State Key Laboratory Breeding Base of Complex Nonferrous Metal Resources Cleaning Utilization in Yunnan Province

Kunming, China

State Key Laboratory Breeding Base of Complex Nonferrous Metal Resources Cleaning Utilization in Yunnan Province

Kunming, China
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Wang Z.,Kunming University of Science and Technology | Li J.,Kunming University of Science and Technology | Li J.,State Key Laboratory Breeding Base of Complex Nonferrous Metal Resources Cleaning Utilization in Yunnan Province | Hua Y.,Kunming University of Science and Technology | And 5 more authors.
Xiyou Jinshu/Chinese Journal of Rare Metals | Year: 2016

Molten salt electrolysis is an effective method to prepare refractory metals and their alloys. Fe-Ti oxide electrode containing iron particles was prepared with compression molding of mixture consisting of ilmenite concentration and carbon powder, by carbon thermal reduction in argon atmosphere at 1173, 1273 and 1373 K, respectively, then it was electrochemically reduced to Ti Fe alloy in LiCl-KCl molten salt at 673 K. When the temperatures of carbon thermal reduction were 1173, 1273 and 1373 K, the reduction rates of iron in the electrode were 30.1%, 80.1% and 82.7%, respectively. The conductivities of the electrode were 3.14, 8.06 and 10.87 S·m-1, respectively, and the open porosities were 46.1%, 50.9% and 35.2%, respectively. The reduced iron in the Fe-Ti oxide electrode prepared at 1173 K uniformly distributed and was of small spherical particle, but the reduction rate of iron was low and the electrode strength was inadequate. In the electrode prepared at 1373 K, enrichment, marked segregation, and converging into strips seemed to occur to the reduced iron. This made the open porosity of the electrode decrease significantly, and the electrode like this was not beneficial for molten salt electrolyte diffusing and infiltrating inside the electrode. The iron in the electrode prepared at 1273 K was spherical and had particles size of 2~6 μm, and the phenomenon of uniform distribution and high open porosity could be observed. Ti-Fe alloy could be obtained by the electrolytic reduction in low temperature molten salt of KCl-LiCl at 673 K, besides the current was the maximum. © Editorial Office of Chinese Journal of Rare Metals. All right reserved.


Wang Z.,Kunming University of Science and Technology | Li J.,Kunming University of Science and Technology | Li J.,State Key Laboratory Breeding Base of Complex Nonferrous Metal Resources Cleaning Utilization in Yunnan Province | Hua Y.,Kunming University of Science and Technology | And 4 more authors.
Xiyou Jinshu/Chinese Journal of Rare Metals | Year: 2014

The production technology of titanium was summarized systematically. The production methods of titanium were divided into two categories according to the different process conditions and materials containing titanium. One was thermal reduction process; the other one was molten salt electrolysis process. Thermal reduction process included Kroll process, Hunter process, Armstrong process, EMR process using TiCl4 as raw materials; OS process, PRP process, and MHR process used TiO2 as raw materials; and titanate thermal reduction process used titanate as raw materials, etc. Reducing agent was mainly adopted by the liquid or gaseous state of active metal magnesium, calcium, sodium, and their hydride, etc. Molten salt electrolysis process included TiCl4 molten salt electrolysis process, titanate molten salt electrolysis process and the molten salt electrolysis process using TiO2, TiO·mTiC or titanium slag as raw materials, such as FFC Cambridge process, MER process, USTB process, QIT process, SOM process and ionic liquid electrolysis process, etc. The electrolytes were mainly NaCl, KCl, CaCl2 and their mixtures, etc. Currently, only Kroll and Hunter methods realized industrial production, while other thermal reduction processes were still in the stage of laboratory research and development, because the product could not meet the requirements or they could not achieve continuous production. FFC Cambridge process directly used TiO2 as a raw material for molten salt electrolysis, eliminating the TiCl4 production steps, cutting down the extraction process of titanium and reducing the energy consumption and cost, which was successfully carried out kilogram expanded experiment; the ionic liquid electrolytic process reduced the temperature from hundreds centigrade to near room temperature in molten salt. Because of its low reduction rate and current efficiency, the method should also be further researched. As a result, the molten salt electrolysis method might replace thermal reduction process, and it became a future development direction of preparing titanium and developed from high to low temperature. ©, 2014, Editorial Office of Chinese Journal of Rare Metals. All right reserved.


PubMed | State Key Laboratory Breeding Base of Complex Nonferrous Metal Resources Cleaning Utilization in Yunnan Province
Type: Journal Article | Journal: Journal of nanoscience and nanotechnology | Year: 2012

The process parameters of one step preparation of ZnO/Activated Carbon (AC) composite materials, from vinyl acetate synthesis spent catalyst were optimized using response surface methodology (RSM) and the central composite rotatable design (CCD). Regeneration temperature, time and flow rate of CO2 were the process variables, while the iodine number and the yield were the response variables. All the three process variables were found to significantly influence the yield of the regenerated carbon, while only the regeneration temperature and CO2 flow rate were found to significantly affect the iodine number. The optimized process conditions that maximize the yield and iodine adsorption capacity were identified to be a regeneration temperature of 950 degrees C, time of 120 min and flow rate of CO2 of 600 ml/min, with the corresponding yield and iodine number to be in excess of 50% and 1100 mg/g. The BET surface area of the regenerated composite was estimated to be 1263 m2/g, with micropore to mesopore ratio of 0.75. The pore volume was found to have increased 6 times as compared to the spent catalyst. The composite material (AC/ZnO) with high surface area and pore volume coupled with high yield augur economic feasibility of the process. EDS and XRD spectrum indicate presence of ZnO in the regenerated samples.

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