利用电石渣制备针叶形碳酸钙研究

Study on preparation of needle-like shaped CaCO_(3) from calcium carbide slag

为充分利用生产乙炔气体过程中所产生的电石渣,实现固体废弃物的资源化利用,以电石渣为原料、经NH_(4)Cl溶液浸取、NH_(4)HCO_(3)作为碳化剂制备针叶形碳酸钙。研究了反应温度、滴加方式、氨水和碳化剂与Ca^(2+)物质的量比、滴加速度对碳酸钙晶形的影响。结果表明:在反应温度为80℃、n(NH_(3)·H_(2)O)∶n(HCO_(3)^(-))∶n(Ca^(2+))=2∶2∶1的条件下,向HCO_(3)^(-)溶液中以1 mL/min速度滴加Ca^(2+),反应30 min后制得针叶形碳酸钙,长径比为8.3226、粒径(D_(50))为4.200μm、纯度为97.20%。在不加晶形控制剂的情况下,通过调整工艺参数实现了针叶形碳酸钙的形貌控制,从降低原料成本和减少环境污染方面可对未来以电石渣为原料制备针叶形碳酸钙的工业化应用提供参考。

In order to make full use of the carbide slag generated in the production of acetylene gas and realize the resource utilization of solid waste,the needle-like calcium carbonate was prepared from carbide slag by leaching with ammonia chloride solution and NH_(4)HCO_(3) as carbonizing agent.The effects of reaction temperature,dropping mode,dropping speed,the ratio of ammonia and carbonization-agent and calcium ion on the shape of the calcium carbonate were studied.The results showed that the needle shaped calcium carbonate was prepared when the reaction temperature was 80℃,n(NH_(3)·H_(2)O)∶n(HCO_(3)^(-))∶n(Ca^(2+))=2∶2∶1,calcium ion was added to bicarbonate radical solution at the rate of 1 mL/min,and the reaction time was 30 min.The aspect ratio of the product was 8.3226 and the particle size(D_(50))was 4.200μm.The purity of calcium carbonate was 97.20%.Without crystal shape control agent,needle-like calcium carbonate was achieved by adjusting process parameters,which provided reference for the practical application of preparing needle-like CaCO_(3) from carbide slag in terms of reducing raw material cost and reducing environmental pollution in the future.