磷石膏制备碳酸钙晶须的工艺研究

Studies on preparation technology of calcium carbonate whiskers from phosphogypsum

以磷石膏制备的钙渣为原料,通过HCl浸取、NH3.H2O除杂得到精制的CaCl2溶液。采用碳化法制备文石型CaCO3晶须,研究了结构导向剂浓度、CO2流速、反应温度、搅拌速度等因素对文石型CaCO3产品颗粒形貌和结构的影响,得出了最优工艺参数。钙渣酸溶和CaCl2溶液精制条件为HCl与CaCO3摩尔比2.5,HCl浓度2.5mol/L。碳化过程以MgCl2为晶体导向剂,MgCl2浓度为0.4mol/L,CO2通气速度、搅拌速度和反应温度分别为35mL/min、250r/min、80℃,得到的产品试样为文石型CaCO3晶须。

With calcium slag prepared from phosphogypsum as raw materials,refined CaCl2 solution was obtained by HCl solution leaching and NH3·H2O purification.CaCO3 whiskers of aragonite style were prepared by carbonation process.The effects of the following factors,such as the concentration of crystal structure oriented agent,CO2 flow rate,temperature and agitation rate and others,on particle appearance and structure of CaCO3 whiskers of aragonite style were studied,and the preparation conditions of calcium carbonate whiskers were optimized.The optimal parameters are： the molar ratio of HCl to CaCO3 is 2.5,HCl concentration is 2.5 mol/L,crystal structure oriented agent MgCl2 concentration is 0.4 mol/L,CO2 flow rate is 35 mL/min,agitation rate is 250 r/min,and reaction temperature is 80 ℃.