US1277750A - Flotation process and apparatus. - Google Patents

Description

1. A. PEARCE.

FLOTATION PROCESS AND APPARATUS.

APPLICATION H LED MAY 29, I911- 1,277,750. Patented Sept. 3,1918.

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- FLOTATION PROCESS AND APPARATUS.

APPLICATION FILED MAY 29, I911.

IIII- n [p l IL k0 O Patented Sept. 3, 1918.

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JACKSON A. PEARCE, OF'IDAHO SPRINGS, COLORADO.

FLOTATION PROCESS AND APPARATUS.

. Specification of Letters Patent.

Patented sent. 3, 1918.

Continuation of application Serial No. 147,699, filed February 9, 1917. This application filed May 29, 1917.

Serial No. 171,649.

To all whom it may concern:

Be it known that I, JA'oKsoN A. PEARCE, citizen of the United States, residing at Idaho Springs, Clear Creek county, and State of Colorado, have invented certain new and useful Improvements in Flotation Processes and Apparatus; and I do declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to the characters of' reference marked thereon, which form a part of this specification.

My invention relates to a process and apparatus for the separation of mineral values on the flotation principle, oil or other substance being mingled with the pulp and acting in combination with air bubblesto cause the mineral values to rise to the top whereby they may be skimmed off as a sort of froth.

In my improvement I employ a series of chambers each of which is dlvided by a partition into a receiving and a separating compartment, the bottom of the receiving compartment having an opening to allow the pulp to pass therethrough, after which it is acted on by an impeller which for ces it through an opening in communication with the separating compartment, into the bottom of the latter compartment, the im-,

peller serving to maintain the receiving compartment practically empty -while the separating compartment is kept full, provision being made to allow the pulp to overflow from the separating compartment into an adjacent receiving compartment, thus preventing as far as possible any gangue ,Or comparatively barren pulp from passing with the mineral froth into the launder which receives said froth.

By virtue of the fact that the receiving compartment is kept practically empty, the pulp has a considerable fall both as it overflows into the receiving compartment from an adjacent separating compartment, and

5e impeller below the bottom ofthe receiving also when originally fed into the receiving compartment. During this fall from the top to the bottom of the practically empty receiving compartment, air is entrained or caught by the pulp and carried downwardly therewith. Furthermore the rotation of the compartment, produces suction whereby air is further mingled with the pulp as it is forced into the bottom of the separating Figure 1 is a vertical section taken through the apparatus on the line l1,

Fig. 2 is "a top plan view in detail of the impeller shown on a larger scalethanin Figs. 1 and 3.

Fig. 3 is a top plan View of the apparatus.

Fig. 4 is a side elevation of the impeller shown on the same scale as Fig.2.

The same reference characters indicate the same parts in all the views.

Letthe numeral 5 designate a casing considered in its entirety, and provided with a number of partitions 6 separating the easing into a number of chambers 7 each of which is divided by a partition. 8 into receiving and separating compartments respectively, designated 9 and 10, each pair of which may for convenience be designated a unit. The receiving compartment has a bottom 12 which i supported somewhat above the bottom 13 of the casing, leaving a space 14 between the parts 12 and 13. This space is in communication by-an opening 15 with the bottom of compartment 10, the latter being provided with an inclined wall 16, which extends downwardly from the top of the compartment and joins the horizontal bottom 13 of the casing as shown at 17.

In the space 14 between the bottoms 12 and 13 is located an impeller 18 which is rotated at any desired speed through the medium of a vertically disposed shaft 19 which is journaled in across piece 20 supported above the compartment 9. This shaftcompartment empty. It will be understood from what has ,already been explained that by rotating the impeller 18 at the desired speed, the pulp may be removed from the receiving compartment as aforesaid into the separating compartment, practically as fast as it enters the receiving compartment, thus maintaining a part of the opening 22 in the bottom 12 sufficiently free to permit a relatively large quantity of air to be sucked therethrough with the pulp as the latter is drawn downwardly byreason of suction developed by the centrifugally acting impeller.

Within the separating compartment, I arrange a number of deflectors or blades which have a tendency to cause the gangue as it passes upwardly in the receiving compartment, to move toward a short trough 2 1 which is sunk into the partitions 6 and 8 at their intersection, the bottom of the trough being on a proper level to receive the overflow from any separating compartment and deliver it to an adjacent receiving compartment as best. illustrated in Fig. 3. These blades constitute baffles and are respectively designated by the reference characters 23 and 23 (see Fig. 1.) If it is desired to. deliver the overflow to a remote receiving compartment, an additional trough 25 may be employed which extends above the top of an adjacent receiving compartment and directs the overflow into a remote receiving compartment as ust explained.

. In this way oneor more recelvinggcompartments may be cut out, so to spea and the overflowfrom any separating compartment delivered to any desired recelving compartment.

As shown in the drawing, two launders 26 and 27 are supported adjacent the casing 5 on the froth discharge side, the froth 28 being removed from the top of the receivink compartment by a rotary skimmer 29 of suitable construction. In case the froth is dirt or not sufiiciently clean it may be desire to return it for re-treatment and in this event a bridge 30 may be placed ontop of or over the launder 26, the same being of suflicient width to direct the froth into the launder 27. Thisbridge is removable and "may be employed in connection with any separating compartment, and should be used if it appears that the froth as it leaves any separating compartment is not suffi-v ciently clean for commercial purposes. a

This application is a continuation of my prior application, Serial #1 17 ,699, filed Februar 9,1917. The apparatus as illustrated dlscloses a battery or set of chambers 7 each divided by partitions 8 into receiving and separating compartments. From this it will be understood that the overflow pulp may be subjected to any desired numer of treatments since as it leaves theffirst separatmg compartment, it may pass to the second receivin compartment and so on whereby it is subjected to any desired number of treatments, the construction being such that the pulp is practically completely impoverished of the originally contained mineral values. 7

As illustrated in the drawing, the pulp, which it may be assumed contains a suitable proportion of oil, is fed as shown at 31 into the receiving compartment 9 of the first chamber and passes thence into the separating compartment 10 of the same chamber, from which it overflows into the second receiving compartment 9 and so on. Or, if the additional trough 25 is employed, the overflow may be carried to a remote receiving compartment as heretofore explained.

From the foregoing description it is believed the invention will be readily understood. The falling of the pulp as it is orig inally fed into the first receiving compartment 9, downwardly into the bottom of said compartment, naturally entrains as heretofore indicated, considerable air and as it is sucked through the opening 22 into the space below by the action of the impeller, a relatively large quantity of air is mingled therewith in the form of bubbles and unites with the oil to gather the mineral values on the well-known flotation principle whereby they are caused to rise to the top of the separating compartment and removed in the form of froth in a manner that will be well understood. In this application Idesire to emphasize the feature whereby the pulp is delivered into a substantially empty receiving compartment while the adjacent separating compartment in communication therewith at the bottom, is kept full by the centrifugal action of the impeller or any other desired form of pumping apparatus, thus greatly facilitating the mingling with the pulp of the necessary air and contributing in an important degree to the eflective separation of the mineral values from the pulp in the receiving compartment and to flexibility of operation.

Attention is called to the fact that the material to be treated is fed into the separating compartment at a lower level than the discharge from the separating compartment. In other words, in my improvement the tailings as well as the mineralized froth are discharged from the top of the separating compartment. By having the feed into the separating compartment lower than the discharge from said compartment, there is a great advantage due to the fact that by this arrangement there. is always a considerable fall between the top of the separating compartment and the point of feed to said compartment, thus making it unnecessary to automatically accomplished due to the fall from the pointof discharge to the point of eed, speaking with reference to the separating compartment. v

I wish to emphasize the importance of the overflow discharge of the tailings at the top of the pulp in the separating or flotation compartment at approximately the same level as the froth overflow. 1 If the tailings the outlet and the machine, consequently a valve and careful regulation of the valve are necessary.

Furthermore, in any machine with a discharge below the surface there is a tendency for the coarser particles to discharge in preference to the finer particles with the consequent accumulation of colloids above the discharge, including colloidal matter. In my machine, the discharge being at the top of the pulp, the tendency is for the colloids to discharge in preference to the coarser particles with a consequent accumulation of the coarser or granular particles within the machine, .thus raising the percentage of granular material. This is a distinct advantage in flotation. In the course of a short time this percentage becomes constant,

the granular and colloidal material over-' flowing in the same proportion as in the feed.

Besides, the retention of the coarse ma terial in the rising column up to the gangue overflow, subjects the coarse material, in a relatively quiet region, to the bubbles com- '-ing from the agitation compartment and enhances the likelihood of values therein be- ,ing caught and carried into the froth.

aving thus described my invention what I claim is: 1. The herein described flotation process including aerating the pulp, overflowing the froth, maintaining the tailings in Suspen-- sion by an upward circulation of the pulp in a flotation compartment, and overflowing the tailings wholly from said compartment at a substantial distance above the inlet and in proximity to the level of the overflow of the froth but separate therefrom.

2. The herein described flotation process consisting in feeding pulp into a chamber above the bottom of the latter, aerating and forcing it from the bottom thereof into the bottom of another chamber to keep the first chamber substantially empty and the sec- 0nd chamber full at the desired height above the bottom of the first chamber, overflowing the froth, .maintaining the tailings in suspensionby the upward circulation of the pulp in the chamber and providing for their overflow wholly at a substantial distance above the inlet, in proximity to the level of the froth overflow and separate therefrom. 3. A flotation separating unit comprising an agitation compartment and a flotation compartment having a froth overflow, the said compartments communicating at the the bottom, the flotation compartment being relatively deep and having a tailings dis charge away from the unit, at a substantial distance above .the inlet and in proximity to the level of the froth overflow, but separate therefrom, the unit being otherwise closed against the discharge of the tailings.

A flotation separating unit comprising an agitation compartment and a flotation compartment communicating at the bottom, the flotation compartment being relatively deep, provided with a froth overflow and having a tailings discharge away from the unit, at a substantial distance above the inlet and in proximity to the level of the froth overflow, but separate therefrom, the unit being otherwise closed against the discharge of the tailings, means for feeding the pulp into the agitation compartment above the bottom, means for forcing the pulp from the bottom of the agitation compartment into the bottom of the flotation compartment, said last named means being adapted to be operated to maintain the agitation compartment substantially empty and the flotation compartment full, and means for removing the froth from the upper part of the flotation compartment.

5. Flotation apparatus comprising a plurality of flotation separating units each composed of an agitation compartment and a flotation compartment, the flotation compartment of each unit except the last being arranged to have a tailings overflow from its own unit into the agitation compartment of another unit, such overflow being at a substantial distance above the inlet to the flotation compartment and approximately at the level but separate from the froth overflow, the delivery to the agitation compartments being spaced a considerable distance above the normal pulp levels therein to provide a substantial drop through air, the agitation and flotation compartments of each unit being in communication at the the pulp from the bottom of the agitation compartment into the bottom of the flotation compartment.

6. Flotation apparatus including a cham ber divided into anagitation compartment and a relatively deep separating compartment in communication at the bottom with the agitation compartment, provided with a froth overflow, and having a'gangue overflow at a substantial distance above the inlet and in proximity to the level of the froth overflow, the chamber or unit being otherwise closed against the discharge of gangue.

7. Flotation apparatus including a chamberdivided into an agitation compartment and a relatively deep separating compart ment in communication at the bottom with the agitation compartment, provided With a froth overflow and having a gangue overflow at a substantial distance above the inlet and in proximity to the level of the froth overflow, the chamber or unit being'other- Wise closed against the discharge of gangue, means for feeding the pulp to the agitating compartment above the bottom, means for forcing the pulp from the bottom of the agitating compartment into the bottom of the separating v compartment,. said last named means bein adapted to be operated to maintain the agltating compartment substantially empty and the separating com-' partment full, and means for removing the froth from the top of the pulp in the separating compartment.

In testimony whereof I afiix my signature.

JACKSON A. PEARCE.

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