Analysis of the Effect of Increasing Sn²⁺ Content in the Electrolyte Solution from Leaching on the Recovery of the Electrorefining Process at PT. Timah Tbk

Indonesia

Abstract

Iron tin in this study is one of the by-products from the flame oven. This iron tin undergoes testing, yielding Sn content of 40.85% and Fe content of 31.32%. Tin Crystal is a product of pyrorefining, a process where tin is separated from various impurities such as As, Ni, Pb, Fe, among others. The study involves leaching process using 37% HCl solvent with varied volumes. From the leaching process, SnCl2 is obtained containing Sn2+. This solution undergoes titration to determine the Sn content. Subsequently, SnCl2 solution is added to an initial electrolyte solution containing 22 g/l to increase Sn2+ concentration. Electrorefining experiments were conducted using electrolyte solutions: PT Timah Tbk electrolyte, electrolyte with leaching solution 1, electrolyte with leaching solutions 1 and 2, and electrolyte with Tin Crystal leaching solution. Conditions included fixed parameters: voltage at 0.24V, experiment duration of 8 hours with hourly checks. Electrorefining process mirrored PT Timah Tbk's refining process, optimizing with 0.24V voltage for best results. Research findings showed leaching process produces SnCl2 solutions containing 80 to 130 g/l for iron tin (FeSn) samples and 150 g/l for Tin Crystal samples. Electrorefining yielded products of varying weights depending on Sn2+ concentration in the electrolyte. Quality differences were significant, suggesting the need for optimization towards superior products.