US1365032A

US1365032A - Electrolytic apparatus

Info

Publication number: US1365032A
Application number: US231534A
Authority: US
Inventors: William E Greenawalt
Original assignee: Individual
Current assignee: Individual
Priority date: 1918-04-29
Filing date: 1918-04-29
Publication date: 1921-01-11
Anticipated expiration: 1938-01-11

Description

W. E. GREENAWALT.

ELECTROLYTIC APPARATUS.

APPLICATIONv FILED APR. 29, 191s.

1,365,032. Patented Jan. 11,1921

2 SHEETS-SHEET l- MMM.

W. E. GREENAWALT. ELECTROLYTI APPARATUS. APPLICATION man APR. 29. 191s.

15365032. Patented Jan.11,1921,

2 SHEETS-SHEET 2- 55 MM 50 W//l/ 0m@ Z3 52 Y' UNITED STATESPATENroFFicE.

WILLIAM E. GREENAWAL'L` QF DENVER, COLORADO.

ELECTROLYTIC APPARATUS.

To all whom t may concern:

Be it known that I, WILLIAi/r E. GnnnuA- WALT, a citizen of the United States, residing in the city and county of Denver and State of Colorado, have' invented certain new and useful Improvementsl in Electrolytic Apparatus, of which the following 1s a specification. c This apparatus may be regarded as a modiication and a continuation in part of that de scribed in my co-pending applications, Serial No. 16,962, iled March 25, 1915, and Serlal No. 145,884, filed February 1, 1917, and represents an ,improved apparatus" for carryingout the processes described in my co-pending p/ocess applications, Serial No. 15 583, led arch 15, 1915: sei-iai No. 140,112.8, ined Jau. 5, 1917, and SerialNo. 185,652, iled August 1.1, 1917, although it is not intende to limit it to any particular use.

In the electrolysls of impure copper solutions," as for example those obtained from leaching' ores with an acid sulfate solution,

there is always .present iron sulfate, which injuriouslly affects the operation. Ferrous sulfate in the electrolyte is not particularly harmful, but the ferrie sulfate is highly detrimental. The object of this invention is, first. to cause effective deposition -o'f the' copper from an electrolyte containing lsalts of iron;'second, to cause effective reduction of the ferrie. salts formed by the electrolytlc action third, to cause effective oxidation of the ferrous salts and consequent depolarization at the anode.

If a solution of copper sulfate, containing ferrous sulfate is clectrolyzed, copper is deposited at the cathode while sulfuric acid and ferrie sulfate are'produced at the anode,

. as shown by the following equations:

' 1. (uSO4-l-H2O-l-Electrolysis:

3. 01+Fp,(so,)Penso,,raresoa The loss of cl'iciency dueto this cause is tions.

Specification of Letters llatent.` Patented Jan, 11, 1921. Application mea April 29, 191s. serial No. 231,534." i

ferrie salts .in the electrolyte, and under certa1n conditlons may be quite large; In agmore' or less proportional to the amount of gravated cases the loss of efficiency may bc hydrogen sulfid, or copper sulfid, then acid is regenerated, and the iron in the electrolyte', being reduced to the ferrous condition, loses its ability to combine with the deposited copper, as shown by the following equatlons: 4:' Fez (SO4)3`l`S02i`2II2O:

lyte by means of sulfur dioxid depends, first, upon@ the temperature of the electro-v lyte, and second, upon :it'fitation The effec tive reduction of the erric compounds in the electrolyte depends lprincipally upon the temperature. On thel other hand, sulfur dioxid is only slightli'-,sfoluble in hot soluv Toefectivelxflliarmonize these various conditions, I have devised the'apparatus, shown in the accompanying drawings, vin which Figure 1 shows a general longi* tudinal section: Fig. 2, a detail cross section: Fig. 3, a detail longitudinal section: Fig. 4, a detail longitudinal section of electrodes and conductors showing the electrical connections: Figs. 5 and 6, adetail cross section, and a detail longitudinal section,

respectively, of a modified apparatus: Fig. 7 a detail plan `of Fig. 1, showing the electrodes and electrical connections: Fig. 8, a detail cross section showin the electrodes and electrical connections: ig. 9, `a detail of the rotary spraying device: Fig. 10, a detail of the stuiling boxabout the electri- -cal conductors: Fig. 1l, a detail of the cover of the electrolyzer showing the method of attaching the lead lining to the sheet steel.

In the drawings, 1 is an electrolytic tank, having a removable cover 2, communicating with a gas generator 3, and adapted to contain the electrolyte` and the

vertical electrodes

4 and 5, resting on submerged conducting

bars

15 and 16 at the bottom of the tank. The electrolyte Hows into the tank through the pipe 9, and Hows out through the pipe 10. The gas from the gas `generator, with which the electrolyte is treated, Hows in through pipe 21, and the excess, if any, Hows out through pipe 22. Above the electrolyte, and within the hood or cover, is a spraying device, consisting of a shaft 6, rotatedin bearings 8, when driven by the motor 11, and having mounted on it disks '7 which are partially immersed in the gas and partially submerged in the electrolyte, and which spray, or atomize, the liquid into the gas confined over it while at the same time submerging some of the gas in the liquid, when rotatedat a proper speed by the motor 11.

The electric current is supplied to the electrodes by means of the terminals 24 and 25, and the conducting

bars

15 and 16 in the bottom of the tank. Electrical connection is made with the electrodes by letting the electrodes rest on the conducting bars. The electrodes are held in position by the side pieces 17, which may be of wood, and having saw-cuts, or grooves, 18, to receive the ends of the electrodes. In this way the electrodes are Hrmly secured and maintained parallel. The arrangement for the insulation of the electrodes is shown in Figs. 4, 7, and 8. One end of the electrode rests on its corresponding conducting bar, while the other end rests on an insulation plate. which, in turn, rests on ,the opposite conducting bar. Thev electrode 4, for example, rests on the conducting bar 15, making electrical contact therewith, while the other end rests`on the insulation plate 19, which in turn, rests on the conducting bar 16. Similarly the electrode 5, rests on the conducting bar 16, making electrical Contact therewith, and is insulated from the opposite conducting bar 15, by the insulation plate 20. A current, therefore, entering through the bar 15, and being insulated from the bar 16, would pass through the electrolyte from the electrode 4 to the electrode 5, and then to the conducting bar 16 on which electrode 5 rests and with which it is in electrical contact, while the electrode 4 is insulated from the bar 16. In this way, the total current enters the cell through the bar 15, and passes from all the electrodes 4 to the electrodes 5 through the electrolyte, and out through the bar 16. The conducting

bars

15 and 16 are preferably` made of copper, with a lead casing 37. he copper gives the desired conductivity, while the lead resists the action of the acids and variable valent salts better than the copper. The conducting bars are preferably carried through the ends'of the cell through stuffing boxes 43; in this way the tank can be kept from leaking, and electrical connection with the conducting bars made outside of the cell. The insertion and removal of the conducing bars is also facilitated in this way. The stufng box may be made ferro-silicon, copper, or antimonial lead. The anodes, 4, are held in position by wooden strips 17, which, in turn, are secured to the tank by the pins 48, or possibly, simply by wedges. If desired, for additional security against current leakage, the ends of the anodes 4 may be insulated by the insulation 29, as shown in Fig. 7. In copper deposition'there is danger of the copper being deposited in such a way as to make the removal of the cathodes very difficult; to overcome this a special side strip 27, Fig. 7, is arranged with a groove to take the ends of the4 cathode, and the strip then Htted very loosely to the sides of the tank. The deposited copper will prevent the cathode from sliding in the groove, but when the cathode is removed, the strip 27, which slides easily, will be removed with it, andso all such difficulties are avoided.

The spraying disks 7, are preferably made of rubber or of lead, with serrations 26, and perforation 28, to facilitate the spraying of the liquid into the gas and the submergence of the gas in the liquid. The disks are held in position on the shaft by the Washers 12, and the annular rings 88, inserted between the washers, and arranged so that the whole can be made tight and rigid by the screws 39 at the ends of the shaft. If the shaft, or compression rings, are to be protected from the corrosive action of the gas and the electrolyte, it is best. done as shown in Fig. 9, by peripheral rings of 'rubber 36, inserted between the washers `12.

The cover 2, is usuallyprovided with a lead'lining 23, to protect the steel cover from the action of the liquids and gases, and also to make the cover tight. The cover is fitted tightly 'to the lower section of the electrolyzer, and held in position by means of the beams 41, and the rods 42 passing through the side walls of the tank.

It is well known that depolarization is facilitated by heating and by agitating the electrolyte. Steam may be introduced into the cell with the gas, and agitation may be effected by withdrawing a portion of the gas from the cover, or upper section, of the cellabove the electrolyte and forcing it into the lower portion of the electrolyte; this not only agitates the electrolyte, but also causes a certain amount of absorption of the gas in the electrolyte, and brings a portion of the gas directly in contact with the electrodes. This is shown somewhat in detail in Fig. 2, in which the gas is exhausted from the hood, or cover, 2, through the pipe 32 by means of the exhauster 87 and forced into the distributing pipe 36, and from there distributed to the pipes 33, and into the bottom of the electrolyzer through the per- ,forated pipes 34, where it rises through the electrolyte and agitates it. To accomplish. this effectively it is desirable that the exhauster 87 should have a slightly greater suction than that which moves the gas from cell to cell. The pipes 34 have perforations 35 through which the gas is subdivided and more-or less uniformly distributed in the electrolyte, and as it rises, it depolarizes the anodes and causes effective oxidation of the l acid, when it `rnay be returned to the oreto i dissolve more copper.

The general method of attaching vthe lead lining /tothe steel cover is shown in Fig. 11, in which 50 shows the steel shell, 23 the lead lining, 53 a bolt by means of which the lead lining is secured to the steel shell, 51 a cap over the bolt head to rotect it, and lthe lead burnedridges which makes a tight and unattackable joint between the lining and the lead cap.

In the'modified arrangement of the apparatus, as shown in Figs. 5 and 6, the spraying disks act both as electrodes and as atomizers, andthe shaft acts also as a conductor of the electric current. The rotating electrodes give a positive agitation to the electrolyte, and in some cases is to 4be preferred.

The shaft 6 is preferably made hollow (Fig.`

9), and a copper bar 45 inserted in the hollow shaft to conduct and distribute the current Without too much resistance. Electrical contact with'lthe rotating shaft is made by means of a copper disk 47, rotating in a niercury bath 46. A current with the positive connection at 24 enters the tank through the conglctoi bars 15, is distributed f to the /afnodes Ll"passesthrough the electrolyte and enters the rotating disk cathodes and sprayers 7, 5, then'p'asses to the shaft as the negative conductor, and out through the copper disk 47 and mercury bath 4(5.j

In operating the yprocess and apparatus the leach solution from the ore, and preferably having itsvariable valent `saltsfrieduced` to --their lowest valency, is introduced into the electrolyier, 1 through the pipe'9 and exhausted through the pipe 10. Sulfurf'di#y oxid gas is introduced through-the: pipe'21 and exhausted through the pipe 22 in such a way as to always maintain a slight inward suction to prevent the corrosive gases from escaping from the cell and contaminating the atmosphere. At the same time a portion of the gas over the electrolyte isl exhausted from the hood 2 and forced into the lower portion of the electrolyte to agitate,Y it, although this will not always be necessary and 1nl some cases not desirable. The spraying disks are rotated at a high speed, say from 60 to 500 R. P. M. depending on the size of the disks, so that some of the liquid is sprayed, or atomized, into the gas above itv while at the same vtime some of the gas is submerged in thev liquid.

When the current is turned on, copper is deposited on the cathodes while sulfuric acid and ferric sulfate are produced at the anode, as set forth in equations' 1 and 2.

The ferrie 'sulfate finding its way to the cathode immediatel attacks the deposited copper, and is itsel reduced to the ferrous sulfate, as set forth in equation 3. If this action were to continue indefinitely the process wouldsoon become commercially inoperative. To obviate this, and 'in order mum of re-solutiono the copper, the sulfur dioxid 1s maintained in excess in the hood above the electrolyte, and as the atomizers spray the electrolyte into the sulfur dioxid gas and submerge some of the gas in the electrolyte, the ferric salt'isI reduced 4to the ferrous condition by the sulfur dioxid while at the same time an equivalent of acid is regenerated, as set forth in equation 4. Since the rapidity of this reaction depends considerably on the temperature .of

the electrolyte, it is desirable to maintain `the electrolyte fairly warm, but economy lma. best be served by preheating it.

Il'. e

order that the e ctrolyte may be uniformly treated, both in the deposition of the copper and in the reduction by means of sulfur dioxid, the electrolyte is flowed through the cell in a sinuous course, as shown in Fig. 1. This is accomplished by e anodes touch the bottom of the cell, while at the upper portion of the cell the anodes are somewhat lower than the cathodes. In this way, the solution intro- -duced' through the pipe 9, will flow in a to get a .maximum de osition with a minii arrangin the electrodes to `act as baffles, or

-weirs.

sinuous course to the outlet 1 0, and at each change o f thesinuous flow the vliquid comes infcontact with the gas and a portion of it is sprayed into the gas, so 'that the elecagitation, especially if high current densities are used. To accomplish this, a portion of the gas is exhausted from the hood and forced into the lower -portion of the electrolyte, as already described. It is not impossible to use air for this agitation, but

the gas, itself, is preferred, for if air is used the volume of the gas is increased and the gas diluted, whereas if the gas is used no dilution or increase in volume takes place. I' y It-is very desirable to always maintain the-sulfur dioXid in excess in the cell. This eXcess should be as great as can conveniently be maintained. Fortunately this can readily be done, as sulfid ores are almost always available, and the sulfur dioxid from roastin is otherwise usually a waste product. With a hot or :a warm electrolyte the space in the electrolyzer above the liquid will lcontain much of the liquid sprayed into it, as a fine mist and steam, and thus the reactions between the gases andv liquid is rapidly effected. -v

In electrolyzing solutions by the method and apparatus here proposed, it is evident' that the usual electrical connections will not suffice. In the swirl of the gases and electrolyte the usual electrical connections with the 'electrodes would. be too complicated and would be very quickly corroded, and on account ofthe difliculties of gettin at such coni nections, the practica-bility of t e apparatus might be questioned. These diliiculties are overcome by` having two conducting bars in the bottom of the'tank; one for the positive and one for the negative conductor. The electrodes rest -on these conducting bars and their weight suffices to make the proper contact for the electric current. The edges of the cathodes are insulated from the anode bar,.and the edges of the anodes are insulated from the cathode bar. The anodes may be either lead, carbon, or magnetite, or ferro silicon, and the cathodes either lead or co per.

-conductor bar, and by means of wooden rous salt in intimate contact with the anode. In this way the E. M. F. required for electro-deposition is materially reduced. Large carbon electrodes are necessarily made of slabs, but there is difiiculty in assembling the slabs to get good electrical conductivity. I overcome this diiiiculty entirely by laying the first slab on the conductor bars with one end properly insulated from the cathode grooved pieces at the sides, lay one slab vertically on top of the other with theadjacent edges contacting, as shown in Fig. 2. In this way the electrode may be built vertically as largeas desired, while the electrical Contact; between the slabs is all that is necessary. If perfecting abutting edges are desired to give a better velectrical contact, the abutting edges may be planed to a true surface.` This will not ordinarily be necessary, for, even if the contact in the be-AA ginning is not perfect, it will soon bemade so by the electrolytic action of the current in depositing copper betweenthe gaps.

It might be thought that the covered electrolyzers would complicate the electrolysis and increase the cost 0f operation. It is more likely to simplify the operation and cheapen the cost of deposition. The idea, of course, is, to use fairly large units, and while the cost of the individual cells is greatly increased, the cost of the electrolytic installation` as a whole is materially diminished. Electrolytic dynamos with a capacity of 10,000 a-mperes at 12 volts are regularly 100 made as a standard size; if a larger current is desiredtwo of these machines may beused in multiple, thus giving 20,000 amperes vat 'l2 volts. Carbon electrodes are regularly made in slabs of 50x8x2 inches, from 105 ,30'cathodes and 31 anodes there would be a total current of the 20,000 amperes. This cell would require an approximate floor space of 6x18 feet. l Y Assuming a current efficiency, yunder the conditions, of about 96 per cent., or 2.5 lbs.

of copper from cupric solutions, per 1000 ampere-hours, there would be deposited 50 lbs. of copper per hour with 20,000 amperes, 4120 or 1200 l s., perday of 24 hours,per cell.' If the deposit on each side of the cathode is a quarter inch thick, the total weight ofV thencopper on each cathode would be approximately 1155 lbs., and for 30 cathodes 125 34,650 lbs. 'Depositing at the rate of 1200 lbs. per day, approximately 26 days would be required to make this deposit. Or in other words, the cell would not have to be disturbed or the cover lifted for a period 1230` `of from 26 days to a month, when it would electrolyte, `this is not likely to cause trou-2f' ble for a deposit approximately inch thick.

There is nodiiculty in removing the -cover fromv the cells. 'i The cells are easily4 arranged so thatA they can be disconnected, one at a time, and a traveling crane used to lift the cover and place: it on a fresh cell',

While the one from.. 'vvlich'fhe cover was taken has its copper removed. In taking thek I copper out of the cells, the individual cath-4 CodesA are lifted out nWith pincers suspended from the crane.

worn out. V o

In the operation of these cells it is unnecessary to resort to expensive absorption towers and anelaborate system of pumpin and circulation, All this may be eliminate c Manifestly if the variable valent salts `can be reduced by sulfur dioxid atl all, they can always be maintained reduced under the action of this cell, practically speaking,ese cecially at fairly high temperatures, saykf rom 120to 150 degrees F. It will not-be I necessary td pass lthe electrolytev through more than one cell, although in largeplants it is preferred to pass itl through two, and

possibly three, in series, withdifferent curs. ,rent densities. In which case the gas, as

Well as theelectrolyte, isv assed succesjsivel-y through a series of ce ls, the richer electrolyte and the richer gas being preferablyl introduced into the first cell of the series.- The current density in the succeeding cells is preferably diminished in propor-` tion'v as the electrolyte becomes impoverished incopper, and the most suitable cur-f lrent density can onlybe determined by ex-.'

periment; it will usually vary from 10 `to 5. am eres persquare foot. o

Il); 'is Well know that the E. M. F. vr'equired i copper/j eposition from solutions` containi g considerablefferrous sulfate, is

greatly' reduced onlaccount of the depolar' ization 'at the anodes. The difiiculty hitherto has been to ypractically'maintain the iron in the ferrous condition, for, depolarization is effected bythe ferrous salts being oxidized, or adduced, to theferric condition, andif the reduction to the ferroussalts is promptly made', the advantages gained by the reduced El M. F. due to'depolarization,

greatly outweighs the disadvantages due to.`

the corrosive action of vthe small 'amount of ferrie salts which unavoidably exists in the electrolyte. At fairly high temperatures If lead or thick coppery cathodes are used,A the deposited copper is easily pried ofl", and the cathode returned to the cell. The anode is not'removed until sulfur dioxid isquite active iii reducing the ferrie salts; on the other hand, the gas is not as soluble in a heated electrolyte. But',

as the object is, not so much to absorb large quantities of the gas as to maintainthe ferperfect depolarization possible-in this cell the E.A M. F. should not exceed 1.5 volts.

namo of'20,000 amperes and 12 volts Wou 'deposit 9600 lbs.ofcopper per day of 24 hours, with eight cells.

The gas, 'as wellas the electrolyte is pref-4 V erably given a 'sinuous flow through the cell, 1 by the arrangement of bailies, as shown by 30 and 31.

hese baffles not only give the gas a sinuous flow throu h the 'ce l, offer a largely increase surface for .treating the gas with the electrolyte The gas `comes intimately in contact with the film ric Salts reduced, the solubility of the gas, I `.as used in this apparatus,is.not a matter of 'much consequence. With the comparatively but also"A of liquid on the surface, and as the filmbe comes charged with the gas, the spraying of l I fresh-liquid 'into the gas Washes it down and exposes fresh liquid on the surface. l Similarly,'with the rotating-disks; if the disks, for example, have .an area of 5 s feet, and rotate at' 60 R. P'. M., there will e 1800 sq. feet of Surface exposed both to the liquid and the gas, per minute, and if there are 20 disks in a cell, the total exposure would be 36,000 sq. feet of 'fresh surface per minute'. This, in addition tothe spray, or atomized liquidyflling the hood, is believed to give the' most effective treatment possible for elect'rolytic work involving the treatment-'- of the electrolyte with the gas.

i'oo

Circulation ofv theA electrolyte may also 'l charged liquid in the upper portion of the apparatus, through. the ducts 55,' (Fig. 2) to the loyver portion of thetank It may circulate with or WithoutV the gas leading to the gas distributing pipe 34.

-The apparatus may b e used for various purposes, as for example, the treatment of ores by chlorination, the precipitation of metals from either acid orl alkaline solu- I tions, themanufacture of sulfuric acid, and

ii-o

the purification of Water. It may `be used for oxidizing as well as reducing reactions. In the'electrolysis of a substance involving, the-liberation of a gas, the excess lgas 11berated by the electrolytic action rises to the y `surface-,land maybe effectively absorbed by the spraying device in the hood. The slight -rnodications required,A if any, to adapt the v apparatus to various uses, `will readily sug-l gest themselves to any one skilled in th e art. If 5. carbon, magnetite, or ferro-silicon anodes are used, the size of the cell will be limited by the size of the anode slabs. If, however, lead anodes, and lead or copper cathodes, are used, the size of the cells may' be greatly increased. Electrodes 10250 feet X inch'thick, in a cell 18 feet long', would Seem quite reasonable for practical construction and operation. Such a cell would take 100,000 amperes, at 10 amperes per square foot, and should deposit from 5000 to 6000 pounds of copper per day of 24 hours. The cost of such cells would be rather high, but the cost of the electrolytic installation, as a whole, would be comparatively low. It would be much less than with the small 'or moderate sized cells at present used.

The end strips 27, Fig. 7, may be attached to the electrode 5 by drilling a hole through the strip and into the edge of the electrode, and then fastening the strip to the electrode by means of a lead or wooden pin 50, which C is unaffected by the electrolyte, and can be .20

replaced as desired.

I claim:

1. In electrolyticr apparatus a chamber having a gas inlet and a gas outlet and a liquid inlet and a liquid outlet and adapted to contain a liquid and to confineY a gas over the liquid, electrodes within said chamber arranged to give the electrolytic a sinuous .How from the inlet toward the outlet, means for charging the electrolytic with the gas confined over it, and means for electrolyzing the liquid.

2. In electrolytic apparatus a chamber having a gas inlet and a gas outlet and a liquid inlet and a liquid outlet and adapted to contain a liquid and to confine a gas -over the liquid, electrodes within saidchamber arranged to give the electrolyte a sinuous flow from the inlet toward the outlet, means for electrolyzing the liquid, and means at `the crests of the sinuous ow to bring the liquid in contact with the gas. .3. In electrolytic apparatus a chambe having a gas inlet and a gas outlet and a liquid inlet and a liquid outlet and adapted tov contain a liquid and to confine a gas over the liquid, electrodes within said chamber arranged to give the electrolyte a sinuous fiow from the liquid inlet toward the outlet, means for electrolyzing the liquid, and means at the crests of the sinuous flowfor spraying theliquid into the gas.

4. In electrolytic apparatus a chamber having a gas inlet and a gas outlet and a liquid inlet and a liquid outlet and adapted to contain a liquid and to confine a gas over the liquid, means Within said chamber for giving the liquid a sinuous How from the liquid inlet toward the outlet, means for electrolyzing the liquid, 4and means for intimately mixingV the gas and the liquid atthe crests of the sinuous How.

5. In electrolytic apparatus, a tank having conductor bars for the electrodes submerged in the electrolyte with removable electrodes resting thereon, means at the sides of the tank through which the conductor bars may be removed and replaced.

6. In electrolytic apparatus a tank having the conductor bars for the electrodes submerged in the electrolyte, meansl at the sides of the tank through which the conductor bars may be removed and replaced, and means arranged for making the electrical connections with the conductor bars on the extension of the bars outside of the apparatus.

7. In electrolyti'c apparatus having submerged conductor bars, electrodes composed of superimposed sections with the lower section resting on the conductor bar.

8. In electrolytic apparatus having submerged conductor bars, electrodes composed of superimposed sections with the lower section resting on the conductor bars and the remaining sections making electrical connection through abutting edges and the Contact originally due to their weight.

9. In electrolytic Aapparatus arranged to confine a gas over the electrolyte, conducting bars in the bottom of the electrolyzer and electrodes composed of superimposed sections resting on the conductor bars said sections making electrical contact from one to the other through abutting edges and the weight of the electrodes.

10. In electrolytic apparatus, a lower section adapted to contain a liquid, a removable upper section engaging the lower section and adapted to confine agas, electrical conductors submerged in theelectrolyte in the lower section, and electrodes resting on the Vsubmerged conductors and making electrical contact therewith.

1l. In electrolytic apparatus with conductor bars for distributing the electric current to the electrodes submerged in the electrolyte, conductor bars made of copper to give the necessary conductivity and -protected by a casmg capable of resisting the corrosive action of the electrolyte.

l2. In electrolytic apparatus a chamber adapted to contain a liquid' and to confine a gas over the liquid, means4 within said` chamber for charging the liquid with the gas over 1t, means for electrolyzing the liquid, and means forwithdrawing a por- `liquid,'electrical conductors submerged in theelectrolyte inthe lower section, removable stationary electrodes resting on the submerged conductors, means for passing an electric current through the conductors and the electrodes, and means for withdrawing a portion of the gas in the upper section and forcing it through the liquid in the lower section.

Y 14. In electrolytic apparatus having pipes forv distributing a gas in the electrolyte,

pipes arranged in parallel series under the electrodes with the ends. projecting through the sides of the tank, means in connection with the pipes for preventingthe escape of the liquid, a common main connecting the series of pipes, and means outside of thel apparatus for connecting and disconnecting the pipes and the main without disturbing adapted to containa liquid and to confine aing a flow of gas through the chamber oven the distributing Ypipesa'n the tank.

15. In electrolytic apparatus, a chamber gas over the liquid and having a gas inlet and a gas outlet and a liquid 'inlet and a liquidv outlet, means for causing a low of liquid through the-chamber, means for causthe electrolyte, said pipes being arranged ist in parallel series under the electrodes and parallel therewith.

17. In electrol tic apparatus, a chamber adapted to contain a liquid and to eonfinea gas over the liquid, means for withdrawing a portion of the gas from above the surface of the liquid and introducing it into the liquid below the electrodes through a permeable surface .adapted to subdivide the gas, and means for electr'olyzing the liquid with the subdivided gas ascending through it. l

18. In ele'ctiolytic apparatus having a gas inlet and a gas outlet and a liquid inlet and a liquid outlet and adapted to contain la liquid and to `confine a gas over the liquid, means forniaintaining a flow of gas from the gas inlet toward Mtlaegas outlet-with a slight 4suction (inwardly, means having4 a greater suctionfor withdrawing a portion ofthe gas from the stream and injecting it into the lower portion of the electrolyte and means for electrolyzing the liquid.

19. Iii electrolytic apparatusl l gas inlet and a gas outlet and a liquid in- Iet and a 1i uid outlet and adapted to contain a liqui and to confine a gas over the liquid, electrodes arranged to cause the electrolyte to flow from the inlet toward the outlet in a, sinuous stream, and means for injecting a gas into the lower portionof the electrolyte. I

having a 20. In electrolytic apparatus having electrical lconductors submerged in the electrolyte and electrodes resting thereon, strips at the ends of the electrodesto hold the electrodes in position and loosely arranged within the electrolyte tank so that they may `be removed with the electrodes.

21. In electrolytic apparatus, a lower section adapted to contain the electrolyte and the electrodes, an upper section engaging the lower section and forming a sealed chamber therewith, means for introducing a gasin the upper section, means for spraying the electrolyte in the lower section intoy the gas in the upper section, and baffles arranged in the upper section for giving thegas a sinuous flow through the chamber.

22. In electrolytic apparatus having submerged conductor bars of both polarities, anodes composed of superimposed sections making electrical contact through abutting edges, and arranged so that the lower section is inelectrical contact with lthe anode and' removable electrodes resting thereon,

means at the sides of the tank for maintaining the electrodes in a vertical position, and means along the edges of the electrodes for insulating the electrodes of one polarity from the electrodes of the opposite polarity.

25. In electrolytic apparatus having the edges of the electrodes protected with insulation strips, holes arranged along the edgesof the electrodes, and pins in connection with said holesior fastening the insulation strips to the edges of the electrodes.

26. In electrolyti'c apparatus having electrical conductors submerged in the electrolyte and electrodes composed of superimposed sections resting thereon, supporting strips at the sides of the electrolyte tank arranged-with grooves to receive the electrode section and maintain the electrodes in position. y

27. In electrolytic apparatus, a chamber adapted to contain a liquid and to confine iin a gas over the liquid and having a gas inlet and a gas outlet' and a liquid inlet and a liquid outlet, means for causing a flow of liquid through the chamber,'means for causing a low of gas through the chamber over the liquid, means for withdrawing a portion of the gas from above the surface of the liquid and introducing it' belov7 the surface of the liquid through a permeable surface adapted for subdividing the gas, and means for electrolyzing the liquid.

28. In electrolyti'c apparatus, anodes composed of horizontally disposed superimposed Sectional components with the lower section resting on an electrical conductor submerged in the electrolyte and making 10 electrical contact therewith and arranged so that the sectional components make electrical Contact 'With one another through their respective horizontal abutting edges.

lVILLIAM E. GREENAWALT.

lVitnes'ses MARY H. VVooLsEY, CoRA M. GREENAWALT.