Slurrying apparatus including grinding and separating means

According to the present invention there is provided slurrying apparatus comprising a rotatable drum arranged for rotation about its longitudinal axis and including a slurrying chamber portion so arranged that when the drum is rotated feed material passes from an inlet of the slurrying chamber portion to a discharge chamber portion of the drum in which slurry and fine particles are separated from coarser particles and are discharged separately, and rotation means for causing rotation of the drum.

BACKGROUND OF THE INVENTION 
This invention relates to slurrying apparatus suitable for slurrying a feed 
liquid and a solid such as the bituminous sand containing hydrocarbons 
that is currently being mined in the Athabasca area of Alberta, Canada. 
Hydrocarbons can conveniently be extracted from bituminous sand by 
techniques that utilize the special and possibly unique conditions 
existing in the sand. Although the interstices of the sand are largely 
filled with oil, the individual grains of sand are separated from the oil 
by a minute film of water. Because the water is in intimate contact with 
the sand grains and prevents the bitumen from adhering to the sand grains, 
bitumen and sand can be separated by tumbling with hot or even cold water 
and the thus separated bitumen treated by suitable hydrocarbon extraction 
processes. 
DESCRIPTION OF THE PRIOR ART 
Various tumbling apparatuses are known for comminuting and disintegrating 
materials utilizing a rotatable drum tumbler having internal means to 
pulverize, grind or treat raw material. 
For example, U.S. Pat. No. 634,254 discloses a drum separated into two 
sections by a screen. Material fed into the first section is "coarse" 
ground by the action of large diameter steel balls as the drum rotates and 
the reduced material then passes through the screen into the second 
chamber which contains steel balls of a smaller diameter which reduce the 
material to a fine degree. 
Further, U.S. Pat. No. 1,075,707 discloses a pulverizing mill comprising an 
inclined rotatable drum having a series of fixed steel rolls of various 
diameters extending the length of the drum and positioned such that a 
number of the rolls roll in contact with the inner surface of the drum, 
adjacent rolls being held out of contact with each other, a number of 
smaller diameter rolls being arranged to roll in contact with two of the 
first mentioned rolls, but being held out of contact with each other. 
Material passing through the drum is thereby crushed to a fine degree by 
this rolling action. 
In addition, U.S. Pat. No. 2,450,980 discloses a rotating drum scrubber for 
removing dirt from aggregates such as sand and gravel, the drum including 
a number of vanes, pitched with respect to the plane of rotation of the 
drum, to advance a slurry therethrough. High pressure water is continually 
flushed through the drum, and the vanes separate the aggregate into coarse 
and fine fractions which are discharged separately for further processing. 
BRIEF SUMMARY OF THE INVENTION 
According to the present invention there is provided slurrying apparatus 
comprising a rotatable drum arranged for rotation about its longitudinal 
axis and including a slurrying chamber portion so arranged that when the 
drum is rotated feed material passes from an inlet of the slurrying 
chamber portion to a discharge chamber portion of the drum in which slurry 
and fine particles are separated from coarser particles and are discharged 
separately, and rotation means for causing rotation of the drum. 
Such apparatus can be used, for example, for slurrying and tumbling bitumen 
sand with water so as to form a dispersion prior to separation of the 
hydrocarbons. In addition, the apparatus of the invention desirably serves 
to separate and subsequently extract from the slurry any foreign bodies 
that would otherwise complicate a subsequent hydrocarbon extraction 
process. 
Preferably, the material slurrying chamber portion is adapted to grind or 
pulverize material and is internally lined with a plurality of plate 
assemblies comprising scoops and comminuting bars, the bars forming a grid 
matrix spaced inwardly from the internal wall of the drum. A feed hopper 
is conveniently provided at the inlet end of the drum by which feed 
material may be introduced to the slurrying chamber portion. Material so 
fed is initially separated by the grid arrangement, the fine solids 
passing between the bars and the larger solids and foreign bodies 
remaining supported thereby. In preferred arrangements slurry lifting 
means and primary and secondary discharge chambers cooperate to effect the 
separate discharge of fine slurried solids, and foreign matter from the 
apparatus.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S) 
Referring to the drawings, the illustrated slurrying apparatus which, for 
simplicity, will be referred to hereafter as a "tumbler" comprises an 
elongate drum 10 which in this embodiment is divided into four chambers: 
material slurrying chamber 11; a slurry lifting chamber 12; a primary 
discharge chamber 13 and a secondary discharge chamber 14. The tumbler is 
preferably mounted for rotation about a plane that is slightly inclined 
with respect to the horizontal so as to initiate and assist the flow of 
material from inlet end 15 of the tumbler to the discharge end 16 thereof. 
It is envisaged that the angle of inclination will be in the region of 
1.degree.-5.degree., suitable means described below being provided to 
enable adjustment of this angle. As shown in FIGS. 1 and 3, the drum 10 is 
rotatably supported by a plurality of rubber tire wheel assemblies 17 each 
assembly including a drive wheel 18 and an idler wheel 19 and being 
arranged to cause rotation of the drum 10 in the direction indicated by 
arrows B. To prevent longitudinal movement of the rotating drum 10, a pair 
of guide wheels 20 are utilized which rotatably bear against a guide ring, 
or flange 21 of shell 22 of drum 10 as it rotates. 
Considering the internal configuration of drum 10, the components utilized 
in chamber 11 will now be described, reference being made to FIGS. 1, 4, 
7, 8 to 12 and 13. 
As best shown in FIG. 4, the internal surface of shell 22 is provided with 
a plurality of liner plate assemblies 23, one such assembly being shown in 
FIG. 7. Each assembly 23 comprises a base plate 24 adapted to be bolted to 
shell 22 by a number of bolts 25. Plate 24 is curved so as to conform with 
the curvature of shell 22. On each base plate 24 are positioned at least 
two spaced, axially extending arcuate scoops 26, the scoops being welded 
to plate 22 and positioned by supports 27 such that the open end of each 
scoop is directed in the direction of rotation of the drum. To complete 
the assembly 23, a plurality of comminuting bars 28 are attached, for 
example by welding, to the scoops 26 to extend transversally with respect 
to the assembly and form a grid. These bars 28, which in the industry are 
generally called "grizly bars", are intended to assist in slurrying, and 
two alternative preferred forms of such bars are shown in FIGS. 7 and 9 to 
12. A typical cross-section of such a bar 28 is shown in FIG. 8. It will 
be appreciated that either or both types of bars 28 may be utilized and 
need not necessarily be arranged as depicted in FIG. 4 or 7. To further 
assist flow of material through the drum 10, it is envisaged that these 
bars 28 may be set on various pitches ranging from negative to neutral to 
positive, to vary the rate of advance of material. Such variable 
orientation allows longer or shorter retention times of material to 
improve the attrition of, for example, lumps of ore in the feed solids. By 
causing the larger solids to be retained on the grid during rotation of 
the drum, such solids are subject to more attrition than the finer 
slurried solids which fall between the bars 28 and are carried within the 
space between adjacent scoops 26. Furthermore, it is preferred that 
successive rows of the assemblies are staggered relative to adjacent rows, 
as shown in FIGS. 1 and 13. Further, a plurality of loose grinding rods 29 
are provided in the area between the adjacent scoops 26 (FIG. 4) for 
grinding material present in such areas. 
Referring now to FIGS. 1, 5 and 5a, it can be seen that slurry lifting 
chamber 12 is an extension of chamber 11, but is not provided with liner 
plate assemblies 23. Chambers 11 and 12 are separated by a dividing wall 
31 that is provided with an opening 30 to permit material to pass from 
chamber 11 to chamber 12. The purpose of chamber 12 is simply to lift the 
slurried material, and any foreign matter, and cause same to be passed 
into the primary discharge chamber 13. To facilitate lifting, in this 
embodiment, a pair of lifter assemblies 32 are provided, each comprising a 
base plate 33 and a lifting element 34 which has a scoop-like 
configuration. The assemblies 32 are fixedly attached to a wall 35 which 
separates chambers 12 and 13, the elements 34 being angled towards a 
central circular orifice or opening 36 in wall 35, i.e. extending from the 
inner surface of shell 22, in a direction tangential to opening 36. 
As will be evident from FIG. 1, the primary discharge chamber 13 comprises 
a discharge screen 37 in the form of a circular cylinder, the screen 
including openings or mesh 37a of a predetermined size that permits only 
material of that size or less to pass therethrough. Chamber 13 opens onto 
the secondary discharge chamber 14 so that any particles retained by 
screen 37 pass from chamber 13 to chamber 14 and accumulate therein. 
Referring to FIGS. 1, 6 and 6a, chamber 14 is provided with a single 
material lifter 38 which may be of similar construction to the lifter 32 
of chamber 12, but in this embodiment comprises a framework of spaced 
apart rods or bars 39, the spacings between adjacent rods being greater 
than the openings 37a of the discharge screen 37 in chamber 13. Lifter 32 
is angularly positioned with respect to an opening 40a in an end wall 40 
at the outlet end of the chamber so as to cause material lifted by lifter 
38 to pass therethrough. 
Finally, the tumbler is provided with a material outlet 41 which in this 
embodiment is a substantially horizontal tubular structure having an 
internal discharge scroll, the spiral configuration of which assist in 
ejecting the material from the tumbler. 
The operation of the above described apparatus will now be discussed in 
connection with comminution and slurrying of bituminous sand. 
Mined bituminous sand is fed via a conveyer system 42 into the hopper 43 of 
chute 44 attached to the inlet end 15 of drum 10 (FIG. 2). Hot or cold 
water under pressure is introduced through nozzle 45, mounted axially of 
the drum 10, to convert the mined material into a slurry within chamber 
11. Total slurrying, as will be appreciated, may not be achieved in view 
of the constituency of the mined material, which will probably include 
unbroken pieces of ore, large rocks and stones which themselves may be 
coated with bitumen. As the mined material enters chamber 11, it will fall 
into bars 28, the larger pieces being supported by the bars, while the 
slurried material, including smaller ore pieces, will fall between the 
bars to be held initially in the area between adjacent scoops 26 and there 
to be further pulped by action of grinding rods 29. As the drum 10 
rotates, the scoops 26 mechanically lift the slurried sand and small 
pebbles and empty same back into the central portion of chamber 11 to 
impinge upon the larger rocks and pieces of ore that are themselves 
tumbling around on top of the bars 28. By virtue of the bar configuration, 
the larger pieces of ore and the rocks are scrubbed by the tumbling action 
and additional scrubbing and ablation of the material resting on the bars 
is caused by the impingement of the smaller stones falling from the 
scoops. By controlling the pitch and offset of the comminution bars, the 
rate of advance of rocks can be controlled, and selected sizes can be 
advanced or retreated as desired. 
In this manner, substantially all of the hydrocarbon deposit can be 
separated from the coarse ore. Eventually, the slurry and any remaining 
large rocks and stones still supported by the bars are deposited in 
chamber 12 and are lifted by lifters 32 into primary discharge chamber 13 
through opening 36. 
As will be evident, the slurry is rotated around chamber 13, and all 
slurried material, except the larger rocks and stones, will be discharged 
from chamber 13 in the direction of arrow C via the screen 37. The 
material thus removed is then passed for further processing to remove and 
subsequently upgrade the end product i.e. the hydrocarbons. 
Again, as will be evident, the larger rocks and stones which remain in 
chamber 13 pass to chamber 14, where they are lifted and subsequently 
enjected from the apparatus. 
As mentioned above, the inclination of drum 10 with respect to the 
horizontal is capable of adjustment to control the rate of flow of 
materials. In the present embodiment this can be readily achieved by 
moving the two wheel assemblies 17 nearest the inlet end of the apparatus 
towards or away from one another, i.e. increasing or decreasing angle x 
(FIG. 3). 
Apparatus according to the invention also has application in the 
comminution of oil shale. Oil shale differs from bituminous sand in that 
it is a compact rock of sedimentary origin which contains organic matter 
that yields oil and gas on distillation. Oil shale, like bituminous sand, 
is mined and then broken down prior to distillation, again by a tumbling 
or comminuting process. 
At the present time, the distillation process is only capable of handling 
coarse materials, all finely ground material is currently being 
stockpiled. While processes are available to handle the distillation of 
"fine" material, the cost is prohibitive. It will however be appreciated 
that modifications to the apparatus described herein could be made to 
utilize the tumbler for comminution of oil shale. 
It will also be obvious to those skilled in the art, that the apparatus 
according to the invention has applicability in any process which requires 
that mined mineral materials be pulverized and/or slurried to assist in 
the extraction of specific mineral elements.