Mechanical Activation of Granulated Copper Slag and Its Influence on Hydration Heat and Compressive Strength of Blended Cement

Abstract

Mechanical activation of granulated copper slag (GCS) is carried out in the present study for the purposes of enhancing pozzolanic activity for the GCS. A vibration mill mills the GCS for 1, 2, and 3 h to produce samples with specific surface area of 0.67, 1.03 and 1.37 m2/g, respectively. The samples are used to replace 30% cement (PC) to get 3 PC-GCS binders. The hydration heat and compressive strength are measured for the binders and derivative thermogravimetric /thermogravimetric analysis (DTG/TGA), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM) are used to characterize the paste samples. It is shown that cumulative heat and compressive strength at different ages of hydration and curing, respectively, are higher for the binders blending the GCS milled for a longer time. The compressive strength after 90 d of curing for the binder with the longest milling time reaches 35.7 MPa, which is higher than the strength of other binders and close to the strength value of 39.3 MPa obtained by the PC pastes. The percentage of fixed lime by the binder pastes at 28 days is correlated with the degree of pozzolanic reaction and strength development. The percentage is higher for the binder blending the GCS with longer milling time and higher specific surface area. The pastes with binders blending the GCS of specific surface area of 0.67 and 1.37 m2/g fix lime of 15.20 and 21.15%, respectively. These results together with results from X-ray diffraction (XRD), FTIR, and SEM investigations demonstrate that the mechanical activation via vibratory milling is an effective method to enhance the pozzolanic activity and the extent for cement substitution by the GCS as a suitable supplementary cementitious material (SCM).

Alkali Activation of Copper and Nickel Slag Composite Cementitious Materials

“…The absorption peak wavelengths of the ACNCMs hydration products were mainly around 3446, 1652, 1486, 1423, 956, 873, and 477 cm −1 . Among them, 3446 and 1652 cm −1 respectively represented the asymmetric stretching vibration and bending vibration of the combined water −OH group [33]. Additionally, 1486 and 1423 cm −1 were classified as CO 2− 3 vibrations [34,35].…”

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

“…Slag-based cementitious materials generally have the advantages of corrosion resistance and high post-strength and can also solve the problems of expansion, strength reduction, and even disintegration of high-sulfur tailing aggregate filling body [14][15][16][17][18][19][20][21]. Geopolymer cementitious materials have a "crystal-like" structure consisting of circular molecular chains, which can segment metal ions and other toxic substances into cavities and which is one of the effective methods for toxic and nuclear waste treatment [22][23][24][25][26].…”

Preparation of a New Type of Cemented Paste Backfill with an Alkali-Activated Silica Fume and Slag Composite Binder

“…Katpady et al [29] prepared a geopolymer using shirasu as an aluminosilicate, sodium hydroxide and water glass as an alkali activator, and slag as an additive, and they concluded that the UCS and acid resistance of the specimens were significantly improved with the addition of slag compared with no slag addition. Feng et al [30,31] used mechanical activation and the incorporation of calcium oxide to improve the pozzolanic activity of granular copper slag (GCS); they also prepared a binder, as well as a suitable binder for formulating CPB. Jiang et al [32,33] studied the early strength and working characteristics of CPB using alkali-activated slag as a binder; they also studied the change in yield stress of CPB under different low temperatures and time conditions.…”