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Recovery of nickel and iron from low–grade laterite ore and red mud using co–reduction roasting: Industrial-scale test

Guo Xiaoshuang, Xu Chengyan, Wang Yingshuo, Li Xiaohui, Sun Tichang

Physicochemical Problems of Mineral Processing

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2021

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Vol. 57, iss. 3

61--72

EN

In this study, the effects of red mud (RM) dosage during the co-reduction roasting of lowgrade laterite ore and RM were investigated. The expanded test was conducted under the following optimized conditions: RM-1 dosage of 15 wt%, anthracite dosage of 13 wt%, a roasting temperature of 1300oC, and roasting time of 3 h. Ferronickel powder was obtained with a nickel grade of 1.95 wt%, iron grade of 83.25 wt%, and nickel and total iron recoveries of 94.71 wt% and 95.98 wt%, respectively. The addition of RM improved the recovery of nickel and total iron in ferronickel powder. The reason was because of the increased intensity of the diffraction peaks of kamacite and iron, and the ferronickel particles grown due to the liquid phase were easier to achieve at a lower melting point. The industrialscale test results showed that ferronickel powder was obtained with average nickel and total iron grades of 1.76 wt% and 86.46 wt%, respectively, which indicated the successful industrial-scale test of co–reduction roasting. Thermodynamic analysis theoretically illustrated the feasibility of the co–reduction of low-grade laterite ore and RM. Increased roasting temperature promoted the reduction of iron oxide and nickel oxide.

2

Effect of direct reduction time of vanadium titanomagnetite concentrate on the preparation and photocatalytic performance of calcium titanate

Li Xiaohui, Kou Jue, Sun Tichang, Wu Shichao, Tian Yuechao

Physicochemical Problems of Mineral Processing

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2021

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Vol. 57, iss. 1

75--86

EN

Effects of direct reduction time of vanadium titanomagnetite concentrate (VTCE) on the preparation and photocatalytic performance of calcium titanate were investigated in this study. It was found that extending the reduction time could not only promote the formation of calcium titanate, but also facilitate the reduction of iron minerals in the reduction products. The optimum reduction time was 180min under the conditions of CaCO3 dosage of 18wt%, reduction temperature of 1400℃ and lignite dosage of 70wt%. The reduced iron (Fe grade of 90.95wt%, Fe recovery of 92.21wt%) and calcium titanate were obtained via grinding-magnetic separation. Moreover, calcium titanate prepared via the direct reduction method could be used as a photocatalyst, where the degradation degree of methylene blue increased from 25.13% to 60.14% with the addition of calcium titanate. Furthermore, Langmuir Hinshelwood fitting results indicated that the degradation of methylene blue by the calcium titanate prepared under different reduction times conformed to first-order reaction kinetics, where the photocatalytic degradation rate of methylene blue was noted to be the highest for a reduction time of 180 min.

3

Effects of Temperature on Fe and Ti in Carbothermic Reduction of Vanadium Titanomagnetite with adding MgO

Li Xiaohui, Kou Jue, Sun Tichang, Wu Shichao, Zhao Yongqiang

Physicochemical Problems of Mineral Processing

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2019

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Vol. 55, iss. 4

917--927

EN

Effects of temperature on Fe and Ti in carbothermic reduction of vanadium titanomagnetite (VTM) concentrate with adding MgO at 1100~1500℃ were investigated. It was found that most of Fe in the VTM concentrate existed in the form of magnetite and a small amount existed as ilmenite; Ti in the VTM concentrate was mainly present in the form of ilmenite. The temperature had significant effects on Fe and Ti: increasing temperature was beneficial to decrease the Fe content in the magnesium titanate mixture, and the Fe content could decrease to 5.47% at 1500℃. Thermodynamic analysis showed that FeTiO3 and MgO preferentially reacted to form Mg2TiO4, followed by MgTiO3 and MgTi2O5 when the temperature increased from 1100℃ to 1500℃. Results of X-ray diffraction and scanning electron microscopy-energy dispersive spectroscopy analyzes showed that an intermediate product of MgFe2O4 would formed at 1300~1400℃ in the actual experiment. This caused the Fe content in the magnesium titanate mixture to increase from 21.32% to 22.85% when the temperature increased from 1200℃ to 1400℃. In addition, the size of magnesium titanate particles could increase from a few microns to approximately 100 µm when the temperature increased from 1100℃ to 1500℃, which was conducive to realize the separation of metallic iron and magnesium titanate.