不饱和聚酯树脂固化磷石膏强度形成机制及微观特性研究

Study on strength formation mechanism and microscopic properties of solidification of phosphogypsum with unsaturated polyester resin

选用不饱和聚酯树脂(UPR)、过氧化甲乙酮固化剂、异辛酸钴促进剂对磷石膏进行稳定固化。研究不同UPR、固化剂掺量对磷石膏固化体各龄期抗压强度的影响。通过SEM与FTIR分析磷石膏固化体强度形成机制及微观形貌,采用ICP-MS对磷石膏固化体进行浸出毒性分析。结果表明,磷石膏固化体各龄期抗压强度随着UPR掺量增加而增大;随着固化剂掺量的增加,磷石膏固化体抗压强度呈先增后减的趋势;磷石膏固化体抗压强度前期增长较快,后期增长较慢。磷石膏固化体最佳配合比为磷石膏100%、UPR外掺40%、固化剂外掺0.8%、促进剂外掺0.4%,其3,7 d和28 d抗压强度分别为30.8,36.3 MPa和37.2 MPa。UPR填充了磷石膏间的孔隙,紧密包裹住磷石膏并相互黏结,通过固化剂和促进剂引发的共聚反应快速凝固,生成的高分子三维交联网状结构使固化内部结构致密,形成了离子不易被交换的内部结构。磷石膏固化体浸出F^(-)、PO_(4)^(3-)和其他重金属离子浓度均满足GB 8978—1996《污水综合排放标准》中Ⅰ级排放标准要求。

Unsaturated polyester resin,methyl ethyl ketone peroxide curing agent,and cobalt isooctanoate accelerator(accelerator)were selected to stabilise and cure phosphogypsum.The effects of different dosages of UPR and curing agent on the compressive strength of the solidified bodies at various ages were investigated;the strength formation mechanism and microscopic morphology of the phosphogypsum csolidified bodies were analysed by SEM and FTIR;and the leaching toxicity analysis of the phosphogypsum solidified body was carried out by ICP-MS.The study shows that:the compressive strength of phosphogypsum solidified bodies at all ages increases with the increase of UPR doping;with the increase of curing agent doping,the compressive strength of phosphogypsum solidified bodies shows a tendency of increasing firstly and then decreasing later;the compressive strength of phosphogypsum solidified bodies grows faster in the early stage and slower in the later stage.The optimal ratio of phosphogypsum solidified body is 100%phosphogypsum,40%UPR doping,0.8%curing agent doping,0.4%accelerator doping,and its 3,7,28 d compressive strength are 30.8,36.3,37.2 MPa,respectively.UPR fills up the pore space of phosphogypsum,tightly wraps around the phosphogypsum and binds with each other,and it solidifies rapidly through the copolymerization reaction triggered by the curing agent and the activator,and generates the phosphogypsum solidified bodies.Through the copolymerisation reaction triggered by the curing agent and accelerator,it solidified rapidly,and the generated polymer three-dimensional crosslinked mesh structure made the internal structure of the curing dense,forming an internal structure in which the ions could not be exchanged easily.The concentration of F^(-),PO_(4)^(3-) and other heavy metal ions leached from the cured body of phosphogypsum meets the requirements of GB 8978—1996“Comprehensive Sewage Discharge Standard”,Class I discharge standard.