US959730A - Process of treating electrolytic and similar solutions. - Google Patents

Description

G; A. GABRIEL.

PROCESS OF TREATING ELECTROLYTIC AND SIMILAR SOLUTIONS I APPLIGATION FILED MAY 31, 1907. I 959,730. Patented May 31,1910.

2 SHEETS-SHEET 1.

[WWW "Hi e. A. GABRIEL. PROUESS OI: TREATING ELEGTROLYTIG AND SIMILAR SOLUTIONS.

APPLIOATION FILED MAY 81, 1907'.

959,730; Patented MayBl, 1910i 2 sums-81mm 2-.

ii 19' o WW9; 'gnoewto Ia.

. George/{Gabriel sums STATES PATENT curios.

snoaen A; GABRIEL, or NEW YORK, it. Y., assienon' ro! BLEACH -& GAUSTIC rnoonss COMPANY, OF NEW, YORK, N. Y., A

CORPORATION or NEW YORK.

PROCESS OF TREATING ELECTROLYTIC AND SIMILARSOLUTIONS.

Specification of Letters Patent. I

Patented May 231, ram.

a ucauon'ruea May 31, mp7. .sernuno; 376,647.

To all whom it may concern: l Be it known that I, GEORGE A. GABRIEL,

a citizen of the United States, and a resi-' dent of the borough of Brooklyn, inthe city and State of New 'York, have invented certain new andsuseful-lmprovements in Processes of TreatingElectrolytic and Similar Solutions, of whichthe following is a full, clear, and complete disclosure.

This inventlon relates to processes .or

,methods of forming or purifying solutions of diiferent' saltsused in large quantities in liquid discharged from the cathode chamber,

the chemical arts, and is particularly ap-' plicable to the purification and production of solutions used in'gelectrolytic cells, such as of thel-largreares or vertical type, having the anode and "cathode chambers sep-' arated by adiaphragm for producing chlorin and caustic soda by the electrolysis of brine. In electrolytic ,cells of this type,'the electrolyte passes through the diaphragm owing to the action of the electric current and the hydrostatic pressure of'thesanolyte and is-acted upon at the cathode. 'However, more anolyte passesthrough the diaphragm than is decomposed at the cathode andthe therefore,- ontains some of the, active 'or undeoomposed electrolyte, which, if Enot collected and separated sirom the "products of decom osition, would-be wasted. 7 ne ,of

the ob ects of my invention," therefore, is to separate -the active electrolyte discharged from the cathode chamberfrom the products,

of decomposition, so that the same may be returned to the anode-chamber of the cellin 'the form of pure electrolyte.

One feature of my mvention'h-as for its object the establishing'ofcomplete cycles or circuits through whwh the solutions used l may'be' continuously passed so that the impureor" partly spent'solution may be succes- (sively treated ,-in;series of steps to purify or strengthen the same. and then immediately .be returned to the apparatus in which it used, while at thesame time the'bywproducts are-reduced to commercial substances in the form of solids or solutions.

- ,tioned that are" ofhighefiiciency, both as to IA further object of. my invention is to provide processes of the nature above menmaterials employed and the energy consumed, and also that lessen the; time and labor which has heretofore beennecesmry in producing similar results.

t'rolyte,

These and other objects and features of my invention will be hereinafter more fully set forth andiclaimed in'the accompanying 1 claims.

"solving the same in'the presence of heat and at the same time converting the remaining 1 products of decomposition into compounds,

such as carbonates which may precipitate the impurities of the raw or new elec after which the impurities may be filtered out and the electrolyte returned to the electrolytic cell or other ap The concentration is preferably accomplished by the use of suitable evaporators and by centrifugal separators or driers, the liquid thrown off by the latter either being subsequently changed to a solid fo'rm or allowed to remain as a liquid, thereby constituting two diiferent forms of finished by-product.

with an acid which reacts upon'the remaining small amounts of the products of decom- 'paratus or process. for further decompo- 'sition or treatment.

Afiter the electrolyte has been filtered to remove the precipitate, and before returning to the electrolytic cell or other apparatus, it is preferably treated position which have been converted into carbonates, such as sodium carbonate, and neutralizes the latter, forming solutions of salts which are not injurious to the further use of the brine, I v

p .In the use, bl? electrolytic cells-ibis desirable that the electrhlyte may be continuously supplied tothe cellandalso that'the else-- trolyte may I the operation of the cell, thereby obviating the necessity of interrupting the ,electrolytic process for the purpose oi-replenishing or cleansing the fluid. When the process above outlined is'fused for the-purpose of utilizing the discharge from the cathode chamber for purifying-and producing the liquid supplied to the anode chamber of an electrolytic cell, I'm'ay' combine the same with a rocess which is carried-out'in the circulating system with the anode" chamber of'the electrolytic cell. The action of the anolyte of the elegtrolytic cell upon the-anode-aml ether parts be continuously purified during ieb with which itcomcs in contact causes the anolyte to take up certain impurities in the form of solids and gases which, if allowed to remain in the anolyte, impair its action. Briefly, this process of renewing and purifying the anolyte comprises withdrawing the anolyte from the cell, passing the same through suitable bodies of the salt used in solution in the anode chamber, filtering, freeing from entrained gases or air, mixing with additional quantities of the fresh anolyte and that decomposed, while the auxiliary cycle or circulation is of alarger volume and continuously, and rapidly purifies and strengthens the electrolyte in the anode equal, at least, to the amount of the anolyte that has passed through the diaphragm or of the cell. The second process orseries of steps constitutes a cycle for the purification and strengthening of the anolyte and is a continuous circulation of the liquid. From the-point at which the active purified electrolyte resulting from the first or main cycle or circulation is added to the second or auxiliary cycle or circulation, until the electrolyte enters the anode chamber of the cell,

the two. cycles are preferably coincidentJ 'The main cycle of the process supplies the cellwithan amount of-the electrolyte equal to that discharged into the cathode chamber chamber.

For descriptions of different embodiments of my lnvention which'I deem preferable,

reference may be had to the following specification and to the accompanying drawings forming a part thereof,-in which- Figure l is a diagram of essential steps of one formof my invention and also indicating the apparatus employed therewith, and -Flg. 2 is a slmilar diagram showing additional features of the process.

Referring to Fig. 1 the numeral 1 indicates an electrolytic cell ofthe Hargreaves or vertical' type fromwhich'the eflluentor partly I decomposed electrolyte from the cathode chamber is discharged. In the case of the electrolysis of I brine this eflluent contains caustic soda and unused sodium chlorid' :The efliuentemerges from. the fcell 1 by the pipe 16 and is first passed through suitable vooncentrating apparatus, such as the 'evaporator 2 and the centrifugal separator or drier 3, which reduce the solution to the form of the salt of sodium chlorid, moistened with a slight amount of water, and traces of caustic soda. Thesalt is then dissolved in water with the addition of steam, for heating, and a suitable re agent, such as carbon dioxid, is also added. The carbon dioxid acts upon the remaining caustic soda or similar alkali and produces sodium carbonate or other carbonates. This step is preferably carried out in an agitator as indicated at a, which thoroughly mixes the ingredients referred to with the solution of sodium chlorid. When the liquid containing the sodium carbonate in solution,'together with the solution of sodium chlorid leaves the agitator, it has a specific gravity of about 2559B. It is stored in a suitable reservoir 5, where it is allowed to cool, and there becomes supersaturated. The sodium carbonate is then decomposed and produces an insoluble salts which are precipitated. This precipitation is preferably "accomplished by adding to the solution suitable quantities of fresh'brine from a source of Supply such as the reservoir 6, and which usually contain impurities in the form of salts of calcium, magnesium, etc. salts act upon the sodium carbonate or similar substances produced by the conversion 'of the alkali, and form insoluble salts,-"such as calcium carbonate, which are precipitated; The mixing of the brine with the solu tion being treated andfthe precipitation of These the impurities are preferably carried on in q a mixer indicated at 7. The mlxture is then passed through a filter,as indicated at '8, to free the same from the precipitated matter. After passing through the filter a small quantity of acid may be added to the mixture, and this is forthe purpose of neutralizing any excess alkali carbonate, there by converting the same into salts that are not'injurious to use in the electrolytic cell or other apparatus. The purified mixture or solution is then added to the circulating cycle or system connected with the anode chambers of the electrolytic cell or cells.

This preferably comprises, first, heating the electrolyte to a temperature approximatw ing that of the anolyte, and is accomplished bypassing the electrolyte through a coil placedin a tank of hot water or otherwise externally heated, as indicated at 9. After passing into the anode chamber and being acted upon by the electric current, the electrolyte is then. withdrawn throughthe ipe l6 and passed through a plurality of filters such as indicated atxlO and 11, which filters contain a quantity or layer of salt crystals whereby any weakening of the electrolyte may be compensated for. "The filter 11 is referably. provided with an outletpipe 26 'or the escape and'collection of gas Jen orator ".5.

trained in the electrolyte. -These filters remove any particles of foreign or solid mat- "ter and dirt which may be the result of theaction of the electrolyte upon the anode, firother parts of the electrolytic cell. electrolyte isthen conducted to,- and mixed with, the incom-i-nggbrine or electrolyte, the

circulation being aided suitable means," such as an air lift, as indicated at 12. All

tion 15 extending toward the bottom of.

the receptacle, and beneath which the liquid must .pass. The first-compartment formed by; the partition 15 is provided with an air outlet 25 throughwhich the air introduced by the air lift may bedischarged. In pass- .ing into the second compartment of the receptaclc 14. any gas'contained in the electrolyte is allowed topa'ss off through a connection with the pipe 26, and as the new or purified electrolyte mixed with the brine is also conducted to this compartment, they both become mixed and then, continue on through the circulating systems.

The above'is one of the simplest embodiments of my invention, but certain changes "or additions may be made therein, as indi' cated in Fig. 2. In this embodiment of the invention, the automatic centrifugal separator 17 is preferably provlded with two liquid discharge sections, from the lower one of which strong caustic soda wlthisome unused sodium ClllOIld' 1s discharged.

This is then carried to, a boat pan 18,

from which it is fed into suitable evaporating kettles 19. The product of these kettles ihcn forms one of the finished by-products, such as caustic soda in solid form.

\Vatcr is added to the upper section of the cei'itrifugal separator 17, for washing the concentrated salts therein, and this watcr, containing some salt in sohition and a slight amount of alkaline matter, such as the caustic soda, is carried to a storage tank 20, into which the elii-uent of the cell preferably discharges before passing to the'evap- This washing solution is thereby returned to the main circuit of the process and then passes through the evaporator and the concentrator and is subjected to the steps of the process just described. I also prefer to employ a second auton'iatic centritugal separator 21. This also has upper and lower liquid discharge sections, the upper onemi which'is supplied with water for washing the crystals or solid matter being treated thereby. This washing water as discharged contains a slight amount of cans tic soda, together with a slight amount of soda, and inorder to convert this into a subsodi'umchlorid that has been dissolved from. the crystals; in the separator, and .is then i also added to the storage tank-20 and sub.- jected to-the concentrating steps of the proc- The discharge from the"lowe r sectionof the separator'21. is conductedto a stor-' 'a'getank 22 and since said discharge con"- sists of practically pure "caustic soda, the

contents of the storage tank constitute-one form of commercial liquid by-product.

I The crystals or solid matter discharged by the centrifugals .17 and-21, are carried to the agitator 4; and heated in a suitable manner such as by the introduction of steam, said steam also of course providing water which 89 dissolves the solid matte-r supplied to the The crystals added to thisagiagitator.

of caustic ta'tor also contain a small amountstance which may be precipitated, I add a suitable reagent, such as carbon 'd-ioxid, which acts upon the caustic soda producing sodic carbonate. The mixture thereby obtained, in this instance the solution-of salt which is heated to a high temperature and therefore becomes supersaturated, together with the sodic carbonate in solution, is conducted to a storage tank 5, in which the solution is allowed to cool. The remainder of the process is the same as before described in connection with Fig. 1; that isto say, thesodic carbonate precipitates the impurities of the new brine, in the mixer '7. The mixture is then filtered and a slight amount of acid added to neutralize whatever slight excess of sodicrarbonatemay remain in the mixture. The mixture orsol'ution .1 is then supplied to the circulating system connected with the anode chambers of-the velectrolytic cells as before described. .5

In using the term brine 1i wishto be understood as referring to a solution of any salt'that is used as. the principal substance to be treated in the process in conjunction withan electrolytic cell or otherapparatus or process.

I wish it to be understood that I do not consider the invention to be limited totheI exact details of arrangement, materials and procedure shown and described, for-the invention is applicable to the purification of solutions used in other apparatus and processes and to solutions used in-other'ty-pesof electrolytic cells.

Various modifications are also possible invention, what I claim and desire to protect by Letters iatent is:

1. In an electrolytic process, in combination with the step of electrolysis, a continuous cycle of steps constituting a circulation-30f the electrolyte, for supplying pure I30 electrolyte equal to that decomposed or dis charged and a cycle of steps constituting an auxiliary circulation for purifying and strengthening the electrolyte, treating in said cycle a greater volume than in the main cycle.

'2. In an electrolytic process, in combination with the step of electrolysis, a continuous cycle of steps constituting a circulation of the electrolyte 'and comprising, concentrating the same to solid form, dissolving, and introducingamounts of raw electrolyte, and a cycle of steps constituting an auxiliary circulation of such electrolyte in the form of an aqueous solution, and including the steps of purifying and strengthening the same.

3. In anelectrolytic process, in combination with the step of electrolysis, a continuous cycle of steps constituting a circulation of the electrolyte and comprising concentrating the same to solid form, dissolving and introducing amounts of new electrolyte,

and a cycle of steps constituting an auxiliary circulation of the electrolyte in the form of an aqueous solution andcomprising thestep of addingv quantities of the pure electrolyte.

4. In an electrolytic process, in combination with the step ofelectrolysis, a continuous cyclev of steps constituting a circulation of the electrolyte and comprising, concentrating and separating said electrolyte from the products of decomposition so that the same may be againsubmitted to electrolysis,

and a cycle. of steps constituting an auxiliary circulation of the anolyte for purifying. and strengthening the. same.

5. In an electrolytic process, in combination with the step of electrolysis, a continuous cycle of steps'constituting a circulation and treatment of the electrolyte for eliminating the products'of decomposition. and supplying pure electrolyte, and a cycle of steps constituting all-auxiliary circulation for purifying and strengthening the electrolyte, said cycles including the step of heating to the temperature of the electrolyte maintained during electrolysis.

GQIn an electrolytic process, in combination with the step of electrolysis, a continuous cycle of steps constituting a circulation and treatment-of the electrolyte for eliminating the products of. decomposition and supplying pure electrolyte, and a cycle of steps constituting an auxiliary circulation for purifying and strengthening the elec: trolyte, the last step of said cycles being the heating of the electrolyte to its temperature during electrolysis;

7. In an electrolytic process, in combination with the step of electrolysis, a continuous cycle of steps constituting a circulation and treatment of the electrolyte for supplying pure electrolyte, anda cycle of steps constituting an auxiliary circulation, comprising, the step of removing solid impurities, the step 'of removing entrained gases,

and the step of supplying additional quantities of pure electrolyte.

8. In an electrolytic process, in combination with the step of electrolysis, the process of treating the discharged electrolyte remaining in the catholyte, which comprises tion with the step ofelectrolysis, the process 7 of treating the discharged electrolyte remaining in the catholyte, which comprises removing the undecomposed electrolyte associated with a predetermined amount of the product of decomposition, converting the said product of decomposition int-osubstances which purify the raw electrolyte, I

adding definite amounts of the raw electrolyte, and then submitting the purified electrolyte to said step of electrolysis.

10. In an electrolytic.process,'in'combina tion with the step ofelectrolysis, the process of treating'the discharged catholyte contain- .ing the undecomposed electrolyte, which comprises, separating out said electrolyte associated with a predetermined amount of the product of -decomposition, converting said product into a purifier for the raw electrolyte, adding quantities of said raw electrolyte, and then submitting the liquid obtained to said step of electrolysis.

11. In an electrolytic process, in combination with the st( p ofelectrolysis,"the process of treating the discharged product containing the original undecomposed electrolyte,

which comprises separating out said elec' trolyte associated with :a' predetermined amount of the product of decomposition, converting said product into a substance which will precipitate the impurities of the raw electrolyte, adding quantities of said raw electrolyte, removing the precipitate,

and then submitting the liquid obtained tosaid step of electrolysis.

12. In an electrolytic process,in combination with the step of electrolysis, the process of treating the discharged product containing the originalundecomp sed electrolyte, which comprises, concentrating to solid form and separating out the said electrolyte associated with a small amount of-the product of decomposition, washing the same with water, reconcentrating' said wash water, treating said concentrated electrolyte and associated product to form a purifier for the raw electrolyte, adding quantities of the raw electrolyte, and then submitting to said step of electrolysis.

13. In an electrolytic process, in combination with the step of electrolysis, the process of treating the discharged product containiiig the original undeco-mposed electrolyte,

concentrating the said electrolyte to solid form, mechanically separating said concentrated electrolyte associated With a small amount of the product of dewhich comprises,

' composition, washing the same, dissolving,

ciated with a small amount of the productconcentrating said electroout said electrolyte assoof decomposition, said concentration and separation being eiiected in a plurality of similar successive steps and producing the electrolyte as a solid after each step, dissolving the same, and then submitting to said step of electrolysis.

15. In an electrolytic process in combination with the step of electrolysis, the process of treating the dischargedproductcontaining the original undeoomposed electrolyte,

which comprises, separating out said electrolyte associated with a small amount of the latter into a substance which product of decomposition, converting the may be used for precipitating, and then addmg a solution I containing matter-to be precipitated.

16. In an electrolytic process in combination with the stepof electrolysis, the process of treating the discharged product containing' the original undecomposed electrolyte, which comprises, separating-out said electrolyte associated with a small amount of the product of decomposition, precipitating thereby the impurities in the raw electrolyte,

neutralizing any excess of the converted product of decomposition, and then submitting to said step of electrolysis.

17. In an electrolytic process, in combination with the step of electrolysis the process of treating the discharged product containing the original undecomposed electrolyte, which comprises, separating out said electrolyte associated witha small amount of the product of decomposition, precipitating, by'a suitable mixture thereof with reagents, the impurities in the raw electrolyte, adding a suitable acid to neutralize any excess of said reagents, and then submitting to said step of electrolysis.

18. In an'electrolytic process, tion with the step of electrolysis the process of treating the discharged product containing the original undecomposed' electrolyte,

which comprises, separating out said elec-' trolyte associated with a predetermined amount of the product of decomposition, treating the same with a gaseous reagent,

adding a supply of the raw electrolyte,-re-

undecomposed electrolyte,

in combinamoving the separated impurities thereby ob tained. and then submitting the purified electrolyte to said step of electrolysis.

19, In an electrolytic process in combination with the step of electrolysis, the process of treating the discharged product containing the original undecomposed electrolyte, which comprises, separating out said electrolyte associated with a predetermined amount of the product of decomposition, heating to a predetermined temperature, treating with a gaseous reagent, adding a supply of the raw electrolyte, removing the separated impurities thereby obtained, and then submitting the purified electrolyte to said step of electrolysis.

20. In an electrolytic process in combination with the step of electrolysis, the process of treating the discharged product containing the original undecomposed electrolyte, which comprises, separating out said electrolyte associated with a predetermined amount of the product of decomposition, treating with carbon dioxid, adding a sup ply of the raw electrolyte, removing the separated impurities thereby then submitting the purified electrolyte to said step of electrolysis.

21. The process of purifying an electrolyte discharged from a-cathode chamber, which comprises, separating out the undecomposed electrolyte associated with a predetermined amount of the product of decomposition, converting said associated product of decomposition into a purifier for the raw electrolyte, and adding a supply of said raw electrolyte. V

22. The process of purifying an electrolyte,which comprises, separating the undecomposed electrolyte'associated with a pre determined amount of the product of decomposition, converting said associated product of decomposition. into substances which will precipitate the impurities of the raw electrolyte, adding raw electrolyte, and removing the precipitate by filtration.

23. The process of purifying an electrolyte which comprises, separating undecomposed electrolyte associated with a predetermined amount of the product of decomposition, converting said'associated product of decomposition into substances which will precipitate the impurities of the raw electrolyte, adding raw electrolyte, removing the precipitate, and then neutralizing any excess of the converted product of decomposition. I

24. In-an electrolytic process, in. combination with a continuous main circulation of chamber, for purifying and supplying the electrolyte, a local or auxiliary circulation of the anolyte, including the steps of electrolys'is and filtering.

25. In an electrolyticprocess, in combinaobtained, and

the electrolyte discharged from a cathode tion with a continuous main circulation of the electrolyte discharged from a cathode chamber, for purifying and, supplying the electrolyte, a local or auxiliary circulation of anolyte, including the steps of electrolysis, filtering, and extracting the entrained gases.

26. In an electrolytic process, in combination with a continuous main circulation of the electrolyte discharged from a cathode chamber, for purifying and supplying the electrolyte, a. local or auxiliary circulation of the'anolyte, including thejsteps-of-electrolysis, passing through crystals of the anolyte, and filtering;

27. In an electrolytic process, in combination with a continuous main circulation of h the electrolyte discharged from" a cathode chamber, for purifying and supplying the electrolyte, alocal or auxiliary circulation of the'anolyte, including the steps of electrolysis, passing through crystals of the 'fanolyte, filtering, extracting the entrained gases, and heating: a

28. The process of treating solutions discharged from the cathode chambers of electrolytic cells, which comprises removing the unde'composed electrolyte associated with a small amount of the product of decomposi-- tion, converting'the latter'into a purifier for electrodes. I a

the raw electrolyte, adding such raw elec-' trolyte, removing the-separated impurities, subjectingthe resulting electrolyte to the actionof theelectrodes, replenishing with a suitable salt, filtering, addlng fresh electrolyte, and then submitting to the action of the -29. The process of treating electrolytes V which comprises, subjecting the same to the actionof electrolysis in the anode chamber,-

withdrawing the anolyte, replenishing the same with asuitable salt, filtering, addingfresh quantities oi the anolyte. equal to a i the electrolyte discharged (ii-"decomposed,

and again submitting the "sael te to electrolysis, y

30. The process oftr'eating: electrolytes which comprises, subjecting the sameto the action of electrolysis in the anode chamber,

withdrawing the anolyte, replen shingand' lyte to electrolysis.

purifyingthe same,adding fresh quantities of the anolyteequal to the electrolyte dis-v charged' or decomposed, and again, sub

mitting-the anolyte, to electrolysis. 31. The process of treating electrolyte which'comprises, heatingthe same, subject-'- ing the same to the action of electrolysis in the anode chamber, withdrawing the ano- Y lyte, replenishing and purifying the same,

adding fresh quantities of theanolyte equal tothe electrolyte discharged or decomposed,

and again submitting the anolyte toelectrolysis. v 132. The process of treating electrolytes whichcomprises, heating the .same,s'1;1 bject ing'the same toithe'action of electrolysis in the anode chamber, withdrawing the anosalt, filtering, adding fresh quantities of the anolyte equal to the electrolyte discharged or decomposed, heating, and again submitting the anolyte to electrolysis.

33. The process, of treating electrolytes which comprises, heating the same, subjecting the same, to the action of electrolysis in the anode chamber, withdrawing the anoly te, replenishing and filtering thesame,

- cooling,-changing the effective specific gravlyte, replenishing the same with a suitable in the anode chamber, withdrawingthe anolytereplenishing the s h v u ble. salt, filtering, introducing air for changing the efiective'ispecific gravity, removing said air-,- removin fresh quantities of the anolyte equal to the electrolyte discharged or decomposed by athe entrained gases, adding cell, heating, and again submitting the ano- GEORGE A. GABRIEL. -Witnesses:

WALTER S. JONES, EDWARD W.- .VAILL, -J r.

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