Substitution of magnetite in dense medium separation by Zinc-Lead waste

Abstract

Dense Medium (or Heavy Medium) Separation (DMS) is one of the most efficient and commonly used method of separation in different mining branches. Dense Medium for coal processing is based on the suspension of fine and dense material, usually magnetite or ferrosilicon, in water. Magnetite for that purpose is the most commonly used mineral in Polish mines, but has to be entirely imported from abroad. Ferrosilicon, recovered from Zinc-Lead waste could be an alternate to magnetite for use in DMS coal processing. In this study an attempt of recovering that material from “Miasteczko Śląskie” Zinc Plant wastes was made. By simple separation and comminution processes, large amount of magnetic fraction, which could be successfully used in dense medium as the substitution for the magnetite was obtained. Almost 70% of collected waste from lead refining process is proper for the use in the DMS process. Obtained fraction is relatively brittle and easy to grind, which should generate minor costs of production. Almost entire fraction is also highly reactive for magnetic field, which will be helpful in the recovery from dense medium solution, using existing magnetic separators in coal processing plants. Chemical analysis show that concentration of a few metals is significant, which may cause environmental obstacles. But that can also be solved, using simple method of recovery of metal ions from process water.