Work

The effect of iron complexes−nitrilotriacetate in the bio−oxidation of sulphide minerals: Toxic metal(loid)s release and surface microstructure

Year: 2024

Type: article

Abstract: Mineral exploitation and processing lead to the production of a large amount of stibnite−containing waste, which are the main sources of toxic metal(loid)s pollution in soil and water ecosystems. Bio−oxidation is an important driving force for pollution formation. However, the release of Sb in the association of stibnite and arsenopyrite in the presence of NTA is still unclear. In this study, stibnite, stibnite−arsenopyrite and stibnite−arsenopyrite−NTA were designed to study the release characteristics of Sb. And the microstructure of elements in the reaction microinterface was analyzed by high-precision spectral characterization such as SRXRD and XPS. The results showed that the arsenopyrite increased the release of Sb in stibnite to 1600 mg/kg. The addition of NTA further enhanced the release of Sb and As, increasing 17292 and 43130 mg/kg. However, the concentration of Fe decreased but progressively increased due to the NTA added. Meanwhile, the existence of NTA decreased leachate pH from 2.25 to 1.45 and increased Eh from 273 mV to 323 mV. The presence of NTA reduced the FeAsS in the microinterface of minerals to 30.6%. Meanwhile, Fe2(SO4)3 and FeAsO4·2H2O decreased to 3.8% and 0.5%, Sb2O5 and As(III)−O increased to 22.4% and 21.9%. Indicating that the complexation of NTA with Fe(III) hindered the formation of passivates such as jarosite and scorodite and then promoted the bio−oxidation of arsenopyrite and stibnite. The new insight of stibnite bio−oxidation contributed to the understanding of sulfide oxidation mechanism and helped to put forward the control measures of pollution source in mining area.

Source: Journal of Hazardous Materials Advances

DOI: 10.1016/j.hazadv.2024.100557