Tin Smelting using Carbonized Palm Kernel Shell as Reductant

Abstract

PT Timah Tbk has a vision to become a leading environmentally friendly mining company. To achieve this, efforts are being made to use biomass, specifically palm kernel shells, as a reductant in the smelting process, aiming to reduce carbon emissions associated with smelting. Palm kernel shells are selected due to their abundant availability in the Bangka Belitung Islands Province, the operational area of PT Timah Tbk. Before being utilized in the smelting process, palm kernel shells undergo carbonization at a temperature of 400°C for 15 minutes to increase the content of fixed carbon, which plays a crucial role in tin reduction. Carbonized palm kernel shells consist of 51.4% fixed carbon, 27% volatile matter, 14.54% ash, and 7.06% inherent moisture. The smelting process using carbonized palm kernel shells takes place in a Reverberatory Furnace and serves as the initial stage of the tin smelting process. In this stage, tin concentrate is smelted to produce crude tin and slag 1, with a slag 1 assay typically ranging from 15% to 20%. After three cycles of smelting, the average formation of crude tin is 83.31%, the Sn slag assay is 18.70%, and the smelting capacity reaches 50 tons per day. These results align with the standards set for stage 1 of tin smelting at PT Timah Tbk, which traditionally uses coal as a reductant. Therefore, smelting tin with carbonized palm kernel shell as a reductant is a viable and feasible option.