Utilization of original phosphogypsum as raw material for the preparation of self-leveling mortar

The accumulation of phosphogypsum from fertilizer industries occupies considerable land resources and causes serious environmental problem. This work aims to study the possibility of recycling original phosphogypsum as raw material for the manufacture of self-leveling mortar. Thus an experimental study was carried out to evaluate the fluidity, flexural strength, compressive strength, shrinkage, bond strength and wear resistance of self-leveling mortar prepared with original phosphogypsum, and the role of phosphogypsum in mortar was also investigated by theoretical analysis, XRD, TG-DSC and ESEM. In addition, the cost of self-leveling mortar prepared with original phosphogypsum was also discussed. The results indicate that all the properties of self-leveling mortar can meet the requirements of Chinese standard (JC/T985-2005) even when the content of phosphogypsum comes up to 55%. Phosphogypsum in mortars not only acts as fillers but also takes part in the hydration of cements. This work provides a method for the direct use of phosphogypsum and offers a high performance mortar used in civil engineering. Besides, the cost of this innovative mortar has been reduced dramatically due to the addition of waste material.