利用电石渣制备球形碳酸钙的研究

Spherical Calcium Carbonate Prepared by Calcium Carbide Residue

为有效利用电石制乙炔的副产物电石渣资源,以电石渣为原料用化学沉淀法合成了球形碳酸钙,并利用X射线衍射、扫描电镜等手段研究了溶液的pH值、电石渣的预处理方式、碳化反应温度、Ca2+浓度、CO2流量等对球形碳酸钙合成的影响.结果表明:电石渣可直接与氯化铵反应,当pH>7时,合成的球形碳酸钙的纯度(质量分数)大于97%,白度大于98;合成球形碳酸钙的最佳碳化反应温度为10℃左右,碳化反应温度是影响球形碳酸钙形成的主要因素;在一定的范围内,随着CO2浓度的提高,球形碳酸钙的分散性变好,粒度变小;当反应溶液中Ca2+的浓度适当时(如0.08 mol/L),球形碳酸钙粒径较均匀,分散性好;利用电石渣可以制备出高质量的球形碳酸钙.

In order to get spherical calcium carbonate by calcium carbide residue, the effects of solution pH value, pretreatment of calcium carbide residue, carbonizing temperature, Ca^2＋ concentration and CO2 flow rate on the formation of spherical calcium carbonate were studied using XRD and SEM. The results show that through calcium carbide residue reacting with NH4Cl directly, the purity of the synthesized spherical calcium carbonate is higher than 97% and its whiteness is higher than 98 when pH value of the solution is over 7. The optimum temperature of forming spherical calcium carbonate is about 10℃, and the carbonizing temperature is the primary factor to affect the formation of spherical calcium carbonate. With the CO2 flow rate increasing in a certain range, the dispersity of the spherical calcium carbonate becomes better, and the size of it becomes smaller. When Ca^2＋ concentration is about 0.08 mol/L, the dispersity of the spherical calcium carbonate is good, and its size is uniform.