制配水玻璃自硬砂时,一般仅配以新石英砂,人们曾偿试过在新砂中混入一定数量的再生砂,但其结果不能令人满意。几年前,曾做过混合含有新硅砂和水玻璃自硬砂的再生砂的试验,各国根据所使用的再生方法的不同,加入混合物中再生砂的数量各不相同。通常推荐 Preparation of water-glass self-hardening sand, usually only with new quartz sand, people have tried in the new sand mixed with a certain amount of recycled sand, but the results are unsatisfactory. Several years ago, tests were conducted on a mixture of recycled sand containing fresh silica sand and water glass self-hardening sand. Depending on the method of recycling used, the amount of recycled sand added to the mixture differed from country to country. Usually recommended