摘要
利用异氰酸酯含有丰富的-NCO基团,可与水进行反应,同时异氰酸酯中的苯环属于疏水性基团,可为材料提供疏水性能的特点,作为改性剂对磷石膏进行改性,提高磷石膏性能,从而实现磷石膏的资源化利用.通过开展相关实验,分别研究异氰酸酯掺入量对磷石膏试件力学性能、软化系数、磷酸根、氟离子浸出效率的影响.结果表明,当异氰酸酯掺入量为0.8％、用水量为70％,所制得的磷石膏试件指标达到:抗折强度2.5 MPa、抗压强度6.70 MPa、软化系数0.87、浸出液中氟离子浓度4.73 mg/L、磷酸根浓度11.49 mg/L;较未掺入异氰酸酯时:抗折强度提高23.15％、抗压强度提高73.13％、软化系数提高89.13％、浸出液中氟离子浓度降低58.91％、磷酸根浓度降低69.87％.
Abstract
Isocyanate contains rich-NCO group,which can react with water,and the benzene ring in isocyanate belongs to the hydrophobic group,which can provide the material with hydrophobic properties.As a modifier,isocya-nate is used to modify phosphogypsum,so as to improve the performance of phosphogypsum.In this paper,the effect of isocyanate content on the mechanical properties,the softening coefficient,and the leaching efficiency of phosphate radical and fluoride ions of the phosphogypsum specimen were studied.The results showed that when the isocyanate content was 0.8％and the water consumption was 70％,the indexes of the phosphogypsum specimen obtained were as follows:flexural strength 2.5 MPa,compressive strength 6.70 MPa,softening coefficient 0.87,fluoride ion con-centration 4.73 mg/L,phosphate radical concentration 11.49 mg/L.Compared with that without isocyanate,the flexural strength of the modified phosphogypsum specimen increased by 23.15％,the compressive strength increased by 73.13％,the softening coefficient increased by 89.13％,the fluoride ion concentration in the leaching solution decreased by 58.91％,and the phosphate radical concentration decreased by 69.87％.
维普
万方数据