TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Method: The recycling of PEG, comprises separating PEG from the waste mortar by performing centrifugation, filtration and solvent washing, where solvent is water or alcohol e.g. ethanol. The recycling of iron, comprises separating iron from the waste mortar by using magnetic separation or pickling method, where the magnet is permanent magnet or electromagnet, and pickling is carried out by washing with an inorganic acid (except hydrofluoric acid). The recycling silicon carbide and silicon micro-powder, comprises performing hydraulic sorting (based on density difference) on the waste mortar after finishing the PEG and iron separation, washing the sorted liquid to separate PEG, and then utilizing overflow method or swirl method (based on production scale and sedimentation condition) to obtain binary sand of silicon carbide micropowder and silicon micro-powder. The method further comprises: either drying the binary sand composed of silicon carbide micropowder and silicon micropowder and sending it into an air classifier to proceed airflow separation to obtain silicon carbide powder and silicon micro-powder, and sorting the silicon powder and washing with purified water and reagent-grade inorganic acid to obtain high purity silicon micro-powder, then adding the separated silicon powder into a furnace and casting under reducing atmosphere or inert gas atmosphere to obtain ingot silicon material; or drying the binary sand composed of silicon carbide micropowder and silicon micropowder and adding into an electric furnace, performing casting under reducing atmosphere or inert gas atmosphere to obtain metallurgical silicon ingot material and silicon-silicon carbide mixed ingot material; or reacting binary sand composed of silicon carbide micropowder and silicon micropowder with carbon material under microwave or electric heating condition to obtain silicon carbide; or adding ternary sand composed of silicon carbide, silicon, iron into a furnace after separating PEG, and casting the ternary sand under reducing atmosphere to obtain metallurgical industrial ferrosilicon ingot material.