外力场与工艺因素的联合作用对纳米碳酸钙粒度的影响

纳米碳酸钙产品的表面活性化 ,粒径的微细化、均匀化是纳米碳酸钙行业的主要发展方向。本文对比加与不加外力场时的电导率—时间曲线和pH值—时间曲线 ,揭示了外力场的作用是提高Ca2 + 的过饱和度 ,诱导碳酸钙迅速成核 ,同时也强化了传质作用 ;并研究了外力场协同作用下 ,碳化初始温度、Ca(OH) 2 乳液质量分数、CO2 流量等工艺因素对产品粒度的影响。实验结果表明 :外力场作用下 ,碳化的最高初始温度可以提高 5℃ ,整个反应过程在室温下进行仍能得到纳米颗粒 ;Ca(OH) 2 乳液质量分数在 9%～ 12 % ,外力场的作用较显著 ,能使产品粒度降低 12～ 15nm ;每克Ca(OH) 2 的CO2 流量为 0 .96L/h时 ,CO2 的吸收和消耗几乎达到平衡 ,外力场作用能使产品粒度减小 10nm左右。

EFFECT OF OUTER FORCE FIELD AND TECHNOLOGICAL FACTORS ON PARTICLE SIZE OF NANO CaCO3

The main development trend of Nano CaCO_3 industry is to prepare the surface-active, size-microminiaturized and -homogenized Nano CaCO_3 products. Time-electro-conductivity and time-pH curves with or without a field of outer force(FOF) are compared in this paper. The results show that FOF can increase super saturation of Ca~ 2+ and induce calcium carbonate to nucleate quickly and also improve solute transfer. And the effects of technological factors such as initial carbonation temperature, the Ca(OH) 2 suspension mass fraction and the flow rate of CO 2 on partical size of calcium carbonate product are studied with a FOF synergy. The test results show that, with the FOF, the top carbonation temperature is increase by 5℃. Yet, the nanoparticles of calcium carbonate can be obtained when whole reaction process is at room temperature. The Ca(OH)_2 suspension mass fraction is 9%～12%, the FOF has very prominent effect and can make product size reduced by 12～15nm. With CO_2 flow of 0.96L/h for one gram of Ca(OH) 2, a near balance between absorption and consumption of CO_2 can be achieved and FOF can make the product size reduced by about 10nm.