硬石膏代替石膏生产道路硅酸盐水泥工艺

Production of road Portland cement using anhydrite in stead of gypsum

探讨了石膏类型对道路硅酸盐水泥强度、凝结时间及水化热的影响,研究结果表明:SO3掺量达一定值后,其掺量的多少对水泥强度、凝结时间的影响已不明显,但从强度来看,以外掺SO3为1.5%左右为较佳。低温煅烧(700℃)所得的硬石膏制得的水泥比高温煅烧(1350℃)所得的硬石膏制得的水泥凝结时间短,强度高。二水石膏和硬石膏合掺能改善道路水泥的各项性能,一定范围内,随SO3掺量的增加,水泥的干缩率变小,耐磨性增强。掺二水石膏的水泥干缩率比掺硬石膏的水泥干缩率小,水化放热量稍低,半衰期减小。

A study was conducted to investigate the impact of gypsum type on the strength,setting time,resistance to grinding and heat output during hydration of road Portland cement.The results show that the evident effect of SO3 on the strength and setting time of road cement has not been observed after the amount of SO3 added reaches a certain value.However,a 1.5% of SO3 is better in terms of strength.The cement’s setting time is shorter and the strength can be improved by adding the anhydrite burned in a lower temperature（700℃） than in a higher temperature（1350℃）.The strength,shrinkage and the resistance to grinding of road cement can be improved by adding the mixture of gypsum and equivalent anhydrite.In a certain range the resistance to shrinkage and grinding can be improved with the increase of added SO3.The shrinkage of road cement with added gypsum is smaller than that with added anhydrite,and also the heat output during hydration is slightly less,and the half-life turns shorter.