Bench-scale testing of the multi-gravity separator in combination with microcel. Final report

Abstract

It was the purpose of this investigation to test a new fine coal cleaning system, in which a coal is cleaned first by column flotation to remove primarily ash-forming minerals and then by an enhanced gravity separation technique to remove the pyrite remaining in the flotation product. Of the various column flotation technologies developed under the auspices of the US Department of Energy, the Microcel{sup TM} flotation column was chosen because it is being used commercially in the US coal industry, particularly by low-sulfur coal producers. Of the various enhanced gravity separation technologies used in minerals industry, Multi-Gravity Separator (MGS) was chosen because it shows promise for pyrite rejection from fine coal streams containing a wide range of particle sizes. The bench-scale tests were conducted using three different circuit configurations, i.e.; Microcel{sup TM} column alone; MGS alone; and Microcel{sup Tm} and MGS in series. In general, high ash-rejections were achieved using Microcel{sup TM} column and an MGS unit in series, both the ash and pyritic sulfur rejections exceeded what can be achieved using either the Microcel{sup TM} column or the MGS unit alone, demonstrating a synergistic effect.