A novel process was developed for the decomposition of vanadium slag using KOH sub-molten salt under ambient pressure, and the effects of reaction temperature, alkali-to-ore mass ratios, particle size, and stirring sp...A novel process was developed for the decomposition of vanadium slag using KOH sub-molten salt under ambient pressure, and the effects of reaction temperature, alkali-to-ore mass ratios, particle size, and stirring speed on vanadium and chromium extraction were studied. The results suggest that the reaction temperature and KOH-to-ore mass ratio are more influential factors for the extraction of vanadium and chromium. Under the optimal reaction conditions （temperature 180 °C, initial KOH-to-ore mass ratio 4：1, stirring speed 700 r/min, gas flow 1 L/min, and reaction time 300 min）, vanadium and chromium extraction rates can reach up to 95% and 90%, respectively. Kinetics analysis results show that the decomposing process of vanadium slag in KOH sub-molten salt can be well interpreted by the shrinking core model under internal diffusion control. The apparent activation energies for vanadium and chromium are 40.54 and 50.27 kJ/mol, respectively.展开更多
The thermal decomposition kinetics of high iron gibbsite ore was investigated under non-isothermal conditions.Popescu method was applied to analyzing the thermal decomposition mechanism.The results show that the most ...The thermal decomposition kinetics of high iron gibbsite ore was investigated under non-isothermal conditions.Popescu method was applied to analyzing the thermal decomposition mechanism.The results show that the most probable thermal decomposition mechanism is the three-dimensional diffusion model of Jander equation,and the mechanism code is D3.The activation energy and pre-exponential factor for thermal decomposition of high iron gibbsite ore calculated by the Popescu method are 75.36 kJ/mol and 1.51×10-5 s-（-1）,respectively.The correctness of the obtained mechanism function is validated by the activation energy acquired by the iso-conversional method.Popescu method is a rational and reliable method for the analysis of the thermal decomposition mechanism of high iron gibbsite ore.展开更多
The thermal decomposition of abietic acid in air was investigated under non-isothermal condition using thermogravimetric analysis-differential thermal analysis （TGA-DTA） technique with heating rates of 5, 10, 15 and...The thermal decomposition of abietic acid in air was investigated under non-isothermal condition using thermogravimetric analysis-differential thermal analysis （TGA-DTA） technique with heating rates of 5, 10, 15 and 25 K.min-~. The non-isothermal kinetic parameters were obtained via the analysis of the thermogravimetric and differential thermogravimetric （TG-DTG） curves by using Flynn-Wall-Ozawa method and Kissinger method. The thermal decomposition mechanism of abietic acid was studied with four integral methods （Satava-Sestak, MacCallum-Tanner, ordinary integral and Agrawal）. The results show that the thermal decomposition mechanism is nu- cleation and growth, and the mechanism function is Avrami-Erofeev equation with n equates 1/2. The activation energy and the pre-exponential factor are 64.04 kJ.mol^-1 and 5.89×10^5 s^-1, respectively.展开更多
基金Project(2013CB632605)supported by the National Basic Research Development Program of ChinaProjects(51274178,51274179)supported by the National Natural Science Foundation of China
文摘A novel process was developed for the decomposition of vanadium slag using KOH sub-molten salt under ambient pressure, and the effects of reaction temperature, alkali-to-ore mass ratios, particle size, and stirring speed on vanadium and chromium extraction were studied. The results suggest that the reaction temperature and KOH-to-ore mass ratio are more influential factors for the extraction of vanadium and chromium. Under the optimal reaction conditions （temperature 180 °C, initial KOH-to-ore mass ratio 4：1, stirring speed 700 r/min, gas flow 1 L/min, and reaction time 300 min）, vanadium and chromium extraction rates can reach up to 95% and 90%, respectively. Kinetics analysis results show that the decomposing process of vanadium slag in KOH sub-molten salt can be well interpreted by the shrinking core model under internal diffusion control. The apparent activation energies for vanadium and chromium are 40.54 and 50.27 kJ/mol, respectively.
基金Project(51374058)supported by the National Natural Science Foundation of China
文摘The thermal decomposition kinetics of high iron gibbsite ore was investigated under non-isothermal conditions.Popescu method was applied to analyzing the thermal decomposition mechanism.The results show that the most probable thermal decomposition mechanism is the three-dimensional diffusion model of Jander equation,and the mechanism code is D3.The activation energy and pre-exponential factor for thermal decomposition of high iron gibbsite ore calculated by the Popescu method are 75.36 kJ/mol and 1.51×10-5 s-（-1）,respectively.The correctness of the obtained mechanism function is validated by the activation energy acquired by the iso-conversional method.Popescu method is a rational and reliable method for the analysis of the thermal decomposition mechanism of high iron gibbsite ore.
基金Supported by the National＇Natural Science Foundation of China （20976031, 31060102）, the Natural Science Foundation of Guangxi Autonomous Region （2011GXNSFD018011,0991030, 2010GXNSFA013042）, the Science and Technology Program Foundation of Wuzhou City （200901011）, the Scientific and Technological Project of Guangxi （1099060-2）, the Scientific Research Innovative Foundation of Doctor Candidate （105930901008）.
文摘The thermal decomposition of abietic acid in air was investigated under non-isothermal condition using thermogravimetric analysis-differential thermal analysis （TGA-DTA） technique with heating rates of 5, 10, 15 and 25 K.min-~. The non-isothermal kinetic parameters were obtained via the analysis of the thermogravimetric and differential thermogravimetric （TG-DTG） curves by using Flynn-Wall-Ozawa method and Kissinger method. The thermal decomposition mechanism of abietic acid was studied with four integral methods （Satava-Sestak, MacCallum-Tanner, ordinary integral and Agrawal）. The results show that the thermal decomposition mechanism is nu- cleation and growth, and the mechanism function is Avrami-Erofeev equation with n equates 1/2. The activation energy and the pre-exponential factor are 64.04 kJ.mol^-1 and 5.89×10^5 s^-1, respectively.
