Abstract
A key in design and operation of the direct reduction shaft furnace is to prevent iron ore pellets from clustering. A new rotating type shear tester was developed to measure the shear strength of the pellets during reduction and to relate it to the flow condition. The size of the cell is 144mm O. D. and 80mm I. D., and the pellets in the cell are reduced by using CO gas at the temperature elevated to 980°C. The maximum load on the cell is 3.40kN for consolidation and 0.86kN during shear. The measured shear strength of the reduced pellets was from 40 to 70kPa, and it was decreased approximately to half by shearing continuously during reduction.
