GB1249573A - Purification of acid mine water - Google Patents

Abstract

1,249,573. Purifying acid mine water. BLACK, SIVALLS & BRYSON Inc. 8 July, 1969 [17 July, 1968], No. 34464/69. Heading CIA. [Also in Division C7] A process for removing the sulphur content from sulphate-containing acid mine water, comprises neutralizing the water with a limecontaining slag, thereby precipitating the sulphate ion-containing solids, recovering and drying said solids, reducing the sulphate ion in the dried solids, to sulphide ion, oxidizing the sulphide ion to sulphur wherein the reduction is achieved by introducing the dried solids into a bath containing molten iron and carbon. The carbon in the bath may be introduced in the form of carbonaceous fuel which may optionally contain sulphur or pyrites which are converted to sulphides and molten iron, respectively. The heat for the process may be supplied by burning carbon monoxide produced in the reduction, to carbon dioxide. The precipitated sulphate ioncontaining solids are in the preferred embodiment, recovered from the mine water by distilling off the water. The oxide containing slag remaining after the oxidation of the sulphides to sulphur (oxygen originates from the reduction of sulphates to sulphides) may be used to neutralize the acid mine water and the resulting slag, with or without sulphate containing solids otherwise removed from the mine water, is introduced into the bath of molten iron. The sulphides may be converted to sulphur by contact with water to generate hydrogen sulphide, oxidation of part of the H 2 S to SO 2 and reaction of the remainder of the H 2 S with the SO 2 to produce sulphur. The process carried out in the bath of molten iron is preferably similar to that described in Specification 1,225,206.