US EPA

3007857 

Journal Article 

CHROMIUM-FREE COMPLEX SPINEL BONDED BASIC CASTABLES 

Lodha, R; Zargar, H; Troczynski, Tom; Oprea, G 

2014 

1291-1296 

WOS:000348596100218 

This study presents the experimental results of processing and sintering of chromium-free spinel bonded basic castables through the use of ultra-fine particles and spinel forming oxides that can create metastable phases leading to the formation of a complex spinel solid solution. The metastable phases formed during the low temperature reactions lead to an activated synthesis of the complex spinel. The subsequent reaction of the formed spinel matrix bonding to the basic aggregates was achieved, which resulted in lower temperatures of synthesis and sintering of the spinel phases. The binder system based on in-situ spinel forming technology allows the matrix of the castables to sinter at 5% open porosity, when fired below 1500 degrees C. The effects of commercial dispersants on the flow and setting behavior of the castables were studied. The effect of the aggregate hydration on green properties of the castables was also studied in order to understand the impact of brucite formation on the flow and working time of the castables and their subsequent fired properties. Castables using our novel chromium-free spinel bonding system, fired at as low as 1450 degrees C, have been scaled up to industrial size and tested in an industrial nonferrous Bottom Blown Oxygen Furnace (BBOC). They showed similar properties and behavior in use to the industrial rebonded fused grain (RFG) grade of magnesia-chrome basic bricks, which are considered at this time the best for non-ferrous applications.