US2139358A - Vermiculite ore treatment - Google Patents

Vermiculite ore treatment Download PDF

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US2139358A
US2139358A US72530A US7253036A US2139358A US 2139358 A US2139358 A US 2139358A US 72530 A US72530 A US 72530A US 7253036 A US7253036 A US 7253036A US 2139358 A US2139358 A US 2139358A
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screen
vermiculite
drum
impurities
particles
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Ericson Richard
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UNIVERSAL INSULATION Co
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UNIVERSAL INSULATION Co
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    • BPERFORMING OPERATIONS; TRANSPORTING
    • B07SEPARATING SOLIDS FROM SOLIDS; SORTING
    • B07BSEPARATING SOLIDS FROM SOLIDS BY SIEVING, SCREENING, SIFTING OR BY USING GAS CURRENTS; SEPARATING BY OTHER DRY METHODS APPLICABLE TO BULK MATERIAL, e.g. LOOSE ARTICLES FIT TO BE HANDLED LIKE BULK MATERIAL
    • B07B13/00Grading or sorting solid materials by dry methods, not otherwise provided for; Sorting articles otherwise than by indirectly controlled devices
    • B07B13/003Separation of articles by differences in their geometrical form or by difference in their physical properties, e.g. elasticity, compressibility, hardness
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10STECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S106/00Compositions: coating or plastic
    • Y10S106/03Mica

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  • the present invention relates to a. procedure and apparatus for dealing with mine-run vermiculite or analogous ore whereby to prepare it for further use, particularly for expansion by the 5 process described in United States Letters Patent 1,963,276 or by a similar procedure, and the method is based upon certain physical characteristics of the vermiculite and the associated rock impurities described hereinafter.
  • One of the principal objects of the invention is to segregate the valuable vermiculitefrom its gangue, a further purpose of the invention being to break down the larger vermiculite flakes, that are too bulky or of too great size ,for proper l expansion, into smaller flakes and to grade the latter so produced to a maximum thickness limit.
  • Another aim of the invention is to breakdown lumps of vermiculite and impurities into their components, an additional object being to process 20 wet or damp ore and to provide means by which the vermiculite may be dried.
  • vermiculite which is sometimes referred to as hydrated biotite mica, has the unique property of expoliating or expanding into many times its 25 original volume when properly heated, the product so formed having heretofore been used to advantage as a heat-insulating materialas well as for an aggregate associated with cementitious agents.
  • the vermiculite as found in nature is often associated with rock impurities which in the past have been difficult to remove.
  • these impurities are principally pyroxenite and syenite, and these 35 sometimes comprise as much as 67% by weight of the entire mass and they are well dispersed throughout the vermiculite, and, in fact, not infrequently the vermiculite is superficially attached to particles of impurities, and, in other 40 cases, particles of vermiculite and impurities are intermingled or interspersed, forming lumps or conglomerates, and the ore is often in a wet or damp condition due to ground water and to atmospheric conditions.
  • this lumpy, damp, comparatively-lean mixture of vermiculite and foreign matter may be made into dry, graded flakes of vermiculite, containing less than 7% impurities, which are very well adapted for ex- 50 pansion by the process disclosed in the United States patent referred to,
  • One method now in use consists in passing the mine-run ore over revolving grizzles to remove the larger lumps, the material passing through 55 the grizzles being screened on a vibrating-screen having openings between one-quarter inch square and No. 10 mesh, some diillculty having been experienced in screening wet ore through a No. 10
  • the new process takes advantage of the difference in shape and disintegration'properties of the impurities and of the vermiculite, the particles of vermiculite being flat and comparatively thin in one dimension, while the particles of impurities tend to have a spherical or cubical shape with all dimensions about the same.
  • vermiculite particles When vermiculite particles are disintegrated, especially by being subjected to a shearing action parallel to the planes of cleavage, the large flakes are broken upor disassociated into thinner ones which often have the same area of the flat side 55 as the original particle, thisiiaking or dissevering being considerably facilitated if the particles are moistened.
  • the particles of vermiculite and impurities are disintegrated to pass through slotted openings which are just sufiiciently-wide to permit .the.pas sage of the vermiculite flakes edgewise by the shortest dimension, and then passed "over a square-opening screen, the widest ldimensions of which are equal to, or preferably larger than, the width of the slot, then a separation or segregation of the flake-like vermiculite from the cube-like impurities take place.
  • the vermiculite flakes, scales or plates, because of their much greater lengththan their width, will be caught and retained on, the screen while the impurities,
  • the vermiculite that may have passed through 'the. square screen with the impurities can be recovered by'subsequent aidedby the-fact that they'do ,not disintegrate as quickly-as the vermiculite.
  • Figure 1 is a substantially-central, longitudinal, vertical section through the apparatus, with parts more or less broken away;
  • Figure 2 is an elevation of the right-hand end of the appliance
  • Figure 3 is a vertical cross-section on line 3-3 l of Figure 1;
  • Figure 4 is an enlarged, fragmentary cross section through the lower portion of the multiple revolving drum, showing the three types of screens, used, and illustrating also one of the several cylindrical grindingerods; and
  • Figure 5 is a fragmentary cross-section through the middleslotted drum on a still larger scale.
  • This apparatus comprises an inclined, multiple, revolving drum or trommel, characterized as a whole ll, having around its periphery three, concentric drums l2, l3, and H, the inner one of which is formed of a number of longitudinal,
  • these bars [5, l5 are spaced apart three-quarters of an inch at their closest points which 'is'sufilciently far apart to permit the properly-reduced material within the drum to pass to the second orgnextouter drum.
  • This inner drumor grating accommodates a number of loose, solid-metal grinding-rods l6, is of substantially the length of the drum and bearing on its inner surface, these grinding-rods during the rotation of the drum assuming positions somewhat analogousto those indicated in Figure 3, such rods acting during the revolution of the drum to provide a shearing action on the particles (if-vermiculite substantially parallel to the planes of the flakes of which they are made 'ii ana also to apply a grinding force to the parti'cles of impurities.
  • the second or next outer drum I3 comprises a slotted grill made up of a large number of parallel rods ll, 11 of the shape in cross-section as shown in Figure 5, being somewhat of inverted -V -shape o'n'top with narrow slots l8 between their upper portions, the spaces I9 outwardly be 'yond such narrow slots diverging or flaring outwardly as is fully depicted; whereby the crosssection of these metal bars l1 forming the slots l8- l9 is such as to prevent binding of the vermiculite' fiakes which tend to pass therethrough,
  • each slot 18 in the present device is .04 inch and such slots may beof any length greater than one-half inch.
  • the outer drum l4 consists of a woven-wire metal-screen having openings 0.078 inch square.
  • the compound drum is provided with a ring-gear 23 in mesh with a driving-pinion 24 on the shaft of reduction-gearing 25 driven by an electric-motor 26, all of these features being of the usual type for revolving drums.
  • the drum At its more elevated end the drum is closed by a wall 21 through which an inclined chute 28 extends a slight distance into the drum and the other, or lower, end of the drum is closed by a wall 29 through an opening in which an inclined, reciprocating, slotted screen, characterized as a whole 3
  • is supported and guided in its inclined relation'by a plurality of rollers 35, 35 andis vibrated back and'iorth by a power-driven eccentric 36 connected to the underside of the delivery chute 31 of the screen by a connecting-rod 38, there being nothing novel in the particular mechanism for actuating this screen.
  • 4 is housed in a casing 39 through the opposite end walls of which'the chute 28 and the screen 3
  • the appliance At its lower end the appliance has a chute 41 for the discharge therethrough of the cleaned, sized vermiculite which is delivered thereto in any approved manner from the outer screen
  • the operation of the appliance is substantially as follows:
  • the impure ore as it comes from the mine is passed through a three-quarter-inch revolving grizzle to eliminate the larger pieces of impurities and it then enters the revolving multiple-drum through the inclined chute 28.
  • the lumps or conglomerates of impurities and vermiculite are shattered, the larger pieces or boo of vermiculite are flaked, and the bigger pieces of impurities are broken up or disintegrated by the action of the metal grinding-rods IS.
  • the slots of such vibrating screen are of such width. as to allow the vermiculite to pass therethrough edgewise, but the larger pieces of impurities are retained on the screen and are removed by sliding down the bars of which the screen is made and delivered at the outer end of the screen structure exterior to the drum housin or casing.
  • the spacing of the reciprocating-screen bars is such that they are closer together the farther away from the entrance chute 28, because the vermiculite flakes are thinner and the impurities are smaller as they proceed down the screen due to their being subjected to more grinding action by the rods i6.
  • Flakes of vermiculite and particles of impurities that are of sufliciently small size pass through the openings .of the intermediate slotted screen l3 and onto-the square-opening screen l4.
  • Flakes thatare larger than .078 inch square in area will be retained on and delivered Irom screenl4, while all impurities and flakes that are under .078 inch ,will pass through such outer screen 'and be delivered through the conduit 42.
  • the clean vermiculite passes through the exit 4l and the portion passing through the squareopening screen l4 drops through the duct 42 into another apparatus constructed according to the same principle but with different dimensions so as to operate on smaller sizes, or it is cleaned by other means that are adapted to act on small sizes of vermiculite ore.
  • the mine-runore which has first passed through a three-quarter-inch grizzle to remove large-pieces can then be treated in an apparatus similar to that illustrated and described with the exception that no breaking or grinding rods l6 are employed and no vibratory screen 3
  • the employment of such a device also facilitates grinding of the impurities and flaking of the vermiculite in the regular apparatus, as there is no buffing effect due to the fines.
  • vermiculite flakes can be split into thinner ones when subjected to a shearing force parallel to the planes of the flakes and that this splitting is greatly improved by moistening the vermiculite particles, and in this connection it is to be remembered that besides vermiculite, this principle can be applied to any cleaning problem in which flake-like particles are to be segregated from round or cubical particles of a friable nature.
  • the larger pieces which do not as first pass through the inner drum, as well as those remaining on the middle. drum are carried up by the rotation of the drums and dropped onto the reciprocating screen and those particles which pass through the latter drop onto the lower part of the inner drum and are again acted upon by the grinding-rods, this action occurring repeatedly if necessary.
  • a rotary'trommel having three screen-drums inside of and spaced from one another, said innermost screen-drum having longitudinal slots, said intermediate screen-drumhaving narrower longitudinal slots, said outer screendrum having apertures each with its two dimensions substantially equal, and with such dimension greater than the width of the slots in the intermediate screen-drum, means to rotate said trommel, means to introduce the impure ore to be treated into said innermost screen-drum, a plurality of free elongated grinding-rods in and disposed lengthwise of said innermost screendrum to apply shearing forces tothe vermiculite particles therein substantially parallel to the planes of cleavage of the flakes .0!
  • the invention is defined by the appended are composed to divide such particles into thinner flakes and to break up the impurities into smaller pieces, means to deliver the vermiculite particles .which fail to pass through said outer screen-drum, and means to separately discharge the impurity particles which pass through said outer screen-drum.

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Description

Dec. 6, 1938,. R. ERICSON VERMICULITE ORE TREATMENT Filed April 5, 1956 2 Sheets-Sheet l Q NH mm MN Q [fa/6722b?- Ric/2am! lrwaon,
T R. ERICSON VERMICULITE ORE TREATMENT Dec. 6, 1938.
Filed April 5 1936 2 Sheets-Sheet 2 Patented Dec. 6, 1938 PATENT "OFFICE,
v 2,139,358 mnmcmm one TREATMENT,
Richard'Ei-icson, Chicago, 111., assignor to Universal-Insulation Company, Chicago, 111., a corporation of Illinois Application April s, 1936, Serial No. 12,530,
. 7 Claims.
The present invention relates to a. procedure and apparatus for dealing with mine-run vermiculite or analogous ore whereby to prepare it for further use, particularly for expansion by the 5 process described in United States Letters Patent 1,963,276 or by a similar procedure, and the method is based upon certain physical characteristics of the vermiculite and the associated rock impurities described hereinafter.
l One of the principal objects of the invention is to segregate the valuable vermiculitefrom its gangue, a further purpose of the invention being to break down the larger vermiculite flakes, that are too bulky or of too great size ,for proper l expansion, into smaller flakes and to grade the latter so produced to a maximum thickness limit.
Another aim of the invention is to breakdown lumps of vermiculite and impurities into their components, an additional object being to process 20 wet or damp ore and to provide means by which the vermiculite may be dried.-
vermiculite, which is sometimes referred to as hydrated biotite mica, has the unique property of expoliating or expanding into many times its 25 original volume when properly heated, the product so formed having heretofore been used to advantage as a heat-insulating materialas well as for an aggregate associated with cementitious agents.
The vermiculite as found in nature is often associated with rock impurities which in the past have been difficult to remove.
In certain natural deposits these impurities are principally pyroxenite and syenite, and these 35 sometimes comprise as much as 67% by weight of the entire mass and they are well dispersed throughout the vermiculite, and, in fact, not infrequently the vermiculite is superficially attached to particles of impurities, and, in other 40 cases, particles of vermiculite and impurities are intermingled or interspersed, forming lumps or conglomerates, and the ore is often in a wet or damp condition due to ground water and to atmospheric conditions.
By the present invention this lumpy, damp, comparatively-lean mixture of vermiculite and foreign matter may be made into dry, graded flakes of vermiculite, containing less than 7% impurities, which are very well adapted for ex- 50 pansion by the process disclosed in the United States patent referred to,
One method now in use consists in passing the mine-run ore over revolving grizzles to remove the larger lumps, the material passing through 55 the grizzles being screened on a vibrating-screen having openings between one-quarter inch square and No. 10 mesh, some diillculty having been experienced in screening wet ore through a No. 10
screen. The oversize retained on the %,-inch screen isground in a swing-hammer mill and re- 5 circulated until all of it passes through the quarter-inch openings, such sized ore being then treated on a Sutton, Steele and Steele air-table which separatesthe vermiculite from the impurities, such segregation not being complete, as usually over of the apparently-clean vermiculite constitutes impurities. Itis sometimes found of advantage to'separate the minus quarter-inch plus .IO-mesh sized oreinto' two sizes before cleaning on the ai'r-tables, The ore is not dry except whenclimatic conditions dry itnat- Qurally. The damp, seemingly-clean,- vermiculite is then shipped to the expanding plant-for further treatment, and an examination of the'flakes will show that some are as much as 0.075 inch in thickness, thisbeing too thick 'forproper exfoliation by the process-referred to.
By thevpro cedure followed in accordance with this. newlnvention, however, it is possible to workdamp ore and to remove-the impurities from the vermiculite and at the 'saui e'ti'me to disintegrate the flakesi'rito thinner ones graded to a suitable maximum-thickness limit. A mixture of thick and thin vermiculite flakes is not uniformly expanded or exfoliated by any of the commonly used methods of expansion, because, if sufflcient heat be used to expand the thicker flakes properly, the thinner flakes will be overheated, and. consequently, there is a maximum limit for thickness which should not be materially exceeded to obtain desirable exfoliation of all the particles undergoing treatment.
As explained hereinafter, all of the abovenoted operations can be effected in one apparatus, although other types of appliances that will require various steps may be employed and still be within the scope of the invention. The material can also be dried during the processing.
The new process takes advantage of the difference in shape and disintegration'properties of the impurities and of the vermiculite, the particles of vermiculite being flat and comparatively thin in one dimension, while the particles of impurities tend to have a spherical or cubical shape with all dimensions about the same.
When vermiculite particles are disintegrated, especially by being subjected to a shearing action parallel to the planes of cleavage, the large flakes are broken upor disassociated into thinner ones which often have the same area of the flat side 55 as the original particle, thisiiaking or dissevering being considerably facilitated if the particles are moistened.
The pieces of impurities, however, when subjected to a shearing, crushing orimpact blow are disintegrated "into fragments which are 'of"a general spherical or cubical nature and have comparatively all of their dimensions the same.
If the particles of vermiculite and impurities are disintegrated to pass through slotted openings which are just sufiiciently-wide to permit .the.pas sage of the vermiculite flakes edgewise by the shortest dimension, and then passed "over a square-opening screen, the widest ldimensions of which are equal to, or preferably larger than, the width of the slot, then a separation or segregation of the flake-like vermiculite from the cube-like impurities take place. The vermiculite flakes, scales or plates, because of their much greater lengththan their width, will be caught and retained on, the screen while the impurities,
having all dimensions more or less the same, and one of whichis suiiici'ently short to pass the slot; will pass through thescreen, and, in practice, it has been found'thatthe jagged inequalities of the impure particlesfwill necessitate the inside dimension of the square openings of thescreen being appreciablyflarger, about 70% to 90%.
thanthe width or thefslbt; The vermiculite that may have passed through 'the. square screen with the impurities can be recovered by'subsequent aidedby the-fact that they'do ,not disintegrate as quickly-as the vermiculite.
To enable. those a'cquaintedwith this art to fullyunderstandthe present invention and the several advantages and benefits accruing from its adoption a present preferred machine embodiment of theinvention has been illustrated in the accompanying drawingsforming a part of this specification and to which reference should be had in connection withthe following detailed description, and, for simplicity, like reference numerals have been employed throughout the several views of the drawings to designate the same. parts.
In these drawings:--
Figure 1 is a substantially-central, longitudinal, vertical section through the apparatus, with parts more or less broken away;
Figure 2 is an elevation of the right-hand end of the appliance;
Figure 3 is a vertical cross-section on line 3-3 l of Figure 1;
Figure 4 .is an enlarged, fragmentary cross section through the lower portion of the multiple revolving drum, showing the three types of screens, used, and illustrating also one of the several cylindrical grindingerods; and Figure 5 is a fragmentary cross-section through the middleslotted drum on a still larger scale.
This apparatus comprises an inclined, multiple, revolving drum or trommel, characterized as a whole ll, having around its periphery three, concentric drums l2, l3, and H, the inner one of which is formed of a number of longitudinal,
parallel, solid, wear-resisting, metal bars l5, l5 which are of the shape in cross-section shown in Figure 4 and which indicates that one side of each of these bars is formed so that any material not sufl'icientlp reduced in sizewill be carried up to the top of 'the drum and then dropped down.
In the present preferred embodiment of the invention these bars [5, l5 are spaced apart three-quarters of an inch at their closest points which 'is'sufilciently far apart to permit the properly-reduced material within the drum to pass to the second orgnextouter drum. As is fully shown,
the spaces between these bars enlarge downward- 1y or outwardly and the spaces are at an angle to 'the'correspon'ding radius of the drum, whereby any material which can pass through the narrowest inner portions of such slots will encounter -no substantial restriction therebelow.
- This inner drumor grating accommodates a number of loose, solid-metal grinding-rods l6, is of substantially the length of the drum and bearing on its inner surface, these grinding-rods during the rotation of the drum assuming positions somewhat analogousto those indicated in Figure 3, such rods acting during the revolution of the drum to provide a shearing action on the particles (if-vermiculite substantially parallel to the planes of the flakes of which they are made 'ii ana also to apply a grinding force to the parti'cles of impurities.
The second or next outer drum I3 comprises a slotted grill made up of a large number of parallel rods ll, 11 of the shape in cross-section as shown in Figure 5, being somewhat of inverted -V -shape o'n'top with narrow slots l8 between their upper portions, the spaces I9 outwardly be 'yond such narrow slots diverging or flaring outwardly as is fully depicted; whereby the crosssection of these metal bars l1 forming the slots l8- l9 is such as to prevent binding of the vermiculite' fiakes which tend to pass therethrough,
these screens belngsoldin the trade under the name Rima.
The width of each slot 18 in the present device is .04 inch and such slots may beof any length greater than one-half inch.
It is also possible to use slots formed by perforated metal plates for this drum, and in general the greater the percentage of openings, the greater the capacity of the drum, but the area of openings must be balanced against wear and service.
The outer drum l4 consists of a woven-wire metal-screen having openings 0.078 inch square.
These several drums are mounted in the relation stated by any convenient structural means, the triple drum being supported for rotation in any appropriate manner, as by resting on flanged rollers 2i cooperating with end rings 22 of the multiple drum resting upon them.
At one end the compound drum is provided with a ring-gear 23 in mesh with a driving-pinion 24 on the shaft of reduction-gearing 25 driven by an electric-motor 26, all of these features being of the usual type for revolving drums.
At its more elevated end the drum is closed by a wall 21 through which an inclined chute 28 extends a slight distance into the drum and the other, or lower, end of the drum is closed by a wall 29 through an opening in which an inclined, reciprocating, slotted screen, characterized as a whole 3|, extends.
As is shown in Figure 3, that portion of this screen 3| inside of the multiple drum has flaring or diverging side- walls 32, 32, the screen itself being divided into two parts, upper and lower, 33 and 34, respectively, each screen section being composed of parallel bars spaced apart, those of the section 33 having slots one-half inch wide, while those in the section 34 are one-quarter inch wide.
The duplex -or multiple screen-3| is supported and guided in its inclined relation'by a plurality of rollers 35, 35 andis vibrated back and'iorth by a power-driven eccentric 36 connected to the underside of the delivery chute 31 of the screen by a connecting-rod 38, there being nothing novel in the particular mechanism for actuating this screen. a
The rotary, multiple drum |2-'-|3--|4 is housed in a casing 39 through the opposite end walls of which'the chute 28 and the screen 3| project, such casing having a bottom 4| converging downwardly to a central discharge-pipe 42 through which the material passing through the outer of the three screens passes, such pipe being connected to a side-flue 43 joined to a combustiontube 44 equipped with an oil-burner45, fine 43, having damper-equipped openings or vents 46 by means of which the amount oi entering outer air may be readily regulated to control the temperature of the drying gases constituting the products of combustion from the burner.
As will be readily understood,"the hot gases flow through conduits 44, 43, 42 into the main housing or shell 38, and after properly drying the contents of the revolving screens pass out through the chute 28.
At its lower end the appliance has a chute 41 for the discharge therethrough of the cleaned, sized vermiculite which is delivered thereto in any approved manner from the outer screen |4 through the meshes of which it does not pass.
Assuming that the multiple-screen |2-|3-|4 is rotating at an appropriate speed, that the vibratory or reciprocatory screen 3| is working, and that the hot gases are at a suitable temperature and flowing through the apparatus, the operation of the appliance is substantially as follows:
The impure ore as it comes from the mine is passed through a three-quarter-inch revolving grizzle to eliminate the larger pieces of impurities and it then enters the revolving multiple-drum through the inclined chute 28.
In the innermost of the three drums, the lumps or conglomerates of impurities and vermiculite are shattered, the larger pieces or boo of vermiculite are flaked, and the bigger pieces of impurities are broken up or disintegrated by the action of the metal grinding-rods IS.
The rotation of such inner drum and the more or less flightlike construction of the bars l5 which it is composed lift up the particles remaining in the drum and drop them onto the reciprocating screen 3|, which removes the larger impurities and permits the vermiculite and the smaller pieces of impurities to pass through and onto the grinding-rods again.
The slots of such vibrating screen are of such width. as to allow the vermiculite to pass therethrough edgewise, but the larger pieces of impurities are retained on the screen and are removed by sliding down the bars of which the screen is made and delivered at the outer end of the screen structure exterior to the drum housin or casing.
As has been indicated, the spacing of the reciprocating-screen bars is such that they are closer together the farther away from the entrance chute 28, because the vermiculite flakes are thinner and the impurities are smaller as they proceed down the screen due to their being subjected to more grinding action by the rods i6.
Flakes of vermiculite and particles of impurities that are of sufliciently small size pass through the openings .of the intermediate slotted screen l3 and onto-the square-opening screen l4.
Flakes thatare larger than .078 inch square in area will be retained on and delivered Irom screenl4, while all impurities and flakes that are under .078 inch ,will pass through such outer screen 'and be delivered through the conduit 42.
Practically all of the impurities will pass through the square-opening screen, 42 because they arev more or less round or cubical in shape, and those that have passed through the middle screen with its .04 inch slots will pass through the .078 inch square openings.
Only a few of the impuritiesare flatand are retained on the square-opening or flnal screen, whereas the vermiculite being iiat and thin will readily pass through the narrow slots of the middle screen, but those particles having an area greater than .078 inch will not pass through the square apertures of the outer screen.
The clean vermiculite passes through the exit 4l and the portion passing through the squareopening screen l4 drops through the duct 42 into another apparatus constructed according to the same principle but with different dimensions so as to operate on smaller sizes, or it is cleaned by other means that are adapted to act on small sizes of vermiculite ore.
Various modifications of the above process and apparatus in some instances can be used to advantage; for example, the mine-runore which has first passed through a three-quarter-inch grizzle to remove large-pieces can then be treated in an apparatus similar to that illustrated and described with the exception that no breaking or grinding rods l6 are employed and no vibratory screen 3| is used inside oi the drums, the purpose of such an apparatus being to separate the particles of impurities and vermiculite which are originally of a size that, would pass through the openings of the several drums, which action decreases the chance of these particles being unnecessarily disintegrated in the regular apparatus with the grinding-rods and it reduces operating costs by avoiding the necessity of turning over the rods for dsintegrating purposes when screening only is required. The employment of such a device also facilitates grinding of the impurities and flaking of the vermiculite in the regular apparatus, as there is no buffing effect due to the fines.
It is considered as a valuable part of this invention that vermiculite flakes can be split into thinner ones when subjected to a shearing force parallel to the planes of the flakes and that this splitting is greatly improved by moistening the vermiculite particles, and in this connection it is to be remembered that besides vermiculite, this principle can be applied to any cleaning problem in which flake-like particles are to be segregated from round or cubical particles of a friable nature.
As has been indicated, the larger pieces which do not as first pass through the inner drum, as well as those remaining on the middle. drum, are carried up by the rotation of the drums and dropped onto the reciprocating screen and those particles which pass through the latter drop onto the lower part of the inner drum and are again acted upon by the grinding-rods, this action occurring repeatedly if necessary.
are subject to modification without departure from the principles on which the invention is based.
I claim:
1. In an appliance for separating of the vermiculite group from its impuritiea the combination of a'rotary trornmel having three screen-drums one inside of the other, means to rotate said trommel,"means to introduce the impure 'ore .to be treated into the innermost of said screen-drums, said innermost screen-drum having slots approximately three-quarters ofan inch wide,.the intermediate screen-drum having slots approximately four one-hun'dredths of i an inch in width, the third outer 'screemdrum having substantially-square openings practically seventy-eight one-thousandths of an inch on a side, free elongated grinding-rodsin and lengthwise of said innermost drum to apply a shearing force to the vermiculite particles substantially parallel to the planes of the flakes of which they are composed to divide such particles into thinner particles and to break up the impurities into smaller pieces, an inclined reciprocatory screen insideof said trommel having a plurality of sections with difierent sizes 'of screen openings and located to receive the material carriedup by, and delivered to it by,the rotary trommel and to discharge the material which does not pass through the screen outside of said trommel, and means to deliver the segregated treated'vermiculite and the fragmerited impurities separately from the appliance.
2. In an apparatus for separating'amineral of the vermiculite'group from its impurities, the combination of a rotary'trommel having three screen-drums inside of and spaced from one another, said innermost screen-drum having longitudinal slots, said intermediate screen-drumhaving narrower longitudinal slots, said outer screendrum having apertures each with its two dimensions substantially equal, and with such dimension greater than the width of the slots in the intermediate screen-drum, means to rotate said trommel, means to introduce the impure ore to be treated into said innermost screen-drum, a plurality of free elongated grinding-rods in and disposed lengthwise of said innermost screendrum to apply shearing forces tothe vermiculite particles therein substantially parallel to the planes of cleavage of the flakes .0! which they a mineral The invention is defined by the appended are composed to divide such particles into thinner flakes and to break up the impurities into smaller pieces, means to deliver the vermiculite particles .which fail to pass through said outer screen-drum, and means to separately discharge the impurity particles which pass through said outer screen-drum.
3. The structure presented in claim 2 in combination with means to heat the material undergoing treatment in the appliance. I
4. The structure presentedin claim 2 in which the slotsin 'said'innermost screen-drum flare outwardly and are oblique to their corresponding radii 1 i 5. In an apparatusior-separating a mineral of the vermiculite group from its impurities, the combination ofa rotary trommel having three screendrums inside of and spaced from one another, said innermost screen-drum having longitudinal s1ots, said intermediate screen-drum having narrower longitudinal slots, said outer screen-drum having apertures each with its two dimensions substantiallyequal, means to rotate said trommel, means to introduce the impure ore to betreatedinto said innermost screen-drum, a reciprocatoryscreen inside of said innermost screen-drum to receive the material carried up by, and dropped into it during the rotation of,
the 'trommel and to deliver its portion retained on the screen outside of the trommel, a plurality of free elongated grinding-rods in and disposed lengthwise of said innermost screen-drum to apply shearing forces to the vermiculite particles therein substantially parallel to the planes of cleavage of the flakes of which they are composed to dividesuch particles into thinner flakes and to break up the impurities into smaller pieces, means to deliver the vermiculite particles which fail to pass through said outer screen drum,
andmeans to separately discharge the impurity particles which pass through said outer screendrurn.
6. The structure presented in claim 5 in which the reciprocatory. screen is inclined and has a plurality of sections with different sizes of screen openings.
7. The structure presented in claim 1, in which the slots of said innermost screen-drum flare outwardly and are oblique to their corresponding radii.
RICHARD ERICSON.
US72530A 1936-04-03 1936-04-03 Vermiculite ore treatment Expired - Lifetime US2139358A (en)

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2465632A (en) * 1947-04-08 1949-03-29 Paul P Burns Tumble barrel
US2868735A (en) * 1955-07-08 1959-01-13 Zonolite Company Method of processing vermiculite
US3614002A (en) * 1969-07-07 1971-10-19 D Ore Mills Inc Dry fine crusher
US4065060A (en) * 1976-10-06 1977-12-27 Aluminum Company Of America Metal flake production
US5340558A (en) * 1993-06-14 1994-08-23 W.R. Grace & Co.-Conn. Vermiculite composition with improved thermal expansion properties

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2465632A (en) * 1947-04-08 1949-03-29 Paul P Burns Tumble barrel
US2868735A (en) * 1955-07-08 1959-01-13 Zonolite Company Method of processing vermiculite
US3614002A (en) * 1969-07-07 1971-10-19 D Ore Mills Inc Dry fine crusher
US4065060A (en) * 1976-10-06 1977-12-27 Aluminum Company Of America Metal flake production
US5340558A (en) * 1993-06-14 1994-08-23 W.R. Grace & Co.-Conn. Vermiculite composition with improved thermal expansion properties

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