Zinc recovery from Wulagen sulphide flotation plant tail, part II: pilot tests using cyclonic static microbubble flotation column

Abstract

ABSTRACT Pilot scale flotation tests (maximum capacity 1 mt h−1) on refloating smithsonite from sulphide flotation tail using cyclonic static microbubble flotation column (FCSMC) were carried out at the Wulagen Mine site. FCSMC is easy to install and operate, ideal for pilot tests. Condition (optimisation) tests were carried out first to verify the reagent scheme obtained in previous bench scale tests in lab. Similar conclusions with lab bench scale tests can be obtained: (1) Normal alkyl ether amine OPA 1214 is a suitable collector. (2) Sodium carbonate, sodium silicate and sodium sulphide is suitable modifier combination. (3) Desliming promoted smithsonite flotation. But dosages of ether amine and sodium sulphide in pilot scale flotation tests were lower. Continuing tests was carried out after rougher conditions were optimised. First test had one rougher, one scavenger and two cleanings. A cleaning concentrate was obtained with a Zn grade higher than 20%, but recovery was low (<20%). To increase the Zn recovery, process modifications were made including converting the scavenger stage into the second rougher stage, and combining two rougher concentrates as cleaning feed. A concentrate with an average grade higher than 30% and recovery higher than 50% was obtained. Based on particle size analysis on products of continuing tests, FCSMC showed stronger collecting power and selectivity for fine smithsonite particles, which is suitable for treating this feed.