Effect of Calcined Hard Kaolin Dosage on the Strength Development of CPB of Fine Tailings with Sulphide

Abstract EN

This study presents the effect of calcined hard kaolin (CHK) as replacement (15–50 wt.%) to Portland cement (PC) on the strength development of cemented paste backfill (CPB) of fine tailings containing sulphide.

PC is used as binder at 20 wt.% dosage.

The results show that CPB sample containing 30 wt.% CHK replacements produces the desired strength and durability (i.e., 26.1% increase in strength over the curing period between 28 d and 360 d).

CPB without CHK does not produce the desired strength and durability (i.e., 32.8% losses in strength over the curing period between 90 d and 360 d).

The quantity of expansive gypsum of CPB containing 30 wt.% CHK is obviously less than that of CPB without CHK.

The porosity of the fine pore for pore diameter < 0.3 μm is obviously higher in CPB containing 30 wt.% CHK than in CPB without CHK, regardless of curing time.

It can be concluded that CHK can be suitably exploited for CPB of fine tailings with sulphide to improve the strength and stability in short and long terms.