US1689693A - Flotation process - Google Patents

Description

c. SHAPLEY FLOTATION PROCESS Flled Oct 13 1927 Oct. 30, 1928.

Patented Oct 30,1928.

' UNITED STATES acorns snur ny or nrsnor, camronnm.

FLOTATION PROCESS.

Application 1116a October 13, 1927. Serial in. 225,907.

The invention relates to a process of sepa- 5 tation process which is practical, simple and inexpensive to carry out, and by which it is possible to treat particles of material which haveheretofore never been successfully handled by flotation processes.

, My lnvention provides, primarily, for the successful separation of solid particles by flotation in which soap is the sole medium or reagent used. Essentially, the invention provides for contacting of ground particles of the material to be separated witha soap solution, whereby those particles having an at traction for soap are contacted with the solution to become coated or filmed by the soap, and then bringing the soap-filmed particles to the surface of a body of liquid, say water,-

Where they will remain, and from which they can be removed.

I am aware that soap has been suggested and tried in various ways and under various conditions in the art of separation of materials by flotation. However, I believe that all prior uses and proposals for using soap in this art have been uite far removed from the principles and spirit, of my present in vention. In the earlier processes referred to, the soap has been used as a 'frothing agent, and in connection with oils, acids and other substances, or so as to have .a chemical reaction'upon the particles contacted thereby. So far as I am aware, it has not been heretofore proposed to employ a soap solution as the sole agent of flotation and for separating particles with which the soap callyreacti...

The art of mineral separation by flotation, although well established and developed, has heretofore been more or less limited commercially to the concentration of minerals hav ing a metallic lustre. This is because the flotation methods which have been commercially practical have been inoperative or impractical on minerals lacking metallic lustre.

It is an object of my invention to provide a commercially practical flotation process which will include mineral lacking metallic lustre. I

Another object of my invention is to provide a flotation process which can be successfully carried out on particles of matter materially larger than can be successfully handled by the usual flotation methods.

does not chemivide a flotation. process in which the separation takes place quickly in the flotation machine.

It is a primary object of my present invention to provide a process of flotation which makes possible the practical separation of particles with the use of soap alone. In carrying out this object, I provide a process which is extremely simple and inexpen sive, and eliminates chemical reactions and complications such as have been present in flotation processes heretofore proposed.

As previously noted, one of the principal objects of the invention is to provide a method or process of flotation by which it is possible to successfully separate particles which have never heretofore been successfully separated by flotation, for example, calcium minerals and many minerals lacking in metallic lustre.

My present invention involves numerous A further object of my invention is to proother objects and features which, 'with those above mentioned,will be best and more fully understood from the following detailed description of a typical application and means for carrying out the'invention, throughout which description I will refer to the accompanying drawing showing diagrammatically an arrangement of apparatus that may be employed in carrying out the particular application of the invention which will be described.

While the invention is useful, generally, in the separation of materials or minerals by flotation, it is particularly adapted for separating or recovery of materials which do not chemically react with a soap solution, such, for example, as fluorite, rutile and corundum. It is to be understood, of course, that the invention is not intended to be limited to treatment of the particular materials given as examples. Experience has shown that the methods herein described will not float particles of certain materials, examples of which are quartz, felspar, and mica, but, as above noted, the invention has been found very successful in separating ores which could not be successfully treated by the flotation processes heretofore proposed.

For example, I may treat ore bearing fluorspar (calcium fluoride) and closely approach a complete separation of the fluorspar from etc., is found in crystalline form with quartz or other silicates, and it has not been practical by the flotation processes heretofore proposed to effectively separate this material from the undesired substances.

In ap lying my invention to the handling of ore or the separation of certain, values therefrom, the ore is first ground b any suitable means, for instance, in a mi 1 10. My invention is in many cases superior over most rocesses of flotation in that it will su essully handle ore in a comparatively oarse state. In thecase of ore bearing flu rspar, I have obtained successful separatio upon grinding the ore to pass a screen of ab ut 10 mesh. In practice, it may be desirab e to grind the ore somewhat finer, but it is unnecessary in most cases for it to be any finer than will pass a' screen of 60 mesh.

drained of the excess water; for instance, it may be passed from the grinder 10 into a dewatering tank from which it is withdrawn from the water by a scraper belt 12. The de- 5 watering tank, shown in the drawings, has an inclined part 13 over which the ground ore I is scraped from the tank by the scraper 12. This incline allows the excess water to drain back .into the tank. The primary object of 'dewatering the ground ore is to avoid dilution of the soap solution to-which the ore is next passed. The ore delivered from the dewateri'ng tank 11 in the damp or partly wet condition is delivered to a treatment tank 14 containing a soap solution. The ore is preferably introduced into the tank 14 so that it is submerged in the soap solution and thus thoroughly contacted with the solution. It is preferred to make a colloidal soap solu- 4 tion from sodium or otassium soaps and water,'-and I make a airly dilute or weak solution, say for example, a solution containing about one per cent or less of soap. I have found that the solution maybe even weaker than this; in fact, from experience, I am led to believe that there is no critical strength of solutioir necessary for the suc- Gil 'cessful operationof the invention. It seems merely necessary to have suflici'ent soap present in the solution so that the particles treated are contacted with soap to hold or retain it if possessing the proper character: istics. When I use the term weak soap solution, I mean a solution of about the character mentioned above. The quantity of soap required per ton of ore varies. In some cases, I have obtained satisfactory results with as low as two pounds of soap per ton, while in other cases, I have obtained the best results 0 with about ten pounds of soap per ton. As an example, I may state that I have carried out the process on a commercial scale on an ore bearing fluorspar using about four pounds of soap penton.

Referring to ore bearing fluorspar, which The ore, after grinding, preferably is,

water free from any reagent which wil I am citing asan example, the ore with the soa coating or filming oi the fluorspar particles with soap. The fluorspar has an attractive or the contacting of solution results in the adsorptive quality for the soap articles, which causes the soap particles to a p y thenfselves to the fluorspar particles. y obser-.

vations indicate that the soap particles merely apply or coat themselves to the fluorspar particles andthat there is no chemical reaction between the two. I have found it advantageous to apply the ore to the treat- .ment tank 14 with as little agitation as possible to keep the soapsolution quiet and thus.

the soap-absorbing properties of the particles to be separated.

The ore, after havingbeen subjected to the soap solution to allow the particles to thoroughly contact with the soap solution, is removed from the treatment tank 14 as by scraper 15. The treatment tank may e provided with an inclined part 16 over which the ore is scraped from the tank, thus allowing the solution to drain back into the tank. This method of removin the ore from the treatment tank provides for the desired removal of the ore with a minimum of agitation which, asabove pointed out, is preferably to be avoided. This manner of removin the treated orefrom the treatment tank is to "separate the excess or unused soap solution from the ore, and, if it is found that the separation is insufiicient, the ore, after leaving the treatment tank, may be given, a water wash; for instance, it may be passed through a washing tray 17. The removal of excess soap is desired as the soap may reduce the surface tension of the water on which the coated particles are to be floated. I may.

state at this point that the soap particles, when once applied to the fluorspar particles, adhere to and permanently coat or film the fluorspar so that they are not removed by ordinary water washing.

The ore, after thus being freed from the soap solution, is handled to bring the fluor-.

of act to decompose the absorbed soap, coating the separated particles. This treatment may be carried out by agitation in an ordinary flotation machine 18. The soap bearing fluorspar spar particles to the surface of a bod? a belt particles, upon reaching the surface of the 1 2. The process of separating finely dividedv body of water, will remain on the surface and will accumulate in the form of a scum. The accumulation of particles on the surface is, in fact, a scum and is not a froth as is the case with the usual methods of flotation. It will be obvious that the fluorspar articles accumulating on the surface of the ody of Water as a scum may be removed in any suitable manner; for instance, they may be allowed to flow or fall over an overflow edge 19 provided for that purpose. The separated or concentrated flu'orspar thus obtained may be received and thereafter handled in any suitable manner.

I have found by actual operation that it is not necessary to water wash the pulp or minerals after contactin them with the soap solution.- By using su cient water in the flotation machine, separate water washing is unnecessary, as the bulk of water in the machine is constantly changing and carrying away tailings. I have found that this condition dilutes the soap solution so much that the pulp needs no washing after being contacted.

Having thus described the invention, what I claim is: a

1. The process of separating finely divided particles y flotation comprising contacting the particles with a soa solution which does not chemically react with the particles, and then bringing the particles to the surface of a bod of water free from any reagent which woul decompose the soap.

particles by flotation comprising contacting the particles quietly with a soap solution which does not chemically react with the particles, and then bringing the particles to the surface of a body of water free from any reagentwhich would decompose the soap.

3. The rocess of separating finely divided particles flotation comprising contacting the partic es with a soap solution of a strength to satisfy the soap absorbing pro erites of the particles and then bringmg t e particles to the surface of a body of liquid free from any reagent which would decompose the soap.

4. The rocess of separating finely divided particles y flotation comprising contacting the particles with a soap solution, separating the particles from the solution including washing the particles with water, and then bringing the particles to the surface of a body of liquid free from any reagent which will decompose the soap. Y

5. The rocess of separating finely divided particles y flotation comprising contacting the particles with a soa solution which does not chemically react with the particles, separating the soaped particles from the solution including washing them with water, and then bringin the soaped particles ,to the surface of a odly of liquid free from a reagent which wil decompose the soap.

In witness that I claim the foregoing I have hereunto subscribed my name this 8th day of October, 1927.

COOPER SHAPLEY.

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