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Thermodynamics and kinetics of alumina extraction from fly ash using an ammonium hydrogen sulfate roasting method

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International Journal of Minerals,Metallurgy and Materials 2014年第2期21卷 144-149页

作者： Ruo-chao Wang Yu-chun Zhai zhi-qiang ning School of Materials and Metallurgy Northeastern University

A novel method was developed for extracting alumina （Al2O3） from fly ash using an ammonium hydrogen sulfate （NH4HSO4） roasting process, and the thermodynamics and kinetics of this method were investigated. The thermodynamic results were verified experi-mentally. Thermodynamic calculations show that mullite present in the fly ash can react with NH4HSO4 in the 298-723 K range. Process op-timization reveals that the extraction rate can reach up to 90.95% when the fly ash reacts with NH4HSO4 at a 1：8 mole ratio of Al2O3/NH4HSO4 at 673 K for 60 min. Kinetic analysis indicates that the NH4HSO4 roasting process follows the shrinking unreacted core model, and inner diffusion through the product layer is the rate-controlling step. The activation energy is calculated to be 16.627 kJ/mol;and the kinetic equation can be expressed as 1-（2/3）α-（1-α）2/3=0.0374t exp[-16627/（RT）], whereαis the extraction rate and t is the roasting temperature.

关键词： ammonium hydrogen sulfate ore roasting fly ash alumina thermodynamics kinetics

Liver resection for benign hepatic lesions:A retrospective analysis of 827 consecutive cases

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World Journal of Gastroenterology 2008年第47期14卷 7247-7251页

作者： zhi-qiang Feng zhi-qiang Huang Li-ning Xu Rong Liu Ai-Qun Zhang xiao-qiang Huang Wen-zhi Zhang Jia-Hong Dong Department of Hepatobiliary Surgery GeneralHospital ofPLA Beijing 100853 China

AIM:To analyze the operative and perioperative factors associated with hepatectomy of benign hepatic ***:A total of 827 condecutive cases of benign hepatic lesion undergoing hepatectomy from January 1986 to December 2005 in the Chinese PLA General Hospital were investigated retrospectively according to their medical ***:The effect of operative and perioperative factors on the outcome of patients were *** the 827 cases undergoing hepatectomy for more than 3 liver segments accounted for 22.1%,316(38.21%) required transfusion of blood products during *** average operating time was 220.59 ± 109.13 min,the average hospital stay after operation was 13.55 ± 9.38 ***-Pugh A accounted for 98.13%.The postoperative complication rate was 13.54% and the in-hospital mortality rate was 0.24%.Multivariate analysis showed that operating time(P = 0.004,OR = 1.003) and albumin value(P = 0.040,OR = 0.938) were the independent predictors of morbidity and indicated that operating time,blood transfusion,complication rate,and LOS had a trend to ***:Hepatectomy for benign hepatic lesions can be performed safely with a low morbidity and mortality,provided that it is carried out with optimized perioperative management and an innovative surgical technique.

关键词： Hepatectomy Benign hepatic lesion Perioperative

Recovery of silica from sodium silicate solution of calcined boron mud

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Rare Metals 2016年第2期35卷 204-210页

作者： zhi-qiang ning Yu-Chun Zhai Hong-Wei Xie Qiu-Shi Song Ka Yu School of Materials and Metallurgy Northeastern University

The effect of several parameters on the recovery of silicon dioxide from calcined boron mud（CBM）such as stirring speed, temperature, sodium silicate concentration, and carbonation time was studied. The recovery of silicon dioxide is 88 % when the stirring speed is450 r min-1, temperature is 60 °C, sodium silicate concentration is 1 mol L-1, and the carbonation time is 6 *** effect of carbonation time on the recovery of silicon dioxide is divided into three kinetic regimes, and the carbonation process of sodium silicate solution follows a second-order reaction based on the double-film theory model. The apparent rate constant of the three kinetic regimes is 0.064, 3.178, and 1.130 L h mol-1, *** amorphous SiO_2 products obtained by carbonating the purified solution have 99.6 % purity and are spherical with diameters of about 100 nm.

关键词： Boron mud Carbonation Recovery Silicon dioxide

Nickel leaching from low-grade nickel matte using aqueous ferric chloride solution

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Rare Metals 2019年第12期38卷 1199-1206页

作者： zhi-qiang ning Hong-Wei Xie Qiu-Shi Song Hua-Yi Yin Yu-Chun Zhai School of Metallurgy Northeastern University

Nickel leaching from low-grade nickel matte(LGNM) using aqueous ferric chloride solution was *** influence of factors such as leaching temperature and concentration of ferric chloride on the nickel leaching ratio was *** results show that increasing leaching temperature and concentration of ferric chloride increases the nickel leaching *** overall nickel leaching process follows the unreacted shrinking core model,and the surface chemical reaction is the rate-controlling *** activation energy and the reaction order of the nickel leaching process,controlled by the surface chemical reaction,were calculated to be 52.96 kJ mol^(-1)and 0.5,***,the kinetics equation for the nickel leaching was found to be 1-(1-α)^(1/3)=7.18×10~4C^(0.5)exp[-52,960/(RT)]t.

关键词： Nickel matte Ferric chloride Sulfur Kinetics

Interfacial reactions of chalcopyrite in ammonia–ammonium chloride solution

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Transactions of Nonferrous Metals Society of China 2018年第3期28卷 556-566页

作者： Xiao-ming HUA Yong-fei ZHENG Qian XU Xiong-gang LU Hong-wei CHENG Xing-li ZOU Qiu-shi SONG zhi-qiang ning School of Metallurgy Northeastern UniversityShenyang 110004China State Key Laboratory of Advanced Special Steel Shanghai Key Laboratory of Advanced FerrometallurgySchool of Materials Science and EngineeringShanghai UniversityShanghai 200072China

The interfacial reactions of chalcopyrite in ammonia–ammonium chloride solution were *** chalcopyrite surface was examined by scanning electron microscopy and X-ray photoelectron spectroscopy(XPS)*** was found that interfacial passivation layers of chalcopyrite were formed from an iron oxide layer on top of a copper sulfide layer overlaying the bulk chalcopyrite,whereas CuFe1-xS2 or copper sulfides were formed via the preferential dissolution of *** copper sulfide layer formed a new passivation layer,whereas the iron oxide layer peeled off spontaneously and partially from the chalcopyrite *** state of the copper sulfide layer was discussed after being deduced from the appearance of S2-,S22-,Sn2-,S0 and SO42-.A mechanism for the oxidation and passivation of chalcopyrite under different pH values and redox potentials was ***,a model of the interfacial reaction on the chalcopyrite surface was constructed using a three-step reaction pathway,which demonstrated the formation and transformation of passivation layers under the present experimental conditions.

关键词： chalcopyrite interfacial reaction ammonia passivation layer oxidation mechanisms

Kinetics of SiO_2 leaching from Al_2O_3 extracted slag of fly ash with sodium hydroxide solution

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Transactions of Nonferrous Metals Society of China 2014年第6期24卷 1928-1936页

作者：王若超翟玉春宁志强马培华东北大学材料与冶金学院沈阳110819

Kinetics of SiO2 leaching from Al2O3 extracted slag of fly ash with sodium hydroxide solution was *** effect of leaching temperature,mass ratio of NaOH to SiO2 and stirring speed on SiO2 leaching rate was *** results show that increasing leaching temperature,mass ratio of NaOH to SiO2 and stirring speed increases SiO2 leaching *** SiO2 leaching rate is 95.66%under the optimized *** are two stages for the SiO2 leaching process,and the leaching reaction is very rapid in the first stage but quite slow in the second *** whole leaching process follows the shrinking core model,and the outer diffusion of no product layer is the rate-controlling *** activation energies of the first and second stages are calculated to be8.492 kJ/mol and 8.668 kJ/mol,*** kinetic equations of the first and the second stages were obtained,respectively.

关键词： fly ash leaching kinetics SiO2

Extraction of alumina from fly ash by ammonium hydrogen sulfate roasting technology

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Transactions of Nonferrous Metals Society of China 2014年第5期24卷 1596-1603页

作者：王若超翟玉春吴晓卫宁志强马培华东北大学材料与冶金学院沈阳110819

NH4HSO4 roasting technology was used for preparing Al2O3 from fly ash. First, Al and Fe were extracted from fly ash by NH4HSO4 roasting and deionized water leaching. Then, the Al and Fe in the leached liquid were precipitated by adding NH4HCO3 solution. After the mixed precipitations of Al（OH）3 and Fe（OH）3 were leached by NaOH solution, the NaAl（OH）4 solution was decomposed by carbonation. Finally, the pure Al（OH）3 was calcined to α-Al2O3. The optimal conditions of the whole technology were determined by experiments. The quality ofa-Al2O3 product is up to the technical indicator of YS/T 274-1998 standard.

关键词： fly ash ammonium hydrogen sulfate alumina extraction

Research on High-Availability of Softswitch System

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The Journal of China Universities of Posts and Telecommunications 2006年第2期13卷 50-53页

作者： LOU zhi-qiang LIAO ning Beijing Telestar Telecommunications Technology Institute Beijing University of Posts and Telecommunications Beijing 100876 P.R. China School of Telecommunication Engineering Beijing University of Posts and Telecommunications Beijing 100876 P.R. China

Since softswitch is the kernel of the Next Generation Network （NGN）, it is practically significant to improve the availability of the softswitch system. This paper expatiates upon the methods of realizing the high-availability of softswitch system. It gives the methods from a multi-level viewpoint ： software-level high-availability design, platformlevel high-availability of softswitch kernel components, network-level high-availability. Additonally, it gives certain analysis on obtaining network high-availability.

关键词： softswitch high-availability single-distributor multi-processors cluster multi-level monitor

Study of the Mode of Cost-sharing by Indi-viduals for Higher Education in China

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Journal of China University of Mining and Technology 2006年第1期16卷 86-89页

作者： LI qiang WANG zhi-ning School of Management China University of Mining ＆ Technology Xuzhou Jiangsu 221008 China

In recent years, financial crises of higher education have become universal. The policy of cost-sharing by in- dividuals was tried out in many countries. However, empirical studies have shown that the policy has, to a certain de- gree, negative effects for the poor in accepting higher education costs. This paper points out it is the mismatch between tuition fees and the ability to pay that causes the problem. Using two dimensions of group and time to pay, a mode sys- tem, including seven modes for the individual to share the cost of higher education, was constructed. It is suggested that only three modes of pay-immediately have been carried out in China and they all have same shortcomings. To try new modes and exercise different modes synthetically will be meaningful for solving the questions that exist in the current policy.

关键词： cost for higher education cost-sharing mode