Alkali−free Process for Enhancing the Flotation of Associated Silver in Yulong Lead−Zinc Ore with Modified Dithiophosphate−type Collector

Aiming at the low recovery of associated silver minerals during the flotation process of Yulong lead−zinc ore, a study on an alkali−free lead−silver flotation process with a novel collector was conducted. The research results indicated that, at a grinding fineness of −74 μm accounting for 65%, using sodium sulfite and zinc sulfate as depressants, and adopting the modified dithiophosphate−type collector CY−1, significantly enhanced the silver recovery in lead−silver concentrate under alkali−free conditions. Closed−circuit experiment of this process obtained the lead−silver concentrate with a lead grade of 52.05% and a silver grade of 4 866 g/t. The recovery rates for lead and silver were 91.76% and 84.43%, respectively. Compared to the high−alkali process using sodium diethyldithiocarbamate and ammonium dibutyl dithiophosphate as collectors, the lead and silver recovery rates increased by 2.5 and 6 percentage points, respectively. This process eliminates the depression of lime on silver minerals during the flotation process, contributing to the comprehensive recovery of rare precious metals associated with lead−zinc ore and enhancing the overall resource utilization efficiency.