. The relationship water:kaolin between 3,0:1 and 2,0:1 showed to be the ideal range for the development of the studied process. As the temperature, which it observed was a better acting when the same was maintained in 30oC and, to for 35oC the results were similar. Below 30oC and above 35oC the bleaching process is affected drastically. The confirmation of the biological nature of the process was also verified. The analyses of Atomic Absorption Spectrometry (AAS), showed a reduction of more than 40% in the grade of iron contained in the original material. The X-ray difractometry (XRD), showed that the biological bleaching improved the characteristics of the processed material... (Complete abstract, click electronic address below).
This work was carried out at the laboratory of geochemical of the Departmento de Recursos Naturais of FCA-UNESP LAGEADO, Botucatu(SP). It was used as basic material of study, the clay of the type kaulinite, obtained in the area of Botucatu(SP). Several experiments were driven with the objective of determining the ideal levels for the parameters that could influence in the bleaching of the kaolin as the sucrose concentration, relationship C:N:P, relationship water:substratum, temperature, besides the determination of the biological nature of the process. The rate of certain bleaching in each experiment was characterized, in function of a bleaching scale specifically elaborated for this work. Before and after the bioprocessing, the study material was submitted to the analyses by Atomic Absorption Spectrometry (AAS), determination of the specific surface and volume of pores (BET) and X-ray difractometry (XRD). The obtained results indicated that the ideal range of sucrose concentration was from 4,0% to 5,5% in relation to the substratum. The relationship C:N:P that promoted a better result in the process was equal for 250:1:0,2, reducing the time for beginning of the bleaching process. The relationship water:kaolin between 3,0:1 and 2,0:1 showed to be the ideal range for the development of the studied process. As the temperature, which it observed was a better acting when the same was maintained in 30oC and, to for 35oC the results were similar. Below 30oC and above 35oC the bleaching process is affected drastically. The confirmation of the biological nature of the process was also verified. The analyses of Atomic Absorption Spectrometry (AAS), showed a reduction of more than 40% in the grade of iron contained in the original material. The X-ray difractometry (XRD), showed that the biological bleaching improved the characteristics of the processed material... (Complete abstract, click electronic address below).
Descrição
Palavras-chave
Branqueamento, Oxidos de ferro, Caulim
Como citar
SILVA, Silas Macedo. Atividade microbiana nas transformações dos óxidos de ferro para o branqueamento de minerais de argila. 2002. v, 76 f. Tese (doutorado) - Universidade Estadual Paulista, Faculdade de Ciências Agronômicas, 2002.