Beneficiation of high-ash Indian coal fines by froth flotation using bio-degradable-oil as a collector

ABSTRACT

The present paper outlines the work done on beneficiation of low-rank-oxidized coal fines by flotation using a biodegradable oil (iluppai or Mahua) to reduce the ash content. Prior to flotation, characterization of the coal and the reagents were done by FTIR and SEM-EDS analysis to identify the functional groups. Batch tests were performed with biodegradable and conventional oil (Diesel) as collectors to compare the flotation performances with an Index known as ‘Separation Index’. The results of the tests conducted revealed that biodegradable Iluppai oil to be the better collector than conventional diesel oil. In the study, the effect of variables like reagent dosages and feed solid concentration was investigated for both the type of collectors. Further, the paper concludes that it is possible to reduce ash% of the low-rank-oxidized coal from a feed ash of 29.9% down up-to 16.60% using Iluppai oil with simultaneous enrichment in Gross Calorific value of coal from 5547.0 to 6861 kCal/kg. From the results obtained, an assessment of the kinetic behavior of the process is made based on the enrichment achieved in the Gross calorific value. The first-order rate equation parameters (Rx) and (k) evaluated for the GCV recovery established that the biodegradable oil as the promising collector.

KEYWORDS:

• Oxidized coal fines
• froth flotation
• biodegradable oil
• diesel oil
• combustible matter recovery