Abstract
Structural Equation Modelling (SEM) is now widely used to explore the joint performance of factors affecting a process and to quantify the effect of each factor in the presence of the others. In this research work, SEM analysis was conducted to develop Structural Equation Models that well predict the leaching behaviour of Cu, Co, Ni and Fe in HCl aqueous solution of an oxidised copper-cobalt ore.
A comprehensive set of experimental batch leaching tests was executed to study the effect of operating variables (pH, time, temperature and stirring speed) on the relative leaching yields of Cu, Co, Ni and Fe during the leaching of an oxidised copper-cobalt ore sample in an HCl aqueous solution. The gangue acid consumption was also measured to aid in understanding the behaviour of the gangue. The experimental results obtained were statistically analysed and modelled using the SEM procedure.
The Structural Equation Models obtained showed that Cu and Co leaching yields had a strong positive dependence on both the leaching time and leaching temperature, while Fe leaching yield had a moderate dependence on the leaching temperature, stirring speed and the covariate Z (Z = stirring_speed*pH). On the contrary, Ni leaching yield had a strong negative dependence on both the stirring speed and the covariate Z.
The Structural Equation Models agreed fairly with the experimental results obtained upon leaching. This is a clear indication that the models can be used to predict the leaching yields given a set of leaching parameters.