高铝粉煤灰提取氧化铝后硅钙渣用作水泥混合材

Using silicate-calcium slag generated in process of extracting alumina from fly ash as cement admixture

为了使高铝粉煤灰提取氧化铝后所产生的硅钙渣被大量的用作水泥混合材,通过水泥强度、水化放热和干缩性实验研究了原状硅钙渣和脱碱硅钙渣对水泥强度和稳定性的影响。结果表明,当硅钙渣掺量达30%时,硅钙渣水泥强度仍可满足P·C 32.5水泥要求。且随硅钙渣掺入量的增加,水泥早期水化放热速率增加的同时水泥累计水化放热量和干缩率还会显著降低。与原状硅钙渣相比,在同等掺量的情况下,脱碱硅钙渣更有利于保持水泥强度,降低其水化热和改善干缩性。

To massively utilize the silicate-calcium slag,which is generated in process of aluminum extraction from fly ash,as cement mixture,in current study,effects of addition of crude and /or dealkalized silicatecalcium slag on the strength and stability of the cement were analyzed through cement strength assay,hydration heat release assay and dry shrinkage assay. Results showed that even when the amount of added silicate-calcium slag was up to 30%,the strength of the cement still met the criteria of P. C. 32. 5. And as the slag addition increased,the heat release rate during the initial hydration increased,meanwhile the cumulative heat release and dry shrinkage significantly decreased. Compared with the crude silicate-calcium slag at the same addition amount,dealkalized silicate-calcium slag is more beneficial to maintaining the cement strength,lowering the hydration heat release and reducing the dry shrinkage.