US1751736A - Apparatus for reducing oxides of metals - Google Patents

Description

March 25, 1930. J. w. HORNSEY APPARATUS FOR REDUCING OXIDES OF METALS Filed Sept. 8,

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APPARATUS FOR REDUCING OXIDES OF METALS Filed Sept. 8, 1926 3 Sheets-Sheet 2 ndc VA 43.43

March 25, 1930.

J. w. HORNSEY 1,751,736

APPARATUS FOR REDUCING OXIDES OF METALS Filed Sept 8, 1926 3 Sheets-Sheet 3 Patented Mar. 25, 1930 UNITED STATES PATEVINT OFFlCE "JOHN W. HORNSEY, OF OAKES-IN-NORTON, BY SHEFFIELD, ENGLAND, ASSIGNOR T0 GRANULAR IRON COMPANY, A CORPORATION OF MICHIGAN APPARATUS FOR REDUCING OXIDES 0F METALS Application fi1ed.September 8, 1926. Serial No. 134,287.

In a previous application No. 532,486, filed January 28, 1922, I have described a process of reducing iron ore to metallic iron without melting, by first heating the ore in a state of division to approximately the tempera 'ture of reaction, below the fusing point, and then mixing and agitating the heated ore with solid carbonaceous fuel also in a state of. division and finally cooling the product,- excluding air except as required for combustion; the operation being carried out in a succession of inclined rotating cylinders.

The present application is directed to certain improvements in the apparatus and method described, some of the features being useful in reducing not only iron ore, but also oxides of other metals, such as zinc, lead and copper ores, for example.

The accompanying drawings illustrate the apparatus.

Fig. 1 is a longitudinal section of practically the complete apparatus for bringing the ore through the several stages involved;

Fig. 2 is a cross-section of Fig. 1 on the line'2-2;

Fig. 3 is an enlarged detail of Fig. 2;

Figs. 4 and 5 are respectively sections on correspondingly numbered lines in Fig. 1;

Fig. 6 is a longitudinal section of a modified structure;

Fig. 7 is a cross-section approximately on the line 77 thereof.

Referring .to the drawing, the first cylinder or rotary drum 1 is slightly inclineddown ward at its right hand end and is open at its left end to a cross flue 2 which leads to a stack, the gases passing over a baflie 3 and the dust dropping into a bin 4 from which it is withdrawn as desired by opening a gate 5 in a chute 6. Sight holes 7 are provided as requiretl. The supports and means for rotating the cylinder are omitted for the sake of clearness. They may be of any usual or suitable construction. The upper end of the cylinder has a considerable play in the wall 8 of the entrance chamber and between these two parts a sub'stantially or approximately airtight seal indicated at!) is provided, which may also be of any usual or suitable construction. The sealing "rings are designed to allarge pieces. grating drop into a conveyor 23 which car-' 100 low considerable flexibility and are open at the bottom into a dust pocket 10 at the bottom of which is ascrew conveyor 11 for carrying off the dust.

A conveyor 12 of screw or similar type car- 65 ries ore-from an outside bin and dumps it into the upper end of the cylinder. At this point there are provided angular vanes 13 spirally arranged to pass the ore quickly forward and prevent congestion at the upper end near the delivery point of the conveyor 12.

The tube 1 is chiefly a pre-heater for the ore. The temperature at the upper end is comparatively low so that only a metal shell is necessary. The greater portion of the length, however, has a heat resistant lining 14 of suitable refractories. The entire cylinder may rest on rollers and be rotated by gearing. The gases from a reducing operation en ter the lower end of the cylinder. It S desirable to use these for heating. For this pur-. pose a stationary water cooled pipe 15, or a series of such pipes, enters the lower end of the cylinder and supplies air for combustion of the gases from the reducer. ordinarily finely divided. It is thoroughly dried in the upper end of the preheating cylinder. As the cylinder rotates, the divided ore is turned over frequently for exposure to the heatinggases and is at the same time 82 fed slowly down the incline. Y

The preheating cylinder has its lower end leading into a structure which is stationary,

and which serves to pass the ore to the reducing cylinder and to pass the reducing gas through a separate passage to the preheater. We may call this the transferring means. The end o'f'the preheating cylinder enters the end 16 of this structure withfree play therein to allow for distortion and movement.

An annular flexible seal 17 is provided as at the upper end and the dust discharges below into a pocket 18 at the bottom of which is a screw conevyor 19. At the underside of the fixed structure is a transverse chamber 20 into which the preheater discharges its dre. This has a man hole 21 at the side and a grating 22 for holdingvback any excessively Those which 'pass through the The ore is 75 heated ore.

ries them forwardto the upper end of 'the reducing cylinder 24. There are sight holes 25 at various points where the operation should be observed. The right hand portion 26 of the casing 16 is inclined downward as shown to the level of the conveyor 23. The opening in this part of the apparatus is practically of the same diameter as the preheater. It is through this opening that the gas passes from the reducer to the preheater. It may be ignited for complete combustion by burners at various points. One burner hole is shown at 27.

Alongside the ore conveyor 23 is a coal conveyor 28. Through this coal, also in a divided state, is conveyed to the upper of the reducing cylinder for admixture with the The coal conveyor may be water cooled in any usual way. It is important to have the ore conveyed hot. This would ordinarily weaken its conveyor structurally. I propose to strengthen it in the manner illustrated in Fig. 3. An outer steel shell 29 is embedded in the brickwork of the surrounding structure. It is lined with a loose fitting shell 30 within which is a metal tube 31 spaced by lugs from the tube 30 providing segmental spaces in which water is circulated to keep it tool and stiff... The inner tube 32 is made of metal adapted to resist high temperatures and is spaced by lugs on the bottom from the metal tube 31 to provide insulating spaces for air or other insulating medium. The conveyor is preferably of the screw type and made of metal especially adapted to resist high temperatures. This construction permits of the withdrawal of the conveyor from the outer shell 29 which is embedded in the brickwork. The ore conveyor is similarly carried loosely in a shell embedded in the brickwork. This conveyor and its water cooled supporting structure is not claimed herein asit forms the subject matter of my co-pending divisional application SerialNo. 348,066, filed March 18, 1929.

The upper end of the inclined reducing cylinder 24 is also arranged with a certain clearance in the end of the transfer structure 26, and the space closed by a flexible annular seal 33 with a dust pocket 34 at the bottom, carrying a screw conveyor. For further elimination of dust, the part 26 has a trans- The layer inder 24 it is to be cooled while guarding it substantially from excess of air.

The next cylinder 47 is the cooler and does not have to be lined with refractory material. Its upper end is provided with spiral angles or ribs 48 for preventing accumulation of the charge at this point. The junction with the structure 38 is protected by an annular seal 49 with a dust pocket 50 at the bottom.

And the open space at the end is provided with a supplementary dust pocket 51. Water distributors 52 in the form of troughs with serrated overflow edges are arranged above the middle portion of the cylinder, and the latter is provided with annular flanges or rings 53 and 54 to obstruct the flow of the water toward the ends of the cylinder. The water distributors should be in lengthwise sections fitting between gears or tires which may be provided around the cylinder.

At its lower end, the cooler is closed by a casing 55 of sheet metal with a man hole 56, and with sight holes 57 wherever desired, and with a flexible seal 58 discharging into a dust pocket 59. The cooled product runs out of the end of'the' cylinder 47 into a transverse trough 60 at the bottom of which is a screw conveyor 61 which empties into a discharge spout 62, Fig. 5.

By interposing stationary transferring structures between the several cylinders, the sealing of the meeting ends against admission of air and escape of dust is .much facilitated.

In Figs. 6 and 7, I have illustrated modifications in the design of the stationary structures at opposite ends of the reducer,

eliminating the screw conveyors for the charge which are shown in Fig. 1 and substituting inclined chutes. The lowerend of the preheater 1 is sealed in an opening at the top of a structure 63 in which is a man hole 64 and burner holes and sight holes as required. The structure 63 is a vertically extending chamber and has a sealed connection at the opposite side of its lower end with the rotary reducing cylinder 24. A metal chute 65 has its upper open end in line with the lower part of preheating cylinder 1 so as to receive the material therefrom and convey it to the lower end of the chute which extends into the reducing cylinder 24. The chute 65 may be made in sections and supported on and anchored to a brick pier or wall built into the chamber. The gas passes up from the reducer through the chamber on each side of the chute 65 and its supporting wall. The

dust falls on each side of the wall into a dust bin 66 at the bottom which has a sealed outlet and any usual means for removing the dust. I i

The coal is fed through a conveyor 28 similar to that described in connection with Fig. 1. The coal and the charge drop to gether into the upper end of the reducing cylinder The ends of the spiral coal con veyor and the ore chute may be water-cooled in various ways. The lines 67 illustrate diagrammatically water-cooling pipes extending to the ends of the chutes.

In this connection I have shown a different type of dust collector 68 for the sealing rings, which may be used in place of thearrangements shown in Fig. 1. At the bottom of the dust collector (see Fig. 7 are bells 69 and 70 mounted on levers which extend outside of the tube andby which the bells can be opened and closed one after theother so as to drop the dust without admitting air.

Fig. 7 shows most clearly the preferred shape of the lining of the reducing cylinder 24. The lining is formed at the entering end of the cylinder in ridges or steps 71 which are spirally arranged in a manner similar to the spirals 13 of Fig. 1 in order to pass the ore quickly forward to prevent congestion. near the delivery point of the chute 6'5.

At the lower end of the reducer in Fig. 6

is shown a transferring structure 72 with the usual sight holes and burner holesv therein. The bottom of the chamber is sha. ed to form an inclined chute 7 3, which is pre erably water-cooled. The chute may be lined with a metal tube 75 which extends down to .the lower portion of the upper end of the cooler47. Thereduced charge drops over the spilling rib. 37 and runs by gravity through the chute into the cooler. A man hole 76 is provided in the side of the transferring chamber. I

The stationary (and 63) between the preheating cyhnder and the reducing cylinder carry only the gases and these are out of contact with the air and coal in passing through the transfer structures. It is desirable to make the reducing cylinder 24 of somewhat larger diameter than the preheating .cyhnder 1. The stationary transfer structures between the two cylinders permit this without complication of the sealing means. The clear passage for the gas through the structure 63, Fig. 6, is larger than the passageway through the cooling cylinder 1. The gases will there-- i fore pass through the structure 63. comparatively slowly which will eflect a more complete separation of dust. The dust separatransferring structures 26- tion is also increased because of the extent of the vertical travel in the arrangement of Fig. 6. On the other hand, the cooling elfect 0n the gasesis greater in the structure of i to increase the extent of the dust separation at this point. I

Various modifications of the apparatus described may be made b those skilled in the art without departure i rom the invention as defined in the following claims.

What I claim is: P

1. An apparatus of the character described comprising an inclinedcylinder for feeding and treating the charge, an adjacent structure with relation to which said cylinder is rotated, the cylinder end having play in theadjacent structure, gas sealing means between said structure and the cylinder and means for collecting dust at the bottom of said sealing means. v

2. An apparatus ofthe character described comprising a pair of cylinders through which the charge is fed in succession and treated, which cylinders are approximately in line with each other and an intermediate stationary structure through which the charge passes from one cylinder to another and through which the gases pass in reverse direction, said intermediate-structure having two passages through which respectively the charge and the gases pass.

3. An apparatus of the character described comprising a pair of vessels through which the charge passes in succession and an intermediate structure having' two passageways through it one for the charge andanother for the gases. I

4. An apparatus of the characterdescribed comprising a pair of vessels through which the charge passes in succession and an intermediate structure having a passageway through it for the gases anda closed inclined chute for transferring the charge through one of said vesselsjtothe other by gravity.

5. An apparatus of the character described comprising a pair of rotating cylinders through which the charge is fed in succession and an intermediate stationary structure having a passageway for the gases and having an inclined closed chute for passing the charge by gravity from one cylmder to the next. v

6. An apparatus of the character described comprising a pair of cylinders of diflerent diameters through which the charge is fed in succession and treated and a stationary strucpassage through which the charge passes from one cylinder to another and a flue through which the gases pass in reverse direction.

' 7. An apparatus of the character described comprising a pair of cylinders of different diameters through which the charge is fed in succession and treated and an intermediate stationary structure through which the charge passes from one cylinder to another and through which the gases pass in reverse direction and gas sealing means between said structure and the respective cylinders.

8. An apparatus of the character described comprising cylinders through which the charge is fed in succession and treated, gas

sealing means between the ends of the cylinders and dust collecting means at the bottom of said gas sealing means.

9. An apparatus of the character described comprising cylinders through which the charge is fed in succession and treated, flexible gas sealing means between the ends of the cylinders and dust collecting means between said cylinders.

10. An apparatus of the character described comprising cylinders through which the charge is fed in succession and treated and dust collecting means between said cylinders.

11. An apparatus of the character described comprising a plurality of gas sealed rotating inclined Vessels through which the charge is fed and treated, stationary structures between them and dust collecting means operatively associated therewith.

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

JOHN w. HORNSEY.

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