US442332A - Electrolytic apparatus - Google Patents

Description

(No Model.)

I. L. ROBERTS.

ELECTROLYTIC APPARATUS.

No. 442,332. Patented Dec. 9, 1890.

I IVENTUHG 'ATTDRNEY$.

WITNESSES:

UITEI) STATas PATENT OFFICE.

ISAIAH L. ROBERTS, OF BROOKLYN, ASSIGNOR OF ONE-HALF TO THOMAS II. MCGRAV, OF POUGI-IKEEPSIE, NEV YORK.

ELECTROLYTIC APPARATUS.

SPECIFICATION forming part of Letters Patent No. 442,332, dated December 9, 1890.

Application filed July 13, 1888.

.T all whom it Ina/y con-corn.-

Be it known that I, ISAIAH L. ROBERTS, a citizen of the l'nited States, residing at Brooklyn, in the county of Kings and State of New York, have invented certain new and useful Improvements in Electrolytic Apparatus, of which the following is a specification.

IIeretofore attempts have been made to decompose metallic salts or to purify certain solutions by electrolysis; but they have not been successful, for the reason that the apparat us employed has not been of the proper character to secure the results sought.

In the attempts heretofore made an electrolytic vat or tank has been employed with the anode and cathode in some instances in the same chamber, in others with the anode and cathode separated byan ordinary porous diaphragm. The reason for the failure of these devices as a means for decomposing metallic salts for the production therefrom of alkalies or alkaline hydrates is their inefficiency in preventing the recombination of the products of decomposition.

My invention differs from these in this respect. I employ a diaphragm or partition between the two electrodes or electrode-compartments, which, while it is impervious to the solutions and prevents their didusion or intermingling, will interpose practically no obstruction to the desired electrolytic action. Diaphragms of this character I designate electrolytic diaphragms, for the reason that they appear to be capable of acting themselves as electrolytes, and I have used them in galvanic batteries; but I have made the discovery that they may be employed in. the electrolysis of metallic salts with the results above noted. In this way I am enabled to obtain better results than are possible with any other means or process known to me. For instance, by using a decomposable anode, or one that will chemically combine with the acid radical set free by electrolytic action, I may readily and economically obtain at a single operation, by the decomposition of a me tallicv salt, an alkali and another metallic salt, both chemically pure, provided the materials used are pure.

As an example, to produce caustic soda and chloride of iron I use a suitable receptacle Serial No. 279,852. on model.)

divided by a non-porous partition or diaphragm, as above described. On one side of the partition or diaphragm I place a solution of common salt, (chloride of sodium,) with a cathode of any conducting material, such as iron or carbon, that will not be readily attacked by the resultant products of the electro-decomposition. On the other side I place an anode of iron in water containing suflicient 6o chloride of iron (a small quantity will answer) to make it a good conductor. It then a current be passed through the cell from the side of the anode or compartment inwhich it is intended to produce chloride of iron to the cathode or compartment in which it is intended to pro duce the caustic soda, the following action takes place: The dissociation of the elements by the electric action has a tendency to deposit metallic sodium upon the cathode, while the chlorine radical is transferred to the anode and there-unites with the iron, forming chloride of iron. As it is impossible to deposit mctallic sodium in the presence of water, the sodium splits or decomposes an atom ot water,and thus produces sodium hydroxide, (N Ol'L) which will be chemically pure if the salt used was originally pure and the diaphragm of such composition and character as to prevent the diffusion or intermingling of So the liquids on its opposite sides. So in like manner the sulphate, nitrate, bromide, oxide,

or other salt of any metal may be produced at the same time with all the alkaline hydrates by using the appropriate salts on one side and the proper anode on the other side of the partition or diaphragm.

If it is not desired to produce alkalies, then metals may be deposited. For instance, using sulphate of iron with the cathode and an an- 9 ode of copper, metallic iron will be deposited upon the cathode, while the transferred acid radical combines with the copper of the anode and forms sulphate of copper on the side of the anode. The said radicals, liberated by electrolytic action, cannot be kept separate from their bases without some form of par tition or diaphragm, their natural tendency being to reunite and precipitate hydrates when alkalies are obtained, or to deposit metal I on the cathode where metallic salt-s capable of deposit are produced, and while the employment of any partition contributes more or less to maintaining their separation, according to its degree of porosity, yet I have made the distinct discovery that this separation may be maintained complete by making an electrolytic diaphragm of a non-porous character. Such diaphragms or partitions I have made partially or wholly of jelly-like or gelatinous substances of various kinds, that which I prefer being made in the following manner:

I take a cup, plate, or sheet of very porous or fibrous character, such as baked earthenware or thick felt, and I saturate it by soaking it for several hours-the longer the bet- I terin an aqueous solution of alum. I then immerse it in a solution of an alkali, such as caustic soda, until by the action of the same upon the alum the pores of the porous cup or plate are filled with a gelatinous mass; or I may soak the cup in an aqueous solution of silicate of soda or potash, which should be just thin enough to enable it to penetrate the pores of the cup or plate. Then when the cup is'thoroughly saturated I dipit, say, for

an hour inmuriatic acid or the salts of a metal which has chloride of iron. These substances cause the silicate to deposit silica in the form of a gelatinous mass in the poresof' the cup or plate.

The diaphragms or partitionsm-ay be made in many other ways and of various other materials, some of which are described in pat-- ents gran ted to Henry L. Brevoort and myself jointly for improvements in galvanic batteries, in which the same or similar diaphragms or partitions are made use of.

My present invention, however, is not directly concerned with these details, being in this respect based upon the discovery that there may be interposed between the electrodes a diaphragm or partition which will prevent the dilfusion or intermingling of the fluids on its opposite sides, provided it forms in itself an electrolyte orv connecting-link, through which the electrolytic action can take place, and that thus the most useful results are obtained. Such a diaphragm forms a non-porous substantially solid homogeneous wall Whose particles, while sufficiently solid and compact to maintain their own positions and so prevent for practical purposes any transmission or diffusion of fluids between or through them, are yet themselves able to act as electrolytes and suffer such decompositions and recombinations to take place as are essential to the electrolytic action by which the result stated is accomplished.

In the accompanying drawing I have shown a conventional form of electrolytic cell, by means of which my process may be carried out.

A is the tank or receptacle; B, the non-porous electrolytic diaphragm or partition, shown in this instance as a porous cup or jar.

G is the cathode and D the anode in the porous cup.

This process is practically useful and valuable as a means of producing cheaply and in apu re state caustic soda, and incidentally a metallic saltfor example, chloride of iron; but my invention is not limited to the use or treatment of the materials specified herein, nor to any others in particular which in their nature are similar thereto. Furthermore, I regard as immaterial to the invention the specific form or character of the tank and devices by means of which the process is carried out. I may use any form of diaphragm which, While preventing the difiusion or intermingling of the fluids on its opposite side, Will not prevent nor injuriousl y retard the electrolytic action.

\Vhat I claim is 1. An electrolytic apparatus for the decomposition of metallic salts, consisting in the combination, with a tank or vat, of an anode and cathode and an intermediate non-porous electrolytic diaphragm or partition, as set forth.

2. In an electrolytic apparatus for decomposing metallic salts, the combination,with the electrodes, of a non-porous diaphragm or partition interposed between the electrodes and composed in whole or in part of a body capable of acting as an electrolyte, as set forth.

In an electrolytic apparatus for decomposing metallic salts, the combination, with a cathode and an anode decomposable by the transferred acidradical, of a non-porous diaphragm or partition between the electrodes and composed in whole or part of a body capable of acting as an electrolyte.

- ISAIAH L. ROBERTS.

\Vitnesses:

RoBT. l-l. DUNCAN, PARKER N. PAGE,

FRANK B. MURPHY.

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