High-strength heat-resistant reclaimed sand, preparation method thereof and application of high-strength heat-resistant reclaimed sand in cold core box process

The invention relates to high-strength heat-resistant reclaimed sand, a preparation method thereof and application of the high-strength heat-resistant reclaimed sand in a cold core box process. The method comprises the following steps: crushing and screening the green mold used sand to obtain coarsely treated used sand; carrying out roasting, wet purification and sand-water separation on the coarsely treated old sand in sequence to obtain dry sand; sequentially grinding and screening the dry sand, adding water glass, and stirring and mixing to obtain modified sand; the modified sand is subjected to rotary curing treatment, and the high-strength heat-resistant reclaimed sand is obtained after rotary curing treatment is completed. According to the method, multiple regeneration is conducted through a hot method, a wet method and a mechanical method, then film coating modification is conducted on the surface of the regenerated sand to obtain the modified regenerated sand which is smooth in surface and excellent i