US1243814A

US1243814A - Apparatus for separating or concentrating ores.

Info

Publication number: US1243814A
Application number: US4344415A
Authority: US
Inventors: David Cole
Original assignee: Individual
Current assignee: Individual
Priority date: 1915-08-03
Filing date: 1915-08-03
Publication date: 1917-10-23
Anticipated expiration: 1934-10-23

Description

D. COLE. APPARATUS FOR SEFARATING 0R CONCENTRAUNG ORES.

'APPucmoN FILED MIG-3. ms. 1,243,814. Patented 0m. 23,1917.

4 suzns snzn a.

A wucu l'oz D. COLE. v APPARATUS FOR SEPARATING 0R concemnmufeonas.

- APHICATIQN mm Aucha. 1915. 1,243,814. Patented Oct. 23,1917

o. COLE. APPARATUS FOR SEPABATING 0R CDNCENTRAUNG ORES.

APPLICATOH FILED AUG-3,1915% 1,243,814. Patented Oct. 23, H117.

- Q SHEETS 'BHEET 3 wihwoo I u. COLE. APPARATUS FOR SEPARATING 0R CONCENTRATING (IRES,

APPLICATION FILED AIIGJ. I9I5- Patented Oct. 23, I917.

4 SHEETS-SHEET 4.

wihweoo nuvzhIoz DAVID COLE, OF MORENCI', ARIZONA.

APPARATUS FOR SEPARATING OB- CONGENTRATXNG BEES,

Specification of Letters Pa tent.

lateniteil that. $32 K915i.

Application filed August 8, 19115.v Serial No. 43.4%.

To all whom it may concern:

Be it known that I, DAVID Gone, a citizen of the United States, residing at Morenci, in the, county of Greenlee and State of Arizona, have invented or discovered certain new and useful. Improvements in Apparatus for Separating or Concentrating Ores, of which the following is a specification, reference being had therein to the accompanying drawings.

This im'cntion relates to the separation and concentration of ores and minerals by the flotation method wherein that part of the valuable portion which has been pulvcrized too fine to be readily concentrated by gravity separation, in water, is caused to be attached to bubble films and is carried over the top of the vessel or container in the froth which accumulates upon the sun face of the Water. and pulp when the mass is properly aerated: and wherein that part of the valuable portion not mad fine enough to be lifted by the rising; hubhlesaud he carried over by the froth as before mentioned, will readily fall. and may then he successfully and easily separated by the usual gravity system of concentration.

In the application of flotation methods two distinct divisions are recognized in the older one of which violent agitation is ereatod hy the rapid revolution oi sl'irrors or impellers, which has the eil'cct of drawing air in o the pulp and mixing it intimately with t a mass. This method is ex ensive to operate because it-uses power ine ciently.

In the other division, which is known as the pneumatic method, air is introduced into the pulp through filtering mediums forming the flat, horizontal, or inclined bottoms of the tanks. .and the process is embarrassed by the settling upon. the porous mediums of sands and mineral grains too coarse to hc held in suspension or moved far by the rising'huhhles of air. Because it is essential that the air be in very smallhuhbles in order to obtain cllicicnt and satisfactory results in the separation of the minerals, and since small huhbles have little lifting power and do not cause violent agitation, it has been found impossible in practical work entirely to prereut the clogging of the air filtering mediums except when all grains are of very small size. Forcing air under relatively higl'i pressure. and in large volume through feed and easily kept in sr... divisions of the present pra limited so far as sizes of or ore are shines or exp 'er 03: these inetho. no" of rele ti lyre issi'nedsnater In the pros the separ sary 1 ca ed. fill far soon n min ral crystals that the classes.

(iorthepu'rg; sized grains within the range oi iiotathim treatment as aluiv'e outlined) :iuwilres a much increased expenditure for crushing that wouldv not otherwise be necessary.

In order to simplify the operations and 7 reduce the amount of expenditure by elimi hating, to a. maximlmr-entent, the necessity of pulverizing the ore and minerals beyond the economical point previously explained, the cllici'ent praoticejof the flotation method of sepz'irating minerals in olves, over the present state of the art, the successful and practical working out of the following desidcrata:

First. Providing a grated air admission filter or diaphragm, ellleieut for aerating; purposes and affording ample passageways for the falling pulp and -r s "elm cities will be new and no ou' lcs wizl be taken through the grates with the rciections.

Second. Providing an air admission medium having the functions of the t item and .whose air emitting surface is so arranged and disposed that material falling upon it will not be retained to clog the filtering surface or impede the free flow of air.

Third. Providing an air admission me dium having the functions of the first and second items and which will allow the easy passage of air outwardly into the pulp and water under treatment, but wilt allow the passage inwardly, under hydrostatic pressure, of clear water only, thus preventing the blinding of the air emission filter from. the deposition of solid matter on the inside of same.

Fourth. Providing a frothing machine of large capacity utilizing the filtering system mentioned in the foregoing items, into which it will be possible to put the product made by the grinding machine, at relatively coarse sizes, directly and concurrently, without the introduction of intermediate screening, sizing, hydraulic or other classification, to the end that the mineral values already fine enough for removal by flotation may be taken out/first and as fast as produced by the grinding operation, thus making sure that the slimed minerals will be thoroughly combed out of the pulp being treated before it is subjected to the gravity treatment which follows for the purpose of collecting and separating the coarser grains of liberated mineral too coarse to be amenable to the frothing method of separation, Fifth. Providing a frothing sizer of large capacity in whichthe stream of pulp undergoing flotation treatme will gravitate longitudinally through a succession of aerating compartments in such a Way that the heaviest and largest sand particles which fall fastest will. be lodged in the first hoppe'red subdivision of the tank, and successively smaller particles be deposited in the hoppers arranged successively farther from the'point of entry for the pulp under treatment.

Sixth. Providing a frothing machine of iargo capacity which will, concurrently with the frothing operation, separate the portion which falls, into two or more classifications or sizes, so that one or more of the coarser sizes still containing grains of unlibcrated or included mineral may be returned to the grinding machine to be further pulverized, the last mentioned return product constituting a closed circuit with the grimling machine.

in another application for Letters Patent filed by me August 1, 1715, Sm: No. 43,442. l have shown anddoscribmlseveral forms of apparatus capable, in rrrtain ways. of Fulfilling all of the foregoing conditions, and the present invention has for its general object to provirh-v another form of apparatusof lhis character which is further improved with respect to lhoso features.

The foregoing and olhcr objectsv f the inlrollrd.

vent'ion, together with means whereby the same may be carried into effect, will best be understood from the following description of one ,form or embodiment thereof illustrated in the accompanying drawings; It will be understood, however, that the particular construction described and shown has been chosen for illustrative purposes merely, and that'the invention, as defined by the claims hereunto appended, may bev cmbodied. in other forms without departing from the spirit and scope thereof.

In said drawings:

Figure 1 is, a diagrammatic plan view of an apparatus constructed and arranged. in accordance with the invention. v

Fig. 2 is'an enlarged longitudinal vartical sectional. view of the frothing classifier or sizer in Fig. 1.

Fig. 3'is a transverse section on the line 3 3 of Fig. 2.

Fig. 4 is a plan view, partly in section on the line 4:4 of Fig. 2, of a portion of the classifier or Sizer.

Fig. 5 is a diagrammatic view of a portion ofthe classifier tank, illustrating the arrangement of the air tubes and the emission of air therefrom.

Fig. 6 is a plan view of a portion of the air tube grating. V

Fig. 7 is an enlarged longitudinal sectional view of one of the air tubes, and

Fig. 8 is a transverse section on the line 88 of Fig. 7.

Referring to Fig. 1, 12 denotes a tube or other mill of any suitable or well known form for reducing the ore or other material to be treated. Said reduced material, containing a certain amount. of oversize incidental to the etlicient operation of the mill,

is discharged into a trough or chute 13 leading to the frothing classifier or sizer.

Said classifier or sizer comprises a tank 14 having. at one end. an inlet 15 with which said trough or chute 13 communicates, and at the opposite end an outlet 16.

'17 denotes a sliding gate arranged witnin the tank 14 adjacent the inlet 15 but spaced from the latter, said gate being vertically adjustable in guides 18 by means-of a. hand wheel 19. Thogato 17 serves to deflect downwardlv the material entering at the inlet 15. and by adjusting said gate the effective height of said inlet may be con- 20' denotes a sliding gate adjacentthe outlet 16 and adjustable inguidos 21 by means of a hand when] 22'. By adjusting ihogato 20 the effective height of the outlot, and consmpiontly the normal level of the liquid in (he tank 14-. may be controlled. 23 and 24 denote balllo plales'nrrangod adjacent the gate 90 for securing a. gentle and oven discharge ol'itho liquid from said tank over said gate into the outlet 16 and for prevcnt-, ing the discharge of froth at this point.

The bottom of the tank 14: is composed of a. longitudinal series of hopper-shaped sizing compartments or pockets Four of these compartments are shown in Fig. 2, although. the precise number may be in accord-- ance with the requirements. Cooperating with the compartment at the end of the tank 14; adjacent the inlet 15 is an elevator operating in wells 56 within the sides of the tank, said elevator comprising a belt 27 carrying buckets 26 and passing; over an. idler pulley 28 and a supporting and actuating pulley 29, as shown in Figs. 2 and The pulley 29 is mounted on a shaft 30 suit ably journaled above the tank 14 and adapted to be rotated from any suitable source of power by means of a belt pulley 31. Adjacent the pulley 29' the buckets 26 discl'iarg'e their contents into a suitable chute 32 The remaining compartments 25, or those adiacent the outlet end of the tanlnas shown, are

' provided with fluid pressure lifts or ejectors 33 adapted to discharge material accumu- .lating in said compartments into chutes 3e arranged at the top of the ank and adapted to conduct said material. to suitable concentrating tables (not shown) or elsewhere as may be desired.

The elevator 26, 27'and fluid pressure lifts 33 are merely illustrative of convenient means for discharging the material accumu lating in the compartments 2%, and while such means are preferred it is obvious that said material might be otherwise discharged as by providing said compartments with openings in their bottoms thro'uoh which the material could be with rawn into suitable chutes or other conveyingmeans beneath the tank 14. Also while in the construction shown only one of the compartments arranged to discharge its contents into the chute 32, any suitahlenumher of eompartmcntaat the inlet end of the tank may so arranged, the essential idea being that the material from one'or more of the compartments 25 at the inlet end, of the tank be dis charged separately, asinto the chute 32, from the material in the remaining con1- partments at the outlet end of the tank which are discharged into, chutes 34-.

36 denotes launders arranged to receive material overflowing; the top-of the tank 14. As herein shown two of said launders are provided, one on each side of the tank within the same. each of said launders discharging through an opening, 37 in the side of the tank midway of the length thereof, the material passing, out from said openings beingjconveypd by troughs or other means (not shown) to any desired point.

In the apparatusshown the coarse material delivered to the chute 32 is discharged therefrom upon a concentrating table 38 of any usual or well known form. The mate rial rejected by said table is returned by any suitable means, herein diagrammatically represented by a conveyor 39, elevator 40 and conveyor 4]., to the mill '12 for regrinding.

Air is admitted to the tank 14 through a series of horizontally disposed filter or air tubes shown, extend transversely of the tank and collectively constitute a tubular grating which extends substantially throughout the length of said tank so as to cover the entire horizontal cross sectional. area. thereof. at a level above the siting compartments 2 The tiibes are so constructed as to have a finely porous air emitting surface, whereby compressed air-supplied to tubes is dis charged into the tanloin a finely divided state and passes upwardly through. the liquid in the tank in the form of numerous streams of fine bubbles,

The precise construction of the tubes is susceptible of considerable yariatioin l referably, however, and as shown most Said tubes, in the construction clearly in Figs. T and 8, each of said tubes comprises a metal pip-e provided on its outer surface with a coarse thread. 42 forming a spiral channel in the wall of said pipe, in which channel is spirally wound a suitable cord or rope 43: secured at its ends, as by pine 15, to said wail. At its upper side said wall is provided with slots i6 extending from the interior of thepipe and eommuni eating with the bottom of the channel 43 which, slots may be of any suitable length and arrangement. This construction prorides. in a simple and inemuensive manner, an air tube having the desired filtering; or porous air emitting; surface since the cord. 14 when wound and secured in the manner describee'l, while constituting: a suitable til" toting! material, will. support itsol 1", requir iilfl' no binder in. order to re am e same in place on pipe, laill cord or rope is of a suitable to fit tightly, at the sides; the walls of the channel 43., preventing egressot' air otherwise than through the fabric or fibers of the cord, and is located deeply enough in the groove, within the outer edges of the threads 42, to be protected thereby against abrasion or accidental cutting; The metallic portion of the .air tube may be readily east in the form required, so that no machine work is necessary to form the chan nel 43, the cord 44 serving! to fill all nne'v'enness in the Width of said channel. so that said tubes are relatively :JI pic and inert pensive to manufacture wnleprmiding a sl'lbetantially uniform porosity from and to end.

The tubes I I6 are c osed at one end by caps 4-7 and, at their opposite ends, commimicate with and are supported by headers 48 arranged at the opposite sides of the tank and supplied with compressed air from mains 5O through branch pipes 49 severally provided with valves lil- The headers 48 I outer ends ol said-tubes due to the discharge,

are preferably of less length than the tank l4, \vherelrr the tubular grating. as a whole, is formed in sertions arranged longitudinally of said tank. said serlions eorres mluling" in length suhstantiall t' to the sizing eoinpartinients The-pores ol the tubes 35, all'orde'd by the filtering; medium or ('(Htl 44, are too small to allow solids to enter said tubes 'troin the. outside, under hydraulic pressure when the eompressed air is eut: oll. thereby preventing the internal elo 'ging ot said tubes. Haid tubes are spared l'rom one another a suitable distauee to atl'ord between them easy downward passages for the material under treatmeut into the sizing eompartments 25, while being sutl'ieientlv rlose together to provide. for the thorough aeration of the, contents of the tank. By the provision \vhorelrv the material in the eompartuients 25 is removed therefrom at a point eonsiderablv below said tubes. all violent down-- ward currents or vortiees in the vir-inity ot said tubes, tending to dranthe bubbles downwardly are avoided. and all possibility ot improper fllHt'lllHQ't ot the tiner material with the material properly deposited in the sizing: ronipartn nts L15 redueed to a mininuun. l'he air emitting surlaee allorded by the porous cord or rope -l| extends (Ultipletely about the peripheuv or rireumt'eu enee of the (-arrespoinling tube. so that all possibilitv of such aeeumulation ol' sediment as would clog the exteyior oi the tube and interfere with the. proper disobargge o'ti air therel'roui is preventml/it being obvious that. even though the entire upper surt'aees ot the. tube" were eorered hr deposits. there would still be left a t tal unobstru ted air emission surtaee equal to or greater than the entire horizontal area ol the taul\' not \\lll!Ht'lH(liH the passages between the tubes.

By reason of the. tart that the tubes 35 \vhieb extend substantially rompletelr across thefi tank and are. of subshintiallr eonstaut porosity throughouttheir length, communi eat-e. at one end only with the headers -18, there is a tendency for the air to be diseharged more rapidllytrom the. inner ends of said tubes adjaeent said headers than from the. outer or closed ends thereof. This tendency is (liagrauunatieally illustrated in Fig. 5 and is due to the fact that there is a dill'erenooin pressure between theinner and of air at intermtniiate points. In order to compensate for this, and to secure a thorough and even aeration of the eontents of the. tank. the headers 48 are arranged at opposite sides-0t the tank, as above doseribed, while. the. tubes 35 are as nearly as possible so arranged that alternate. tubes of the series eonnnunucate with. are supported 1) and' )ro'eet trotn headers at'o osite sides. as illustrated in Fig. 6. As shown in the. latter tigure eert'ain ol the tubes 35 are n'iade of less length than the others to provide spaees St \rhereb the l'iydraulic lil'ls 32) may extend upwardly through the tubular grating.

At suitable points longitudinally of the.

tank 11-; are provided vertically arranged shutters 5". (Nittltlltlg across said tank and preterubtr sparedto eorrespond with the spacing ot' the sizing -ompzntinents 35. haid shutters are provided. with slats 53 inclined ttownuarilla' in the direction of the llovv through the tank and with adjustable tlaps 5-lronueeted to operating rotls 55. The. shutters 5:1 prevent eurrents 't'roni being, setup longitiulinallv olthe tank, racing one. \\'a at. the bottom and the other the. flaps 54 acting as valves to prevent the material from lloniu in an in'iproper (liree tion. and together with the inclined slats a3. direetiug the path of the eurrent. cans-- ine it to plan uiore. or less in passir" t-hrou g'h the. shutters, whereby the ot the sizing ron| iartnn-nts hereinafter err plaiin-d nia be varied or rontrolled. Also said shutters 5; [end to direetthe upward passage ot the bubbles lroin the air tubes, musing them to remain Within that longitudinal portion of the tank in whieh they originated, so that the truth formed by said bubbles. as hereafter explained. will he rieherabove. the first eompartinent than above the succeeding ones and maybe sepa rated from the other grades it' desirm.

'lhe eoinplete operation of the apparatusv is as follows: The eoniminuted material from the mill 'li". togethe with a suitable amount of water. and with or without 4201* tain other uialeria ls or troihin g; agents snob as 'oils. :zrids and th like. the Whole forminu' what is kiln n as pulp lm ll. ;l"l}ttif EO-l into the tank H through the inlet. in, the liquid liltingsaid tank and overflowing into the outlet i Th e iumiuuted material above rel e'rred to. when the mill 12 is operated in its most ellieient and eeonomiralmannet: as heretotore tXPltiiHPll. includes. indistl'llllllltlttl). finely pulverized ore. including mineral partieles or metallie sull'irls, (ourselumps or oversize eontaining more or less unlilwrated mineral. and a .oonsiderable quantity of inateria] of various intermediate sizes romp-rising grains of liberated mineral and gangue, 'lbe eoinpressed air admitted at the top,

through the tubular grating 35 passes up 7 said 'lroth. together with the material can ried thereby. orei'llou'ing at the top of the tank into the blunders 3G and being .'.-lttlbl V tilt] iii passage of the particles to the extent permitt-en by the rising bubbles. The coarsest rin-i'lmial and ov 1: use will therefore be retained in the sizing compartment nearest the inlet, and the suraiessively smaller sizes in the other compartnmnts, according to their passing out at the outlet This grading or sizing of uiiai'ei. l may be controlled to a large extent by the .i iustniient of: the gate 1 .37 and of the hotter 54-, making the current plan more or at various points, and all by mlje;tinei..t oi the air pressme suppl 5 veral sections of the tulmlar m ans of the valves retained in the t-Ill', at) is removed there from by the

c ator

25, 27 and discharged upon the conccntrah through the chute on ing tiible Any liberated mineral in the oversize will i e separated out by said concentrator, the remaining material with its unliberated mineral being; returned by the conveyors and 4:1 elevator lO to the will 12 for regrinding and repeated treatment, Theiinest sulfid materials dis charged through the openings 37, as also the grainsof interi'nediate discharged by the fluid pressiu'e lifts and chutes 34 are severally and so ly delivered at suitable points for such further treatment as may e applicable.

It will. thus be seen that the paratus above described is pabe of receiving the ordinary run of the mill 1.2, when run in its most E nomical manner, and Without previous c ning, that during the passage of the pulp through the apparatus the mineral values already line enou h for removal by l and is an .nna lly returned to the mill for regrincluig, .y liberated minerals therein belo in it 1 concentrator on;

(lcrt ain features oi classifier showi'iherein, so, con ad ind'cpend ently oi? the irctliin operation, are not claimed herein, cine: c ,r'ercd by the claims intin'ic, sep lratcd out by the of a divisional application filed Dec. l, 1915, Serial #64993.

Having thus described my invention, I claim: I

1. A hydraulic ore siparator comprising a tank having an inlet and an outlet at its opposite ends, respectively, provision for discharging froth at its upper portion, a plurality of sizing compartme its at the bottom, and means for admit-tin r a gaseous medium to the lower part oi said tank above the level of said compartments, said last named means comprising a filtering surface adapted to discharge streams of said medium in a finely divided state and being so arranged as to cause said streams to reach all portions of the liquid above at least the first of said compartments while permitting the free downward passage of solids into said con'ipartnients.

2. A hydraulic separator comprising a tank having an inlet and an outlet at its opposite ends, i'cspcctively, provision for dischargii'zg fl at its; upper portion, a plurality or compartments at the bottom, and means for admitting a gaseous medium to the lower part of said tank above the level. of said compartments, said last named means comprising a filtering surface adapted to discharge streams of said medium in a-finely divided state and being so arranged as to cause said streams to reach all portions of the liquid above all of said compartments While permitting the free downward passage of solids into said compa-rtmcnts.

3. A. hydraulic ore separator comprising a tank having an inlet and an outlet at its opposite. ends, respectively, provision for discharging froth at its upper portion, a plurality of sizing compartments at the bottom, and a series" of tubes collectively constituting a tubular grating extending across said tank above the level of said compartments, said tubes having filtering surfaces adapted to discharge streams of a gaseous medium in a finely divided state, and.

tubes being so spaced as to cause said' plurality of sizing compartments at the:

bottom, and aseries of tubes collectively constituting a tubular grating extending across sald tank above. the level of said compartments, said tubes having filtering surfaces adapted .to discharge streams of a gaseous medium in a finely divided state, and said tubes being so spaced as to cause said streams to reach all POllZlOHS of the liquid above said grating while permitting the free downward passage of solids between said tubes into said compartments, and fluid pressure lifts extending through said grating for separately discharging material from said comparti'nents, respectively.

5. A hydraulic ore separator comprising a tank having an inlet and an outlet at its 01 p-osite ends, res 'iectively, provision for di. charging froth at its upper portion, a. plurality of sizing comprurtments at the bottom, and a series of tubes collectively Cullstituting a tubular grating extending across said tank above the level of said compartments, said tubes having filtering surfaces extending completely tl'iereabout and adapted to discharge streams of a gaseous mediin'n in a finely divided state, and said tubes being so spaced as to cause said streams to reach all portions oi the liquid above said grating \vhile permitting the tree do\vn ward 'iassage of solids between said tubes into said compartments.

6. A hydraulic ore separator comprising a tank having an inlet and an outlet at its opposite ends, respectively, provision for discharging froth. at its upper portion, a plurality of sizing compartments at the bottom, and a series of tubes collectively constituting a tubular grating extending across said tank above the level of said compartments, said tubes having filtering surfaces adapted to discharge streams of a gaseous medium in a finely divided state, and. said tubes being so spaced as to cause said streams to reach all portions of the liquid above said grating while permitting the free downward passage of solids between said tubesinto said compartments, and means for supplying a gaseous medium to said tubes and communicating Withalternate tubes of the series at opposite ends, respectively.

7. A frothing sizer comprising a tank having an inlet at one end, an outlet at the opposite end, a top permitting overflow therefrom, and a plurality of sizing compartments at the bottom, said tank being constructed. and arranged to permit the free flow of material therethrough in a substantially horizontal direction from said inlet to said outlet, means for admitting air to the lower part of said tank to form bub bles therein, and means for directing the upward passage of said bubbles.

8, A frothing sizer comprising-a tank having an inlet at one end, an outlet at the opposite end, a toppermitting overflow therefrom, and a plurality of sizing compartments atthe bottom, an air tube grat- .ing within said tank for admitting air thereto, and a series of vertically disposed shutters Within said tank above said grating, saith-shutters being spaced to correspond with "said compartments 9. The combination with a grinding mill, of a i'rothing sizer eomprisinga tank having an inlet at ,one end, into which the com- .minuted material from said mill is discharged, an outlet at the opposite end, a

top permitting overflow therefrom, and one or more sizing con'ipartments at the bottom, and means for returning coarse material sep arated out by said sizer to said mill for regrinding.

10. The combination with a grinding mill, of a t'rothing sizer comprising a tank having' an inlet into Which the comminuted material from said mill is discharged, an outlet, a top permitting overflow therefrom, and a series of sizing compartments at the bottom progressively arranged between said inlet and outlet, and means for returning the material deposited in at least one of said compartments adjacent the inlet end of the series to said mill for regrinding.

11. The combination with a grinding mill, of afrothing sizer comprising. a tank having an inlet at one end into which the com ininutcd material from said mill is discharged. an outlet at the opposite end, a top permitting overflow therefrom, and a plurality of sizing compartments at the bot tom, of means for returning material from at least one of the compartments adjacentthe inlet end of said tank to said mill for regrinding and for otherwise discharging, the material from the remaining compartments.

12. The combination with a grinding mill, of a. trothing sizer comprising a tank having an inlet, into which the eomminute'd inaterial from said mill is discharged, and an outlet, means for admitting air to said,- tank to produce froth at the top thereofisaid tank having provision for separately retaining therein material of several sizes, and means for returning certain of said retained material to said mill for regrhinding.

13. The combination with a grinding mill, of a frothing s-izer comprising a tank having an inlet at one end into which the comminuted material from said mill is discharged, an outlet at the opposite end, top permitting overflow therefrom, and a plurality of sizing compartments in the bottom, a concentrator to which coarse material sepated out by said sizer is delivered, and means for returning the material rejected by said concentrator to said mill for regrindin g.

14. A hydraulic ore separator comprising a tank, means Within said tank for aerating a mass of pulp to separate therefrom the finer particles of mineral by flotation, and means comprising a plurality of sizing o npartments at the bottom of said tank, for concurrently subjecting said pulp to gravity treatment to separate the coarser portions. thereof into a plurality of classifications,-

said tank having provision for discharging froth at its upper portion and other provision for discharging the residue of said pulp.

1-7. A. hydraulic ore separator comprising a lanlc, means within said tank for aerating a mass of pu p to separate therefrom the liner particles of mineral liy flotation, and means comprising a plurality of sizing compartments at the bottom of said tank, for concurrently subjecting said pulp to gravity treatment, said lastrnamcd means having provision vfor removing oversize and pro- \ision for separating the coarser portions smaller than. oversize into a plurality of classifications, said tank having provision for discharging froth at its upper portion and other provision for discharging the residue of said pulp.

1U. hydraulic ore. separator comprising a tank having an inlet and an outlet at its opposite ends, respectively, provision for discharging lroth at its upper portion, a, plurality of sizing compartments at the bottom and means for admitting a gaseous medium to the lower part of said tank above the level of said compartments, said lastnamed means comprising a filtering surface suliieiently porous topermit the passage therethrongh of gases and liquids but not of solids and adapted ,to discharge. streams of said medium in a finely divided state, and said means bein so arranged as to-cause said streams to roam all portions of the liquid above at least one of said compartments while permitting the free downward passage of solids into said compartments.

17. A. hydraulic ore'separator comprising a tank having an inlet and an outlet at its opposite ends, resspectively, provision for discharging froth at its upper portion, a plurality of sizing compartments at the bottom, and a series of tubes collectively constituting a tubular grating extending across said tank above the level of said compartments, said tubes having filtering surfaces sullieiently porous to permit the passage therethrough of gases nd li uids but not of solids and adapted to discharge streams of a gaseous medium in a finely divided state, and said lllln'S being so spared as to cause said streams to reach all. portions of the liquid above-said grating while permitting the free dmvnuard passage of solids betwec said lulu-s into said com mrinn-nts.

In testimony whereof I aliix my signature, in presence of two witnesses.

DAVID Gone.