PREPELLETIZING METHOD FOR RAW MATERIAL TO BE SINTERED ENABLING USE OF LARGE AMOUNT OF FINE POWDER ORE

PURPOSE:To provide prepellets which do not degrade air permeability at the time of sintering even if a large amt. of fine powder ore is used. CONSTITUTION:The average grain sizes of the fine powder ore sticking to the surfaces of coarse grain raw materials to constitute nuclear particles and other raw materials to be sintered are determined at the time of producing the raw materials to be sintered for charging into a blast furnace by compounding the fine powder ore contg. >=80% particles of =50% particles having grain sizes exceeding 1mm. A void volume epsilon of the sticking powder layers is estimated from these average grain sizes and the compounding ratios of the fine powder ore and the other raw materials to be sintered with the coarse grain raw materials to constitute the sticking powder layer are so adjusted that the void volume epsilon attains