US Patent Number
The present method induces an oxidation-proof ferric silicate coating on iron sulfide such as pyrite and marcasite. The method includes the steps of placing the pyrite to be treated in a reaction vessel and leaching the pyrite with a coating composition including water, an oxidizing agent and a silicate coating agent. Examples of oxidizing agents include hydrogen peroxide, sodium hypochlorite, potassium hypochlorite and mixtures thereof. The silicate coating agent may be sodium metasilicate. In order to ensure the formation of the stable coating, the leaching is performed at a pH of 4-6 and more preferably 5. Additionally, the oxidizing agent is maintained at a concentration of substantially 0.6% by weight of the coating composition while the concentration of the silicate coating agent is maintained at at least substantially 1.8×10-3 M/l.
University of Kentucky Research Foundation, Lexington, Ky.
Evangelou, V. P., "Oxidation Proof Silicate Surface Coating On Iron Sulfides" (1996). Plant and Soil Sciences Faculty Patents. 25.