US1314742A

US1314742A - Electrolytic process

Info

Publication number: US1314742A
Authority: US
Publication date: 1919-09-02
Anticipated expiration: 1936-09-02

Description

W. E. GREENAWALT.

ELECTROLYTIC PROCESS.

APP LIQATION FILED JAN. l9. I914. RENEWED DEC. 26.1918.

1,314,742. Patented Sept. 2, 1919.

2 SHEETS-SHEET l- 1s l o 7 41 10+ \l I 2 2 g 18 2 i 20 9 9 5 a 5 i 1 317 42 i i 9' 1 2 i 4 n 1 V RC2 VVz'Zzzesses Invenfor W. E. GREENAWALT.

ELECTROLYTIC PROCESS.

APPLICATION men 1AN.19.1914. RENEWED DEC-26,1918. 1,314,742.

Patented Sept. 2, 1919.

2 SHEETSSHEET 2.

T/Vz'fflesses In ven Zor UNITED STATES PATENT OFFICE.

WILLIAM E. GBEENAWALT, OF DENVER, COLORADO.

ELECTROLYTIC rnocnss.

Specification of Letters Patent.

Patented Sept. 2, 1919.

Application filed January 19, 1914, Serial No. 812,951. Renewed December 26, 1918. Serial No. 268,415.

To all whom it may concern:

Be it known that I, WILLIAM E. GREENA- WALT, a citizen of the United States, residing in the city and county of Denver and the State of Colorado, have invented cerin leaching copper ores, there is always resent iron sulfate, which injuriously a ects the operation. Ferrous sulfate is not particularly harmful in the electrolyte, but the ferric sulfate is highly detrimental. I

If a solution of copper sulfate, containing ferrous sulfate, is electrolyzed, copper is deposited at the cathode while sulfuric acid and ferric sulfate are produced atthe anode, as represented by the following. equations:

The ferric sulfate, finding its way back to the cathode, combines with the deposited copper and is again reduced to the ferrous condition, thus representing a loss of efficiency, as represented by equation:

If, however, the ferric sulfate can be reduced at the expense of a cheap reducing agent, such as sulfur dioxid, then acid is regenerated and the iron in the electrolyte loses its ability to combine with the deposited copper, as shown by equation:

sothat for every' molecule of iron that is reduced from the ferric to the ferrous condition two molecules of acid are regenerated. This acid is beneficial in the electrolyte, and on leaving the electrolyzer is further avail able for the extraction of copper from the ore.-

Similarly, if there is an excess of sulfur dioxid in the electrolyte, it acts as a depolarizer and acid generator, thus:

The effectiveness of these reactions and the practical results obtained, depends upon the thoroughness with which the sulfur dioxid is brought in contact with the electrolyte. In my process this is effectively and continuously accomplished, as will now be explained by referring to the accompanymg drawings, in which Figure 1 represents a plan through the apparatus illustrating the process;

Fig. 2, the corresponding longitudinal section;

gig. 3, the plan of a modified apparatus, an

Fig. 4, the corresponding section.

In the figures, 1 is a tank containing the electrolyte, which may be presumed to be copper sulfate solution as obtained, say, from leaching copper ores. 2 are the anodes, and 3 the cathodes, 4 is a frame hav ing stirring bars 5 interposed between the electrodes, preferably oscillating as a whole, and suspended from fixed pivotal points 6, and actuated by the mechanism 7.

10 represents the mechanism, taken as a whole, by means of which reducing gases, such as sulfurdioxid, are brought to a mi nute state of subdivision, or atomized, in contact with theele'ctrolyte, and consists, preferably, of an outer tank 9, into which the electrolyte flows from the cell through the pipe 8. Inserted within the tank 9, is a tube 11, havin perforated disks 12, and is suspended within the tank by the-shaft 13-from the ball bearings 14. This tube is made to revolve at a high speed, being driven by the pulley 15, and the motor 16. The reducing gas, say, sulfur dioxid, is produced in the generator 17 and by means of the air or gas pump 18, is forced through the pipe 19, and into the tube 11, of the atomizer, 10. 20 is the return pipe for the reduced solution, and 21 the exhauster for the excess gas, and air or nitrogen, through the pipe 22, toprevent it from getting into the cell room and contaminating the atmosphone. Or the excess gas may be forced through another apparatus in connection with another cell. i

To operate the process, the electrolyte may be presumed to be charged into the cell depolarizer. If the action at the anode were allowed to continue the reducing agent would soon be exhausted and the iron oxidized to the ferric condition, which would be highly injurious and greatly reduce the current efliciency. To avoid this a portion of the electrolyte is allowed to flow into the atomizer 10 while at the same time the reducing gas from the generator 17, is forced into the tube 11, which is revolved at a high speed, so that the gas ascending through. the

tube 11, and perforated disks is divided into minute particles, or atomized, in contact With the solution, and thoroughly incorporated with it, thus making it possible to quickly, eflectively, and continuously reduce the solution, and if desired, charge it with an excess of the gas. It is then again returned, preferably though not necessarily,

in a continuous stream to the electrodes. In this way the injurious ferric compounds are kept at a minimum or entirely avoided. The gas ascending through the tube 11, acts as an air lift, thus making it possible to return the reduced electrolyte at a higher level than the level of the electrolyte at the electrodes. The circulation may thus be accomplished by gravity and by the buoyant action of the atomized gas in the liquid.

Reducing gases, such as sulfur dioxid, are only slightly soluble in water, but by the arrangement of the present process this difficulty is overcome since the gas may be continuously applied to the electrolyte and the accumulation of the injurious ferric compounds, in injurious amounts, prevented.

As a modified arrangement, shown in Figs. 3 and 4, the atomizer might be inserted in the electrolyte tank 1, in a space reserved in the cell for the purpose. In either case a portion of the electrolyte is temporarily segregated from the electrodes and from the main body of the electrolyte and treated with the reducing gases and then again returned to the electrodes. I

The process permits of considerable gen eration of acid and the retaining of the acid in the electrolyzer to a much greater extent than is ordinarilv possible. This is a highly desirable feature, as the increased acidity, and to a certain extent the accompanying increased temperature also, greatly reduces the electromotive force required for the deposition of the copper. The excess regeneration of acid is also desirable as a solvent of copper from the ore, since more acid can be then wasted without detriment and the elec trolyte kept in a higher state of purity, and consequently of efliciency.

The process presents marked advantages fectively in contact. with the electrodes as rapidly as it is reduced, and this action is made more effective by the circulation of the electrolyte. In Fig. 4 the circulation is made more effective by introducing the gas into one end of the pipe 30, thus acting as an injector, and taking the electrolyte from the further end of the cell, while the reduced electrolyte flows in the opposite direction.

The effective depolarization brought about by this process by the use of sulfur dioxid and ferrous sulfate produces large quantities of acid, reduces the E. M. F. for the deposition of the copper, and greatly prolongs the life of the insoluble anodes. The

life of the anodes depends largely on the effectiveness of the depolarization.

I claim:

1. An electrolytic process which consists in electrolyzing copper solutions containing ferrous salts to deposit the copper at the cathode with a simultaneous oxidation of the ferrous salts to the ferric salts at the anode, agitating the electrolyte, segregating a portion of the electrolyte from the elec-' trodes, applying to the segregated electrolyte a gas capable of reducing the ferric salts to the ferrous condition so as to rise through the electrolyte by its own buoyancy in the liquid, atomizing the gas in contact with the electrolyte as it ascends through the liquid, and returning the reduced electrolyte to the electrodes. i

2. An electrolytic process which consists in electrolyzing copper solutions containing ferrous salts to deposit copper at the cathode with a simultaneous oxidation of the ferrous salts to the ferric salts at the anode, segregating a portion of the electrolyte from the electrodes, applying to the segregated electrolyte a gas capable of reducing the ferric salts to the ferrous condition so as to rise through the electrolyte by its own buoyancy in the liquid, atomizing the gas in contact.

with the electrolyte as it ascends through the liquid, and returning the reduced electrolyte to the electrodes.

3. An electrolytic'pro'cess which consists in electrolyzing copper solutions containing ferrous salts to deposite copper at the oathode with a simultaneous oxidation of the ferrous salts to the ferric salts at the anode, withdrawing a portion of the electrolyte containin ferric salts from the electrolyzer and intr ucing it into a reducing chamber, applying a gaseous reducing agent to the segregated portion of the electrolyte to rise through the liquid by its own buoyancy in the liquid, atomizing the gas in contact with the segregated electrolyte as it ascends through the liquid whereby the ferric salts is again reduced to the ferrous condition, and circulating the electrolyte between the electrolyzer and the reducing chamber by the buoyant action of the atomized gas in the electrolyte in the reducing chamber.

7 4:. An electrolytic process which consists in electrolyzing copper solutionscontaining ferrous salts to deposit the copper at the cathode with the simultaneous oxidation of the ferrous salts to the ferric salts at the anode, segregating a portion of the electrolyterfrom the electrodes, applying sulfur dioxid to the segregated electrolyte to reduce the ferric salts to the ferrous condition and' in such a way as to rise through the electrolyte by its own buoyancy in the liquidyatomizing the gas in contact with the electrolyte as it'ascends throu h the liquid, and re-- turning the reduced "e ectrolyte containing an excess of the gas to the electrodes.

5. An electrolytic process which consists in electrolyzing copper solutions containing ferrous salts to deposit the copper at the cathode with the simultaneous oxidation of the ferrous salts to the ferric salts at the v anode, applying a reducin gas to a 001 of the electrolyte in a re ucing cham ber, maintainin a flow of gas in the reducing chamber, su dividing the as in the electrolyte in the reducing cham er, and exhausting the excess gas from the reducing cham- A ber of one electrolyzer and appl ing it to the electrolyte in the reducing c amber of another electrolyzer. 4 r

6. An electrolytic process which consists in electrolyzing copper solutions containing ferrous salts to deposit the copper at the cathode with the simultaneous oxidation of the ferrous salts to the ferric salts at the anode, segregating a portion of the electrolyte from the electrodes into a reducing chamber, applying a reducing gas to the electrolyte in the reducing chamber to reduce the ferric salts to the ferrous salts, subdividing the gas in the reducing chamber, and applying a stream of gas to a stream of lyte from t e electrodes into a reducing chamber, ap lying a reducing gas to the segregated e ectrolyte so that it will rise through the electrolyte by the pressure of the liquid on the gas, thus causing a higher liquid level in the reducing chamber than in theelectrolyte tank, subdividing the as in its ascent through the segregating e ectrolyte in the reducing chamber, and maintaining a continuous flow of reduced electrolyte from the reducing chamber to the electrodes and of oxidized electrolyte from the electrodes to the reducing chamber.

8. An electrolytic process which consists in electrolyzing copper solutions containing salts'of iron to deposit the copper at the cathode with the simultaneous oxidation of the ferrous salts to the ferric salts at the anode, maintaining a continuous fiow of electrolyte from the electrolyzerto a reducing chamber, applying a reducing gas to the the electrolyte by the pressure of the liquid 7 on the gas, subdividing the gas in its ascent through the electrolyte, and maintaining the flow of electrolyte by the difference in the liquid level induced by the application of the gas in the reducing chamber.

9. An electrolytic process which consists in electrolyzing copper solutions containing salts of iron to deposit the copper at the cathode with the simultaneous oxidation of theferrous salts to the ferric salts at the anode, applying a reducing gas to a pool of the electrolyte in a reducing chamber, treating the electrolyte with the gas by intimately mixing the gas with the electrolyte in the pool, maintaining a flow of gas through the reducing chamber, and maintaining a flow of reduced electrolyte from the pool in the reducing chamber to the electrodes and of oxidized electrolyte from the electrodes to the pool.

WILLIAM E. GREENAWALT.

Witnesses:

THOMAS S. WALTEMEYER, EDWIN J. Omssunn.