| The dissolution of arsenic associated with gold bearing ores such as arsenopyrite, realgar and opigment not only reduces gold recovery, it causes serious environmental problems. Several methods of arsenic removal and stabilization from industrial waste have been investigated. These include membrane separation, precipitation, ion exchange, adsorbing colloid flotation and carbon or other sorption technologies. Current existing methods of arsenic removal and stabilization from mining waste solutions involve precipitation, co-precipitation and adsorption with ferric sulfate, ferric chloride, lime, and alum. These methods remove arsenic primarily in the form of oxyanions of arsenic. The removal of arsenic by ferric salts and lime is not very effective due to the decomposition of both ferric and calcium arsenate in alkaline medium.; In this investigation, new methods of removing and stabilizing arsenic species using lanthanum chloride or combination of lanthanum chloride and ferric sulfate have been developed. The processes were tested in synthetic solutions, mine pit solutions, cyanide leach liquors and tailings slurries from the gold extraction process.; The nature of precipitation of oxyanions of arsenic with lanthanum chloride and ferric sulfate was characterized by zeta potential measurements. (Abstract shortened by UMI.)... |
