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 s...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 h.The 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, respectively.The amorphous SiO_2 products obtained by carbonating the purified solution have 99.6 % purity and are spherical with diameters of about 100 nm.展开更多
利用X′Pert PRO X-射线衍射分析仪、XL-30能谱分析等岩矿测试手段,系统评价了蒙脱石在5%HCl、5%HCl＋0.5%HF、5%HCl＋1.0%HF、0.5%HF、1.0%HF、8%HBF4、5%HCl＋7%HBF4七种常见酸体系中的化学行为,重点分析了酸液中硅、铝元素离子浓度...利用X′Pert PRO X-射线衍射分析仪、XL-30能谱分析等岩矿测试手段,系统评价了蒙脱石在5%HCl、5%HCl＋0.5%HF、5%HCl＋1.0%HF、0.5%HF、1.0%HF、8%HBF4、5%HCl＋7%HBF4七种常见酸体系中的化学行为,重点分析了酸液中硅、铝元素离子浓度、酸蚀量、晶体结构稳定性等参数随时间、酸浓度、酸类型间变化规律。研究指出,土酸、HF、氟硼酸体系与蒙脱石反应均表现出强酸的性质特点,但是氟硼酸体系离子浓度达到最大值迟土酸0.5~1.0h;与晶体结构中的Si/Al重量理论值对比,发现酸对蒙脱石晶体中的铝氧八面体破坏性强于硅氧四面体。7%HBF4和5%HCl＋7%HBF4两体系与蒙脱石反应2h后d（001）晶面破坏,并出现新峰;而相对应的土酸体系中蒙脱石固相反而比较稳定,因此不难判断B-、F-等有利于促使蒙脱石向其它矿物转化。展开更多
利用X'Pert PRO X-射线衍射分析仪和分光光度仪,系统地评价石英在一定温度下与常见酸体系反应的化学行为,重点分析酸液中可溶硅离子浓度变化特征及影响因素。研究表明,石英与HF、土酸反应快速强烈,前2h硅离子浓度波动大,是硅质沉淀...利用X'Pert PRO X-射线衍射分析仪和分光光度仪,系统地评价石英在一定温度下与常见酸体系反应的化学行为,重点分析酸液中可溶硅离子浓度变化特征及影响因素。研究表明,石英与HF、土酸反应快速强烈,前2h硅离子浓度波动大,是硅质沉淀形成的主要时期,与氟硼酸体系反应慢,达最大反应强度需12h。酸蚀后矿物结构无明显变化,可溶硅离子浓度与长石矿物、粘土矿物上述酸化体系中平均浓度相近。通过快速反排残酸,使用低浓度的HF酸进行酸化,采用过量的后置酸液以及在酸化液中加入相应的阻垢剂可预防砂岩酸化时硅质沉淀的产生。展开更多
基金financially supported by the National Natural Science Foundation of China(No.51204037)the Fundamental Research Funds for the Central UniversitiesChina(No.N140204016)
文摘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 h.The 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, respectively.The amorphous SiO_2 products obtained by carbonating the purified solution have 99.6 % purity and are spherical with diameters of about 100 nm.
文摘利用X′Pert PRO X-射线衍射分析仪、XL-30能谱分析等岩矿测试手段,系统评价了蒙脱石在5%HCl、5%HCl＋0.5%HF、5%HCl＋1.0%HF、0.5%HF、1.0%HF、8%HBF4、5%HCl＋7%HBF4七种常见酸体系中的化学行为,重点分析了酸液中硅、铝元素离子浓度、酸蚀量、晶体结构稳定性等参数随时间、酸浓度、酸类型间变化规律。研究指出,土酸、HF、氟硼酸体系与蒙脱石反应均表现出强酸的性质特点,但是氟硼酸体系离子浓度达到最大值迟土酸0.5~1.0h;与晶体结构中的Si/Al重量理论值对比,发现酸对蒙脱石晶体中的铝氧八面体破坏性强于硅氧四面体。7%HBF4和5%HCl＋7%HBF4两体系与蒙脱石反应2h后d（001）晶面破坏,并出现新峰;而相对应的土酸体系中蒙脱石固相反而比较稳定,因此不难判断B-、F-等有利于促使蒙脱石向其它矿物转化。
文摘利用X'Pert PRO X-射线衍射分析仪和分光光度仪,系统地评价石英在一定温度下与常见酸体系反应的化学行为,重点分析酸液中可溶硅离子浓度变化特征及影响因素。研究表明,石英与HF、土酸反应快速强烈,前2h硅离子浓度波动大,是硅质沉淀形成的主要时期,与氟硼酸体系反应慢,达最大反应强度需12h。酸蚀后矿物结构无明显变化,可溶硅离子浓度与长石矿物、粘土矿物上述酸化体系中平均浓度相近。通过快速反排残酸,使用低浓度的HF酸进行酸化,采用过量的后置酸液以及在酸化液中加入相应的阻垢剂可预防砂岩酸化时硅质沉淀的产生。
