Abstract: Impurities of iron and stainless steel powder etc. in the waste mortar produced in solar silicon cutting were removed and polyethylene glycol（PEG），silicon，and silicon carbide were recovered by liquid-solid separation，acid-dissolve，and alkali-dissolve depuration methods.Results indicated，using water as solvent，with liquid volume to solid mass ratio（mL/g） of 10∶1， stirring time of 10 min at room temperature，PEG in waste mortar could be dissolved and it could be recovered by the following distillation method；the optimal process conditions of removing iron and stainless steel powder with hydrochloric acid were： c（HCl）=3.0 mol/L， temperature was 40 ℃，reaction time was 1 h，and liquid/solid ratio was 10∶1；using acid-dissolve and alkali-dissolve methods to remove silicon，could make the mass fraction of silicon in silicon carbide powder drop to 0.5% below.

Key words: waster mortar, silicon carbide, silicon, polyethylene glycol