PRE-CONCENTRATION ALTERNATIVES FOR THE REDUCTION OF THE CARBONATIC GANGUE OF A BRAZILIAN SILICATE ZINC ORE

摘要

Pre-concentration consists of the preliminary discarding of a fraction of the mineral processing plant feed which contains little or none of the mineral of interest, reducing the mass to be processed in downstream operations (e.g. milling, concentration, and dewatering) as well as the capital and operational costs. In this context, this study investigates the performance of density and sensor separation techniques in the removal of the carbonatic gangue of a Brazilian zinc ore in size fractions typical of crusher products, using sink and float tests with heavy liquid media, jig stratification, and laboratory-scale ore-sorting tests using an x-ray transmission (XRT) sensor. The best results were obtained in the sink and float in heavy liquid and indicate the possibility of discarding 30% of the feed mass of the plant, removing over 50% of the carbonate while losing only 2% of the zinc. The ore sorting tests also presented positive results, with an average metallurgical recovery of 93% in 73% of the mass. The results indicate a significant potential reduction of Capex and Opex using these pre-concentration methods.