US1786999A - Reduction of metals from ores - Google Patents

Description

Dec. 30, 1930, J. w. HORNSEY REDUCTION OF METALS FROM ORES 2 Sheets-Sheet 1 Original Filed Nov. 2 1925 w w *1 w Dec. 30, 1930. w. HORNSEY 1,786,999

'REDUCTION oF METALS FROM ORES Original Fi led Nov. 25, 1925 2 Sheets-Sheet 2 QWW Patented Dec. 30, 1930 UNITED STATES PAT NT OFFICE JOHN WILLIAM HORNSEY, OF NEW YORK, N. Y., ASSIGNOR TO GRANULAR IRON COM- PANY, CORPORATION OF MICHIGAN REDUCTION OF METALS FROM ORES Original application filed November 25, 1925', Serial No. 71,442. Divided and this application filed September 27, 1928.

This invention relates to the reduction of metal from ores and it is particularly useful for the reduction of iron ore in connection with which it will be described.

This application is a divisionof my 00- pending application Serial No. 71,442 filed November 25, 1925 now Patent No. 1,690,820.

One of the primary objects of my invention is to simply and effectively reduce ores without going t rough the molten state, that is to say, to solidly reduce the metal and. to lessen the cost of producing the same.

How the foregoing, together with such other objects as may hereinafter appear, or are incident to my invention, are realized, is illustrated in the accompanying drawings in preferred form whereih- Fig. 1 is a diagrammatic side elevation of the apparatus I employ in carrying out my invention;

Fig. 2 is a section taken on line.2-2 of Fig. 1;

Fig. 3 is a section taken on the line 33 of Fig. 1, and

Fig. 4 is a vertical section through a portion of the apparatus illustrating details of my invention.

Referring now to Fig. 1, I take the ore in a suitable state of sub-dlvision say, for example, crushed so as'to pass through a 4 inch mesh screen, and deliver it from the hopper 7 into a preheating cylinder 8. The material is fed from the hopper into the heating cylinder by means of the screw conveyor 9 and the pipe 10, the screw conveyor preferably terminating short of the inner end of the pipe 10 so that the ore piles up beyond the end of the screw and is pushed-in the form of a plug which excludes air from entering through the feeder mechanism into the cylinder 8. The feeder pipe projects through a stationary chamber 11 whlch has a seal 12 to be more particularl described hereinafter, whereb a substantial y gas tight connection is had etween the revolving cylinder 8 and the stationary chamber 11. Leading from the chamber 11 is a damper controlled stack 13 for carrying off the said gases.

Serial N0. 308,798.

ature of reduction, the heat being preferably supplied by the hot gases'leaving the succeeding cylinder 14, supplemented by the introduction of such additional fuel as may be required through the burner 15 which passes through the stationary casing 16 at the right hand end of the cylinders 8 and 14. A The cylinder 8 has a seal 12, as above, affording a substantially gastight connection as between the cylinder and the casing 16. Thus, no air can enter into the cylinder8 except such as may be deliberately supplied under control through the pipe 17 and the burner 15 passing through the casing 16. Air required for burning the fuel admitted to the cylinder 8. is supplied through this pipe 17 and the burner 15, and I find it desirable to'maintain a reducing atmosphere at the discharge end of the cylinder 8 and a' slightly oxidizing atmosphere at the feed end. The cylinder 8 is revolved by any suitable driving mechanism such as that indicated and it is to be noted that the inclination of this cylinder, as well as all other cylinders employed in my apparatus, is very slight in order that the grosser particles of the ore shall not move toq rapidly in advance of the fine particles, the object being to cause the gross and fine particles to move as nearly as possible together. This, Ihave found, materially increases the capacity and as .a desirable degree of inclination I mention l-inch to four feet.

The heated materialdischarging out of the cylinder 8 into the casing 16 falls by gravity through the casing 16 and into the right hand end of the cylinder 14, which cylinder has a rial as it falls into the cylinder 14 meets with reducing agent introduced through the pipe 18, such reducing agent being f discharged into the casing 19 constructed substantially the same as the casing 16, there beseal 12 in the casing 16 as above. The matei tion nowtakes place and the material gradually moves toward the lower end f vof the cylinder 14 from which it is eventually ing a seal 12 between the cylinder 14 and the casing 19.

As the reaction of reduction with coal as the reducing agent is endothermic, there is a tendency for the temperature to become too low and, therefore, I introduce fuel, such as pulverized coal, through the casing 19 into the cylinder 14 bymeans of the burner 20. This burner is preferably so constructed as to substantially prevent the air for combustion thereof coming into contact with material being reduced, thereby preventing oxidation of the iron. To this end, I introduce the fuel with a small amount of carrying air, say,

for example, 25 percent of the air required.

for combustion through the burner pipe 21, extending into which is an air nozzle 22 providing an annular space 23 through which the coal and carrying air passes. The coal and carrying air is thus caused to assume a cylindrical form, the air admitted through the nozzle filling the center of the cylinder of coal and air. Immediately beyond the end of the nozzle 22 I provide a-venturi like portion 24. I prefer a pounds per square inc in the nozzle 22 and about a 2-ounce pressure in the burner pipe 21. By virtue of these pressures the controlled admission of air and the arrangement shown, the coal very largely surrounds the central core of air and the flame may be caused to travel a substantial length and the air for combustion to have an opportunity to combine with the combustile elements of Y the fuel before the gases so formed come into contact with the material being treated, also, the air itself cannot come into detrimental contact with the material being reduced which is indicated at 25 in Fig. 2. It will also be seen on inspection of this figure that the burner 20 is locatedwell toward the wall of the cylinder, that is to say, removed from the material within the cylinder.

Thus, as is the case with cylinder 8, air is excluded from the cylinder 14 with the exceptionof such air as is required for burning the fuel for heating the cylinder and this air is admitted under control.

The material leaving the cylinder 14 falls from the casing 19 into the ,cooling cylinder 26, there being a seal 12 between such cylinderand the casing 19. The cylinder 26 is subjected to a cooling means such as water discharge from the 'pe 27, the length of the cylinder being-such that the material is 'cooled below the point at which any appreciable oxidation can occur before it is ultilower endof the cylinder 26 discharges into- .60

mately' discharged to the atmosphere. The

the casing 28, there being a seal 12'between the cylinder and the casing. The discharge end -of' the cylinder .26 is perforated or foraminous, the size of the holesv 29 being such as to only permit thematerial being treated to pass therethrougli.v This materessure of about 40- rial discharges on to the plate or chute 30, the lower end of which is curved to provide a trough, in which works a conveyor screw 31. This conveyor screw 31 terminates short of the end of the discharge pipe 32 of the easing 28 so that the material forms a lug for such pipe, acting as a seal exclu ing an which would otherwise be drawn into the cylinder 26 and thence into the other cylinders.

If for any reason bricks forming the lining of the cylinders 8 and 14 should become dislodged and work down through the cynnder 26, theycannot discharge on to the plate 30 but pass bevond and fall on to the plate 33 for subsequent removal through the door 34. Thus the conveyor screw 31 is protected.

The material discharged from the pipe 32 1 able fastening means being employed. This ring, therefore, revolves with the cylinder. Concentric with\ the ring 36, but spaced away therefrom, is a wearing ring or shoe 38 and connecting these two rings is a corru ated metallic diaphragm 39, this diaphragm 'eing held to the ring 36 by meansof a ring 40 and a stud '41 with lock nut 42. A similar ring 43 secures the outer edge of the diaphragm 39 to the shoe 38 studs 44 being employed for this purpose. l3y this arrangement there is a tight joint between the diaphragm and the ring 36 and between the diaphragm and-the ring 38. The ring 38 bears u on the annular flange 45, forming a part0 the casing 16. A plurality of yokes 46 hold the shoe 38 against the flange 45, these yokes being If the longitudinal axis of the cylinder 9 should shift, the shoe 38 "will merely slide one way or another on the flange 45. This seal is a ver important part of my invention and I have ound it entirely reliable in operation. The simplicity of the seal will readily be appreciated. It is to be understood that the diaphra fastened to t e stationary chamber 16 an the and connected parts ma be shoe 38 made to contact with a ring similar to ring 45 attached to the cylinder.

Reverting now to the desirability of introducing the reducing fuel at the point where thematerial discharges from the casing 16 into the cylinder 14, it will be seen that the reducing agent is immediately brought into contact with the material and is entrained with it, so to speak, becoming embedded therein and thoroughly mixed therewith instead of being segregated. Reducing action is thus immediately initiated and effectively continned-at, all points throu bout the material so that not only the time of reduction but also the quantity of reducing material employed is reduced to a minimum. Since the ore is not melted and the temperatures employed are considerably lower than is customary, it will be obvious that there is a very heavy saving in fuel as compared to standard practice.

The product, ifiron ore be the materialtreated, is very pure iron. It is not sponge iron as that term hasbeen heretofore used'in this art. At the temperatures which exist and other conditions and the general environment, no iron cyanogen compounds can be formed or absorbed and hence the iron contains no ferrite dissolved nitrides, which are objectionable.

In any event, the iron is rust resisting to a most remarkable degree and when it is used in the making of steel, it produces a steel, the properties of which are far in excess of steel containing iron produced in the usual ways.

What I claim is 1. The process of solid reducing ores which includes feeding the ore to a preheatin c linder While maintaining a slightly oxidizing atmosphere inthe feed end thereof and a nonlore into a reducing'cylinder,

oxidizing or reducing atmosphere at the discharge end thereof, in discharging the heated in introducing a reducing agent thereto, and in introducing a stream of fuel and air, the air being-isolated from the charge being reduced by said fuel.

2. The recess of solid reducing ores which Y includes ceding the ore to a preheating cylinder, in discharging the heated ore into a reducing cylinder, in introducing a reducing agent therein, and in introducing a stream of air surrounded by a hollow body of fuel whereby the material being reduced is shielded from said air.

I In witness whereof, I'have hereunto signed my name.

JOHN WILLIAM HORNSEY.

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