Abstract: To address the challenges associated with lime application in the high alkali sulfur suppression lead flotation process for high-sulfur,high-carbon,and finely disseminated lead-zinc ores—such as pipeline scaling,low precious metal recov ery,and high wastewater treatment costs—this study focuses on a high-sulfur,high-carbon lead-zinc ore from Inner Mongolia. Based on process mineralogy research,a highly efficient depressant XKY-02 for pyrrhotite and a highly selective collector XK 201 for galena were developed for low-alkalinity conditions.Laboratory-scale closed-circuit tests were conducted using a "lead preferential flotation" process consisting of one stage of roughing,two stages of scavenging,and four stages of cleaning after re grinding of the rough concentrate.Under the optimal low-alkalinity reagent regime,a lead concentrate with a lead grade of 56.44%,silver grade of 260.55 g/t,lead recovery of 76.58%,and silver recovery of 45.29% was obtained.Compared with the conventional high-alkalinity reagent regime,the lead recovery increased by 5.39 percentage points and the silver recovery in creased by 7.61 percentage points.The low-alkalinity process significantly improved the pulp environment,notably enhanced the zinc concentrate index,and effectively reduced the consumption of lime and lead collector,demonstrating significant eco nomic and environmental benefits.This low-alkalinity process provides a new technical approach for the efficient utilization of refractory high-sulfur,high-carbon lead-zinc ores.

Key words: low-alkalinity process,galena,pyrrhotite,collector,depressant