Ferric Sulphate Produced From Pyrite Concentrate of Coal Tailings to Water and Wastewater Treatment

摘要

Coal mining produces large amounts of wastes rich in pyrite (FeS_2), which in contact with water, oxygen and bacteria generate acid mine drainage (AMD). Due to its composition and the major environmental problem caused by the AMD, the objective of this work was the production of the coagulant ferric sulfate (Fe_2(SO_4)_3) from the oxidation of pyrite contained in the tailings of coal. The methodology was based primarily on the characterization of the pyrite concentrate, obtained by reprocessing the waste, both collected in the coal mine of Figueira-PR. Later, leaching tests were conducted for four weeks in two columns. After the four week, the solutions were filtered and evaporated to reach levels close to 12% of iron in the solution. The coagulant chemical quality was evaluated in terms of concentration of Fe, other metals and sulphate. The coagulant produced in previous stages, was tested for the treatment of water to human consume, proving its effectiveness, given the parameters required by water legislation. Thus, the production of ferric sulfate by pyrite leaching was shown to be effective and can add value to a residue that still causes a major environmental liability.