The aluminothermic reduction of zinc oxide（ZnO） from alkaline battery anodes using molten Al may be a good option for the elaboration of secondary 7000-series alloys. This process is affected by the initial content ...The aluminothermic reduction of zinc oxide（ZnO） from alkaline battery anodes using molten Al may be a good option for the elaboration of secondary 7000-series alloys. This process is affected by the initial content of Mg within molten Al, which decreases the surface tension of the molten metal and conversely increases the wettability of ZnO particles. The effect of initial Mg concentration on the aluminothermic reduction rate of ZnO was analyzed at the following values： 0.90wt%, 1.20wt%, 4.00t%, 4.25wt%, and 4.40wt%. The ZnO particles were incorporated by mechanical agitation using a graphite paddle inside a bath of molten Al maintained at a constant temperature of 1123 K and at a constant agitation speed of 250 r/min, the treatment time was 240 min and the ZnO particle size was 450？500 mesh. The results show an increase in Zn concentration in the prepared alloys up to 5.43wt% for the highest initial concentration of Mg. The reaction products obtained were characterized by scanning electron microscopy and X-ray diffraction, and the efficiency of the reaction was measured on the basis of the different concentrations of Mg studied.展开更多
以γ-Al2O3为原料,炭黑(C)为还原剂,通过碳热还原氮化(carbothermal reduction and nitridation,CTRN)工艺合成了氮氧化铝(AlON)粉体,并通过气压烧结工艺制备了AlON透明陶瓷.借助X射线衍射分析研究了反应温度、保温时间及碳用量对CTRN...以γ-Al2O3为原料,炭黑(C)为还原剂,通过碳热还原氮化(carbothermal reduction and nitridation,CTRN)工艺合成了氮氧化铝(AlON)粉体,并通过气压烧结工艺制备了AlON透明陶瓷.借助X射线衍射分析研究了反应温度、保温时间及碳用量对CTRN反应产物相组成的影响,借助电子探针研究了AlON透明陶瓷的微观结构.研究结果表明:该反应主要受热力学控制,动力学因素也具有重要作用,反应温度和保温时间对AlON粉体的合成均具有重要影响.在1300℃时,开始发生CTRN反应;随着反应温度的升高,AlN的生成量逐渐增加;在1650℃时,开始形成AlON;在1700℃时,AlON的CTRN合成反应基本完成,产物中除含有极少量的AlN外,其余均为AlON相;进一步提高反应温度至1750℃,产物中残余AlN的量有所减少,但不能完全消除.采用CTRN工艺制备的粉体为原料,经1950℃高温气氛反应6h可制备出AlON透明陶瓷,材料微观结构致密、均匀,平均晶粒尺寸约50μm。展开更多
基金the support provided for the development of this research from Centro de Investigacion y de Estudios Avanzados del Instituto Politecnico NacionalConsejo Nacional de Ciencia y Tecnologia (Project CB 81251)
文摘The aluminothermic reduction of zinc oxide（ZnO） from alkaline battery anodes using molten Al may be a good option for the elaboration of secondary 7000-series alloys. This process is affected by the initial content of Mg within molten Al, which decreases the surface tension of the molten metal and conversely increases the wettability of ZnO particles. The effect of initial Mg concentration on the aluminothermic reduction rate of ZnO was analyzed at the following values： 0.90wt%, 1.20wt%, 4.00t%, 4.25wt%, and 4.40wt%. The ZnO particles were incorporated by mechanical agitation using a graphite paddle inside a bath of molten Al maintained at a constant temperature of 1123 K and at a constant agitation speed of 250 r/min, the treatment time was 240 min and the ZnO particle size was 450？500 mesh. The results show an increase in Zn concentration in the prepared alloys up to 5.43wt% for the highest initial concentration of Mg. The reaction products obtained were characterized by scanning electron microscopy and X-ray diffraction, and the efficiency of the reaction was measured on the basis of the different concentrations of Mg studied.
文摘以γ-Al2O3为原料,炭黑(C)为还原剂,通过碳热还原氮化(carbothermal reduction and nitridation,CTRN)工艺合成了氮氧化铝(AlON)粉体,并通过气压烧结工艺制备了AlON透明陶瓷.借助X射线衍射分析研究了反应温度、保温时间及碳用量对CTRN反应产物相组成的影响,借助电子探针研究了AlON透明陶瓷的微观结构.研究结果表明:该反应主要受热力学控制,动力学因素也具有重要作用,反应温度和保温时间对AlON粉体的合成均具有重要影响.在1300℃时,开始发生CTRN反应;随着反应温度的升高,AlN的生成量逐渐增加;在1650℃时,开始形成AlON;在1700℃时,AlON的CTRN合成反应基本完成,产物中除含有极少量的AlN外,其余均为AlON相;进一步提高反应温度至1750℃,产物中残余AlN的量有所减少,但不能完全消除.采用CTRN工艺制备的粉体为原料,经1950℃高温气氛反应6h可制备出AlON透明陶瓷,材料微观结构致密、均匀,平均晶粒尺寸约50μm。
