Application of MLR Method and Pearson Correlation on Nickel Extraction from Laterite Using Nitric Acid

Indonesia is a country rich in laterite mining especially in Celebes island and northern Moluccas. Laterite is a mineral rich with precious nickel. Nitric acid leaching has been used for nickel extraction from laterite under the influence of nitric acid concentration (2.0 M, 4.0 M, and 6.0 M) and leaching temperature (65oC, 70oC, and 75oC) during 60 min. at 300 rpm. The preliminary study aims to apply multiple linear regression (MLR) method to examine the dominant effect between acid concentration and leaching temperature on nickel extraction, and also Pearson correlation to study significant correlation between the variables involved (acid concentration, leaching temperature, and nickel concentration). The method and results is related to acid leaching at varied temperature set up as predictors and nickel concentration as dependent variable in the MLR equation using the enter method. The MLR method showed that acid concentration gave significant effect on nickel concentration, however, the leaching temperature showed no significant effect on nickel extraction at t ≤ 0.05. The Pearson correlation showed acid concentration correlated significantly with nickel concentration. The Kolmogrov-Smirnov (K-S) test showed normality for distribution of nickel concentration. The acid leaching method is potential for nickel extraction from laterite using extensive range of acid concentrations and leaching temperatures to improve nickel extraction.