Production of Reactive Alumina from Domestic Sources and Its Use in Alumina-Based Self-Flowing Castable Refractories

Abstract

High-quality alumina raw materials allow corundum-based brick and monolithics to perform to the full potential of alumina as a refractory material. Dense packing of the matrix to a submicron range and reduction of water demand of castables can be facilitated by a new family of multimodal reactive alumina. Dispersing aluminas ensure uniform mixing of dispersion and setting adjustment additives. In this study, fine reactive alumina powder production was investigated using Bayer gibbsite as a starting material. Experimental studies consist of two steps; in the first step, the soda content was reduced by means of boric acid and distilled water and then the powders obtained optimum conditions were ground in an attritor ball mill using distilled water for 8 hours. In the second step, physical characteristics such as rheological behaviours, bulk density, open porosity and thermal shock resistance, bending and compressive strength and fracture toughness in accordance with ASTM E399 standard were determined. Finally, KIC values of the refractory samples which was prepared with the reactive alumina produced from Seydişehir gibbsite were higher than that of the refractory mixture containing commercial reactive alumina obtained from a refractory company.

Keywords

• Seydişehir gibbsite
• Reactive alumina
• Self-flowing castable refractories
• Fracture toughness

References

1. Akselrod MS, Bruni FJ. 2012. Modern trends in crystal growth and new applications of sapphire. J Crystal Growth, 360: 134-145.
2. Buhr A, Laurich J O. 2000. Synthetic alumina raw materials--key elements for innovative refractories. Metallurg Plant Technol Inter (Germany), 23(3): 62-64.
3. Chang PL, Wu YC, Lai SJ, Yen FS. 2009. Size effects on χ-to α-Al2O3 phase transformation. J European Ceramic Soc, 29(16): 3341-3348.
4. Fu X, Tang W, Ji L, Chen S. 2012. V2O5/Al2O3 composite photocatalyst: preparation, characterization, the role of Al2O3. Chem Engin J, 180:170-177.
5. Gogtas C, Lopez HF, Sobolev K. 2014. Role of cement content on the properties of self-flowing Al2O3 refractory castables. J European Ceramic Soc, 34(5): 1365-1373.
6. Göğtaş C, Ünlü N, Odabaşı A, Sezer L, Cınar F, Güner Ş, Göller G, Eruslu N. 2010. Preparation and characterisation of self-flowing refractory material containing 971U type microsilica. Advan Applied Ceramics, 109(1): 6-11.
7. Gürel SB, Altun A. 2009. Reactive alumina production for the refractory industry. Powder Technol, 196(2): 115-121.
8. Lee JS, Kim HS, Park NK, Lee TJ, Kang M. 2013. Low temperature synthesis of α-alumina from aluminum hydroxide hydrothermally synthesized using [Al(C2O4) x(OH) y] complexes. Chem Engin J, 230:351-360.

9. Lee W, Vieira W, Zhang S, Ahari KG, Sarpoolaky H, Parr C. 2001. Castable refractory concretes. Inter Materials Rev, 46(3): 145-167.
10. Luz A, Gabriel A, Consoni L, Aneziris C, Pandolfelli V. 2018. Self-reinforced high-alumina refractory castables. Ceramics Inter, 44(2): 2364-2375.
11. Ma W, Brown PW. 1999. Mechanisms of reaction of hydratable aluminas. J American Ceramic Soc, 82(2): 453-456.
12. Madono M. 1999. Alumina raw materials for the refractory industry. CN-Refractories, 6(3): 54-63.
13. Otroj S, Sagaeian A, Daghighi A, Nemati ZA. 2010. The effect of nano-size additives on the electrical conductivity of matrix suspension and properties of self-flowing low-cement high alumina refractory castables. Ceramics Inter, 36(4): 1411-1416.
14. Schnabel M, Buhr A, Kockegey-Lorenz R, Schmidtmeier D, Dutton J. 2014. Benefit of matrix alumina and modern dispersing systems in low cement castables. Interceram-Inter Ceramic Rev, 63:281-285.
15. Silva AP, Segadães AM, Pinto DG, Oliveira LA, Devezas TC. 2012. Effect of particle size distribution and calcium aluminate cement on the rheological behaviour of all-alumina refractory castables. Powder Technol, 226:107-113.
16. Xie ZP, Lu JW, Huang Y, Cheng YB. 2003. Influence of α-alumina seed on the morphology of grain growth in alumina ceramics from Bayer aluminum hydroxide. Materials Letters, 57(16-17): 2501-2508.
17. Zhu L, Liu L, Sun C, Zhang X, Zhang L, Gao Z, Ye G, Li H. 2020. Low temperature synthesis of polyhedral α-Al2O3 nanoparticles through two different modes of planetary ball milling. Ceramics Inter, 46(18): 28414-28421.