US1480884A - Method of concentrating ores - Google Patents

Description

Jan. 15 1924.

S. H. DOLBEAR METHOD OF CONCENTRATING ORES Filed Dec. 15 1920 SAMUEL H. DDLBER, OF SAN FCISCO, CLISFOR, ASQJIGNB TG PNEUTIC PROCESS FLOTATION-COMPNY, FQEW'` YORK, N. Y., A GORPORATIQN QF D- BEETEOD 0F CGNCENTRTING: GRES.

Application filed December i5, 1920. Serial No. 431,02.

To all whom it may concern.

Be it known that l, SAMUEL H. Domme, a citizen of the United States, residing at San Francisco, in the county of San Fran-` cisco and State of California, have invented new and useful Improvements in Methods of Concentrating Orcs, of which the following is a specification. y

This invention relates to the concentration of ores and has forits object the provision of an improved method of ore concentration.

The method of the present invention, While not a dotation process in the sense in which that process is understood in the art, partahes of the nature of the flotation processes of ore` concentration in. that it taires advantage of the Well known preference of a froth containing certain substances et" the class designated in the art as flotative agents for certain l,mineral and metallic sub-- stances such as metallic suliides present in ore and its equivalents. The concentration of ores by dotation is novv commonly practiced by either'the agitation froth process or the pneumatic flotation process. in the agitation froth process, the ore p ulp, consisting of the nely divided ore mixed with from 3 to 5 times its Weight of Water, together with a small quantity of an appropriate otative agent is mechanically agif tated until. the metalliferous matter forms inte` a froth which is separated from the remainder of the ore pulp. in, the pneumatic Aflotatitrc process. the ore pulp together with a -lotative agent is subjected to aeration of such .a character that a body of froth is formed and continuously maintained above the body of ore pulp, and mineral particles in the ore pulp are elevated into this body of froth vhy the levitating action of the air bubbles rising through the body of the ore pulp and are subsequently recovered from the rroth. in euch o* these iotation processes, the ore pulp together with anv appropriate iiotative agent is itself direct-ly ncted upon by a physical force, this force being' in one case mechanical and in the other case pneumatic.

My present invention' contemplates the concentration of ores by creating or produc- Vabove the lower boundary thereof. Thus, the

method of the present invention involves the production of a body of froth having a selective retent-ive affinity for certain components of the ore, and the introduction of ore directly into this body of froth from a. source independent of and out of contact with the froth forming means and under conditions such that the metalliferous matter in the ore is more readily retained bythe froth than is the angue matter in the ore. in carrying out t e method oi' the invention, any suitable amount of oily .li-quid or other/appropriate flotation agentia used and a smali amount of acid or alkali may he used alone or in addi- 4tion thereto, as may be determined .necessary or desirable by simple tests novvv known to all sltilied in the artof iiotation. The method of the invention is not, however, a dotation process, in that the ore is not agitated nor is a mixture of the ore, water andl 'lotative agent mechanically agitated or aerated as in the Weil known agitation froth and pneumatic flotation processes.

in the practice of the present invention, in its preferred form, l first produce or create a froth having a selective retentive ,aiiinity for certain components of an ore by agitating and/cr aeratinff a liquid containing! an appropriate frothing agent generally a iiotative oil to which may be added, if desired, other reagents such. as acid or alkali. Thereafter pulverized oreisintroduced into this i'roth at a point above the lower level of the froth. Anysuitahle means may be ernployed for evenly depositing the ore upon or in the froth. Thev metailiferousuparticles present in. the ore having a preference for 'the froth containing oil or other iiotative agent become attached to the froth and are 'thereby retarded or prevented from sinking,

whms the ganga@ er eathy substames pmsemt in the, om Sink with eater rapidity' and. thus become sepmaef tsfom the metallifemus pm'tih The mtl containing ihe metiercus psnricles is herear removed and the ganga@ srztaby disposed of.

t is Wen known that (me mineral or metalc substance may have a. gxeater prefe enc@ ef a mh containing a given etatv@ agent zm anuhsr mina-:val Ur metallic substmc@ Avntafge may be, taken of this phenomenfm in h@ ifea-@men of mixed ores, such as lcIesfcontaiming mixed sulides9 in acuerdan@ wh h@ method of the Wcsent invention the View Gf di'erenmly swarming ih@ dferem, metalfemus sub- Stanc hermmiamus substance Earning the geai prefeence for the froth and s; fioative @geil-il, bein@ regained in the appt pari of th@ oth which is separated imm that in th@ lcv/mr paxt; or 'the 01's may '50% created 'wo or move cmss the pmf-4 of h imvantnn in 91de? first o coeaz the mealfarcus maite? vsaily @tained in the froth, acvvnu" @the meaifeous mai;- zer ess eay waa-ined 13o sink in ik@ from and be subsaqudmy wtraate by the same or same othev sumble methofl,

ploye in th@ practi of the m'vqmscn is gm. unstable froth which 1s comfrnueusly breaking down and wntmuoasy wing re- -pacad by fresh fruth.,

Lppzamius in @rdel to Secure commet with iba oalfiw agent or with gas bubbes, and even thm Some of *.he mmeml partielles avoid auch commet and tha-@by becmn@ lest t@ otaimm En th@ method of ih@ present invemo-n? ibs commet is easlv made pesi- -ive by aeng h@ orein a, mey divided condtn recty imi@ the body :mth and '5mm source independent of ansi out of somme-t vvlzh h@ ifo-th omng 'bawdy @f liquid n the ustomay oazn pm se ses, is mcessary 'to supply Sucient power fm kaap he om in conan, mion er agitation whie in the otatinn apparaus, s@ m' auch fion of ove so saatee :reques ih@ @Xpendlzue a certain amoum 0f pvfer @r ibis purpcsa. n the pme-@ss be pressant; wemon, ik@ or@ -s'a is mais aghence a; Substantial saving in pff er n ib@ pzmice ha present invantiom, it may desmbe m feed ih@ or@ fz@ he mh new am@ and mi' The ce er vesss and to keep le m. 'amv-ding toward h@ u'her and of abe vess Wem it is die harged. This givw 1w gangu :md emrhy maiaras im@ sink thmugh the froth become @parmi/ed imm mineral or -metaic pagces which are retained in jme fo'thf Fig; a sacicna Elevation of am @pparaisuspvruarly adapted for iii-'e pf2@ ti a s *the pi'esen. inventi u;

Figa 2 jfgerspeciiv@ view @f a potin of the apparalus; and

Fig. 3 iff, a pmal sectional aefvahon ai: a sigzly mcdied fom' of @.ppmaus aape *fm* the maiis@ of the invmt *wink having atransvex'se porous madium lla naar the bottom heres The pcvou@ medium may 'be of any appvopvste @me adapted to suppv a suiah@ sa-i3? @E hquld and at ish@ 'imma pevmz: im@ passage 'upwardy therethrough of aspmpviate quantsy of s; suimbfa fic needs gas, such, for example, as air. A plurality of gas compartments 12 are provided beneath the porous bottom 11, and an appro priate gas, such as air, under suitable pressure, is admitted to the compartments 12 by means 'of valved pipes 13 communicating with a gas supply main 14.

The iquid level in the tank 10, undery normal operating conditions, is not higher than the line a. Liquid, such as water, and appropriate frothing and/or selective agent or agents are introduced into the tank l() through a pipe 15 provided at its upper end with a funnel '16. The tank 10 is also provided with a liquid discharge pipe 17, the valve of which, under normal operating conditions, is maintained closed.

A lurality of V-shaped deliectors i or troug s 18 are mounted in the upper portion of the tank 10 above the normal liquid level of the tank under operating conditions. The detlectors are arranged transversely in the tank and are parallel to one another. Each delector is provided with substantially horizontal flanges 19 andthe deflectors are arranged so that the flanges 19 of adjacent deflectors overlap. The overlapping flanges 19 are appropriately spaced so as to permit the passage therebetween of froth formed above the liquid level a.

A perforated hollow drum 20 lis provided for feeding ore or ore pulp into or upon the body of froth formed above the deflectors 18. The drum Vis mounted for rotation upon rollers 24. The perforations of the drum are preferably staggered in order to uniformly distribute the ore and to avoid channeling and breaking down of the froth. A stationary feed pipe 21 having a discharge opening or openings 2 2is mounted centrally within the drum 20. The drum is interiorly pro.videcvlv with a plurality of spaced baffles 23.

he troughs 18 project through one side wall of the tank 10 and are arranged to discharge into launders 25 mountedon the side of the tank. One or more launders may be provided for collecting the discharge from troughs 18, and in the apparatus illustrated in the drawing three such launders are provided.

The practice of the present invention in the apparatus illustrated in the accompanying drawing is substantially as follows:

Air, or othersuitable gas. is forced through` porous medium 11 into the liquid in the tank 10 and forms within this liquid a continuously rising stream kof air or gas bubbles. The liquid level is maintained approximately constant by adding additional liquid, such as water, to the tank through the, supply pipe 15. An appron priate `flotation and/sr :lectiva agent or agents aresupplied icliguid in the tank through the pipe stances, it is advisable to emulsify the flota- -tive and/or selective agent' before introducing it into the tank, since the free agent might tend to kill the froth. Froth-making gas bubbles rise to the surface of the liquid and there is formed above such surface a body of froth which graduali rises and comin in contact with the de ectors 18 is force through the apertures between the overlapping flanges 19. ln this manner a mass of froth is built up reaching in depth or thickness from the top of the liquid level (a) to or above the level of the up er froth discharge 26.

hen a suitable'depth of froth has been formed, ore or ore pul of appropriate consistenc is conducte into the drum 20 throng the feed pipe 21 and discharged into the drum through the apertures 22.

The lower portion'of the drum preferably comes in contact with the froth since it is desirable to prevent the ore from fail-ling upon the froth, thereby causing the froth to be broken down. The ore, upon discharging from the apertures 22, strikes the bellies 23, the Weight of the falling ore being suicient to revolve the drum 20, the drum being supported by the rollers 24 upon which it revolves. The speed of rotation of the drum may be appropriately varied by adjusting the .spouting velocity of the ore discharged from the feed tube 21. vThe ore passes through the perforations of the drum into the body of froth in the tank '10( The froth rising through the apertures between the overlapping flanges 19 immediately bev low the drum receives a charge of orc Gangue matter, having no preference for the selective agent in the froth, sinks out of or into the lower portion of the froth, and is caught in the V-shapedtroughs or deilectors 18. and is discharged through the wall of the tank into the launders 25. From the launders 25 such gangue matter may be conducted to any suitable place for disposa or retreatment.

Mineral particles exhibit a tendency to remain in the froth while gangue particles exhibit a tendency to fall through the froth and for these reasons the froth and more particularly the top portion thereof becomes enriched in metalliferous matter. The entire body of froth is given a longitudinal movement, that is, a movement from the feed end of the apparatus towards the discharge end. ln other words, as viewed in the drawing, the bod of frotli moves from left to right, and 1s discharged into launders 28 and 29 through discharge openings 26 and 27 respectively. This movement of the froth is due to the fact that the froth is ejected through the spaces or apertures between the flanges 19 with a lateral ent, and auch lateral movement is .ed to the overlaying froth. lf delll) sired the discharge opening 27 may be close When open, this discharge openin enables the froth to be removed at two di ferent levels thereby obtaining concentrates' of dierent grades or of different charsuch cases be disposed of by the first launder 25 separately from the product or products deposited in the V-shaped troughs near the discharge end of the apparatus.

Severai diiierent products may, if desired,v

Je collected in this way. Thus, three different products can be collected from the three launders 25 and two additional different products can be collected in the launlders 28 and 29. ln this manner, it is practicable to carry out with ease various procedures of dierential separation or concentration of ores.

Fig. 3 illustrates the method of practicing the invention in an apparatus wherein the froth is produced by agitation. in agitation chamber l1 communicates by means of an opening l2 with the tank l0' which is in all essentials identical to the tank l0' shown in Fig. i. A shaft 13" adapted for rotation is suspended Within the agitation chamber li and carries at its lower end agitation blades la. Liquid such as Water and appropriate frotliing and/or selective agent or agents are introduced into the agitation chamber 11 through a pipe i5 provided at its upper end with a funnel i6.

After an appropriate quantity of liquid, such as Water, containin a dotation agent or agents has been introduced into the agitation chamber 1l', the shaft i3' carrying the agitation blades le is rapidly rotated thereby violently agitating the liquid contained in the agitation chamber il and incorporating a quantity of air with. the liquid; The liquid thus incorporated with air passes into the tank 10 through the opening 12 where the air rises to the surface of the iiquid in the form ot a froth. number of agitation chambers may be placed along the sides of the tanlr 1G thereby assuring a uniform formation of froth throughout the entire length of the tank l0 It will be readily understood by 'those skilled in the art-of flotation metallurgy that many of the deveiopments in dotation may be easily used in the practice of the present invention. lt is not believed to be necessary to further cite specific directions to other types of apparatus suitable for nastiest producing an appropriate froth nor for separating the mineral bearing froth from the gangue, nor to describe 1n detail the many Qoils or flotative atgents and other reagents which may be used in the practice of the present invention.

I claim:

1. rEhe method of concentrating ores which comprises distributing pulverized ore evenly and Without agitation directly into contact with a substantially non-agitated body of froth having a, selective retentive aiinity for certain components ofthe ore, permitting other components to sinh through the froth, and separating the components reta-ined by the froth.

2. The method of concentrating ores which comprises producing a froth having a selective retentive aiiinity for certain components of the ore, distributing ore into the froth at a point above the lower boundary of the froth, permitting certain components of the ore to sink through the froth, and se arating the components retained by t e froth.

3. The method of concentrating ores which comprises aerating a liquid containing a frothing agent to produce a froth having a selective retentive aiiinity for certain components of the ore, distributing ore into the froth at a point above the lower boundary of the froth, permitting certain componente of the ore to sink through the froth, x

and separating the components retained by the froth.

d. The method of concentrating ores which comprises producing above the surface of a. liquid containing a frothing agent a froth having a selective retentive aiiinity for certain components of the ore, distributing ore directly into said froth -roni a source independent of and out of contact with said liquid and under such conditions that certain components of the ore are more readily retained hy the froth than other components ci the ore. and recovering the components more readily retained by the froth by froth overflow.

5. lThe method of concentrating ores which comprises aerating a liquid containing a frothing agent to form above the liquid a froth having a selective retentive aiiinity for the metalliferous matter in an ore, distributing ore directly into said froth from a source independent of and out ot Contact with said liquid and under conditions such that the metalliferous matter in the ore is more readily retained by the froth than is the gangue matter in the ore, and recovering metalliicrous matter from the froth by froth overtiovv.

6. The method of concentrating ores containing diiferent metalliferous substances which comprises producing a body of froth having' a seiective retentive anity for the llO metalliferous matter in the ore, distribent inthe ore to arrange themselves in the uting the ore directly into the froth at a iroth'in zones in. each of which a particular point above the lower boundary of the froth metalliferous substance predominates, and 10 whereby the metalliferous matter in the ore separatelyrecovering the metalliferous sub- 5 is more readily retained in the froth than stance in the dierent zones of the froth. is the angue matter in the ore, permitting the dierent metalliferous substances pres- SAMUEL H. DOLBEAR.

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