Removal of chromium from Enugu coal using HCl as leaching agent

Abstract

This study investigated the removal of chromium from Enugu Coal with HCL as the leaching agent under different conditions such as Leaching Time, particle size, acid concentration, and volume of leaching agent. The filtrate from each treatment was analyzed with Atomic Absorption X-ray Spectrometer (AAS) to determine the amount of Chromium leached. Similarly, the residual coal from each treated sample was also analyzed together with virgin coal using Scanning Electron Microscopy (SEM). Micrograph of virgin coal revealed the features of lithhophiles like aluminum and silicates. The absence of these features on the residual coal confirmed the removal of inorganic elements in residual samples. A quadratic model was predicted and optimized which resulted to Particle size of 50μm, reaction time of 35 hours, HCL concentration of 2mol/dm³ and Leaching agent of volume of 100mls. Optimum conditions were validated at model desirability of 1. Experimental value of 91.19% with error of 0.840% was removed.

Keywords: Coal, Optimization, Leaching, Chromium