A contribution to understanding the rheological measurement, yielding mechanism and structural evolution of fresh cemented paste backfill

Study on the Long-Term Durability and Leaching Characteristics of Low-Consumption Cement Backfill under Different Environmental Conditions

“…The three kinds of cement-sand ratio test cube (1:10, 1:15, 1:20) were placed in the soaking solution with different pH values (4,6,7,8,10), and an appropriate amount of solution samples were taken at the specified soaking time (10 d, 20 d, 30 d, 60 d, 90 d, 120…”

“…The three kinds of cement-sand ratio test cube (1:10, 1:15, 1:20) were placed in the soaking solution with different pH values (4,6,7,8,10), and an appropriate amount of solution samples were taken at the specified soaking time (10 d, 20 d, 30 d, 60 d, 90 d, 120 d) and then filtered with the 0.45 µm membrane filter and stored in a centrifuge tube with a volume of 10 mL. In total, 1% nitric acid was added to the filtrate, and leaching values of four heavy metal ions were obtained by Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES).…”

“…Therefore, Zn is easy to leach under acidic conditions, and the leaching amount changes, obviously. In the alkaline environment, zinc hydroxide exists in the form of Zn(OH) 4 2− and Zn(OH) 5 3− , which can further react with Ca 2+ to form a Ca-Zn hydrate precipitate Ca[Zn(OH) 3H 2 O] 2 , which greatly reduces the amount of Zn 2+ , as shown in Figure 12. When Zn 2+ and OH − react during cement hydration, an amorphous layer of Zn(OH)2 is formed in the solution, which is adsorbed on the surface of hydration products by chemical adsorption [46,47].…”

“…However, longterm immersion of cemented tailings backfill (CTB) in groundwater environments can easily lead to heavy metal leakage and structural damage, posing potential hazards to the ecological environment and mine safety. Solving this problem has become a major challenge for current backfilling technology [4][5][6].…”

Research on Slurry Flowability and Mechanical Properties of Cemented Paste Backfill: Effects of Cement-to-Tailings Mass Ratio and Mass Concentration

“…The total tailings paste slurry possesses a relatively large plastic viscosity, yield stress, and pipeline transportation resistance, normally adopted by pumping transportation [24][25][26]. However, as mining depths continue to increase, the advantages of self-flow transportation aided by gravitational systems are becoming increasingly significant [27,28]. Currently, the stowing gradient of total tailings paste is mainly investigated by implementing an indoor rheometer test, L-tube self-flow test, and semi-industrial loop test [29][30][31][32].…”