Bonding mechanism and performance of rectorite/ball clay bonded unfired high alumina bricks. Issue 8 (15th April 2021)

• Record Type: Journal Article
• Authors: Li, Xiaohui; Gu, Huazhi; Huang, Ao; Fu, Lvping
• Is Part Of: Ceramics international. Volume 47:Issue 8(2021)
• Page Start: 10749
• Page End: 10763
• Publication Date: 2021-04-15
• Subjects: Rectorite clay -- Ball clay -- Bonding mechanism -- Normal/high temperature performance -- Unfired high alumina brick; Ceramics -- Periodicals; Céramique industrielle -- Périodiques; Ceramics; Periodicals; Electronic journals; 666
• DOI: 10.1016/j.ceramint.2020.12.191
• Languages: English
• ISSNs: 0272-8842

Abstract

Abstract: In this study, the bonding mechanism and normal/high temperature performance of rectorite clay or ball clay bonded unfired high alumina bricks were investigated by using different techniques (XRD, TG-DSC, SEM, particle size distribution and rheology). The results showed that clay particles are separated into layer structural units in water due to the hydration swelling and electrostatic repulsive force, and rectorite layer structural units have larger aspect ratio than ball clay. Rectorite layer structural units form band-type structure with "face to face" after drying results in better bonding performance than ball clay (card-house structure with "edge to face"). The cold crushing strength of 9% rectorite/ball clay bonded unfired high alumina bricks after firing at the dehydroxylation temperature for 3 h reach 71 MPa and 50 MPa, respectively, and which can satisfy the strength requirement for the transportation and use of most high alumina bricks. The secondary mullitization and lower liquid phase content of ball clay bonded unfired high alumina brick under high temperature cause it has higher refractoriness under load and lower linear shrinkage than rectorite clay bonded brick. The T0.6 refractoriness under load of 9% rectorite/ball clay bonded unfired high alumina brick are 1262.6 °C and 1580.3 °C, respectively. Thus, the 9% ball clay bonded unfired high alumina bricks have wider service temperature range than 9% rectorite bonded bricks.