Recuperação hidrometalúrgica de metais da drenagem ácida de minas por precipitação seletiva

AUTOR(ES)
FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

2010

RESUMO

Acid mine drainage (AMD) is an important water pollution problem in coal production. The active treatment of AMD involves the addition of alkaline reagents to increase the pH and precipitate the dissolved metals as hydroxides. Although active treatment can provide effective remediation, it has the disadvantages of high operational costs and problems related to the disposal of the bulky sludge that is produced. One potential way to extend the use of natural resources is to recover potentially valuable products, such as some of the precipitated metals from the AMD. The aim of this work was to study the process of selective precipitation for the recovery or iron and/or iron + aluminum for the production of chemical coagulants and iron pigments. The AMD was collected from a drainage channel near a tailing deposit in Santa Catarina State (Brazil) and characterized. Iron was recovered from the AMD by a selective precipitation at pH 3.6 ± 0.1 and iron + aluminum at pH 5.1 ± 0.1. The precipitate obtained at pH 3.6 ± 0.1 was used for the production of the coagulant ferric sulfate and the pigments yellow (goethite), red (hematite) and black (magnetite). The precipitate obtained at pH 5.1 ± 0.1 was used for the production of an aluminum-iron sulfate coagulant. Both coagulants was characterized in terms of their chemical composition and showed to be efficient for water treatment. The pigments were characterized in terms of their particle size, thermal behavior, chemical composition and colorimetric properties. The pigments produces were successfully applied for the production of paints and colored concretes. It was possible to conclude that the process of selective precipitation reduced in about 80% the volume of sludge in AMD treatment plants, allowing producing valuable materials. The technology is feasible and can be economically profitable. The process reduces the material loss, minimizes environmental impacts, and should be considered as an economical activity by the Brazilian coal industry.

ASSUNTO(S)

drenagem ácida de minas hidrometalurgia carvão

ACESSO AO ARTIGO

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