Efficient Leaching Process of Valuable Elements from Gibbsite Ore Materials in Talet Seleim, Southwestern, Sinai, Egypt Using Green and Ecofriendly Lixiviant Agent: Optimization, Kinetic and Thermodynamic Study

Here, valuable elements in Talet Seleim, Southwestern Sinai, Egypt, were leached using methanesulfonic acid (MSA) as an environmentally friendly lixiviant agent. The effects of methanesulfonic acid (MSA) concentration, time of leaching reaction, temperature, liquid/solid ratio (L/S) and stirring speed on dissolution of valuable elements in MSA were studied. The optimized conditions for dissolution of various metals were: methanesulfonic acid concentration; 150g/L, dissolution time; 300 min, temperature; 363K, liquid to solid ratio; 4 ml/g and stirring speed; 400 rpm. The dissolution efficiency of Zn, Cu, Ni and Pb are 81.8%, 79.47%, 76.6%, and 70.7%, respectively under the optimal conditions. Different mathematical kinetic models for the dissolution process in MSA were studied since it is very important for economic metal dissolution. The experimental data were best fitted by pseudo-second-order homogeneous reaction model for zinc (Zn), copper (Cu) and nickel (Ni), whilst lead (Pb) was best fitted by the diffusion through the product or ash layer. The activation energies of the dissolution processes of different metals were evaluated. Overall, the MSA leaching system provides an efficient, clean and green method for dissolution of valuable metals. It can be a promising alternative to inorganic acids.