Contaminants Recovery from Acid Mine Drainage

Abstract:

In some mines where sulfide minerals can occur in form of pyrite acid mine drainage (AMD) may occur, and it constitutes one of the main environmental impact. In order to prevent that AMD compromises aquifers layers and reaches mine surroundings, a treatment that consists in its neutralization with the use of a hydrated lime suspension is usually conducted. Contaminants that are soluble in AMD are precipitated, remaining in the solid phase. The work here presented aims recover uranium and rare earths found in one of these precipitates, which consists of calcium diuranate and metal hydroxides in a calcium sulfate matrix. This material contains approximately 0.25% of triuranium octoxide (U₃O₈) and 2.5% of rare earth oxides (TR₂O₃). The recovery of uranium and rare earths contained in the precipitate was performed through a hydrometallurgical process. The test resulted in a leaching with sulfuric acid presented solubilization of 96% for uranium and 90% for rare earths. A percentage yield of 99.7% and 99.9% was obtained in the steps of uranium extraction and re-extraction from the leachate, respectively.

• Periodical: Materials Science Forum (Volume 869)
• Pages: 1023-1027
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.869.1023
• Online since: August 2016
• Authors: Paulo Lima, Henrique Takuji Fukuma, Sandra Nakamatsu, Maria Gabriela Nogueira Campos, Maria Gabriela Nogueira Campos, Erika Coaglia Trindade Ramos, Neide Aparecida Mariano
• Keywords: Acid Mine Drainage, Hydrometallurgy, Rare Earths, Solvent Extraction, Uranium

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