XUE J, WANG X Y, WU J,et al.Application of phosphogypsum-based anhydrous calcium sulfate as a polyvinyl chloride （PVC） filler[J].Journal of Henan Polytechnic University(Natural Science) ,2026,45(5):197-204.

doi:10.16186/j.cnki.1673-9787.2024030070

Received:2024/03/26

Revised:2024/05/06

Published:2026-07-24

Application of phosphogypsum-based anhydrous calcium sulfate as a polyvinyl chloride （PVC） filler

Xue Jun1,2, Wang Xunyan1,2, Wu Jing3, Lin Zhigao4, Liu Fangjun1,2, Li Lei1,2, Ma Huijuan5, Jiang Jizhou1,2

1.State Key Laboratory of Green and Efficient Development of Phosphorus Resources， Wuhan Institute of Technology， Wuhan  430205， Hubei， China；2.School of Materials Science and Engineering， Wuhan Institute of Technology， Wuhan  430205， Hubei， China；3.Hubei Geological Experimental and Testing Center， Key Laboratory of Rare Earth， Rare and Scattered Minerals， Ministry of Natural Resources， Wuhan，  430034， Hubei， China；4.Hubei Jinniu Pipe Industry Co.， Ltd， Wuhan，  430050， Hubei， China；5.Hubei Three Gorges Laboratory， Yichang，  443000， Hubei， China

Abstract: Objectives To address the “three phosphorus” problem associated with phosphogypsum and promote the resource utilization of solid waste， the feasibility of using phosphogypsum-based anhydrous calcium sulfate （P-AH） as a PVC filler was investigated.  Methods Heavy calcium carbonate （HCC） was used as a reference filler. PVC composites were prepared using identical formulations. The mechanical properties （impact strength， flexural strength， and flexural modulus）， thermal conductivity， and thermal decomposition behavior were evaluated. The fracture morphology was analyzed by scanning electron microscopy （SEM） to assess the interfacial compatibility and dispersion of fillers. Pilot-scale production tests were further conducted to verify industrial applicability.  Results For PVC/P-AH composites， the impact strength remained relatively stable with increasing filler content， while the flexural strength and flexural modulus increased significantly， and thermal conductivity increases linearly. At a filler loading of 35 phr， the impact strength， flexural strength， flexural modulus， and thermal conductivity were 9.9 MPa， 64.5 MPa， 3，878 MPa， and 0.252 W/（m·K）， respectively. At higher filler loadings， except for flexural modulus， the overall mechanical performance of PVC/HCC composites was inferior to that of PVC/P-AH composites. SEM analysis revealed obvious particle agglomeration in PVC/HCC composites， which led to reduced mechanical performance. Thermogravimetric analysis showed that PVC/P-AH composites required an energy absorption of 157.13 J/g during thermal decomposition， higher than that of PVC/HCC composites （138.95 J/g）， indicating improved thermal stability. Pilot-scale production of PVC pipes using P-AH produced qualified products. Except for slight color differences， their performance was comparable or slightly superior to that of conventional HCC-filled products.  Conclusions Phosphogypsum-based anhydrous calcium sulfate can be directly used as PVC filler， providing a promising high-value utilization pathway for the application of phosphogypsum.

Key words:phosphogypsum;anhydrous calcium sulfate;filler;polyvinyl chloride （PVC）