Evaluation of the potential of recovering various valuable elements from a vanadiferous titanomagnetite tailing based on chemical and process mineralogical characterization.

In order to evaluate the potential of recovering various valuable elements from vanadiferous titanomagnetite tailing (VTMT), the chemical and process mineralogical characterization of VTMT were investigated in this study by various analytical techniques such as XRF, XRD, optical microscopy, SEM, EDS, and AMICS. It was found that VTMT is a coarser powder in general; about 50% of the particle size is greater than 54.30 µm. The total iron content of the VTMT was 22.40 wt.%, and its TiO2 grade is 14.45 wt.%, even higher than those found in natural ilmenite ores. The majority of iron and titanium were located in ilmenite and hematite; 62.84% of hematite and 90.27% of ilmenite were present in monomeric form. However, there is still a portion of ilmenite and hematite embedded in gangue such as anorthite, diopside, and serpentite. For the recovery of valuable fractions such as Fe and TiO2 from VTMT, a treatment process including ball milling-high-intensity magnetic separation-one roughing and three refining flotation was proposed. Finally, a concentrate with TiO2 grade of 47.31% and total Fe (TFe) grade of 35.44% was produced; TiO2 and TFe had recovery rates of 57.71% and 28.23%, respectively. The recovered product is adequate as a raw material for the production of rutile. This study provides a reference and a new research direction for the recycling and comprehensive utilization of VTMT.

A novel method for dearsenization from arsenic-bearing waste slag by selective chlorination and low-temperature volatilization.

Because of the widespread presence of arsenic in various smelting waste slags, it not only hinders the recycling and utilization of waste slag, but also causes serious pollution to the ecological environment. In this study, As2O3, the main form of arsenic in non-ferrous metal smelting slag, was used as the research object, and FeCl3 was used as the chlorination agent. As2O3 was selectively chlorinated to low-boiling-point AsCl3 gas which was easy to be volatilized and removed by chlorination roasting. According to the thermodynamic calculation results, the feasibility of FeCl3 as the chlorination agent for selective chlorination and low-temperature volatilization of dearsenization was analyzed. The TG-DTA diagram was analyzed by thermogravimetric experiment, and the mass change, endothermic and exothermic behaviors of the As2O3-FeCl3 system during the linear heating process were studied. The effects of roasting temperature, roasting time, and molar ratio of reactants on the chlorination-volatilization of the As2O3-FeCl3 system were investigated. The optimal chlorination roasting conditions were determined with a roasting temperature of 290-300 ℃, a roasting time of 50 min, and a reactant FeCl3/As2O3 molar ratio of 4:1. The results of this study provided a novel idea for the removal of arsenic from smelting slag and dust, but the mechanism and process conditions of chlorination still need to be further studied and optimized.