US1110359A - Electric zinc-furnace with integral condenser. - Google Patents

Description

G. V. THIERRY.

ELECTRIC zmc FURNACE WITH INTEGRAL CONDENSER.

APPLICATION FILED MAY 21, 1913. 1,1 10,359. ted Sept. 15, 1914.

WITNESSES. l/Vl/E/VTOR 7 M. A ATTOZHIVEKS.

CHARLES VICTOR THIEBRY, OF PAR-IE, FRANCE.

ELECTRIC ZINC-FURNACE WITH INTEGRAL CONDENSER Specification of Letters Patent.

Application Med May 21,

Patented Sept. 15, 1914.

191:. Serial no. man.

To all whom it may concern Be it known that I, CHARLES VIc'roR TIIIERRY, a citizen of the Republic of France, and a resident of the city of Paris, in said Republic of France, have invented certain new and useful Improvements in Electric Zinc-Furnaces with Integral Condensers, (Case A,) of which the following is a specification.

This invention relates to the metallurgy of zinc and the object thereof is to produce metallic zinc fumes by the reduction of oxid of zinc (ZnO) by carbon (C) and to subsequently condense said zinc fume to liquid metal.

The heat necessary for decomposing the ZnO and C is preferably derived from an electric current passed through a resistor, and the invention especially resides in particular means designed to a c mpli h the objects above stated.

The resistor is comprised in a bed of carbon, usuall made of coke, which is disposed upon a soe or hearth and is Confined by side walls. The size and shape of the carbon pieces as well as the depth, width and length of the resistor bed may be variously modified to obtain any desired electrical resistance and intensity of current, which is brought to the two ends of the resistor by blocks of amorphous carbon or graphite situated in the end Walls of the reaction chamber, that is, the resistor is interpolated between the two terminals. The reaction chamber of the furnace is made of sufiicient depth to receive the resistor and the charge; the latter being placed directly upon and sustained by the said resistor.

The charge in its entiret is either a mixture or alternate layers 0 igneous or commercial oxid of zinc and of carbon in preferably substantially such relative proportions as will effect, when suitably heated, practically the complete reduction and evolution of the charge in the forms of zinc fume (Zn) and monoxid of carbon (CO), that is to say, the amount of inert residual matter unevolvable in the gaseous form will usually be negligible for a considerable period of time.

As has already been intimated, the electric energy is transformed into caloric ener iathe resistor bed of the furnace and the oatfthus generated it the temperature is adequate, efl'ects the decomposition of the l superimposed mass, the following re resentative chemical reaction ensuing: Zn +C= Zn-l-CO.

The walls of the furnace immediately adjacent to the longitudinal sides of the resister and its superimposed charge and also the sole or hearth of the reaction chamber are utilized to condense the zinc fume and to evacuate the liquid metal and the residual gases to atmosphere. In other words, the longitudinal walls and the bottom of the reaction chamber, either or'both, are utilized as the condenser.

The reaction and its result represented by the classical formula, ZnO+C:Znl-CO, is not ordinarily precisely realizable in .practice; which is due to impurities in the reacting materials. However, as the present applicant has set forth in his patent No. 1,030,350, of June 25, 1912, it is nevertheless quite feasible not to collect sufiicient inert residual matter to materially interfore with runs of satisfactory duration.

The accompanying drawing illustrates one form of apparatus in which the invention is realized.

In said drawing: Figure 1 is a longitudi' nal center section, as on the lines A and B, of Figs. 2 and 3; Fig. 2 is a to plan view, developed from the plane S of 1%. 1; Fig; 3 is an elevation, as from the rig t or is hand ends of Fig. 1, and Fig. 4 1s a transverse center section, as on t e lines C and C of Figs. 1 and 2.

1 denotes the power circuit; D, D, the carbon terminals; H the bed-of-carbon resistor; J the charge; M the resistor-sole or hearth; N, N, the reaction chamber side galls; R a cover and T the reaction cham- The drawings purposely indicate what is regarded as a simp est possible construction which realizes the invention. ,In buildiug the furnace and condenser illustrated the hearth and the reaction chamber side walls are constructed of spaced suitable refractory bricks, blocks, slabs or tiles, as 5, which are set without mortar or cement (as in the usual manner) and the adjacent noncontacting surfaces provide therebetween fissures, slits, slots or crevices. These crevices may be vertical, as 6, or horizontal, or approximately horizontal, as 7, and both of these vertical and horizontal fissures may be combined in the same wall, or in the hearth, or in both. But in every case the said fissures or slits are characterized by the fact that their ends open respectively to the reaction chamber and to atmosphere.

The brick-work of the furnace should be bound together, as by the outer bracing, 8, Fig. 3, andby the embedded tierods, as 9, Fig. 4. In order to take the thrust of the bracing and also to maintain the initial spacing of the refractories, thin strips, orbuttons, as i, are variously inserted between the adjacent members, or such strips or buttons may be substituted by dabs of cement.

It is to be borne in mind that igneously produced or commercial oxid of zinc and coke or coal (carbon), as employed in a commercial operation, contains a sensible amount of moisture, entrained or in chemical combination; hence when a charge of these materials is inserted in the furnace the first effect will be to produce and drive off this moisture in the form of vapor. It is also a. fact that CG forms at a temperature considerably lower than and up to and even beyond that at which the reaction begins and when CO is evolved. The consequence of the foregoing conditions is that a certain volume of hydrous vapor and gas will be primarily produced in the reaction chamber and will find escape through the numerou fissures that are located at the sides of the charge and also at the sides and the bottom of the previous resistor. As this vapor and gas will be under some pressure it will prevent the entry of air and will also assist 1n progressively heating the sidewalls of the fissures. In the meantime the inner faces of the refractories, adjacent to the reaction chamber, will become heated to a temperature ap roximating that of the resistor and the c arge, while the said refractories will be heated by conduction in a rogressively diminishing ratio toward t eir outer surfaces. The foregoin conditions are favorable to the condensation of zincfume to liquid metal.

on the reaction is in progress the volatilized products thereof (Zn-l-CO) will more or less permeate the charge and the resistor thence passing to the hot inlets of the fissures and finally traversing throu h their constantly diminishing zones of imperature. The result thereof is that the zinc fume will condense and trickle down the side-surfaces of the fissures, as indicated by the arrow n, while he CO, as indicated by the arrows 0:, will pass into the atmosphere as such or it maybe burned to CO.

The liquid zinc formed in the fissures of the bottom, or hearth, may be conveniently collected in an underlying receptacle as 10, while that produced in the side-walls may be permitted to flow down their outer surfaces into collecting troughs, as 12 4.

It will be evident that the uniformity of the reaction, along the zone of the reaction, will be indicated by the discharge of zinc and CO from the numerous fissures or vents and thereby, as when the flow from the hearth-fissures becomes diminished, this will serve as a signal that inert residual matter in or beneath the resistor has accumulated. Yet, even if or when the fissures beneath the resistor become clogged, this would not necessarily terminate a period of opera tion, as the furnace may Sllll be run up to the maximum rate at which the side-walls will in themselves effectively condense. Consequently, there may be portions of a total period when all, or essentially all, of the condensation is efi'ected in the walls.

The charging of the furnace may either be of a character to effect continuous or intermittent operation, as circumstances may determine. Thus, if continuous the cover may be omitted in which case the side-walls or at least the upper portions thereof would be built up without fissures, thereby forming a shaft or trench in which an over-burden of charge-material can readily be maintained.

It is preferable that the width of each discharge slot or fissure should be comparatively narrow and that the aggregate crosssectional or flow-area of all the fissures shall bear a certain relation to the evolved volume of fume and as; for if the said area is too great a backow of air may result, producmg oxid, or if too restricted the pressure and velocity of discharge would be objectionable. The fissures should be of suiticient width so that in case they should become clogged they could readily be cleaned.

\Vhile this system of condensing has been described-as combined with a broken bed-ofcarbon resistor it is not necessarily restricted thereto in that it is applicable to various other modes of producing reaction by electric energy, as, say, by means of an overhead resistor acting u on the charge by radiated heat. The horizontal fissures may be inclined whereby to effect a more rapid outflow of condensed zinc.

I claim as my invention:

1. An electric zinc furnace havinfg a fume condensing system contained in tie lon itudinal side-walls and sole or bottom of t e reaction chamber.

2. An electric zinc furnace having at the sides of a bed-of-carbon resistor longitudinally extending walls between which is lo- (ated the reaction chamber and below the resistor a sole or bottom, each of the walls and the bottom being provided with a plurality of fissures the ends of which open respectively to the reaction chamber and to atmosphere.

3. A combined electric zinc furnace and condenser in which the longitudinal sidewalls and sole or bottom of its reaction chamber are provided with a plurality of spaces or fissures opening respectively to the said chamber and to atmosphere.

4. In the metallurgy of zinc an electric furnace having a carbon resistor adapted to support a superimposed charge of reacting material bounded by pierced walls in which zinc fume is condensed and from which the residual fume and gases escape directly to atmosphere.

5. An electric zinc furnace having a carbon resistor arranged so that a charge of reacting material can be placed on the resistor in physical contact with retaining walls which are provided with a plurality of horizontally disposed continuous condensing channels, ducts, slits or fissures that lead directly from the reaction chamber to atmos here.

6. n electric zinc furnace, a reaction chamber whose longitudinal side walls have portions that are contiguous to a bed-ofcarbon resistor and the zone of the chargereaction, and which are formed from tiles,

slabs, bricks or blocks, so laid or set as to produce a plurality of horizontally disposed continuous ducts, slots, vents, slits, or fissures in which the fume is condensed and from which residual fume and gases escape directly to atmosphere.

7. In the metallurgy of zinc an electric furnace havin therein a reaction chamber whose side wa is are rovided with narrow crevices or openings or condensing therein vapor to liquid zinc.

8. An electric zinc furnace provided with a bed-of-ca'rbon resistor supported on a wall having narrow crevices or'openings through which products of the reaction pass and in which the zinc fumes are condensed to liquid ZlIlC.

This specification signed and witnessed Signed in the presence of- RAOUL THOMAS, Hanson C. COKE.

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