国内中小型铸造车间(厂)一般均采用粘土型(芯)砂,其旧砂由于长期使用,含泥最高,使铸件废品率增高;为改善型砂的性能,必须加入大量新砂、增加了费用;而大量废弃的旧砂又导致了环境污染。因此旧 The domestic small and medium-sized foundry (factory) are generally used clay (core) sand, the old sand due to long-term use, containing the highest mud, the casting reject rate increased; to improve the performance of sand, you must add a lot of new sand, an increase of costs; The large amount of abandoned old sand has caused environmental pollution. So old