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US 4,049,440 AGranted
Method for producing metallic iron pellets
AssigneeMidrex Corporation
InventorDonald Beggs
Life of this patent
Estimating the term…
Abstract
A method of producing metallic iron pellets in a generally vertical furnace in which a gravitational flow of particulate material is reduced in a reducing zone by a countercurrent flow of a reducing gas containing a reductant, the spent reducing gas is removed and cooled and a portion is introduced as cooling gas in a cooling zone near the bottom of the furnace, and a portion of the cooling gas is upgraded in reducing potential and introduced to the reducing zone as reducing gas.
Claims19
A method for producing a metallized product comprising:
- a. establishing a gravitational flow of particulate metal oxide material by charging the particulate metal oxide material to the upper portion of a generally vertical furnace having an upper reducing zone and a lower cooling zone, and removing the metallized product from the bottom of the furnace;
- b. introducing a reducing gas to the gravitational flow of material at a temperature sufficient to promote a reducing reaction between said reducing gas and said material at a first inlet intermediate the ends of the furnace;
- c. causing said reducing gas to move countercurrent through the gravitational flow of material, react with and reduce a substantial portion of the metal oxide and form a top gas;
- d. removing said top gas from the upper portion of the furnace;
- e. cooling said top gas;
- f. introducing a cooling gas into a second inlet near the lower end of said furnace;
- g. removing a portion of said cooling gas from said furnace at a location intermediate said first and second inlets;
- h. cooling the removed portion;
- i. introducing the cooled removed portion to said second inlet to form a recirculating circuit including the cooling zone;
- j. adding cooled top gas to said recirculating circuit;
- and
- k. causing a second portion of said cooling gas, in an amount substantially equal to the amount of cooled top gas added to said recirculating circuit, to flow upwardly through the gravitational flow of material, become heated thereby, and to flow into and act as a reducing gas in the reducing zone;
- whereby, that portion of said cooling gas flowing upwardly through the gravitational flow of material has a greater reducing potential than the spent top gas, and is thus an effective reductant.
10 more elements
A method for producing metallized iron pellets comprising:
- a. establishing a gravitational flow of iron oxide material in a vertical shaft furnace;
- b. introducing a gaseous reductant at an intermediate location within said furnace through a first inlet;
- c. causing said gaseous reductant to move in counterflow relationship through the descending iron oxide material, reacting with said material, reducing a substantial portion of the iron oxides therein and forming spent top gas;
- d. removing the top gas which is the reacted gaseous reductant from the upper portion of the furnace;
- e. cooling said top gas;
- f. introducing a portion of the cooled top gas to a recirculating cooling gas circuit as a cooling gas directed into the vertical shaft furnace at a second inlet below said first inlet whereby said cooling gas is in direct heat exchange relationship with the descending material;
- g. causing a first portion of said cooling gas to flow upwardly from said cooling gas circuit and act as reductant, said first portion being substantially equal to the amount of cooled top gas introduced to said cooling gas circuit;
- h. removing a second portion of the cooling gas from said furnace at an outlet intermediate to said first and second inlets;
- i. removing from said removed cooling gas a portion of the water contained therein;
- j. cooling said removed cooling gas;
- and
- k. introducing the cooled and removed cooling gas into the second inlet, whereby the cooled top gas and removed cooling gas together upon reacting with the metallized material between said second inlet and said outlet have a greater reducing potential than does the spent top gas.
9 more elements
Dependencies are inferred from the claim text.