Hechi College

Yizhou, China

Hechi College

Yizhou, China
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Li X.-H.,Guangxi University | Zhang Y.-J.,Guangxi Research Institute of Chemical Industry | Pan L.-P.,Guangxi University | Wei Y.-S.,Hechi College
Transactions of Nonferrous Metals Society of China (English Edition) | Year: 2013

Neutral leach residue of zinc calcine (NLRZC) was mechanically activated by a stirring ball mill. Subsequently, the changes in physicochemical properties and dissolution kinetics in sulphuric acid were studied. The crystalline structure, morphology, particle size and specific surface area of the non-activated and mechanically activated NLRZC were characterized by X-ray diffraction, scanning electron microscope, particle size analyzer and volumetric adsorption analyzer, respectively. The characterization results indicate that mechanical activation (MA) induced remarkable changes in the physicochemical properties of NLRZC. The leaching experiments show that MA significantly enhances the leaching reactivity of NLRZC using the zinc extraction as evaluating index. After NLRZC is mechanically activated for 30 min and 60 min, the activation energy decreases from 56.6 kJ/mol of non-activated NLRZC to 36.1 kJ/mol and 29.9 kJ/mol, respectively. The reaction orders of the non-activated, 30 and 60 min activated NLRZC dissolution with respect to H2SO 4 concentration were found to be 0.34, 0.30, and 0.29, respectively. © 2013 The Nonferrous Metals Society of China.


Li X.-H.,Guangxi University | Zhang Y.-J.,Guangxi University | Qin Q.-L.,Guangxi University | Yang J.,Guangxi University | Wei Y.-S.,Hechi College
Transactions of Nonferrous Metals Society of China (English Edition) | Year: 2010

Indium was recovered from zinc oxide flue dust (ZOFD) with sulfuric acid by oxidative pressure leaching in an autoclave, and the effects of different technological conditions on indium leaching were studied. Potassium permanganate and hydrogen peroxide were used as oxidants. The atmospheric pressure leaching experiments were also carried out. The experimental results show that the leaching rate of indium can be effectively improved by oxidative pressure leaching. The optimum conditions of pressure leaching are determined as sulfuric 5.10 mol/L acid, leaching time 150 min, temperature 90 °C, and the H 2O2 dosage of 0.5 mL/g or 2.5% KMnO4. The leaching rate of indium is more than 90%, which is increased by 13% compared with that of atmospheric pressure leaching process without oxidant under the optimum conditions.


Zhang Y.,Guangxi University | Li X.,Guangxi University | Pan L.,Guangxi University | Wei Y.,Hechi College | Liang X.,Guangxi University
Hydrometallurgy | Year: 2010

The synthetic indium-bearing zinc ferrite (IBZF) was mechanically activated by a stirring ball mill and subsequently studied for the leaching behavior and kinetics of extracting indium from IBZF. The effect of the change in crystalline phase, lattice distortion, particle size, specific surface area and morphology introduced by mechanical activation (MA) was also investigated. The activated IBZF showed different physicochemical characteristics and was found to be easier to dissolve in sulphuric acid than the unmilled sample. MA enhanced the leaching reactivity of IBZF. When IBZF was mechanically activated for 30 and 60 min, the activation energy decreased from 68.8 kJ/mol to 54.4 and 44.7 kJ/mol, respectively. The leaching process of unmilled IBZF was controlled by chemical reaction, but became the hybrid controlled process after MA. The reaction orders of the unmilled, activated for 30 and 60 min IBZF dissolution with respect to H2SO4 concentration were 0.69, 0.58, and 0.54, respectively. © 2010 Elsevier B.V. All rights reserved.


Huang Y.-H.,Guangxi University | Huang Y.-H.,Hechi College | Tong Z.-F.,Guangxi University | Liao S.,Guangxi University | And 3 more authors.
Gao Xiao Hua Xue Gong Cheng Xue Bao/Journal of Chemical Engineering of Chinese Universities | Year: 2010

The precursor NH4CoPO4 was synthesized firstly via the solid-state reaction at low-heating temperature with lithium hydroxide, ammonium dihydrogen phosphate and cobalt acetate as raw materials in the present of PEG-400. Then the nano-crystallite LiCoPO4 powder was successfully obtained via the solid-state reaction of the prepared precursor at high temperature. The products were characterized with XRD, FT-IR and SEM, and the results show that, in the high temperature solid-state reaction, the precursor NH4CoPO4 is quickly reacted to form amorphous intermediates. The formation of LiCoPO4 via solid phase reaction undergoes a series of complex kinetic competitive process. The Co2P2O7, Li3PO4 and LiCoPO4 accrete in the products, and the transform reaction of Li3PO4 follows the index nucleation reaction mechanism with the active energy of 41.8 kJ·mol-1 which is the control step of the solid-state reaction. The formation reactions of LiCoPO4 and Co2P2O7 can be described by power law mechanism model, and there exists a transform reaction transforming Co2P2O7 to LiCoPO4. The above transforming reaction agrees with the Avrami-erofeev mechanism model of reaction controlled by the phase-boundary reaction of constant rate nucleation and two-dimensional nuclear growth with the reaction order n=3. Furthermore, the transform reaction from Co2P2O7 to LiCoPO4 is promoted by high temperature, but the size of the sample particles increases, which will impede further proceeding of the reaction.


Zhang L.,Guangxi University | Huang H.,Hechi College | Tong Z.,Guangxi University
Huaxue Fanying Gongcheng Yu Gongyi/Chemical Reaction Engineering and Technology | Year: 2010

The fiber felty V2O5/TiO2/carbon catalyst was prepared by supporting V2O5 on TiO2 film coated with activated carbon fiber felt (ACF) under ultrasonic irradiation and was characterized by means of X-ray diffraction (XRD) and scanning electron microscope (SEM). The effects of V2O5 and TiO2 loading on selective catalytic reduction (SCR) of NO were investigated. The results showed that compared with powdered V2O5/TiO2, fiber felty V2O5/TiO2/carbon-based catalyst exhibited better low temperature activity due to ACF skeleton, and TiO2 loading had no significant effect on SCR activity while SCR activity increased with the increase of V2O5 loading. Conversion of NO reached 84.26% under the conditions of TiO2 loaded 2%, V2O5 loaded 9%, reaction temperature 280 °C and gas hourly space velocity 5 000 h-1.


Zhang Y.-J.,Guangxi University | Li X.-H.,Guangxi University | Pan L.-P.,Guangxi University | Wei Y.-S.,Hechi College
Zhongguo Youse Jinshu Xuebao/Chinese Journal of Nonferrous Metals | Year: 2012

The synthetic indium-bearing zinc ferrite (IBZF) was mechanically activated by a stirring ball mill. The leaching behavior and dissolution kinetics of nonactivated as well as activated IBZF samples in sulphuric acid solution were investigated by using the zinc extraction as evaluating index. The influences of mechanical activation on the crystal structure, morphology, particle size and specific surface area were also characterized by means of X-ray diffractometer (XRD), scanning electron microscope (SEM), laser diffraction particle size analyzer and specific surface area analyzer. The results show that the physicochemical properties of IBZF are changed obviously by mechanical activation and thus enhance the reactivity of IBZF. When IBZF is mechanically activated for 30 and 60 min, the apparent activation energy decreases from 76.4 kJ/mol to 58.6 and 51.8 kJ/mol, respectively, the reaction order also decreases from 0.79 to 0.62 and 0.59. The acid leaching process of nonactivated IBZF is controlled by chemical reaction, but becomes the hybrid controlled process after mechanical activation.


Zhang Y.J.,Guangxi University | Li X.H.,Guangxi University | Pan L.P.,Guangxi University | Wei Y.S.,Hechi College
Advanced Materials Research | Year: 2011

This study was concerned with the effects of mechanical activation (MA) on structural characterization for neutral leach residue of zinc calcine (NLR) and kinetics of indium extraction from NLR in sulphuric acid. The X-ray diffraction (XRD) analysis showed that MA caused the decrease in crystalline phase and increase in lattice distortion. The activation time, reaction temperature and H 2SO 4 concentration had positive effect on indium extraction from NLR. The activation energies of the unactivated, milled for 30 and 60 min NLR samples calculated for indium extraction were 39.3, 32.1, and 30.4 kJ/mol, respectively, which indicated that MA increased the leaching kinetics of indium extraction from NLR. The empirical orders of the unactivated, activated for 30 and 60 min samples for extracting indium with respect to H 2SO 4 concentration were 0.52, 0.51, and 0.51, respectively. © (2011) Trans Tech Publications.


Lin Y.,Hechi College | Feng C.,Guangxi Normal University
Communications in Computer and Information Science | Year: 2011

In this paper, a system of three coupled oscillators with delays is investigated. Some sufficient conditions to guarantee the existence of stability and oscillations for the model are obtained. Simulations are provided to demonstrate the proposed results. © 2011 Springer-Verlag.


Feng C.,Guangxi Normal University | Lin Y.,Hechi College
Applied Mechanics and Materials | Year: 2011

In this paper, we discuss a system of four coupled oscillators with delays. Some sufficient conditions to guarantee the existence of oscillations for the model are obtained. Computer simulations are provided to demonstrate the present results. © (2011) Trans Tech Publications, Switzerland.

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