Use of coal ash to restore acid mine drainage in the Moatize mine tete province, Mozambique

Abstract

The purpose of this research is to assess the potential of using coal ash for restoring Acid Mine Drainage. For this purpose, we decided to determine the physical-chemical composition of the coal waste, coal ash and effluent, where physical and chemical parameters were assessed. Mineralogical characterization of tailings was carried out, where quartz, kaolinite, siderite, palygorskite, muscovite and dolomite were verified. Geochemical characterization of coal ash was also done, where found Si, Al, Fe, K, Ca, Ti as the main elements and presence of Cu, Cr, Zn, Rb, Ir, Mn, As, Y, Pb, Nb, Th as trace elements, being defined by the X-Ray Diffraction and X-Ray Fluorescence method. The dynamic and the static of Fizz test methods were used, which showed the maximum time of absorption for H+ ions from the activation of ashes in the effluent. Satisfactory results were obtained after calcination, since the main acid-generating elements contained in the fine residues were converted to trace elements. The pH of the ashes was found to be neutral. It is concluded that coal ashes from fine coal tailings have the power to restore the Acid Mine Drainage.

Keywords

• acid mine drainage
• coal ash
• fine coal refuse
• remediation
• static and dynamic methods