US 1886979 A
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Description (OCR text may contain errors)
Nov. 8, 1932.
J. P. RUTHfJR 1,886,979
FLOTATION METHOD Filed Jan. 2e. 1931 4f ff, 4, /f /f y 1: f i 9 fa f7 f4 0 0 77 I Y l C -"1 y "n l k/ gmc/vwo@ l A /Me 2 umy.
@ttor/mag Patented Nov. 8, 1932 UNITED STATES PATENT OFFICE i .Tosnirr r. RUTH, m., or nENvEn, i y
mach appnann mea :anaal-y 26,1931. serial ,110. 511,448.
This invention relates to improvements in methods for operating "flotation machines of the type (employed in separating mineral values from angue.
In themimng of metals it is now common practice to employ flotation machines for the selective separation of the minerals from the gangue. It has been found from extensive experiments that flotation machines operate at their highest eiiciency only when they operate at `maximum capacity and' with the present forms of flotation machines this is a condition that prevails only in mines where the ore supply is equal to or greater than the capacityof the machines employed.
A flotation machine is composed of a plu- .rality of units or cells, each'having a receiving conduit and a frothing chamber, an impe ler isilocated in a passageway that connects the receiving conduit and the frothing chamber and this transfers the pulp from the former to the latter and mixes it with air.
The froth overflows into a froth launder and the tailings from each cell, except the last, is delivered to the receiving conduit of the next cell in the series and the tailings from the last cell is conducted to a' vtailings dump. The
ulp is fed into .the receiving conduit of the Erst cell orunit in the series and therefore passes succeively through the several cells of which the machine is composed. Since some of the values are removed in each cell,
it is evident that the richness 4of the pulp decreases as the pulp progresses through the In designing flotation machines for mines, it is customary toprovide for sutlicient capacity to take care of the naximum output of the mine and as `a result the machines frequently operate on a suppl that is considerably below the capacity or which the machine -wasdesigned and therefore the eiliciency at which the machine operates is below maximum which means that there is a loss Vof mineral valu that could have been `saved if the supply of pulp supplied were I have found that if a portion of the tailings, ,of being transferred to .the dump, is returned to the receiving conduit of the first cell of the machine, it is possible to operate the machine at maximum capacity at all times, regardless ofthe fact that the supply of pulp is less than the ca acity of the machine. It is obvious that i the maA` chine was operatin at full capacity in the ordinary way and the supply of pulp cut off and all of the tailings returned to the intake conduit of the first cell the quantity of ulp circulatingthrough he machine would) remain the same exce ltfor the loss due to the froth overflow. If esh pulp to the extent of one-half of the capacity is supplied to the intake conduit of the firstcell and one-half of the tailings returned, the machine will be operating at maximum capacity and consequently at maximumeiliciency.
In order to more clearly define the method described above an apparatus by which it can be carried out will now be described land for this purpose reference will be had to the ae. companying drawing in which:
Fig. 1 is a top-plan view of an assemblyof cells showinr the launder by means of which a portion of the tailings are returned tothe receiving conduit of the first cell;
Fig. 2 is aside elevation of the cell assembly and Fig. 3 is a transverse section through one of the cells.
The assembly illustrated comprises six cells 4 arranged one above the other as shown in Fig. 2, each of the cells has a receiving conduit 5 and a frothing chamber 6. Line 7 in Fig. 3 indicates the ulp level and the pulp overflow is indicate by reference number 8 while the froth overflow is designated by numeral 9. A spout 10 is located underneath each pulp overflow and is inclined so as to carry the pulp to the receiving conduit of the next higher cell. A froth launder 11 extends underneath all of the froth overflows. The spout 10 from the last cell in the serie-s is connected with a launder 13 that extends to the receiving conduit of the lowermost cell in the series. In order to vary the proportion of the total of the tailings that are returned, a plate 14 is secured the inside of the spout 10 by a hinge, the 'nge is located at the lower edge of the plate 14 and its position is controlled by a screw 15. If plate 14 is moved so as to c'ontact with both/sides of spout 10, all of the tailings will be returned, if it is moved up against the side to 5 which it is hinged, none of the tailings will be returned andany proportions between these extremes can be returned by moving plate 14 to the corresponding intermediate position. c
1 The cells are each provided with animpeller 16 that is secured to the lower end of the impeller shaft 17.
The apparatus described is merely illustray tive and applicant does notwant'the same to beconsidered as in any way limiting the scope of his claims.
From the above it is evident that by returning a suflicient amount of tailin s and mixing them with the original pulp, t e ma- 20 chine can always be operated at maximum capacity and eiiciency. It is also evident that by returning a portion of the tailings and having them pass through the machine, they will be subjected to a second operation that will remove an mineral values that would otherwise have en lost.
I consider that the discovery that flotation machines operate at greatest efliciency when operating at` ull load capacity and that this condition can always be obtained regardless of the actual amount of pulp available by the simple expedient of returning a portion of the tailings to the intake conduit of the first cell constitutes my invention and it is of great practical importance in this art.
Having described the invention what is Y claimed as new is: l
1. The method of operating a series connected group of flotation machines so as to obtain the maximum efficiency when the pulp available is less than that required for the capacity corresponding to maximum eiiciency which consists in returning tailings from the last cell of the seriesto the intake conduit '35 of the first cell in such amount that the returned tailings and the original pulp supply v will equal the amount necessary for 'maximum eiiciency.
2. The inethod of operating a flotation machine, having an intake conduit and a tailings discharge, at maximum eliiciency when the pulp available is less than that which is required for maximum eiiciency which consists in returning so much of the tailings. to 55 the intake conduit that the returned tailings and the supply of untreated pulp together produce a load that corresponds to that which is required for maximum efliciency.
In testimony whereof I aix m si ature.
JOSEPH P. R T JB.
DISCLAIMER .-,Jeseph P. Ruth, Jr., Denver, Colo. FLo'rlurIorv MTHOD.
November 8, 1932. Disclaimer filed August 23, 15935, by the patentee.
Patent to the method therein defined only when made effective through certain specifically characterized apparatus of that vtypeillustrated in said Letters- Patent, t0 Wit: i A
Flotation machines wherein the tailings stantial distanceabove the pulp feed inlet to said cell unit the froth discharge from Saidv cell unit, and operative capacity sucient tomaintain thelv stantially empty. v
[O cial Gazette September 17, 1935.]-
discharge from each-cell unit is a'subandseparate from and below feedcompartment of itscell unit sub- Patent dated Hereby enters this disclaimer tovlimt the Iscope of claims Land 2 of said Letters wherein the impeller element has an