US1800721A - Electric smelting furnace - Google Patents

Description

A r l '14, 1931. a DYER ETAL 1,800,721

ELECTRIC S MELTING FURNACE Filed Nov. 2, 1928 5 Sheets-Sheet 1 Ig l i/* J BY Rolandl. suuwrzmd' ATTO EY.

April 14, 1931- E. DYER ET AL ELECTRIC SMELTING FURNACE Filed Nov. 2, 1928 5 Sheets-Sheet 2 I N V EN TOR Z76 er! .0 flolamllf 2 zzi/zcrland A ATTORNEYS.

E. DYER ETAL 1,800,721

ELECTRIC SMELTING FURNACE Filed Nov. 2. 1928 5 Sheets-Sheet 5 INVEN TOR.

Elbert fl r By RolandE'Suf/ierlaml April 14, 1931.

5 Sheets-Sheet 5 Ell III/J! /V///////I// f/A z INVENTOR. Elbert .0 er

Roland E. uiherlaml ATTORNEYS.

P 1 9 E. DYER ET AL ELECTRIC SMELTING FURNACE Filed NOV. 2, 1928 Patented Apr. 14, 1931 UNITED STATES PATENT OFFICE ELBERT DYER AND ROLAND E. SUTHERLAND, OF BAlNDON, OREGON, ASSIGNORS TO MINERAL POWER 00., OF PORTLAND, OREGON, A CORPORATION OF OREGON ELECTRIC SMELTING FURNACE Application filed November 2, 1828. Serial No. 316,801.

This invention relates to a method of smelting in an electric furnace, filed concurrently herewith and relates thereto.

The primary purpose and object of our invention is for the continuous smelting of ores wherein a minimum of electrical energy will be required in effecting the smelting.

The invention, consists primarily of a relatively air-tight shell member made relatively narrow in the direction of flow of the materials to be smelted and having a plurality of electrodes disposed within the shell area to facilitate the discharging of the electrio current across a gap and to require the passage of the materials to be smelted through the arcing zone; means being provided within the shell and through the shell Wall for the tapping off of the liquid residue at different elevations in order that materials-of different specific gravities may be withdrawn at different elevations; means being provided for maintaining the liquefied mass in a highly fluid condition; means being further provided for the tapping off of the slag residue at a higher elevation within the furnace and for maintaining the slag also in a highly fluid condition.

Itis desirable also in devices of this kind to facilitate the withdrawal of the volatile content from the furnace. 7 To facilitate the withdrawal of the volatile content and to lessen the oxidization of the same we create a partial vacuum, or negative atmospheric pressure within the retort itself.

We have found through repeated experimentation that where the smelting is carried on substantially in the absence of free air, or where a limited amount of air is admitted into the smelting area that the electric current consumption is greatly lessened, that the electrodes last for substantially longer periods of time, and that the metallic contents of the gases may be recovered in substantially larger quantities and in larger percentages, and that the separation into the different constituent groups, is greatly facilitated.

A further object of our invention resides in a relatively narrow furnace structure and wherein a plurality of electrodes are disposed in spaced relationship with each other, longitudinally of the central furnace area so that the mass being treated while in a solid state, and in the sponge state, and in the liquid fluid state, may be required to pass through the arcing gap of the various electrodes to hasten the smelting process and the refining of the mass being treated and the volatilization of those component elements constituting a substantial part of the mass being treated.

A further object of our invention resides in providing independent means for supplying electric current to each electrode unit and automatic means for the maintaining of the electrodes in proper feeding condition.

A further object of our invention resides in a feeding chute and feeding head wherein the materials are deposited within the chute periodically and wherein an air seal is provided at the entrance of the chute eX- cepting as the periodic feedingoccurs. A substantial head of fed material being maintained so that the mass to be smelted is fed to the arcing and melting area as a continuous feeding condition.

We have found, through repeated tests, that a lesser amount of electric energy is required where the smelting occurs within the arcing gap, and that a very much larger metallic recovery content obtains than where the smelting process is carried on by radiation and wherein the materials being smelted are smelted as charges rather than as a continuous smelting process, and We have therefore provided means for the continuous reduction of the mass within the continuous or periodic withdrawal of the component residues at different elevations through the wall structure of the furnace itself.

We have found through experimentation that the smelting process may be increased in efficiency depending upon the character and kind of ores beingtreated wherein the furnace itself may be tilted about a horizontal axis to facilitate the run out of the fluid residues.

A further object of our invention resides essential elements of which are set forth in P the appended claims, and a preferred form .of embodiment of which is hereinafter shown with reference to the drawings which accompany and form. a part of this specification.

In the drawings: I

Fig. 1 is a side elevation, partially in section of the assembled device.

Fig. 2 is a fragmentary, vertical,-sectional elevation of the assembled device in preferred embodiment. I

Fig. '3 is a vertical, sectional, end view of the retort or furnace, the same being taken on line 3-3 of Fig. 1, looking in the direction indicated.

' Fig. 4 is a perspective, end view of the bottom of hearth electrode.

Fig. 5 is a sectional, side elevation of the vacuum creating head, disposed within the discharge outlet from the volatile areas of the furnace.

Fig. 6 is aside elevation of a modified form of construction wherein the mass to be smelted is deposited through a cylindrical hollow electrode .and flows through the electrode and into the arcing gap within the smeltin area.

Fig. is a fragmentary, sectional, side elevation of the mechanism illustrated in Fig. 6, the same made to illustrate the feedin of the mass through the hollow electrode.

Tig. 8 isa vertical, sectional elevation of a modified form of construction wherein the hearth of the bottom electrode is made of a circular disk adapted to being rotated about a substantially vertical axis and where the mass to be-smelted is deposited upon the rotating electrode disk.

Fig. 9 is a horizontal, sectional view, taken on line 99 of Fig. 8, looking in the direction indicated.

Fig. 10 is a vertical, sectional, side view of a modified form of furnace structure where the mass to be smelted is deposited upon a shrouded rotatable wheel-like electrode disposed within the furnace.

Like referencev characters refer to like parts throughout the several views.

We preferably form the body portion of our furnace of a plurality of stacked sections, the bottom section 1, being mounted upon suitable supporting stands 2 and 3. The base of the stands resting upon a proper permanent foundation. Trunnion bearings stands 2 and 3.

It is highly desirable in order to obtain the greatest efficiency from this form of an electric smelting furnaceto tilt the body' portion of the furnace to facilitate the outer flowing of the resultant liquid mass developed within the furnace area. To accomlish this result we place a tiltin jack at the rear end of the body portion; the jack may be made in any form suitable to the requirements of the work and may consist of a cylindrical body member 6, supported upon a suitable journal pin 7. The journal pin 7 being disposed within bracket bearings 8,

resting upon thebase 9. A threaded stem 10 depends from suitable brackets 11 secured to the body of the retort frame. The stem 10 being journaled about a journal bearing 12. The threaded head 13 is in threaded relationship with the stem and rests upon the cylindrical body member 6. The rotating of the head 13, imparts a longitudinal movement to the stem 10 and tilts the furnace to the desired angle. The body portion of the furnace is preferably made of a plurality of units consisting of the base 1, and the central portion 14, with asuperposed housing15, in which is disposed automatic devices for the feeding of the electrodes as erosion occurs upon the lower end thereof. A suitable refractory lining 16 is disposed within each of the body portions of the furnace with a hearth electrode 17 disposed central of the feeding end of the furnace. Materials to be smelted are deposited within the feeding hopper 18, from a source of ore supply not here shown. A'feeding head 19 is disposed within the base of the feeding 'hopper, the'same consisting of a disk having a cut out portion 20 to form a pocket into which the ore to be smelted gravitates and a specified amount of the same is fed into the ore chute 21 at each rotation of the feeding head 20. The amount of ore to be fed per unit of time may be regulated by the rate of rotation of the feeding head or by the size of the pocket disposed within the head. Power means being provided for rotating the shaft 22 upon which the feeding head 19 is disposed. The chute 21 is preferably made in increasing cross sectional area downward to facilitate the downward fiow of the mass to be smelted; the toe of the mass being deposited upon the hearth 17 immediately adjacent the lower end of the electrode 23. A plurality of electrodes are disposed in spaced relationship with each other and in substantial parallel alignment with each other. Each electrode being adapted for independent feeding and to being supplied independently with electric energy. The stem 24 of the electrode passing through the crown wall of the furnace is removably secured to the connecting crown of the electrode 23. Electric energy being supplied to the electrode from a source of supply not here shown through the conduit 26 and the conduit 27 An automatic feeding of the electrode being accomplished through the automatic feeding head 28. A primary crown 29 is disposed in spaced relationship with the hearth 17, so that the ore to be smelted passes through a limited heat zone 30 and the melting down of the ore occurs by direct contact with the are by passing through the gap disposed between the electrode and the hearth; each of the electrodes'pass through.

an insulating nonfusible core 31 disposed in the crown 29 with a relative close fit being maintained therebetween so that a much higher temperature prevails in the area 30 of the retort chamber than occurs in the zone area 31 of the retort chamber. A refractory lining 32 being disposed beneath the crown sheet 33 and an insulating lining 34 as diatomaceous earth is disposed upon the upper part of the crown sheet 33. The insulating lining34 being of suflicient thickness to reduce the temperatures disposed within the housing 15 to a proper working temperature. The passing of the ore, and the liquefied mass emanating therefrom, through a plurality of arcs refines the metallic content disposed within the mass. It also volatilizes practically the full volatile content of the mass, so that the liquid passing into the reservoir 35 is devoid of ractically the entire volatile content 0 the same; the heavier materials gravitating to the bottom of the reservoir, the resultant groups of different specific gravities, may be tapped off through tuyeres 36, 37 and 38, disposed at difit'erent elevations through the wall of the furnace. The fluid mass disposed within the reservoir 35 being maintained in a highly liquid conditionthrough the electrode 39 disposed within the spaced walls 40 of the cylindrical housing 41. The lower end of the cylindrical housing 41 extends downward into the reservoir area and the gap 42 is'maintained between the lower end of the electrode and the upper surface of the metallic content of the reservoir thereby maintaining a relatively high temperature therein. his also maintains the slag in a liquid condition, the slag being tapped off through a goose neck tuyere 44, outwardly extending through the side wall of the furnace. The heat of liquefaction ofthe slag being supplied through electrode 45. The Volatile fluids emanating from the mass being treated are tapped off through the discharge outlet 46 and a negative atmospheric pressure is maintained within the retort area by the placing of a relatively high pressure water jet within the discharge head 47 disposed in registerable alignment with the discharge outlet 46. The water for maintaining thevacuum creating, jet head, being supplied through the water pipe 48. The gaseous fluids being withdrawn from the furnace area are directed through the outlet 49 into the condenser coil 50. The condenser coil being disposed within the condensing chamber 51, of the condenser case 52. The coil 50 should be of suflicient length to completely condense the fluids passing theretlirough. The gas being deposited through the outward end 53 of the condenser coil and the metallic content being deposited within the liquid holding reservoir 55. The water and other fluids of relatively low specific gravity flow outwardly from the liquid holding reservoir 54 through the discharge spout 55 and the metallic content precipitated in the base of the liquid holding reser voir 54 may be withdrawn through any suitable opening 56 disposed within the base of the liquid holding reservoir 54. Such gases as do not condense are discharged through the discharge outlet 57 of the return tube upwardly extending from the condensing coil 50.

A diaphragm 58 is disposed within the liquid holding reservoir and downwardly extends from the crown sheet 59 so that the liquids entering the reservoir 54 are required to pass downward and pass the lower edge of the diaphragm 58 in order to be discharged from the discharge spout 55. A change in direction of flow of the volatile contents is made as illustrated in Fig. 1, wherein the discharge outlet 57 is upwardly inclined and'at an angle to the liquid discharge 53 disposed at the terminal end of the condenser coil 50. Where it is desired to force all material through the liquid holding reservoir 54, a valve 60 may be placed in .the outlet 57.

It may be found desirable in certain classes of ore to build the retort as illustrated in Fig. 6 andin Fig. 7, wherein the ores to be smelted are fed from the hopper 61 into a hollow electrode 62 and the ores being fed are deposited from the electrode upon the hearth 63 and are then required to pass through the arcing zone of the electrode 62 and past the adjacent electrodes 64 and 65,'and to the arcing zone disposed at the lower end thereof. Suitable supporting and feeding means being associated with the hollow electrode for automatically feeding the same downward as the electrode erodes away at its lower end due to the arcing from the bottom of the electrode. The smelting being carried on in the absence of free air.

A furnace may also be made as illustrated 1n Fig. 8 and Fig. 9, wherein a rotating carbon disk 66-is disposed upon a suitable journal support 67 with suitable power driven means for rotating the journal support 67.

i The carbon disk is preferably inclined at an disposed within the furnace with stepped tuyeres 73 leading therefrom through the furnace wall. The volatile elements being withdrawn from the furnace through a discharge outlet 74.' The furnace, as illustrated in Fig. 8 and Fig. 9, is preferably carried 'upon suitable supports to facilitate the tilting of the furnace; and the furnaceis com-' posed also of a plurality of stepped refactory lined furnace elements. In the treatment of certain ores that may be reduced at relatively" low heat and where it is not desired to further refine the residue in thesmelting operation, the furnace may be made, as illustrated in Fig. 10, wherein a revolving carbon wheel 7 5 is journaled about a supporting water cooled shaft 76. The carbon wheel 75 is rotated in spaced relationship with the electrode 77 and the mass to be smelted is carried into the chute 78 by the feeding hopper 79 and deposits the material into the chute 80 and is carried by the rotation of the carbon wheel 75 through the arcing zone where the reduction occurs, and leads therefrom as a liquid into the liquid holding reservoir 81. Materials being reduced, are tapped from the liquid holding reservoir at different elevations through suitable tuyeres 82, leading through the walls of the furnace. The volatile contents are withdrawn from the furnace through the discharge outlet 83.

lVhile the form of mechanism herein shown and described is admirably adapted to fulfill the objects primarily stated, it is to be understood that it is not intended to confine the invention to the one form of embodiment herein shown and described, as

it is susceptible of embodiment in various forms, all coming within the scope of the claims which follow.

What we claim is:

1. In a device of the class described, the combination of a furnace shell composed of removable sections, each section being lined with a refractory lining, supporting and tilting means for said shell, a plurality of electrodes disposed in parallel spaced relationshi within the shell, each electrode having in ependent Wiring and feeding devices, means for tapping off the resultant liquid residue at dilferent elevations through the walls of the furnace and means for inof electrically heated electrodes disposed in spaced relationship with each other and in substantial alignment, independent means for automatically feeding each of the electrodes, a primary crown and a hearth disposed in spaced relation within the furnace, the electrodes passing through the primary crown and insulated therefrom, a liquid holding reservoir disposed withinthe furnace, tuyeres at different elevations leading from the reservoir, a discharge outlet for the volatile elements developed within the furnace, condensing means disposed within the discharge outlet and means disposed therein for creating a pressure below the normal atmospheric pressure.-

3. In a device of the class described, the combination of a plurality of refractory lined furnace units demountably assembled,

means for supporting and tilting the assembled furnace, means for electrically heating the furnace at a plurality of points spaced apart and in substantial alignment, means for feeding materials to be smelted into the smelting zone of the furnace, areservoir disposed within the furnace into which the molten mass gravitates, tuyeres at different elevations leading from the reservoir. through the walls of the furnace reservoir,

-an outlet leading from the interior of the furnace for withdrawing the volatiles, means disposed within the outlet for maintaining a pressure below the normal atmospheric pressure, and means for condensing the volatiles passing therethrough.

4. In a device of the class described, the combination of a furnace made of a plurality of stacked refractory lined furnace sections, to form a relatively narrow furnace having spaced side walls, a plurality of electrodes disposed in spaced relation with the side walls of the furnace and with each other, means for the independent electrifying and feeding of each of the electrodes, means for supporting and tilting the furnace to cause the molten mass to pass through one or more of the arcing zones of the electrodes, a liquid holding well disposed within the furnace, means for tapping the liquid holding well at different elevations and a discharge outlet outwardly extending from the furnace at a higher elevat1on than the top of the liquid holding well and means disposed therein for maintaining a pressure below .the normal atmospheric pressure within the furnace.

5. In a device of the class described, the combination of a relatively narrow furnace composed of side and end walls, means for the continuous feeding of materials to be smelted into the furnace, a plurality of electrodes disposed in spaced relation with each other disposed in the line of travel of the material to be smelted and after smelt-v electrodes disposed in spaced relation within the line of travel, independent means for feeding and electrif ing the electrodes, means for withdrawing the products of smelting from the furnace at different elevations and means for maintaining a partial vacuum within the furnace. 1

7. In a device of the class described, the combination of a relatively narrow and air tight furnace, a hearth and a vault disposed in relatively close spaced relation within the furnace and forming a channel through which the material to ,be smelted must continually pass, electrodes disposed in spaced relationship within the furnace and adapted to have their arcing ends disposed within the channel of the furnace, means for energizing the electrodes, means for independently and automatically feeding the electrodes into the channel of the furnace, and means disposed upon the furnace for maintaining a partial vacuum within the furnace.

8. In a device of the class described, the combination of a relatively air tight furnacev shell, refractory lining disposed within the shell, means for the continuous feeding of ore to be smelted intothe melting area, means for heating the resultant liquid mass, means for tapping off the liquid metal at different levels, means for tappin off and condensing gases from thedome o the furmice and means for maintaining a negative atmosphere pressure within the melting area of the furnace.

9. In a device of the class described, the combination of an air tight shell, refractory lining disposed within the shell, means for the feeding of materials to be'smelted into the heat zone of the furnace, means for.

automatically maintaining an electric arc in the path of travel of the materials to be melted, means for tapping the furnace at a plurality of elevations, and means for maintaining a negative atmospheric pressure.

within the melting zone.

10. In a device of the class described, the combination of a relatively air tight shell, means for feeding the material to be smelted into the heat zone, means for automatically maintaining an electric arc in the path of travel of the material to be smelted, means for keeping the elements disposed within the settling basin of the furnace in a highly fluid condition, and means for tapping the furnace at a number of elevations.

11. In a device of the class described, the combination of a relatively air tight shell, means for feeding the material to be smelted into the heat zone, means for automatically maintaining a plurality of electric arcs in the path of travel of the material to be smelted. means for keeping the elements disposed within the basin of the furnace in a highly fluid condition, means disposed upon the furnace for maintaining therein a partial vacuum, means for tapping the furnace at a number of elevations, and means for tilting the shell.

12. In a device of the class described, the combinati'on of a relatively air tight refractory shell, power driven means for feeding the material to be smelted into the heat zone, means for automatically maintaining a plurality of electric arcs in the path of travel of the material to be smelted, automatically controlled means forkeeping the elements disposed within the basin of the furnace in a highly fluid condition, a volatile discharge outlet leading from the basin, condensing means disposed within the discharge outlet including means for creating within the furnace a pressure below normal atmospheric pressure, and means for tapping the furnace at a plurality of elevations.

13. In a device of the class described, the combination of a relatively air tight shell, said shell comprising a plurality of chambers, a plurality of electrodes passing through two of said chambers, means for feeding the material to be smelted into the reducing zone, means for concentrating the intensive heat within the reducing zone, means for automatically maintaining a plurality of electric arcs in the path of travel of the material being smelted.

14. In a device of the class described, the combination ofa relatively air tight furnace shell, refractory lining disposed within the shell, a rotating disk rotatably disposed within the furnace shell, a cylindri cal electrode disposed vertical to the disk and within the shell, means for the continuous feeding of ore to be smelted into the melting area, means for tapping off the resultant liquid mass at different levels, means for tapping off the resultant gases from the dome of the furnace, and means for maintaining a partial vacuum within the furnace.

15. In a device of the class described, the combination of an air tight shell, refractory 6 1,eoo,721

lining'disposed within the shell, an inclined disk rotatably disposed within the furnace to form a melting hearth an electrode vertically disposed within the furnace and in spaced relationship from the disk, means for automatically.-maintainin the electrode in spaced relationship with the disk, means for the continuous feeding of ore to be smelted into the melting area, means for tapping the furnace at a"--plurality 'of elevations and means for maintaining 'a partial vacuum within the furnace.

16. In a device "of the class described, the combination of an air tight shell, refractory lining disposed within the shell, an inclined disk rotatably disposed within thefurnace, power means disposed outside the furnace for rotating the disk, an automatically controlled electrode vertically disposed within the furnace and in spaced relationship with the disk adapted to create an arcing contact with the disk, means for the continuous feeding of ore to be smelted into the melting area, means for tapping the furnace at a plurality of elevations, means for removin the resultant gases from the furnace an means for maintaining a partial vacuum within thefurnace.

17. In a device of the class described, the combination of a relativel air tight furnace shell, refractory lining disposed wlthin the shell, a water jacketed shaft horizontally disposed through the furnace, a disk secured to the shaft and within the furnace, an electrode disposed within the furnace, in spaced relationship with the outer periphery of the disk, automatic means for maintaining the electrode in arcing contact with the rotatable disk, means for the continuous feeding of 40 materials to be smelted into the heat zone of the furnace, means for ta ping oif'the resultant liquid mass at di erent levels,

means for removing the gas from the furnace, and means for maintaining a partial vacuum within the furnace.

- ELBERTDYER.

ROLAND E. SUTHERLAND.

Images