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Xu L.,Kunming University of Science and Technology | Xu L.,Key Laboratory of Unconventional Metallurgy | Yan M.,Kunming University of Science and Technology | Yan M.,Key Laboratory of Unconventional Metallurgy | And 13 more authors.
Journal of Alloys and Compounds | Year: 2014

Cu-W alloy was prepared by utilizing microwave vacuum infiltration sintering furnace to assess the influence of different proportions of copper on the structure of Cu-W alloy. The microstructures of alloy and infiltration characteristics of Cu-W alloy were characterized using metallographic microscopy and scanning electron microscopy, while XRD was utilized to identify the structure changes. The pore distribution was also assessed. Experimental results showed that Cu-W alloy could be quickly prepared under vacuum conditions through microwave infiltration sintering with the main phase of alloy being Cu0.4W0.6 (PDF:50-1451) indicating stronger combination of tungsten and copper. © 2013 Elsevier B.V. All rights reserved.


Shang X.,Kunming University of Science and Technology | Shang X.,Key Laboratory of Unconventional Metallurgy | Shang X.,National Local Joint Laboratory of Engineering Application of Microwave Energy and Equipment Technology | Chen J.,Kunming University of Science and Technology | And 2 more authors.
High Temperature Materials and Processes | Year: 2016

This paper proposes an analytical approach to optimize the thickness of refractories for achieving maximum microwave power transmission in microwave heating based on the analysis of power transmission coefficient (PTC). The microwave PTCs of alumina (Al2O3) ceramics over the temperature range of 22-1,379°C at 2,450 MHz, mullite ceramics in the temperature range of 27-1,027°C at 2.45 GHz and 400-1,300°C at 915 MHz are studied. The results show that there are several transmission peaks in the PTC patterns. The transmission peak amplitude depends sensitively on the thickness of the refractory and the peak shifting towards a smaller thickness as the temperature of the refractory increases. We also show that high microwave transmission can only be achieved in a refractory with a small thickness corresponding to a slight transmission peak shift in the entire microwave heating (less than one eighth wavelength in the refractory). © 2016 by De Gruyter.


Yin S.-H.,Kunming University of Science and Technology | Yin S.-H.,Key Laboratory of Unconventional Metallurgy | Li S.-W.,Kunming University of Science and Technology | Li S.-W.,Key Laboratory of Unconventional Metallurgy | And 6 more authors.
RSC Advances | Year: 2014

In order to develop a novel separation technology superior to the current extraction systems, the extraction behaviors of Ce(iii) and Pr(iii) from chloride medium with P204 in the presence of two complexing agents lactic acid (LA) and citric acid (H3cit) have been reported. The distribution ratios increase with the increase of the equilibrium pH and the ratio of [H3cit]:[LA] under certain conditions. The separation factors of Ce(iii) and Pr(iii) increase with the ratio of [H3cit]:[LA] at fixed pH, and the maximum value is as high as 5.78 in this complexing system. The maximum saturated extraction capacity is 27.08 g L-1 which is close to that in the current saponified P507 extraction system. The equilibrium constants and thermodynamic functions, ΔG, ΔH and ΔS have been calculated. Lactic acid and citric acid can be effectively recycled and enriched, providing possibilities for dissolving minerals in the circular process. By comparison with the experimental results, this complexing extraction method could be regarded as an effective strategy for separating REs. © The Royal Society of Chemistry 2014.


Chen G.,Key Laboratory of Unconventional Metallurgy | Chen G.,Kunming University of Science and Technology | Chen J.,Key Laboratory of Unconventional Metallurgy | Chen J.,Kunming University of Science and Technology | And 2 more authors.
Metalurgia International | Year: 2011

Temperature rising characteristics of titania-rich slag under microwave irradiation were obtained. The effects of microwave power, mean particle sizes of samples and sample weight on temperature rising characteristics of titania-rich slag were systematically investigated. The crystalline compounds of sample before and after microwave heating were characterized by X-ray diffractometry. The results show that the titania-rich slag has a good microwave absorption property. The titania-rich slag sample can be reach 1200 °C after 60 min at 3.0 kW in microwave field. The XRD characterization results show that untreated titania-rich slag mainly consists of crystalline compounds of anatase TiO2 phase; while the microwave heating treated sample is mainly composed of crystalline compounds of rutile TiO2 phase. It can be inferred that anatase TiO2 phase is completely converted to rutile TiO2 phase in microwave heating.


Chen G.,Key Laboratory of Unconventional Metallurgy | Chen G.,Kunming University of Science and Technology | Chen J.,Key Laboratory of Unconventional Metallurgy | Chen J.,Kunming University of Science and Technology | And 2 more authors.
Metalurgia International | Year: 2011

In this paper, the effects of mechanical activation on the microwave absorbing characteristics of ilmenite were systematically investigated using the microwave cavity perturbation technique and the digital signal processing technique. The relationships between dielectric loss and the microwave absorbing characteristics of the mechanical activated ilmenite were studied. The crystal structures and surface chemical functional groups of ilmenite were characterized using XRD and FT-IR, respectively. The results indicated that the microwave absorbing characteristics of mechanical activated ilmenite are better than that of untreated ilmenite. The optimum experiment parameters were found as follows: mechanical activation time of 120 min.


Chen G.,Key Laboratory of Unconventional Metallurgy | Chen G.,Kunming University of Science and Technology | Chen J.,Key Laboratory of Unconventional Metallurgy | Chen J.,Kunming University of Science and Technology | And 4 more authors.
Metalurgia International | Year: 2011

In this paper, preparing partially stabilized zirconia with high thermal shocking resistance properties from fused zirconia by microwave radiation was investigated. Effects of microwave irradiation temperature, and holding time on crystalline compound and microstructure of partially stabilized zirconia were evaluated. The crystal structures and microstructure of samples were characterized using XRD and SEM, respectively. Experimental results indicated that the fused zirconia have a good microwave absorption. The XRD results showed that the fused zirconia was mainly composed of cubic ZrO2 phase, but that of being treated by microwave irradiation was mainly composed of cubic ZrO2 and monoclinic ZrO2. The technical economical assessments results demonstration that the microwave irradiation techniques can be applied effectively and efficiently to the treatment processing of fused zirconia.


Lu M.-N.,Kunming University of Science and Technology | Lu M.-N.,Key Laboratory of Unconventional Metallurgy | Lu M.-N.,Engineering Laboratory of Microwave Application and Equipment Technology | Lu M.-N.,State Key Laboratory Breed Base Of Complex Nonfer Metal Rsrc Cleaning Utilization In Yunnan Province | And 13 more authors.
Hydrometallurgy | Year: 2013

This preliminary study examined the role of microwave radiation on precipitation and aging of iron oxyhydroxides at 60 C. It was observed that due to rapid heating under microwave, transformation of two line ferrihydrite to α-Fe2O3 takes place within 4-10 h. This is in contrast to the usual aging temperature of > 100 C adopted in most conventional studies, and several days of aging. Besides rapid transformation, microwave helps forming nanoparticles, with crystallite size of ~ 60 nm as determined from X-ray diffractograms, and < 100 nm particles as observed under TEM. Rapid transformation also promotes formation of α-Fe 2O3 without the formation of intermediate γ-Fe 2O3. This study brought out the advantages of low temperature microwave assisted precipitation/aging as a low energy process to transform iron oxyhydroxides, with likely applications in slurry rheology, synthesis of nanoparticles, and adsorption. © 2013 Elsevier B.V.


Yin S.,Kunming University of Science and Technology | Yin S.,Key Laboratory of Unconventional Metallurgy | Yin S.,National Local Joint Laboratory of Engineering Application of Microwave Energy and Equipment Technology | Yin S.,Yunnan Provincial Key Laboratory of Intensification Metallurgy | And 15 more authors.
Chemical Engineering and Processing: Process Intensification | Year: 2015

A new solvent extraction system of extracting La(III) with 2-ethylhexyl phosphoric acid-2-ethylhexyl ester (P507) has been investigated to intensify the extraction process in microreactor, and solve the problems like long mixing time, low processing capacity, large factory area occupation, and high energy consumption in the conventional rare earth solvent extraction equipment. In this work, extraction equilibrium studies show that the initial aqueous pH value 4.00 and saponification rate 40% are the optimal operation condition. The effects of volumetric flow rate on extraction efficiency are analyzed, and the results indicate that increasing flow ratio could improve the extraction efficiency greatly, up to almost 100%, and the two phases keep parallel flow while keeping an aqueous-organic interface in the microchannel. The mass transfer rate is proportional to the initial pH and P507 concentration, and approaches almost a constant value at high pH and extractant concentration, and the transfer process between the two phases accompanied with an interface chemical reaction is confirmed to proceed satisfactorily in a short time (residence time. =. 0.37. s). The features of the microreactors, i.e., large specific surface area and short diffusion distance are effective for the efficient extraction of La(III). © 2015 Elsevier B.V.


Yang B.,Kunming University of Science and Technology | Yang B.,Key Laboratory of Unconventional Metallurgy | Li W.,Key Laboratory of Unconventional Metallurgy | Li W.,Kunming University of Science and Technology | And 6 more authors.
Energy Procedia | Year: 2012

The higher power microwave heating source, in the industrial and engineering needs, is obtained through inputting microwave energy of multi-open feed into cavity via near-field radiation, resulting in the coupling of each feed. Meanwhile, the initial situation, the ratio of fluid and the permittivity are highly nonlinear in the process of microwave heating during technical operation process by microwave heating process cycling fluid medium. This paper is presented an improved Anti-predatory Particle Swarm Optimization (APSO) algorithm to optimize the three parameters of PID controller, and is applied to control the complicated and coupling of microwave heating. It is shown through intelligent calculation and simulation experiments that the improved APSO has good performance. And this paper provides an alternative for control of multi-couple and uncertain objects in industry. © 2011 Published by Elsevier Ltd.


PubMed | Key Laboratory of Unconventional Metallurgy and Kunming University of Science and Technology
Type: | Journal: Journal of environmental management | Year: 2017

Low-carbon ferrochrome slag (LCFS), a by-product of the ferrochrome alloy industry, has potential for use as a cementitious material due to its pozzolanic characteristic. The objective of the present study was to determine the optimum compound chemical activators for LCFS-based composite cement using an orthogonal test, in which 7d and 28d compressive strengths were used as the evaluating indices. The influences of compound chemical activators on the hydration of a composite cement mix were investigated using X-ray diffraction (XRD), scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDS) and thermogravimetry-differential scanning calorimetry (TG-DSC). The optimum activator to activate the composite cement was a compound of NaCl (NC) at a dosage of 0.6%, Na

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