US1486546A - Electrolytic separation - Google Patents

Description

March 11, 1924.

Filed May 26. 1922 2 Sheets-Sheet l M, M, K MW H r v 0 4 n f 9 vi] +ma |||l ural- :T i il O All;

2 Sheets-Sheet 2 wail/W ATTORNEY March 11,1924.

B. E. F. RHODIN ELECTROLYTIC SEPARA'TION Filed May 26 1922 9 w m m m n W H w v V r 5 h l atented Mar. 11, 1924..

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Application filed May as, 1922;. Serial no. scares.

, To all whom it may concern:

Be it known that I, Bnonnn E. F. Rnonnv a subject of the King of Great Britain, and a resident of Atlantic City, count of Atlantic, and State of New Jersey, ave invented certain new and useful Improvements in Electrolytic Separation,- of which the following is a specification.

This invention relates to the art of-electrolytic decomposition or separation such as practised in the manufacture of magnesium, sodium and potassium.

One of the problems experienced in such work has been to effect a practical separation of the products released at the anode and cathode and to prevent a recombination of the same. Various expedientshave been proposed. In the earlier forms a solid diaphragm of insulating materialwas interposed between the electrodes and the action ,took place about the lower edge of such barrier. This structure. was modified. by providing straight passages therethrough. This modification reduced the -mechanical and electrical resistance, but as with the former did not prevent re-combination. By a further modification. the passages were sloped downwardly, away from the anode side of the partition to prevent outflow of the gases but this construction ofiered no check to the inflow of material released at the cathode and so did not prevent rccombination of the elements. Porous diaphragms also have been proposed, but these are inefiicient, because of their high mechanical and electrical resistance, necessitating fill)? use of higher voltages than'are desir a e. 1

The objects ofrmy invention are to overcome the present 'diflicultiesin the art, in-

eluding those above enumerated, and to ef--.

feet a free decomposition and complete or substantially complete separation, without re-combination; and further, to accomplish the same with low voltage and relatively high ampere hour efliciency. v

The foregoing and" other objects are attained in my invention 'by certain novel .features ofv construction, .combination and relation of parts, as will be clear-from the following specification, which is to, be read in conjunction with the drawings accompanying and forming part of the same.

Figure 1 in the drawings referred to is a plan view of an electrolytic cell construct ed in accordance with and embodying features of the invention.

Figure 2 is a vertical sectional view of the same as taken on substantially the plane of line 22 of Figure 1.

Figure 3 is a horizontal sectional view as taken on substantially the plane of line 3-3 of Figure 2.

Figure 4 is an enlarged broken sectional view illustrating a modified sectionalconstruction of the partition'which in this case is cylindrical in form to surround a centrally located anode.

Figures 5 and 6 are plan and vertical seetional views respectively of another form of the invention, in which the body of the cell is of metal and itself forms the cathode.

In the form'of the invention first show the electrodes consist of a centrally locat anode 7 surrounded by a series of cathode elements 8, all being mounted in the insulating support 9 constituting a cover to the vessel 10, which is constructed to contain the fused electrolyte.

. In the case of magnesium separation, the electrolyte usually consists of a bath of mixed chlorides of magnesium andpotassium or magnesium, potassium and sodium maintained in properly fused condition. This bath is kept substantially constant by supplying magnesium chloride, as requir .the anode in the present disclosure being constructed for this particular purpose by providing it with a feed passage 11 therethrough, terminating at the lower end in a series of slots 12 forming distributing channels.

Interposed between theelectrodes of opposite polarity is a barrier or partition 23' of non-conducting material such as alundum or the like, this'barrier in the present disclosure taking the form of a cylinder surrounding the anode and thereby forming within the cell outer and inner concentric chambers. In the example under discussion, where magnesium is being produced, the magnesiuni is released in the outer chamber and the chlorine is released'in the inner chamber, the first in the form of a metal and the second in the form'of a gas. The bath be- I ing of greater specific gravity, both these elements will rise to the surface, the mag nesium collecting and being removed ordinaril from time to time and the gas being suitably conducted away.

For eflicient operation the electrolyte should have free access to the electrodes of opposite polarity. To allow for this and at the same time hold apart the elements liberated at the cathode and anode, the partition is constructed with electrolyte passages therethrough, each having a dip or depression intermediate the opposite ends of the same to thereby provide positive stops against the flow of lighter materials from both sides of the partition. In the present illustrations these electrolyte passages are of substantially V-shape as shown at 13, with sharply angled end portions inclined downwardly from the opposite sides of the partition. These sharp downward bends, it will be seen, often no impedance to the electrolyte, but do oppose and prevent the lighter materials assing therethrough. The chlorine gas, in t e example under consideration, is thus trapped within the cylindrical inner chamber and the magnesium metal is in the same fashion caught and held within the outer chamber.

The number and size of the electrolyte passages may vary to suit difierent conditions. As an example I have shown in Figure 4 how these passages may be in the form of arcuate slots extending partly about the periphery of the cylinder. Also in the figure referred to ll have shown how the cylinder may be made up in cylindrical sectrons 14, set one on top of the other, formed at their upper edges with trough-like grooves 15 and at their lower edges with corresponding pointed projections 16 cooperating when the units are assembled to form the electrolyte passages, substantially V- shaped in cross section. To position these units so that the intermeshing parts de-' scribed will properly register to form the passages, l[ have shown them as having cooperating tongue and groove engagement, as indicated at 17. 1

To facilitate removal of the collected material from the outer chamber I have shown the cover as having a removable section 18 and the escape of the gas from the inner.

chamber is here provided for by constructing the anode with a gas outlet passage 19.

The containin vessel is shown in Figure 2 as construct/e with a centrally located well 20 for the collection of im urities, this well being closed in by the cylindrical partition which isshown as resting upon the bottom of the vessel about the periphery of this well.

The structure of Figures 5 and 6 is gener-' ally similar to that described, the main distinction being that the containing vessel is made of metal and'used as the cathode electrode, it having a suitable terminal 21,

by which the necessary electrical connections can be made thereto. Also in this case the collection well 20 is provided in the bottom of the vessel by placing the lowermost electrolyte passages in the partition a sufficient distance above the lower end of the same to form a substantial chamber, the bottom of which may be provided by an insulating block 22 on which the cylinder rests.

With this invention because of the greater freedom and accessibility of the electrolyte to both electrodes good conductivity is provided, the electrical resistance is reduced to a minimum and consequently, the cell can be operated at much lower voltage than has heretofore been practicable. Also there are no losses due to re-com'bination and hence. the cell can be operated at high ampere hour efiiciency and consequently, with relativelylow power consumption.

What I claim is:

1. In electrolytic separation, an electrolytic cell having electrodes of diflerent polarity separated by a partition of insulating material constructed with electolytic pas sages therethrough, each inclined upwardly at lts opposite ends to hold back the lighter products released-at the different electrodes.

2. In electrolytic separation, an electrolyt c cell having electrodes of different polarity separated by a partition of insulatmg material constructed with an electrolytic pa'ssage therethrough with a downwardly ofi'set portion intermediate the ends of the same to hold back the lighter products at both sides of the partition.

3. In electrolytic separation, an electrolytic cell having electrodes of opposite polarity and an insulating barrier separating said electrodes and rovided with passa es therethrough, each ormed with a dip 1ntermediate the ends of the same so as to hold back the lighter products at both sides of the barrier.

4. An electrolytic cell having electrodes separated by a partition of insulatin material formed with substantially V-s aped passages therethrough having sharply inclined reversel sloping portions for holding back the ighter products at opposite I messes electrodes of difierent polarity entered in said hath end a partition of insulating material between said trolyte passa s with means r electrodes having electherethrough provided reventing flow therethrough in either irection of the lighter products resent. at the opposite sides of h i artition. herein disclosed process of electrolytic separation which includes maintaining a hath of fused electrolyte substantially continuously between ananode'and cathode and at the same time separating and preventing recombination of the final products 0 electrolysis.

8. The herein disclosed process of elec trolytic separation which includes maintaining a bath of fused electrolyte .in continnons communication between el trodes or opposite polarity while separating and preventing recombination of the l priednets of electrolysis.

9. In an electrolytic cell, a partition of insulating material consisting of built-n sections resting one on the other and form at their adjacent edges with parts provid ing passages therethrou h. H

10. The structure of c aim 9 in which said passages each have oppositely inclined end portions.

11. An electrolytic cell having electrodes of opposite polarity and: a barrier of alondnm separating said electrodes but provided with electrolytic passages therethron h each formed with adip intermediate t e ends of the same so as to hold hack the lighter products at both sides of the barrier.

li'n wltness whereof, l have hereunto set my hand this 18th day of May, 1922,

BRQDDE E. F. RHUDIIN.

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