Study on the Effect of Nanocellulose Type and Dosage on the Stability Performance of Cemented Backfill with Lithium...

The large-scale accumulation of lithium-feldspar tailings generated during lithium ore beneficiation poses environmental and resource-utilization challenges. Cemented lithium-feldspar tailings backfill (CLFTB) provides an effective approach for their underground disposal and resource utilization; however, its mechanical performance remains a key concern. Nanocellulose, with its high specific surface area and fibrillar structure, has potential for improving the stability and mechanical properties of cementitious tailings backfill. This study investigates the effects of nanocellulose type and dosage on the macro- and micro-scale performance of CLFTB. Three nanocellulose types, namely carboxylated cellulose nanofibrils (CNFs), cellulose nanocrystals (CNCs), and microfibrillated cellulose (MFC), were incorporated at dosages of 0.6-1.5 kg/m³. Uniaxial compressive-strength tests and microstructural analyses were conducted to evaluate their effects. The results showed that all nanocellulose-modified groups exhibited higher compressive strength than the control group. The optimum dosage was 0.9 kg/m³, while MFC provided the greatest strength enhancement among the three nanocellulose types. Nanocellulose incorporation also altered the failure behavior and mitigated crack propagation. EDS analysis further revealed differences in the local elemental characteristics of the modified specimens. Overall, the results demonstrate that nanocellulose, particularly MFC, can effectively enhance the mechanical performance and stability of CLFTB.