US1174728A - Ore-reducing furnace. - Google Patents

Description

A. G. JONES.

y ORE REDUCING FURNACE. APPLlcArloN man MAR.26.1914. RENEwEn :AN.20.1916.

,1749723. Patenmd Mar. 7,1916.

2 SHEETS--SHEET I.

A. G. JONES.

ORE REDUCING FURNACE.

APPLICATION FILED MAR. 2s. 1914. RENEwED JAN.20.1916.

1.174,?28. l Patented Mar. 7, 1916.

2 SHEETS-SHEET 2.

Illllllllllllll sTATEs .PATENT OFFICE.-

ALBERT G. JONES, OF IRON-MOUNTAIN, MICIGAN, ASSIGNOR TO' NEW METALS- PROCESS COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

onu-REDUCING FURNACE.

Specification of Letters Patent.

Patented Mar. a, i916.

Application led March 26, 1914, Serial No. 827,357. Renewed January 20, 1916. Serial No. 73,177.

To all whom t may concern:

Be it known that I, ALBERT G. JONES, a citizen of the United States, residing at Iron Mountain, in the county of Dickinson and State of Michigan, have invented a new and useful OrefReducing Furnace, of which the following isa specification.

This inventionV pertains particularly to furnacesadapted to the purpose of redu ing metal oxids and carbonates to enable the metal to'be separated.

The vprimary object is to provide a furnace which is well adapted to metallize 'ores at a very low cost and produce the metals in practically pure form.

The invention is illustrated in its preferred embodiment in the accompanying drawings, in which- Figure l represents a broken elevational view of a furnace embodying the invention; Fig. 2, an enlarged vertical sectional view of the same; and Fig. 3, a broken sectional View illustrating'a slight modification.

In the embodiment illustrated, the invention comprises a de-oxidizing chamber A in which the ore is reduced t0 a metallic state; a pre-heating device B'wh'erein the (le-oxidizing gases produced in the furnace are ,consumed and utilized in pre-heating the ore and solid fuel as they pass to the furnace; and a chimney or stack C through which the products of combustion are dis charged from the pre-heater B.v The ore and fuel may .be-fed to the pre-.heater B from a hopper l'having an inclined chute 2 which extends through the chimney and serves to discharge the materials' into the upper end of the pre-heater. p

The pre-heater.. preferably comprises a cylinder mounted on rollers 3 and adapted to be slowly rotated by any suitable means (not shown). In the case of ar furnace having a capacity ofapproximately 100 tons per day, such as would be afforded by a deoxidizing chamber having a diameter of approximately 2O feet and otherwise properly proportioned. it would be desirable to exn ploy a pre-heating tube of approximately 8 feet in diameter and 120 feet in length. The pre-heating tube B should be provided with suitable refractory walls towithstand a heat of at least 2000O F. The pre-heated ore and fuel, are discharged through an elbow or hood'e. into a hopper 5 fitted with also be pre-heated if .a slide or closure 6 which may be with-v nace.

The chamber A is preferably of circular form and-has the base-portion 5 provided with a downwardly-tapering inner wall 5a, and has the semi-spherical upper wall 5". At the junction of the upper and lower portions of the furnace is an annular bustlechamber or bustle-pipe 7 into which the gases pass through openings 7a. Communieating with the bustle-pipe 7 is an outlet flue 8' which communicates with the lower end of the pre-heater B, the flue 8 preferably extending thrpugh the elbow 4. The lower portion of the chamber A should not be contracted sufficiently to cause choking, however. l

Air is admitted to the upper portion of the chamber A through a twyer or twyers 9 fitted with any suitable air-regulating valve l0. The twyers 9 should be adapted to admit sufficient air to provide a de-oxidizing gas', but the air admission should be so controlled-` as to prevent complete combustion Within the furnace. In a furnace of the size indicated above, it is desirable to provide a plurality of twyers. For illustration, one may use eight twyers, each having a diameter of approximately twenty four inches. the twyers 9 by'natural draft, but pressure may be employed if desired. The air may desired.

Through the upper inclined portion of the Elue 8 extends a tWyer 11 fitted with an airadmission valve 12. The twyer A11 should be of sufficient capacity to admit enough air to the pre-heater B to complete the combustion of the inflammable gases which pass to the pre-heating chamber through the flue 8. It is desirable t0 burn the combustible gases and utilize the heat therefrom for pre-heating, but a neutral or non-oxidizing medium l shuld be maintained in the pre-heater. In

other words, the best results are obtained by The air preferably passes through supplying to the pre-heater air sufficient to l burn the gases, but with no free oxygen present totattack the solid fuel.

The neck-portion of the furnace may be provided with pipes 13 through which Water may be circulated for cooling purposes.

The upper portion of the furnace may be 1 Vide a de-oxidizing flame.

fitted with removable plugs 14 received by plpkeopenings 15V. In the base-portion of t e bers 16; and a discharge-slide 17, which may be hydraulically actua-ted, is also provided. A cone 18 may serve to spread the burden; or any suitable means may be employed to insure proper drawing of the air through the burden. p

The stack C should be of ample dimensions to give the desired draft, say, of a diameter of 8 feet The proportions for the stack and preheater which have been given are amplein fact larger than are necessary.

In the operation of the improved furnace,

the ore and the bulk of the solid fuel (in dis-.

tilled form) are fed through the hopper 1 to the slowly-revolving pre-heater B down which' the material gravitates and fills the furnace, the slide 6 being open. The upper portion of the mixed ore and fuel in the furnace assumes a position somewhat asindicated by the dotted lines 19. The slide 6 is then closedand the furnace -fired at the base, which can be done by withdrawing the slide 17. The products of combustion pass up through the flue 8 and are discharged into the pre-heater. Suflicient air is admitted through the twyers 9 to prop Sufficient 'air is admitted through the twyer 11 to complete the combustion of the de-oxidizing gas which passes to the pre-heater through the flue 8. In this manner the temperature in the lower portion of the tube B is raised to at least 2000O F. The temperature in the tube B gradually decreases as the stack is approached, and at the upper end of the tube the temperature need not .exceed approximately 500 F.

It is preferred to feed a mixture of ore and either coke or charcoal to the furnace through the pre-heater B in accordance with the process described in the application of AlbertG. Jones, No. 827,358, filed of even date herewith, using such an excess of the coke or charcoal in lump or block form as will serve to hold of the ore separated or practically isolated from each other; and it is preferred to charge directly into the upper portion of the furnace, `as through a; door 20, a relatively small proportion of fresh carbonaceous fuel adapted to supply hydrocarbons and hydroen was as for instance wood or coal.

4In charging the furnace in the first instance through the use either Wood or coal, preferably in block or lump form, mixed with the ore; and when the furnace is fired, coke or charcoal will be produced, which Will be discharged with the metallized ore. Thereafter, the coke or charcoal may bev separated from the metallized ore and re-charged with fresh ore urnace are provided discharge-cham-- and a height of l150`lfeet. p

portions or lump-groups pre-heater B, one may' into the pre-heater, and a relatively small amount of fresh coal -or wood may be charged into the furnace from time to time through the charging-door 20.

In treating an ore composed mainly of iron oxid, a suitable mixture of coke and ore is afforded by using approximately 400 poun'ds of coke to 250 pounds of ore, supplemented by 100 pounds of coal introduced through the charging-door 20. The coke is used over and over again until it is finally consumed, the fresh coal introduced through the door 20 serving continuously to replenish the supply of coke.

It is' desirable not only to cle-oxidize the metal oxids, but also to set or fix the metals, so that reoxidation will not occur. This is accomplished by metallizing the ore and globing or globularizing the metal by producing in the furnace A a considerable excess of heat over that required for deoxidizing purposes, so that the metal particles which vare grouped close to each other will fuse and form themselves into globular shapes, but without producing a molten bath. The materials are discharged in solid form, but in separate lumps or'pieces, at the bottom of the furnace.

Copper oxids and copper carbonates are amenable to the same treatment but require somewhat less fuel, and the treatment may be carried on at, a somewhat lower temperature. In operating the furnace on ores of the character above referred to, the temperature in the upper portion of the furnace should be in excess of 2000O F. and preferably ranging as high as 3000o F. or higher. The temperature in the vicinity of the outlets 7 a would be lower, but preferably should not fall Ymuch below 20000 F. It has been found that when a sufficiently intense heat is maintained the carbon dioxid which is formed in the vicinity of the twyers 9 Vwill give up a portion of its oxygen to 'the carbon, forming carbon mon-oxid, which, in turn, robs the metal oxids yof their oxygen. Under these conditions, there is a rapid interchange of oxygen, vand the de-oxidizing of the metal oxids is rapidly effected. Such portionsv of the metals as become globed in masses are readily separated from the fuel when the fuel is discharged from the furnace. On the other hand, myriade of tiny globules of metal may adhere to the coke and be re-charged therewith into the prefheater, and during a second journey through the furnace, these small metal globules carried by the coke coalesce with other metal globules, formking globules of' tangible size which are readily recoverable.

In the case of zinc and lead, vaporization takes place at a temperature of approxi mately 2200o F., and a condenser is necessary to effect recovery. In dealing with lead and zinc oxids and carbonates, the furnace may nation with a base-portion provided-with be operated at a somewhat lower temperature than is ordinarily desirable when deal,- ing with iron and copper ores.

It may be added that Vowing to the fact that the ore and fuel-pile in the'furnace is of relatively small height and wide base, it is possible to operate the furnace by natural draft, thus effecting a very great economy;

and the improved furnace may be so operated as to produce practically perfect combustion before the gases are discharged from the pre-heater B into the stack. Ity will be understood, of course, that the hydrogen and hydro-carbons distilled from such fresh fuel as is introduced through the door Q0 will aid in the de-oxidizing process.

While it is unnecessary to use an air-blast in connection with the improved furnace, it is nevertheless possible to use the air-blast; and Where so used, comparatively small power would be required, owing to the low column of ore through which the gases must of necessity pass. In Fig. 3 is shown a modification in which the hopper 5 is replaced by a charging-neck 5a equippedwith bells 5b of knownV form, beneath which isa twyer 9a through which airis supplied from .a fan 9b; Such an arrangement may be used,

if desired, but natural `draft will suffice. The ue 8et corresponds with the flue 8, and the twyer 11a corresponds withth'e twyer 1l. y

In the furnacepillustrated, the diameter of the furnace is'QO feet, and the height of the furnace above the outlet ports?a is in the neighborhood of l0 feet. Such a furnace is adapted for operation with natural draft.

. The foregoing detailed description has been given for clearness of understandin only, and no unnecessary limitation shoul bel understood therefrom, but the appended claims should be construed as broadly as permissible in view of the prior art.

lVhat I regard as new and desire to secure by Letters Patent is- 1. In an ore-reducing furnace, the combimeans for discharging .ore-and solid fuel, an upper portion provided with means for charging ore and fuel thereinto, means Afor supplying air to the upper portion of the.

furnace, andan outlet gas iiue communicating with the middle portion of the furnace.

2. In an ore-reducing furnace, the com bination of a de-oXidizing-chamber provided at its upper portionv with means for introf ducing ore and fuel thereinto, a pre-heater having its lower portion adapted to deliver pre-heated ore and fuel to thede-oxidizingchamber, air-admission means communicating with theY upper vportion of the de-oxidizing-chamber, and a gas flue connected with the median portion of thede-oxidizingi ,chamber and communicating with the lower portion of the pre-heater.

3. In an ore-reducing furnace, the combination of a de-oxidizing-chamberprovided at its upper portion with means for introducing ore and fuel thereinto, a pre-heater having its lower portion adapted to deliver preheated ore and fuel to the de-oXidizingchamber, air-admission means communicating with the upper portion of the de-oXidizing-chamber, an outlet-gas flue leading from the de-oxidizing chamber some distance below the airsadmission means and communicating with the lower portion of the preheater, and means -for supplying air to the lower portion of the preheater.

4. In an ore-reducing furnace, the combination of a de-oXidizing-chamber having an enlarged central portion and a gas flue leading therefrom,a pre-heating tube having its lower end disposed above said de-oXidizingchamber, a closure interposed between the pre-heating tube and the de-oXidizing chamber, means Ifor supplying air to the upper portion of the de-oXidizing-chamber, said gas flue serving to discharge gas into the lower end 'of the pre-heating tube, means for admitting air to the lower end of the preheating tube, and a smoke-stack connected with the upper end of the pre-heat- -ing tube.

5. In an ore-reducing furnace, the combination ofy a down-draft de-oXidizing-chamber, an inclined heating-tube adapted to deliver pre-heated ore and fuel to the upper` portion of'said chamber,'means for supplying air to the upper portion of said chamber, a` gas iue communicating with said chamber near its median portion andserving to conduct gas to the lower portion ofV the pre-heating tube, and means for admitting air to the lower portion of the pre-heating tube.

6. In an ore-reducing furnace, the combination of a down-draft de-oXidizing-chamber, an inclined preheatingftube adapted to deliver pre-heated ore and fuel to the upper portion of said chamber, meansl for supplying air to the upper portion of said chamber, a gas flue communicating with said chamber near its median portion and serving 'to conduct gas to .the lower portion of the preheating tube, a closure interposed between the pre-heating tube and said chamber, and means connected with the upper portion ofthe preheating chamberl -through which fresh fuel may be charged.

7. In an ore-reducing furnace, the combinati-on of a down-draft de-oxidizing-'chamber having a relatively large central portion, a gas flue leading from said central portion, an inclined pre-heating tube having its lower end adapted to deliver pre-heated ore and fuel to the upper portion of said chamber, said flue serving to deliver gaseous fuel to the lower portion of said pre-heating tube, and means for supplying air. to the upper portion of said deoxidizingchamber.

8. In an ore-reducing furnace, the com-A .communicating with the lower portion thereof, a down-draft de-oXidizing-chamber beneath said elbow provided with a gas flue which extends through 'said elbow and serves to deliver gaseous fuel to saidy preheating tube, a closure interposed between said elbow and said. de-oXidizing-chamber,

and air-admission means connected with the v upper portion of the de-oXidizing-chamber.

10. In an ore-reducing furnace, the combination of an inclined pre-heating tube, an'

elbow communicating with the lower portion thereof, ,adown-draft de-oxidizingchamber beneath said elbow provided with a gas flue which extends through said elbow and serves to deliver gaseous fuel to said pre-heating tube, a closure interposed between said elbow and said de-oxidizingchamber, air-admission means connected with the upper, portion of the de-oXidizingchamber, and a twyer extending through the upper portion 'of said lueand serving todeliver air to the lower portion of said pre-heating tube.

1l. In an ore-reducing furnace, the combination of a down-draft (le-oxidizingchamber of relatively large horizontal circumference at its median `portion and relatively small height above said median portion, a gas flue communicating with the median portion of said de-oXidi'zing-cham-` ber, an inclined pre-heating tube having its lower portion disposed to deliver preheated ore and fuel to the upper portion of the de-oXidizin'g-chamber, and means for regulating the admission of air to the upper portion 'of the .de-oXidizing-chamber.

12. In an ore-reducing furnace, the combination fof a` down-draft cle-oxidizingchamber having a contracted upper end, an enlarged median portion, and a reduced lower portion, said chamber formed with a bustle-pipe at its median portion, a gas flue leading -from said'bustle-pipe, an'inclined pre-heating tube adapted to deliver pre-heated ore and fuel to the upper portion of said chamber, and with the lower endof which said gas-flue. communicates, an elbow connecting the lower4 portion of the pre-heating tube with the upper, portirarse tion of said chamber, a closure separating the pre-heating chamber from said elbow, means for admitting air to said chamber below said closure, and means for supplying air tol the lower portion ofthe preheating tube.

13. In an ore-reducing furnace, the rcombination of a relatively low, large-area deoXidizing-chamber equipped at its upper portion with air-admission means, a relatively long inclined pre-heating tube having `its lower end disposed to deliver preheated ore and 'fuel to said chamber, and a gas-flue connecting said chambers below said air-'admission means 'with the lower portion of said pre-heating tube. y

14. In an ore-reducing furnace, the combination of a relatively low, large-area deoXidizing-chamber equipped at its upper portion with air-admission means, a relatively long inclined pre-heating tube having its lower end disposed to deliver preheated ore and fuel to said chamber, a gasflue connecting said chamber with the lower portion of said pre-heating tube, an elbow connecting the lower end of said pre-heating tube with 'the upper portion of said chamber, and a closure for the upper portion lof said chamber.

l5. In an ore-reducing furnace, the combination of a relatively low, large-area deoXidiZing-chamber equipped at its upper portion with air-admission means, a relatively long inclined pre-heating tube having its lower end disposed to deliver preheated ore and fuel to said chamber, a gas` flue connecting said chamber with the lower portion of said pre-heating tube, an elbow connecting the lower end of said pre-heating tube with the upper portion of said chamber, a closure for the upper portion of said chamber,- and means connected with the upper portieriy of said chamber for enabling fresh solid fuel to be introduced into the chamber.

16. In an ore-reducing furnace, the combination of a relatively large pre-heating device through which ore and solid fuel may be fed slowly, a relatively low upright dre-oxidizing chamber having 'its upper portion communicating with said pre-heating device,gmeans for supplying air to the ore and fuel bodv in the de-oxidizing-chamber,

and means for supplying ain to the pre-- heating device to burn the combustible gases passing thereto from the rie-oxidizingchamber.

17. In an ore-reducing furnace, the combination of a pre-heatingdevice of relatively large dimensions, an upright ie-oxidizing chamber of relatively small height and large area, said de-oxidizing chamber having communication at its upper portion wit said pre-heating device, means for suppl` ing air to the interior of the ore and fuel body airlines within said de-oXidizing-chamber, and means for supplying air to said pre-heating device in such quantity as to consume the combustible gases therein Without attacking the solid fuel.

18. In an ore-reducing furnace, the combination -of a relatively large-dimensioned, inclined pre-heating tube through which ore and solid fuel may be fed slowly, a de-oXidizing-chamber communicating with the lower end of said pre-heating tube, means for supplying air to the lower portion of said pre-heating tube in such quantity as to burn the combustible gases therein without attacking the solid fuel, and natural-draft means for supplying air within the ore and fuel body in said de-oXidizing-chamber in sufficient-quantity to maintain a hot de-oXidizing and metal-fusing and globing temperature in said de-oXidizing-chamber.

19'. In an ore-reducing furnace, the combination of a relatively large-dimensioned, inclined prerheating tube through which ore and solid fuel may be fed slowly, a de-oxidizing-chamber communicating with the lower end of said pre-heating tube, natural draft means for supplying air to the lower portion of said pre-heating tube in such quantity as to burn the combustible gases therein without attacking the solid fuel, natural-draft means for supplying air within the air and fuel body in said deoXidizing-chamber in sufficient quantity to maintain a hot de-oxidizing and metal-fusing and globing temperature in said deoXidiZing-chamber, and a smoke-stack communicating with the upper end of said preheating tube.

20. In an ore-reducing furnace, the combination of a relatively large-dimensioned inclined pre-heating tube through which ore and solid fuel may be fed slowly, a smokestack communicating with the upper end thereof, a charging-device having a chute extending through said stack and adapted to deliver ore and fuel to said pre-heating tube, a relatively-low de-oXidiZing-chamber having a passage communicating with the lower end of the pre-heating tube through which combustible gases may pass, and twyers adapted to deliver air within the fuel and ore body in said de-oXidizing-chamber in suiiicient quantities to maintain a high de-oxidizing and 'metal-fusing temperature therein.

21. In an ore-reducing furnace, the combination of a. de-oxidizing chamber adapted to support a low stack of mixed ore and fuel, means for introducing an air supply into said stack in such quantity as to provide by the re-actions a metal-fusing and globing temperature in one zone and a cle-oxidizing medium in another zone, a preheating device adapted to supply pre-heated ore and fuel to said dez-oxidizing chamber to replenish said stack, said pre-heating device receiving the gases from said cle-oxidizing chamber after they have served the de-oX- idizing function, means for charging fresh fuel into said cle-oxidizing chamber, means for supplying air to said pre-heating device t0 burn the gases therein, and means for removing unburned fuel, gangue and metal in solid form from the bottom of the de-oxidizing chamber.

22. In an ore-reducing furnace, the combination of a cle-oxidizing chamber adapted to support a low stack of mixed ore and fuel, means for introducing an air supply into said stack in such quantity as to provide by the re-actions a metal-fusing and globing temperature in one zone and a de-oxidizing medium in another zone, a pre-heating device adapted to supply pre-heated ore and fuel to said de-oxidizing chamber to replenish said stack, said pre-heating device receiving the gases from said de-oxidiz'ing chamber after they have served the de-oX- idizing function, means for supplying air to said pre-heating device to burn the gases therein, and means for removing unburned fuel, gangue and metal in solid form from the bottom of the cle-oxidizing chamber.

ALBERT G. JONES.

In presence of NELLE B. DEARBORN, E. D. STEELE.

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