Application of the response surface methodology to optimize the characteristics of weathered discard coals using the W/O HIP emulsion technique

Abstract

ABSTRACT There is literature inadequacy for the application of high internal phase water-in-oil (HIP W/O) emulsion on agglomeration and flotation of weathered discards from coal discard dumps. In this study, two oxidized coal discards were beneficiated using W/O HIP emulsion technique. The performance of the W/O emulsion technique with an internal dispersed water phase of 95 vol% was compared with that of pure 100% kerosene. Response surface methodology was applied in the optimization of the two low-grade discard coals to generate mathematical regression equations to predict the response of the ash content and calorific value of clean coal products. The feed calorific value of 8.48 MJ/kg and 16.29 MJ/kg increased to 19.45 MJ/kg and 28.12 MJ/kg for discard coal 1 and 2, respectively. This was achieved with 5 kg/ton of emulsion binder, which is 0.25 kg/ton of organic dosage and at an agitation speed of 1800 rpm. A clean coal product with 19.05 MJ/kg and 27.20 MJ/kg was achieved under 5 kg/ton of pure 100% organic kerosene dosage. Statistical tools: Pred. R2 and Adj. R2 were established and confirmed the accuracy of the developed models. Overall, this study shows that the emulsion binder could upgrade weathered discard coal dumped for over three decades and achieved better quality product compared to kerosene.