which is characterized by being made of the following raw materials in parts by weight: recycled sand 70-90, chromite sand 240-200, coal powder 10-15, sea foam Stone 30-35, bentonite 35-40, rapeseed oil 4-5, alkali-free glass fiber 35-40, copper naphthenate 2-3, boric acid 1-2, furan resin 5-8, nano-kaolin 40-45 , Sodium tripolyphosphate 2-3, benzenesulfonic acid 2-3, water; the present invention uses chromite sand, sepiolite, bentonite, calcined, then high temperature calcined, combined with boric acid, copper naphthenate, etc. Dispersing and grinding, the obtained molding sand has excellent air permeability, cohesiveness, toughness, plasticity, and collapsibility; through the use of glass fiber and boric acid, the strength of the molding sand is increased; the present invention uses organic resin and rapeseed oil as the binder , Strong plasticity, good collapsibility at high temperature. It has chilling characteristics and high production efficiency.