US1569484A - Process and method of disintegrating metals in a ball mill or the like - Google Patents

Description

Patented Jan. 12, 1926.

UNITED STATES PATENT OFFICE.

GRAIING COMPANY, INC., OF NEW YORK, N. Y., .A CORPORATION OF NEW YORK.

PROCESS AND METHOD OF DISINTEGRATING METALS IN A BALL MILL OR THE LIKE.

No Drawingm Application filed March 25, 1919, Serial No. 285,055. Renewed June 3, 1925.

To all 7.0120711 it may concern.

Be it known that I, Evnnn'r'r citizen of the United States. residing at Passaic, in the county .of Passaic and State of New Jersey, have invented certain new and useful Improvements in Processes and Methods of Disintegrating Metals in a Ball Mill or the like, of which the following is a specification. v

This invention relates to the reduction of metals to a finely divided condition in the nature of a dry powder or dust, in which the individual particles are in the form of minute relatively flat flakes, such as may be' used for the production of metal paint ,etc.

The practice of the invention may involve a preliminary disintegration of the metal. and then subjecting it to the mechanical ac tion of steel balls or the like in an ordinary ball-mill, whereby. disintegration is completed to the desired fineness.

One of the objects of the invention is to facilitate, in a mechanical sense, the breaking up of the particles of metal into smaller particles without relative loss of the fiat surface of the particle, and whereby the time and the power consumed in the disintegration are greatly reduced.

A further object is to conduct the disintegration aforesaid with the particles of the metal under treatment well covered with a liquid in the nature of an oil or its equivalent, this liquid having the property (1) Of protecting the metal under treatment against the eifects of atmosphere dnr-, ing the disintegration, as for instance oxidation, explosion and the like;

Of lubricating the metal particles so that the reduction of them by the balls or other disintegrating means is more easily and quickly accomplished;

(3) Of forming with the metal particles,

a mixture like a cream, sludge, or emulsion which is tenacious, cohesive and adhesive, and resistant to separation or segregation of its constituents and to the destruction of it own continuity, and which accordingly maintains a substantially uniform, continuous and homogeneous character during the disintegration, a mixture in which the tendency of the metal particles to settle out is minimized; I

(4) Of constituting a vehicle for the metal particles which will adhere evenly to the surfaces of the mill and of the balls by J. HALL, a"

the met means of which the reduction or disintegration is carried on, so that from the im act of ball against ball or ball against m1 l-wall at any point there will .alsoresult the flattenmg or reduction of a particle or particles of metal carried in the oily sludge or cream, the opposing surfaces,

WhlCll over-spreads the sludge being of such Wlll coat the balls, but; not so thick as to unduly cushion the blow of the balls when they come together or strike the mill-wall;

(5 Of having a boiling point sufliciently consistency that it during the disintegrating process, but not so high that there will be difficulty in removing it completely later on when the disintegration has been finished;

(6) Of being chemically inert, throughout the operation, to the metal under treatment, and preferably also non-inflammable;

being easily removed by eva oration from the metal particles after disintegration is completed, but leaving the ticles with a coating of grease.

Still another, and more specific, object of the invention is to provide a protective vehicle or covering for the metal particles while they are in a ball-mill or the like and for the attainment of the object last-above final reduction or comminution can more readily be carried on, as by turning it down in a lathe, whereby to produce chips or shavings of a size to facilitate further reduction. During this preliminary reduction the metal may be maintained entirely covered with a liquid as hereinafter described, a convenient way .of accomplishing this being to immerse the metal and cutter 1n a bath of the li uid. To insure that the liquid shall not reach oilmg or decomposition temperature on account of the heat necessarily speed production,

quantity. The final reduction is accomplished referably in a ball-mill, in which al particles are subjected to the hammering action. of ball against ball and ball 0 high to prevent extensive loss by vaporiza-' par- resulting from highit may be continuously renewed, or initially supplied in sufiicient against mill-wall. During this operation the metal is kept well covered with a liquid having the roperties above set forth. I have had- 00 results with a mixture of varnoline a petroleum fraction oil with a boiling point between 307 and 405 F), and stearine, in the proportion (assuming that there is 1.5 lb. of metal, as copper, under treatment) of 0.75 lb. of varnoline, 50.00 lb. of balls, and stearineabout 0.33% of the weight of copper. I This liquid protects the metal against the effects ot'atmosphere, lubricates the particles so that their further reduction is facilitated, carries and supports the particles by reason of its creamy consistency, against the tendency of the particles to settle out and separate, and adheres evenly to the surfaces of the mill and of the balls, so that from the impact of ball against ball, or ball against mill-wall at any point there will result the flattening or reduction of a particle or particles of metal carried in the oily vehicle which over-spreads the opposing surfaces. This liquid has a boiling point suiiiciently high to prevent extensive loss by vaporization during the disintegratin process, but not so high that there will be difiiculty inremoving it completely later on when the disintegration has been finished. The liquid is chemically inert to the metal under treatment and to the metal of the mill and the balls, and may substantially non-lnflammable b tion of suitable chemicals, as or instance carbon tetrachloride.

Upon completion of disintegration the contents of the mill are subjected to evaporation, preferably under conditions of vacuum, so that the varnoline goes off at a comparatively low temperature, thus minimizing the danger of the metal catching fire on removal from the dryer while hot. In the process of vacuum drying, of course, the distillate may be recovered for re-use. After the oil has all gone oil, the stearine remains in the shape of a coating on the particles. Such a coating is believed to be desirable where the powder is to be used for decorative purposes.

I prefer to use polished steel balls in the milling operation, because I have found that roughened balls tend to break up the metal particles without flattening them to the de sired extent. a

It will be appreciated that as the disintegration of the metal proceeds, the total surface area of the metal particles is enormously increased and for that reason I may begin the disintegration with a .suflicient amount of the liquid and add other additional quantities of varnoline or stearine, or both, at intervals as the disintegration goes on. And when the disintegration has been carried out to the desired extent I---may add a considerable amount of the varnoline in order to make the contents of the mill more if desired be renderedthe addi{ fluid and utilize the liquid as'a vehicle for carrying the metal to the filter and/or dryer,

where of course the oil is driven 0E and recovered for re-use.

In grinding the metal it is apt tobeeom e.

warm due to the mechanical action, and if the liquid has not been rendered non-inflame mable there will be a -short interval of time when there is a possibility of explosion of the oil vapors, if there is-access ofatmosphere. To obviate the possibility of such 3.1;,

explosion I contemplate exhausting the air from the mill, its place being takenb the oil vapors which will be given off. r of course a simple remedy will-be to make the liquid non-inflammable or to use a non-inflammable liquid in the first instance. Furthermore, I contemplate keepingdown the temperature of the'mill during operation by a spray of cooling water or the like. In the case of continuous grinding, that is, where the oil and metal are fed and discharged continuously and the oil returned after being separated from the metal, the temperaturemay be maintained by some outside cooling means, or by circulation through pipes which are air cooled or water cooled, or any other desirable means. While this cooling is not strictly essential to operation, it doesundoubtedly lessen the risk of firel'n the case of inflammable liquids, and prevents loss of liquid from evaporation whether the liquid is inflammable or non-inflammable.

I claim c .1. The art of manufacturing metal dust which consists in mechanically disintegrating the metal, while keeping it covered with i by vaporization; and thereafter freeing the.

disintegrated material from the liquid by evaporation of the liquid, to produce a dry metallic powder.

2. The art of manufacturing finely divided metal in the form of minute relatively fiat flakes, which consists in subjecting the metal to the action of a ball mill or the like, while keeping it covered with a lubricating liquid which protects the metal against the eiiects. of atmosphere and is inert to the metal, and which has a boiling point high enough to prevent excessive loss by vaporization during the disintegration, but not so high that there will be diiiiculty in its separation later from the metal by vaporization; and thereafter evaporating the liquid from around and between the particles to produce a dry metallic powder.

3. The art of manufacturing finely divided metal in the form of minute relatively 'fiat flakes, which consists in subjecting the metal to the action of a ball mill or the like, while keeping it covered with a lubricating 1i uid which protects the metal against the eli ects of atmosphere and is inert to the metal, and which has a boiling point high enough to prevent excessive loss y vaporization during the disintegration, but not so high that there will be diificultyin its separation later from the metal byvaporization, preventing decomposition of the liquid during the disintegratiomland thereafter evaporatng the liquid from around and between tlhe particles to produce a dry metallic power. 7

4. As a step of the process of disintegrating metals in a bell-mill or the like, keeping the metal under treatment covered with a liquid consisting of a avin 'a definite boiling with the metal particles, in the operation of the mill a homogeneous mixture like a thick cream, sludge or emulsion which is tenacious, cohesive and adhesive and resistant to separation or segregation of its constituents and to the destruction of its own continuityand which maintains a substantially uniform, continuous and homogeneous character during the disintegration.

5. The method of disintegrating metal in a ball mill or the like which comprises keeping the metal well covered with a liquid com rising a large proportion of a relatively point which forms rea ily vaporizable oil, and a small proportion of a grease having a boiling point higher than that of the oil, and when the disintegration is completed, driving off from the metal particles the v readily vaporizable oil without disturbing the grease.

6. As a step in the process of disintegrating metals in'a ball-mill or the like, keeping the metal particles well. covered with a liquid cheniically inert to the metal and having a boiling point smfiiciently hi h to prevent extensive loss by evaporization uring the disintegrating girocess, but not so hi h that there will be di culty in removing it completely plurality of ingredients against ball or ball against mill-wall at any point there will result the flattening or reduction of a particle or articles of metal carried in the sludge whic over-spreads the opposing surfaces, the sludge being of such consistency that it will coat the alls, but not so thick as to unduly cushion the blow of the balls when they come together or strike the mill-wall; and eflectin se aration of the metal particles from t e liquid after the disintegration has been com leted, to leave the metal particles in a su stantially dry state.

7. The method of disintegrating metals, consisting'of the steps set forth in claim 3 with the additional step of adding a sufficient amount of oil to the contents of the mill when the disintegration is completed necessary for carrying the metal particles out of the mill.

8. The process of manufacturing metal powder which-consists in mechanically disintegrating metal, while kee ing it covered with a lubricating liquid which protects the metal against the effects of atmosphere and is inert to the metal, and which has a boil ing point high enough to prevent excessive loss by vaporization during the disintegration, but not so high that there will be difficulty in its separation later from the metal by vaporization.

In testimony whereof I afiix my signature.

EVERETT -JOEL HALL.