US1100972A - Electrical furnace for the reduction of copper and other ores. - Google Patents

Description

W. H HAMPTON. ELECTRICAL FURNACE FOR THE REDUCTION OF COPPER AND OTHER ORES.

APPLICATION FILED OCT. 7, 1913.

Patented June 23, 19M,

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I/NM 7% W. H. HAMPTON, ELECTRICAL FURNACE FOR THE REDUCTION 0? GOP? R AND OTHER ORBS,

APPLICATION FILED 0017,1913.

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W. H. HAMPTON. I ELECTRICAL FURNACE FOR THE REDUCTION OF COPPER AND OTHER GEES.

F w: mm me APPLICATION FILED OCT. 7, 1913 Patented June 23, 1914,

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prises UNITED STATES PATENT OFFICE.

WILLIAM H. HAIJPTON, OF NEW FURNACE COMPANY, INCORPORATED, 0F

Tron or DELAWARE.

YORK, N. '55., ASSIGNOR TO THE GONLEY ELECTRIC WILMINGTON, DELAWARE, A. CORPORA- ELECTRICAL FURNACE FOR THE BE DUCTION 0F COPPER AND OTHER 03.115.

Specification 05 Letters ratent.

Patented June 23, 18 1 1.

Application filed October 7, 1913. Serial No. 793,817. i

To all whom it may concern.-

Be it known that I, W'ILLIAM H. HAMP- son, a citizen of the United States, residing at New York, in the county and State of New York, have invented certain new and useful Improvements in Electrical Furnaces for the Reduction of Copper and other Ores,

of which the following is a specification.

This invention relates to metallurgical furnaces for the smelting of ores, and more especiallyto furnaces for the reduction of copper ore and other ores requiring similar treatment.

The particular object in View has been to produce an electrical copper-reduction furnace which is elfective for the purpose for which, it 18 designed and advantageous by reason of the rapidity and economy of served.

In the accompanying drawings. which illustrate the invention somewhat schematically: Figure 1 is a vertical longitudinal section through the furnace; Flog. 2 is a vertical section taken at right angles to Fig. 1 and showing also a fore-hearth or settling and refining furnace to facilitate separation by gravity of the metallic products from the slag; Fig. 3 is a horizontal section through the refining furnace or fore-heart Fig. 4 is a horizontal section on the line P t of Fig. 1; and Fig. 5 is. a section on theline 55 of Fig. 1.

i The furnace is a shaft furnace, preferably of horizontally elongated form and comanupper shaft portion and a lower shaft portion. ln'lmediatcly above the lower shaft portion the side and end walls of the upper shaft ortion slope inward and downward as indicated at 10. so that the crosssectional area of this shaft portion diminishes in the direction of descent of the per shaft portion; and the portions of the masonry which separate the small shafts from each other are consequently tapered or brought to a J-ridge at the top, as shown at 13, thus efiectively parting the charge as it passes from the upper shaft portion to the lower shaft portion.

A hood 15 is shown covering the top of the upper shaft portion, and there is a door 16 in this hood through which-the charge may be admitted to the shaft. A duct 1' 7 leadingfrom one end of the hood and an exhaust fan 18 therein provide for the rying off. of the fume and gases resulting from the smelting operation. 7

Below and in direct communication with the separate small shafts 11 is a common hearth 19 having-a slag exit 20 and an exit 21 for the metallic copper or matte, as the case may be. The tapering part of the up per "shaft portion. thesmall shafts 11 and the common hearth are all provided with a suitable lining. indicated at 22, which may be of acid. basic or neutral character, preferred or found desirable. This lining need not be extended up into the vertical walled portion .23 of the shaft intervening; between the hood 15 and the portion having the sloping walls 10. i

' Both thetapering' part of the upper shaft portion and the separate small shafts ii are heated by radiation from electrical resistance elements 24 and 25 located in their side walls and kept from contactwith the charge by the lining 10. These elements are non-metallic and of comparatively Inassive character, being preferably composed of a mixture of graphite and clay in the proportions of forty per cent. (40%) carbon and sixty per cent. clay. Upon the passage of a suitable electric current they become incandescent. and the heat thus generated is radiated inward into the charge in the shaft. Consequently. the addition of fuel to the charge for supplvinr heat and the use of an air blast are avoided, and it is, therefore, possible to govern the action in the furnace exactly and to operate on finely ground ore. with the consequent advantage of speed of reduction and fusion andwithoutthe danger of loss by volatilizations and by blowing: away the fine material with the air blast, thus avoiding the making; of fine dust.

The resistance elements 24 of the upper shaft' portion are preferably in the form of bars disposed longitudinally, that is to say, running up and down, and each is provided at its opposite ends with terminals 26, preferablyof pure carbon. These latter are connected with the resistance elements by intermediate members 27, which are desirably composed of a mixture of clay and graphite of conductivity greater than the elements 24 but less than the terminals 26.

-The terminals 26 are shown secured in sockets in these intermediate members, and the latter are in turn cemented to the outer faces of the resistance bars. The heating elements 24 of the small shafts l1 are'preferably in the form of rings which encircle these shafts. These resistance elements are provided at opposite sides with other pure carbon terminals 26, which are connected with the rings by intermediate members 27 in substantially the same manner as inthe case of the elements 24. As indicated in Fig. 4, the resistance elements may be connected in parallel in a circuit 28, and it is obvious that the elements 2 1- may similarly be connected in parallel in a circuit indicated at 29 in Fig. 2. These two circuits are independent of each other and enable the temperatures of the two shaft portions to be relatively varied in order to secure any particular temperatureconditions desired. Preferably these circuits form the secondaries of transformers 30, fit. of which the primary circuits are indicated at 32 and 33. Variable resistances 34, 35 in the secondaries enable the currents supplied to the resistance elements to be varied.

Cooling means are provided, more especially for avoiding overheating of the terminals located in the walls of the furnace. To this end suitable water pipe lines or ducts 36 are led through the masonry above and below each terminal and at other points Where desired, and are connected at their endswith suitable stand pipes '37. These cooling passages are located near the outer surfaces of the wall, so as not to diminish the heating effect of the resistance elements upon the charge in the shaft. Means are also preferably provided for supplying air to the upper or tapering shaft portion when desired. To this end this portion of the shaft is provided with ports 38, opening through the inner surfaces of its sloping Walls and forming the delivery ends of ducts 39, which extend inward through the masonry and are connected by suitable branch ducts 40 with air pipes 41 that extend along through the walls, one end of each of the pipes 41 being connected with a pipe 42 leading from a suitable source of supply, such as a fan blower. The construction shown is, of course, susceptible ofvariation, but it is desirable since it enables the ducts 39 to be extended all the Way through the walls, thus affording facilities for cleaning. The outer ends of these ducts are normall closed in any suitable manner. It will be observed that the air which may be admitted through the ports 38 enters at an entirely different and much higher level than is the case in blast furnaces where air is supplied to the lower part of the shaft for the purpose of burning the fuel in the charge and thus generating the heat necessary to produce and maintain the reduction and fusion of the ore. In fact, the air admitted in my furnace is for an entirely different purpose, namely, to effect a roastin action in the upper shaft portion when suc action may be desirable. The pressure and quantity of air thus admitted may be varied ac-- cording to conditions, but would naturally not be anywhere near as great as in the case of the air supplied in an ordinary blast smelting operation. Air may be delivered through these ports at any time when it is desired to eliminate sulfur or other impurities which may exist in the charge as introduced into the furnace.

In the operation of the fore-hearth the slag opening 20 is closed and all the fused mass of slag and metal or matte is discharged through the opening 21 into the refining furnace 44. When the temperature is raised, thinning the slag, separation takes place by gravity and the metals are drawn off from time to time through 45. The slag may run continuously off through discharge opening 46.

The discharge opening 21 at the bottom of the hearth 19 constitutes the entrance to an inclined passage 43 which delivers into the lower part of a fore-hearth or refining furnace 44. This fore-hearth constitutes an inclosed chamber, which is preferably circular and vertically disposed. It is provided with a lining 22, like that of the main furnace, and a similar lining is also placed in the passage 43. The fore-hearth has a discharge opening 45 at the bottom for me tallic copper or matte, as the case might be, and an opening 46 near the top through which the slag is removed or allowed to escape. The walls of the fore-hearth are heated by annular resistance elements 47, similar to the elements 24 and 25 and like them rovided with terminals 26" and interme iate members 27". They are suitably connected in a circuit or circuits 48 forming the secondary of a transformer 49. There ma be any suitable number of the elements 47, ut, as shown, there is one resistance ring below the discharge end of the passage 43 and two rings above the same and below the slag exit 46.

In operation the ore in finely ground condition and mixed with approximately the exact amount of carbonaceous fuel necessary for the reduction, together with appropriate fluxes, such as limesto'iie or silicious ore, is charged into the shaft of the furnace. In its descent it is heated first by the resistance elements 24 and then by the elements 25. Under the influence of the high temperature thus produced in the tapering shaft portion 10, the oxygen which may be contained in the ore iscaused to combine with the carbon for reduction, and the resulting gases arise through the charge and are led off through the ducts 17. In con sequence of this reaction the charge diminishes materially in bulk, and this shrinkage is compensated for by the decreasing cross-sectional area of the shaft as the charge descends. At the bottom of this shaft portion the charge, which is now in a more or less reduced and fused condition, is divided and enters the several shafts ll, of which there may be any desired number. Here the material encounters a temperature which may differ from that in the upper shaft portion according as conditions require, and the reduction and fusion are completed. T he'action is greatly facilitated by I the fact that the charge is divided into sevetfect'a heated settling chamber.

eral comparatively small bodies, which are encircled by the heating elements All the particles in these portions of the shaft are therefore heated to a high temperature almost instantaneously, and by reason of this fact and the finely divided condition of the-material fusion is effected very rapidly. The combined cross-section of the several shaft portions 11 is less than the area of the upper shaft portion. Preferably, also, the hopper-like entrances 12 at. the upper ends of the small shafts 11 have a less abrupt slope than the walls 10. These factors are of importance to the success of the operation. 7 w

The molten material which descends from the small shafts 11 into the common hearth may be metallic lead, copper, etc., or mattes, according to the nature of the charge and the manner in which the smelting operation has been conducted. The slag, which floats on top of the metal, is allowed to escape more or less continuously from the slag exit 20 if no fore-hearth is used. Th-en the fore-hearth is employed slag may or may not be removed from the hearth of the main furnace; in any event the material is con.- dueted to the fore-hearth 14-, which is in Here the I slag rises to the top and is allowed to escape continuously from the slag opening 4-6, while the metallic lead, copper, etc. or matte is drawn off from time to time through the opening 45. The heating of the walls of the fore-hearth by the resistance elements 47 is of great advantage in that it prevents material adhering to these Walls. It raises the temperature of the slag as much as desired to make it thinner or more liquid to permit the small globules of metal or matte to settle down and out. This has formerly been the source of a large amount of trouble and loss, which is obviated by my construction.

\Vhat I claim as new is:

1. A copper reduction furnace comprising a plurality of shafts having electrical resistance heaters in their walls, an upper shaft portion common to said shafts, and electrical resistance heaters in the walls of said common shaft portion.

2. A copper reduction furnace comprising a horizontally elongated upper shaft, a series of smaller shafts atthe bottom thereof, and resistance heating elements at the sides of said smaller shafts.

3. A copper reduction furnace comprising an upper shaft portion, a hearth, and intermediate said shaft portion and hearth a plurality of small shafts of materially smaller (-(nnbined area than the upper shaft portion, said upper portion cdnstituting a single shaft common to said plurality of shafts, and resistance heating elements at the side of said small shafts. f

4. A copper reduction furnace comprising a horizontally elongated upper shaft portion, a series of small circular shafts at the bottom thereof, and electrical resistance heaters disposed at the sides of said shafts. A copper reduction furnace comprising an upper relatively large shaft portion, a plurality of small shafts having hopper-like entrances at the bottom of said large shaft, and electrical resistance heaters at the sides of the shafts.

(3. A copper reduction furnace comprising an upper relatively large horizontally elongated shaft section having inwardly slop ing sides and electrical resistance elements arranged to heat the same, a plurality of shaft sections of relatively small combined area at. the bottom of the upper shaft section and having electrical resistance heaters in their walls, and a common hearth or chamber below said plurality of shaft sections.

7. A copper reduction furnace comprising an upper relatively large section having electrical resistance heaters in its walls and means for introducing fluid into its interior, and a plurality of relatively small shaft sections at the bottom of the upper shaft section and also having electrical resistance heaters in their walls.

8. A copper reduction furnace comprising an upper common shaft section having resistance heaters in its walls, a plurality of relatively small shafts at'the bottom of said upper shaft and also having resistance heaters in their Walls, and means for relatively resistance elements outside of said reduction furnace and connected with said space.

In testimony whereof, I have signed my name to this specification, in the presence of two subscribing witnesses.

WILLIAM H. HAMPTON.

l/Vitnesses LOUELLA F. Ln'rLE, J. J. KozmN.

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