Investigation of nitric acid dissolution of stibnite in the presence of tartaric acid

This study explores the nitric acid leaching of stibnite in the presence of tartaric acid, which acts as a complexing agent. The proposed approach is of considerable interest, as antimony is widely used across industries, from electronics to alloying applications. Thermodynamic analysis showed that nitric acid dissolution of stibnite inevitably leads to the formation of antimony oxides, which markedly reduces the extraction of the target metal into solution. To counteract these losses and enhance process efficiency, tartaric acid was introduced as an additive. The results demonstrated that tartaric acid promotes the formation of stable complexes with antimony ions, thereby retaining the metal in solution and minimizing the risk of oxide precipitation. Experimental design analysis revealed that the mass ratio of tartaric acid to antimony and the nitric acid concentration exert a stronger influence on leaching efficiency than temperature and leaching duration. Optimal conditions were established, achieving an antimony extraction of 87 %: temperature 35 °C, nitric acid concentration 5 mol/dm3 , leaching time 45 min, and a tartaric acid-to-antimony mass ratio of 4.5 : 1.0.