Transforming submerged-arc welding slags into magnetic glass-ceramics

Figures & data

Figure 1. Photograph of the slag welding flux generated during submerged-arc welding process.

Table 1. Chemical composition of the investigated SAWS (wt%).

Elements	%	Elements	%	Elements	%
SiO2	23.092	F	1.682	SO3	0.127
Al2O3	22.348	Na2O	1.682	SrO	0.082
MnO	18.586	K2O	1.273	PbO	0.057
CaO	11.201	Co3O4	0.304	CuO	0.032
MgO	8.805	BaO	0.300	ZnO	0.017
Fe2O3	6.038	ZrO2	0.221	L.O.I	0.105
TiO2	3.889	P2O5	0.159

Figure 2. XRD of the as-received slag welding flux. CaF₂ (F); Mullite (M); Rutile (R); Al₂O₃ (Al); (Mn₂O₃)₃MnSiO₃ (B); Periclase (P); Quartz (Q); Cristobalite (C).

Figure 3. Variation in porosity with different RH percentages and temperatures.

Figure 4. Variation in water absorption capacity with different RH percentages and temperatures.

Figure 5. XRD patterns of powder samples of 1% RH sintered for 1 h at the indicated temperatures. D–diopside; J-jacobsite; C-corundum; M-MgAl₂O_4; P-pyrope; S-SiO₂ Z-Ca_1.82 Al_3.64 Si_0.36O_8.

Figure 6. XRD patterns from powder samples of 20% RH sintered for 1 h at the indicated temperatures. D–diopside; J-jacobsite; C-corundum; M-MgAl₂O_4.

Figure 7. Image aspects of the porous glass–ceramic structures containing 20% RHs and sintered at various temperatures (a) 900 °C, (b) 975 °C, (c) 1000 °C and (d) 1000 °C at 6% RH.

Figure 8. SEM of a sample sintered for 1 h with incorporation of 1% RH at 900 °C.

Figure 9. SEM of a sample sintered for 1 h with incorporation of 1% RH at 1000 °C.

Table 2. Quantitative elemental composition of the crystals in Figure 8.

Element	Atomic % (Spectrum 2)	Atomic % (Spectrum 3)
O	63.58	58.2
Na	7.90	6.64
Mg	2.93	3.36
Al	2.16	3.17
Si	19.57	20.42
Ca	2.69	5.13
K	0.18	0.2
Mn	0.40	0.76
Fe	0.48	1.76
Ti	0.11	0.37

Table 3. Quantitative elemental composition of the crystals in Figure 9.

Element	Atomic % (Spectrum 1)	Atomic % (Spectrum 2)
O	63.96	60.87
Na	5.90	2.36
Mg	3.09	1.91
Al	6.28	22.60
Si	17.05	9.28
Ca	2.75	1.93
K	0.15	–
Mn	0.41	0.43
Fe	0.41	0.62

Figure 10. SEM of a sample sintered for 1 h with incorporation of 20% RH at 1000 °C.

Figure 11. Magnetization curves of porous glass–ceramic containing 20% RH and sintered at 1000 °C for 1 h.

Table 4. Magnetic properties of the porous glass–ceramics. M_s, M_r and H_c are saturation magnetization, remanence and coercivity, respectively.

Sample	Ms (emu/g)	Mr (emu/g)	Hc (Oersted)
1000 °C (1% RH)	0.818	71 × 10^−3	151.8
1000 °C (20% RH)	0.815	64 × 10^−3	141.91
900 °C (1% RH)	0.83	75.5 × 10^−3	159