An efficient MgAl2O4 spinel additive for improved slag erosion and penetration resistance of high-Al2O3 and MgO-C refractories

• Published in: Ceramics international Vol. 28; no. 3; pp. 245 - 253
• Main Authors: GANESH, I, BHATTACHARJEE, S, SAHA, B. P, JOHNSON, R, RAJESHWARI, K, SENGUPTA, R, RAMANA RAO, M. V, MAHAJAN, Y. R
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Science 2002
• Subjects: Applied sciences; Building materials. Ceramics. Glasses; Chemical industry and chemicals; Exact sciences and technology; Refractory products; Silica-alumina refractories; Special refractories; Behavior in operation; Densification; Magnesite carbon refractory; Magnesium Aluminates; Experimental study; Corrosion resistance; Additive; Penetration; Spinel; Sintering; Slag; Manufacturing; Chemical properties; High alumina refractory; Erosion
• ISSN: 0272-8842; 1873-3956
• DOI: 10.1016/S0272-8842(01)00086-4

A stoichiometric dense MgAl2O4 spinel was prepared according to a conventional double stage firing process using AlCl3 as a sintering aid. A stoichiometric mixture of aluminium trihydroxide and caustic MgO was calcined at 1300 C for 1 h in order to achieve a desired degree of spinelisation. AlCl3 in different amounts, i.e. 0.911, 1.822 and 2.733 wt%, was coated on spinelised powder using the wet impregnation technique and sintered at different temperatures ranging from 1500 to 1600 C for 1 h. Among the samples sintered at 1550 C for 1 h, spinel incorporated with 2.733 wt% AlCl3 exhibited superior properties in terms of bulk density, apparent porosity and water absorption. EDAX analysis revealed that AlCl3 as a sintering aid helps in reducing the Na2O present in the raw materials composition after sintering. EPMA studies revealed that the spinel prepared is comparable with commercial spinel. Finally, 20 wt% of the stoichiometric spinel incorporated with 2.733 wt% AlCl3 prior to sintering was added to high-Al2O3 and MgO-C refractories to evaluate its effect on slag erosion and penetration resistance as well as on repeated permanent linear change (PLC) of these bricks. The slag erosion and penetration resistance were improved remarkably, and the PLCs exhibited more stable positive values. 27 refs.