| 摘要: |
| 以磷石膏为原料制备α型高强石膏，通过正交试验考察蒸压温度、蒸压时间、料浆含水量及堆料厚度对α型高强石膏的2h抗折强度及干抗压强度的影响，探讨了磷石膏转化成α型半水石膏的过程.结果表明：在蒸压温度130℃，蒸压时间6h，料浆含水量30%（质量分数），堆料厚度15mm以及013%（质量分数）转晶剂的条件下，可制得强度指标为α30的高强石膏；在蒸压条件下，磷石膏中二水硫酸钙通过溶解析晶的方式转化成α型半水石膏晶核，在没有任何外加剂作用时，晶核最终转化成针状晶体；转晶剂可以减缓晶核在c轴方向上的生长速度，使各个方向的生长速率接近平衡，产物呈六方短柱状，同时转晶剂可以改善产物的结晶度. |
| 关键词: 磷石膏 α型高强石膏 转晶剂 相转化 |
| DOI：103969/j.issn1007 9629201401027 |
| 分类号: |
| 基金项目:贵州省科学技术基金资助项目（黔科合J字（2010）2123） |
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| Preparation of α High Strength Gypsum Using Phosphogypsum andTransformation of Phosphogypsum to α High Strength Gypsum |
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YANG Lin, ZHANG Bing, ZHOU Jie, CAO Jianxin
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School of Chemistry and Chemical Engineering, Guizhou University, Guiyang 550025, China
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| Abstract: |
| α high strength gypsum was prepared using phosphogypsum as raw material. The effects of autoclave temperature, autoclave time, water content in the slurry and thickness on 2h flexural strength and dry compressive strength of α high strength gypsum were investigated by orthogonal test. Transformation process of phosphogypsum to α high strength gypsum was studied. The results show that α30 high strength gypsum can be obtained under the following conditions: autoclave temperature of 130℃, autoclave time of 6h, water content in the slurry of 30%(by mass), thickness of 15mm with addition of crystal modifier of 0.13%. Transformation of phosphogypsum to α high strength gypsum nucleus follows the solution crystallization mechanism through autoclave. Without modifier, the nucleus changes into acicular crystal at last. Under the influence of the modifier, growth rate of the nucleus in the c axis is slowed down, and then growth rate in every direction reaches equilibrium. Thus the nucleus change into hexagonal columnar crystal. At the same time the addition of the modifier can improve crystallinity of the product. |
| Key words: phosphogypsum α high strength gypsum crystal modifier phase transformation |
