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Niu L.,Northeastern University China | Niu L.,Key Laboratory for Ecological Utilization of Multimetallic Mineral | Zhang T.,Northeastern University China | Zhang T.,Key Laboratory for Ecological Utilization of Multimetallic Mineral | And 8 more authors.
Xiyou Jinshu Cailiao Yu Gongcheng/Rare Metal Materials and Engineering | Year: 2014

The thermodynamics and kinetics of natural rutile carbochlorination have been investigated in a fluidized-bed. Thermodynamic analysis of this system reveals that when C is excess in the solid phase, TiCl4 and CO are the only two stable products in the chemical equilibrium compositions system, and the increase of the ratio of C to TiO2 has little effect on the product composition. At high temperature, the reaction with CO as the product is the dominant reaction. This paper proposed a reaction rate model, and got a rutile chlorination rate formula, which is more consistent with experimental data. For the TiO2-C-Cl2 system, the reaction rate is dependent on both size and density of natural rutile. From 900 to 1000°C, the apparent activation energy is 10.569 kJ/mol. In this temperature range, mass diffusion is the main reaction controlling step. The expression of the chlorine reaction rate in the C-Cl2 system was obtained, and it depends on the degree of reaction, Cl2 concentration and the size of coke. Source


Niu L.-P.,Northeastern University China | Niu L.-P.,Key Laboratory for Ecological Utilization of Multimetallic Mineral | Zhang T.-A.,Northeastern University China | Zhang T.-A.,Key Laboratory for Ecological Utilization of Multimetallic Mineral | And 6 more authors.
Zhongguo Youse Jinshu Xuebao/Chinese Journal of Nonferrous Metals | Year: 2013

The molten magnesium chloride, from reduction-distillation process in Kroll method of titanium metallurgy, was used to produce ultra fine magnesia powder under the condition of oxygen by direct pyrolysis. The effects of pyrolysis temperature, pyrolysis time and oxygen pressure on the pyrolysis efficiency of molten MgCl2 were investigated. The single factor experiments show that the optimum reaction conditions are as follows: pyrolysis temperature 1000°C, pyrolysis oxygen partial pressure 0.08 MPa and pyrolysis time 50 min. The pyrolysis rate of molten MgCl2 can reach 93.5% under the optimum conditions. The obtained MgO powder was analyzed by XRD and SEM. These MgO powders, showing an irregular hexahedral shape, have an average diameter of 80-100 nm with uniform size distribution, good dispersity and high purity. The dynamic study of pyrolysis reaction show that this reaction is controlled by chemical reaction at the initial stage of reaction, with the apparent activation energy Ea=93.7 kJ/mol. At the later reaction stage, both diffusion and chemical reaction become the restricting factors with the apparent activation energy Ea=26.3 kJ/mol. Source


Zhihe D.,Key Laboratory for Ecological Utilization of Multimetallic Mineral | Ting-An Z.,Key Laboratory for Ecological Utilization of Multimetallic Mineral | Hanbo Z.,Key Laboratory for Ecological Utilization of Multimetallic Mineral | Zhiqi Z.,Key Laboratory for Ecological Utilization of Multimetallic Mineral | And 3 more authors.
Ti 2011 - Proceedings of the 12th World Conference on Titanium | Year: 2012

Rutile, ilmenite and Al-Ca complex reducer were used to prepare high titanium ferrous alloy by enhanced reduction-SHS method. The thermodynamic of the relative reactions was studied. The effects of the composition of complex A-Ca reducer on the enhanced reduction-SHS process were investigated and the high titanium ferrous alloys were characterized by XRD, SEM. The results indicate that the adiabatic temperatures of the Ca reducing reaction systems are higher than 1800K so all the reactions can keep on carrying on by self. The adiabatic temperatures and reaction heat effects of the Ca reducing reaction systems are higher than those of the Al Ca reducing reaction systems, so there are more fully reaction conditions during the reducing reaction process by A-Ca complex reducer. The high titanium ferrous alloys consist mainly of TiFe2, AlTi3 and oxide inclusions. The oxide inclusions exist in the alloy which results directly in the high oxygen content and micro-structural defects. The lowest oxygen content in the alloy is lower than 1.0% which is removed effectively. Source

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