Any processing plant dealing with sulphide minerals wants to control the amount of pyrite in their final concentrate. Depression of pyrite is complicated because the surface chemistry of pyrite is similar to that of valuable base metal sulphides. Additionally, galvanic interactions between pyrite and other sulphide minerals, combined with potential activation by ions present in the process water further complicates maintaining control over the amount pyrite reporting to the flotation concentrate.
At the Endeavor Mine in Cobar, NSW, production volumes suggest that the amount of pyrite in the final concentrate increases with the silver content in the ore. While there are several ways to deal with pyrite in concentrates, reduced production volumes of concentrates leave traditional ore blending techniques unavailable to the mine. Evaluation of different depressants revealed that Pionera F-250 adequately depressed pyrite demonstrated in both laboratory tests and in plant trials. F-250 was selected for use in the process as it efficiently reduced pyrite in the final concentrate and improved the grade of lead, silver and zinc concentrates produced.