磷石膏铵盐浸取物制备CaCO_3晶型和形貌的影响因素研究

Study on the Preparation Influencing Factor of the Crystal Form and Morphology of CaCO_3 Using Filtrate of Ammonium Salt Leaching Phosphogypsum

以某磷矿副产磷石膏为原料,采用氯化铵溶液浸取,获得硫酸钙溶液,经鼓泡碳化法制备Ca CO3。考察了H2O2浓度、CO2流速、搅拌速度、初始p H值等因素对Ca CO3晶型、形貌以及分散性的影响,采用XRD、SEM等对样品进行了表征。结果表明,不添加H2O2,或初始p H值>9.5时得到的Ca CO3样品为球霰石型和方解石型的混合相;当H2O2浓度为0.25%、CO2流速为0.2 L/min、初始p H为9.0、搅拌速度为650 r/min时,得到分散性均匀的菱面体形方解石型Ca CO3。研究结果对磷石膏的资源化利用和CO2固定具有重要的环境意义。

Calcium carbonate was prepared with calcium sulfate solution by bubbling carbonization.Calcium sulfate solution derived from leaching phosphogypsum in ammonium chloride solution. The effects of H2O2 density,CO2follow rate,stirring rate,initial p H value on the calcium carbonate crystal form,morphology and dispersibility were investigated. The samples were characterized by powder X-ray diffraction and scanning electron microscope. The results show that the samples are mixed phases for vaterite type and calcite type when doesn’t add H2O2 or the initial p H 〉 9. 5. However,the samples are the dispersed rhombic calcite type when H2O2 density is 0. 25%,CO2 follow rate is 0. 2 L / min,starting p H is 9. 0 and stirring rate is 650 r / min. These results have an important environmental protection significance for resource utilization of phosphogypsum and fixation of CO2.