Improvements in or relating to Methods of and Apparatus for Purifying and Pulverizing Mica and Mica-ore.
Year: 1895

page_text: Date of Application, 22nd Oct., 1895-Accepted, 11th Jan., 1896
Improvements in or relating to Methods of and Apparatus for
Purifying and Pulverizing Mica and Mica-ore.
A communication from THOMAS JEFFERSON LOVETT, Manufacturer, of
4001 Diexel Boulevard, Chicago, Cook County, State of Illinois, United
States of America.
I, ALFRED JULIUS BOULT of 323 High Holborn in the County of Middlesex,
Chartered Patent Agent, do hereby declare the nature of this invention and in
what manner the same 1s to be performed, to be particularly described and
ascertained in and by the following statement
This invention relates to an improved method of producing from mica-ore
granular or pulverulent mica free from grit, and it also relates to improved
apparatus which is employed in carrying out the said method
The inherent lubricating properties of mica, its toughness and combustibility,
render it an exceedingly desirable ingredient for lubricating compounds; and
while this desirability has long beeu recognized, the difficulties hitherto existing
in the way of reducing the mica to the necessarily finely divided state and of
freeing it from all gritty substances have prevented its employment, to any great
extent, in the manufacture of axle-grease and other lubricating compounds for
general use. So far as my correspondent is aware the absence of a sufficiently
practical method of and appliances for reducing the mica and freeing it from gritty
substances, has not only made the matter of the production of pure and finely
divided mica slow and laborious, but has also inade it necessary to employ blocks
of mica practically free from grit instead of mica-ore, all of which rendered the
product too expensive to compete commercially with other lubricating compounds.
The object of this invention is to provide an improved method of treating
mica-ore, especially that of low grade carrying other and gritty minerals in more
or less large proportion and also to provide apparatus for cariying out the method,
whereby ore may be treated in large quantities and the mica separated, practically,
from every particle of grit and reduced to the desired degree of fineness, all in a
manner which renders the product practically inexpensive and desirable for its
purpose.
In canying out this improved method the mica-ore is fed into a machine which
acts upon the mica to the extent of reducing it to flakes or scales comprising
lamin so thin that no gritty material will exist between its surfaces, and upon the
gritty minerals to the extent of reducing them to a powder or at least to a more
finely divided state than the mica. The mass reduced as described is then
subjected to a separating operation, which causes every particle of gritty mineral
substance to be eliminated from the mass of mica flakes and the latter to be left
in a practically pure state. The flaked and purified mica is then fed to a
pulverizing machine, which reduces the flaky mass to a more or less pulverulent
state. From the pulverizer the mass may be, and preferably 18, passed to a
separating or sorting apparatus where the mica scales of different degrees of
fineness are sorted out and deposited in different receptacles.
In order that this improved method may be successfully carried out on a com-
mercial scale, special aud improved machines and apparatus have been devised, the
equivalents of which, so far as their operation upon mica-ore and mica are concerned,
do not exist, so far as my correspondent is aware, in the same or any other art.
It

page_text: being necessary to protect the mica when freed from the gritty constituents of the
ore, if it is to be used as an ingredient of a high class lubricating compound,
from access thereto of any gritty material, such as dust carried by the atmosphore,
it is desirable that the process of disintegrating the ore, climinating the grit, and
then pulverizing the mica, be carried on in one continuous operation and that the
apparatus be inclosed.
In the drawings-
Figure 1 is sectional view in the nature of a diagram showing a building fitted
with apparatus of the improved construction for carrying out this improved
inetliod;
Figure 2, a broken and enlarged section of the initial or mica-flaking machine,
the section being taken on line 2 of Figure 3;
Figure 3, a section taken ou line 3 of Figure 2;
Figue 4, a broken elevation of separating apparatus for ficcing the mica flakes
from the gritty material,
Figures 5, 6 and 7 and 74, broken sections taken respectively, on lines 5, 6 and 7
of Figure 4 and viewed as indicated by the arrows;
Figure 8, a section taken on line 8 of Figure 9 and showing the mica pulverizer;
and
Figure 9, a section taken on line 9 of Figure 8.
A is a building having a lower apartment or chamber A' and upper apartments
o chambers AA. B is a chute o hopper which empties upon a chute B
leading to the mica-flaking machine C Dis the discharge-pipe of the inica-
flaking machine, interposed in which is a fan or blower D¹. The pipe D
communicates with initial separating apparatus located in the apartment A³ and
communicating with secondary separating mechanism F located in the apartment A³.
The separating mechanism F discharges into a bin or lopper G, from the lower
end of which extends a pipe G¹ leading to the mica-flaking machine H. Extending
from the machine H is a discharge-pipe I provided with a fan or blower I¹ and
leading to a settling-device K which is divided internally into sorting chambers.
Owing to the peculiarly soft and tough characteristics of mica it presents much
greater resistance to disintegration under impact, abrasion or attrition than the
more buttle nunerals present in mica-ote It has been found in practice that to
successfully reduce mica from lumps or sheets to a flaky state it is necessary to
provide a machine in which the moving parts shall have a cutting and tearing
effect upon the lumps or sheets in addition to the pounding and grinding effect
produced by beateis and the abrasion of particles against each other. The
Haking-machine C aets upon the mica in the manner stated and upon the other
and more bittle minerals in a manner to reduce them to fine powder
The machine C compuses a shell containing a chamber C₁ formed with side-walls
o cheeks and a base-wall rounded in the direction of the length of the
machine, as indicated in Figure 2 Mounted in bearings on opposito sides of
the machine and extending through openings in the cheeks into the chamber C
nie separate rotary shafts so provided with pulleys s³. On the inner ends of the
shafts are vertical disk heads provided with annular concentric series of
disintegrating fingers, the fingers upon the two disks being mutually inter-
side at one end of the
currents, as indicated in the figuies. At the ups. Extending across the
chamber C is an inlet spout to which the chute Bi
chute at the spout 3 is a rotary shaft r provided with radial plates. At the top
and center of the chamber C is the outlet pipe D, and below the said ontlet is a
Bсleen D'.
S
The pulleys are belted to a pulley on a drive-shaft Z in a manner to cause the
shafts to rotate in opposite directions. The fan D' is also belted to the drive-
shaft In practice it is preferred to rotate the disks at a speed approximating
1200 revolutions per minute, and the disks are preferably so adjusted with relation
to each other that the fingers nearly but not quite intermesh. Mica ore in lumps
sufficiently small to pass between the shaft and base of the chute are fed from
g

page_text: the bin or hopper B down the chute B' and passed into the chamber C¹ by the
rotating feed-plates r. As the ore drops between the disks s³ the action of the
fingers, which are angular and preferably square in cross section, is to tear and
cut the lumps of inien one by repeated engagement therewith, and reduce the mica
portion to a flaky mass, and the other and more gitty minerals to a powder. The
strong air curients produced by the rotating disks and their fingers tend to keep
the lumps between the disks until they are properly reduced, and as the lighter
flakes and other particles are driven to the upper part of the chamber, they pass
though the sureen Dand are diawn through the pipe D by the suction action
of the fan D', whence they pass to the separating apparatus next to be described.
It is found in practice that in the reduction of mica to flakes not exceeding, say,
one-quarter inch aica m the manner descubed, the separated lamina are so thin
that no foreign and gritty particles will exist between the surfaces, and substantially
all the gritty mineral will be so reduced that its largest particles will be smaller
than the smallest mica flakes. The screen D2, which regulates the size of flakes
which may be discharged from the machine, is therefore made with a mesh
preferably of about one-quarter inch. Constructed as described the machine is
capable of treating the ore in the manner stated very quickly, thus giving it great
capacity; and as the disks and fingers and other impact surfaces are formed of
haidened steel. the machine is very durable.
The pipe D extends to the ceiling of the apartinent A², and is provided at the
top in its forward side with an outlet opening leading to a compartment E' closed
at the back by a wall g' and the sides of the walls q2 and fitted at its forward side
with an inclined screen E2. Extending between the pipe D on one side and the
opposite wall of the compartment E' is an inclined shelf q3 and a diaphragm q',
the shelf being toward the lower part of the compartment, and the diaphragm q
extending from a short distance above the shelf nearly but not quite to the top of
the compartment and inclined preferably to an angle between the vertical plane
aud that of the scicen E. The screen at its lower edge is secured to a cross-piece
or clent g³, and the lower end of the compartment between the cleat q and wall q
18 open to afford an outlet 9. Hinged to the cleat q and extending through the
wall g to the apartment A³ is the fiame E³ of a screen or sieve E', which is
inclined in the downward direction from the cleat , the frame resting at its
opposite end portion upon an agitator E. The frame E³ is provided with side-
bars p and a top-plate p, the latter extending short of the upper end of the frame
to afford an opening p². The 11ame is open at its lower end portion to afford an
outlet p³. Extending from the upper edge of the plate p' to the wall q² above the
opening p is a flexible covering p, which renders the passage from the compart-
ment E to the screen E' close. Extending below the screen E is a stationary
and inclined base E provided toward its lower end with an outlet p³ leading to a
pipe p which extends back to the apartment A2. Interposed in the pipe p³ is a
fan p' which is diven by a pulley belted to a line shaft Z. Fastened to the
edges of the base E and around the screen E are a strip or strips of flexible
material forming sides p' and giving to the device the function of a bellows. The
agitator E provided, comprises a shaft n carrying cam fingers or wipers n' and
driven by a pulley ³ belted to the drive shaft Z In the rotation of the shaft n
the cams 'cause the lower end of the screen to 11se and fall, thus giving an up and
down shaking motion to the screen.
In the operation of the separating apparatus the air-currents from the fan D¹
euter the compartment E through the opening g and stule the screen E. The
shelf q and diaphragm g' causes the an-current as it enters the compartment to
whirl around the diaphragm through the openings above and below the latter and
strike the screen several times before it spends itself by passing through. The
screen E should have a mesh smaller than the smallest size fakes of mica, but
larger than the largest size particles of grit, whereby as the current is driven more
or less repeatedly against the screen, the gritty particles will pass through and
cause no material waste of the mica. The air current will spend its force entirely

page_text: by passing through the screen E so that the mica flakes will fall down the
screen E' below the shelf g, and drop through the discharge opening onto the
screen E. The screen E is of a mesh approximating that of the screen E and
as the mass falls upon the screen E the agitation given to the latter causes it to
slide and roll down through the spout p³ to the bin or hopper G. Any particles
of gritty minerals which have escaped separation from the mica in the initial
separator, will, as the mass rolls down the screen E, drop through onto the
base E, whence it runs to the pipe and is carried by the fan p' back to the
apartment A' The suction action at the opening p tends in the practice to atd
the progress of the flakes from the initial separator through the secondary
separator to the bin G, and the bellows action tends to keep the screen E' from
becoming clogged. After the flakes have passed through the initial and secondary
separator, they will be freed entirely fiom gut and be sufficiently pure for use in a
lubricating compound, while all the gutty material will have been deposited in the
apartment A³.
Extending from the bin or hopper G is a pipe G³ having a horizontal section G
leading to the mica pulverizer II. In the pipe of passage G² and extending
longitudinally thereof is a shaft G3 provided with a spiral blade or screw G.
The shaft G³ caries a pulley and is belted, as indicated.in Figure 1, to the line-
shaft Z'.
To reduce mica fiom a flaky state to powder in the quantities and at the
necessary speed for the purpose, it must be subjected to a peculiar tearing and
cutting operation differing radically from the operation of machines employed in
pulverizing any other material of which my correspondent is aware.
The pulverizer H comprises a shell or casing closed on all sides, except at the
outlets hereafter mentioned, and having side-walls or cheeks m. Extending across
the lower part of the shell and journaled in bearings m' at the sides of the cheeks
are parallel shafts 1. The shafts occupy the relative positions shown in the
diawings and are provided with pulleys . Keyed to the shafts and intermeshing
with each other are series of disks held in place at proper distance liom each
other on the shafts by means of spacing collars . The disks are circum-
ferentially seated, the teeth being set to project alternately from opposite sides
of the disk, as shown in the bgures. The base m³ 18 rounded under each set of
disks, as indicated in Figure 8, to extend close to but out of contact with then
peripheries. Extending across the chamber, preferably at an angle from one side
to the other, as shown in Figure 8, 1s a screen 1, and two outlets are provided
above the screen, one, m³, at the top of the chamber and the other m', above the
lower end of the screen I. Extending across the chamber and Journaled in the
cheeks m above the screen 12 is a rotary shaft & carrying a flexible beater A.
The shaft carries a pulley 3, which may be belted as shown in Figure 1 to the
shaft Z. The inlet to the pulverizer chamber is at m³.
In operation the pulleys are belted to the shaft Z to rotate the shafts
opposite directions and at a very high speed. The woim feed G3 18 10tated to move
the mass of flaky mica, fed from the bin G, with desired speed and in desired
quantity to the feed opening m of the pulverizer. The current produced by the
1otating disks draw the material from the feed opening between the disks, whereby
it is acted upon by the teeth and reduced in a comparatively short tune to
powder. In the pipe G₁ and preferably at is an opening for the inward passage
of air which flows through the pulverizer chamber and screen [2 to the outlets m³ m²,
being drawn through the sections 13 1 of the pipe I by the action of the fan I'
The sci cen 12 is of very fine mesh which will only allow the mica to pass through
it in a pondered or more or less finely gianulated state. As fast as the mica is
reduced it is drawn through the screen by the air current and through the
outlets mm. The shaft & causes the flexible beater to slap the screen with
each revolution and thus tend to free it from any adhering particles of mica and
prevent its becoming clogged. The muca after, being reduced is forced by the
fan 1 through the pipe I to the settling-device K which will be next.described..
'

page_text: The settling device is provided with a series of hopper-shaped bases i 22 23
having valved outlets In the device at opposite sides of the said bases are
partitions extending upward nearly to the top of the chamber afforded by the
casing; and intermediate of the said partitions are downward extending partitions/
wh.h extend from the top of the chamber downward as indicated, the partitions
act as baffle-walls, causing the client entering from the pipe to take the course
indicated by the arrows to the outlet g. The baile-walls tend to precipitate the
particles of mica into the hoppers out of the path of the current, and as a con-
sequence of the arrangement shown, the counsel and heavier particles tend to fall
into the hopper, those of the finer grade into the hopper ', those of a still finer
grade into the hopper, and those still finer into the hopper, while any particles
cared though the outlet g will be in the form of flom or impalpable powder too
light for separation from the moving curi cut In order to save this impalpable
powder, which is the finest grade, and most valuable for certain lubricating com-
pounds, to the outlet g is attached the mouth of a bag on "balloon "of material
sufficiently porous to permit the passage through it of air but too fine to allow the
mica to pass though to any great extent. The bag or balloon may be open at
its lower end and there fastened over a receptacle
In the manufacture of lubricating compounds of different grades or for different
purposes mica of different grades of fincuess is desuable. By means of the settling
and sorting device K described, mica of five grades of fineness, 18 obtained the
giades being separated. Under each hopper a receptacle e may be provided and
these receptacles may be in the form of batiels or casks, as shown, in which the
various grades may be stored until wanted for use.
Having now particularly described and ascertained the nature of the said inven-
tion as communicated to me by my foreign correspondent and in what manner
the same is to be performed, I declare that what I claim is
-
1. The method of reducing mica-bearing ore to obtain therefrom, in a pure and
finely divided condition, its contained mica, which consists in first disintegrating
the ore by subjecting it to the action of 10taly beaters until the mica is reduced to
thm flakes and the gritty constituents of the one are reduced to a degree of fineness
greater than that of the mica, and are completely detached therefiom, then through
the medium of an air-blast subjecting the disintegrated mass to the action of
sifting-mechanism thereby separating the fine gritty constituents from the larger
mica flakes, whereby only the pure mica is intercepted, and finally reducing the
resultant pure mica to the desued finely divided condition, substantially as
described.
2. Apparatus for the reduction of mica-ore to obtain therefrom its contained mica
in a pure and finely divided state, comprising in combination, a mica flaking device
consisting of a shell having a close chamber provided with a feed opening and a
discharge opening, shafts extending into the chamber from opposite sides thereof,
disks on the shafts, fingers of the disks angular in cross-section to present cutting
edges, a screen between the disks and discharge opening, means for rotating the
shafts at high speed in opposite directions, whereby the ore entering through the
feed opening is engaged by the fingers and disintegrated until the mica is i i educed
to thin flakes and the more brittle gritty constituents are reduced to a degree of
fineness greater than the mica, a conduit extending from the said discharge opening,
air blast mechanism in the conduit, a separating chamber at the end of said conduit
provided with a screen serving to sift through its mesh the finer gutty constituents
impelled against it by the air-blast from the larger nuca flakes whereby only the
puie mica is intercepted, a discharge conduit foi said separating chamber, a mica
pulverizing device to which said conduit leads comprising a close chamber having
a discharge outlet, a rotary pulverizer in the chamber, and a screen between the
said pulverizer and outlet, a settling device and a conduit provided with air-blast
mechanism and extending from the pulverizing device outlet to the settling device,

page_text: all constructed and arranged to operate substantially as and for the purpose set
forth.
3. The combination with a machine for treating mica-ore to reduce the mica to
flakes and the gritty constituents to a state of greater fineness than the mica flakes,
of apparatus for separating the mica from the gritty material, comprising a com-
partment closed at one side with a screen formed with a mesh which will niest the
flakes and permit the grit to pass through, an an-blast conveyor for feeding the mass
of reduced ore to the separating apparatus, opening into the said compartment, a
diaphragm in the compartment having a passage around it to produce a whil of
the current from the conveyor and thus tend to cally the mass repeatedly against
the screen, and an outlet for the mica flake, substantially as described.
4. The combination with a machine for tienting mica-ore to reduce the mica to
Hakes and the gritty constituents to a state of gienter hueness than the mica flakes,
of apparatus for separating the mica from the gritty material, comprising a com.-
partment closed at one side with a screen formed with a mesh which will arrest
the flakes and permit the gut to pass through, an an-blast conveyor, for feeding
the mass of reduced ore to the separating appaiatus, opening into the said compart-
ment, a diaphragm in the compartment having a passage around it to produce a
whirl of the curient from the conveyor and thus tend to carry the mass repeatedly
against the screen, a deflecting shelf below the sand diaphragm, and an outlet
passage for the mica between the said shelf and screen, substantially as described.
5 The combination with a machine for ticating mica ore to reduce the mica
to flakes and the gritty constituents to a state of greater fineness than the mica
flakes, of apparatus for separating the mira from the gritty material, comprising a
compartment closed at one side with a screen formed with a mesh which will arrest
the Hakes and permit the gut to pass through, an air-blast conveyor, for feeding
the mass of reduced one to the separating apparatus, opening into the said com-
partment, a diaphragm in the compartment having a passage around it to produco
a whirl of the current from the conveyor and thus tend to carry the mass
repeatedly against the screen, an outlet for the mica at the lower end of said
compartment, an inclined screen extending from said outlet, and means for agitating
the same, substantially as and for the purpose set forth.
6. The combination with a machine for treating mica-oie to reduce the inica to
fakes and the gritty constituents to a state of greater fineness than the mica flakes,
of apparatus for separating the mica from the gritty material, comprising a com-
partment closed at one side with a screen formed with a mesh which will arrest the
flakes and permit the grit to pass through, an an-blast conveyor for feeding the
mass of reduced ore to the separating apparatus, opening into the said compartment,
a diaphragm in the compartment having a passage around it to produce a whirl of
the current from the conveyor and thus tend to carry the mass repeatedly against
the screen, an outlet for the mica at the lower end of said compartment, an inclined
frame Ebinged at its higher end at said outlet, having a close top p p and
Bides p³, a screen E in its base, and an outlet pat its lower end, means for
oscillating the frame on its hinge, and a base E below the screen having close
bellows sides connected with the sides of said frame, all constructed to operate
substantially as and for the purpose set forth.
Dated this 22nd day of October 1895.
BOULT & WADE,
Agents for the Applicant.