US665427A - Electrolytic apparatus. - Google Patents

Description

No. 665,427. Patented 1an. a,.|9o|.

' w. T. Glass.

ELCTHULYTIC APPARATUS.

(Application filed Oct. 8, 1900.1

(No Model.; 2 Sheets-Sheet l.

pff/M' No. @5,4121 l Patented 1an. a, mol. l f w. Lamas.

'ELECTROLYTIC APPARATUS. I

. (Application led Oct. 8` 1900.\ (Numan.) 2 sheets-sheet 2. v

QM Wl/70 UNITED STATES PATENT OEEICE..

WILLIAM T. GIBBYS, OF BIIOKINGHAM, CANADA, ASSIGNOR, BY DIRECT AND vMESNE ASSIGNMENTS, 'lO-THE NATIONAL ELECTROLYTC COMPANY, OF

NEW YORK.

ELEcTRoLY-rlc APPARATUS.

` SPECIFICATION forming part of Letters Patent No. 665,427, dated January-8, 1901.

Original application filed September 9, 1895, Serial No. 561,911. Divided and this-application tiled October 8, 1900. Serial No.

32,44%. (No model.)

Togli/ZZ whom it, may concern: LBe it'known that I, WILLIAM. T. GIBBS, a subject of the Queen of Great Britain,residing at -luckingham,Ottawa county, Province of QuebecfOanada, have invented certain new and useful Improvements in Electrolytic Apparatus, fully described and represented in 'the'following specification and the'accompa- -n-ying drawings, forming a part of the same. ro My invention relates, in its broadest scope, to apparatus for use in all those electrolytic lprocesses `in which the ultimate product sought is formed by the actionupon each other of theproducts ofthe electrolysis, and

i5 morey particularly to the production of chlorates from the chlorids of alkaline and alkaline-earth metals, and has for its object' the construction of apparatus for use in such electrolytic processes and specially suitable for 'zo use in such production of chlorates. In these processes'thisdiiiculty has been encountered and has proved very serious.` Inasmuch as when a solution of mixed salts is submitted to'electrolysis every salt present is to a greater 25 or less extent decomposed, that saltthe production of which is the object of the process will as it accumulates in the liquid be itself to 'a certain extent decomposed by the action of the current, and a portion of the current 3o will thus be wastefully consumed. It has been usual to continue the electrolysis'until the saturatiouof the bat-h became such that crystallization would occur in the cell itself or in another receptacle into which the liquid was drawn off and allowed to stand for that purpose. As the percentage of the salt in the bat-h increased the percentage of current wasted in attacking it also increased and the A efficiency of the process diminished. While, 4o therefore, the eliiciency at the beginning might be good, thatat the end was very lo'w, and the average showed a very large percentage of loss. I have discoveredthat by making the liow ofl the liquid through the cell continuous it becomes practicable to remove the salt from the bath rapidly and Icontinuously and while its percentage is still small, and thereby to greatly reduce the quantity of current lost in uselessly decomposing it. Thus,

whereas the degree of saturation usually'here- 5o tofore employed in the practice of such processes hasv been upward of ten per cent., that employed in my process may be less than three4 per cent., and as a consequence the eicienc'y of the electrolysis is nearly doubled. l-Iav-` -ing removed the chlorate from theliquid, I vreplenish it with chlorid and return itin a continuous stream to the cell. I have also discovered that the chlorids of the alkaline and alkaline-earth metals can be electrolytically 6o treated between metal electrodes separated from each other only uy the solution and the necessary insulation-t'. e., without the use of a separating-diaphragm-with economy and success. Ithas been heretofore supposed that the hydrogen freed at. the cathode would reduce or prevent the formation ofthe chlorates unless the electrodes were kept separate by a diaphragm or unless the hydrogen we re consumed atv the cathode-as, e. f by an oxid 7o of' copper electrode. It has also been considered desirable tothus separate the liberated hydrogen and chlorin to prevent the formation of hydrochloric acid and consequent diminution of the amount of chlorate produced. I have, however, discovered in the course of my experiments that these reac tions do not occur in a substantially injurious degree when the' percentage of chlorate is kept down to a low percentage by a continu- 8o ons flow of the solution throughV the cell and thatv as a consequence I can employ metal kelectrodes in close. proximity to each other. This is a great advantage, since the use of a diaphragm largely increases the resistance of the electrolytic cell, and consequently7 the expense of 'the production, while the use of a non-metallic electrode, which will consume the hydrogen, is attended with disadvantages which seriously interfere with the economy 9o of the process. This discovery enables me to construct a cell having peculiar adaptations for my continuous process. I amenabled to place the electrodes in close and immediate proximity, and thus to use a current of large ainperagel and low voltage. The cell vin which these electrodes are containedis necessarily of small, cnbical capacity, since the latter cannot be greater in proportion to the cleetrodesnrface than-will properly feed the electrodes by the action of diffusion, and therefore it is not adapted to the old disconuous process. In t-lie first place, its capacity is so small that the iilling of the cell, the application of the current, and thc emptying and the reilling of thc cell would entail inconvcniencewliieh would make such use almost if not wholly iiiipi'acticable, while if the solution passes through the cell in a continuous iow its capacity is ample.

Another very important advantage secured by the small size ofthe cell and the lange aniperage or density of the current I am enabled to use is that Icaii produce all the heat necessary to raise the temperatuye to the proper point for the decomposition of hypoclilorites by the action of the current itself. lleretofoi-o it has been usual on account of the large capacity of the celleniployed in the manufacture of chlorates to supply this temperature by means of heat from an external source. This is very diilicult to do, practically because of the necessity of using apparatus for conveying the heat to the solution which will be resistant to the action of chlorin. In this connection, again, the continuons flow of the solution through the cell is ol' great consequence, for the reason that the large amount of current I am enabled to use in the small cell would, if the electrolysis were conducted in the usual discontinuous manner, heat the bath much higher than is permissible, while the continuous iow of the solution reduces and limits the development of heat to such a degree as is desirable for the process-namely, within the limits of 90 to 200 Fahrenheit, the preferable temperature being from 110J to 1200 Fahrenheit. With this construction of cell and with a continuous llow l am enabled to use a current of two to four (preferably three) amperes per square inch of electrode-surface, which very greatly increases the capacity of the plant in proportion to its size over anything heretofoi-e accomplished.

Another important advantage secured is that Iam able to control and regulate the temperature olf the solution in the cells by regulating the llow of the solution, `vliicli as it enters the cell is cold and causes an over- 'llow of the hot solution. This is a much more convenient means of regulating the temperature than by regulating the supply of external heat, on the one hand, or than by regulating the density of the current used, on the other hand, and this advantage is of greater value where a battery of cells such as is especially adapted to my process is employed than where single cells are used, for this reason that where a single current is dircctcd through a battery of cells if it were attempted to regulate the heat in the cells by changes in the density of current all the cells would be effected by each change, whereas the temperature of the solution in different cells may be different,owing to different conditions ol' locations of the cells in the battery or diler ent internal conditions in the cell or in the supply and delivery pipes leading to and from each cell. The flow of the-solution through each cell, however, can be separately and conveniently controlled so as to properly limit and adjust the temperature in each cell separately from and indepeiiden tly ot the others.

It is necessary in the cells For the production'of chlorates to use as an anode a mate-v rial which is substantially resistant to the action of chlorin-as, for instance, platinum. The costof this metal or equivalentmaterial,

however, makes impracticable the use of heavy sheets as electrodes, and the highvresistaiiceof platinum also infits it for use alone as an anode. It is also extremely difficult to use thin sheets of platinum as electrodes, owing to their tendency to bend and warp,and consequently short circuit. It is also disadvantageous to use compound plates made up of a cheap metal,which would if used alone be subject to disruption in the presence of chlorin plated or coveied with resistant material, as platinum, for the reason that it is diilicult to make such covering at the angles of the plate impervious to the action of chlorin, and such'plates when used have been found to have less durability than is desirable. Furthermore, whatever the material of the electrodes the use of the usual connecting-rods causes much trouile and expense, since they are both inconvenient in themselves and continually liable to disintegration through accidental contact with the chemicals. I have overcome these difficulties by using for one side ofeacli cella plate of cheap metal-as, for instance, lead-faced with platinum or other substance substantially resistant to the action of chlorin, causing the plate and facing t'o project beyond the other parts of the cell which iiiclose the solution, so that only the :plain face of the plate will be exposed to the solution, andemploying this platinum face as the anode of a single pair of electrodes contained in the cell, this being my preferred construction, it being understood that I do not limit myself to it. 'lhis .facing of'platinum or other resistant substance canbe iliade very thin without disadvantage, since strength and rigidity are supplied to it by the metal backing, which cannot be reached by the solution. rlhe diilieulty of making connections is also avoided, since these are made through the wall of the cell, and the 4cell'or cells being preferably clpsed and arranged as described chemical attack upon parts of the circuitotlier than the electrolyte is avoided.

1 have also devised a feature of construction which practically overcomes another difficulty ordinarily encountered in such processes-viz., polarization of the cathode caused by the adherence thereto of hydrogen bubbles. Ihave ascertained that an electrode composed of vertical wires or metallic rods possible contact with the cylindrical surfaceA of the wires or rods. Consequently they do not adhere thereto, but roll up the wires to the top of the cell and there escape. In order to obtain the best results, these reds should be of metaland of small diameter,sincc there is no other material than metal which is equally suitable for the purpose, and it the diameter ot' the rods be large the surface approximates to a plane surface and has a tendency to hold the bubbles lof hydrogen. I

have found the best results to bc secured byv a small rod or wire, by which I mean a rod or wire having a diameter less than a quarter of simplify and protect the connections I pro- Yat.\the two extremities of the series.

vide in each cell an interior metallic connection between each cathode, and this rear wall of the cell, as by Alining the interior ot' the cell between the two in whole or in part with metal or making this part of the cellentirely of metal. providing mere conduct-ing connections between the cathode and the rear wall. It will of course be understood that suitable insulation is provided between each pair of electrodes. This may be accomplished in any suitable manner--e. g., when the cellis otherwise all of metal or lined with metal or provided with metallic connections, as above suggested, it may be conveniently effected by means of au insulating-gasket entirely separating those parts of the cell connected with the two electrodes, respectively, and held in place by a proper fastening or clamp placed upon the cell or series of cells. By this construction I secure a unit for use in constructing a series of cells, such unit containing an anode and a cathode belonging, respectively, to adjacent pairs ot' electrodes, whichunits when combined with interposed insulatinggaskets constitute a series of' cells -in which the path of the current lies entirely through the electrolyte and the cell\\'alls,exterior connections being wholly dispensed with except This construction has great advantage in convenience and durability.'

In the drawings annexed, Figure 1 represent-s a vertical cross-section of a series of cells made in accordance with my invention and set up for use. Fig. 2 is a side elevation of one of the cells seen on line 2 2 of Fig. A1, the point of view bei-ng to the left of Fig. 1; and Fig. 3 is a diagrammatic sketch; of the cells, coolingchambers,pump,and replenishing-vat as the same may be used in connection with a continuous chlorate process.

I will first describe the construction of my'.

cell.. Each cell consists of a frame A, (shown their usev is not essential to my process.

in vertical cross-section in Fig. 1 and in side elevation in Fig. 2,) which may be of metal, butwhich I prefer to make of wood, with metallic or other conducting resistant lining B, as shown, or which may be of other material not subject -to attack by the solution. Upon one side of this frame are attached the rods or wires C, constituting a cathode, and on the otherside a metallic plate D, faced with platinum E, constituting an anode. The cathode may be of copper, zinc, or other suitable metal, as likewise m ay be the lining B and the plate D. I prefer copper for the cathode and lead for the lining and the plate. It should be observed that it is not essential that the lining B be continuous over the entire surface of the frame A, it being sufficient if conduct-ing connection is made between the cathode and plate D and the material of the frame if subject'to attack by the solution is suit-ably protected from the action of the contents of the cell. The successive frames are insulated from each other by means of gaskets F, of any suitable insulating material, which may be used to form a tight joint bet-Ween successive frames. These gaskets are substantially of the same vertical cross-section as the frames'.

Supply-tubes G are provided for the -introduction oi' the solutionto be subjected to the electrolytic process, and Vents H are provided at the top of the cells for the discharge thereof and of the liberated gas. In order that the cells maybe kept always full, these vents are placed just above the inside level of the top of each cell, the frame being recessed for that purpose, and this recess is continued inward, as shown in dotted lines in Fig. 2, in order to permit access of the solution to the vent.

When erected for use, the frames are placed side by side, with a gasket between each t'wo, as shown in Fig. 1,and are preferably clamped together by means of two end plates J K, connected by bolts L.` The plates .I K are separated from :the cells by insulating material.

`The left-hand cell of the series is closed by a simple plate m, faced with platinum. The platinum face on the metal back of the righthand cell is omitted. Each pair of electrodes is separated by the corresponding gasket. To prevent short-circuiting by bending of the wires, horizontal` insulating-rods O are pro- Videdvbetween the electrodes, these rods being supported by curved portions of the wires or other suitable support,or other appropriate insulating means Vmay be employed.

Referring now to the diagram, Fig. 3, Preplresents the electrolytic cells overflowing into cooling-chambers Q Q, which may ,be one, two, or more in number. These cooling-chambers are shown as provided with cooling-coils R.. The-use of such coils is an advantage, since it secures theprecipitation of a greater proportion of the chlorate in solution; but S is a pumpfor returning the depleted solution to the replenishing-vat T, where it meets a IOO `p5MIprth'e"metal-lined frames A, but may emfresh supply of chlorid and is fed by the siphon the anode.; 'Other suitable materials substan-4 X or other connection again into the cell. vtially resistant toI the action of chlorin may The ow of the solution through the cells is, as I have stated,l continuous, and the rate of flow and quantity of electric current used are so proportioned that the solution as it. leaves the cellshallhave a small percentage of chlorate"`Tlii`s percentage is preferably lless than three per/centi, and Ihave found the results to be excellent when it was as low as one 4and onhalf to one and three-quarters per cent. The capacity of the cell advantageous for use in my'proc'essis from tyvo to four cubicinches` per squareV inch of electrodesurface.' If a greater amount -of liquid in proportion to the electrode-surfaceis present in the cel-l, it is diicult to maintain the req. uisite degree of heat by the action of the current, and the application of external heat to the cell is diicult and expensive, and, further, the vpresence of a larger amount of solution than that indicated interferes with the proper diffusive action in the' cell. While these dimensions of thercll are preferable z5 when cells areused in connection with my improved chlorate process, itlwill be understood that Ido not limit myself to these dimensions."

Bythejerm close proximity of the electrodes I intend to Yindicate the ciosestproximity which it is 'practicable to obtain between insulated electrodes-as, for instance, onesixteenth to one-eighth of an inch. Ido 'not,"' ll .wever, limitmyself to such close proximity, except in thtse claims in which the electrodes are specified as being in close proximity. v'

It is an advantage that the flow of the liquid should be continuous through thecrystallizing-chambers and the replenishing-vat back tothe cell, aswell 'as throu'gh the cell itself; but'continuous ii'ow is not essential to this part ofthe process.

I do not of course limit myself to any special dime'siplls of apparatus; butI may mention that Ihave found a 'convenient' size for the cells .to be4 twenty-six by eighteen inches', with a' thickness of three inches, the electrodes` being aboutone-eighthf of an inch .5o aparts.

` The-.action 0f. the' apparatus as above described is that adapted to the manufactiref potassium chlorate and other chlorates which f "are .lesssoluble in water than the correspondingvchlorids In the manufacture of sodium .chlorateandof suoli other chlorates as'are l'piore soluble than the corresponding chlorids xhe separation of the chlorates is effected by causing the chlorid to'crystallize in the coolo -igig-vatsgand the-subsequent evaporation of IAQ-c. chlprate solution, a continuous flow of @celectrolyte beingmaintained .through the 'lectrolytic cell .or cells.

Yzothersuitable material. Neither do be used for this purposewithout departing from my invention in other respects.

While I have described the plates D as permanently attached to thev frames, I dol not conne lmyself to such construction. These nection with the cathode when the cells are set up.

While I- have shown my cells as closed, and such a' construction has advantages, I do not .limit myself to closed cells. If desired, the frames A may bejso constructed that the cells shallhave open or partially open tops.

While I have referred Iparticularly to the sides ofthe cell as made of metal, it is of course to be understood that au equivalent construction would be the use of other material lined with metal or with other conducting resistant material. So, also, the frames A may be made of solid metal instead of other material lined with metal, audit is not essential that t-he lining should cover the whole of the frames if the material of the latter is not such as would be attacked by the liquid. If

attack, their entire inner. surface may be exposed aiid a mere conductinggonnection be provided between the cathed'ee'and the rear wall.

I intend to claim the structure of cell shown when used for the prod uction of chlorates and also when used'for any other purpose.

plication, Serial No. 561.,9l1,`fled September 9, 1895, in which is claimed the process o f obtaining chlorates described herein.'

' What I claim isl. An electrolyt-ic cell having two electrodes connected respectively tothe positive and negative poles of a source of electricity, and the negative electrode consisting` of vertical metallic wires or rods of a diameter less than one-fourth of aninch, substantiallyas sot forth. Y

' 2. An electrolytic cell in. which one of the 4the presence of chlorin interiorly faced with a 'substancesubstantially rosistantto the action of chlorin, the same constituting one "tive pole of a sourceof electricity, and in which the other electrode consists of vertical wires or rods of suitable metal properly supported in the cell, substantially as set forth. 8. A pair. of` electrodes o f which one elecfaced with a substance substantially resistant to the action o f chlorin while the Aotherelctrode consists of vertical rods or wires, shortci rcuitingbetween thev rods'and the plate being preventedby rods of insulating substantially asset forth.'

Ibnii'neftnpelf the use of platinum for plates may be made separable from the frames if suitable provision be' made for securing a tight joint and maintaining the electrical c'onthe material of the frames is' noty subject to' This application forms a division of my aptrode consists of 'a'plate of suitable metall IOO IIO

cell-walls is of metal subject to disruption in electrode and being connected with the posivx' 3o material,

. .4. Anelectrolytic oelt'whereo'f one wall of' or rods of suitable metal properly supported in the cell, said electrodes being secured against short-circuiting by rods of insulating material between them, substantially as set forth.

5. An electrolytic cell whereof a-Wall of metal interiorly faced with a substance substantially resistant to the action of clilorin constitutes one electrode, and the other electrode is constructed of verticalwires or rods .0f suitable metal, properly supported in the cell and duly insulated from the first-named electrode, substantially as set forth.

. l G. An electrolytic cell having two parts of conducting material separated from each other by insulating material,one of these parts ,constitnting one of the electrodes'of the cell,

and the other electrode being supported AWithin the cell and conductively connected with the other part, ,substantially as set forth. 7. A series of electrolytic cells, each cell made of two parts of conducting material insnlated from each other by insulating material, one of said parts of each cell constituting one of the electrodes of the cell and the other electrode of the cell being supported Within the cell and in conducting connection with the other part of the cell, whereby when the cells are associated each electrode (except the terminal electrodes) is in metallic connection with an electrode of opposite sign in the adjoining cell through the cell-walls, substantially as set forth.

8. An electrolytic cell in which one of the cell-Walls is of metal subject to disruption in' the presence of chlorin, interiorly faced with a substance substantially resistant to the action of c'hlorin, the lain surface of the facing only being expose ptoA the liquid, the same constituting one electrode and being connected with the positive pole of a source of electricity, and inwhich the 'other electrode consists of vertical wires] o rods properly sup,- ported in the cell and connected with'the negative pole of a source of electricity, substantially as set forth. y i l 9. The combination of a series of frames A, each, frame provided with wires C and A platinum or equivalently faced plates D, substantially as set forth.

10. The combination of the frames A,wires C, platinum or equivalently faced plates D, gaskets F, and means for holding the frames together, substantially as set forth.

In testimony whereof I have hereunto set my hand in the presence of two subscribing witnesses.

WILLIAM T. enses.l

Witnesses: v' i F. J. BROWN, ARCH G. LOBY.

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