Pre-concentration potential evaluation for a silicate zinc ore by density and sensor-based sorting methods

Abstract 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-based sorting separation methods in the removal of carbonate gangue of a zinc ore, in size fractions typical of crusher products, using sink and float tests with heavy liquids, jig stratification and laboratory scale ore sorting tests using an X-Ray Transmission (XRT) sensor. The best results were obtained through sink and float in heavy liquids, which indicated the possibility of discarding 30% of the feed mass, removing over 60% of the carbonates (CaO and MgO) and losing only 2% of the zinc. The ore sorting tests also presented positive results, with approximately 93% of metallurgical recovery in 70% of the mass for both size fractions tested. The jig stratification results were worse, since the zinc content discarded with this method was high. The results indicate significant reduction potential for Capex and Opex costs using pre-concentration strategy.

摘要
预选富集是指预先丢弃选矿厂给矿中含目标矿物极少或完全不含目标矿物的部分，从而缩减下游作业（如磨矿、选别与脱水）的处理矿量，同时降低基建投资与运营成本。在此研究背景下，本研究以破碎机产物的典型粒级为对象，采用重液浮沉试验、跳汰分层以及搭载X射线透射（XRT）传感器的实验室规模矿石分选试验，探究基于密度与传感器的分选方法脱除锌矿石中碳酸盐脉石的性能。
重液浮沉试验取得最优结果：该方法可丢弃30%的给矿矿量，脱除超过60%的碳酸盐（氧化钙CaO与氧化镁MgO），且仅损失2%的锌。矿石分选试验同样取得了积极效果，在两种被测粒级中，70%的矿量可实现约93%的金属回收率。而跳汰分层的试验效果欠佳，该方法的锌损失量较高。
研究结果表明，采用预选富集策略可显著降低资本支出（Capex）与运营支出（Opex）成本。