The Washability of Lignites for Clay Removal

Abstract

In the washability research of the Seyitomer Lignites (Kutahya-Turkey), with lower calorific value (1,863 kcal/kg) and high ash content (51.91%), by heavy medium separation, it was found out that middling clay in the coal had an effect to change the medium density. To prevent this problem, a trommel sieve with 18 and 5 mm aperture diameter was designed, and the clay in the coal was tried to be removed using it before the coal was released to heavy medium. Following that, the obtained coal in −100 + 18 mm and −18 + 5 mm fractions was subjected to sink and float test having 1.4 gcm⁻³ and 1.7 gcm⁻³ medium densities (−5 mm fraction will be evaluated in a separate work). Depending on the raw coal, with the floating of −100 + 18 mm and −18 + 5 mm size fraction in 1.4 gcm⁻³ medium density, clean coal with 60.10% combustible matter recovery, 19.12% ash, and 3,150 kcal/kg was obtained. Also floating of the samples sinking in 1.4 gcm⁻³ in the medium density (1.7 gcm⁻³), middling with 18.70% combustible matter recovery, 41.93% ash, 2,150 kcal/kg, and tailing having 78.31% ash were obtained.

Keywords:

• heavy medium separation
• tommel sieve
• washability

Notes

^a The legislation on the protection of air quality by Ministry of the Environment and Forestry, 2004 (Committee Study Report, 2003).