NOVELTY - A waste mortar of solar silicon wafer cutting is recycled and reused by treating via solid liquid separation, adding the separated sand into polyethylene glycol mixed solution containing 2-6% cleaning solution, stirring for 60-180 minutes, treating the mortar via solid liquid separation, adding the available separated sand into polyethylene glycol mixed solution containing 5-20% surfactant, stirring for 1-2 hours, modifying the surface for 6-8 hours, adding into a special package bag of wet sand material, and adding the separated sand into a special mortar production system.    USE - Method for recycling and reusing waste mortar of solar silicon wafer cutting (claimed).    ADVANTAGE - The method changes the conventional sand washing technique, is free in sewage discharge, and can satisfy the green and environment-friendly regeneration and production idea. The particle size of the recycled separated sand can be easily controlled. Drying step is not needed. When sieving, the sand grains are not crushed. The yield is high, and the use cost is low.    DETAILED DESCRIPTION - Recycling and reusing waste mortar of solar silicon wafer cutting involve:    (A) treating via solid-liquid separation, removing impurities of liquid and sand for purifying;    (B) weighing the separated sand, adding into polyethylene glycol mixed solution containing 2-6% cleaning solution;    (C) stirring for 60-180 minutes at different stirring speeds according to a program;    (D) treating the mortar via solid liquid separation;    (E) preparing new cleaning solution via the separated liquid;    (F) adding the available separated sand into polyethylene glycol mixed solution containing 5-20% surfactant;    (G) stirring for 1-2 hours;    (H) placing in a special storage tank for modifying the surface for 6-8 hours;    (I) adding into a special package bag of wet sand material and sealing the opening; and    (J) adding the separated sand into a special mortar production system, according to the technical requirement, preparing cutting mortar.