水玻璃旧砂中的Na_2O

水玻璃砂铸型因受不同温度的作用，其断面浇注后变成７种不同的颜色．通过对７种不同色层旧砂的再生处理、化学分析和电性能测试，揭示了水玻璃砂型中的Ｎａ２Ｏ经高温浇注后的行为、在旧砂中的分布及其对水玻璃砂再生和再生砂性能的影响

Na 2O in Used Waterglass Sand

The behavior, distribution and effect of Na 2O in used waterglass sand moulds after their pouring at high temperatures on the reclamation of the used sand and the properties of the reclaimed sand are studied on the basis of the reclamation, the chemical analysis and electrical tests of the used sand from 7 different color layers in the section of mould formed under the action of different temperatures. The penetration of Na 2O in silicate sand and its transference in mould are verified by the chemical analysis of sand particles. A hypothesis of four layers, i.e., the film removable, adhesive, penetrative and primary layers, is proposed based on the results of study. The resolvation of residual waterglass, which improves the strength of the reclaimed sand at normal temperatures, is proved to exist by an electrical test.