以电石渣为原料生产食品级轻质碳酸钙的绿色新工艺

A new and green process for producing food grade light calcium carbonate from carbide slag

以电石渣为原料生产轻质碳酸钙过程中,首先将电石渣用氯化铵溶液进行浸取反应,制得CaCl2-NH3·H2O溶液;然后用CO2进行碳化反应以制得轻质碳酸钙。由于CaCl2-NH3·H2O体系的碱性明显弱于石灰乳体系,不利于在碳化初期形成大量晶核,不利于生产纳米级轻质碳酸钙,却有利于生产食品级轻质碳酸钙。提出了以电石渣和工业上富余的CO2为原料,生产食品级轻质碳酸钙为主、生产水泥原料为辅的联合生产绿色新工艺,实现了以废制废、变废为资源的循环经济目标,具有良好的环境效益、社会效益和经济效益。

In the process of producing light calcium carbonate from carbide slag,Ca Cl2-NH3·H2 O solution is firstly obtained by leaching carbide slag with ammonium chloride solution,and then carbonation reaction takes place between Ca Cl2-NH3·H2 O solution and CO2 to produce light calcium carbonate.Because the alkalinity of Ca Cl2-NH3·H2 O system is obviously weaker than the lime slurry system,it is not conducive to the formation of a large number of crystal nuclei at the early stage of carbonization,which is not conducive to the production of nanoscale light calcium carbonate,but is beneficial to the production of food grade light calcium carbonate.A new and green process based on calcium carbide slag and CO2,which is used as raw materials for the production of light calcium carbonate in food grade,is developed,which also produces cement raw material as by-product.It can realize the recycling economy target with wastes as resources and has good environmental,social and economic benefits.