US1869532A - Process of separating ore - Google Patents

Description

1932a A. J. WEINIG 1,869,532

PROCESS OF SEPARATING ORE Filed Oct. 4, 1927 CONDITIONING CONDITIONING FLOTATION MACHINE CONCENTRATE CONCENTRATE CONCENTRATE I mLmI m CONCE NTRATING T BLES ETC.

TAILINGS amma Io:

. a f 55134 flf tomam s CONCENTRATES Patented AugtZ, 1932 UNITED STATES PATENT OFFICE ARTHUR J. WEINIG, OF GOLDEN, COLORADO, ASSIGNOB TO THE AMERICAN METAL COMPANY, LIMITED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK :enocnss or snrm'rmo on:

Application fled October 4, 1927. Serial No. 223,876.

This invention relates to process of separating ore, more specificall to processes for separating ores or the like by means of froth flotation and the like. v

The separation of the various minerals contained in certain types of ore by selective flotation has heretofore been a troublesome problem. It has been found that by adding certain reagents to the crushed ore the elimination of certain elements could be materially improved but no general treatment has heretofore been devised whereby the general selective differentiation of the respective minerals could be brought about in an eflicient and economical manner, and more particularly by conditioning prior to separation.

One object of the invention is toprovide a more effective and economicaLdifierentiation of the comminuted materials. Another object is to accelerate the process of separation.

Further objects of the invention will more fully appear from the following description taken in connection with the accompanying drawing illustrating diagrammatically, by way of example, suitable apparatus used for carrying out the process.

The invention consists in the method andin the steps of carrying out the method as herein more fully described by way of example, according to certain preferred ways of practicing the same, and in connection with suitable apparatus for carrying out the same; and the invention will be more particularly pointed out in the appended claims.

I have discovered that extremely beneficial and economical results are obtained, in connection with separation by flotation, by treat ing the crushed ore with a gas containing oxygen, prior tothe time of adding agencies, such for example as the emulsifying or frothing agents, which are suitable for effecting flotation of the unoxidized particles of the minerals. This enables a selective differentiation of the respective minerals to be brought about in an eflicient and economical manner.

Before giving a detailed description of a specific embodiment of the invention, a. brief description'will be given describing the process in general.

The ore tobe treated is crushed in any suitable manner, such for example as by grinding, either while dry or moist, and is then preferabl diluted with water to the proper degree. he moist ore is then pretreated or conditioned by being subjected to agitation and while agitated is treated with a gas containing oxygen; the time of treatment depending upon the degree of activity of oxygen 1n the gas employed, and being of sufiicient duration to alter the surface of those particles which it is desired to inhibit or retard the flotation of, such for example as with the froth in the subsequent flotatlon step or steps. This alteration of the mineral particles need not completely decompose nor chemically change the whole of the particle; the development of a film on or around the surface of the particle is suflicient to render the particle unresponsive to the froth-forming agencies suitable for unaltered or less altered particles of minerals; it being understood that the film or films may or may not be so thin as to be beyond the power of present scientific resources to measure and that it may or may not be of a sufiicient thickness to change the shape, color or lustre of the particles.

I have found that this conditioning treatment may be effected b forceful aeration using ordinary air as t e aerating gas, and such treatment has been found to require a treatment period of from several hours to "several days according tothe ores treated and the results desired. I have further found that a great saving of time and a more efiicient means is to produce ozone or ozonized air and condition? the ore with this gas by forceful aeration. And I have further discovered that a treatment which is possibly I to be more particularly described hereinafter.-

While air per se is the cheapest gas containlng oxygen, nevertheless, due to the length of time required to treat the ore, it has been found to be more economical to use a gas containing oxygen more active than in air, suchv 7 indicated.

Referring to the drawing Fig. 1 shows'a flow sheet diagram illustrative of the process as carried out when flotation separation is utilized with ozonized air as the pretreating or conditioning reagent,

Fig. 2 shows a flow sheet diagram illustrative of the process as' carried out when table concentration is utilized with the same reagent,

Fig. 3 shows in more or less diagrammatic form and partly in section apparatus adapted to be used in connection with theconditionin g ste of the process when ozonized air is used,

ig. 4 shows a modified form of a part of the apparatus shown in Fig. 3, and

Fig. 5 shows in a more or less diagrammatic form, and partly in section, apparatus ada ted to be used in connection with the con itioning step of the process wherein oxygen is used as the conditioning gas and-more specifically where the oxygen is produced by electrolysis of the pulp water.

Referring to the drawing and more partitcularly to Fig. 1, the step indicated as conditioning may be carried out by a device or devices adapted to thoroughly mix the ore pulp with the conditioning agent. The apparatus shown in Fig. 3 or Fig. 4 may serve for this purpose, but it is to be understood that the invention is not limited to the specific apparatus shown.

In the present embodiment of the invention, and for purposes ofillustration only, ozonized air is used as a conditioning agent which is applied in such a manner-that practically all of the solid particles of the crushed ore come into intimate contact with it. The conditioning treatment is continued until the desired results are obtained as will be more fully described later, and the duration of this treatment will vary with different ores and with the results desired; all of which will be well understood by those skilled in the art.

Apparatus for carrying out the stepsof the process following the conditioning treatment are so well known in the art that it is not deemed necessary to show the specific apparatus for this part of the process. Any

suitable apparatus may be utilized for this purpose as is well understood in the art. I

Referring to Fig. 3: the apparatus shown in the present embodiment comprises a conditioning mixing tank 1 provided with mechanical agitating means such as the pad-v dle 2, which is attached and driven by the rotatable shaft 3 supported in suitable bearings tral bore in the shaft 3 with a pipe 7 which has a running connection on one end with the shaft 3, and is attached at the other end to the outlet of an ozonator 8. An outlet pipe 9 is connected at the bottom of the tank 1 providing an outlet therefrom and is provided with a valve 10 adapted to close the pipe 9.

Other apparatus may be used for this treatment wherein mechanical agitation is not depended upon. For example, Fig. 4 shows a modification of the conditioning apparatus wherein pneumatic agitation is used. In this modification the tank 11 is provided with suitable means for introducing gas into the contents of the tank in a finely divided condition; such for example as by the use of a felt or canvas pad 12 supported on a screen 13 which is suitably mounted as by a supporting -grid.14. The pad 12 and its supporting members are positioned above the bottom of the tank 11, thereby providing a space for the admission of the gas; and this space is in communication with an inlet pipe 15. provided with a suitable check valve 16 adapted to allow the admission of the gas and to prevent the passage of the contents of the tank out through the pipe 15. The pipe 15 in the present embodiment corresponds to the pipe 7 in Fig. 3, and hence when this modification is used the pipe 15 will be connected to the outlet end of the ozonator 8. Gas coming through pipe 15 will go into the gas space at the bottom of the tank, and from there it willpass through the felt pad 12, which will finely divide it and allow-it to come into direct intimate contact with the contents of tank 11 in a finely divided state; all of which will be better understood from the description following under Operation.

Referring to Fig. 5, showing diagrammatically suitable apparatus for carrying out the process by the use of oxygen produced by electrolysis of the pulp water: 17 repre-.

sents a metallic agitator tank provided with suitable agitating means, such for example as the impeller 18, whose propeller axis is preferably inclined from the vertical to cause a better circulation and more uniform flow of the pulp around the periphery of the tank.

The metallic tank 17 is utilized as an anode, and the concentrically positioned metallic tube 19 forms the cathode of an electric couple connected respectively to the proper terminals of a suitable source of current for producingelectroylsis of the pulp water. A suitable diaphragm, such as 20, surrounds the cathode 19, and as shown In the present embodiment represents a concentric, unglazed, porcelain pipe. When the ore pulp is placed in the tank and a suitable source of current passed through the couple comprising the anode 17 and the cathode 19, nascent. oxygen will be liberated and intimately mixed with theagitated pulp, while the hydrogen liberated by the cathode will pass out through the upper-end of they diaphragm or tube 20 out'of substantial contact with the pulp. Of course it is to be understood that this diagrammatic showing is merely hyvway of illustration and many modifications may be made in the apparatus here shown to produce the results desired to be obtained byv this embodiment of the invention.

Operation First the embodiment of the invention relating to the use of a gas containing oxygen more active than in air, and more specifically to the use of ozone, as applied in the present preferred embodiment, will be described by way of example; then the use of oxygen, and more specifically oxygen produced by electrolysis of the pulp water, will be briefly described, in general, as another example of the conditioning treatment with a gas containing oxygen more active than in air;- and finally the use of air will be briefily described as illustrative of the use of a gas containing oxygen not more active than in air.

The ore to be treated is crushed. in any suitable manner, such for example as by grinding, either while dry or moist, and is.

passed into the tank 1 where it is preferably diluted with water. I The agitator 2 is .then put into operation and the ozonator 8 is turned on. Air passing through the ozonator is ozonized and passes through the pipe 7 and through the connecting passages in the shaft 3 and paddle blades 2, from where it is discharged into the agitated mix or pulp,

and is there brought into intimate direct contact with the particles of ore in the presence of moisture. The passage of the air through the ozonator 8 and the introduction of the gas resulting is brought about by the suction action of the agitator 2. After such treatment for a suitable length of time, the pulp is passed through pipe 9, whose valve 10 is now opened. and the pulp thus treated is passed into suitableapparatus for completing the separation. For example, if

the separationis desired to be carried out by means of flotation, as illustrated in Fig. 1, the pipe 9 will be connected to the flotation apparatus and after the frothing agent has been added and the pulp agitated to produce the froth in the usual manner, the concentrates presentin the various froths will be taken from the flotation machine in a manner well understood by those skilled in .the art.

In place'of the conditioning tank 1, the modification .shown in Fig. 4 may be employed in the above operation; in which case the pipe 15 would be connected to the ozonator and the tank 11 connected to the separation apparatus by means of the pipe 9, and the procedure carried out as above.

By way of illustration, the following example is given illustrating the adaptation of the present invention to the treatment of Pecos ore for the recovery particularl of copper, leadand zinc, and by means 0 flotation and using ozone as the treating gas A 2,000 gram sample of ore was round wet in an iron ball mill to a practical 65 mesh. This pulp was introduced into the conditioning mixer, such as 1, and the dilution was brought up to 4 to 1 by the addition of water. The mixer 2 was then put into operation at such a speed that constant bubbling was noted at the surface of the ore pulp due to the .ozonized air sucked into the pulp and distributed through the mixing blades. The volume of the ozonized air used was about the same as the volume of air usually required in carrying out the ordinary flotation process. Theamount of ozone introduced to the pulp in this manner was about of conditioning for maximum separation of copper from zinc was found to be about two hours. This is equivalent to about 0.1 lb. of

ozone per ton of ore. During this conditioning treatment, the pulp was maintained at about 60 F. At the end of this conditioning period the valve 10 was opened and the flotation of the various froths proceeded with in the regular way. I I

It was found from the above that the conditioning time was materiallyreducedinobtaining the best separation of copper from zinc. To obtain results substantially equivalent to the above under the same general operating conditions, but with the use of aeration. with ordinary air instead of ozonized air, a period of seven hours was required for conditioning of the pulp. In addition to this, it was found that much sharper separation was possible between lead and zinc, and also between zinc and iron. It was also found that after such 50 milligrams of ozone per hour, and the time conditioning the copper minerals could be thanin air, such for example as ozonized air, the differentiation of the various mineral elements contained in the ore is made much more tact with the effective. Thatis, when it is desired to separate zinc in the flotation process, by the use of this invention,'the zinc froth contains less of the other mineral elements than is possible by the usual flotation method, i. e. the zinc in the zinc froth is much more concentrated.

It is believed that the very marked bene ficial and economical results obtained, re-' sulting from effecting an alteration of the flotation properties of said particles, is caused by selective oxidation of these particles.

For this reason, or for other reasons not.

' general is carried out in a manner quite similar to that given in the above example, ex

cept that the ore pulp is placed in the tank 17 of Fig. 5, inst-ead of in tank 1 of Fig. 3, and the anode 17 and the cathode 19 are suitably connected to a proper source of electric current, the pulp mass being agitated, such for example as by means of the impeller 18. The oxygen liberated from the positive pole of the couple 17-19 and during the agitation of the mass comes into intimate contact with the mineral particles, thereby effooting the results as above described; while the hydrogen liberated by the cathode is restrained within the concentric diaphragm tube 20 and is thereby conducted out of the pulp without coming into substantial conpulp. It is believed that in addition to the generation of oxygen directly on the anode 17, that an electric charge is created on certain of the metallic or mineral particles, thereby liberating oxygen on the surface of said particlesdirectly in contact therewith.

While it is highly desirable andmore efiective to carry out the invention by the useof a conditioning as containing oxygen more active than in air, such for example as illustrated specifically herein by ozone and oxygen, nevertheless it has been found that satisfactory'results can be obtained by the use of a gas containing oxygen not more active than in air, such for example as by the use of air; the noticeable difference in time of treatment necessary being the chief difierence in the use of these various treating gases. Where it is desired to utilize air as a condiin treating crude concentrates, i. e. ore connseegeaa tioning gas, the apparatus shown in Fig. 5 may be satisfactorily employed and the method carried out in a manner similar to the example above given, except that a suitable supply of air under pressure is supplied through pipe 15, instead of supplying ozonized air as in the example above given. ternatively, the'apparatus illustrated in 3 may be employed by substituting for the ozonator. 8 a suitable air um all of which will be well understood y t ose skilled inthe art after understanding my invention.

It is to be understood that regardless of the particular oxygen-containing s em-' ployed for carrying out the invention, the general method of procedure and the results obtained are substantially identical; the chief difierence being in the periodof conditioning treatment necessary for each respective gas employed as a conditionin agent. A variation in treatment period 0 the respective gases, air and ozone has been hereinbefore pointed out in general; and it will be readily appreciated by those skilled in the art that the proper time of treatment for any specific 'ore with any specific as may be readily determined experimenta y after understanding my invention.

It may be desirable to utilize this process taining a plurality of floatable minerals, as well as t'rudeore. In which event, if the crude ore has been originally treated such as by oil flotation (either by mean's of this process or by other known processes) to produce the crude concentrates, the oil used in such prior processes'is removed from the ore particles by any suitable means, such for example as by washing, and this invention may then be practiced on the crude concentrates in a manner similar to that hereinbefore described. It is therefore to be understood that the term ore as used herein is intended as. a generic expression covering crude c oncen-' trates as well as crude ores. The important. thing to be borne in mind is that the ore to be treated must be such-that it can be intinately and directly subjected to conditioning treatment by the conditioning agent, such for example as ozone.

Of course, it will be obvious to those skilled in-the art that the conditioning treatment, forming a substantial part of this invention, is not-solely limited to its use in connection with froth flotation. as described, such for example as oil flotation; but due to the selectivemanner in which the mineral constituents of the ore are affected, the conditioning treatment of ore as herein set forth will be benefic';al in connection with other separation For example, ore so conditioned may be treated for separation on a concentra table or in any other suitable manner; a of which will be well understood by those skilled closed but not claimed herein, forms the subject matter of my copending application Ser.

No. 286,856, filed June 20, 1928, divided herefrom. In the claims the expression at a low 7 temperature is meant to include ordinary atmospheric temperature, e. g. 60 F. and temperatures below 400 C. or a red heat.

Having thus described my invention with particularity with reference to a preferred method of carrying out thesame and in connection with suitable apparatus for carrying out the same, and having referred to some of the possible modifications thereof, it will be obvious to those skilled in the art, after understandin g my invention, that other changes and modifications may be made therein without departing from the spirit and scope of my invention, and I aim in the appended claims to cover such changes and modifications as are within the scope of the invention. a

What I claim as new and desire to secure by Letters Patent is:

1. A method of ore separation which comprises bringing a gas containingfree oxygen in the presence of moisture into contact with the ore containing normally floatable cons'tituents, and thereby changing the surface of certain particles but not others normally fioatable, to a degree sufiicient to effect their flotation properties and subsequently separating the unaltered constituents from the altered normally floatable constituents.

2. A method of ore separation by flotation which comprises bringing agas containing free oxygen in the presence 0 moisture into contact with the ore containing normally floatable constituents, changing the surface of certain particles but not others normally floatable, to a degree suflicient to effect their flotation properties and subsequently adding a frothing agent and separating said ore by froth flotation.

3. A step in the method of ore separation by flotation, which consistsin making more effective the selective differentiation of various constituent elements thereof by agitating particles of the crushed orecontaining a plurality of normally fioatable constituents and bringing the crushed ore into intimate contact with a gas containing free oxygen and in the presence of moisture and during the agitation of the crushed ore and maintaining such intimate contact with said gas as to alter the I the respective oatable constituents.

froths of more effective selective differentiae 'tion, whereby the resulting frothsare sharply defined w.th respect to their respective individual contents.

4. Method of ore separation by froth flotation, which consists in making more effective the differentiation of various constituent elements thereof by forceful aeration of the crushed ore containing normally floatable constituents with a gas containing free oxygen and in the presence of moisture and before the addition of a frothing agent, adding the frothing agent to the mix so treated,- agitating the resultant mix, and successively forming and removing froths of the various constituents of the ore.

5. A step in the method of ore separation by oil flotation, which consists in makin more effective the selective differentiation 0 the various constituent elements thereof by bringing particles of the crushed ore containing a plurality of normally floatable constituents into intimate contact with a gas containing oxygen more active than in air and in the presence of moisture and during the agitation of the crushed ore, and subsequently addin oil during agitation to the oreso treated, ormin successive froths containing 6. A step-in the method of ore separation by oil flotation, which consists in making more effective the selective differentiation of the various constituent elements thereo'fby bringing particles of the crushed ore containing a plurality of normally floatable constituents into intimate contact with a gas containing oxygen more active than in air and in the presence of moisture and during the agitation of the crushed ore, and subsequently addin oil during agitation to the ore so treated, orming successive froths containing the respective floatable constituents, whereby the resulting froths are sharply defined with respect to their respective individual contents, and fractionally separating the respective minerals by froth flotation, the flotation froth of each respective mineral so separated being'substantially free from-other minerals.

7. Method of ore separation by froth flotation, which consists in making more'eflective the differentiation of various constituent elements thereof by bringing particles of the crushed ore containing a plurality of normally floatable constituents into intimate contact with a gas containing oxygen more active than in air in the presence of moisture and before the addition'of a frothing agent, addin the frothing1 agent to the mix so treate agitating t e resultant mix, and

forming successive froths containing the re spective floatable constituents.

8. Method of ore separation by froth flotation, which consists 1n ma more effective the-diflerentiation of various constituent elements thereof bybringing particles of the crushed ore containing a plurality of normally floatable constituents into intimate contact with oxy n in the presence of moisture before the addition of a frothing agent, addin the frothin agent to the mix so treate agitating t e resultant mix and forming succemive froths containing the reive floatable constituents.

9. A method of ore separation which comprises treating 'with a gas containin oxygen a wetted ore ulp containing lea copper and zinc sulph1des, continuing the treatment with said gas until the particles containing lead, cop r and zinc sulphides possess changed otation roperties with respect to oneanother, com ining the so-treated ore with a frothing agent, subjecting the combination of frothing agent and ore to aeration and separating by flotation the lead, zinc and co per sulfides.

10. A method of ore separation which comprises treating with a gas containin oxygen a wetted ore ulp containing lea copper and zinc sulfi es, continuing the treatment with said gas until a coating is formed on metallic particles suflicient to change their flotation properties, combining with the sotreated ore -a frothing agent, introducing air into the combination of frothing agent and treated ore and separating-by flotation a lead concentrate high in lead, and containing some zinc and copper, and a zinc concentrate high in zinc-and containing some copper and lead.

In testimony whereof I have signed my name to this specification.

ARTHUR J. WEINIG.

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