无水石膏 AⅢ对β半水石膏性能的影响及作用机理
Effects and mechanism of anhydrite AⅢ on the performance ofβ-hemihydrate gypsum
郑绍聪 1余强 1宁平 2马金波 2田林 1郑远利3
作者信息
- 1. 云南冶金集团股份有限公司 技术中心，昆明 650031
- 2. 昆明理工大学 环境科学与工程学院，昆明 655011
- 3. 云南冶金科技 美国 有限公司，昆明 650031
- 折叠
摘要
以磷石膏为原料生产β半水石膏粉，研究了可溶性无水 AⅢ对半水石膏粉的影响，采用常规分析方法、TG-DSC、XRD 和扫描电镜等方法对磷石膏原料，β半水石膏粉和石膏产品进行分析和表征。差热分析结果表明：磷石膏低温脱水出现两个 DSC 吸热峰，峰值仅相差6℃并存在重叠现象，说明脱水反应分两步进行，发生了不同反应，熟石膏粉中存在不同相混合物。半水石膏粉煅烧最佳工艺：焙烧温度在170±5℃内，焙烧时间2 h，熟石膏新粉结晶水含量约3．0％，通过陈化，控制结晶水含量4．8％～5．2％，有利于提高熟石膏粉质量。半水石膏水化热效应结果表明：AⅢ活性高，水化速度快，导致添加减水剂时几乎未见减水增强效果，说明 AⅢ影响熟石膏粉质量。陈化粉添加减水剂能提高石膏制品强度，聚羧酸系 HC 掺量0．7％时，绝干强度达到15．0 MPa，强度提高近64．84％；奈系 FDN 掺量0．7％时，绝干强度达到14．8 MPa，强度提高近62．64％；木质素减水剂掺量0．7％时，绝干强度达到13．9 MPa，强度提高近52．75％。
Abstract
Theβ-hemihydrate gypsum was prepared from phosphogypsum and the effects of the soluble anhydrous AⅢ were investigated.The Conventional analytical methods,TG-DSC,XRD and SEM were used to analyze and characterize the β-hemihydrate gypsum and their products.The thermal analysis results showed that two endothermic peaks in the phosphogypsum dehydration reaction,and those two peaks overlapped partly.The difference between the two peaks was only 6 ℃,which indicated that the dehydration reaction included two steps of different reactions and theβ-hemihydrate gypsum existed as mixed phase structure.The optimal conditions for β-hemihydrate gypsum calcinations were 170 ±5℃ for 2 hours.The content of the crystal water inβ-hemihydrate gypsum was about 3.0%.The properties of the gypsum powder could be improved if the content of the crystal water content changed in range of 4.8~5.2% through aging process.The highly activity and fast hydration rate of AⅢ offset the effect of the water reducing agents during the hydration ofβ-hemihydrate gypsum indication that AⅢaffects the performance ofβ-hemihydrate gypsum.The addition of water reducing agents could improve the strength of gypsum products.When 0.7% HC polycarboxylate was added,the strength ofβ-hemihydrate gypsumcan reached to 15.0 MPa,nearly an increase of 64.84%.When 0.7% superplasticizer-FDN was added,the strength reached to 14.8 MPa,nearly an increase of 62.64%,and when 0.7% lignin was added,the strength increased nearly by 52.75% to 13.9 MPa.
关键词
磷石膏/无水石膏/AⅢ/β-半水石膏/减水剂/机理Key words
phosphogypsum/Anhydrite AⅢ/β-hemihydrate gypsum/water reducing agent/mechanism引用本文复制引用
出版年
2015
NETL
NSTL
万方数据