US2017584A - Electrolytic cell - Google Patents

Description

Oct. 15, 1935. J H, CALBECK 2,017,584

ELECTROLYTIC CELL Filed July 11, 1931 5 Sheets-Sheet 1 Q we INVENTOR.

ATTORNEY.

0d. 15, 1935. H, CALBECK' 2,017,584-

ELECTROLYTIC CELL Filed July 11, 1951' 5 Sheets-Sheet 2 a ATTORNEY.

Oct. 15, 1935. CALBECK 2,017,584

ELECTROLYTIC CELL Filed July 11, 1931 5 Sheets-Sheet 3 r\ & Q Q x Q M Q g. N N N W s a i N is x 1 W 1n 1 A TTORNEY.

Oct. 15, 1935. H AL E K' 2,017,584

ELECTROLYTIC CELL Filed July 11, 1931 5 Sheets-Sheet 4 1 N V EN TOR.

A TTORNEY.

Oct. 15, 193 J. H. CALBECK ELEC TROLYTIC CELL Filed July 11, 1931 5 Sheets-Sheet 5 INVENTOR. Moi/7 )6. 50/660% W ATTORNEY.

Patented Oct. 15, 1935 UNITED STATES PATENT" OFFICE 16 Claims.

This invention relates to electrolytic deposition of metals, and more particularly to electrolytic cells.

The principal objects of the invention are to eifect removal of deposits from electrodes while electrolysis is proceeding and to assure high efiiciency of electrolyzing current.

Further particular objects of the invention are to facilitate removal of deposits froma lead bearing electrolyte on insoluble electrodes, and to control the character of the deposits for obtaining products having desired qualities.

Other objects of the invention will appear in the course of the description of one form of apparatus for carrying out the invention which is illustrated in the accompanying drawings, wherein: 4

Fig. 1 is an-end elevation of a set of cells embodying the invention, buss bars and electroderotating shafts being shown fragmentarily.

Fig. 2 is a plan view of the cells partly in section on the line 2-2, Fig. 1.

Fig. 3 is a longitudinal vertical section through one of the cells on the line 33, Fig. 1.

Fig. 4 is an elevation of the end of the set of cells opposite to that shown in Fig. 1.

Fig. 5 is a vertical transverse section through one of the cells on the line 5,5, Fig. 3.

Fig. 6 is a fragmentary section on the line 6-6, Fig. 5, rotative electrode rods being shown fragmentarily.

Fig. '7 is a. section through a worm and cam on Y an electrode-rotating shaft on the line 11, Fig. 4.

Referring in detail to the drawings:

l designates tanks-formed preferably of fir or pine boards, each having vertical side walls and a semi-circular concave bottom, and end walls I2 inset from the end edges of the side walls and bottom. Since the tanks are alike, only one will be described in detail.

Electrolyte is suppliedto the tank by any suitable means, for example by a pipe l3, Fig. 5, discharging into the open top of the tank, and overflows through an outlet pipe [4 adjacent the top of the tankwhereby the electrolyte may be maintained at a desired level indicated at iii in Fig. 3 during electrolysis. The outlet pipe I4 preferably includes an L having a nipple at each end and forming an inverted U, the connecting body of the U being rotatably mounted in a side wall of the tank, whereby rotative movement of the U may vary the angles of the branches or sides to the vertical and vary the elevation of the inlet end of the pipe l4. The electrolyte is then drawn from the tank in any suitable manner, for example by a pump (not shown).

Floatable in the electrolyte is a wooden drum 20 having inset end walls 22 provided with hollow axles or hubs 24 and 26 afiording communication, 5 between the drum and the tank. One or both of the hubs may move in wooden guides 28 which restrict the' drum to vertical movement in the electrolyte and retain the axis of the drum in the vertical plane of the longitudinal median line of the tank. Spaced perforate plates 30 on the drum form cylindrical electrode surfaces adapted to engage a cylindrical current conducting spool 32 having steel shaft portions 34 and '35 journaled in con 1!! ductive bearings 36 on the tank end walls. Flanges 38 on the bearings, Fig. 3, are connected by buss bars 40 with a source of electrical energy for conducting current through the bearings and shaft to the spool and drum. The spool preferably consists of an aluminum tube having brass end plugs 33 in which the shaft portions are fixed, as shown in Fig. 3, and is supported at a suitable elevation so that its surface moves beneath the surface of the electrolyte, when the level of the electrolyte is at a maximum as shown in Fig. 3. K

The drum, together with deposits on the plates, is adapted to be supported by its own buoyancy in frictional engagement with the spool, whereby rotation of the spool by a crank 42 or through a pulley 44 will efiect rotation of the floating drum. Suitable means such as a clutch, not shown, is provided for controlling the operation of the spool by the pulley.

The buoyancy of the drum is controlled bya vertical air pipe 46 in the drum, as best shown in Fig. 3, which is connected by a nipple 41 located in one of the axles with a vertical air pipe at extending in the tank outside of the drum and connected through a T 49 with a'fiexible tube 50. A two-way valve 52 in the T maybe adjusted to vent air from the drum as electrolyte enters through thehollow axles, or permit de- I livery of air from a compressor (not shown) under low pressure to displace electrolyte from the drum. I a 1,

The pipe 48 is also connected to a pressure gauge whereby the magnitude of the buoyancy of the drum may be judged. r

The drum is adapted when substantially full of liquor to sink away from the spool until the protruding axles seat on wooden supports or stops 54 fixed. to the end walls of the tank, whereby the drum will be supported above the 55 bottom of the tank. Portions of the nipple and pipe 48 may move in the wooden guide at one end of the tank for centering and supporting one end of the drum.

Air may be delivered under pressure to any desired extent for driving liquor out of the top half of the drum, and any degree of buoyancy may thus be obtained from zero up to the maximum possessed by the unloaded drum when half full of air and floating in a full tank.

A second electrode comprises a series of rods 60 which may extend in any desired direction in a tank conformably to other details of structure and to cooperate with the opposite electrode, and are movably supported as presently described. In the form of apparatus illustrated, the rods are cylindrical, and extend horizontally, parallel to the axis of the drum and are arranged in pairs on a curve concentric with the surfaces'of the curved plates. The rods are spaced from the surface of the plates when the drum floats in the electrolyte as best shown in Fig. '5. A sufiicient number of rods are installed to surround about one-half of the drum.

Opposite ends of therods of each pair are rotatively supported in recesses in opposite end walls of the tank (Fig. 6) and the other ends of the rods extend through the tank walls through end plates 62 fixed to the outer faces of said tank walls (Figs. 1 and 4'). Glands 64 are mounted in recesses of the plates for assuring electrical connection between the plates and the rods and preventing leakage from the tank. The rods and plates are preferably made of stainless steel or suitable alloy insoluble in the particular electrolyte used.

The plates are connected with a circuit by buss bars 66 which constitute one pole of the cell, the rods thus becoming electrodes.

The rods of each pair are closely adjacent each other and may touch, to efiect dislodgement of deposits therefrom when the rods are moved relatively to each other as later described.

The pairs of rods are preferably arranged. in two series below the lowermost position of the drum and overlying opposite bottom portions of the drum, as best shown in Fig. 5, so that deexample in pairs, as illustrated in the drawings.

Means acting on the rod electrodes of both tanks are provided for dislodging deposits from the rods as will now be described.

Mounted on the projecting ends of the rods exterior to the end plates are gears Ill, each meshed with a gear on the adjacent projecting end of a rod in the series, as shown in Figs. 1 and 4. The projecting ends of half of the rods of each series form a group connected by gear trains at one end of the tank, and the oppositely projecting ends of the other rods of each series form a group geared together at the other end of the tank. One rod in each group projects beyond the outer rod ends" to provide portions designated 12in Figs."1,4, and 6 to'whichlevers II and 16 maybe keyed. TI and. 18 pivoted'to the levers are pivotallyconnected to two part collars or housings 88 eccentrically movably mounted on a shaft 82 extendingbetween the tanks, as best shown in Figs. 2 and 4. Cams or eccentrics 84 within the housings and keyed to the shaft, as shown in Figs. 2 and 7, oscillate the housings to swing the levers and move the rods of each pair rotatively alternately directions.

, Ratchets 90 fixed to the end plates, engage the teeth of pawls 92 mounted on the levers for. preventing movement of one gr up of rods of each series while the levers at-t e other end of 10 the tank are acting the other group of rods.

The shaft 82 is rotated to rotate the eccentrics by a drive shaft 94v having a worm 96 meshed with a worm wheel 98 keyed to the outer end of the shaft 82 as best shpwn in Figs. 1 and 2. De- 15 posits on the drum may be removed by a shipping plate lllll as later described.

The apparatus will be further described as applied to effecting electrolytic deposition of sponge lead and lead peroxide from a lead acetate solu- 20 tion in a single cell. For such purpose the plates on the drum are formed of material insoluble in the electrolyte, such as copper, brass, Monel metal, or steel and are preferably made of aluminum. The plates tightlyengage the drum and :6 act as hoops or bands to hold the drum together, the drum being preferably made of new wood so that swelling of the wood will assure atight fit of the plate. The cylindrically formed plates are spaced longitudinally on the drum from each 30 other and from the ends of the drum by a substantial distance, for example two inches. The perforations in the plates are preferably threeeighths inch round holes through which the wooden surface of the drum is exposed.

Electrolyte delivered to the tank fills the sam to a level controlled by adjustment of the overflow U pipe, and the pipe is adjusted to effect submergence of the drum which can rise no I further than the spool. The buoyancy of the drum hold it against the spool and rotation of the spool will therefore effect rotation of the drum to move the surface of the electrode plates 30 through the electrolyte, the pressure ,of the v drum against the spool being adjusted by adjustment of the pressure of air delivered to the drum.

The plate covered drum is connected with a circuit through the buss bars'to constitute the bars the negative pole of the cell, the plates thus becoming the cathode on which sponge lead will be deposited.

The electrolyte is allowed to flow through the cellat a rate of three or four gallons per minute depending uponthecurrentrate andthelead content of the liquor. The electrolyte should be at a temperature of not less than 120 F. The drum is now made to 'rev'olve by engaging the clutch and a current density of between 20 and 40 amperes per square foot of cathode area turned p on. Sponge lead begins to form on the cathode drum at once and lead peroxide to collect on the inside surface of the anode rods.

The perforations of the covering of thedrum provide means enabling the light sponge lead deposit to cling to the drum until it can be rolled 5 into the perforations by passing under the drive spool which now acts as a roller as well as for conducting the current to the drum and as a means of rotating the drum.

After a number of revolutions the sponge lead has filled'the perforations-and has been rolled out to .forma solid sheet over the entire surface of the drum. As time goes on the drum becomes heavier becauseof the growing deposit'of lead upon it andthe pressure of air in the drum is in opposite 5 then increased in order to increase the buoyancy of the drum and maintain the drum tightly against the drive spool.

Adjustment of the pressure of the air in the drum also controls the pressure of the spool against the deposit, and provides means for obtaining either a light or a very dense deposit of sponge lead.

If the sponge lead is to be melted down into pig lead as much pressure as possible is used throughout the period of deposition. If a very light sponge is desired such as would be used in the manufacture of lead oxides, only enough pressure is used to keep the drum up against the drive spool.

After the deposit becomes more than one-half inch thick it should be removed from the drum. This may be done without shutting off the current. The clutch is released to stop the rotation of the drum. A furrow is cut in the sponge lead with a sharp tool the length of the drum and parallel to the drive spool, and through the deposit dowri to the metal covering of the drum. The edge of the steel stripping plate I may then be placed in the furrow, one side or edge of the plate resting on one side edge of the tank and preferably pivoted to the tank as shown. The clutch is again engaged and one revolution of the drum forces the deposit up against the stripper which strips off the sheet of sponge lead and disposes of it over the side of the tank.

As soon as the deposit is removed it is necessary to reduce the pressure in the drum, otherwise the new deposit will be under too great pressure and may have a tendency to break off.

If the period of deposition is long, the sponge lead will grow over the ends of the drum for two or three inches. This light deposit may be removed by hand while the stripping plate is removing the main body of the deposit from the drum, the spacing of the plates from the ends of the drum facilitating removal of the over growth.

When the current is turned on a deposit of lead peroxide begins to form on the inside surfaces of the anode rods presentedto the cathode drum, and after several hours it becomes thick enough to remove. All the rods are given a few turns at regular intervals, either by means of a crank or by the mechanical device above described. The peroxide, being quite friable, breaks off into small grains and falls to the bottom of the cell. This is allowed to remain in the cell covered by electrolyte, until the accumulation begins to touch the lower rods and then the cell must be drained and the peroxide removed through the manhole.

It is advisable to strip the sponge lead from the drum just before shutting down to remove peroxide from the rods, otherwise the sponge lead will oxidize while standing out of the liquor and may break oif when electrolysis is resumed.

Attention is caled to the fact that the drum may be and preferably is submerged throughout substantially the entire period of depositing, to prevent exposure of the sponge lead to air sufiiciently to dry the surface and bring about oxidization of the sponge lead. Should a portion of the deposits on the cathode be oxidized and converted to monoxide of lead, the monoxide would be dissolved in the electrolyte and additional current would be required to redeposit the oxidized dissolved lead.

The level of liquo in the tank is maintained high enough during operation for the liquor to just cover the drum. When the sponge lead is being 'stripped off the drum, however, the overflow pipe is adjusted to lower the level of liquor.

side of the tank with the sponge lead, as at It, 15

Fig. 5. v

The drum still engages the spool however, and

the electrolytic action continues during the relatively short time required to remove the deposit.

In using the invention, a floating electrode may cooperate with movable rod electrodes to eifect deposits on either according to the duty required of the cell, the deposits will be ,zsubmerged throughout the process of electrolysis, and deposits may be removed from electrodes without exposure of the deposits to air and while electrolf ysis proceeds. When one electrode is a floating drum, and particularly when the drum is a cathode for collecting sponge lead, the'dep'osit may be rolled on the drum and the density of the deposit may be controlled.

What I claim and desire to secure by Letters Patent is:

1. An electrolytic cell including a tank having an outlet above the bottom thereof for maintaining a level of electrolyte in the tank, a buoyant electrode in the tank floatable in the electrolyte, and an insoluble electrode having fixed position in the tank, and means for regulating buoyancy of the buoyant electrode.

2. An electrolytic cell including at nk, means for maintaining electrolyte at a predetermined level in the tank, a hollow buoyant electrode for support by the electrolyte, and means including a member affording communication .between the 3 interior of the electrode and atmosphere for controlling the buoyancy of the electrode.

3. In an electrolytic cell including a. tank for containing an electrolyte and an electrode, a movable deposit-collecting electrode buoyant in the 40 electrolyte, means engageable with'the movable electrode for moving said electrode and means for increasing the buoyancy of said movable electrode as a deposit grows to retain said electrode in driving relation with said engaging means.

4. An electrolytic cell including a tank, means for ma ntaining a relatively constant level of electrolyte in the tank, an electrode in the tank, a revoluble cylindrical electrode floatable in the electrolyte, means for supporting the revoluble electrode in the absence of electrolytefa movable current-conducting member engageable with the revoluble electrode when said electrode is-floated for coincidently conducting current to and revolving said electrode, and pneumatically operat- 5 ing means for moving the revoluble electrode and said member relatively to each other to effect engagement between said member and said electrode.

5. In an electrolytic cell including a tank, a composite electrode including a pair of parallel deposit-collecting rods located sufllc'iently close to each other to effect engagement between deposits formed thereon, and means for moving said rods relatively to each other for dislodging said deposits.

6. In an electrolytic cell including a tank and an electrode, a second electrode comprising a plurality of series of rods arranged in pairs substantially parallel with the first named electrode and in substantially equally spaced relation with a portion of the surface of said electrode, opposite ends of the rods of each pair projecting oppositely from the tank to form groups of rod ends, buss bars in conductive relation with said groups of projecting ends of saidrods, meshed gears on the ends of the rods of each group, a lever keyed to one rod in each group, eccentrically operating means for moving the levers for moving the rods rotatively alternatively, and means for restraining one group of rods while the associated group is being moved.

7. An electrolytic cell including a tank formed of non-conductive material and having-an arcuate bottom and provided with an adjustable overflow pipe adjacent the upper edge of said tank for controlling the level of electrolyte in the tank, a buoyant drum' comprising a cylindrical body formed of non-conductive material and having end walls sealingly connected to the body to retain air in the drum, .a cover on the drum comprising a plurality of spaced cylindrical perforate metal sheets having ends spaced from the ends of the body to form an electrode, hollow axles on the drum affording communication between the drum and the tank, means on the tank to engage-one of said axles for supporting the drum, a pipe in one of said axles for conducting air to and from the drum, means for restraining the drum to vertical bodily movement in the tank, conductive bearings on the tank, a metal cylinder having shaft portions journaled in said bearings and rotatably supporting the cylinder in a position to engage the drum, an electrode arranged arcuately below the drum, means forpassing current through the electrodes and electrolyte, means for rotating the cylinder to rotate the drum, and

means for removing deposits from the electrodes.

8. An electrolytic cell including a tank formed of non-conductive material and having an arcu-' ate bottom and provided with an outlet adjacent the upper edge of said tank for maintaining a constant level ,of electrolyte delivered to the tank, a buoyant drum comprising a cylindrical body having end walls sealingly connected to the body to retain air in the drum, a coveron the drum comprising aplurality of spaced cylindrical perforate'metal sheets having ends spaced from the ends of the body to form an electrode, axles on the drum including a hollow axle communicating with the tank, means on the .tank to engage one of said axles for supporting the drum, a pipe comlnunicating with the drum for conducting air thereto and therefrom, means for restraining the drum to vertical bodily movement in the tank, conductive bearings mounted on the tank, a metal tube, a shaft having portions journaled in said bearings for rotatably supporting the tube above the drum to engage the drum, electrically controde to maintain substantially uniform pressure 1 contact with 'the roller and uniform spacing thereof from the second electrode. a

10. In an electrolytic cell including a tank and anlelectrode, a second electrode in the tank -cginprising 'a' plurality of rods arranged in pairs fsubstantially parallel ngth the first named. electrode and having opposite ends of the'rods of each pair projecting oppositely from the tank, buss bars in conductive relation with the projecting ends of said rods, and means operably connected with the ends of the rods for rotatlvely 5 moving said pairs of rods to remove deposits formed on said rods.

11. An electrolytic cell including a tank having an outlet above the bottom thereof for maintaining a level of electrolyte in the tank, a hollow electrode floatable in the tank and having a port through which electrolyte flows into the interior of the tank to load said electrode for sinking the electrode to a predetermined depth, an electrode having fixed position in the tank, and means for supplying a pressure medium to the interior of the hollow electrode to displace the electrolyte when the buoyancy of' the electrode is reduced.

.trode is' reduced by accumulating weight of the deposit on said collecting surface.

13. An electrolytic cell including a tankfor containing an electrolyte, a buoyant electrode floatingly supported upon the electrolyte in the tank, a second electrode comprising a series of substantially parallel members arranged adjacent the surface portion of the buoyant electrode, and fluid means for variably loading the buoyant electrode to vary its buoyancy as a de- 40 posit grows on the surface thereof to maintain substantially uniform placement of the buoyant electrode to the second electrode.

14. An electrolytic cell including a tank for containing an electrolyte, a buoyant cylindrical electrode floatable in the electrolyte, means for suspending said electrode above the bottom of the tank in absence of electrolyte, a second electrode below the cylindrical electrode comprising a series of elongated members arranged substantially parallel with the axis of the buoyant electrode and in substantially equally spaced relation with a portion of the surface of saidelectrode, and means for controlling buoyancy of the buoyant electrode to maintain substantially uniform submergence thereof in the electrolyte.

15. An lectrolytic cell including a tank for containing electrolyte, a hollow buoyant electrode floatable in the electrolyte, a second electrode formed of material insoluble in the electrolyte, means for supporting the second electrode in fixed position within the tank, and means for controlling buoyancy of the buoyant electrode for controlling spacing from the second electrode.

16. In an electrolytic cell including a tank, a composite electrode including a pair of deposit collecting rods, means for supporting said rods in the tank sufficiently close to each. other to effect, engagement between deposits formed thereon, 70 and means'for rotating the rods in oppositedirections for removing deposits therefrom.

' JOHN H. CALBECK.

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