Mixed-Type Flotation-and-Hydrometallurgical Process of Zinc Recovery from Manmade Mineral Reserves

The prospects for processing old tailings with zinc content of 0.7–0.8% are discussed. The flotation and hydrometallurgical methods of ore processing are most often studied separately, while their combinations are understudied. It is found that the size grade of the original material exceeds the optimized size for the efficient flotation of sulfide complex ore. It is proposed to combine re-grinding of tailings with activation of sphalerite using blue copperas. The mixed-type flotation-and-hydrometallurgical and hydrometallurgical-and-flotation processing flowsheets are compared. The end-to-end zinc recovery in the flotation-and-hydrometallurgical flowsheet is higher by 33.5% than in the hydrometallurgical-and-flotation flowsheet. Zinc recovery with sphalerite in flotation concentrate and oxidized zinc recovery in pregnant solution in leaching is the most complete. The flotation process stage can produce concentrates of high quality but zinc losses in scavenging flotation operations are high in this case. The need of an integrated approach to processing is substantiated: by-production of silver (at the content of ~ 29 g/t in the original material) improves the economic performance of the project. Processing of large quantities of manmade mineral reserves increases return on investment in the beneficiation project.