Extracting Copper by Lactic Acid from Copper Oxide Ore and Dissolution Kinetics

In this study, an organic reagent was used as a leaching reagent for copper extraction from copper oxide ore. The effect of several factors, including leaching time, temperature, particle size, reagent concentration, and stirring speed, on leaching of the copper oxide ore as well as the leaching kinetics were determined. The copper leaching rate increased with increasing reagent concentration and reaction temperature, and decreasing particle size. The leaching process was described by an interfacial mass transfer-solid-film diffusion kinetic model; this indicates that the reaction occurs on the particle surface and throughout the entire diffusion region, including pores and cracks. The empirical equation for the dissolution process was established to be 1/3ln(1-x)+[(1-x)(-1/3)-1]=[1.94C(1.927)P(1.322) exp(-3507.34/T)]t. The apparent activation energy was calculated to be 29.16 kJ/mol using this equation. Lactic acid can be employed as an organic leaching reagent to obtain a copper solution suitable for subsequent electrowinning. The data obtained in this study provides useful information for the leaching of other carbonate minerals of metals such as copper, zinc, and cobalt in organic acid systems.