Leaching of chromium from coal ash using citric acid, oxalic acid and gluconic acid by batch leaching procedure

This study aims to leach chromium from coal fly ash using citric acid, oxalic acid and gluconic acid. Fly ash obtained from coal ash pond comprises of 28 ppm chromium. After the batch leaching procedure, the results show that 27.66% of chromium was leached using 0.3 M citric acid with the contact time of 8 hours. Also, the order of the ability of the organic acid to leached chromium are as follows citric acid > gluconic acid > oxalic acid. Moreover, mixture of 3 organic acids were used with 0.0317 M citric acid, 0.0266 M oxalic acid and 0.06265 M gluconic acid with varying contact time. Only 8.62% of chromium was leached after 24 hours using mixed organic acid.