Size by size performance analysis of a Leebar dense media bath

ABSTRACT

Size-by-size performance analysis has been carried out for a 300 tph Leebar dense media bath cleaning met coal. Feed size distribution and feed density distribution both have a considerable effect on the cleaning performance. The results show on a composite basis that in spite of a wide feed size range of practically −200 + 0 mm, the Leebar bath with organic efficiency of 98% and Ecart probable error of 0.09 fares reasonably well and ensures 78.6% yield at the target ash of ≤18%. Performance is distinctly superior for the size fractions coarser than 51 mm, constituting around 56% of the feed mass, the size being kind of breakaway size in this specific case. The results further show a monotonous dependency of organic efficiency on cut density with R² value of 0.953 and indicates a high-efficiency separation at lower cut densities (CDs). With R² value of 0.923, organic efficiency continually improves with the increase in feed particle size. For +70 mm size fractions at CDs of ≤1.52, organic efficiency is close to 100. Major misplacement is observed for reject in clean coal. Misplacement does not show any size-specific trend, though maximum misplacement is recorded for the finest size fractions. A generalized trend appears to indicate that misplacement increases with the increase in near-gravity material, though no relation can be approximated.

KEYWORDS:

• Leebar bath
• cut density
• misplacement
• Ecart probable
• imperfection
• organic efficiency