RECOVERY OF COAL SLIME BY USING THE KNELSON CONCENTRATOR

Abstract

The coal slimes are formed during the gravity processes applied at the coal preparation plant (CoalWashery). After the washing process of coal, large amounts of fine coals with a high calorific value isbeing discharged to the abandoned open cast spaces causing economic losses and significantenvironmental problems. A re-processing of these coal slimes by using the newcomer separationdevices, such as Knelson concentrator, is a necessity due to the filling up of ponds, requirements ofnew legislation, and so on. In this study, the recovery of fine coal slimes of Tuncbilek Washery inKutahya-Turkey was carried out by using the Knelson Concentrator (KC). Besides, the effect ofparticles sizes on the recoverability of fine coals was also investigated to reach optimum recovery.According to the particle size analysis made for this purpose, the maximum particle size of thesamples was found as 4 mm while the ratio of material below 0.038 mm was found as 69.66%. Fromthe chemical analysis made (ash, calorific value), it was also found that the ash content and the uppercalorific value of the waste material 68% and 1603 kcal/kg, respectively. After the coal processingstudies carried out using the KC for two different particle size groups, it was realized that the recoveryrate was highly reduced at carbon content which is the indicator of the valuable substance while it wasslightly decreased at lower particle sizes. When all the coal processing results were considered, itcould be concluded that clean coal with 70% carbon content and an upper calorific of 4807,9 kcal/kgcould be obtained through a combustible recovery of 57.4%.