白云灰乳碳酸化工艺研究

中国白云石蕴藏量巨大，白云灰乳碳酸化是白云石碳化法制备轻质碳酸镁、氧化镁等镁化合物的关键步骤之一，关系到镁的产率、产品中钙的含量及生产成本。通过单因素实验和正交实验，研究了碳酸化过程镁的溶出率及重镁水中的钙含量与碳酸化反应温度、反应终点pH、白云灰乳质量浓度的关系，从而为提高碳酸化过程镁的溶出率，实现钙镁的有效分离提供可靠的依据。研究表明：影响镁的溶出率及重镁水中钙含量的主要因素为pH。白云灰乳碳酸化最佳工艺条件：白云灰乳质量浓度为9.00 g/L（以氧化镁计），反应温度为30 ℃，反应终点pH为7.50。在此条件下镁的溶出率为74.49%，重镁水中钙的质量浓度为0.10 g/L。

Study on carbonation technology of calcined dolomite slurry

The dolomite deposit is huge in China.The carbonation of calcined dolomite slurry is one of the key steps in the production of magnesium compounds，such as light magnesium carbonate and magnesia，by carbonating dolomite，because it relates to magnesium dissolution rate，calcium content，and production cost.The relationship among magnesium dissolution rate，calcium content in Mg（OH）₂  solution，reaction temperature，pH at end point，and mass concentration of the calcined dolomite slurry were studied through the single factor and orthogonal test so as to increase the magnesium dissolution rate and to improve the separation efficiency of calcium and magnesium system.The study showed that the main influence factor on magnesium dissolution rate and calcium content in Mg（OH）₂  solution was pH，and the optimal conditions of carbonation of calcined dolomite slurry were decided as follows: the mass concentration of the calcined dolomite slurry was 9.00 g/L（calculated as MgO），the reaction temperature was 30 ℃，and the pH at end point was 7.50.Following the above conditions，the magnesium dissolution rate was 74.49%， and the calcium content in Mg (OH)₂ solution was 0.10 g/L.