Oily cold rolling mill （CRM） sludge is one of the pollutants emitted by iron and steel plants. Recycling oily CRM sludge can not only reduce pollution but also bring social and environmental benefits. In this study,...Oily cold rolling mill （CRM） sludge is one of the pollutants emitted by iron and steel plants. Recycling oily CRM sludge can not only reduce pollution but also bring social and environmental benefits. In this study, using oily CRM sludge as sources of iron oxide, the strontium ferrite powders were synthesized in multiple steps including vacuum distillation, magnetic separation, oxidizing roasting, and solidstate reaction. The optimal technological conditions of vacuum distillation and oxidizing roasting were studied carefully. To consider the effects of Fe203/ SrCO3 tool ratio, calcination temperature, milling time and calcination time on magnetic properties of prepared strontium ferrite powders, the orthogonal experimental method was adopted. The maximum saturation magneti- zation （62.6 mA-m2.g-1） of the synthesized strontium ferrite powders was achieved at the Fe203/SrCO3 mol ratio of 6, 5 h milling time, 1250 ~C calcination temperature, and 1 h calcination time. Strontium ferrite powders syn- thesis method not only provides a cheap, high quality raw material for the production of strontium ferrite powders, but also effectively prevents the environmental pollution.展开更多
Cathode material LiMn2O4 for lithium ion battery was successfully prepared by low heating solid state coordination method. Mixed precursors were tested by TG-DTA to confirm the temperature of thermal decomposition. Th...Cathode material LiMn2O4 for lithium ion battery was successfully prepared by low heating solid state coordination method. Mixed precursors were tested by TG-DTA to confirm the temperature of thermal decomposition. The products from thermal decomposition, LiMn2O4 powders were characterized by XRD, TEM. The results showed that the samples were composed of nanorods assembled by small nanoparticles. The as-prepared LiMn2O4 was of high purity in a good crystal form with a spinel structure type. The powders had uniform chemical composition. The charge-discharge property of LiMn2O4 was also tested. The first charge and discharge capacities for LiMn2O4 were 125.4 mAh·g-1 and 115.3 mAh·g-1, respectively. The efficiency of charge-discharge could be up to 91.95%. In conclusion, LiMn2O4 with better electrochemical property could be obtained by low heating solid state coordination method.展开更多
以Ta_2O_5、Na CO_3为原料,分别以Na Cl-KCl-NaF和Na Cl-KCl为熔盐介质,合成了Na Ta O_3粉体.借助X射线衍射仪、扫描电子显微镜研究了熔盐种类、热处理温度对合成粉体的物相组成和显微形貌的影响.结果表明:不加熔盐时完全反应生成Na Ta ...以Ta_2O_5、Na CO_3为原料,分别以Na Cl-KCl-NaF和Na Cl-KCl为熔盐介质,合成了Na Ta O_3粉体.借助X射线衍射仪、扫描电子显微镜研究了熔盐种类、热处理温度对合成粉体的物相组成和显微形貌的影响.结果表明:不加熔盐时完全反应生成Na Ta O_3的温度为700℃,1 000℃烧后粉体形貌不规则,且团聚严重.当反应物与熔盐的质量比为1∶1时,以Na Cl-KCl-NaF为熔盐,反应物完全转化为Na Ta O_3的温度为600℃,1 000℃时Na Ta O_3晶体长大发育成长方状,粉体晶粒小于1μm;而以Na Cl-KCl为熔盐时完全转化为Na Ta O_3的温度为700℃,900℃合成了形貌为长方状的Na Ta O_3超细粉体.Na Ta O_3超细粉体的粒度和晶体发育程度对光催化性能影响较大.展开更多
基金supported by the National Key Technology R&D Program (Nos. 2012BAC02B01, 2012BAC12B05, 2011BAE13B07, and 2011BAC10B02)the National High Technology Research and Development Program of China (No. 2012AA063202)+2 种基金the National Natural Science Foundation of China (Nos. 51174247 and 51004011)the Science and Technology Program of Guangdong Province, China (No. 2010A030200003)the Ph.D. Programs Foundation of the Ministry of Education of China (No. 2010000612003)
文摘Oily cold rolling mill （CRM） sludge is one of the pollutants emitted by iron and steel plants. Recycling oily CRM sludge can not only reduce pollution but also bring social and environmental benefits. In this study, using oily CRM sludge as sources of iron oxide, the strontium ferrite powders were synthesized in multiple steps including vacuum distillation, magnetic separation, oxidizing roasting, and solidstate reaction. The optimal technological conditions of vacuum distillation and oxidizing roasting were studied carefully. To consider the effects of Fe203/ SrCO3 tool ratio, calcination temperature, milling time and calcination time on magnetic properties of prepared strontium ferrite powders, the orthogonal experimental method was adopted. The maximum saturation magneti- zation （62.6 mA-m2.g-1） of the synthesized strontium ferrite powders was achieved at the Fe203/SrCO3 mol ratio of 6, 5 h milling time, 1250 ~C calcination temperature, and 1 h calcination time. Strontium ferrite powders syn- thesis method not only provides a cheap, high quality raw material for the production of strontium ferrite powders, but also effectively prevents the environmental pollution.
文摘Cathode material LiMn2O4 for lithium ion battery was successfully prepared by low heating solid state coordination method. Mixed precursors were tested by TG-DTA to confirm the temperature of thermal decomposition. The products from thermal decomposition, LiMn2O4 powders were characterized by XRD, TEM. The results showed that the samples were composed of nanorods assembled by small nanoparticles. The as-prepared LiMn2O4 was of high purity in a good crystal form with a spinel structure type. The powders had uniform chemical composition. The charge-discharge property of LiMn2O4 was also tested. The first charge and discharge capacities for LiMn2O4 were 125.4 mAh·g-1 and 115.3 mAh·g-1, respectively. The efficiency of charge-discharge could be up to 91.95%. In conclusion, LiMn2O4 with better electrochemical property could be obtained by low heating solid state coordination method.
文摘以Ta_2O_5、Na CO_3为原料,分别以Na Cl-KCl-NaF和Na Cl-KCl为熔盐介质,合成了Na Ta O_3粉体.借助X射线衍射仪、扫描电子显微镜研究了熔盐种类、热处理温度对合成粉体的物相组成和显微形貌的影响.结果表明:不加熔盐时完全反应生成Na Ta O_3的温度为700℃,1 000℃烧后粉体形貌不规则,且团聚严重.当反应物与熔盐的质量比为1∶1时,以Na Cl-KCl-NaF为熔盐,反应物完全转化为Na Ta O_3的温度为600℃,1 000℃时Na Ta O_3晶体长大发育成长方状,粉体晶粒小于1μm;而以Na Cl-KCl为熔盐时完全转化为Na Ta O_3的温度为700℃,900℃合成了形貌为长方状的Na Ta O_3超细粉体.Na Ta O_3超细粉体的粒度和晶体发育程度对光催化性能影响较大.
