US680191A - Electrolyzing salts of alkali metals. - Google Patents

Description

Patented Aug. 6, I901.

I E. A. ALLEN &. H. K. MOORE. ELECTROLYZING SALTS 0F ALKALI METALS.

(Application flled out; 22, 1897.)

(No Model.)

' INVENTEI E. Z JLW UNITED STATES PATENT Y OFFICE.

EDWARD A. ALLEN, OF RUMFORD FALLS, MAINE, AND HUGH K. MOORE, OF LYNN, MASSACHUSETTS, ASSIGNORS, BY MESNE ASSIGNMENTS, TO MOORE ELECTROLYTIC OOMPANY OF PORTLAND, MAINE, AND BOS- TON, MASSACHUSETTS.

ELECTROLYZING SALTS OF ALKAL| METALS.

SPECIFICATION formingpart of Letters Patent No. 680,191, dated August 6, 1901.

Application filed October 22, 1897.

To all whom it may concern;

Be it known that we, EDWARD A. ALLEN, of Rumford Falls, in the county of Oxford and State of Maine, and HUGH K. MOORE, of Lynn, in the county of Essex and State of Massachusetts, have invented certain new and useful Improvements in Methods of Electrolyzing Salts of Alkali Metals, of which the following is a specification.

This invention has relation to processes for the electrolysis of the salts of alkali metals, its object being to provide a process by means of which the electrolyte may be decomposed and the ionic productions carried off without difiusion of the ions given off at one electrode toward the other electrode.

Reference is to be had to the accompanying drawings, and to the-letters marked thereon, forming a part of this'specification, the same letters designating the same parts or features, as the case may be, wherever they occur.

Ofthe drawings, Figure 1 represents in vertical sectional View a cell embodying our invention. Fig. 2 represents what we term an automatic doser that is, the device for maintaining the solution in the cell at the proper level. Fig. 3 represents a detailed view of the grid.

Referring to the drawings, a indicates the cell, which may be constructed of iron and provided with a lining a, of porcelain, clay, any of the halogen derivatives or substitutional products of benzin, (and preferably the chlorin su'bititutional products, or graphite; or, if desired, the cell may be constructed of clay or any other substance, provided it or the lining be proof against the attack of chlorin. As shown, it is provided with a cover or dome a luted upon the top thereof and provided with an escape-duct a for the chlorin, this dome and duct being likewise lined with a substance to prevent its being attacked by the chlorin. The duct may be formed of lead, if desired, which, as known, is proof against chlorin; but if it be formed of iron it is coated orlined in itsinterior with any one of the substances mentioned above. The lower end of the cell is flanged Serial No. 656,054, (No specimens.)

and is closed by adiaphragm b, of asbestos paper or asbestos cloth, or both, there being a suitable insulation (indicated at b) between the asbestos cloth and the body of the cell, the bolts which secure the diaphragm in place being also insulated from the cell. The diaphragm being of asbestos is sufficiently porous to permit the percolation of a considerable quantity of the liquid therethrough for a purpose to be described. The cell and the diaphragm rest upon an iron grid 0, there being between the grid and the diaphragm a layer 01 of wire-sponge-that is, a number of layers of wire-clothor elsea layer formed of iron turnings or borings, matted more or less closely together, to prevent the too-easy percolation or flow of the caustic soda in solution, which is the product of the electrolysis. The cathode being formed in this way is adapted to be-saturated with liquid and to hold a considerable body thereof in its pores by capillary action.

The grid 0 is provided with legs or standards d to support it upon a deflecting-plate e, which is arranged or placed atan angle to conduct the caustic liquid to an outlet-pipe, through which it flows into a suitable tank or receptacle, (indicated at g.)

Within the cell is placed a quantity of broken carbon or graphite, which partially -fills the cell, this carbon or graphite constituting the anode or positive electrode or the current. The negative electrode or cathode the grid and the deflecting-plate, provided one end of the line through which the current passes .is attached to the said plate. The

with the anode in anydesired way, as through the body of the cell, or else it may be connected with a rod of graphite, carbon, or other suitable material extending down into the anode. The generator of electricity is indicated conventionally at h, as are the wires or lines 71. I13. Leading into the cell, so as to discharge therein a saturated solution of sodium chlorid or any chlorid of an alkali metal at substantially the plane of the top of comprises the Wire-sponge and, if desired,

other end of the line is electrically connected the anode, is a glass tube or duct 2', leading from a receptacle, (indicated at j.) This receptacle consists, preferably, of a pipe leading from a tank is, in which the solution is discharged from an elevated reservoir 7a. A float-valve is indicated conventionally at k and maintains the liquid at the same level in the tank and determines the level of the liquid in the various cells which communicate is deposited at the cathode and is converted into hydrate by the water of the solution which has passed through the diaphragm, the electrolysis of said solution being continued in the cathode until the liquid is dropped through the grid onto the tray. By reason of the cathode not being immersed in the solution, but being located below the diaphragm, there is no chance of the caustic solution difiusing itself through the electrolyte to cause the formation of carbon dioxid by the oxidation of the anode by hypochlorites produced from the hydrate. On the contrary, the cathion or hydrate solution drops from the cathode upon the tray and is conducted away.

The reaction, when the cathode is of iron borings or filings and the electrolyte is a solution of sodium chlorid, is as follows:

We do not confine our process or the use of the cell to the manufacture of caustic soda, as it and the process may be employed for other products, if desired, and consequently where we refer in the claims to sodium salt and sodium hydrate we mean to in clude their chemical equivalents.

In cells of this class as heretofore constrncted the diaphragm generally is immersed in a tank containing the chlorid solution, whereby the cathode is necessarily immersed in the saline solution also, so that the difiusion of the caustic soda through the diaphragm or porous sides of the cell into the electrolyte therein causes the formation of carbonic-acid gas therein,which impoverishes and dilutes the chlorin, whereas in our cell the cathode is not immersed in the saline solution, and therefore the caustic liquid cannot dilfuse itself through the electrolyte in the cell, but passes directly on to the deflecting-plate and the formation of carbonic-acid gas is practically obviated. This is of great importance, especially when the cell is employed in forming a bleaching material by conducting the chlorin over slaked lime,

sincethe lime has a great affinity for carbonic-acid gas and takes it up rather than the chlorin, thereby causing the character or standard of the bleach to become greatly deteriorated.

We do not herein claim the cell which we have thus illustrated and described, as it forms the subject-matter of divisional application, Serial N 0. 14,784, filed April 30, 1900, nor do we herein claim the method or apparatus set forth and claimed in our applications, Serial No. 700,337, filed December 27, 1898, and Serial No. 6,480, filed February 26, 1900.

Having thus explained the nature of the invention and described away of constructing and using the same, although without attempting to set forth all of the forms in which it may be made or all of the modes of its use, we declare that what We claim isl. The process of producing hydrate from sodium salt, consisting in bringing a solution of said salt in contact with one face of a nonconducting diaphragm of sufficient porosity to readily permit percolation, passing an electric current through said solution and diaphragm into an unimmersed cathode, causing the undecomposed solution to pass through said diaphragm thereby depositing metallic sodium in the cathode, converting the sodium into hydrate by the water of the solution which passed through the diaphragm and washing the hydrate from the cathode by water of the percolated solution.

2. The process of producing hydrate from a solution of sodium salt, consisting in placing said solution in contact with one face of a non-conducting diaphragm of sufiiicient po rosity to readily permit percolation, passing an electric current through said solution and diaphragm into an unimmersed cathode, causing the undecomposed solution to pass through said diaphragm, thereby depositing metallic sodium in the cathode, converting the sodium into hydrate by the water of the so lution which passes through the diaphragm, removing the hydratefrom the cathode by the water of the percolated solution, and continuously Withdrawing the solution of sodium chlorid and sodium hydrate, to prevent its phragm into an unsubmerged cathode in contact with the outer face of said diaphragm, said cathode being a porous layer of such thickness as to retain a considerable body of liquid in its pores, by capillary action, thereby in the first instance depositing metallic sodium or potassium in the cathode, causing the undecomposed portions of the solution to pass through said diaphragm and by the water contained therein converting the sodium or potassium previously deposited in-the cathode into hydrate and completing the electrolytic decomposition of such sodium or potassium salt as has passed through said diaphragm.

4. Theherein-described process for producing hydrate from sodium or potassium chlorid, consisting in bringing an undecomposed aqueous solution of such chlorid into contact with one face of a non-conducting diaphragm of suflicient porosity to readily permit percolation, passing an electric current through said solution and diaphragm into an unimmersed metallic cathode which holds by capillary attraction a considerable quantity of the said solution, whereby there is deposited in said cathode metallic potassium or sodium, converting said metallic potassium or sodium into hydrate by the water of the undecomposed solution in the cathode, and continuously completing in the pores of the cathode the electrolytic decomposition of the said chlorid solution and the hydration of the metal which results therefrom until the hydrate solution is greater than the capacity of the cathode to hold it by capillary action, whereby said hydrate solution flows by gravity from said cathode. v

5. The process of producing the hydrate from the salt of an alkaline metal, consisting in continuously filtering a solution of said salt througha permeable non-conducting diaphragm into the capillary pores of a spongy cathode; passing a current of electricity through said solution and diaphragm to said EDWARD A. ALLEN. HUGH K. MOORE;

Witnesses:

M. B. MAY, 0. F. BROWN.

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