| 摘要: |
| 采用流态化对磷石膏进行热处理，通过确定流态化控制参数，测定样品中可溶性磷、氟、有机物、石膏相组成以及胶凝性能，并采用比表面积及空隙分析仪(BET)和扫描电镜(SEM)对样品比表面积、微观形貌进行分析.结果表明：当控制气体流速35m/s、停留时间30s时，能实现持续稳定的流态化.随着流态化温度的升高，样品中可溶磷、氟、有机物杂质的含量逐渐降低，pH值增加.在流态化热处理过程中，磷石膏中的CaSO4·2H2O向CaSO4·05H2O，Ⅲ CaSO4及Ⅱ CaSO4转变，形成复相石膏体系；当流态化温度低于400℃时，半水石膏相含量随温度的升高而增加，超过400℃时，无水石膏相含量随温度的升高而增加.在流态化热处理过程中，磷石膏通过表面脱水方式形成半水或无水石膏相，并在其表面形成大量的裂纹；由于颗粒之间相互碰撞及晶粒细小化，石膏粉的比表面积逐渐增大.当控制流态化温度400℃、停留时间30s时，所制石膏粉2h抗折强度为21MPa，2h抗压强度为43MPa. |
| 关键词: 流态化 磷石膏 热处理 杂质 性能 |
| DOI：103969/j.issn.1007 9629201903011 |
| 分类号: |
| 基金项目:教育部“春晖计划”项目(Z2006 1 52004)；贵州省科技计划项目(黔科合支撑[2018]2194) |
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| Effect of Fluidized Heat Treatment on Impurities and Gelling Properties of Phosphogypsum |
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JIAO Yehong1, YANG Lin1, LI Hejun2, LIU Li3, CAO Jianxin1
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1.School of Chemistry and Chemical Engineering, Guizhou University, Guiyang 550025, China;2.Guizhou Building Material Quality Supervision Testing Center, Guiyang 550000, China;3.College of Pharmacy, Guizhou University, Guiyang 550025, China
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| Abstract: |
| Soluble phosphorus, fluorine, organic matter, gypsum phase composition and gelling properties of phosphogypsum which was fluidized heat treatment by controlling the parameters were determined, and specific surface area and the microcosmic morphology of the sample also were analyzed by using the BET and SEM. The results show that the fluidization process is continuous and stable by controlling the parameters of the gas flow velocity 35m/s and the stay time 30s. With the increase of fluidization temperatures, the content of soluble phosphorus, fluorine and organic impurities in the sample decrease gradually and then pH value increases. In the fluidized heat treatment process, phosphogypsum forms complex phases undergoing transformation of CaSO4·2H2O to CaSO4·05H2O, Ⅲ CaSO4 and Ⅱ CaSO4 Under the fluidization temperature less than 400℃, the hemihydrate gypsum phase increases with the rise of temperatures. However, anhydrite phase increases with the rise of temperatures at the fluidization temperature over 400℃. During the fluidized heat treatment process, phosphogypsum forms hemihydrate gypsum or anhydrite phase through surface dehydration, and a large number of cracks are formed on its surface. The specific surface area of gypsum powders increase gradually, because the particles collided with each other and the crystal grains became smaller. Under the control of fluidization temperature 400℃, and time 30s, the mechanical strength of gypsum powders are as follows, the flexural strength 21MPa, the compressive strength 43MPa in the hydration period of 2h. |
| Key words: fluidization phosphogypsum heat treatment impurity property |
