Papers by Author: Yan Fang Han

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Authors: Jian Hua Liu, Jing Long Chu, Tian Yan Xue, Yan Fang Han, Tao Qi
Abstract: In order to reduce the silicon content to the maximum allowed value for the production of high-purity titanium dioxide, a hydrometallurgical process on the desiliconization during alkaline leaching of titanium slag under atmospheric pressure was studied. The effect of leaching temperature, initial NaOH concentration, leaching time and mass ratio of alkali to slag, on the efficiency of silicon removal were investigated. The results show that when the mass concentration of NaOH is 30%, mass ratio of alkali to slag 3:1, the leaching temperature 120°C and the retention time about 120min, the content of silicon in solid is reduced to 0.45%. Simultaneously, the content of aluminum is reduced to 1.62%, without affecting the content of titanium. The kinetics on the desiliconization during alkaline leaching of titanium slag was carried out. The results show that under the leaching parameters mentioned above, the apparent activation energy is calculated to be 45.43kJ/mol.
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Authors: Yan Fang Han, Ti Chang Sun, Jie Li, Li Na Wang, Tian Yan Xue, Tao Qi
Abstract: NaOH solution was utilized in the molten salt reaction of titanium slag for investigating desiliconization effects. The thermodynamic behaviors of Si in the reaction system was examined to explore the impacts of molten salt reaction conditions on the conversion rates of the foreign substance Si and the target element Ti. On this basis, the influences of NaOH concentration, liquid-solid ratio, cleaning temperature and cleaning time on Si removing rate were discussed. The experimental results showed that, Si reacted with NaOH to produce sodium silicate was feasible in terms of thermodynamics within the temperature interval 400-1000K. 3Na2O•2SiO2, 2Na2O•SiO2 could stably exist under high reaction temperature. As the reaction time extended and temperature rose, the conversion rate of Si was increasing. In the process of Si removing by NaOH cleaning of molten salt reaction products, as NaOH concentration, liquid-solid ratio, cleaning temperature and cleaning time increased, Si removing rate became larger. The optimum alkali cleaning conditions were: NaOH concentration 150g/l, liquid-solid ratio 3:1, cleaning temperature 50°C and cleaning time 60min, then the desiliconization rate reached 61.16%.
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