Shaft furnace design

Claim 1

In a shaft furnace for the direct reduction of oxidic ore including an upstanding refractory lined, metallic shell defining a chamber in which ore is reduced by intimate contact with reducing gas, said shell having ore supply and discharge openings for passing ore by gravity from top to bottom through said chamber and a downwardly convergent transition section adjacent said ore discharge opening, high temperature reducing gas inlet means communicating with said chamber at an intermediate region thereof and effective to pass said high temperature gas in counterflow relation to the flow of ore therethrough, means for introducing cool reducing gas adjacent said ore discharge opening for flow in counterflow relation to said ore, improvement comprising means for regulatably passing said cool reducing gas through each of a plurality of concentrically spaced transverse sections of said shell, said means comprising a transition section including: (a) a plurality of hollow, conical frustrums disposed in mutual telescoping relation depending from the lower end of said shell; (b) axially spaced, annular plates interconnecting said frustrums and cooperating therewith to form a plurality of axially spaced annular manifolds of progressively reduced diameter extending about the periphery of said transition section, (c) circumferentially spaced openings in said plates establishing gas communication between said manifolds and said chamber; (d) circumferentially spaced partition plates in said manifolds for dividing the same into separate compartments; and (e) means for independently regulating the supply of cool reducing gas to each of said compartments.