Good pumpability of low water demand castables is a key technical challenge for high performance, high purity castables based on Tabular alumina and Spinel. Additions of microsilica to achieve the desired rheology for pumping at reasonable pressure in piston pumps used for pumpcasting arid shotcreting is not an option since it would reduce the thermo-mechanical strength at high temperatures and reduce the corrosion resistance. The challenge was to develop alumina matrix concepts, which give castables a low dilatancy even tinder extreme shear conditions as exists in double piston pumps. The products E-SY 1000 and 2000 are solutions to this challenge. Trials have proven that Tabular alumina castables using E-SY 1000 and E-SY 2000 as matrix aluminas fulfill the rheological requirements of these pumps. The difference between E-SY 1000 and E-SY 2000 is their chemical composition. E-SY 1000 contains only alumina components and E-SY 2000 contains alumina and alumina-rich Spinel. It is well known in the industry that the addition of fine alumina-rich AR78 Spinel to castables will significantly increase both slag resistance and hot strength. E-SY 2000 combines superior pumpability with the advantages of alumina-rich Spinel. The use of E-SY 2000 will be of high interest, for example, in steel ladle applications. The paper will discuss the properties and application results of the new aluminas based on laboratory tests and field trials.
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