Integrating flotation to improve the performance of an HMC circuit treating a low-rank fine coal

Abstract

One reason that heavy media cyclone (HMC) circuits suffer from the inadvertent loss of magnetite and fine coal is the presence of nonmagnetic material in the magnetic separator feed. In this study, flotation was applied to the undersize fractions of the HMC drain-and-rinse screens to minimize these problems. These fractions, which contain 17.9% nonmagnetic material, are currently sent to magnetic separators and the nonmagnetic portion from the separators contains 39.1% ash. Applying flotation resulted in a clean coal product with an ash content of 8.7% and a calorific value of 6,300 kcal/kg. The refuse from flotation, which will be sent to the magnetic separators, contains 7.7% nonmagnetics.