Abstract：In the ammonia-soda process, lime slurry is usually used to react with the solution of ammonium chloride to realize the ammonia recycling. Using carbide slag to instead lime slurry is an environmental benign and economical process. The reaction of carbide slag/ammonium chloride was studied in a batch reactor systematically. The effects of different operation parameters, such as reaction time, mass ratio of NH4Cl/carbide slag, reaction temperature, reaction pressure and water content, on the reaction were investigated. Almost no reaction was observed with the temperature range of 60—70 ℃. When the temperature arrived 75 ℃, violent bubbles were observed and the ammonia yield increased with increasing temperature at the temperature range of 75—90 ℃. With increasing of water content, a peak of ammonium yield was observed at the point of water content 65%. The ammonium yield increased with increasing vacuum degree. The optimal reaction conditions as follows: reaction time 20 min, NH4Cl/carbide slag mass ratio of 1.2, reaction temperature 80 ℃, vacuum degree 0.02 MPa, water content 60%. At these conditions, the yield of ammonium reached 57.7%. Using Carbide slag can get a better result than that of lime slurry in Soda industry with a lower water content 60% compared with 74% and a higher ammonia yield of 57% compared with 17%. Reducing water content and improving ammonia yield are beneficial for the following ammonia recovery process and the crystallization of calcium chloride.
