Abstract:

In this study，aiming at the problem of hard and difficult grinding of solid waste in bulk industrial smelting and the technical bottleneck of easy agglomeration of dry grinding，the wet grinding process was innovatively used to synergistically activate the cementitious activity of phosphogypsum and ferronickel slag.The wet grinding time was optimized by characterizing the particle size distribution and Zeta potential of the raw materials.On this basis，the phosphogypsum-nickel-iron slag-based cementitious material system was constructed.The hydration products were characterized by X-ray diffractometer，thermal active microcalorimeter，thermogravimetric analyzer and scanning electron microscope.The performance evaluation was carried out，and the hydration kinetic process and product evolution law were proposed.The results indicated that the cementitious materials prepared from phosphogypsum and ferronickel slag exhibited optimal mechanical properties when the wet grinding time was 6 h and the raw material mass ratio was m_{ferronickel slag}：m_{phosphogypsum}∶m_cement=55∶25∶20.Under these conditions，the mortar specimens achieved flexural strengths of 4.8 MPa and compressive strengths of 19.7 MPa at 3 d，and flexural strengths of 8.5 MPa and compressive strengths of 59.9 MPa at 28 d.Mechanistic research revealed that when phosphogypsum was incorporated at 25%，it significantly promoted the leaching out of Ca²⁺，Al³⁺，and Si⁴⁺ ions from the ferronickel slag.It facilitated the co-growth of trisulfoaluminate hydrate（ettringite，AFt） and C-S-H gel.These hydration products interlaced with each other，increasing the compactness of the matrix.This research provided a novel approach and theoretical underpinning for the high-value utilization of bulk industrial solid wastes.

Key words: ferronickel slag, phosphogypsum, wet grinding, binding material, hydration product