Optimization of Dissolution Parameters for GH4738 Scrap via Response Surface Methodology

This study aimed to optimize the electrochemical dissolution process of GH4738 scrap, a Ni-based superalloy, to achieve a high dissolution rate with minimal energy consumption. Using the Plackett-Burman design, we identified four key factors from a pool of eight candidates that significantly influence both the dissolution rate and energy consumption: current density, NiCl₂ concentration, electrolysis time, and H₂SO₄ concentration. The steepest ascent method was then applied to define a region that minimized energy consumption while maximizing the dissolution rate. Response surface methodology (RSM) was used to determine the central point for further analysis, providing valuable insights for optimizing the dissolution parameters. The study demonstrated that increasing the NiCl₂ concentration reduced the breakdown potential, and at an H₂SO₄ concentration of 1.5 mol/L, high dissolution efficiency was achieved with minimal energy consumption. The interactions among the parameters significantly affected the dissolution performance. Analysis of variance (ANOVA) confirmed the significant influence of these parameters on the dissolution behavior of Ni-based superalloys. This research contributes to the understanding of GH4738 scrap dissolution and provides a systematic approach for optimizing the process, which is crucial for efficient material recovery and laboratory sustainability.