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Liu J.,Northeastern University China | Liu J.,State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization | Yu Q.,Northeastern University China | Zuo Z.,Northeastern University China | And 4 more authors.
Applied Thermal Engineering | Year: 2016

Metallurgical slags, discharged at high temperature range, are produced as by-products in metallurgical processes. In order to reuse waste energy in molten metallurgical slags, the dry granulation and waste heat recovery technology is a popular technology, compared to water quenching granulation. In the study, the solid particle diameter and size distributions of metallurgical slags with different viscosity and surface tension by dry granulation were investigated. The results indicated that the length of molten slag ligament in granulation for ferroalloy slag, with high viscosity, was long. And there was small change in mean diameter of solid particles with an increase in rotating speed for metallurgy slag with low viscosity and surface tension. The semi-empirical relations, based on the experimental data, can be applied to calculate mean diameter of solid particles for different kinds of metallurgical slags. For blast furnace slag and ferroalloy slag granulation, the main mass fraction peak was located in the range of 2.44-3.14 mm. For copper slag granulation, the main mass fraction peak moved to the range of small diameter with an increase in rotating speed. © 2016 Elsevier Ltd. All rights reserved. Source


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 Source


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.,Central South University | And 4 more authors.
Electrochimica Acta | Year: 2016

The verification of dissolution-electrodeposition pathway and bulk porosity on the impact of in situ electrochemical reduction of solid PbO in choline chloride-ethylene glycol deep eutectic solvent (ChCl-EG DES) is systematically clarified at cell voltage 2.5 V and 353 K. Cyclic voltammetry of the microelectrode loaded with PbO powders in PbO-ChCl-EG saturated solution exhibits that an additional reduction peak corresponding to the deposition of [PbO·Cl·EG]- is observed. There is no conspicuous difference in morphologies between the products obtained from saturated PbO-ChCl-EG and ChCl-EG DES. The effects of bulk porosity of PbO pellet on the deoxidation process, phase composition and morphologies of products are investigated. When the adding amount of NH4HCO3 and bulk porosity of PbO pellet are about 50% (in weight) and 54.49% (in volume) respectively, the reaction rate of PbO to lead is the fast in the range of present study. Moreover, the direct electro-reduction models of PbO pellet in dense and porous form in ChCl-EG DES are proposed and it emphasizes that the bulk porosity plays an important role because a larger porosity allows a faster diffusion of ions and a higher solubility of PbO into [PbO·C·EG]- which is strongly in favor of the deposition pathway. This method not only forms the scientific base for a scientifically electrolytic extraction of metallic lead but also opens an avenue to the electrochemical fabrication of other metals and alloys from oxide precursors. © 2016 Elsevier Ltd. All rights reserved. Source


Tang M.,State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization | Tang M.,Kunming University | Wen S.,State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization | Wen S.,Kunming University | And 2 more authors.
Mineral Processing and Extractive Metallurgy Review | Year: 2016

Selective flocculation of heating or caustic-digested starch on hematite is well practical. What happens to the starch from alkali-digestion at room temperature or heating-treatment, however, may not be fully understood. An attempt to identifying possible effects of heating- or caustic-digested starch on its adsorption characteristics on fine hematite was made through a series of tests, like adsorption test, micro-flotation test, turbidities test, Fourier transform infrared spectroscopic analysis (FTIR), and Aggregation/dispersion measurement as well. All results from these tests pointed out that those traditional digestion methods have a significant influence on adsorption density of starch on mineral surfaces, as well as its adsorption mechanisms. Since a certain amount of carboxyl groups on the starch remnants resulted from heating- or caustic-digestion probably attributes to the acid/base interaction between the starch and hematite. And much more amounts of carboxyl groups seem to be harvested from the starch digested with sodium/potassium hydroxide at higher concentrations. But the homogeneous and transparent starch gel from alkali-digestion at a concentration of more than 2% at room temperature, consisting of a great many short-chain remnants, may probably weaken its flocculating capacity on hematite and lead to performing a potentially dispersing role instead. It is also worthy to notice that the starch gel from a combination of caustic-digestion at a 1.5 weight ratio of sodium hydroxide to starch and heating-treatment at the temperature of 100°C reached an adsorption density of almost 12 mg/g hematite, compared with 9.0 mg/g from caustic-digested starch at same concentration or 6.2 mg/g from heating-treated starch in boiling water only. © 2016 Taylor & Francis. Source


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. Source

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