摘要
以水洗磷石膏为原料,采用半液相蒸压法制备α-半水石膏。从脱水反应、晶体形貌、物相组成、强度等角度,研究料浆浓度和pH值对α-半水石膏性能的影响。XRD分析结果表明,料浆浓度在55%~80%和pH值为2.0、4.4、6.7时磷石膏全部转化为半水石膏。结晶水含量、SEM、强度测试结果表明:当料浆浓度从55%增至70%,α-半水石膏生成的诱导期从1 h减至0.5 h,晶体生长期从5 h增至5.5 h,料浆浓度继续增至80%,诱导期从0.5 h增至1.5h,晶体生长期从5.5 h减至4.5 h;发育较好的α-半水石膏晶体形貌均为柱状;当料浆浓度从55%增至65%,长径比从3.0减至2.8,标准稠度用水量从44%降至40%,绝干抗压强度从40 MPa增至43.8 MPa,料浆浓度继续增至80%,长径比从2.4增至3.0,标准稠度用水量从40%增至42%,绝干抗压强度从43.8 MPa降至38.2 MPa,在料浆浓度为65%时,绝干抗压强度最高达到43.8 MPa。pH值从2.0增至6.7,诱导期均为1 h,晶体生长期从3 h增至5 h;发育较好的α-半水石膏晶体形貌均为柱状,长径比从3.2减为2.7后增至2.9,标准稠度用水量从43%降至40%,绝干抗压强度从37 MPa增至43.4 MPa。在料浆浓度为65%,pH值为6.7时,α-半水石膏晶体形貌呈柱状,长径比为2.9,标准稠度用水量为40%,2 h抗折强度为5.9 MPa,绝干抗压强度为43.4 MPa。
hemihydrate gypsum was prepared by half-liquid autoclave method,with water washed phosphogypsum as raw material.The influence of slurry concentration and pH value onα-hemihydrate gypsum was studied by analyzing the dehydration reaction,crystal morphology,phase composition and strength.XRD analysis results show that,phosphogypsum has been completely converted into hemihydrate gypsum at the slurry concentration of 55%to 80%and pH values of 2.0,4.4,6.7.The content of crystalline water,SEM and strength results indicate that when the slurry concentration is increased from 55%to 70%,the induction period ofα-hemihydrate gypsum generation is reduced from 1 h to 0.5 h,and the crystal growth period is increased from 5 h to 5.5 h,the slurry concentration increased to 80%,the induction period is increased from 0.5 h to 1.5 h,and the crystal growth period is reduced from 5.5 h to 4.5 h.The morphology of the bestα-hemihydrate gypsum crystal is columnar.When the slurry concentration is increased from 55%to 65%,the aspect ratio has decreased from 3.0 to 2.8,water requirement of normal consistency,decreased from 44%to 40%,the compressive strength increased from 40 MPa to 43.8 MPa,the slurry concentration increased to 80%,the aspect ratio is increased from 2.4 to 3.0,water requirement of normal consistency has been increased from 40%to 42%,compressive strength decreased from 43.8 MPa to 38.2 MPa,the compressive strength is up to 43.8 MPa at a slurry concentration of 65%.The pH value increased from 2.0 to 6.7,the induction period is 1 h,the crystal growth period increased from 3 h to 5 h,the morphology of the bestα-hemihydrate gypsum crystal is columnar,the aspect ratio decreased from 3.2 to 2.7,and increased to 2.9,the water requirement of normal consistency the decreased from 43%to 40%,and the dry compressive strength increased from 37 MPa to 43.4 MPa.The compressive strength ofα-hemihydrate gypsum can reach 43.4 MPa and 2 h bending strength can reach 5.9 MPa,morphology is columnar,the aspect ratio is 2.9,water requirement of normal consistency is 40%,at slurry concentration of 65%and the pH value of 6.7.
作者
王青
田秀娟
刘冬梅
玉霞
徐港
王斌
WANG Qing;TIAN Xiujuan;LIU Dongmei;YU Xia;XU Gang;WANG Bin(Hubei Key Laboratory of Disaster Prevention and Mitigation,Yichang 443002,China;School of Civil Engineering and Architecture,China Three Gorges University,Yichang 443002,China;Hubei Three Gorges Laboratory,Yichang 443002,China;Hubei Xingfa Chemicals Group Co.,Ltd.,Yichang 443000,China)
出处
《金属矿山》
CAS
北大核心
2022年第12期115-121,共7页
Metal Mine
基金
国家级地方高校能源和环境材料化学学科创新引智基地项目(编号:D20015)
土木工程防灾减灾湖北省引智创新示范基地项目(编号:2021EJD026)
湖北三峡实验室开放/创新基金项目(编号:SC211017,SC211006)。
关键词
磷石膏
Α-半水石膏
料浆浓度
PH值
phosphogypsum
α-hemihydrate gypsum
slurry concentration
pH value
