白云石制备似立方体状方解石型碳酸钙晶体及其机理研究

以轻烧白云石粉、氯化铵和二氧化碳为原料,在未使用晶型控制剂的情况下,通过蒸氨-沉钙过程制备出了似立方体状碳酸钙。研究了反应温度、溶液中钙离子浓度、通气速率、搅拌速度以及陈化时间对碳酸钙中方解石相含量以及晶体形貌的影响,并探索了沉钙反应的晶型控制机理。结果表明,在反应温度40 ℃、钙离子浓度0.05 mol/L、通碳速率100 mL/min、搅拌速度400 r/min和陈化时间2 h的条件下,制备出形貌规整、粒径分布均匀的似立方体状碳酸钙,平均粒径为5~10 μm。该研究为提升白云石的使用价值、生产高附加价值的碳酸钙产品,以及提高白云石资源的利用率提供理论基础。

Preparation of Near Cube Form Calcite Type Calcium Carbonate Crystal from Dolomite and Its Mechanism

Near cube form calcite was prepared with light calcined dolomite powder, ammonium chloride and carbon dioxide as raw materials by ammonia-precipitation process without using crystal controlling agent. The effects of reaction temperature, calcium ion concentration in solution, aeration rate, agitation rate and aging time on the content of calcium carbonate and morphology of calcite phase in calcium carbonate were investigated, and the crystal type control mechanism of calcium precipitation reaction was studied. The results show that under the conditions of reaction temperature of 40 ℃, calcium concentration of 0.05 mol/L, carbon dioxide passing rate of 100 mL/min, stirring speed of 400 r/min and aging time of 2 h, near cube form calcium carbonate with regular morphology and uniform particle size distribution is prepared, with an average particle size from 5 μm to 10 μm. This study provides a theoretical basis for improving the use value of dolomite, producing calcium carbonate products with high added value and improving the utilization rate of dolomite resources.