共查询到19条相似文献,搜索用时 109 毫秒
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Dissolution kinetics of K2SO4 crystal in aqueous ethanol solutions was studied on-line with ion selective electrode. The concentration of K2SO4 was calculated from the determined electromotive force in which the activity coefficient of components in the liquid phase was calculated with the Pitzer equation. Dissolution kinetic parameters in the modified statistical rate theory were regressed. The correlation results show that dissolution rate of K2SO4 is slower in aqueous ethanol solutions than that in aqueous solutions. The two most important reasons are as follows:(1) The solubility of K2SO4 in aqueous ethanol solutions is lower than that in aqueous solutions, which causes a decrease of the driving force of mass transfer. (2) The process of surface reaction of K2SO4 became slower due to the addition of ethanol, so that the whole process is mainly dominated by the surface reaction instead of mass transfer. 相似文献
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The single crystal growth rates of potassium sulfate in pure aqueous solution under different conditions were determined by photomicrography in a flow system for crystal growth. The effects of themain controlling factors, such as supersaturation, crystal size, solution velocity and crystal growth temperature, on crystal growth rates of potassium sulfate were discussed in detail by using non-linear regression from the experimental data, and several empirical relationships were given. The results showed that the growth rates of crystals increased with supersaturation, crystal size, solution velocity and temperature. Moreover supersaturation was the most important controlling factor influencing growth rates of crystals, crystal size and solution velocity were the secondary and temperature was the least.Furthermore, It was found that the growth rate of crystals along the [100] crystallographic axis was higher than that along the [001] in the same condition. The effect of every factor on crystal growth rates along the [100] crystallographic axis was stronger than that along the [001]. 相似文献
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本文对食盐晶体溶解的过程,进行了动力学分析,提出了溶解过程的动力学模型;并以实验证实,当用水溶解食盐晶体时,实验结果可与模型吻合得很好。为使此溶解过程更趋合理,文中最后又提出了某些结论与讨论,供有关读者参考。 相似文献
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本文研究了醋酸铵缓冲溶液中(pH=7.4)羟基磷灰石的溶解行为,反应温度分别控制在25℃、37.5℃和50℃。用钙离子选择电极测定溶解过程中的钙离子浓度的变化,溶解过程中的钙离子浓度和反应时问的关系能成功地进行Stumm方程拟合。 相似文献
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乙醇-氨水介质中硫酸钾制备工艺研究 总被引:1,自引:0,他引:1
以氯化钾和磷石膏为原料,采用一步法制备硫酸钾。采用乙醇-氨水为介质,通过正交实验讨论了反应时间、反应温度、乙醇质量分数、氨水质量分数、配料比对产品质量、原料转化率以及产品晶形的影响,得出优化工艺条件为:反应时间60 min、反应温度45℃、乙醇质量分数30%、氨水质量分数20%、配料比(磷石膏与氯化钾质量比)1.29∶1。在该条件下,制得产品硫酸钾的氧化钾质量分数为37.34%,氧化钾的转化率为75.56%,氯离子质量分数为0.86%,水质量分数为1.06%。 相似文献
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Kinetics of the Chemical Dissolution of Vanadium Pentoxide in Acidic Bromide Solutions 总被引:2,自引:0,他引:2
A novel vanadium bromide redox flow battery employing a vanadium bromide electrolyte in both half-cells has been proposed.
Preparation of the electrolyte for this redox cell requires the chemical dissolution of vanadium pentoxide powder in the acidic
bromide supporting electrolyte. In this study, the kinetics of the chemical dissolution process were investigated and a second
order surface controlled reaction is reported with rate equation given by: Rate = 5 × 10−4(l mol−1 s−1)[Br−]2 at 25 °C and an activation energy of 37.2 kJ mol−1. 相似文献
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钛白副产硫酸亚铁制取硫酸钾的工艺研究 总被引:4,自引:0,他引:4
以硫到法钛白厂副产硫酸亚铁和氯化钾为原料,采用两步复分解法制取硫酸钾,实验研究了加水量、蒸发水量、洗水量等对工艺过程的影响。 相似文献
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石膏两步法制硫酸钾中K2SO4结晶工艺条件研究 总被引:2,自引:0,他引:2
运用连续流动法,在MSMPR结晶器中系统研究了石膏两步法制硫酸钾第二阶段中停留时间、结晶温度、进料配比及硫酸铵浓度、添加适量NH3对K2SO4结晶过程的影响,确定了适宜的结晶工艺条件;在此条件下,可得到粗大均匀且产品质量达到农用硫酸钾优等品标准的K2SO4结晶;其结果可为石膏两步法制硫酸钾工业化结晶器的设计与放大提供基础数据。 相似文献
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由硫酸亚铁制取硫酸钾和氧化铁红 总被引:10,自引:0,他引:10
以钛白厂副产硫酸亚铁为原料,加入工业品碳酸氢铵,得到碳酸亚铁结晶和硫酸铵溶液,实验研究各参数对过程的影响,得到了最佳工艺条件;用硫酸铵与氯化钾作用制取硫酸钾和氯化铵,确定了适宜的工艺参数;选择一种有机胺介质,它能降低硫酸钾在溶液中的溶解度,使钾的转化率提高到85%;最后将碳酸亚铁通入空气氧化制取铁红。整个过程原料综合利用好,经济效益好。 相似文献
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研究了大孔阴离子交换树脂对有机二胺吸收剂PA-A中SO42-的吸附相平衡和动力学行为。结果表明,D296型树脂对SO42-具有良好的吸附选择性,333K下的吸附容量可达100.20mg.g-1。Langmuir-Freundlich模型能较好地描述吸附交换行为。吸附过程符合Lagergren一级动力学模型。液膜扩散为吸附速率的主要控制步骤。 相似文献