US1788512A

US1788512A - Electrolysis

Info

Publication number: US1788512A
Application number: US189822A
Authority: US
Inventors: Fireman Peter
Original assignee: MAGNETIC PIGMENT Co
Current assignee: MAGNETIC PIGMENT Co
Priority date: 1927-05-09
Filing date: 1927-05-09
Publication date: 1931-01-13
Anticipated expiration: 1948-01-13

Description

Jan. 13, 1931. P. FIREMAN 1,788,512

ELECTROLYSIS Filed May 9. 1927 3 Sheets-Sheet 2 DISEDIZIEIZEEDDEE EEEEEUQGEDEDE EDCIEEEEGEEEEE INVENTOR ATTORNEYS Jan. 13, 1931. P. FIREMAN 1,788,512

' ELECTRQLYSIS Filed May 9. 1927 SSheets-Sheet 5 INVENTOR BY rCQm/v ATTORNEYS Patented Jan. 13, 1931 UNITED STATES PATENT OFFICE y PETER FIREMAN, OF TRENTON, NEW JERSEY, ASSIGNOR TO MAGNETIC PIGMENT COM- PAJSIY, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK ELECTROLYSIS Application filed Ma 9, 192%. Serial no. 189,822.

This invention relates to electrolysis, and particularly to the production of alk all'es and metallic salts in a single electrolyt1c operation, the alkali and salt solutions being -re- 5 covered separately. I

In the production of metalllc salts and alkalies by electrolysis difficulty is encountered because of the interdifl'usion of-these products. Thus, if ferrous chloride and sodium 1 hydroxide, for example, are produced 1n the same cell the interdiffusion results in a precipitate of ferrous hydroxide. The accumulation of such a precipitate in the cell rapidly reduces the efliciency thereof. The cell '15 quickly becomes inoperative and must be emptied and cleaned.

In United States Letters Patent No. 1,490,- 372, issued April 15, 1924, I have described an electrolytic cell and the method of operating such a cell to produce solutions of metallic salts and of alkalies such, for example, as ferrous chloride and sodium hydroxide by electrolysis of a solution of sodium chloride in the presence of an iron anode. The cell described in the patent is divided by a separator into anode and cathode compartments. The separator permits operation for more or lessextended periods by limiting the interdifi'usion of the products in the anodic and cathodic compartments. Nevertheless interdifiusion occurs to a sufiicient extent so that operation of the cell must be stopped more or less frequently for cleaning.

It is the object of-the present invention to. avoid the difficulty experienced in the opera- .tion of cells of the character described and to permit substantially continuous operation thereof for much longer periods by preventing the interdifiusion of the anode and cathode liquors in' a more thorough manner. A further object of the invention is the provision of an improved electrolytic *cell and of a novel method of operating such a cell to permit the simultaneous production of solutions of alkalies-and of metallic salts in a substantially continuous manner.

I have discovered that interdifi'usion in electrolytic cells designed to permit the production of solutions of metallic'salts and the alkalies can be prevented by maintaining an independent body of the electrolyte between the anode and cathode compartments and by constantly renewing this body of electrolyte. This independent protecting body of electrolyte provides a meeting place for the metallic salt and alkali diflt'using from the anode and cathode. The incipient precipitate in the protecting body of electrolyte is swept out by the continuous withdrawal of this electrolyte. Ordinarily the electrolyte withdrawn from the protecting body contains a little of the metallic salt and no alkali. It is possible thus to prevent the concentration of the metallic salt in the protecting body of electrolyte from increasing beyond from 0.1 to 0.3 normal while the anode liquor is'from 2 to 3 normal.

In carrying out the invention I provide a cell having preferably. a central anode and a perforated cathodes at the sides thereof with 70 I diaphragms such as asbestos sheets disposed at the cathodes, to limit the flow of the electrolyte therethrough. I provide in addition spaced separators between the anode and cathodes. These separators may be made likewise of asbestos sheets or of asbestos and paper with a fabric such as burlap. The separators are spaced apart, for example, about five-eights of an inch so as to form an intermediate compartment between the anode and cathode compartments. Each of the individual compartments is supplied constantly with the electrolyte from sources maintained at aconstant level so as to ensure the same head of liquor in each compartment. Provision is made for the withdrawal constantly of the anode liquor and of the electrolyte from the intermediate compartments Such'provision may include outletpipes with nozzles of predetermined dimensions designed to ensure a constant flow of the desired proportion. The electrolyte which passes through the cathode diaphragms is likewise withdrawn as it is formed and constitutes the alkali solution which is one of the products of the operation. The constant flow of the electrolyte through the intermediate compartments ensures the,

. maintenance therein of protecting bodies of which may be su nated with the anode liquor. The formation of precipitates in the anode and cathode compartments is thus avoided and the operation of the cell is improved materially.

The invention as described can be utilized in various electrolytic operations wherein it is designed to produce simultaneously solutions of compounds which would react if permitted to contact with each other. The

invention is particularly useful in the production of solutions of alkalies and of metallic salts, for example, the electrolysis of sodium chloride in the presence of an iron anode to produce ferrous chloride and sodium hydroxide as described in the Letters Patent aforesaid. Other electrolytes may be used, however suchas sodium sulphate bstituted for sodium chloride. Similarly other soluble salts of the alkali metals such as sodium nitrate, sodium bromide, sodium acetate, potassium chloride,

- etc., may be electrolyzed in the cell as described to produce solutions of the alkalies and of metallic salts. Moreover, by replacing the iron anode b one of zinc, nickel or some other metal w ich forms a chloride, sulphate or other salt, soluble in water but which is itself insoluble in'that menstruum, other metallic salts can be obtained along with the alkalies. The products may be recombined in accordance with the method ofthe Letters Patent aforesaid and of other patents issued to me heretofore for the production of pigments by regulated oxidation of. freshly precipitated ferrous hydroxide.

. They may be used also for any other purpose for which they are adapted and they are par- Fig. 5 'is a detail in'section showing the construction of one of the separators.

Referring to', the drawing, 5 indicates a base constructed-of concrete, for example, or

of other material which is not affected by the anode liquor A plurality of rods 6 extend upwardly from the base'and support a frame 7 forming the top of the cell. A plurality of

frames

8, 9 and 10 are supported on the concrete base and are secured by clamps 11 thereto. I The frames are held at the top of the.

cell by screws 12 supported in bars 13 which extend lengthwise of the cell on the frame 7. Plates 14 are secured to the sides of the cell and are held by the clamps 11 and screws 12,

ably of asbestos paper are likewise supported,

adjacent to the cathode plates 15 to limit the flow of the electrolyte through the cathode plates.

' Separators 17 'are supported in spaced re lation by the frames 8 and form the intermediate compartments of the cell, the space between each of the diaphragms 16 and the adjacent separators 17 being defined in such a manner by the seperators that the electrolyte therein comprises a catholyte. These separators may be constructed ofany suitable material, but preferably may comprise an inner sheet of asbestos paper 18'with layers 19 of cellulose paper thereon and protecting layers 20' of a fabric such as burlap to give additional strength to the separators.

The anodes 21 are supported by holders22 in the anode compartment 23 and are connected by conductors 24 to a source of current of a character suitable for the practice of the electrolytic operation. The cathodes 15 are likewise connected by a conductor 25 to the source of current. In operation the several compartments of the cell are supplied with the electrolyte, for example, a saturated solution of sodium chloride from constant level containers 26 disposed at the ends of the cell. The electrolyte is delivered to these containers through pipes 27 and overflows through orifices 28 to compartments 29 whence it may be returned again to the constant level containers. The electrolyte enters the several compartments through

pipes

30, 31 and 32 provided for that purpose. The liquor in the'anode compartment which, in the case of iron anodes and a sodium'chloride electrolyte, consists of a concentrated solution of ferrous chloride, descends into a chamber 33 in the base 5 and escapes through an outlet 36 having a nozzle 37 at the end thereof, the orifice of which is of such size as to ensure the continuous flow of the desired proportion of the anode liquor from the cell. Similarly the electrolyte which enters the intermediate compartments flows therefrom constantly through an outlet 38 having a similar nozzle v39 to ensure the constant flow of the desired are maintained between the anode and cathode compartments. Fresh electrolyte is delivered'constantly to the intermediate compartments, and being substantially free from the salt produced in the anode compartment or containing only a very low concentrationof such salt, it efl'ectually prevents diffusion of that salt into the cathode compartment and avoids the separation of an appreciable precipitate therein. Diffusion of the alkali into the anode compartment is prevented similarly. Consequently, when properl operated the cell as described can be used or long periods without the necessity of dismantling it for cleaning, it being necessary only to renewthe anodes as they are dissolved and to ensure the maintenance of fresh electrolyte in the intermediate compartments. Another advantage of the-cell is its simplicity of construction and the relatively slight attention which. it requires during operation. The rate of outflow of the solutions when once determined remains fixed and a constant head of electrolyte is supplied to all of the compartments from the constant level receptacle. Consequently it is necessary only to ensure a supply of the electrolyte to the constant level compartments and the maintenance of the current supplly. The only other attention required is t e renewal of the anodes as the latter are used u While I have plication of the invention to the production of ferrous chloride and sodium hydroxide, it is to beunderstood that the invention has a broader application and that, moreover, the

by the operation.

. structure of the cell may be varied to meet particular'requirements. The important features of the invention are the maintenance of the protecting intermediate layers of the electrolyte between the anode and cathode compartments and the provision inv the cell for such layers and the renewal thereof so that increase in the concentration of the salt produced in the anode compartment may be avoided.

Various changes may be made, therefore,

i in the details of arrangement of the a parahis and in the mode of operation t ereof without departing from the invention or sacrificing any of its advantages.

1. The method of conducting electrolysis with a soluble anode, which comprises "continuously supplying fresh electrolyte to an in dependent body thereof between bodies of T an electrolyte in contact with the anode and cathode, separately supplying electrolyte to the latter bodies'and continuously withdrawing a ortion of the electrolyte from the 'indepen ent body ode orfcathode. o

2. The method of conducting electrolysis with a soluble anode, which comprises separating bodies of electrolyte incontact with the anode and cathode by an independent body I e'scribed the particular apbination, with a soluble anode of a perforated cathode atone side of the cell, a porous diaphragm closely adjacent the cathode, spaced porous separators between the anode and the porous diaphragm dividing the cell into separate anode and cathode compartments and formin an intermediate compartment and means or supplying electrolyte to and withdrawing products separately from the several compartments.

. 4. The method of simultaneously producing solutions of metal salts-and alkalies which comprises electrolyzing a solution of an alkali salt in the presence of a soluble anode and a cathode, separating the bodies of salt solution incontact with the anode and cathode by an independent body which is constantly renewed without contacting the anode or cathode, and separately supplying'salt solution to the bodies thereof in contact with the anode and cathode.

In-testimony whereof I aflix my signature.

' PETER FIREMAN.

without contact with the anof electrolyte, withdrawing a portion thereof continuously without contact with the anode or cathode and replenishing the independent