七○砂作为一种新的造型材料在铸钢生产中已经使用了几年了。目前的情况是:铸件落砂后,没有分解的七○砂大块因不易破碎只好扔掉,而将已经分解为白灰层、过渡层的碎末,加上适量的水和陶土作为背砂使用。在长期反复使用中,背砂的粉尘含量急骤增加,透气性不断下降,废品率大幅度升高。再加上大量不易破碎的砂块被扔掉,背砂不够用,不得不在背砂中加入大量的新砂,这就带来了经济上的损失,迫使人们研究七○砂的再生问题。 Seven sand as a new modeling materials in the production of steel has been used for several years. The current situation is: Casting sand, no decomposition of the seventy sand big chunks had to throw away because it is not easy to break, and will have been decomposed into lime layer, the transition layer of ground powder, add the appropriate amount of water and clay as the back sand use . In the long-term repeated use, the back of the sand dust content increased sharply, the permeability decreased, the rejection rate increased significantly. Coupled with a large number of unbreakable sand was thrown away, the back is not enough, had to add a large amount of sand in the back sand, which brings economic losses, forcing people to study the problem of the regeneration of 70 sand.