Kosaka Smelting and Refining Co., Ltd. installed tin recovery process in 2012 and produces around 550 tons of tin annually. Tin is contained in E-scraps. E-scraps are processed in a TSL furnace, and tin is recovered as dust with lead. The dust is processed in a lead electric furnace and tin is distributed to crude lead. Agitating the molten crude lead, tin is oxidized into the form of dross and separated from lead. Tin metal is produced from dross through both pyrometallurgical and hydrometallurgical sections. In the future, Kosaka plans to expand E-scraps processing capacity and increase tin production. To achieve this plan, it is necessary to improve the productivity of tin recovery process. Since conventional air oxidation process for tin took a long time, this oxidation process was a rate-determining step in the lead refining process. When tin input increased temporarily, it was necessary to reduce the amount of charge to the lead electric furnace. To solve this problem, oxidation process was reviewed. This improvement increased the separation speed and made it possible to maintain a high charge amount to the lead electric furnace. In the electrolysis process, dendrites and spongy electrodeposition caused short circuit and increased dross generated during dissolution. By changing the management of the electrolyte, the electrodeposition state became smooth, and dross generated decreased. In addition, we will report the high-purity tin in the electrolysis process.