Electric rotary kiln is one of the key equipment in the chemical industry, which is mainly used for heating materials. In the current research, the heat calculation method of the electric rotary alumina kiln is constructed, and the heat transfer processes in the furnace, the furnace tube, and the furnace tube wall are systematically analyzed. The theoretical model of the electric rotary alumina kiln is established and solved by the fourth-order Runge-Kutta method, and the temperature rise curves in the kiln are obtained. The numerical simulation is carried out to investigate the temperature distribution of materials and gases in the furnace tube. It is revealed in the results that the temperature distribution of the electric rotary alumina kiln is more uniform than that of the internal rotary kiln, and the stable operation state can be reached in a very short time, which means that reduced furnace tube length and reduced production cost can be achieved under the same roasting requirements.

Sub-molten salt was applied to the decomposition of zircon sand (ZrSiO4). The kinetics of the decomposition of zircon sand and the effects of reaction temperature, reaction time, NaOH content, agitation speed, and the NaOH/ore mass ratio on the decomposition rate of zircon sand in NaOH sub-molten salt were investigated. The results indicate that the decomposition rate of zircon sand increases with the increase in the reaction temperature, reaction time, and NaOH content. The shrinking-core model with surface chemical reaction-controlled process is the most applicable for the decomposition of zircon sand, with the apparent activation energy of 77.98 kJ/mol. The decomposition product is sodium zirconium silicate (Na2ZrSiO5), and the decomposition rate is higher than 99% under the optimal conditions.

在水热体系中研究了以阳离子表面活性剂为主,阴离子表面活性剂、非离子表面活性剂、中性伯胺等为辅的混合表面活性剂对合成锆掺杂介孔分子筛的影响,考察了水/SiO2摩尔比、晶化温度、晶化时间及混合表面活性剂/SiO2摩尔比对所制分子筛结构的影响,对优化条件下合成的样品进行了表征.结果表明,锆掺杂介孔分子筛的最佳合成体系为阴阳离子表面活性剂混合体系,最佳合成配方为水/SiO2摩尔比58,混合表面活性剂/SiO2摩尔比0.15,100℃下晶化48 h.最佳条件下合成的样品在小角区域有一个明显的衍射峰,表明其具有一定的长程有序性,晶面间距d=9.71 nm,平均孔径为5.55 nm,壁厚4.16 nm,具有三维蠕虫状孔道结构,吸附亚甲基蓝、罗丹明B与甲基橙的混合溶液时,对亚甲基蓝的吸附选择性较好,吸附率达90.24％.

In this study, the Yb1–xCaxFeO3 (0≤x≤0.3) nanocrystalline powders were prepared by sol-gel method. We used the method of quantitative analysis to research the gas-sensitive properties for Yb1–xCaxFeO3 to CO2. Also, we investigated the effects of various factors on gas sensing properties by simple variable method. The doping of Ca could not only decrease the resistance of YbFeO3, but also enhance its sensitivity to CO2. When the Ca content x=0.2, Yb1–xCaxFeO3 showed the best response to CO2. The response Rg/Ra to 5000 ppm CO2 for Yb0.8Ca0.2FeO3 at its optimal temperature of 260 °C with the room temperature humidity of 28%RH was 1.85. The response and recovery time decreased with an increase of the operating temperature for Yb0.8Ca0.2FeO3 sensor to 5000 ppm CO2. Furthermore, with an increase of CO2 concentration from 1000 to 50000 ppm, the response time of Yb0.8Ca0.2FeO3 became shorter, and meanwhile the recovery time was longer. CO2-sensing response for Yb0.8Ca0.2FeO3 increased with the increase of relative humidity. The response for Yb0.8Ca0.2FeO3 in the background of air (with the room temperature humidity of 39%RH) at 260 °C could reach 2.012 to 5000 ppm CO2, which was larger than the corresponding value (1.16) in dry air.