State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization

Kunming, China

State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization

Kunming, China
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Cao Q.,State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization | Cao Q.,Kunming University of Science and Technology | Cheng J.,Kunming University of Science and Technology | Feng Q.,Kunming University of Science and Technology | And 3 more authors.
Powder Technology | Year: 2017

The effects of ultrasonication on the hydrophobicity of oxidized pyrite and the flotation of an oxidized pyrite ore were investigated in this work. Surface examinations show that ultrasonication (≥ 0.3 W/cm2) could result in surface cleaning and further oxidation of both slightly and heavily oxidized pyrite within 40 s. In the surface cleaning stage, the mechanical effects of ultrasonication removed the oxidation products from the pyrite surface. Further, in the surface oxidation stage, H2O2 and oxygen formed by ultrasonication immediately oxidized the pyrite, leading to a notable decrease in the contact angle. It was found that the influence of ultrasonication is governed by the time rather than the intensity of ultrasonication. Ultrasonication significantly improved the recovery of pyrite in the rougher and cleaner stages, when ultrasound was used only during flotation. The unfavorable effects of ultrasonication, such as oxidation, were not notable during flotation of the pyrite ore, due to the weak ultrasonic field in the flotation cells and the limited flotation time. Additionally, ultrasonication favored the formation of fine bubbles in the flotation cell, which is also benefit for pyrite flotation. © 2017 Elsevier B.V.


Ru J.,Kunming University of Science and Technology | Hua Y.,Kunming University of Science and Technology | Hua Y.,State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization | Wang D.,Kunming University of Science and Technology
Journal of the Electrochemical Society | Year: 2017

The effects of reaction temperature from 313 K to 353 K on the direct electro-deoxidation of solid PbO to porous lead in choline chloride-ethylene glycol deep eutectic solvent (ChCl-EG DES) are elucidated preliminarily at cell voltage 2.5 V for 4 h. Cyclic voltammetry of PbO powders on microelectrode in ChCl-EG indicates that a promotion effect of the increase in temperature is noticed on cathodic current. Constant voltage electrolysis demonstrates that the reduction degree of PbO pellet is 88.19% (in weight) at 353 K and appropriate raising of temperature can significantly facilitate the metallization of solid PbO to lead. Additionally, the morphological and crystallographic characteristics of porous lead are also clarified. Different shapes of dendrites and hexagonal crystal plates are generated at higher temperature with the predominant (111) plane of lead due to its slow growing rate. Furthermore, the direct electrolysis models of PbO pellet at lower and higher temperatures in ChCl-EG are put forward. The raising of temperature plays a crucial role in improving the reduction rate of the direct deoxidation of PbO(s)→Pb(s) and dissolution-electrodeposition of [PbO · Cl · EG]-→Pb(s). © 2017 The Electrochemical Society. All rights reserved.


Wang W.,Northeastern University China | Wu F.,The Key Laboratory of Metallurgy and Energy Conservation of Guizhou | Wu F.,State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization | Yu Q.,Northeastern University China
Russian Journal of Non-Ferrous Metals | Year: 2017

The feasibility of developing a waste heat recovery system from waste hot air generated by the reduction system in Kroll process to pre-heat water is studied in this paper, in order to reduce energy loss. In the proposed system, the hot air from reduction reactor was first collected by pipelines with insulating material, and then supplies to a shell-and-tube heat exchanger to heat up water. And the energy, exergy analysis of the whole waste heat recovery system have been carried out firstly on the basis of material, energy and exergy balance. Then, the thermo-economic analysis and economic analysis of the waste heat recovery system are also discussed. The results show that the waste heat recovery system presented in this paper could be applied not only for restricted category of reduction system in Kroll process, although the energy efficiency and exergy efficiency of the waste heat recovery system are as low as 26.84% and 11.09%, respectively. And more than two times equivalent energy could be obtained from the waste heat recovery system. The payback period of a waste heat recovery system is about 4.39 years. © 2017, Allerton Press, Inc.


Ru J.,Kunming University of Science and Technology | Hua Y.,Kunming University of Science and Technology | Hua Y.,State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization | Wang D.,Kunming University of Science and Technology
Advances in Applied Ceramics | Year: 2017

Titanium nitride (TiN) is prepared from ilmenite (FeTiO3) powders by microwave-assisted carbothermic reduction–nitridation in air atmosphere followed by acid leaching treatment. The thermal analysis of the reduction–nitridation of FeTiO3 powders is conducted by thermogravimetry/differential scanning calorimeter. The phase transition sequence of microwave carbothermal synthesis of TiN–Fe composite is: FeTiO3 → Fe + TiO2 → Fe + TiN. There is no any other oxygen-deficient titanium oxides detected. Particularly, FeTiO3 can be transformed into TiN–Fe composite completely at 900°C for 60 min by microwave heating. The increase in both the reaction temperature and dwelling time is in favour of the transformation of FeTiO3. The product morphologies are spherical about 2–5 μm in size. Then TiN is obtained with the removal of Fe and their oxides from TiN–Fe composite by acid leaching treatment. This method not only reduces the reaction temperature significantly through microwave heating but also can simplify the operation process effectively. © 2017 Institute of Materials, Minerals and Mining. Published by Taylor & Francis on behalf of the Institute


Ru J.,State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization | Hua Y.,Kunming University of Science and Technology | Li J.,State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization | Xu C.,State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization | And 4 more authors.
Journal of Molecular Liquids | Year: 2014

The effects of existence form and concentration of lead oxide (PbO) on the conductivity and viscosity of choline chloride (ChCl)-urea deep eutectic solvent (DES) were investigated. The ESI-MS and FT-IR analyses indicated that three-coordinated complexes are presented in the form of {[PbO·CO(NH2)2]·Cl-}-. It is deduced that the complex anions are formed through sp3hybrid orbitals of Pb2 +ion and three sp hybrid orbitals are all filled with lone pair electrons which are donated by Cl-, O2 -and O atoms of urea respectively. The raising of temperature leads to the electrical conductivity increases. With PbO concentration, however, the conductivity increases firstly and then decreases. The viscosity has an opposite change trend compared with the conductivity. These experimental phenomena can be explained by the formation of PbO-containing complexes and oligomers. © 2014 Elsevier B.V.


Bai S.-J.,State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization | Bai S.-J.,Kunming University of Science and Technology | Wen S.-M.,State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization | Wen S.-M.,Kunming University of Science and Technology | And 3 more authors.
Separation Science and Technology (Philadelphia) | Year: 2014

The characteristics of siderite reductive ore and the ultrafine grinding-magnetic flocculation separation (MFS) of this ore were investigated in the present work. The results indicated that the iron phase in the raw ore was predominantly metallic iron with an iron particle size below 30 μm, and the phosphorus compound was apatite. By applying MFS to siderite reductive ore containing 37.14% Fe and 0.52 P, a concentrate assaying 66.37% Fe and 0.19 P with 74.32% recovery was produced. The iron recovery increased by 5.77% compared with the results of the conventional magnetic separation. The high efficiency in phosphorus removal and iron recovery achieved by the MFS process may be attributed to the adequate liberation of iron particles and the increase in magnetic force on the iron mineral fines in the form of flocs in a magnetic field. © Taylor & Francis Group, LLC.


Tang M.,State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization | Tang M.,Kunming University of Science and Technology | Wen S.,State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization | Wen S.,Kunming University of Science and Technology
Physicochemical Problems of Mineral Processing | Year: 2015

Selective flocculation of hematite with starch is a process well-known in practice. However, the separation of hematite from other minerals depends strongly on the methods of starch digestion performed either as heating-digestion or alkali-digestion (different type and dosage of alkali). The purpose of this study is to identify possible influence of the alkali-digested starch on flocculation of ultrafine hematite when the starch was digested at different concentrations of sodium hydroxide at room temperature. Adsorption of starch digested with sodium hydroxide at different concentration on hematite was investigated by abstraction and co-precipitation tests. Turbidities tests, settling rates, flocculation/dispersion measurement and Fourier transform infrared spectroscopic analysis (FTIR) have also been conducted. Based on the results of the above mentioned tests it is suggested that the flocculating power of caustic digested starch towards fine particles may be significantly weakened, while its dispersing ability starts to play a role instead, if the concentration of sodium hydroxide is high enough in starch digestion. When the weight ratio of NaOH /starch is lower than 2, incomplete gelatinization of starch granules may lead to coagulation of fine particles of hematite mostly due to non-selective electrostatic attraction. The weight ratio of NaOH /starch from 2 to 4 helps to flocculate mineral surfaces selectively and efficiently, assuring a complete digestion of starch granules and a small amount of acidic functional products on the starch chain. However, much smaller and homogenous short-chain granules resulting from higher concentration of sodium hydroxide (the weight ratio of NaOH /starch is more than 4) used to digest starch may weaken the flocculating capacity of the caustized starch for hematite and lead to its dispersion.


Liu T.-S.,State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization | Zhang X.-H.,State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization | Qing S.,Kunming University of Science and Technology | Zhang G.-X.,Power Supply Plant of Gansu Rare Earth Company
Guocheng Gongcheng Xuebao/The Chinese Journal of Process Engineering | Year: 2016

The heat transfer calculation model on the sintering process of iron ore with partially substituted biomass was established, the temperature fields of sintering under 7 sintering schemes were simulated with Fluent software, which were conventional sintering, and substituting conventional fuels by 10%, 20% and 30% bamboo char and chestnut shell char. Based on the calculated results, the reliability of this model was verified by the experimental data obtained by conducting 10% substituting scheme in the factory. And the model was evaluated from the perspectives of the highest temperature and cooling rate of material layer. The results indicated that the solid depth of 20% substituting schemes of bamboo char and chestnut shell char under the solid highest temperature of over 1573 K was 0.47 and 0.49 m, respectively. The solid depth under 20% substituting schemes was more than that of the conventional scheme, 10% and 30% substituting scheme, leading to the increase of the blocking amount of consolidation. The solid depth under 30% substituting schemes of bamboo char and chestnut shell char at the cooling rate of below 120 K/min was 0.458 and 0.480 m, respectively, which was more than that of the conventional scheme, and 10% and 20% substituting scheme, and the mechanical strength of sintering ore could be effectively improved. The bio-chars with much higher ignition point were beneficial to maintaining the highest temperature of material layer, while bio-chars with much lower ignition point were beneficial to improving sintering speed. © 2016, Science Press. All right reserved.


Liu S.,State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization | Zhao Y.,Kunming University of Science and Technology | Wang W.,Kunming University of Science and Technology | Wen S.,Kunming University of Science and Technology
Minerals and Metallurgical Processing | Year: 2014

In China, most reserves of rich iron ores have now been depleted and sustainable development of low-grade iron ores has become a critical discussion topic in the mining industry today. The aim of this study was to evaluate the applicability of beneficiating a low-grade, hematite-magnetite ore (assaying 18.64% Fe) for subsequent utilization. In this study, process mineralogy and beneficiation of the ore were carried out in the laboratory. First, mineralogical investigation shows that the main metal minerals are hematite, magnetite and a little octahedrite that cannot be used at present, and the main gangue minerals include albite, quartz and ankerite. Based on the above, a combined process of magnetic separation and gravity concentration has been developed by using laboratory low- and high-intensity magnetic separators and a slimes shaking table, respectively. Factors affecting these separation methods are discussed, including process mineralogy on the tailings of the high-intensity separator, where the iron minerals were found to be finely disseminated in the gangue as inclusions. By applying a two-stage grinding step and a magnetic separation stage together with gravity concentration, a marketable iron concentrate assaying 60.79% Fe at a recovery of 60.23% can be obtained, when the feed assays 18.75%Fe, which provides some useful information for the sustainable use of low-grade iron ore. Copyright 2014, Society for Mining, Metallurgy & Exploration Inc.


Wang W.,Northeastern University China | Wu F.,The Key Laboratory of Metallurgy and Energy Conservation of Guizhou | Wu F.,State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization | Jin H.,The Key Laboratory of Metallurgy and Energy Conservation of Guizhou
Heat and Mass Transfer/Waerme- und Stoffuebertragung | Year: 2016

Since the magnesiothermic reduction employed in current sponge titanium is a highly exothermic reaction, the TiCl4 feed rate is carried out slowly to keep a suitable temperature in reduction reactor, which accounts for an extremely low level of productivity and energy efficiency. In order to shorten the production cycle and improve the energy efficiency, an enhancing scheme is proposed to enhance the heat transfer of air cooling zone for reduction system. The air cooling zone and enhancing scheme are firstly introduced. And then, the heat transfer characteristics of cooling zone are obtained by theoretical analysis and experimental date without enhancing scheme. Finally, the enhancement is analyzed and evaluated. The results show that the fitting results of heat transfer coefficients can be used to evaluate the heat transfer enhancement of cooling zone. Heat sources temperatures have a limited decreasing, heat transfer rate increases obviously with the enhanced cooling, and the TiCl4 feed rate can be increased significantly by 9.61 %. And the measured and calculated results are good enough to meet the design requirements. © 2016 Springer-Verlag Berlin Heidelberg

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