Upgrading 1st tin slag’s tantalum and niobium pentoxide by sodium hydroxide quenching and nitric acid leaching

Tin smelting produces byproducts in the form of slag. In tin slag, there are two valuable oxides, namely tantalum and niobium pentoxide (TNP). This research explores the effect of HNO3 leaching on increasing 1st tin slag (1TS) TNP. To deal with the investigation, roasting at 900°C, 0.5 M NaOH quenching, and an X-ray fluorescence (XRF) analysis were carried out. The XRF observation was also conducted to characterize Al2O3, SiO2, Fe2O3, and SnO2 in the filtrates of HNO3−leached 1TS. The result shows that the Ta2O5 and Nb2O5 contents rise to 0.35% through the 8 M HNO3 leaching and to 0.67% through the 6M HNO3 leaching. Another result is that the 100 mesh of 0.10% Ta2O5 and 0.20% Nb2O5 has the least adherent compounds, 62.70%. This study has proven that, first, leaching 0.5 M NaOH in 1TS effectively dissolves TNP and, secondly, the HNO3 leaching in specific concentrations maximally upgrades the TNP contents.