Investigation on Stabilization of Ladle Furnace Slag with Different Additives

Abstract

Ladle furnace slag disintegrates into fine powder during cooling due to phase transformations of di-calcium silicate. This creates an adverse impact on working conditions and the environment by dust generation. In this paper, a short overview on different studies to overcome the disintegration problem is provided. An attempt was also made to study the effects of several different additives and their mixtures on disintegration of slag. Phase equilibria calculations were carried out for some additives using FactSage ® to understand the phase changes in the slag. Based on the phase equilibria calculations and literature data, initial laboratory experiments were conducted at 1650°C with different additives such as boric acid, aluminium and fly ash. Slag samples were analysed with XRF and XRD for chemical and phase analysis before and after treatment. The disintegration of slag can be prevented either by addition of 0.5 wt% or more of boric acid or 9 wt% of aluminium or 6 wt% of fly ash or 4-8 wt% fly ash along with 0.125-0.25 wt% of boric acid in slag. Based on the optimised conditions, industrial trials were conducted.

Recovery of Iron and Aluminum from Bauxite Residue by Carbothermic Reduction and Slag Leaching

“…Samples 1.1 and 2.1 display opposite cracking behavior, despite both capturing significant amounts of Si in C2AS. Small concentrations of various oxides have proven to have a stabilizing effect by forming solid solutions with C2S [28]. A recent study found that the addition of up to 3% of TiO 2 effectively stabilized the β-polymorph by substituting Si 4+ in the SiO 4 2− tetrahedron with Ti 4+ [29].…”

Utilization of ladle slag for soil stabilization

“…In the past few years, many scholars presented the elemental analysis of LS using X-ray fluorescence (XRF) and found that the types and quantities of LS were not all the same. Nevertheless, the main chemical compositions of LS are similar, as shown in Table 2.1 (Adesanya et al 2017a(Adesanya et al , 2017b(Adesanya et al , 2020Adolfsson et al 2011;Bocci 2018;Gijbels et al 2020;Gollapalli et al 2020;Manso et al 2005;Moliné et al 2018;Monkman et al 2009;Montenegro et al 2012;Murri et al 2013;Papayianni and Anastasiou 2012;Pinheiro et al 2020;Rađenović et al 2013;Salman et al 2015;Setié n et al 2009;Shi 2002;Skaf et al 2016;Tossavainen et al 2007;Yildirim and Prezzi 2017).…”

“…The heavy metals in LS are also detected in several studies. From Table 2.3, MnO, Cr2O3, and ZnO are the main detected heavy metal oxides (Adesanya et al 2020;Adolfsson et al 2011;Bignozzi et al 2013;Bocci 2018;Gijbels et al 2020;Gollapalli et al 2020;Herrero et al 2016;Rađenović et al 2013;Salman et al 2015;Setié n et al 2009;Shi 2002;Tossavainen et al 2007;Yildirim and Prezzi 2017).…”

“…During this refining process, caked slag will be generated after dumping and then becomes disintegrated slag after cooling, as shown in Fig. 2.2(b-c) (Gollapalli et al 2020;Guzzon et al 2007). This disintegrated slag is generally referred to as ladle furnace slag or ladle slag.…”

“…It is found that most data are located on the left-bottom side, implying that most LS has a high content of CaO, moderate content of SiO2, and low content of Al2O3. Several studies also reported the presence of K2O, TiO2, SO3, and Na2O in LS, but the quantities are too small (Adesanya et al 2020;Bocci 2018;Gollapalli et al 2020;Monkman et al 2009;Papayianni and Anastasiou 2012;Pinheiro et al 2020;Setié n et al 2009;Skaf et al 2016). MgO in LS will cause volume expansion and potential soundness problems with the long-term hydration and carbonation reactions (Montenegro et al 2012;Shi 2002).…”