US1279181A - Apparatus for reducing ores. - Google Patents

Description

H. N. TRACY. APPARATUS FOR REDUCING ORES. APPLICATION FILED MAR. l. 1-941,

Patented Sept. 17, 1918.v

' 2 SHEETS-SHEETL H. N. TRACY. APPARATUS FOR ne'nucma ORES,

APPLICATWN FILED MAR. I. I9l7.

Patented Sept. 111918.

2$HEETS-SHE'EI 2.

UNITED STATES rATENT OFFICE HARMON N. TRACY, OF LOS. ANGELES, CALIFORNIA.

APPARATUS FOR REDUCING ORES.

Specification of Letters Pateab t,

Patented Sept. 17, 11918.

Continuation of application Serial No. 23,548, filed April 24, 191%. This notification filed Mai-eh 1. 1917 Serial No. 151,629. l

To all Hi/t0!!! it may oneern:

Be it. known that I. l-zlannou 1 TntmY, a. eitizenot' the l nited State-s, residing at Los Angeles. in the county o'l. Los Angeles. State of California, have invented newand useful improvements in Apparatus for Reducing Ores, of whiehf the following is a specification.

This invention relates to apparatus for reducing ores; and the object of this invention is to provide an improved apparatus of the general eha'raeter shown in my applira tion to. N. 23.5%. tiled '.-\pril Z-l. 1915. on apparatus for redueinoores, and in my up plieation S. N. 141.820. filed January 1.1, 1917, on apparatus for reducing; ores: and. to provide an improved apparatus for carrying on that proeess for redueing ores explained in my applieation S. N. 136,645, liled lhseeu'lller 12-5. 1916. This application isa eontinuatirm in part of my said application h. X. 23.548; and whereas in my said applieutionS. 141.820, 1 claim those tern tures oi my apparatus that. refer partieularly to the shape. formation. etta, of the ore reducing stack. the introduetion of reducing agent, ete. in this present appliezu t'ion l earry on and speeitieally elaim those matters that. in my former upplienlioii S. N. 23.548 referred pa ticularly to combination of the stack \vithfthe. eooliag chamber and various other subsidiaryparts. And, further. .l herein.explaiu and elaim eertain improvementsin the apparatus over that shown in said application; S. N. 23.548. My present invention will be best understood from the following[detailed deseription of my improved and preferred form of apparatus. For this purpose reference. is had to the aeeompanying drawings, in which: l igurel is a vertical section show ing my improved apparatus; Fig. 2 is a (rose seetion taken on linen- 2 of Fig. 1; Fig. 3 i 'a vertieal section taken on line 2i.--l on Fi". lpand Fitz. l is anenlarged seetion taken as indicated by line 4 on Fig: 1. l

in the drawings I have shown a relatively long and narrow vertical ore stack 10. The stack is u'tade slightly larger at the hottonr .thim at the top in order to faei'litate the free passage of ore. downwardly therethrough wit hout ehoking. It-is one of the features of my invention that the ore passes through the stack 1Q under gravitational influence being; treated as herein provided. physically expand: and some ores become past tendingto elo r and choke it there are any eonstrietious in the stack.

1 provide a means for heating the ore \vhieh' is delivered to the upper end of the stack and I. prefer to heat theore use-lose to the upper end ol the stack as possible and to deliver the ore .direetly into the stack with the least, loss of heat. Preferably, for this purpose-I provide a revolving roasting drum ll of any preferred design. the diseharee end ll oi? the drum projecting into the ut per end 1t) ot' the stark. The drumis placed at a suitable incline so that ore fed into its upper end 11" froiuthe feed spout 12 will pass dou'n vardly through the drum.

A turnaee or burner apparatus 13 supplies heat to the roasting drum. said burner apparatus preierablj being in the form shown 1 in Fig. 1. and embodying alluid buruerlt, for gas or liquids. discharging into a conieal member L" as illustrated, air being drawn into this menrber around the flame, as indicated inthe drawings. tontrol of the burner is had by valve 16 or any other suitable means. The fian ie irLthe conical member 1.5 discharges into a furnaee ehatnher 24: which 'mayliave 011G101 more cross walls ol?.briek eheekerwvork; as indicated at i 35., From this furnace ehamber 24 the flame.

discharges aeross the upper end 10 of the stack into the heatingz and roasting drum 11. The air for the furnace may be drawn in through a tjaeketflti surrounding the outer part of the furnace structure, the air passing over the exterior part of the furnace and thereby being preliminarily heated; and the amount of air may be controlled by any suitable means. as by a damper located at; 9.7. which is of the type found in U. S

Patent 246.606. A draft stackis shown at 17 connecting-with the upperend of the. roasting drum" 11; The spout leadsiftimn.

any suitable bin 18 and the feed of ore is controlled by a revolving roller 19 0 Jerated by motor 20, which motor i contro led by a controller 21 on the switch board 22. Switch board 22 is mounted in a convenient position on the platform 23, said platform being preferably supported at the upper end of the stack. As hereinafter explained, the operation of my apparatus is under control of a single man on the platform 23.

The ends of the drum 11 preferably p'roject into the upper end 10 of the stack 10 and into the part 17" of the draft stack 17 and the drum ll-is provided with joint closure rings 11 of any suitable heat resistant material bearing against stationary flanges 29 on the parts 10 and 17, The rings 11 may be of asbestos or the like and are made to slip, more or'less tightly, on'the drum 11. As the drum expands longitudinally with the heat, the rings are shoved back from the ends of the drum and remain in position to bear against the flanges whenever the drum is heated to working temperature.

The drum 11 and furnace 1.3 not only perform the function of heating the ore directly prior to its delivery to the upper end 10 'of the stack 10, but also perform the function of roasting and oxidizing the ores which must preferably be changed to oxids before they are reduced in the reducing stack 10. However the ores are delivered to the drum 11, it will be presumed (for the purpose of this specification) that they are delivered to the upper end'of the reducing stack'in the form of oxids and the oxidized ores are discharged into the upper end of the reducing stack in suitably heated condition. The temperature of the ores is governed by conditions hereinafter stated. But for the certain ores, where sulfur is present, I may or "may not oxidize; I may see to it that-no excess air is present in the roasting At the lower end of the stack I provide 7 an'accumulatinf cooling chamber 30 of suit- .able i'oapacity r holding such a quantity ofreduced'products that coolin can be effactually carried out before the nal product is taken out to atmosphere; that IS, coolingto-a temperature belowthe point of oxida tionz. The cooling chamber 30 is at least as large as, and preferably larger than, the

stack in'horizontal section;.so that no im- 58'1" pediment is-oifered to the hot ore passing downwardly into the cooling chamber. In fact the coolingchamber may be described as a preferably enlarged lower extension or continuation of the stack. After the reduced ores are cooled they may then be removed from the cooling chamber through a constricted opening, there being, 'then no special tendency to clog or choke; I refer to arrange the cooling means as in mated 'in' the drawings comprising a numberof transverse tubes 31 and 31 rising toward the center as shown at 31, or may extend straight across the chamber as shown at 31. The inclined tubes aid in the even distribution of the material over the whole chamber 30. I prefer to make at least the upper rows of tubes in this shape. At one end of the tubes I may employ a blower fan 32 of any preferred design to provide a forced draft through the tubes; and the other end of the tubes may communicate with a chamber from which a draft stack 34 arises. This draft stack extends upwardly around the central reducing stack; the natural draft thcrethrough may be utilized without the fan to draw air through the cooling tube; and the hot air passing upwardly through the draft stack aids materially in keeping the reducing stack at proper temperature and in keeping the ores at or near their original temperature as they move down the column; forming an insulation zone around the reduction stack. The ends of some of the uppermost tubes 31, the ones which are at the highest temperature, may connect with a draft pipe 35 which extends upwardly and discharges into .the air jacket 26 of furnace 13. The air thus delivered to the furnace v ing in the system and not being lost.

At the lower end of the cooling chamber 30 I place a suitable discharge conveyer 40 operated by motor 41- controlled b suitable controller 39 on switch board 22. apparatus is in operation the attendant on the platform 23 has full control of the introduction andwithdrawal of ore to and from the stack 10; and by regulating the intro-- duction and withdrawal he also regulates the rain of How of ore through the stack, and thus regulates the time period for passage of ore through the stack and through the reduction zone; this time period being dependent upon the time element of the reducing'action; and this time per (i also dean my pending, in any given lant, orf ridiiferent classes of ores, on t e time ele ents of heating, oxidizin and cooling. T e introduction and wit drawal are so r that, withthe pro er rate of flow, t e stack 10 is kept constant y full of ore which moves downwardly under-the influence o'f gravitw tion at a uniform rate, movin downwardly an on downe wardly out of-the reduction zone into into.- the reduction. zone and ulated fairly equally from all cooling chamber below, and thence out through the conveyor 40 into any suitable conveying means or storage bins or .the like. The conveyor 40 may preferably be a belt or link chain conveyor running over drums 42, within an inclosing casing 43. This casing has a sloping perforated upper wall 4L4 having spaced openings 45 through which the cooled reduced ore passes onto the belt conveyor. It will be noted that the openings are situated at progressively greaterheights above the belt (in the direction of progress of the belt), so that at each openinga certain restricted amount of material will be taken out; and thus material is removed parts of the cooling chamber. The cooling chamber has lateral sloping bottom walls, as shown at 46, sloping down to the part 44:.

The re-agcnt employed for reduction may be varied to suit particular requirements; I have preferred to show and describe herein a means for introducing hydro-carbon, coal or water gas or the like to the central parts of the reduction stack 10. I may employ a holder or tank 50 into which the prepared gas is passed and from which the gas is taken by-a suitable con'ipressor or'blower 51 and forced through the pipe'52 to the distribution pipes 53. ()r the gas may be supplied under proper pressure and temperature and .in suitable quantity from any convenient source; as, for instance, direct from a gas producer of any kind. I prefer to heat the reducing agent, which may be done by uti' lining heat from the furnace (and therefore also from the cooling ores, because, as herein explained, heat from the cooling ores is conducted to the furnace). This is done by passing the gas through a coil 52 surrounding the furnace chamber 24, embedded in the furnace walls. A branch pipe 52" leads from pipe 52 to the C011 52, and flllOlThEzPlJlPfi 52 leads back to a pipe 52 and is controlled byvalve 52. .A valve 58' is placed on pipe 52 between its points of connection with pipes 52" and 52. By proper manipulation of these valves the gas may either pass directly from pipe 52 into the distributing pipes 54, or may pass first through coil 52, or may be divided and pass both ways. The gaseous reagent thus is heated with heat that would otherwise be lost by conduction and radiation. l-lcating the reducing agent obviates the necessity of heating the ore to an excessive temperature and enables me to operate the furnace 1.5 at the temperature required only to give the ore at the top of the stacka ten'iperature approximately, or-

ore at the point of introductipn and necessitates ori inal heating to la higher temperature, wit consequent inefliciency. Consider:

1ng the column of' ore and material as a whole from itsupper end to its lower end at the bottom of cooling chamber 30, the pipes 53 are preferably arranged somewhat above of gas supplied may be regulated and controlled by controlling the compressor driving motor 56 from the controller 57 on switch board 22. Proper pressure is maintained on the gas to cause its distribution through the ore in the'reducing zone at the central portions of the stack and to cause displacement and exclusion of the atmosphere. In actual operation the pressure required on the reducing gas to diffuse it throughout the rcducting zone is sufiicient to cause some unused gas to pass-down, along with the gaseous products of reduction; into the lower part of the stack and the cooling chamber. This mixture of gases is discharged along with the reduced ore at the discharge conveyer 40; and the gases are then caught in a hood 70 (or are separated from the ore by any convenient means) and are conducted through a pipe 71 to thefurnace where the unused portions are burnt as fuel. It will be understood that at all points of the rohunn of ore, from top to bottom, there is a gascoi-is pressure greater than atmospheric pressure; and this pressure effectually prevents entrance of atmospheric air at 40. The

casing J-i surrounds the conveyor 40 and is made to form an effective gas ight hood l3 to the upper part of which the hood 70 connccts. it will be noted that the ore discharge opening 4.3" is well below the hood 70, so

that no gas may escape; and this not only makes for efficiency but also for preventing the discharge of the gases around the stack where they are dangerous to the wm'lnucn.

The size of pipe 71 is such as to carry off the gases by-the draft of the furnace on pipe 71 and pipe is of sufficient size. with relation to the sizes of the pipes 31 which communicate therewith, to carry o'li' the air from those pipes.

The amount of gas to be supplied musl e suflicient to reduce the ore within the time period taken for the ore to pass vertically through the reduction zone. The rc-.

' comes filled with zone, and the metal is thus cooled in'the' no great variations tion; and the operator keeps the tcmperw hire of the ore at the most efiicicnt point, that is, at that temperature atwvhich reduc tion will most eiliciently take place. To enable an accurate control of the tempera -ture I may provide pyrometers having in- (33 on switch board 22. The

dicators 62 and operator can accurately control the temperature so as to obtain the proper temperature at and in the reduction zone; whether the total reduction action, including the breaking up of the oxids and the combination of their oxygen with the reducing agent, is exothermic or endothermic in its nature. In the one case the ore above the reduction zone is further heated by the surplus of heat arising from an exothermic action; while in the other a surplus of heat must be supplied from the furnace 13. The. outward spread of the reducing gas in the relatively narrow stack, drives out and displaces atmospheric air and thus excludes free oxygen entirely from-theclreducing zone an from the whole stack. When the apparatus is in full operation, the cooling chamber begases from the reduction presence of a non-oxidizing gas.

In my process there is a continuous treatment of the ore, embodying a continuous step of heating, roasting or oxidatiom fob owed by a continuous step of reduction in the manner described, followed by continu' ous cooling. As herein explained, one of the particular features of my method is the reduction step, wherein I form a constant, continuous column of preheated ore and form within that column-a zone throughout which a reducing agent is distributed under pressure suflicient to permeate the column and to displace and exclude atmospheric air.

It is a feature of operation that this column is not constricted at any point and that it gradually and uniformly expands from top to bottom. My method involves the use of no excessively high temperatures, and of of temperature. In fact, the temperatures throughout my method are very close to the total average, and the average temperature is fairly low. The ores are initially heated to no higher point than necessary to completely carry on the action of reduction; and, as hereinbefore stated, I preheat the reducing agent for this purose. Introduction of hot gas, rather than cold, has the effect of keeping up the temperature of the downwardly'moving ore and of keeping the ore at the reaction'temperature longer-than would otherwise be possible. I keep as much'heat as possible within the system of operations. .The air jacket surrounding the stack carries heat from the cooling reduced ores to' theore column, ma-

terially preventing loss of heat from the ores assing downwardly in the column. Heat is also conveyed from the cooling ores to the roasting surface, and thus conveys. heat to the ores at the point of preheating.

Having described a preferred form of my invention, I claim:

1. Ore reducing apparatus, embodying a relative? long and narrow-vertical stack substan ially unobstructed and free from constrictions from end end so that ore may move 'therethrough under gravitational action, means for heating ore at the-upper end of the stack and for introducing the heated ore to the upper end of the stack, 1neans'fo r withdrawing ore from the lower end of the stack, means to introduce afluid reducing agent tothe stack and ore col umn near its central portion, means at the lower end of the stack to cool the ore, and means for transferring heat from the cooling ore to the ore being heated.

2. Ore reducing apparatus, embodying a. relatively long and narrow vertical stack substantially unobstructed and free from constrictions from end to end so that ore may move therethrough under gravitational action, means for heating ore at the upper end of the stack and for introducing the heated ore to the upper end of the stack, means for withdrawing ore from the lower end of the stack, means to-introduce a fluid reducing agent to the stack and ore col-' umn near its central portion, said stack having at its lower end a cooli g chamber of larger size than the .tack and the stack discharging into the cooling chamber without constriction.

3. Ore reducing apparatus, embodying a, relatively long and narrow vertical stack through which ore may gravitate, fuel'burn ing furnace means for heating the ore and delivering it into the upper end of the stack, means for withdrawing ore from the lower endof the stack, means to introduce a fluid reducing agent to the stack and ore column near its central portion, means at the oint of withdrawal of the ore to carry off t e gases withdrawn with the ore, and means to direct said gases-into the ore heatin furnace. 4

Ore reducing apparatus, embodying'a relatively long and narrow vertical "stack through which ore may ravitate, means forheating the ore and de ivering' it into upper end of the stack,..means for withdrawing ore stack, means to introduce a fluid reducing agent to the stack and ore-columntherein cooling means for the ore at the lower end 0 the stack, and means to direct heat from the cooling ore to the ore-column in the stack.

5. The herein described method of reduc; ing ores, embodying first continuously heating the. ore, then continuously introducing the heatedore'intea vertical column of heatfrom the lower end of the ed ore of substantially uniform diameter from top to bottom and free from constrim tions, continuously introducin a reducing agent near the central part of t e column of ore and continuouslywithdrawi reduced ore at the bottom of the column, t e. rate of introduction and withdrawal of the ore being such as to keep the column of ore constant, continuously cooling the ore at the" bottom of the column, and transferring heat from the cooling ore to the ore being heated.

6. The herein described method of reducing ores, embodying first continuously heating the me, then continuously introducing the heated ore into a vertical column of heated ore of substantially uniform diameter from top to bottom and free from concoolin ore.

7. T he herein described method of reducing ores, embodyingfirst roasting the ore and heating it to a temperature approximately that of the reduction of its metal, then subjecting the ore to the action of a reducing agent, then cooling the ore, and in- "continuously;

sulatin the ore being reduced by a jacket of flui carrylng heat from the cooling ore.

8. The herein described method of treatingores, embodying first continuously heat- .ing the ore, then continuously introducing the'heated-ore into a vertical column of heated ore, continuously introducing a reducing agent near file central art of the column, Withdrawmg reduced ore at the bottom of the column, and withdrawing gases at the bottom of the column and burn- In'g those gasesto initially heat the ore.

9. The herein described method of reducing ores, embodying first continuously heating the ore to a temperature approximately that of the reduction action of its metal,"

then continuously gravitating the ore througlra vertical column of ore having no constrictions from top to bottom, continu ously introducing a fluid reducing agent at ordinary temperatures to the central part of the ore column under pressure to displace and exclude atmosphere, and continuously withdrawing reduced ore from the lower end of the'column, the introduction and Withdrawal of ore being regulated so as to keep the column constant.

. r In witness that I claimthe foregoing I have hereunto subscribed my name this 21st day of February, 1917.

HARMON N. TRACY.

Witnesses:

Enwoon H. BARKELEW, VIRGINIA Bnnmonn.

001110: of thin patent my be obtained for in cents each, by addressing the commissioner of Intent, Washington, 10,0.

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