Technical Paper
A-M-CMA castables and compared corrosion of samples than can expand freely with samples that are put under constraint. It was found that the suppressed expansion has a positive effect on the corrosion resistance.
Steel foundry ladles
A 8t steel foundry ladle was installed with a CMA-bonded A-MA castable [25]. Compared to the reference material that used 70% alumina cement and spinel powder with the same total amount of spinel and CaO in the castable, a significantly better and more homogeneous wear profile was observed after 250 heats. The remaining castable thickness was still more than 10 cm (Fig. 9) and more heats compared to the reference material were achievable.
REFRACTORIES ENGINEER
THE
Fig. 11: Bulk density of A-MA castables [18]
Interface with substrate
Fig. 9: 8t-steel foundry ladle with CMA-bonded castable after 250 heats
Slagging gasifiers Spinel containing castables for slagging gasifiers were investigated with the aim of designing chromium oxid-free castables [26, 27, 28, 29]. The investigation included investigations of corrosion of magnesium- aluminate spinel rich refractories including CMA by Sulphur-containing slags. The studies included castables that contained mainly MA-spinel aggregates bonded with between 2 and 18% CMA 72. It was found that amongst the tested chromium-free samples the superior slag resistance was achieved with a castable that contained 6% CMA72.
Aluminium furnaces
Pawlig et al. [30] investigated the effect of CMA-binder in refractory castables for aluminium contact application. They reported that the smaller pore sizes relative to a matrix composed of classical blend of calcium aluminate + MA-spinel had a positive effect on the penetration resistance in a bauxite castable both with and without the addition of Barium Sulfate as anti-wetting agent (Fig. 10).
Fig. 12: CMOR of A-MA castables [18]
Fig. 13: A-MA castables after slag attack [18]
Fig. 10: Aluminum alloy resistance of a Bauxite castable with CMA 72, without anti-wetting agent [28]
Fig. 14: Permanent linear change of A-MA castables
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