Study on Extraction of Calcium Ions from Calcium Carbide Slag by Ammonium Chloride Leaching
Calcium carbide slag is a waste residue generated after the hydrolysis of calcium carbide in the industrial production of acetylene gas,mainly composed of Ca(OH)2.In order to achieve the purpose of purifying calcium and resource utilization,the article uses ammonium chloride solution as a leaching agent to extract calcium ions from calcium carbide slag.The leaching rate of Ca2+under different water usage,ammonium chloride dosage,reaction temperature and reaction time were investigated through experiments,and a detailed analysis of the leaching solution and filter residue compositions were conducted.The results shows that the Ca2+leaching rate can be reach to the highest at 76.58%,when the reaction temperature is 25 ℃,reaction time is 40 min,and the ratio of carbide slag:Ammonium chloride:water consumption is 5∶6∶35.After leached with ammonium chloride,impurities such as Mg,Al,Fe and C in the carbide slag were removed,and the purity of Ca2+reached to 98%.The main components of the filter slag are carbon powder,calcium carbonate,hydrocalumite and ettringite.