Evaluation of phosphate fertilizers for ameliorating acid mine waste

Harris, David L., and Lottermoser, Bernd G. (2006) Evaluation of phosphate fertilizers for ameliorating acid mine waste. Applied Geochemistry, 21 (7). pp. 1216-1225.

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Abstract

The aim of the study was to determine whether the application of bulk industrial chemicals (potassium permanganate and water-soluble phosphate fertilizer) to partly oxidized, polyminerallic mine wastes can inhibit sulfide oxidation, and metal and metalloid mobility. The acid producing waste rocks were metal (PbZnCu) and metalloid (AsSb) rich and consisted of major quartz, dickite, illite, and sulfide minerals (e.g. galena, chalcopyrite, tetrahedrite, sphalerite, pyrite, arsenopyrite), as well as minor to trace amounts of pre- and post-mining oxidation products (e.g. hydrated Fe, Cu, Pb and alkali mineral salts). SEM-EDS observations of treated waste material showed that metal, metal-alkali and alkali phosphate coatings developed on all sulfides. The abundance of phosphate phases was dependant on the fertilizer type and the availability of metal and alkali cations in solution. In turn, the release of cations was dependent on the amount of sulfide oxidation induced by KMnO4 during the experiment and the dissolution of soluble sulfates. Manganese, Ca, Fe and Pb phosphates remained stable during H2O2 leaching, preventing acid generation and metal release. In contrast, the lack of complete phosphate coating on arsenopyrite allowed oxidation and leaching of As to proceed. The mobilized As did not form phosphate phases and consequently, As displayed the greatest release from the coated waste. Thus, the application of KMnO4 and the water-soluble phosphate fertilizer Trifos (Ca(H2PO4)2) to partly oxidized, polyminerallic mine wastes suppresses sulfide oxidation and is most effective in inhibiting Cu, Pb and Zn (Sb) release. However, the technique appears ineffective in suppressing oxidation of arsenopyrite and preventing As leaching.

Item ID: 1597
Item Type: Article (Research - C1)
ISSN: 1872-9134
Keywords: phosphate stabilization, mine wastes, lead, zinc, copper, arsenic, antimony, sulfides, phosphates, Australia
Date Deposited: 20 Aug 2007
FoR Codes: 04 EARTH SCIENCES > 0403 Geology > 040306 Mineralogy and Crystallography @ 50%
04 EARTH SCIENCES > 0402 Geochemistry > 040299 Geochemistry not elsewhere classified @ 50%
SEO Codes: 84 MINERAL RESOURCES (excl. Energy Resources) > 8498 Environmentally Sustainable Mineral Resource Activities > 849899 Environmentally Sustainable Mineral Resource Activities not elsewhere classified @ 51%
85 ENERGY > 8598 Environmentally Sustainable Energy Activities > 859899 Environmentally Sustainable Energy Activities not elsewhere classified @ 49%
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