US2358506A - Means for separating materials - Google Patents

Description

Sept 19, 1944.

R. G. GUTHRIE ETAL MEANS FOR SE'AATING MATERIALS Filed Nv. 15, 1940 .AITORIiEYf Patented Sept. 19, 1 944 vUNITED STATES OFFICE wm@ f A FOR srrlimrnvdmmmps v Y Robert G Gutlirie and Oscar-J, 'WilborQ Chicago'Y Ill., assig'jirs' tov Chicago -lByeProdlucts' Corpo-z. ration, Chicago, Ill., a. corporation ofljllinoisj Application November 15, isilifci',seriallviagasc,

V1 Clai vm. (C1. ZQB'lll) Theu invention relates; to separation; of materials having different characteristics, and `in its more specificaspectshas to do with meansjfor separating certain mineral valuescontained yin Aan ore lfrom the rock of' the ore.v

'I'he particular problem which thisv inventionV solves is the separation-ofvermiculitev vfroni the 'accompanying rock formations, -largelu-ylgranite,

Y quartz, or the like.

Vermiculite is a laminated mineral consisting of thin akes of silicon dioxide with interleaved impurities largely in the-form ofzmetallicoxides and containing combined water and moisture.

The flakes or plates of silicon'dioxide-may4 be extracted from the ore" by a process; described inPatent No. 1,898,774, and'they Ythenf-lelhibilt the property of ahighly effective and eflicient adsorbent. Thesenished adsorbent silica flakes are termed Lamisilite Y In vthe process of producing. Lamisilite, .the rock containing-the ore is mined to -f-reeit largely asv possible from` the; accompanying v:impurities consisting chiefly of granita-quartz-,jarld .similari stone; The ore with-an unavoidable percentage of rock is crushed tofthe desiredsizefwhich, gin

a particular instance, .is in ,-.irregi1.la 1' .v particlesi of; a -majordimension of from 0.5- to 0.752. @The size Amaypvary over a considerable range.V jIf smaller iiakes are desired; the size of thegcrushed ore isvredu-ced accordingly. The process and .machine of our 'invention operate'uponvavprincilple Vwhich ma-kes size of no importance.

"Since the ore- -is a relatively soft, laminated mineral, it breaks into more or less flatsided `particles-cf irregular outline. The accompanying stone breaks yinto particles which haveffmore lnearly the samediameteriin all. directions. "e

VWe have observedgthat thciparticles Vof verfmiculite. ore, whenallowed `freedom to do so, y will 10eme to rest upon-a flat' face; Y'Iheparticlesot -stoneihaving no :pronounced-.planes of cleavage will generally be 'foundfto -apprcximate=the\shape of pebbles, i. e., more nearly sphericaL-and are rless stably*supported-.omarmt surface.- -y'I'he-glats ided particles of .Verntculite have avvidebase and lower center ofigravity-.th-an have the vparti- .cles iof stone, `whenboth will pass-...the samel'size screen..V l f VWe take advantage of the observed character- Vistics of the .two kinds o f materialso ure a separation. by disposing Y` the A.t',wo-rnat ein fthe form of a. miXture, uponanginclinedffplane A`and.iir'nparting alimited amountfofkineticfenergy to the particles `'of .the .mixtures The Y`parti-cles with fat sides, i. le., .the .ammaecar greaterdimcmty, mceseepcig the incline. than wi1l..the.more, n` early rounded particles of. stone.

Hence, .theparticles vof stone will runoff. first. .This pmpertyof thepartcles of stone running aheadaof the particles of. vermicfulite is present,

even; if-ithepartilcles of stone should, by virtue ot conchoidal'liracture assume, theV approximate shape of -tetrahedrons- The lstone.- particles would, nevertheless, for the same .screen siz'e, ycarry the .center-otgrayity higher above the suppcrtingfplanethan wouldparallel-.sided particleslofQlaInir-lated material. Therefore, we have foundthat! byaimparting. kinetic energy to the ymixed. particlesonan inclined plane, the parti- .c-leslof. stone fwillin[general travel downward Vgsimilarjuncture,,oitwo-or more types of particles having `ciiiiererrees` in Veffective area ,of base for 'the sarne mas's, .or diii'erenc'esin leil'ective'height of. .ce n t er ongrayityionthe `.sarnemass Wehave .observed.ina r-loose waypfspeakng, that the ,particles of stone ,have a. .greater .rollability .than .thaparticlesof vermilculite, even .with fairly widedifference ii'ascreendiameterand, therefore,

i Ythe .particlesof stone -can be Lcausedt'o rolloff .an.ineli ned .plane .and the ,vermiculite .particles A. be,rf ,tainedfuponit, whenthe particles are livened v,1 1p..by.111111ill'lirlg"..kinetic energyto them.'l

Ijn-orderto `make Ythe fprocess continuous, we

.haveaprqvided a .table wthla travelling surface such..as-..a conveyorbelt.vv The...moving` surface travels in a direction oppositepto the .travel of .the zparticles. .By-...regulating-theinlclination of thesurfacailthe kineticenergyinput tothe parti- Yclesand the .negative travel -of .theltable a. com- .Y ninationpfffactions vvis ,readily ,obtainedV when the .particles of vermiculite travel backward `1 while .the V`.par'ticles..of .stone travel 4forward, relative. to

.a hired poin-tpnthe table. rE lence,-vthe two types .o iparticle'sare caused. to.travel inoppositedi-rec- -..ti o n`s,. whichis anidealgcond-ition for separation.

- Thefxni'xtureof `.materials .tobe separatedmay be...treatedeither wet; ordry. In :the Wet treatment suflicient Waterisiadded .to .coat with mois- .turetheparticles oflinate'rial. .Wetting ofthe .mixturetendskto -cause the particles of vermicu- .liteato-.adhere to thel support-ing surface, due to VKthe i'liatness of such partclesuandftheir'relatively large" area of Contact with thesupporting` sur'- trace, whereasrtherparticles,o .,.rocladue to'their l` roug'liness and fr relatively ,.srnall i :area .,gf Y contact 55 with the supporting Surface, have relatively y little materially less IcostY than is'possible when hand l .eppeetu 'les our inventionl Y- 1 s Y mains, we would then have a mixture of 95% 10 vermiculite and 5% rock, such as granite .101` 5.1,-1 quartz,insoluble in sulphuric acid. Thismix ture, to produce the adsorbent silica` flakesrer ferred to, is leached in sulphuric acid. Approximately 56% of the vermiculite-is removed, inth form of acid soluble impurities, during the leach-V ing operation, producing silica. flakes, in amount equal to 41.8% of the original 95%' of vermiculite. But the residue also includes the original 5% of acid insolublerock and is, equal to 46.8%

of the original `100% jdr mixturecomprising195% vermiculite and' 5% ,rock. -Accordingly, in the i residue after leachingwe have a mixture of 89.32

parts 'silica fiakes, knownas Lamisiliteffand 10.68 parts rock. Assuming pure "Lamisiliteto f have an fadsorptsive power jfor, lwaterjof j 20%.v of its own weight, a' mixture of j89 3 2% Larnisilite and 10.68% rock'wil1 nadsorb butr '1`7.86%1 of its weightm water.

It is thus` apparent thatthefpresence ofbut"4 5% of rock in' the verrniculitenis'bbjectionable,

particularly in commercial operations :in Vwhich large quantitiesof the adsorbent silica flakesaie used and where mixirnum'zpoweruofadsorption: I

from the vermiculite ore, as is the present practice, about 5%,of rock cannot be removed,'jdue to the mechanical treatment which the prereceives at themine, rock.I remains Vthe v ermiculite and the'eiciency` of the rinallprod- 40 suchthatthe 'upper' run of the belt travels upuct, in practice,isreduced.' While it possible,

by. hand picking,tolreducetherock content to as low as approximately 5%.V that requirente@ @are and considerable. 'time 1F01' 'that l ,reofn handpickingj is notlpracticable from fthecom- '415 s'erve's'to'spread materials vdeposited upon the upy per run ofthe belt transversely thereof and to impart kinetic energy to the particles of such -materials.- -Al`so, it willbe clear that Ythe upper of 'belt I is restrainedagainst transverse mercial standpoint and would lrender the `cost of the iinal product prohibitive. By ourmethod above outlinedit is possible-to separate the particles of rockjrom the vernliculite muchfa'ster than ,brhand picking. .andsolefffeerltlvthat 50 practicallyA no rockv ispresentV in thev separated Y vermiculite; which is conducive Ltoythe production of 1 substantially l pure adsorbent lsili'ca akesY at picking is employed.'

Briefly; our',invention apparatus forseparating two materials having, different characteristics suchthat, when'a'mixture of such I materials is placed upon fa surface and kineticYen ergyis.transmitted'to' the so fen'ergyv to thematerial particles and assists in `Af-"rapid'se'paration' thereof'in the manner above "explained:V

' irilned 'supporting particles of the' mixture",VV ftheV particles of ione'of the materials will ifreveLdQWnwardpVer the' `Y`i151- tages of 'our'inve'ntion will Vappearv` 'from the dehe dra The lattervare pivoted at. their upper ends touprights I8vv and are adjustably secured at their lower portions to 'frame 6 by bolt and slot means 5. Belt I is thus supported for travel aboutthe rplls V2 and 3, with its upper run disposedv-at-an'inclination upward toward one end A- of frame- 6, which end, for purposes of descripf -tionffriiap be' designated the forward end of the `vframe- The latter is supported on suitably disposed c oil springs 1, 1a, 1b, and 1c, to facilitate ljvibration of the frame and parts mounted thereo n, 'as will be explained more fully presently.

A pulley 8 secured on the shaft of roll 2, re-

" ceives a belt I9 which passes about a pulley '9 of I' a speed -educingunit I0 of known type, disposed adjacentone side of lframe 6. Unit I0 is suitabliT secured, as'by bolting, to aY platform 20 extending transversely of and welded or otherwise suitably s ecured to,v the frame'l20. An'elef'ztric-rnotor II,

bolted ori-otherwise suitably secured to platform 20, has'driving connection to unit I0, by means of abelt2 I passing about a pulley 22 secured on the `v shaft'of motor I Il andabout apulley 23 secured on thedrive shaft 24 of unit IIJ. A second pulley 25 WVisseured on shaft24 and receives a belt 26 passi'r'igaboutra pulleyiZ'I` secured on a shaft 28, rotatfj '-ablyf mounted ina bracket I2 bolted, or otherwise is important.; In'hand picking 'the rockparticles" '3 center o f-frame. "An eccentricweight 29 is se- -curedon shaft `28 for rotation therewith. When j"the motor lI I is in operation, belt I' is driven ui'tably secured, to platform 2J at the transverse therefrom at relatively lowspeed, the drive being 29 serves to impart vibration to'frarne 6 and belt fl ,l generally transversely thereof. This vibration swinging movement and travels substantially in a fixed plane, and when weight 29 reaches its upreaches its lowermost positionit exerts its maxi- The eie'ctof weight 29v is, in each instance, sup- `j'plerrnented by the reactionsV of springs 1, 1a, 1b Vand 1c".V In-that manner, the upper run of belt 'I`y isfvibrated vertically, vwhich imparts kinetic 1A` downwardly `and forwardly inclined trough I3 extends 'from adjacent roll 3 to a forwardly hdod I [mounted at thefront'of frame 6. Trough I3 is disposed to discharged material received thereby downward in front of the opening v*ofi-lio'odflkptowhich'fluid under pressure, conveniently air, is supplied 'by a conduit I5, from 'i1-a suitable source (not shown), such as a blower -pof'anylsuitable known type. A receptaclel is disposed adjacent'and below hood I4, atthe front thereof, and is fseparatedinto a plurality of -com- `75`- `:"p'artinents'@disposed"parallel with: the opening-cf hood I 4. AsY shown, receptaclel is dividedv into two compartmentsby apartition 1I 1f. In' practice, however, receptacle IzIma'ylbe provided with any suitable numbereo'f compartments, depending-upon the. .naturepi lthe,material being processed, the forcezofthe f luidqo,` air blast discharged from hoodIlIv and related factors. It will be clear that when particles of material are discharged from trough I3, the lighter particles will be blown by the air blast to a greater distance than the heavier particles. Accordingly, by properly regulating the air'blast for a given material, the smaller particles of that material will be deposited in compartment ISa of receptacle I6 and the larger particles will be deposited in compartment I 6b. If three compartments were provided, the smallest particles would be deposited in the outermost compartment, the next smaller particles in the central compartment, and the largest particles in the rst or innermost compartment. The material is thus automatically graded or classified according to particle size, and may be separated 'nto as many grades as desired, within limits. That is of importance where the material is to be subjected to treatment Athe duration of which depends, to a greater or lesser extent, upon the size of the particles of the material, as will appear more fully presently.

The mixture of materials to be separated, such as crushed vermiculite ore comprising particles of rock and particles of vermiculite, is delivered onto the upper run of belt I in a suitable manner.

Conveniently, a delivery spout 30, which may lead from a storage bin (not shown), is disposed with its lower end a short distance above belt I, at the lower portion thereof. The ore discharged from spout 30 is spread upon the upper run of belt I, by the transverse vibration thereof, such vibration, supplemented by the vertical vibration of this run of belt I, imparting kinetic energy to the particles of rock and vermiculite. Due to the characteristics of the rock particles, previously referred to, they roll down the inclined belt and are discharged from the lower end thereof, whereas the particles of vermiculite, due to their characteristics, tend to remain more or less in repose' upon the belt or, if they tend to move downward over the belt travel at much lower speed than the rock particles. The speed of the belt is so regulated as to more than oi-svet any downward travel thereon of the vermiculite particles while permitting free downward travel of the rock particles. The net result is that, with respect to a fixed point at the lower end of spout 30, the rock particles travel downward over the belt and are discharged from the lower end thereof, whereas the vermiculite particles remain upon the upper run of the belt and travel upward therewith. That will be clear from Figure l, in which the more or less rounded or pebble-shaped rock particles are indicated by the reference character 1', and the at low lying vermiculite particles are 'indicated by the reference character 11. It will be understood that, in Figure 1, the particles of both the rock and the vermiculite are exaggerated in size, for purposes of illustration only, and, in practice, these particles would be rather small,

^ having, for example, a major dimension of from .05 to .75". We thus take advantage of the different characteristics of the rock particles and the vermiculite particles to effect substantially Vcomplete separation thereof in a highly efficient manner which renders possible handling comparatively large quantities of ore as a continuous operation, with resulting increase :inY production andi-decreased cost." `f 'Theseparatedivermiculite particles 1J areV dis.- charged' from theupper end ofthe-belt! into trough I3`,"from' which ,theyy are discharged and automatically gradedaccording to size, inthe mannerY above described. .We thus both separate the vermiculite particles from the rock particles and grade or classify the vermiculite particles according to size, in a single continuousr operation.

`As has been previously explained, the vermiculite particlesare leached in sulphuric acid to produce the desired highly adsorbent silica akes.

We have determined by experience that there is a certain optimum leaching time period for vermiculite, dependent largely upon the size of the particles being treated. In general, if the particles are small, they should be leached for less time than should appreciably large particles. If the optimum leaching time is exceeded, the adsorptive power of the resulting silica iiakes will be reduced. It will be seen, therefore, that if a batch of vermiculite particles varying widely in size is leached, either the larger particles will be insuflciently leached or the small particles will be leached for too long a time. YThe net result is. that the silica ilakes produced from such a batch will have less adsorptive capacity than would be the case if the particles of the batch to be leached were all of the same size and were leachedL for the optimum time for that size. By classifying vthe separated vermiculite particles according to size, in the manner above explained, we render it possible to provide batches of particles of approximately the same size. Each batch may then be leached for the optimum time for the size of the particles of that batch, thus assuring that the resulting silica akes will have maximum adsorptive capacity, which is of importance for obvious reasons.

While we preferably provide a multi-compartment receptacle for receiving the particles of vermiculite segregated or graded according to size, by the air blast, that is not essential to our invention. If the receptacle be omitted, the vermiculite particles may be permitted to accumulate in adjacent piles, the size of the particles decreasing in accordance with the distance of the respective piles from the hood. Also, a receptacle for the particles of stone discharged from the lower end of the belt is not essential, though preferred, and may be omitted if desired. Y

It will be understood, as above indicated, that variations maybe resorted to without departing from the eld and scope of our invention, and we intend to include in this application, in which the preferred form only of our invention have been illustrated and described, by way of example, all such variations asfall within the scope character that the upper run thereof is smooth and permits free downward travel therealong of Y f the generally rounded particles of said one material while retarding by friction only downward tratelf therealong of the general1y-at;partic1es shaft and: therebyV imparting vertical v ibratory movement'to said upper run during the travel of said belt, by means of said weight, effective for impartingknetic energy tothe particles-of mate- 5 rials.

" .ROBERT GQ GUTHRIE. OSCAR J. WILBoR.

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