Investigation of leaching and leaching kinetics of malachite mineral by ammonium nitrate solutions

In this present work, leaching and leaching kinetics of malachite (CuCO3.Cu(OH)2) mineral in ammonium nitrate solutions have been investigated. In the experiments, the ammonium nitrate concentration, the particle size, the stirring speed, the solid to liquid ratio (K/S) and the reaction temperature have been chosen as variable parameters. As a result of peresent experiments, it was observed that the decrease of the particle size, the solid to liquid ratio, and the increase of the reaction temperature, the ammonium nitrate concentration and the stirring speed increased the dissolution rate.The reaction kinetics of malachite ore in ammonium nitrate solutions according to the heterogenous reaction models were examined. It was found that the reaction was obeying the shrinking core model and the dissolution rate was controlled by diffusion from ash layer. The calculated activation energy was 53.68 kJ/mol. The model for dissolution kinetics can be expressed as;t/t* = 1-3(1-x)(2/3) + 2(1-x)=1.127x10-4(CA)1.068 (D)- 0.929 (K/S)-0.850 (v)0.185exp(-6462.6/T ) t