Enrichment of Tantalum and Niobium Contents in Bangka Tin Slag by NaOH and H3PO4Leaching

Abstract

This study explores how 0.23% tantalum and 0.47% niobium in tin slag from the Bangka-Belitung archipelago, Indonesia, are upgraded. To enrich the contents of both metals, this research involves 8M NaOH leaching followed by 0.5M, 1M, and 1.5M phosphoric acid. First, tin slag was roasted at 900°C for 2 hours. Then, the sample was NaOH-leached while H3PO4 was exploited to leach its residues. Next, each of the residues from the leaching processes was characterized by XRF while the filtrates characterization used AAS and ICP-OES. On the one hand, NaOH leaching has proven to decrease the contents of iron, calcium, titanium, and aluminum. On the other hand, 0.5 M H3PO4 leaching optimizes tantalum contents up to 0.85% while 1.0 M H3PO4 leaching maximizes niobium contents up to 1.45%.