Properties of Magnesium Potassium Phosphate Cement Containing Heavy Metal Pb

Abstract:

To study properties of magnesium potassium phosphate cement(MKPC) containing heavy metal Pb, the fluidity, setting time, compressive strength, shrinkage deformation and leachate mass concentration of heavy metal Pb were determined. Its hydration heat, phase composition and micro structure were analyzed. The result indicates that the composite retarder and some Pb(NO3)2 are able to effectively retard setting of MKPC paste. Adding of some Pb(NO3)2 reduces the compressive strength of MKPC paste and slightly increases its shrinkage deformation, but 28d compressive strength of MKPC paste with 10% (by mass) Pb(NO3)2 is higher than 20MPa and its shrinkage deformation is almost one order of magnitude lower than that of Portland cement mortar. Pb leachate mass concentration in MKPC paste gradually increases with increase of Pb(NO3)2 content, Pb leachate mass concentration in MKPC paste with 10%Pb(NO3)2 is much lower than that set forth in the standard of ‘Identification of standard for hazardous wastes’ (GB 50853—2007).