化学发泡法磷石膏基相变材料制备工艺及性能研究

Preparation and properties of phosphogypsum-based phase change materials by chemical foaming method

以磷石膏为原料,柠檬酸和碳酸钙为发泡剂,硬脂酸钙为稳泡剂,并以粉煤灰为助剂,采用化学发泡法制备多孔磷石膏基体材料,然后以石蜡为相变材料,通过浸渍法制备磷石膏基相变储能材料。考察了碳酸钙、柠檬酸、硬脂酸钙、粉煤灰用量对改性多孔磷石膏基体材料孔隙率和力学性能的影响,借助XRD、SEM、FTIR、DSC、TG表征相变储能材料的结构和性能。结果表明,随着各添加剂用量的增加,磷石膏基体材料的孔隙率逐渐上升,抗压强度逐渐下降。响应面优化工艺实验结果显示,当碳酸钙质量百分含量6.4%、柠檬酸3.2%、硬脂酸钙3.3%以及粉煤灰含量为18%时,磷石膏基体材料孔隙率最大可达到64.53%;FTIR结果表明,基体材料未产生新的衍射峰,改性磷石膏与石蜡之间没有发生化学反应,二者仅是物理混合;DSC结果表明,磷石膏复合相变材料相变温度为58.88℃,相变焓为92.95 J/g。将磷石膏和石蜡复合制备具有储热能力的磷石膏基相变材料可用于建筑节能材料,对磷石膏资源化利用提供了一条新的技术路径。

The porous phosphogypsum matrix material was prepared by chemical foaming method with phosphogypsum as raw material,citric acid and calcium carbonate as foaming agent,calcium stearate as foam stabilizer,and fly ash as auxiliary agent.Using paraffin as phase change material,phosphogypsum-based phase change energy storage materials were prepared by impregnation method.The effects of calcium carbonate,citric acid,calcium stearate,and fly ash on the porosity and mechanical properties of the modified porous phosphogypsum matrix material were investigated.The characterization techniques of XRD,SEM,FTIR,DSC,and TG were used to analyze the structure and performance of phosphogypsum-based phase change energy storage materials.The results show that with the increase of the dosage of each additive,the porosity of the phosphogypsum matrix material increases gradually,and the compressive strength decreases gradually.The response surface optimization process experiment results show that when the mass percentage of calcium carbonate is 6.4%,citric acid is 3.2%,calcium stearate is 3.3%,and the content of fly ash is 18%,the porosity of the prepared phosphogypsum matrix material reaches the largest value of 64.53%.FTIR results show that no new diffraction peaks appear meaning no chemical reaction occurs between the modified phosphogypsum and paraffin and they are only physically mixed;DSC results show that the phase change temperature of the prepared phosphogypsum composite phase change material is 58.88℃,the enthalpy of phase transition is 92.95 J/g.Combining phosphogypsum and paraffin to prepare phosphogypsum-based phase change materials with heat storage capacity can be used as building energy-saving materials,which provides a new technical path for resource utilization of phosphogypsum.