Organic binder as a substitute for bentonite in ilmenite pelletization

Abstract

TiZir Titanium & Iron produces high titania slag and high purity pig iron from ilmenite in Tyssedal. The ilmenite is pelletized before smelting. Bentonite is added to the ilmenite concentrate as a binder to give the pellets strength and durability. Bentonite consists mainly of silica and alumina, which are considered as impurities in the high titania slag production. The use of organic binder has therefore been suggested as a substitute for bentonite.This work has focused on developing knowledge on the pelletization process and investigating various organic binders.Two methods of agglomeration, pelletization and briquetting, have been used in this work. Three batches of pellets have been made using a laboratory scale pelletizing drum. Two organic binders, Peridur 300 and Peridur 330, have been tested and compared to pellets made with bentonite and without binder. Seven batches of briquettes have been made using a cylindrical mold and a piston. Three organic binders, Peridur 300, calcium lignosulfonate and a nano cellulose fibre have been tested and compared to briquettes made with bentonite and without binder. The characterization included drop number test (pellets only), compression strength and thermal treatment.Briquettes were employed because using pellets yielded large deviations in the results. These deviations were believed to stem from the varying geometry of the pellets and were substantially mitigated by the use of cylindrical briquettes. It was found that Peridur 300 is a potential alternative to bentonite. The findings from thermal treatment suggest that above 500 degrees celcius sintering takes over as the dominating binding mechanism. For green strength, increasing binder viscosity has a positive effect.