Abstract: In order to reduce magnesium salt scaling on the pipelines and crystallizer tank walls in the process of potassium sulfate production，and to improve the production efficiency，a magnesium removing agent has been screened out in the labo- ratory by the researchers.The magnesium removing agent addition amount，temperature，and time were studied in detail，and it was also applied in practical production，and good results have been achieved.The filtered magnesium ammonium phosphate obtained in the Mg-removing process could be used as a slow-release fertilizer.It not only will not pollute the environment， but also will bring profits to the company.

Key words: scaling, production efficiency, magnesium removing agent, magnesium ammonium phosphate