Continuous heavy medium recovery by high gradient magnetic separation (HGMS)

Fine magnetite in water, used as a heavy medium for cleaning fine coal in cyclones is recovered for recycling by magnetic separation. HGMS has been introduced to this application of magnetic separators to improve magnetite recovery, increase material throughput rates and reduce plant space and flow sheet complexity. A continuous separator would be required when the feed slurry is dense and when matrix loading occurs quickly. Following laboratory batch separations, a test program was conducted on a 1.85 m diameter carousel continuous separator. The results were in close correspondence to the earlier batch work demonstrating that high magnetite recoveries are possible at high flow rates along with minimal coal retention in the magnetics.