Abstract: Witherite was leached by hydrochloric acid，and the experiment of removing silicon was studied in the witherite pickling solution.The influences of different kinds of silicon removing agent and the addition amount，pH，aging time，and temperature etc. on the silicon removing effect were investigated.Results indicated: adding aluminum chloride under the temperature of 50 ℃， m（AlCl3）∶m（SiO2）=1.0，keeping the pH between 7~8，and 30 min aging time the desilication rate could reach above 80%，and the barium loss rate was under 1.4%.The operation could be easily controlled，and the quality of barium salt could be improved and the frequency of cleaning pipelines in the process of crystallization could also be reduced.This operation will play a positive role in the industrial production.

Key words: witherite, aluminum chloride, desilication