Preparation and Mechanical Properties of Cemented Uranium Tailing Backfill Based on Alkali‐Activated Slag

Abstract

Backfilling disposal based on cement solidification is one of the ways to solve the environmental and safe problems of uranium tailing surface stacking. Alkali-activated slag, especially sodium silicate activated geopolymer, has become the preferred cementing material for the uranium tailing backfilling system because of its advantages of corrosion resistance and high strength. In this paper, uranium tailings and slag are taken as research objects, and the unconfined compressive strength (UCS) is taken as the main quality index. The preparation method of the cemented uranium tailing backfill based on alkali-activated slag was studied, hereinafter referred to as CUTB. The effects of additive amount, activator amount and activator modulus on the strength of CUTB were investigated. The results show that alkali-activated slag is an effective cementing material for the backfilling system of uranium tailing aggregate. The maximum UCS of 28 d age in the test groups is 16.45 MPa. Quicklime is an important additive for preparing CUTB. When the amount of quicklime is 0%, the early and late strengths of the filling body cannot be measured or at a very low level. At the age of 7 d, the order of each factor is additive amount > activator modulus > activator amount, but at the age of 28 d, the order of each factor is additive amount > activator amount > activator modulus. The test results can provide a basis for choosing cementitious materials for backfilling disposal of uranium tailings.

Effect of the Initial Air Content in Fresh Slurry on the Compressive Strength of Hardened Cemented Paste Backfill

“…is will cause the following effects: (i) e damping force F i damp on the particles is reduced because the particles are exposed to less C-S-H. (ii) e decrease of C-S-H results in the increase of σ n and σ s when particles are under pressure, while the contact interface A ij does not change. erefore, it can be seen from equations ( 6), (7), and (8) that F ij increases. Besides, F i ext can be considered unchanged in the gravity field.…”

“…Filling mining method can discharge all or most of the tailings into the underground stope, which can not only effectively manage the ground pressure of stope, but also relieve the environmental and economic pressure of tailings surface depositing [1][2][3][4][5][6][7]. Under this background, the mechanical properties (i.e., compressive strength, tensile strength, and flexural strength) of cemented paste backfill (CPB) have attracted wide attention.…”

Effect of Natural Zeolite on Pore Structure of Cemented Uranium Tailings Backfill

“…However, it is obviously inappropriate to completely rely on the process of cement solidification disposal of medium and low-level radioactive waste for large volumes of low (extremely low) radioactive solid waste such as uranium tailings. In recent years, the development of the paste backfill technique and its new cementitious materials have provided important ideas and references for the disposal of uranium tailings based on the principle of cement solidification [3][4][5]. Uranium tailings are different from the medium and low-level radioactive waste discharged by nuclear power plants.…”

The Influence of Slag/Fly Ash Ratio and Sodium Silicate Modulus on the Properties of 1-3-2 Alkali-Based Piezoelectric Composite

“…Instead of adding conductive material, replacing cement with materials with lower resistivity or minimizing the pores inside the composite could improve the piezoelectric and dielectric performance of the composite more effectively. Moreover, good compatibility could be achieved [ 21 , 22 , 23 ]. Therefore, a new solution is proposed in this paper.…”