Abstract: A great deal of wastewater containing ammonium and nitrogen will be produced in the production process of magnesium salts by ammonia or carbon-ammonia technologies,which can pollute the environment.Magnesia compounds that acted as decomposition regent reacted with ammonium salts existing in the wastewater to achieve a comprehensive utilization of wastewater.Influences of amounts of magnesia,reaction time,and temperature on the decomposition rate of ammonium salts were investigated.Results indicated that more than 90% of ammonium salts in the wastewater can be decomposed under the optimized conditions,which established a theoretical foundation for wastewater treatment in the process of synthesizing magnesium hydroxide via an ammonic route or basic magnesium carbonate via a carbon-ammonia technology.Moreover,this method also provided conditions for ammonia recovery and recycle.

Key words: magnesia, ammonium salts, decomposition rate