Study on preparation and microscopic properties of typical sulfate solid waste composite cementitious materials
The environmental pollution and resource waste caused by sulfate industrial solid wastes have attracted wide-spread attention from scholars at home and abroad.At present,two typical sulfate solid wastes in China,electrolytic manga-nese slag and phosphogypsum,have huge stockpiles and cause serious environmental pollution,so it is urgent to realize their harmless and resourceful utilization.Based on the characteristics of two kinds of solid wastes,electrolytic manganese slag and phosphogypsum were used to prepare composite cementitious materials by combining slag with electrolytic manga-nese slag and phosphogypsum,and the effects of different blending amounts of phosphogypsum and ordinary silicate cement on the mechanical properties of the composite cementitious materials were investigated.The physical composition and micro-scopic morphological changes of the hardened body were analyzed by XRD,SEM and EDS,and the toxicity leaching test was also conducted on the hardened body.The results showed that the strength of the hardened body at each age was in-creased with the increase of cement dosing,and the strength of the hardened body at each age was decreased with the in-crease of phosphogypsum dosing.The 28 d compressive strength of the composite cementitious materials with the ratio of 50%electrolytic manganese slag,20%phosphogypsum,30%slag and 12%cement admixture could reach 27.1 MPa,and the hydration products of sulfate solid waste composite cementitious materials were mainly hydrated calcium silicate(C-S-H)gel and calcium alumina(AFt).The concentration of soluble Mn2+,NH4+-N,PO3-4 and heavy metal ions in the leachate of the hardened body maintained to 28 d met the discharge requirements of GB 8978-1996"Comprehensive Wastewater Discharge Standards"after stabilization.
万方数据
维普
