US1828004A - Electrolytic cell curtain - Google Patents

Description

Oct. 20, 1931. L. E. WARD 1,328,004

ELECTROLYTIC CELL CURTAIN Filed June 10, 1929 2 Sheets-Sheet 1 INVENTOR SECTION ON A'5, F/G.Z. BY

Jam mwayl.

ATTORN EY Oct.'20, 1931. L. E. WARD ELECTROLYTIC cm curmm FiledJune 10, 1929 2 Sheets-Shea! 2 INVENTOR 1 BY 6. WM Jfimnqu; ulowufd ATTORNEY Patented Oct. 20, 1931 UNITED. STATES PATENT OFFICE} Louis E. wAnD, or MIDLAND, MICHIGAN, AssIGNon 'ro THE Dow cmnncu. comm,

OF MIDLAND, MICHIGAN, A CORPORATION OF MICHIGAN nnncrnonr'rrc CELL CURTAIN Application filed June 10, v192e, Serial No. 369,683.

' 5 adapted for use in separating metallic magnesium and chlorine gas produced by the electrolysis of a fused saline bath containing mag-- nesium chloride.

' Owing to thehigh temperature to which I such a curtain is exposed, the corrosive action of chlorine and other anodic products and further to the fluxing or erosive action of the fluid hot metal upon ceramic ware, in general, and still further to the necessity that the curtain have electrical non-conductive property, the choice of material for-such a curtain is somewhat narrow and the details of construction require careful design.- Hefractory material such as fire-clay or brick shapes is customarilyemployed and because such material suflers erosion, corrosion, or

breakage it is essential that the details of design shall permit the easy substitution of new'parts to replace those no longer serviceable. It maybe stated, in general, that such pieces of large size are relatively more expensive than those 'of small size, are more diflicult to pack, ship, unpack, and store without breakage and are morereadily broken when handled in a replacement operation. Small pieces, on the contrary, are more cheaply made, more easily packed and transported, easily stored in small space, and can be handled witha minimum of breakage and loss. I haveinvented a curtain'composed of a plurality of suitably shaped plates of simple design and small size including means to sup port said plates'in the cell permitting the easy removal and replacement of any single piece even without suspending operation 0 the cell during such repairs. j

To'the accomplishment of the foregoing and'related ends, the invention, then, consists of the parts and assembled structure hereinafter fully described and particularly pointed out in the claims, the annexed drawings and the following description setting forth in detail certain forms of the invention, such disclosed forms illustrating, however, but some of the various ways in which the principle of the invention may be used.

In said annexed drawings Fig. 1 is a vertical cross section through an electrolytic cell adapted to the electrolysis of a fused bath, such asone containing magnesium chloride for the production of magnesium metal and chlorine. Fig. 2 is a top plan view of the rectangular shaped sectional curtain shown in Fig. 1. Fig. 3 is a. vertical cross section on AB of Fig. 2 at right angles to that of Fig. 1 showing the same rectangular sectional curtain and details of support for the same. Fig. 4 is a part plan view eta circul'ar sectional curtain. Fig. 5 is a part plan view of another circular curtain. Fig. 6 is a side view of one of the hooked bricksemployed in Figs. 1, 2, and 3 as supports for the curtain plates. Fig. 7 is an edge view and Fig. 8 a side view of a segment of the. curtain in Fig. 2. Fig. 9 is an edge view and Fig. 10 a side view of another form of segment or plate member of a curtain. Figs. 11 and 12 show a variety of forms of sectional curtain plates and supports for" same. Fig.

13 shows a still further variation in a, curtain support. Fig. 14 shows in' a horizontal-cross .section through a curtain a modification in form involving overlapping of one section upon another. Fig. 15 *is' a similar cross section showing a corrugated form of sectional curtain. Fig. 16 is a plan view of a hooked brick support for sections or plates of a circular or curved curtain. Fig. 17 is a part plan view of a circular curtain including the brick shown in Fig. 16.

My curtain may take a wide variety, of iforms em loying also a like variety of forms of suppo and may, in general, be applied to a variety of electrolytic cell constructions.

I will describe it as applied to the cell concated in the plan Fig. 2 and the correspondng cross sectioIrFig. 3. Such anodes depend in the bath fromabove being preferably supported from adjustable hangers permitting 1 number of which may be set in line as indithe surface of the bath in the compartment 7 motion in a vertical direction, removal from the bath, reinsertion therein and for varying the depth of dip in in the bath.

In the type 0 ce 1 illustrated, the pot is provided with an inverted trough 3, adapted to trap liberated metal rising from theactive cathode surface 4 of pot 1. Such metal is shown at 5. A provision may be advised- 1y made to lead such trapped metal to a collecting or gathering zone orwell for eas access and removal. The curtain 6, preterably composed of refractory plates, is hung from a series of bricks7 composing a part of the superstructure of the setting. The cure tain 6 will be composed of a plurality of plate-like pieces arranged in juxtaposition edge to edge to form an enclosure about the anode or a out a plurality of anodes as the case may be. Cover slabs 8 resting upon suitably disposed brick work of the superstructure inclose a space 9 into which the chlorine gas or other gaseous products are directed by the sleeve-like flue formed by the curtain. The curtain not only serves as a. means of separating the anodic gas from the metal, but it also covers those portions of the pot surface from which liberated meta. may not directly enter the collecting trap, thereby restricting the liberation of the metal thereon to a minimum whereby i nci dental losses are reduced. In the particular cell illustrated, the bath level will be at or about 10 and a clearance space will be desirablyleft between the faces of the trap 3 and the curtain to permit the small amount of metal liberated on the outer faces of the trap to rise freely to the surface of the bath, whereby it will be removed from immediate contact with the lower portions of the cur- I tain. Provision may be made as understood in the -art to remove such floatlng metal from 11, as by skimming or causing the metal to float to a collecting zone, so as to avoid its.

erosive action upon the curtain.

It will be seen from Fig.2, which is a plan of the curtain of the cell shown in Fig. 1 and employing four anodes in a row, that the curtain plates 6 form continuous rows along two sides of the rectangle inclosed by the curtain and the end lates 6' close the ends of the rectangle. arious methods of supporting the curtain plates may be employed a number of which will be described ereinafter.

Fig. 4 is a part plan view of a circular or ring shapedgcurtain, here shown, composed of plates indicated a 6. 6', 6-, 6" and 6"". The support for these plates is shown in Figs. 9 and 16. Fig. 5 is a part plan of another circular curtain showing as in Fig. 4 a vaview of a hooked brick showing, in general,

one form of support folthe curtain plates.

Figs. 9, 10 and 17 are vertical cross sections,

face and plan views of plates and supports for a circular curtain showing, in general, a form of plate and support. Fig. 16 shows the hooked brick of Fig. 9 in plan. Such brick is provided with a sloping peg-like projection onto which the curtain may be slipped to engage suitable notches or holes' therem. Such peg-like projections and the notches in the plates mayhave a variety of forms, a number of which are indicated in face view in Figs. 11 and 12. The forms of notches shown in Fig. 11 are adapted to the side edges of the individual curtain plates,

curtain plates in a. manner not only to support same in a vertical direction but to retain the slab in position against small forces tending to push it 01f the support.

I find it preferable to have the peg-like supports slope as indicated or to provide them with a notch shaped form as shown in Fig. 13 in whichthe peg 12 has an up- Ward projection at the outer end and the, plate 6 has a corresponding downward projection in the notch enabling the hook to retain the plate. Many other equivalent forms of curtain plate supporting pegs or the like mi ht be shown.

eferring to Figs. 11 and 12, ears 13 may be provided, pierced with holes, or other equivalent tabs or lugs may be added to the plate suited to enable the easy grasping of a hot plate with such a tool as will permit handling it for removal and replacement in a hot cell under operation. A hole, 15, adapted for the insertion of a handling hook is shown in Fig. 8 and two such are shown in Fig. 3. The abbutting edges of the plate may obviously have various angular relations to the plate faces. A corner of a curtainmay be turned in a variety of ways, one of which is shown 'in Fig. 2. Alternative ways of turning a corner such as in Fig. 2 may use a longer supporting peg, projecting beyond the face of the plate 6, and the plate 6 will be carried on the portion of the peg projecting beyond the anyfssuch forms are in relation one to another such as to form a plurality of correctly placed supports for the curtain members. I then hang the curtain members from the supports so provided, one at a time or several or all at -a time, as may be convenient, adjusting same to positions in juxtaposition each to its adjacent member to I form a partition or curtain dipping in the bath between the surface areas of the bath through or from which the anodic and cathodic products of electrolysis pass on their Way out of the bath.

When it becomes necessary for any reason to substitute a new plate for one in service,

1 provide such plate in a handy location to the Y preheated one. The manipulation will, of

course, depend upon the character of the support and the like character of the engaging contour of the plate but, in general, the fresh plate will be lowered into place, slipped onto the hook and there adjusted in position in alignment With the adjacent plates. I thereupon replace the cover slab. In order to avoid escape of anodic gas into the room enough suction will be carried upon the conduit 4, in Fig. 1, through which the anodic products are withdrawn, to draw a current of air into the cell through the opening made by removing the cover slab during repair operations.

My invention isapplicable to advantageous use in both large and small scale operation.

It is particularly applicable in large scale v I burning? packing operations employing a plural'ity of anodes in a large cell. A sectional curtain for such a cell may be readily constructed of small pieces-or plates of the characterdescribed to enclosure or partition for leading the anodic gas to the, outlet, for covering exposed portions' of the pot upon which it is desired to restrict cathodic action, and for separating the floating metal from the anodic products.

Such a curtain may be constructed far more cheaply and safely than a large sized single piece curtain and renewals will be confined to the replacement of small pieces for any one breakage whereas when large single piece curtains are used, breakage at a single point will require the substitution of a new piece of large size and cost; Not only are small refractory pieces more cheaply made than large ones but they suffer less breakage in drying, shipping, and storage. They require less oxing and packing materials for shipment, less storage room and less labor in handling, and are in many respects highly advantageous relative to large sized pieces. I have found the disadvantage incident to the discontinuous'character of the curtain, due to the more or less imperfect joint obtainable in actual practice between the ad ed verticallyedge to edge therefrom and held form a rectangular, oval, circular, or other j partmon Wall or curtam' sectional partition wall or curtain.

joinsingplate edges, to present no serious dif portion is liberated upon the surfaces of the,

metal adjacent to the curtain to become later liable to passage in part throu h the curtain joints into the anodic gas cham er before removal as metal product.

I have described my invention employing refractory material for the curtain plates. Other materials are, however, available such as ceramic materials, sintered or fused magnesia, alumina or the like, resistant to the particular bath employed, and I conceive my invention as covermg the use of any suitable refractory material for a sectional curtain.

Other modes of applying the principle of my'invention may beemployedinstead of the one explained, change being made as re-' gards the means and steps herein disclosed, provided those stated by any of the'followmg claims or the equivalent be employed.

I therefore particularly point out and dis-- tinctly claim as my invention 1. Inapparatus of the character a plate-like curtain member of refractory material adapted to engage a horizontally disdescribed, 1

posed member of the'cell superstructure so as to be suspended vertically therefrom, and capableof being assembled edge toedge with other like plates to form a continuous sec- 2. In apparatus of the character described, a plate-like curtain member of refractory material adapted to engage a peg-like extension projecting laterally from a horizontal cover member and thereby. being suspended vertically therefrom, and capable of being assem- 'bled edge to edge with other like plates to form a continnous'sectional partition wall or curtain. y

3. In apparatus of the character described,

a plate/like curtain member of refractory material having a notched contour adapted to engage a peg-like extension projecting laterally from a horizontal cover member and being thereb suspended vertically therefrom," and capab e of being assembled edge to edgewith other like plates to form a continuous 4:. In apparatus of the character described, a sectional curtain comprising a plurality 'of plate-like members of refractory material adapted to engage with horizontal members of the-cell superstructure so as to be suspendc. in place thereby to form a laterally bounded enclosure.

5. In apparatus of the character described, a sectional curtain comprising a plurality of plate-like members of refractory material adapted to engage with peg-like extensions projecting laterally from horizontal cover members, being vertically suspended edge to edge therefrom and held in place thereby to form a laterally bounded enclosure.

6. In apparatus of the character described, a sectional curtain comprising a plurality of plate-like members of refractory material having a notched contour adapted to engage with peg-like extensions pro'ecting laterally from horizontal cover mem ers, being suspended vertically edge to edge therefrom and held in place thereby to form a'laterally bounded enclosure. 4

7. In an apparatus for the electrolysis of a fused salt bath, the combination of a vessel to contain such bath, an anode depending centrally in said bath, horizontally disposed cover members supported upon the rim of said vessel and extending inwardly to cover the outer part of the bath surface While leaving a central opening surrounding and spaced away from said anode, a plurality of platelike members of refractory material sus pended edge to edge from said cover members within said opening to form a continu ous sectional curtain circumscribing said anode and dipping below the surface of said bath.

'7 material adapted to engage said pegs and suspended therefrom edge to edge forming a continuous sectional curtain circumscribing said anode and-"dipping below the surface of said bath. J

9. In an apparatus for the electrolysis of a fused salt bathythe combination of a vessel to contain such bath, an anode depending centrally in said bath, horizontally disposed cover members supported upon the rim of said vessel and extending inwardly to cover the outer part of the bath surface while leaving a central opening surrounding and spaced away from said anode, said cover members being provided with peg-like extensions projecting laterally within said 0 ening, a plurality of plate-like members 0 refractory material having a notched contour adaptedto engage said pegs and suspended therefrom edge to edge to form a continuous sectional curtain circumscribing said anode and dipping below the surface of said bath.

10. In an apparatus for'the electrolysis of a fused salt bath, the combination of a vessel to contain such bath, aplurality of anodes depending centrally in said bath, horizontally disposed cover members supported upon the rim of said vessel and extending inwardly to cover the outer part of the bath surface while leaving a central opening surrounding-and spaced away from said anodes, a pluralityof plate-like members of refractory material suspended edge to edge from said cover members within said opening to form a continuous sectional curtain circumleaving a central opening surrounding and spaced away from said anodes, said cover members being provided with peg-likeextensions projecting laterally within said opening, a plurality of plate-like members of refractory material adapted to engage said pegs and suspended therefrom edge to edge to form a continuous sectional. curtain circumscribing said anodes and dipping below the surface of said bath.

12. In an apparatus for the electrolysis of a fused,- salt bath, the combination of a vessel to contain such bath, a pluralit of'anodes depending centrally therein, orlzontally disposed cover members supported upon the -rim of said vessel and extending inwardly to coverthe outer part of the bath surface while leaving a central opening surrounding and spaced away from said anodes, said cover members being provided with peg-like extensions projecting laterally within said opening, a plurality of plate-like members of refractorv material having a notched contour adapted to engage said pegs and suspended therefrom edge to edge to form a continuous sectional curtain circumscribing said anodes and dipping below the surface of said bath.

Signed by me this 8th day of June, 1929.

. LOUIS E. WARD.

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