白云岩酸解法制备轻质氧化镁和碳酸钙实验研究

以河南卢氏县黄跃沟纯质白云岩为原料,利用盐酸进行分解,制得MgCl2-CaCl2溶液。经过通氨气调节pH值除铁、氨化反应、陈化反应以及碳化反应等过程,制备轻质氧化镁和轻质碳酸钙,研究氨化过程中温度和时间对Mg2+沉淀率的影响,以及碳化时间对碳酸钙制品晶型的影响。采用化学分析方法和扫描电镜分析对制品进行表征,结果表明:轻质氧化镁制品颗粒形貌呈片状,粒径为150 nm左右,其性能达到HG/T2573—2006优等品标准;轻质碳酸钙制品颗粒形貌呈球状,粒径为100 nm左右,其性能达到HG/T2567—1994优等品的标准。实验采用的工艺路线具有能耗低、白云石资源利用率高、加工过程符合清洁生产要求等优点,是白云岩资源高效利用的有效途径之一。

Preparation of Light-weight Magnesium Oxide and Calcium Carbonate from Dolomite by Acidification:An Experimental Study

The dolomite powder,sampled from Huangyue valley,Lushi County of Henan Province,was dissolved using hydrochloric acid to obtain the solution of MgCl2 and CaCl2.The iron and aluminium cations in the solution were removed by adjusting its pH to 6-7.The light-weight magnesium oxide and calcium carbonate were prepared using the purified solution by ammonification,aging and carbonization.This study mainly investigates the effect of ammonification temperature(time) and the aging temperature(time) on the ratio of Mg2+ precipitation,and the effect of carbonization time on the crystal form of calcium carbonate.Scanning electron microscope(SEM) and chemical analysis methods were used to characterize the products.The light-weight magnesium oxide obtained is platelet in form with the average particle size of 150 nm,and matches the chemical industry standard HG/T2573—2006.The light-weight calcium carbonate obtained is sphere in form with the average particle size of 100 nm,and matches the chemical industry standard HG/T2567—1994.The presented technique which is characterized by low energy consumption and high utilization ratio,is a potential environmental friendly way for the clean processing of dolomite ores.