US1440502A - Method of and apparatus for making fine metallic powders and colloid solutions - Google Patents

Description

J. SLEPLAN,

METHOD OF AND APPARATUS FOR MAKING FINE METALLIC POWD ERS AND COLLOID SOLUTIONS.

FILED JAN. 8. 1920.

. INVENTOR dose 0%) fi/ep/tm WITNESSES: 1 2% TTORNEY Patented Jan, 2, 1923,

UNHTED stares teaser PATENT @FFEGE...

JQSEPH SLEIPICAN, 0F WILKINSBURG, PENNSYLVANEA, ASSIGNOR T0 WESTINGHQUSIE ELECTRIC a MANUFAGTURING CQMIPANY, A CURPOJRAliTIQN OF PENNSYLVANIA.

JSEEETHOD @F AND APPARATUS F013 MAKING FINE METALJLXG FPQWDERS AND COLLQID SOLUTIONS.

- Application filed January e, 19%. serial It'o. 859,187. 7

To all whom it may concern:

Be it known that I, Josnrrr SLEPIAN, a citizen of the -United States, and a resident of Wilkinsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Methods of and Apparatus for Making Fine Metallic Powders and Colloid Solutions, of which the following is a specification.

My invention relates to methods of, and

- apparatus for, making fine metallic powders and colloid solutions,-and it has, for itsprimary object, the provision of an electrolytic process particularly adapted to the formation of such products.

Heretofore, various methods have been practiced to obtainfine metallic powders and colloid solutions, as, for example, by grinding or otherwise finely dividing a metal by mechanical means. These methods have been unsatisfactory for various reasons, among them being the fact that certain impurities were almost always present, because of the abrasive action between the metal being divided and the instrumentalities employed. in treating it.

According to my present invention, I may employ a suitable metal as electrodes in an electrolytic bath of propercharacter, and I may pass a current between the electrodes through the bath, reversing the direction of the flow of current at suitable intervals in such manner that the metal passing into the solution from one electrode during the flow of current in one direction is re-deposited, as

a non-adherent powder, during the flow of current in the opposite direction.

Various modifications may be resorted to in practising my invention, and electrodes of widely difierent characters may be employed. However, for the sakeof clearness, Iha've illustrated in the drawings certain preferred structures particularly adapted for the purpose. In the several views of the drawings, in which similar reference numerals indicate corresponding parts, Figs. 1 and 2 are diagrammatic sectionalviews of electrolytic cells suitable, for the carrying out of my nvention, and Fig. 3 is a transverse sectional view of a modified electrode structure.

As will be appreciated from a more careful consideration of Fig. 1 of the drawings, ll may provide a suitable container 1 for an elec-trol tic bath 2 in which are immersed electro es 3 and a. Supply conductors 5 and 6 may lead from the electrodes to any sired to obtain, and any suitable solution may beemployed for the electrolyte, the particular solution depending upon the metal constituting the electrodes. For example, 1 have prepared fine powders of copper and copper colloid solutions through the employment of copper electrodes immersed in an electrolytic bath of sodium chloride;

While bare metal electrodes may be employed, I pre'fen'in order to prevent concentration charges at the electrodes, caused by convection currents in' the electrolyte, to

screen or cover the electrodes with a suitable covering or coating of porous material, such as layers of cotton or asbestos tape.

For example, in Fig. 1 of the drawings, 1

have disclosed a suitable electrode construction comprising a tubular body 8 of copper, the wall of which may be perforated, as at 9, the portion of the body immersed within the electrolyte being provided with a porous covering 10.

In practising my invention with the type of electrodes disclosed in Fig. 1, a current of suitable density, which may approximate one ampere per square inch of electrode area, is passed between the electrodes, and its direction of flow is reversed at suitable intervals, such as from 4 to 5 seconds. these conditions, the copper passing into the electrolytic bath from an electrode during the flow of current'in one direction will be deposited upon the electrode as a nonadherent powder during passage of the current in the opposite direction, and the resultant suspension or colloid solution may be withdrawn from the interior of the electrode by a pipette or equivalent device from time to time. This colloid solution may, obviously, be treated by filtration, evaporation or equivalent means to obtain a fine metallic powder, if such is the product deslre While the electrode construction disclosed in Fig. 1 has been found to be desirable,

other electrodes may be employed. For example, the electrodes may be Bare, as indicated 'in Fig. 2, under which circumstances the metallic particles deposited will pass directly into the main body ofvthe bath em-- ployed. In likeman'ner, if. it is inconven-.-

ployed in connection with suitable electro-j lytes Without, in any way, departing from the spirit of my invention. Furthermore, the size of the deposited particles may be varied, within certain limits, by varying the density of the current. or its frequency or both. Furthermore, various re-agents,

' which beneficially affect the colloid state,

.such'as acids, bases, protective colloids and the like, may be introduced to the. electrolyte-at or near the electrodes to facilitate ciated that m the formation of the desired fine metallic powder or deposit.

In view of'these facts, it will be -a preinvention. is capable o numerous modi cations and, consequentl I do not wish to be, in any way, restricte ex-' cept in such respects as are ind cated in the appended claims.

I claim as my invention v 1. The method of forming fine metallic powders and colloid solutions that comprises providing metallic electrodes, passing a lowfrequency current between 'sald metallic electrodes immersed in an electrolyte. I

\ reactor;

2. The method of making fine metallic powders and colloid solutions which comprises providing metallic electrodes with porousscreens and passing a low-frequency current between the electrodes while they are immersed in an electrolyte.

3. The method of forming metallic powders and colloid solutions that comprisess providing metallic electrodes with a porous coverlng, lmmerslng the electrodes in an.

electrolyte,'connecting the electrodes in circu1t w1th a source of direct current and reversmg the ein ection of flow of the current at intervals.

' 4. The method of forming fine metallic powders and colloid solutions which .com-

prises providing metallic electrodes, passing a direct current between saidmetalhc elec-fl jj trodes immersed in an electrolyte, reversingjfio the flow of current at intervals, fregulat ing the currentv density.

5. An apparatus for use in the. formation of metallic powders and colloid solutions that comprises an electrolytic bath and metallic electrodes provided with porous coverings immersed in the bath.

6. An a paratus for use in the formation of metallic powders and colloid solutions that comprises an electrolyte, and tubular metallic electrodes immersed therein, '-and provided with porous screens.

7. An apparatus for use 1n the forming of metallic powders and colloid solutions that comprises; an electrolyte and electrodes immersed therein, each electrode including a tubular perforate body of metal provided with a porous covering.

In testimony whereof, I have hereunto subscribed my name .th's 31st day-of December 1919.

I JOSEPH SLEPIAN.

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