Influences of suspending agents on the rheological and sedimentation characteristics of cemented paste backfill

Blockage during the pipeline transport of cemented paste backfill (CPB) causes significant economic losses to mining operations. Suspending agent (SA) addition has been proposed as an easily implementable and low-cost method to mitigate the risk of pipeline blockage caused by sedimentation during the transportation of CPB. However, the effects of SAs on the rheological and sedimentation properties of CPB are not yet fully understood. This study investigated the rheological and sedimentation characteristics of CPB with different types of SAs. CPB mixtures were prepared with three types of SAs (hydroxypropyl methylcellulose (HPMC), polyacrylamide (PAM), and xanthan gum (XG)) at concentrations of 1.5, 3.0, and 6.0 g/L. The rheological properties (yield stress and viscosity) and sedimentation characteristics (bleeding and monitored via layered electrical conductivity) were measured over 0-2 h. Additionally, zeta potential and microstructural analyses were conducted. SA addition increased the yield stress and viscosity of CPB. Concurrently, the SAs inhibited bleeding and sedimentation. Furthermore, the SAs appeared to significantly inhibit the sedimentation of cement particles. The findings develop CPB technology utilizing SAs and provide important guidance for ensuring smooth pipeline transportation.