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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.


Zhang L.-H.,Yunnan Provincial Key Laboratory of Intensification Metallurgy | Zhang L.-H.,Key Laboratory of Unconventional Metallurgy | Zhang L.-H.,National Local Joint Laboratory of Engineering Application of Microwave Energy and Equipment Technology | Zhang L.-H.,Kunming University of Science and Technology | And 20 more authors.
RSC Advances | Year: 2014

The extraction and separation of cobalt from sulphate solution containing Ni2+ and Co2+ by the process of microfluidic extraction was investigated on a counter-current flow interdigital micromixer with channels of 40 μm width, which has two opposite inlets and an upwards outlet. Meanwhile, the comparative batch extraction experiments were conducted in separatory funnels. The effects of pH and flow rates or contact time on the microfluidic and batch experiments were studied using an aqueous solution containing 73.09 g L-1 of nickel and 2.44 g L-1 of cobalt and 20 vol% PC88A diluted with 260# solvent naphtha. In addition, cobalt extraction isotherms (Mc-Cabe Thiele) were constructed to determine the number of stages. The results of percentage extraction and separation factor of microfluidic extraction was better than that of batch extraction. The features of the microreactors, i.e. large specific surface area and short diffusion distance were effective for the efficient extraction and separation of cobalt from nickel. This journal is © the Partner Organisations 2014.


Yin S.-H.,Kunming University of Science and Technology | Yin S.-H.,Key Laboratory of Unconventional Metallurgy | Yin S.-H.,National Local Joint Laboratory of Engineering Application of Microwave Energy and Equipment Technology | Yin S.-H.,Yunnan Provincial Key Laboratory of Intensification Metallurgy | And 16 more authors.
RSC Advances | Year: 2015

The aqueous solution behavior and extraction mechanism of single Nd(III) from a chloride medium with di-(2-ethylhexyl) phosphoric acid (D2EHPA, H2A2) in the presence of the complexing agent lactic acid (HLac) have been reported. The analyses by FT-IR and UV of the aqueous solution indicate that there is a coordination mechanism between Nd3+ and Lac- in the form of the carboxyl oxygen bridge bidentate ligand. A cation extraction mechanism has been studied using the method of slope analysis and saturation loading capacities, and also confirmed by FT-IR and NMR. The equilibrium constants and thermodynamic functions have been calculated. The separation factors of La/Ce, Ce/Pr and Pr/Nd are 3.24, 2.04 and 1.58, indicating that this system is beneficial for separating light rare earths. The results could provide some reference value for complexing extraction systems. © The Royal Society of Chemistry 2015.


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.


Zhang L.,Kunming University of Science and Technology | Zhang L.,National Local Joint Laboratory of Engineering Application of Microwave Energy and Equipment Technology | Zhang G.,Kunming University of Science and Technology | Zhang G.,National Local Joint Laboratory of Engineering Application of Microwave Energy and Equipment Technology | And 6 more authors.
Journal of Sol-Gel Science and Technology | Year: 2016

Abstract: We prepared the carboxymethyl-dithiocarbamate-functionalized silica nanoparticle for detecting silver ions in aqueous media. The functionalized silica nanoparticles were characterized by X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, transmission electron microscopy and thermogravimetric analysis. The functionalized silica nanoparticles realize highly sensitive and selective detection for Ag+ in aqueous solution with an apparent color change over a pH range of 4–6 and under interfering ions. The functionalized silica nanoparticles allow fast detection for Ag+ at 90 °C with a low minimum detectable concentration (0.09 mM). And a remarkable color change also occurs in the presence of Ag+ solutions containing EDTA. This developed technique can easy and fast detect silver ions by the naked eye without using any sophisticated instrumentation. Graphical Abstract: [Figure not available: see fulltext.] © 2016 Springer Science+Business Media New York


Zhang L.,Kunming University of Science and Technology | Zhang L.,National Local Joint Laboratory of Engineering Application of Microwave Energy and Equipment Technology | Liu Y.,Kunming University of Science and Technology | Liu Y.,National Local Joint Laboratory of Engineering Application of Microwave Energy and Equipment Technology | And 6 more authors.
Journal of Porous Materials | Year: 2016

Activated carbon (AC) was modified via grafting quaternary ammonium for the selective adsorption of sodium dodecyl benzene sulfonate (SDBS) from aqueous solution. The surface modification of AC was confirmed by FT-IR, XPS and Raman spectroscopy. The results showed that the modified AC selectively adsorbed the anionic SDBS. Adsorption kinetics could be well described by pseudo-second-order kinetic equation (or three-stage intraparticle diffusion mode), adsorption isotherms fitted well with Langmuir model. Quaternary ammonium on AC enhanced electropositivity and led to the selective adsorption of SDBS. © 2016 Springer Science+Business Media New York


Liu C.-H.,Yunnan Provincial Key Laboratory of Intensification Metallurgy | Liu C.-H.,National Local Joint Laboratory of Engineering Application of Microwave Energy and Equipment Technology | Liu C.-H.,Kunming University of Science and Technology | Zhang L.-B.,Yunnan Provincial Key Laboratory of Intensification Metallurgy | And 13 more authors.
Transactions of Nonferrous Metals Society of China (English Edition) | Year: 2013

The permittivity of low grade Panzhuhua ilmenite ore at 2.45 GHz in the temperatures from 20 °C up to 100 °C was measured using the technology of open-ended coaxial sensor combined with theoretical computation. The results show that both the real (ε′ and imaginary (ε″) part of complex permittivity (ε′jε″ of the ilmenite significantly increase with temperature. The loss tangent (tan δ) is a quadratic function of temperature, and the penetration depth of ilmenite decreases with temperature increase from 20 °C to 100 °C. The increase of the sample temperature under microwave radiation displays a nonlinear relationship between the temperature (T) and microwave heating time (t). The positive feedback interaction between complex permittivity and sample temperature amplifies the interaction between ilmenite and the microwave radiation. The optimum dimensions for uniform heat deposition vary from 10 cm to 5 cm (about two power penetration depths) in a sample being irradiated from both sides in a 2.45 GHz microwave field when temperature increases from room temperature to 100 °C. © 2013 The Nonferrous Metals Society of China.


Zhang L.,Kunming University of Science and Technology | Zhang L.,National Local Joint Laboratory of Engineering Application of Microwave Energy and Equipment Technology | Liu Y.,Kunming University of Science and Technology | Liu Y.,National Local Joint Laboratory of Engineering Application of Microwave Energy and Equipment Technology | And 6 more authors.
RSC Advances | Year: 2015

An activated carbon-based multicarboxyl adsorbent has been synthesized for selective removal of cationic dyes from aqueous solutions. The adsorbent was characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), N2 adsorption measurement and zeta potential. The adsorption behavior of cationic rhodamine 6G on the activated carbon-based multicarboxyl adsorbent from an aqueous medium was studied by varying the parameters such as pH, contact time and initial dye concentration. Dye adsorption was dramatically dependent on solution pH and the optimum pH is 4.45. After being modified by multicarboxyls, the adsorption capacity of rhodamine 6G on the activated carbon dramatically increased from 33.18 mg L-1 to 122.55 mg L-1 at pH 4.45. The multicarboxyl adsorbent has obvious selectivity to cationic dyes. Adsorption isotherms could be well described by the Langmuir model, adsorption kinetics fitted well with a pseudo-second-order kinetic equation and exhibited a 3-stage intraparticle diffusion mode. The electrostatic interaction was the main mechanism for the cationic dye adsorption. © 2015 The Royal Society of Chemistry.


Cheng S.,Kunming University of Science and Technology | Cheng S.,National Local Joint Laboratory of Engineering Application of Microwave Energy and Equipment Technology | Zhang L.,Kunming University of Science and Technology | Zhang L.,National Local Joint Laboratory of Engineering Application of Microwave Energy and Equipment Technology | And 8 more authors.
RSC Advances | Year: 2016

A composite adsorbent (Fe-activated carbon) was synthesized by impregnating Fe(NO3)3 onto activated carbon, and heated via microwave heating to remove methylene blue (MB), utilizing ultrasound-microwave combined preparation methods. The optimal MB removal capacity and yield of Fe-activated carbon is 257 mg g-1 and 83.31%, respectively, under optimal conditions such as 700 W of microwave power, 700 °C of temperature and 25 min of heating time. The ultrasound was used for assisted-impregnation of Fe(NO3)3 onto the activated carbon via its acoustic cavitation. The removal capacity on MB of Fe-activated carbon increases by 17.12%, as compared to that of it without ultrasound assisted-impregnation. The physico-chemical properties of Fe-activated carbon were examined by XRD, XPS, SEM, EDX, FTIR, Raman and N2 adsorption. Moreover, the existence of Fe3O4 leads to Fe-activated carbon having magnetic properties, which makes it easily separable from dyes wastewater in an external magnetic field. The equilibrium adsorption data showed that the adsorption behavior followed the Langmuir isotherm, and a pseudo-second order model matched well the kinetic data. Compared with raw activated carbon, the maximum monolayer adsorption capacity of Fe-activated carbon increases by 25.96%. According to these results, Fe-activated carbon is a promising adsorbent for the removal of dye from wastewater. © 2016 The Royal Society of Chemistry.

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