Optimization of Nickel Precipitation and Leaching Process from Simulated Industrial Waste: A Study on pH, Contact Time, and Sulfuric Acid Concentration

The presence of nickel in industrial waste has emerged as a significant environmental concern, predominantly attributed to the plating industry. The significant objective of this study is to optimize the precipitation and leaching method to extract valuable nickel from the waste material. The high concentration of nickel found in the waste makes it a potentially valuable resource. To explore its potential extraction, the precipitation and leaching processes were optimized using a simulated Watts bath solution which is widely employed in the industry. This study focuses on examining the influence of pH, contact time, and sulfuric acid concentration on the extraction of nickel concentration during the precipitation and leaching processes. To develop a prediction model for the process, three models were taken into consideration: quadratic, linear, and 2F1. The quadratic model exhibited the greatest adjusted R2 value, suggesting a superior level of fit in comparison with the linear and 2F1 models. The predicted R2 value of 0.8169 exhibits a satisfactory level of concordance with the adjusted R2 value of 0.9737. The recommended optimal conditions proposed by response surface methodology (RSM) consisted of a pH value of 10.56, a contact time of 16.52 h, and a sulfuric acid concentration of 1.80 M in order to achieve a nickel concentration of 28,415 mg/L.