Abstract: Chemical compositions，structural characteristics，and desliming technology of the slime-containing potash ores in Mahai Salt Lake of Qinghai were studied.Results showed that main constituent of slime was aluminum silicates，the particle size of slime was mainly in 100~160 μm and most of slimes filled among the crystal particles of salt minerals or existed in micro-film structure.Grade of potassium chloride could be increased to 16%~20% and the content of slime was at 10%~15%（mass fraction） when the grade of potassium chloride was at 8%~12% by using hydroclone-sieving combined technology.Grade of potassium chloride could be increased to 8% and the content of slime was at 10%~15% when its grade was 4%，and then it can be mixed with high grade potash ores to produce potassium chloride in plant.This study can provide a powerful technical support for the utilization of slime-containing potash ores.

Key words: slime-containing potash ores, hydroclone-sieving, desliming