Recovery of nickel from lateritic nickel ore using Aspergillus niger and optimization of parameters

The present study deals with the extraction of nickel from lateritic nickel ore of Sukinda mines, Orissa, through microbial leaching using Aspergillus niger. The presence of significant metals in oxidic nickel ores, are potential sources of nickel for the future. Thus, experiments were carried out with ore to optimize the conditions for maximum nickel recovery. Experiments designed as per central composite design technique, were carried out for fitting an empirical reduced second order model. The factors studied were sucrose concentration, pulp density, temperature and duration. In addition to main effects of four factors, sucrose concentration, pulp density and duration had quadratic effect on the percentage extraction and there were interactions between different factors also. There was also significant interaction between temperature and duration as well as sucrose and pulp density. The F-value for the model shows that model is significant at less than a 0.01% level (i.e. at 99.99% confidence level). The predicted maximum nickel extraction was 31.34% with a pulp density of 8.75%, sucrose concentration of 10.04 g/l, temperature 33.8 °C and duration of 37.5 days.