US1838427A - Ore reduction - Google Patents

Description

Dec. 29, 1931. A. G. MCGREGQR I 1,838,427

' ORE REDUCTION I Filed March 28, 1929 4 Sheets-Sheet l Dec. 29, 1931. 7 AG, MCGREGOR v 1,838,427

ORE REDUCTION Filed March 28, 1929 4 Sheets-Sheet. 2

Dec. 29, 1931. A. G. MCGREGQR 1,838,427

ORE REDUCTION Filed March 28, 1929 4 sheets-sheet 5 Dec. 29, 1931. A. G M GfiEGQR ORE REDUCTION 4 Sheets-Sheet 4 Filed March 28, 1929 Patented Dec. 29, 1931 ALEXANDER G ANT rrreenneon onnonnon, lven-Am) :ORE REDUCTION "Application'filed March 28, 1929: "Seria-l' No; 350,605.

- This invention comprises improvements in ore reduction: and hasfor its object to provide a process and apparatus-for the reduction of ores particularly copper ores, which is suited A i for continuous operation upon a large scale and wherein thereverberatory furnace required'in-suoh operations is so supplied and operated that a high efficiency is secured,

temperaturelosses are reduced to a minimum the handling ofth'e: ore issimplified and caking together ofcalcined ore before delivery to tl'iereverberatory furnace is obviated.

In my previous 'United States application Serial No. 140,909, there is described an apparatus forthe smeltingof copper ores which coi'nprises reverberato-ry furnaces arranged below groups of roasting furnaces, and con nections for delivering calcined-ore from the roasters to the reverberatory furnace which comprise hoppers above the reverberatory furnace to which the ore is delivered and in which it remains pending delivery to the reverberatory furnace. One of the. difficulties of operation of such an appara- 'tus lies in the fact that the-calcined materialtends'to cake together andth'ereafter is difiicult to feed intothe furnace. -The'large calcine-hoppers employed moreover delivers thematerial into the 'furnacein large batches and the mass ofthecharge'fallingintothe furnace by gravitytends to'raise large quan tities of dust. In'the said prior apparatus the furnace was intendedto workinthe manner usual withrreverberatory furnacesr large charges of ore being delivered to the furnace and melted, the product removed and 'aifresh charge of ore thereafter-reduced. "-In other words, theoperationrwas periodicor cyclic and. .IlOiZCOIliZlDGOHS. In operating afurnace inithis fashion'the furnace iis liable to considcrable cool-in when afresh charge of-ore is introduced and the alternate -heating and cooling tend-to increase the fuel required.

'llheprcsent invention comprises features of a y aparatus which are hereinafter described and'which enable awfurnac'e. to be uniformly (:harged with o-re'aha plurality ofpoints dis tributed 9 along its length along each side of the furnace. Such means may comprisetwo main ore delivery pipes, one allocated-to each side of i the. furnace and a means to distribute the oretherefrom.v V v "The invention further comprises means. for ensuring" the 5 continuous supplyof calcine from the :roasters in the case where lonetor more of. the: roasters has to; be shut down, .ineans for diverting oresto other reverbera- .tory. furnaces where one of therreverberatony furnaces hasto be shut down endotherrfeatnres hereinafter described;

Tilheinvention further: c0mprises:a process of ore reduction,inacreveberatoryfurnace characterized by feeding the :ore to thG'EfllT- nace ,in small succesive batches sdel ivered rat different :poi-ntsrzalong the zreaction fzone of a .the furnace in rotation, keeping, the furnace continuouslyein operation .1 and. periodically removing matte and slag therefrom; 1 a" .The following. is a description hyxlway of example of plant constructed:in-accordance with 2th is invention' with reference to the eaccoinp anying drawings, in "WhlC-lI'Z Figure 1 is a section ofya partf'of'aacombined roasting and irewerberator-y smelting plant in accordance with thisiinventiomntaken upon the %line 15.1 of. Figure. :21;

. igurei2qis' a vertical section in a'zplane at "right; angles to? the" plane of :Figure 1 taken uponstherline 2,2of Figure 1:;

Figure '3 's a. diagrammatic plan :ofuthe plant upon-a smaller scale: than 'Figures 1 -andj2z; 5

Figure 4: is averticalsectionrsimilarr to Figurerl of a modified form ofiplant'; Figures 5 and 6 are:=details, and v Figure 7- illustrates a modifiedparrangementf suitable for use where. head rfoom 'is limited. i v Referring *to the construction: illustrated in Figures 1 i to :3, rthe ipl'a-ntcomprisest roasters 11 of the circular-whearthtypeerranged in grou'psiof six a-bovelreverberatory furnaces l2, as bestrseeniniFigure '8,a Eachrgmupiof six roasters is arranged iII tWO'SLi bigI'OWPS of three set in line with one another transverse- 7 1y tothe length ofrthe reverberatory furnace below; f "Below and 'between each pairiof the roaste-rs .111 each sub-group are calcineshoppens-18, '14,; one in each sub-group above each of the; sides of the reverberatory; furnace;

The outer roasters 11 are provided with chutes 15 to the calcine-hoppers and the centre roaster 11 is provided with two chutes 16 one leading to one of the hoppers 13 and the other leading to one of the hoppers 14. These chutes are provided with suitable control means, not shown in the drawings and thus the centre roaster in each sub-group can discharge to either of the discharge hoppers 13 or 14, as desired.

Considering now the connections from the calcine hoppers to the reverberatory furnace 12, these are best illustrated in Figures 1, 5 and 6, from which it will be seen that the two hoppers 13 are connected by chutes 20 to amain ore delivery pipe 21. The pipe 21 is branched to provide a considerable number of ore inlets 22 to the furnace and the junction of each branch with the main pipe is controlled by a deflector valve the casing of which is indicated at 23. The deflector valve contains a pivoted vane 230 whereby the branch may be opened or closed from an external rock-shaft. Thus calcine flowing from either of the calcine-hoppers 13, can be di rected into the furnace through any one of the branches 22. The calcine-hoppers 13 are of small size and are intended merely to take care of periodic variations and the discharge from the roasters. The ore feed to the furnace is substantially continuous, calcined ore being delivered through each of the branches 22 in rotation.

As will be seen from Figure 2, there are two sets of branches 22 and main ore delivery pipes 21, one supplied from the hoppers 13 and allocated to deliver ore to one side of the reverberatory furnace and the other being supplied from the hoppers 14 and allocated to deliver ore to the other side of the reverberatory furnace 12. At the point where the branches 22 enter the furnace they are provided with a bend or knee 24 (see Figure 6) to break the fall of the calcined ore and prevent it from entering at too great a velocity.

To obviate any chance of clogging at this point the bend 24 is provided with a pokehole 240 and a lift-up lid 241 through which a rammer may be inserted if any clogging occurs. The bend or knee 24 rests upon a water-cooled cast copper delivery chute 242 built into the angle at the junction of the roof and the wall of the furnace. Suitable links and levers may be provided, if desired, for grouping together into one place the controls of the various deflector valves 23.

Above the valves 23 and branches 22, but below the calcine hoppers 13, there is located a car-platform 25.

Rails 26 run along the platform below each of the sub-groups of the roasters and the two lines of rails are inter-connected by a crossover 27. A junction track 28 running off to a waste dump may also be provided. Upon the rails are cars 29 provided with calcine-hoppers 30. Auxiliary discharge chutes 31 from the calcine hoppers are placed to deliver, when required, into the hoppers on the cars and the hoppers themselves have discharge chutes 32 for delivering to auxiliary distributing pipes 33. The auxiliary distributing pipes deliver to the main ore delivery conduit 21 above the branches 22. Thus ore may be drawn from the roasters above any one of the reverberatory furnaces and charged into the car 29 for delivery to any other of the reverberatory funaces.

The furnace 12 is shown provided with a powdered fuel burner and a hot blast supply pipe 41.

The gas exits of the roasters 11 pass upwardly, as shown at 51, and enter a dustflue 42, which is common to all the roasters and which delivers by branches 43 to a Cottrell dust collector the finer dust, which is not shown in the drawings. The dust-flue 42 comprises dust-pockets 45 and the Cottrell or other dust collector also has dust-pockets which are indicated at 46. The dust-pockets are all connected by chutes 47, 48 to the calcine hoppers 13 and thus any dust which passes out of the roasters is collected and returned for treatment in the reverberatory furnaces.

The roasters are charged in the usual way from hoppers 48 located above them.

In the operation of this apparatus the roasters deliver continuously to the intermediate calcine hoppers 13, 14 and these deliver continuously or intermittently to the reverberatory furnaces through the main ore delivery pipe 21 and the branches 22. The branches 22 are opened one by one in rotation and only one branch. is normally kept running on each side of the furnace at one time. Thus the ore may be delivered continuously to the furnace in small batches at different points in rotation and the amount charged into the furnace at any one given point can be kept down so as not to reduce the temperature of the furnace except at that point. The molten matte and slag are periodically drawn off from the furn ace and this may be done with out interfering with the charging operations. When all the supply branches 22 have been utilized in turn operations are recommenced 1 at the first of the branches 22 and the cycle is repeated indefinitely.

If any one, or even any two, of the masters fall out of operation for any cause such as necessary repairs, either side of the furnace can still be kept evenly supplied by means of the other roasters in the group owing to the fact that the calcine hoppers 13 which belong to two sub-groups are connected together to supply one half of the furnace, and the calcine hoppers 14, which also belong to two subgroups, are connected together to supply the other half of the furnace. Thus the subgroups are interconnected and also, the centre roasters of each group, can supply either the hoppers 13 or 14, as desired, the dlscharge from the roasters of each subgroup may be mixed. Thus either one of themain ore delivery pipes 21 may be kept supplied even though any given two of the roast- 'car-and-track system provided.

Moreover, if any one of the reverberatory furnaces has to be shut down temporarily for repairs the roasters over it may continue to operate at reduced capacity and thefdilficulties of getting them started up again after the reverberatory furnace is repaired can be avoided by transferring the calcine from such roasters in the calcine cars to another reverberatory furnace.

The whole system is thus flexible and adaptable to meet all probable variations of operating conditions. Owing to the fact that the calcined ore is kept continuously in mo tion and is not long allowed to accumulate or remain at rest in the hoppers, caking is obviated, and as large charges of calcine are not fed into the reverberatory furnaces, large variations in furnace temperature are avoided.

Referring to the modification illustrated in Figure 4, it will be seen that, as before, there are roasters 11 connected to calcinehoppers 13. Other calcine hoppers 14 for the other side of the reverberatory furnace 1 12 would be provided as before and likewise furnace.

cars 29 with associated parts.

delivery pipe 21, however, instead of being' there is the intermediate car-platform 25 and The main ore provided with branches controlled by deflector valves delivers to a conveyor conduit 121 and the conveyor conduit 121 is provided: with the branches 22 for delivery of the ore The coveyor conduit 121 isto the furnace. of a deep rectangular section and extends in a horlzontal direction above the furnace, one

conduit being located above each side of the The branches 22 are controlled by valves 123. Within the conduit 121 is a scraper conveyor 124 by which the ore is carried to the branches 22.

Referring to Figure 7 it will be seen that this is in principle similar to the arrangement of Figures 1 and 2, roasters 11 being provided above calcine hoppers 13 which are connected by a pipe system through branches 22 to a reverberatory furnace 12. Instead, however, of a single main'ore-delivery pipe which receivesealcine from both hoppers 13, and distributes it over the whole length of the reverberatory furnace, the chutes from the hoppers 13 unite at 121, but from this point the distribution only takes place over a portion of the length. The ends of the area along whichdistribution takes place are supplied by separate branches 122, 123. In other respects the arrangement is similar to Figure 1. In this case the main ore delivery pipe :maybe regarded as Lthe :junc-tionipiece 1 2 1, thei'branches- 122, 123 being Fsubsi'diary.

It :1 is to be :understood that, while this. :inventionlhasibeenz describediwith reference to particular embodiments thereofzzin the z ac :eompanyingjdrawingsethisshasiloeendoneiby exeinplification only and, the accompanying claimsxare:intendedito beread in theirzbroad- :est significance.- 'iIt" is tosbe :noted thatfalthough a specific arrangementrof subsidiary wore from 'stlreroasters to .the reverberatoryfiklg furnace whichrcompriseftwomaintore deliv- "cry ipipes one: allocated 3130 each side of the furnace, eachsof: saidmain ore: delivery pipes being adaptedr to pass 'continuously' the main ore supply zfOIi the: whole side 1 of 2theiili furnace tO'iWl'llClLit is allocatedflneans to dis tri'bute': ore itO a-each side of-the furnace; from the respective main :ore: deliverywpipes .therefor and connections-from a group of the roasters to each main ore: delivery-pipe:whihfiEes comprise intermediate calcine hoppers 321110- cated oneYbetw'een' each adjacent pair of roastersszto receive r calcinertherefrom andfito deliverrsaid rcaleineto .=the main 5 oreidelivery 'pipesi 2. .An. ore-reducing .plant :as: claimediin claim 1 1 wherein ithe means for distributing 'orefromrthe main orerde-livery pipecomprises a pluralityi of lateral branchestherefrom to :various points inithe length of the furnaceri and'zsaid lateral branches enter the furnace 1 'by'means 0f abenhpa-ssage, (whereby the velooityy'ofrentryzofathe: material tOFllhQ afurnace is c'hecked. i

saidilateral ibranch-es enterxathe; furnace by means ofarbent ipassage, .wherehyrthez velocity of entry, of the material to the furnace is chec-kediand awater-cooled delivery chute is providedifroursaidibend into. the" furnace.

4. An ore reducing plant as claimed inmzo claim 1 wherein the roasters have gas-exits which deliver to a hoizontal dust flue common to a plurality of roasters, the dust flue delivers to an exit pipe, and dust-pockets are provided in said dust flue having delivery- 125 chutes to said calcine-hoppers.

r 5. In an ore reducing plant, the combination of a reverberatory furnace, a plurality of roaster furnaces located thereabove, hoppers below the roaster furnaces to receive the- .An ore reducing plant as claimed ina product thereof, two main ore delivery pipes, one allocated to each side of said furnace, connections from said hoppers to said dclivery pipes whereby the whole ore supply for the reverberatory furnace passes through the said two pipes, and distributing means from said main ore delivery pipes to said reverberatory furnace comprising a system of branch pipes therefrom and a valve for each of said branch pipes.

6. Ore-reducing plant as claimed in claim 5 wherein a plurality of reverberatory furnaces and roaster-s are employed, said hoppers being provided with auxiliary delivery means and transportable receivers, and said distributing means being provided with auxiliary admission conduits; whereby product from the roasters allocated to one furnace may be transferred when desired to the distributing means allocated to another furnace.

7. In an ore-reducing plant, the combination of a reverberatory furnace, roaster furnaces disposed thereabove, a plurality of calcine hoppers below said roaster furnaces to 2 receive the product thereof, and a system of inclined interconnected branching conduits beneath each of said hoppers provided with deflecting valves at said branches and adapted to direct the product from one of said.

hoppers at will to any point desired along the length of a side of said furnace.

S. In an ore-reducing plant, the combination of a reverberatory furnace, roaster furnaces thereabove in a group which comprises a plurality of roaster furnaces allocated to deliver ore to one side of said reverberatory furnace, and a plurality of roaster furnaces allocated to deliver ore to the other side of said reverberatory furnace, calcine hoppers below the roasters to receive calcined ore therefrom, likewise allocated each to one side of the reverberatory furnace, one or more intermediate roaster furnaces, means to deliver calcined ore therefrom alternatively to calcine hoppers allocated to either one or other side of the reverberatory furnace at will, a car-platform below the calcine hoppers but above the distributing conduits, cars on said platform, and means to divert calcined ore from the calcine hoppers of one furnace to the cars, and to deliver it from the cars to the distributing conduits of another furnace. In testimony whereof I affix my signature. ALEXANDER GRANT MGGREGOR.

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