Engineering Laboratory of Microwave Energy Application and Equipment Technology

Yunnan, China

Engineering Laboratory of Microwave Energy Application and Equipment Technology

Yunnan, China
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Wang X.-H.,Key Laboratory Breeding Base of Complex Nonferrous Metal Resources Cleaning Utilization in Yunnan Province | Wang X.-H.,Key Laboratory of Unconventional Metallurgy | Wang X.-H.,Engineering Laboratory of Microwave Energy Application and Equipment Technology | Peng J.-H.,Key Laboratory Breeding Base of Complex Nonferrous Metal Resources Cleaning Utilization in Yunnan Province | And 14 more authors.
Zhongnan Daxue Xuebao (Ziran Kexue Ban)/Journal of Central South University (Science and Technology) | Year: 2012

Based on the fact that the iron ore in Yunnan Huimin is mainly fine-grained impregnation structure whose major iron ore of oxide ore is limonite, the oxide ore was studied, and the iron ore was sorted with the craft of magnetization roasting-low intensity magnetic separation. The effects of the microwave roasting temperature, and the amount of reducing agent, magnetic field strength on the index of separation were investigated. The results show that the preparation concentrate grade is 59.31% and recovery is 81.92% under the condition of roasting temperature of 800°C, amount of reducing agent of 12%, reduction time of 12 min and magnetic field strength of 119.37 kA/cm. It confirms that the method of microwave magnetizing roast of iron ore is feasible, which provides a new way for the difficult separation of iron ore.


Li J.,Kunming University of Science and Technology | Li J.,Engineering Laboratory of Microwave Energy Application and Equipment Technology | Li J.,State Key Laboratory Breeding Base of Complex Nonferrous Metal Resources Cleaning Utilization | Peng J.,Kunming University of Science and Technology | And 8 more authors.
Ceramics International | Year: 2013

In this work, instead of chemical pure zirconia, natural baddeleyite was used as starting material to prepare partially stabilized zirconia (PSZ) with magnesia as stabilizer. Response surface methodology (RSM) involving central composite design (CCD) was employed to optimize the sintering process for the preparation of magnesia partially stabilized zirconia (MgO-PSZ) with the aim of improving the relative density and bending strength of the materials. The interaction between three variables i.e. sintering temperature, holding time and heating rate was studied and modeled. The statistical analysis of the results showed that in the range studied, sintering temperature had a significant effect on relative density and bending strength. The optimum combination predicted by RSM was experimentally confirmed, whereby almost complete densification with the relative density 99.44% was obtained at a 3 °C/min cooling rate. © 2012 Elsevier Ltd and Techna Group S.r.l.


Li J.,Kunming University of Science and Technology | Li J.,Engineering Laboratory of Microwave Energy Application and Equipment Technology | Li J.,State Key Laboratory Breeding Base of Complex Nonferrous Metal Resources Cleaning Utilization | Peng J.,Kunming University of Science and Technology | And 8 more authors.
Journal of Alloys and Compounds | Year: 2013

Response surface methodology (RSM) was successfully applied to process of preparation calcia partially stabilized zirconia (CaO-PSZ). Besides that, natural baddeleyite was used as starting materials instead of chemical pure zirconia. The pressureless sintering process was optimized by the application of RSM. The independent variables, which had been found as the most effective variables on the relative density and bending strength by screening experiments, were determined as holding time, sintering temperature and heating rate. Two quadratic models were developed through RSM in terms of related independent variables to describe the relative density and bending strength as the responses. Based on contour plots and variance analysis, optimum operational conditions for maximizing relative density and bending strength, at cooling rate of 3°C/min, were 1540 °C of sintering temperature, 5 h of holding time and heating rate of 3 °C/min to obtain 98.57% for relative density and 165.72 MPa for bending strength. Crown Copyright © 2013 Published by Elsevier B.V. All rights reserved.


Li J.,Kunming University of Science and Technology | Li J.,Engineering Laboratory of Microwave Energy Application and Equipment Technology | Li J.,State Key Laboratory Breeding Base | Peng J.,Kunming University of Science and Technology | And 17 more authors.
Phase Transitions | Year: 2012

The phase transformation of different polymorphs in zirconia is very important for the processing and mechanical properties of zirconia ceramics. In this work, thermodynamic description of ZrO 2-MgO system is investigated using the related thermodynamic parameters. Special attention is paid to the calculation of the Gibbs free energy change between tetragonal and monoclinic phases in ZrO 2-MgO, namely tm phase transformation driving force, as a function of composition and temperature. Furthermore, in 8.7mol% MgO-ZrO 2, the equilibrium temperature between tetragonal and monoclinic phases, T 0, was obtained as 1107.8K and martensitic transformation start temperature (M s) for t→m of this ceramic with a mean grain size of 1.15mm was also calculated to be as 737.7K, which is in good agreement with experiment one of 689.5K with 7.0% residual. © 2012 Taylor & Francis Group, LLC.


Li J.,Kunming University of Science and Technology | Li J.,Engineering Laboratory of Microwave Energy Application and Equipment Technology | Li J.,State Key Laboratory Breed Base Of Complex Nonfer Metal Rsrc Cleaning Utilization | Peng J.,Kunming University of Science and Technology | And 17 more authors.
Ceramics International | Year: 2012

The phase transformation of different polymorphs in zirconia is very important for the processing and mechanical properties of zirconia ceramics. This paper adopts thermodynamic model which is suitable for ceramic system to calculate the Gibbs free energy change of tetragonal and monoclinic phases in ZrO 2-CaO binary system. The difference of the Gibbs free energy between tetragonal and monoclinic phases in ZrO 2-CaO as a function of composition and temperature, namely t → m phase transformation driving force, is thermodynamically calculated from the binary systems. Furthermore, in 8.0 mol% CaO-ZrO 2, the equilibrium temperature between tetragonal and monoclinic phases, T 0, was obtained as 1270.3 K, and martensitic transformation starting temperature (M s) for t → m transformation of this ceramic with a mean grain size of 2.0 mm was calculated as 805.9 K, which is good agreement with experiment one of 793 K with 12.9 K residual. © 2011 Elsevier Ltd and Techna Group S.r.l.

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