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Thermodynamics calculation on the oxidation and sulfur removal abilities of slag in EAF dust pellet reduction process

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Journal of central south university of Technology 2001年第1期8卷 64-68页

作者： PENG Bing 1,PENG Ji 1,ZHANG Chuan fu 1,Jonathan Lobel 2,Janusz A. Kozinski 2 (1 department of metallurgical science and Engineering, {3., changsha 410083, china 2 department of metallurgical Engineering, McGill university 1. department of metallurgical science and Engineering Central South University 410083 Changsha China 2. department of metallurgical Engineering McGill University 3610 University Street H3A 2B2 Montreal QC Canada

The valuable metals in the dust can be recycled by mixing it with reducing agent carbon and lignosulfonate as the binder to make pellets, then returning the pellets to electric arc furnace (EAF) and adding ferro silicon. Part of valuable metals in the dust is reduced by carbon and part of them reduced by ferro silicon for the economical consideration. The reduced metals get into the steel in the stainless steel or special steel production. But the sulfur in the lignosulfonate may affect the quality of produced steel, which is dependent on the status of the smelting slag. The experiments were conducted in the way of changing the ratio of start iron, pellets, ferro silicon and lime. The content of the slag was checked by XRF for the calculation thermodynamics study. The active concentrations of materials in the slag, the slag abilities of oxidation and sulfur removal in EAF dust reduction process were determined by thermodynamics calculation study on CaO MgO FeO Fe 2O 3.SiO 2 S slag at 1 550 ℃. The oxidation ability of slag can be expressed as N (FetO)= N (FeO)+6 N (Fe 2O 3.+8 N (Fe 3. 4). The sulfur removal ability is dependent on the amount of added ferro silicon and the basicity of the slag. The calculation thermodynamics model was set up and it could be applied to the practical production.

关键词： thermodynamics calculation slag electric arc furnace dust

Hydrochloric acid recovery from rare earth chloride solutions by vacuum membrane distillation

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Rare Metals 2006年第3期25卷 287-292页

作者： TANG Jianjun ZHOU Kanggen school of Construction and environmental Engineering Shenzhen Polytechnic Shenzhen 518055 China metallurgical Separation science and Engineering Lab Central South University Changsha 410083 China

The possibility of the recovery of hydrochloric acid from rare earth （RE） chloride solutions was first experimentally studied by batch vacuum membrane distillation （VMD）. The recovery by continuous VMD was also studied to devise methods that enabled the operation of VMD setup in a stable condition as well as to increase the membrane-operating life The results indicated that HCl separation with RE by VMD was possible, and the recovery ratio of 80% could be achieved by batch VMD. In continuous VMD, when the temperature of circular solutions, circular rate, and downstream pressure was 62-63., 5.4 cm/s, and 9.3. kPa, respectively, the HCl concentration in circular solutions and the processing capacity per membrane area were obtained. The mathematical results were in accordance with the experimental ones.

关键词： membrane separation hydrochloric acid recovery vacuum membrane distillation rare earth mathematical stimulation

A Series Piezoelectric Quartz Crystal Response Kinetics for *** Growth in the Presence of Cu(Ⅱ)

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Journal of central south university 2000年第1期12卷 15-19页

作者： CHAI Li yuan 1,2 ,WEI Wan zhi 2,YAO Shou zhuo 2(1. department of metallurgical science and Engineering, {3. of Technology, changsha 410083, china 2. College of Chemistry and Chemical Engineering, Hunan university, changsha 1. department of metallurgical science and Engineering Central South University of Technology 410083 Changsha China 2. College of Chemistry and Chemical Engineering Hunan University 410082 Changsha China

The kinetics on the growth of *** in the presence of Cu(Ⅱ) was studied using of series piezoelectric quartz crystal (SPQC). Arsenic ion inhibits the growth of *** , which is consistent with the previous results by other measuring methods. This further demonstrates that the SPQC can monitor the chemical activity of *** growth. Cupric ion accelerates the growth of *** . The mechanism was discussed, i. e., copper promotes the protein enzyme of *** , rusticyanin, to form over the range of cupric ion concentration studied. The reaction order of cupric ion in accelerating the bacterial growth is 0.067. The growth of *** is dependent on temperature, the apparent reaction activation energy decreases from 25.56 kJ/mol to 18.3. kJ/mol because of the addition of 10 mg/L Cu(Ⅱ) to the bacterial growth solution of pH 2.0 at initial inoculum of 10%.

关键词： series piezoelectric quartz crystal T.ferrooxidans growth kinetics sigmoid curve cupric ion

A new method to improve surface morphology of Ni-Fe-Mo-Co alloy electrode and its catalytic activity for HER

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Rare Metals 2007年第3期26卷 205-212页

作者： LUO Beiping REN Buye XU You ZHENG Yajie department of Chemistry and Chemical Engineering Hunan Institute of Science and Technology Yueyang 414000 China College of metallurgical science and Engineering Central South University Changsha 410083 China Research Institute of Materials science South China University of Technology Guangzhou 510640 China

A new pretreatment method has been developed to improve the catalytic activity of the Ni-Fe-Mo-Co alloy electrode for hydrogen evolution reaction （HER）. The procedure involves pre-electrolyzing the Ni-Fe-Mo-Co alloy electrode in 3.% KOH solution containing 10% potassium sodium tartrate at 70℃ for 2 h, until some of the Mo and Fe elements are leached out. The surface morphology of the Ni-Fe-Mo-Co alloy demonstrates a unique hive-like structure after the pre- treatment, which has the pore size in a nanometer range （about 50 nm）, a very large real surface area, and good stability. The results of the electrochemical studies show that compared to other similar electrode materials and the treated Ni-Fe-Mo-Co electrode by leaching method, the pre-treated Ni-Fe-Mo-Co electrode has a much lower overpotential and much higher exchange current density for HER. In addition, a long-term continuous electrolysis test with a current interruption shows that the Ni-Fe-Mo-Co alloy has excellent catalytic stability.

关键词： catalytic activity surface treatment Ni-Fe-Mo-Co alloy hydrogen evolution electrodeposition

Template Effect on Structure and Morphology of Ni(OH)_2 Powders Prepared by Hydro chemical Method

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Journal of central south university 2000年第1期12卷 20-24页

作者： LIU Zhi hong,LI Qi hou,XU Xiao lin,GUO Xue yi,ZHANG Duo mo (department of metallurgical science and Engineering, {3. of Technology, changsha 410083, china) 1. department of metallurgical science and Engineering Central South University of Technology 410083 Changsha China

The template effect controlling the structure and morphology of ultrafine particles was described. Ni(OH) 2 powders were prepared by NH 3.coordination precipitation method. The effects of SO 2- 4, NO - 3. Cl -, NH 3. pH value on Ni(OH) 2 structure and morphology were investigated experimentally, explained with the theoretical model that the growth units were the polyhedral structure of coordination anions. The results showed that the structure and morphology of Ni(OH) 2 were effectively controlled by the growth units, the dimensions and the linking patterns of the growth units vary with the changes of physical and chemical conditions in the aqueous solution.

关键词： Ni(OH)_2 structural control polyhedral structure of coordination anions growth units

STUDY ON CONCENTRATING SULFURIC ACID SOLUTION BY VACUUM MEMBRANE DISTILLATION

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Journal of central south university 1999年第2期11卷 99-102页

作者： Zhang Guiqing Zhang Qixiu Zhou Kanggen (department of metallurgical science and Engineering, {3. of Technology, changsha 410083, china) department of metallurgical science and Engineering Central South University of Technology Changsha 410083 China

Concentrating sulfuric acid solution by vacuum membrane distillation with flat PEFE membrane is explored. The effects of sulfuric acid concentration, temperature of the feed, the vacuum degree of the vacuum side on the flux of membrane distillation and the separation efficiency of acid are investigated. The results illustrate that the flux of the membrane distillation increases with the rise of feed temperature and the vacuum degree of the vacuum side, but it decreases with the rise of the sulfuric acid concentration of the feed. The separation efficiency of acid is correlated with the flux of membrane distillation; the separation efficiency of the acid can amount to 100% in the process, when operative conditions are properly controlled. It can also been obtained from the experiment that, compared with other methods of membrane distillation, the vacuum membrane distillation can obtain greater distillation flux.

关键词： membrane distillation sulfuric acid vacuum

Synthesis and characterization of Nd doped M-type hexagonal barium ferrite ultrafine powders

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Journal of central south university of Technology 2001年第2期8卷 130-134页

作者： GUO Rui qian, LI Hong gui, SUN Pei mei, LI Yun jiao, ZHAO Zhong wei, LIU Mao sheng (department of metallurgical science and Engineering, {3., changsha 410083, china) 1. department of metallurgical science and Engineering Central South University 410083 Changsha China

The hexagonal BaNd x Fe12?x O19(x=0.1?1.0) fine powders with M-type structure were synthesized by sol-gel auto-combustion high-temperature synthesis method. The structure of powders, gels’ combustion and magnetic properties of powders were respectively studied by means of X-ray diffractometer (XRD), differential thermal analysis-thermogravimetric analysis (DTA-TG) and vibrating sample magnetometer (VSM). The powders before and after combustion and calcination at 450–850 °C with different mole ratio of Nd to Ba (0.1–1.0) were compared in terms of XRD. In addition, the effects of different synthesis conditions on magnetic properties of powders were also discussed. The results show that at pH 7.0 or so, mole ratio of citrate to nitrate (1–3. and calcination temperature of 850 °C for 1 h, M-type BaNd x Fe12?x O19(x=0.1?1.0) fine powders can be obtained, and the coercive force reaches 43.880 A·m?1 at x=1, which is far greater than that of barium permanent ferrite (BaFe12O19).

关键词： sol-gel method rare earth element permanent ferrite citate ultrafine powder

Analysis of the cause of crack in cold rolling of QSn6.5-0.1 strip

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Journal of central south university of Technology 2001年第2期8卷 94-98页

作者： ZHANG Sheng hua 1,QIN Ye xia 1,LOU Hua fen 2,LU Jun pan 2,ZHONG Wei jia 2 (1 department of Materials science and Engineering, central south university, {3. 410083, china 2.Luoyang Copper Processing Company, Luoyang 471000, china) 1. department of Materials science and Engineering Central South University 410083 Changsha China 2. Luoyang Copper Processing Company 471000 Luoyang China

In order to know the cause of cracks in cold rolling of QSn6.5 0.1 copper alloy strip, a lot of experiments and analysis were done. The microstructure changes of QSn6.5 0.1 were investigated by means of metallurgical microscope. The morphology of cracks and surface defects were examined using scanning electron microscope. Macroscopic residual stresses produced in every process during manufacturing in the QSn6.5 0.1 strip were measured by X ray diffraction method and hole drilling method. The results show that the cracks in the QSn6.5 0.1 cold rolling strip were caused due to the derivation of metallurgical defects, such as SnO 2, S, fine looses,the inverse segregation unable to clear up when milling, and the accumulation of all kinds of resi dual stresses. When the accumulation of the residual stress reaches the material′s breaking strength, the cracks will be generated. Several measures to avoid the development of these kinds of cracks were put forward, such as: controlling the casting technology, improving homogenization annealing procedure (680 ℃/7 h) and milling quality(using the second milling when necessary), working out a more reasonable rolling technology to ensure intermediate annealing in time.

关键词： QSn6.5 0.1 cold rolling strip crack metallurgical defect residual stress

ACID RECOVERY FROM WASTE SULFURIC ACID BY DIFFUSION DIALYSIS

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Journal of central south university 1999年第2期11卷 103-106页

作者： Zhang Guiqing Zhang Qixiu Zhou Kanggen (department of metallurgical science and Engineering, {3. of Technology, changsha 410083, china)

In the process of sulfuric acid production from pyrite, there is a lot of waste acid produced in fume washing with dilute acid. Acid recovery from this sort of waste sulfuric acid by diffusion dialysis is studied in the paper. The mass transfer dialysis coefficient of sulfuric acid of the membrane AFX is measured, the effect of the flowrate of the feed and ratio of feed to water is investigated, and the two kinds of membrane (AFX and S203. are compared. The results show that diffusion dialysis process can separate the metal cation from sulfuric acid effectively, but it is difficult to separate non cation impurities as As - and F -. The contrast tests of the two membranes show that the dialysis mass transfer coefficient of the membrane AFX is larger, while capacity of the removing impurities of membrane S203.is somewhat better.

关键词： diffusion dialysis waste sulfuric acid ion exchange membrane