Studies of the stability of β-Ca2SiO4 doped by minor ions

The influence of heavy metals on the polymorphs of dicalcium silicate in the belite-rich clinkers produced from electroplating sludge

“…2 and 3 show the weight fraction of ␥-C 2 S and ␤-C 2 S in the clinkers, respectively. The reference clinker, which was not doped with heavy-metal oxides, contained about 27 wt.% of ␥-C 2 S and 34 wt.% of ␤-C 2 S. The stabilized ␤-C 2 S may be attributed to Al 3+ and Fe 3+ , which has been reported in several previous studies [16,18,19]. In those studies, Al 3+ and Fe 3+ were doped into a pure CaO-SiO 2 sys- tem at 0.01-0.2 mol for 1 mol of C 2 S, and it was reported that Al 3+ and Fe 3+ could stabilize C 2 S in the ␤ phase, which was contrary to the judgments for the determination of stabilizing ions [20][21][22].…”

“…Chan et al [15] reported that the C 2 S particles smaller than 10 m were completely retained as the ␤ phase. The effects of foreign ions on chemical stabilization have also been investigated [16][17][18][19], and various judgment methods based on the Goldschmidt's ion radius (R G ) [20], the ratio of charge to Pauling's ion radius (C/R P ) [21], and the ion polarization ability (C 2 /R P ) [22] have been proposed to predict which ions can stabilize ␤-C 2 S at room temperature. Generally, the chemical approaches in the literature were effective in stabilizing ␤-C 2 S, without particularly controlling the cooling conditions or the particle size.…”

The effect of chemical composition on the leaching behaviour of electric arc furnace (EAF) carbon steel slag during a standard leaching test

“…52 Even if the conditions under which the leachates are produced 53 vary as a result of different physical parameters like pH, 54 temperature, or flow conditions, and influence the resulting 55 concentrations of metals in the leachates [18], the slag chemical 56 composition covers an important role on immobilization, or the 57 release of the above mentioned toxic elements. For example, MgO 58 concentration in the slag seems to be favourable for Cr 59 immobilization but detrimental for the leaching of other 60 polluting elements, i.e. Ba and V [19].…”

Ab InitioCalculations for the Substitutions of Al(OH)-4and SO2-4with Si Tetrahedra

“…With this energy, the substitution of SO 4 with Si tetrahedra. [5][6][7][8][9][10][11][12][13][14] A comparison of the calculated values with the experimental results could be conducted by considering more relaxed atoms with the surrounding water molecules in the calculation procedures.…”

“…[5][6][7][8][9][10][11][12][13][14] However, there is no clear evidence regarding the interaction of C-S-H gel and AFt in these experimental as well as in the theoretical studies. These substitutions generally take place in the structure of C-S-H gel by substituting with paired and bridging Si tetrahedra especially at C/S>1.…”