Development of a Cementless Cold-bonded Pellets Process

Abstract

At NSC Kimitsu Works, we have recently developed cementless cold-bonded pellets process using ground-granulated blast-furnace slag containing gypsum as a binder instead of cement. Ground-granulated BF slag hardens only when an alkali activator and water were added because of latent hydraulicity. We confirmed the effect of an alkali activator, water and atomospheric temperature ( curing temperature) on the hardening speed by pilot test. As a result of the tests, we developed cementless cold-bonded pelletizing process which shows same hardening speed as with cement. And the properties of cementless cold-bonded pellets are almost same and superior to those of cement cold-bonded pellets. So we have made a commercial plant that produced 40 000 t/month, and now we use 3% cold-bonded pellets for blast-furnace burden with good operating results.