Abstrict The present invention pertains to a system and a method for recovering
salvageable ferrous and non-ferrous materials from incinerated waste
materials including friable, carbonaceous incineration byproducts
such as ash and associated ferrous and non-ferrous metal components.
The system includes at least one crushing means for selectively
comminuting friable material comprised of a rotating roll having
at least one protrusion, preferably a weld extending transversely
to the direction of rotation of roll, on its exterior cylindrical
surfaces in spaced relation to a backing plate. The backing plate
is urged toward the roll by a bias means exerted a preferably adjustable
pressure sufficient to comminute the friable carbonaceous material
to a desired size, and insufficient so as to permit the backing
plate to retract and allow passage of ferrous and non-ferrous components
in the waste material through the crushing means substantially uncomminuted.
The bias means tends to rapidly urge the retracted backing plate
to its set position and exert a selective comminution pressure through
the retraction cycle. At last a first separating means coacts with
the first crushing means for at least partially separating comminuted
carbonaceous incineration byproducts from ferrous and non-ferrous
metal components; and first magnetic means separates ferrous metal
components from the waste material. The present invention further
relates to a novel crusher for selectively comminuting friable materials
without substantially comminuting associated malleable materials.
Claims What is claimed is:
1. A system for recovering salvageable ferrous and non-ferrous
materials from incinerated waste material including carbonaceous
incineration byproducts such as ash and associated ferrous and non-ferrous
metal components, comprising:
a. first conveying means for conveying incinerated waste materials
to a first selective crushing means;
b. first crushing means for comminuting selectively carbonaceous
incineration byproducts without substantially comminuting associated
ferrous and non-ferrous metal components by passing said waste material
between a rotating roll and a backing plate, said roll having at
least one protrusion on exterior cylindrical surfaces thereof to
enable passage of said waste material through said crushing means,
and said backing plate forming a throat with said roll shaped such
that the backing plate exerts concentrated pressure on waste material
on passage thereof through the throat between the backing plate
and the roll and said backing plate urged toward the roll by a bias
means exerting a pressure sufficient to comminute carbonaceous incineration
byproducts in the waste material to a desired size and insufficient
so as to permit the backing plate to retract and allow passage of
ferrous and non-ferrous metal components in the waste material through
the crushing means substantially uncomminuted;
c. first separating means coacting with said first crushing means
for at least partially separating based on size comminuted carbonaceous
incineration byproducts from associated ferrous and non-ferrous
metal components in the waste material;
d. first magnetic means for separating ferrous metal components
from the selectively comminuted incinerated waste material; and
e. collection stations for collecting separated comminuted carbonaceous
incineration byproducts, separated ferrous metal components, and
remaining waste material including nonferrous metal components.
2. A system for recovering salvageable ferrous and non-ferrous
materials from incinerated waste material including carbonaceous
incineration byproducts such as ash and associated ferrous and non-ferrous
metal components as claimed in claim 1 wherein the selective comminution
pressure exerted by the bias means of the first crushing means is
maintained during retraction of the backing plate.
3. A system for recovering salvageable ferrous and non-ferrous
materials from incinerated waste material including carbonaceous
incineration byproducts such as ash and associated ferrous and non-ferrous
metal components as claimed in claim 1 wherein the pressure exerted
by the bias means of the first crushing means is adjustable to accommodate
for variability in comminution hardness of carbonaceous material
in the waste material.
4. A system for recovering salvageable ferrous and non-ferrous
materials from incinerated waste material including carbonaceous
incineration byproducts such as ash and associated ferrous and non-ferrous
metal components as claimed in claim 1 wherein each protrusion on
the roll of the first crushing means is a weld extending along the
exterior surface transverse to the direction of rotation of the
roll.
5. A system for recovering salvageable ferrous and non-ferrous
materials from incinerated waste material including carbonaceous
incineration byproducts and associated ferrous and non-ferrous metal
components as claimed in claim 1 wherein the first separating means
comprises a means for orienting comminuted material discharged from
the first crushing means so as to present flat and elongated surfaces
in the waste material to the separating means and facilitate separation
of the comminuted carbonaceous byproducts from the waste material
including ferrous and non-ferrous components.
6. A system for recovering salvageable ferrous and non-ferrous
materials from incinerated waste material including carbonaceous
incineration byproducts such as ash and associated ferrous and non-ferrous
metal components as claimed in claim 1 further comprising:
f. second conveying means for conveying processed incinerated waste
material from the first separating means to a second selective crushing
means;
g. second crushing means for further comminuting selectively carbonaceous
incineration byproducts without substantially comminuting associated
ferrous and non-ferrous metal components by passing said waste material
between a rotating roll and a backing plate, said roll having at
least one protrusion on exterior cylindrical surfaces thereof to
enable passage of the waste material through the second crushing
means, and said backing plate forming a throat with said roll shaped
such that the backing plate exerts concentrated pressure on waste
material on passage thereof through the throat between the backing
plate and the roll and said backing plate urged toward the roll
by a bias means exerting a pressure sufficient to comminute carbonaceous
incineration byproducts in the waste material to a desired size
and insufficient so as to permit the backing plate to retract and
allow passage of ferrous and non-ferrous metal components from the
second crushing means substantially uncomminuted; and
h. second separating means coacting with said second crushing means
for at least partially separating based on size comminuted carbonaceous
incineration byproducts from associated ferrous and non-ferrous
metal components in the waste material.
7. The system for recovering salvageable ferrous and non-ferrous
material from incinerated waste material including carbonaceous
incineration byproducts such as ash and associated ferrous and non-ferrous
metal components as claimed in claim 6 wherein the bias means of
the first and second crushing means allows the backing plates to
retract and allow passage of ferrous and nonferrous metal components
associated with carbonaceous incineration byproducts at a pressure
sufficient to comminute carbonaceous incineration byproducts to
particles about 11/2 inches and less in diameter.
8. The system for recovering salvageable ferrous and non-ferrous
material from incinerated waste material including carbonaceous
incineration byproducts such as ash and associated ferrous and non-ferrous
metal components as claimed in claim 6 wherein the bias means of
the first and second crushing means allows the backing plates to
retract and allow passage of ferrous and nonferrous components associated
with carbonaceous incinerated byproducts at a pressure sufficient
to comminute carbonaceous incineration byproducts to particles about
3/4 inch and less in diameter.
9. A system for recovering salvageable ferrous and non-ferrous
materials from incinerated waste material including carbonaceous
incineration byproducts such as ash and associated ferrous and non-ferrous
metal components as claimed in claim 6 wherein each protrusion on
the roll of the first and second crushing means is a weld extending
along the exterior surface transverse to the direction of rotation
of the roll.
10. A system for recovering salvageable ferrous and non-ferrous
materials from incinerated waste materials including carbonaceous
incineration byproducts such as ash and associated ferrous and non-ferrous
metal components as claimed in claim 1 further comprising:
f. a preliminary separating means prior to said first crushing
means to separate noncarbonaceous materials from the incinerated
waste material; and
g. a preliminary magnetic means for separating ferrous metal components
from the waste material prior to said first crushing means.
11. A system for recovering salvageable ferrous and non-ferrous
materials from incinerated waste materials including carbonaceous
incineration byproducts such as ash and associated ferrous and non-ferrous
metal components as claimed in claim 1 wherein said bias means of
the first crushing means allows the backing plate to retract and
allow passage of ferrous and non-ferrous metal components substantially
uncomminuted at a pressure sufficient to comminute carbonaceous
incineration byproducts to particles about 11/2 inches and less
in diameter.
12. A system for recovering salvageable ferrous and non-ferrous
material from incinerated waste material including carbonaceous
incineration byproducts such as ash and associated ferrous and non-ferrous
metal components as claimed in claim 1 wherein said bias means of
the first crushing means allows the backing plate to retract and
permit passage of ferrous and non-ferrous metal components substantially
uncomminuted at a pressure sufficient to comminute carbonaceous
incineration byproducts to particles about 3/4 inch and less in
diameter.
13. A method for recovering salvageable ferrous and non-ferrous
materials from incinerated waste materials including carbonaceous
incineration byproducts such as ash and associated ferrous and non-ferrous
metal components, comprising:
a. feeding incinerated waste materials to a selective first crushing
means;
b. comminuting selectively carbonaceous incineration byproducts
to a desired size in said first crushing means without substantially
comminuting associated ferrous and non-ferrous metal components
by passing said waste material between a rotating roll having at
least one protrusion on exterior surfaces thereof facilitating passage
of said waste material and a backing plate urged toward said roll
at a select pressure sufficient to comminute carbonaceous incineration
byproducts in the waste material to a desired size and insufficient
so as to permit the backing plate to retract and allow passage of
associated ferrous and non-ferrous metal components in the waste
material;
c. at least partially separating based on size the comminuted carbonaceous
byproducts from associated comminuted waste material including ferrous
and non-ferrous metal components; and
d. magnetically separating ferrous metal components from the comminuted
waste material.
14. A method for recovering salvageable ferrous and non-ferrous
materials from incinerated waste materials including carbonaceous
incineration byproducts such as ash and associated ferrous and non-ferrous
metal components as claimed in claim 13 wherein carbonaceous incineration
byproducts are comminuted in said first crushing means to particles
about 11/2 inches and less in diameter while avoiding substantial
comminution of associated ferrous and non-ferrous metal components.
15. A method for recovering salvageable ferrous and non-ferrous
materials from incinerated waste materials including carbonaceous
incineration byproducts such as ash and associated ferrous and non-ferrous
metal components as claimed in claim 13 wherein carbonaceous incineration
byproducts are comminuted in said first crushing means to particles
about 3/4 inch and less in diameter while avoiding substantial comminution
of associated ferrous and non-ferrous metal components.
16. A method for recovering salvageable ferrous and non-ferrous
materials from incinerated waste materials including carbonaceous
incineration byproducts such as ash and associated ferrous and non-ferrous
metal components as claimed in claim 13 wherein prior to separating
as described in step c the comminuted waste material is oriented
so as to present flat and elongated surfaces in the waste material
to facilitate separation of carbonaceous material from the comminuted
waste material including ferrous and non-ferrous metal components.
17. A selective crusher for selectively comminuting a friable material
without substantially comminuting a malleable material associated
with the friable material, comprising:
a. at least one roll rotatably mounted and having a generally cylindrical
exterior surface;
b. a backing plate movably positioned in spaced relation to each
roll and providing passage therebetween of friable material desired
to be comminuted along with associated malleable material desired
not to be comminuted, said backing plate forming a throat with said
roll shaped such that the backing plate exerts concentrated pressure
on waste material on passage thereof through the throat between
the backing plate and the roll;
c. at least one protrusion on the exterior surface of each roll
such as to enable passage of the friable material and associated
malleable material between the roller and backing plate; and
d. a bias means for urging each backing plate into spaced relation
with the exterior surface of a roll at a select pressure sufficient
to comminute friable material to a desired size between the roll
and backing plate and insufficient so as to permit the backing plate
to retract when malleable material enters between the roll and backing
plate to allow passage substantially uncomminuted malleable material
associated with friable material between the roll and backing plate,
and for returning such backing plate rapidly to said spaced relation
with the roll after the malleable material has passed between the
roll and backing plate.
18. A selective crusher as claimed in claim 17 wherein selective
comminution pressure is maintained by the bias means during retraction
of the backing plate.
19. A selective crusher as claimed in claim 17 wherein the pressure
exerted by the bias means is adjustable to accommodate for variability
in comminution hardness of carbonaceous material in the waste material.
20. A selective crusher claimed in claim 17 wherein the backing
plate is two or more independently operating segments so that the
passage of a large piece of malleable material is permitted in one
segment separately from the selective comminution is another segment.
21. A selective crusher as claimed in claim 17 wherein two rolls
are positioned substantially parallel array, and a backing plate
and a bias means are associated with each roll.
22. A selective crusher claimed in claim 17 wherein friable material
is comminuted to particles about 11/2 inches and less in diameter
while avoiding substantial comminution of associated malleable materials.
23. A selective crusher claimed in claim 17 wherein friable material
is comminuted to particles about 3/4 inch and less in diameter while
avoiding substantial comminution of associated malleable materials.
24. A selective crusher claimed in claim 17 wherein each protrusion
is a weld extend along the exterior surface of the roller transverse
to the direction of rotation of the roll.
25. The selective crusher described in claim 17 wherein the bias
means is comprised of air pressure cylinders.
26. The selective crusher described in claim 17 wherein the bias
means is comprised of hydraulic gas cylinders.
Description FIELD OF THE INVENTION
The present invention relates in general to a system and method
for recovery of salvageable materials from refuse, and specifically
to a system and method for the efficient and economical recovery
of ferrous and non-ferrous metal components from incinerated waste
materials. The present invention further relates to a selective
crusher suitable for use in the system and method.
BACKGROUND OF THE INVENTION
Recovery of Salvageable Metal:
In recent years, there has been a dramatic increase in the volume
and variety of solid waste products requiring disposal by both the
private and public sectors. Such solid waste products have in the
past been burned in open incinerators. However, due to current environmental
laws and regulations, open incineration of solid waste has been
restricted to a significant extent in many geographic areas and
in fact is prohibited in many urban areas today.
Disposal and burial of solid waste products in sanitary landfills
is a frequently used alternative disposal method. However, many
existing landfills are reaching their capacity and additional replacement
clean landfills have not been approved by regulatory agencies and
authorities due to existing environmental laws and regulations and
due to an actual shortage of land in some geographic areas.
Recovery of salvageable and recyclable metals, of course, reduces
the maount of waste products that must be disposed. Apparatus and
methods for recovery of salvageable and recyclable components, such
as glass, plastics, non-ferrous and ferrous materials, from solid
waste products are known in the prior art, e.g., U.S. Pat. Nos.
3086718; 3549092; 3659396; 3687062; 3788568; 3790091;
3885744; 3973736; 4020992; 4044956; 4070278; 4083774;
4337900; 4341353; 4362276; and 4387019. Such recovery apparatus
and methods proposed recovery of ferrous and non-ferrous metal components
from solid waste products both prior to and subsequent to incineration
of the solid waste products. However, ferrous and non-ferrous metal
components are generally not efficiently or economically recovered
by such prior art apparatus and methods.
Particularly, the systems and means for recovering non-ferrous
materials that have been proposed to date for separation of non-ferrous
metal from incinerated solid waste and ferrous waste components
are expensive to build, expensive to operate and resulted in low
percentage of recovery of non-ferrous metals. It has been proposed
to indiscriminately comminute the non-ferrous metals, along with
the ferrous metals and other materials in the incinerated solid
waste, and then separate the non-ferrous metal by a float-sink method.
Alternatively, it has been proposed to comminute the incinerated
solid waste in a cage mill and then separate the non-ferrous metal
in a two-stage trommel screen. These methods have been discontinued,
however, because of the low efficiency in recovery of non-ferrous
metals and the high costs of assembly and operation of the equipment
and system.
In addition, the quality of the recovered ferrous and non-ferrous
products varies widely due to the incinerated waste product carryover
(called "tramp"), and the extreme variability of the moisture
content (typically 20 to 75%) in both the pre-incinerated and incinerated
waste material.
A need thus exists for a system that will permit efficient and
economic recovery of ferrous metal, such as iron and steel, and
non-ferrous metal, such as aluminum, from incinerated waste materials
including friable carbonaceous incineration byproducts, such as
ash. Such a system, should not only permit the recovery of the salvageable
ferrous and non-ferrous metal components with relatively low percentage
of tramp, but also should reduce the amount of the incineration
byproduct, e.g., ash and metal, that must be disposed by conventional
disposal such as landfill. As to the latter, the present system
allows for reclaim of carbonaceous incineration byproducts for use
as ballast for road beds and the like, in addition to efficient
and economical recovery of ferrous and nonferrous metals.
Crusher Devices:
Various types of devices for crushing and communication have been
known for decades. These include hammermills, cage mills, attritors,
ball mills and rod mills. These devices have been used to crush
and comminute a whole myraid of materials from rock, coal, ores
and solid waste to chocolate and paint pigment.
U.S. Pat. No. 2582734 discloses one such crusher which has relation
as prior art to the presently claimed subject matter. A horizontal
roll crusher is disclosed that has a main eccentric gyrated crusher
drum positioned between the crushing plate surfaces of a pair of
swing jaws. Each swing jaw is supported and resiliently carried
by springs and hydraulic shock absorbers. These bias means are designed
primarily to provide the function of protecting the swing jaws and
the other parts of the crusher against excessive mechanical overload,
as well as secondarily to serve the additional function of accurately
positioning the swing jaws in accordance with the relative wear
of crusher surfaces and in accordance with the desired finest of
the crushed product to be produced by the crusher.
Another example of a similar prior art crusher is disclosed in
U.S. Pat. No. 1783373. A single-roll crusher is disclosed that
has a breaker-plate mounted to crush coal, ore and the like in the
throat between the breaker plate and the single roll. The improvement
there described is a breaker plate in a plurality of sections hanging
from a single shaft, each section of which is independently supported
and postioned in alignment with the crusher roll. The breaker-plate
is urged toward the crusher roll by bias means that permit relief
to avoid breakage and cracking when foreign objects, such as large
pieces of wood, tramp iron and the like, are delivered to the crusher
along with the coal, ore or other material to be crushed. The purpose
of the bias means is to avoid breaking or cracking of the backer-plate
or crusher roll by "a large foreign body, incapable of being
crushed," thereby avoiding the condition that would require
stoppage of the crusher and dismantling the machine until a new
backer-plate or roll could be supplied.
In these prior art crushers, the bias means avoided damage to the
machine upon the encounter of the rare, foreign body that was incapable
of being crushed. There is no suggestion that the bias means exert
such pressure so as to selectively comminute certain materials within
a mix of materials while allowing associated materials to remain
substantially uncomminuted. To the contrary, the pressure exerted
by the bias means is purposely set very high so as to indiscriminately
comminute all of the materials encountered except for those few
pieces incapable of being crushed, where breaking or cracking the
machine would result. Also, there is no suggestion in these prior
art crushers of regulating the pressure exerted by the bias means
to allow efficient comminution of select materials within a mix
while avoiding comminution, to the extent possible, of associated
materials within the material fed to the crusher.
STATEMENT OF THE INVENTION
The present invention pertains to a system for recovering salvageable
ferrous and non-ferrous metals from incinerated waste materials,
including friable carbonaceous incineration byproducts such as ash
and associated ferrous and non-ferrous metal components. The invention
comprises first conveying means for conveying incinerated waste
material to a first selective crushing means; first selective crushing
means for substantially comminuting carbonaceous incineration byproducts
while avoiding substantial comminution to associated ferrous and
non-ferrous metal components; first separating means coacting with
said first crushing means for separating at least in part comminuted
carbonaceous incineration byproducts from the waste material; first
magnetic means for separating at least in part ferrous metal components
from non-ferrous metal components in the selectively comminuted
waste material; and collection stations for collecting separated
comminuted carbonaceous incineration byproducts, separated ferrous
components and remaining waste material containing non-ferrous components.
The first selective crushing means is comprised of a rotatably
mounted roll and a backing plate positioned in juxtaposition to
the roll to form a throat through which material to be comminuted
may pass. The throat is shaped such that the backing plate exerts
concentrated pressure on waste material on passage thereof through
the throat between the backing plate and the roll. The rotating
roll has at least one protrusion, preferably a weld, on the exterior
cylindrical surfaces thereof facilitating passage of waste material,
or other similar material to be comminuted, through the throat.
The backing plate is urged toward the roll by a bias means exerting
a pressure sufficient to comminute carbonaceous incinerated products
in the waste material in the throat, and insufficient so as to permit
the backing plate to retract and allow passage of associated ferrous
and non-ferrous metal components in the waste material through the
crushing means substantially uncomminuted. In this regard, some
comminution of the ferrous and non-ferrous metal components may
be tolerated to permit efficient comminution of carbonaceous byproducts.
For this reason, preferably the bias means is capable of regulating
the pressure exerted on the waste material and is capable of maintaining
the pressure during retraction of the backing plate.
Additionally, the first separating means is preferably comprised
of a means for orienting comminuted material discharged from the
first crushing means so as to tend to present flat and elongated
surfaces to the separating means in such way that elongated and
flat metallic material tends to be retained by the separating means,
thereby enhancing the separation of carbonaceous components from
the ferrous and non-ferrous metal components.
In a more preferred embodiment, the system further comprises second
selective crushing means for further selectively comminuting carbonaceous
incineration byproducts while avoiding substantial comminution of
associated ferrous and non-ferrous metal components; and second
separating means coacting with the second crushing means for selectively
separating at least in part additional comminuted carbonaceous incineration
byproducts from ferrous and non-ferrous metal components. In addition,
second conveying means are preferably provided for conveying waste
material with ferrous and non-ferrous metal components to the second
crushing means, and a third conveying means for conveying the separated
solid waste containing ferrous and non-ferrous metal components
from the second separating means to the first magnetic means.
In an even more preferred embodiment, the system further comprises,
prior to said first selective crushing means, a preliminary magnetic
means for separating ferrous metal components from the incinerated
waste material and a preliminary separating means for separating
non-carbonaceous materials other than ferrous and non-ferrous metal
components, such as glass, sand and dirt, from the incinerated waste
materials. By these preliminary means, the quantity of carbonaceous
byproducts and ferrous metal components in the waste material can
be reduced to allow for more efficient recovery of the ferrous and
non-ferrous metal components in the system.
The present invention further relates to a method for recovery
of ferrous and non-ferrous metal components from incinerated waste
materials using the system of the present invention; and to a novel
selective crusher, as described generally above, for selectively
comminuting friable carbonaceous materials while avoiding substantial
comminution of associated malleable materials. The selective crusher
is suitable for applications other than the recovery system and
method of the present invention.
Other details, objects and advantages of the invention will become
apparent as the following description of the presently preferred
embodiments and presently preferred methods of practicing the invention
proceeds.
BRIEF DESCRIPTION OF THE DRAWINGS
In the accompanying drawings, the preferred embodiments of the
invention and preferred methods of practicing the invention are
illustrated in which:
FIG. 1 is a process schematic diagram of a preferred embodiment
of the recovery system of the present invention;
FIG. 2 is a plan view of an embodiment of a preferred selective
crusher employed in the present invention;
FIG. 3 is a cross-sectional view taken through line A--A of the
preferred selective crusher described in FIG. 2;
FIG. 4 is a cross-sectional view taken along the line A--A of an
alternative preferred selective crusher of the present invention;
FIG. 5 is a cross-sectional view taken along line A--A of another
alternative preferred selective crusher of the present invention;
FIG. 6 is a process schematic of an alternative preferred embodiment
of the recovery system of the present invention;
FIG. 7 is a plan view of an alternative preferred selective crusher
employed in the present invention;
FIG. 8 is a cross-sectional view taken through line A--A of the
alternative preferred selective crusher described in FIG. 7; and
FIG. 9 is a cross-sectional view taken along line A--A of still
another alternative preferred selective crusher of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
The present invention is directed to a system for recovering salvageable
ferrous and non-ferrous materials from incinerated waste materials
including friable carbonaceous incineration byproducts such as ash,
and associated ferrous and non-ferrous metal components. The invention
is comprised of a first conveying means for conveying incinerated
waste materials to a first selective crushing means; first selective
crushing means for selectively comminuting carbonaceous incineration
byproducts without comminuting, to the extent possible, associated
ferrous and non-ferrous metal components; first separating means
coacting with said first crushing means for separating at least
in part comminuted carbonaceous incineration byproducts from the
ferrous and non-ferrous metal components; and first magnetic means
for separating at least in part ferrous metal components from the
selectively comminuted waste material; and collection stations for
collecting separated comminuted carbonaceous incineration byproducts,
ferrous metal components, and remaining waste material including
non-ferrous metal components. The first magentic means preferably
removes ferrous components from the waste material after selective
comminution and after separation of carbonaceous byproducts for
efficient operation.
The feed material processed in the recovery system generally consists
of the bottoms remaining after incineration of waste materials,
and preferably the bottoms produced in a mass or shredded burning
operation used to generate electricity from municipal waste. The
bottoms product generally includes incinerated carbonaceous byproducts,
such as ash, and associated ferrous metals components, such as iron
and steel, and non-ferrous metal components, such as aluminum, copper,
nickel, silver, gold and brass. The bottoms product may also, include
glass, ceramics and other refuse, typically contained in municipal
refuse, that are not completely incinerated at the temperatures
attained in the furnace. Although incinerated waste materials are
the preferred feed stock of the invention, other feed materials
including ash and ash-related products with non-ferrous and/or ferrous
metal components are also suitable.
Referring to FIG. 1 the feed material is delivered to first selective
crushing means 4 in the recovery system of the invention preferably
by a first conveying means 3. First conveying means 3 may be a belt-type
conveyor at an angle from the horizontal. The system includes a
first separating means 5 receiving the selectively comminuted feed
material from first crushing means 4. Second conveying means 6
typically a belt-type conveyor or another conventional conveyor
similar to first conveying means 3 may also be provided for conveying
the remaining feed material from the first separating means 5.
Preferably the feed material, conveyed from an incineration plant
by conveying means 1 is also preliminarily processed before delivery
to first conveying means 3 by a preliminary separating means 2 to
remove a large amount of the carbonaceous ash component, such as
glass, said and dirt, and improve processing efficiency in the recovery
system. Also, preferably components greater than about four to ten
inches in size are removed by a grissly or trommel before the waste
material reaches the end of conveying means 1. Separating means
2 is preferably at a variable angle vibrating conveyor/screen separator
in order to regulate the variable flow of the waste material across
the screen/conveyor to enhance separation. The screen angle is preferably
between about 10 and 45 degrees from the horizontal, and most preferably
between 13 and 20 degrees, with the exact angle being selected to
maximixe the retention time of the material on the screen without
overloading the screen, and still maintaining operating efficiency
to the system. In addition, separating means 2 may be comprised
of a substantially flat, preferably solid plate 7 preferably about
2 to 3 feet in length and fastened to the separator means, onto
which the waste material is discharged from conveying means 1 so
that pieces in the waste material tend to be oriented to present
flat and elongated surfaces to the separating means in such way
that elongated and flat metallic material tends to be retained by
the separating means, thereby enhancing separation of the carbonaceous
components from the waste material by separating means 2. However,
solid plate 7 is not preferred on the preliminary separating means
where high quantities of waste material are to be processed at this
point in the system. Typically separating means 2 are a vibrating
conveyor, and generally remove one-third or more of the incinerated
waste material so as to reduce the quantity of feed material processed
through the system and in turn increase the efficiency of separation
of ferrous and non-ferrous materials from the carbonaceous material
during later stages of the system. The separated carbonaceous materials
deposited from separating means 2 on carbonaceous-removal conveyor
means 8 typically a flat belt conveyor, are conveyed to a sized-ash
collection station 9 for use, or returned to the incineration plant.
Also, a preliminary magnetic means 10 is preferably provided adjacent
first conveying means 3 for removal of large ferrous pieces, such
as iron and steel, from the waste material to reduce the quantity
of feed material delivered to first crushing means 4 and the other
parts of the recovery system, thereyb increasing the system's efficiency.
In a preferred embodiment of the invention, magnetic means 10 is
a transfer type magnetic head such as manufactured by Sterns Magnetics,
Inc. or Erie Magnetic, Inc. The ferrous material collected by preliminary
magnetic means 10 is deposited on ferrous-removal conveying means
11 typically a belt conveyor, from where it is conveyed to a ferrous
collection station 12. Ferrous collection station 12 may be the
same as that used for collection of ferrous components later in
the system, as shown in FIG. 1 or it may be a separate collection
station if desired.
First selective crushing means 4 is a novel crusher which selectively
comminutes friable carbonaceous incineration byproducts to a desired
particle size while avoiding, to the extent possible, substantial
comminution of associated ferrous or non-ferrous metal components.
Crushing means 4 is preferably a roll crusher 30 as shown in FIGS.
2 and 3 comprised of a roll 32 rotatably mounted on frame 33 by
conventional bearing means, and a backing plate 34 in juxtaposition
forming a throat with roll 32 through which incinerated waste material
to be selectively comminuted may pass. Roll 32 also has at least
one protrusion 31 that facilitates passage of the waste material
through the throat between roll 32 and backing plate 34. Protrusions
31 may be made of any suitable material such as bolts or rivets,
but they are preferably metal welds extending across the exterior
cylindrical surface of roll 32 transverse to the direction of rotation
of the roll. Protrusions 31 in the form of welds are easily formed
and replaced with breakage and wear. Protrusion 31 may extend across
the entire cylindrical surface of roll 32 or be in staggered on
nonstaggered segments. In addition, the welds forming protrusion
31 are preferably hard-faced welds made by welding metal strips
to the rolls and then hard facing using suitable welding rods. In
any event, the welds preferably provide straight edges perpendicular
to the direction of rotation of the roll for more efficient passage
of the waste material through crusher 30.
The size of protrusions 31 is preferably less than 5/8 inch in
height to avoid wear, and preferably about 1/8 to 1/4 inch in height
for efficiency of operation. Also, although one protrusion 31 may
be sufficient to provide for operation of crusher 30 preferably
at least two to six, and preferably two to four protrusions 31 are
provided transversely along the exterior cylindrical surface of
roll 32 for efficient operation of crusher 30. The number and spacing
of protrusions 31 will vary depending upon the desired efficiency
of operation of crusher 30 upon the diameter of roll 32 and the
composition of the waste material being processed. The diameter
of roll 32 may also vary depending upon the size of the pieces to
be comminuted and other design parameters: for comminution of coarser
material anticipated in common incinerated waste material, roll
32 may be 10 to 12 inches in diameter, although a smaller diameter,
e.g., 41/2 inches, is acceptable; and for comminution of smaller
particles of incinerated waste materials, smaller diameter roll
32 e.g., 41/2 inches, is more preferred.
Backing plate 34 is preferably substantially flat to exert concentrated
pressure on the waste material between the backing plate and roll,
and in turn provides more efficient selective comminution of the
carbonaceous material by crusher 30. The angle formed at the throat
between roll 32 and backing plate 34 is not particularly critical.
It should be sufficient so as to provide for efficient operation
of the crusher, and will depend to some degree upon the diameter
of roll 32. The angle selected involves a balancing of the efficiency
of processing with the efficiency of separation.
The spacing between roll 32 (at protrusions 31) and backing plate
34 in the throat is preferably slightly less than the desired maximum
size of the comminuted carbonaceous byproducts. For example, the
spacing would be about 1/2 inch for comminution of carbonaceous
material to about 3/4 inch in size, and about 1/8 to 3/8 inch for
comminution of carbonaceous material to about 1/2 inch in size.
The spacing between roll 32 and backing plate 34 is generally between
about 1/8 and 11/2 inches and preferably less than 1 inch and more
preferably less than about 1/2 to 1/4 inch for efficient selective
comminution of incinerated solid waste material. The precise spacing
for best results will depend upon the particular dimensions of the
crusher and the desired capacity of the system.
The incinerated waste materials are conveyed to selective crusher
30 by an inclined plate 35 forming a chute as part of frame 33
from where the material is delivered to the throat between rotating
roll 32 and backing plate 34. Chute 38 is also fastened on frame
33 to provide for the feed of waste material, with flexible flap
39 of reinforced rubber or the like contacting backing plate 34
to facilitate flow of waste material to the crusher. Roll 32 is
preferably driven with a low power electric motor, e.g., 5 to 25
pH., through a standard pulley and V-belt drive train at relatively
low rpm, e.g., 530 rpm and below.
Backing plate 34 is preferably pivotally attached on frame 33 by
bearing means 37 as shown in FIGS. 2 and 3. Backing plate 34 is
maintained in position by bias means 36 preferably air pressure
cylinders, gas hydraulic cylinders or air bags, which are preferably
pivotally mounted to frame 33 and to backing plate 34 as shown
in FIG. 3. Bias means 36 compresses when larger pieces of ferrous
or non-ferrous metal in the incinerated waste materials enter the
throat between rotating roll 32 and backing plate 34 and returns
rapidly upon passage of the metal component to comminute carbonaceous
byproducts in the waste material in the throat between roll 32 and
backing plate 34. Bias means 36 is set to exert a pressure sufficient
to comminute the carbonaceous incineration byproducts in the waste
material, and insufficient so as to permit backing plate 34 to retract
and allow passage through the crusher of the associated ferrous
and non-ferrous metal components substantially uncomminuted. Bias
means 36 also preferably exerts such pressure against backing plate
34 throughout its stroke from set position to maximum release position
to maintain the pressure for selective comminution. In a most preferred
embodiment, backing plate 34 is maintained in position by two controlled,
spaced-apart air or gas pressure cylinders comprising bias means
36 pivotally attached to the base of backing plate 34. For commonly
encountered incinerated waste material, bias means 36 are maintained
under an air or gas pressure of preferably 40.+-.10 psi and capable
of returning to position almost instantly when a piece of ferrous
or non-ferrous metallic component passes the throat between rotating
roll 32 and backing plate 34. The pressure exerted by bias means
36 is also adjustable to accommodate for variability of hardness
of the carbonaceous incineration byproducts encountered in the same
incineration processes from time to time, and from different incineration
processes. It should be observed in this connection that some comminution
of ferrous and non-ferrous metal components will occur in the crusher,
and more comminution of ferrous and non-ferrous metal components
may need to be tolerated where particularly hard carbonaceous material
is to be selectively comminuted. The pressure on bias means can
be adjusted to balance between efficient comminution of the carbonaceous
byproducts and avoidance of comminution of the ferrous and non-ferrous
components.
Alternatively, selective crushing means 4 may be provided as shown
in FIG. 4. That is, selective crusher 30' may be provided with roll
32' rotatably mounted on frame 33' by conventional bearing means,
with backing plate 34' pivotally mounted in spaced relation with
the roll to form a throat therebetween through which waste material
to be selectively comminuted may pass. Roll 32' is again suitably
powered by a conventional low power electric motor and V-belt and
pulley drive train, and roll 32' again has protrusions 31' as described
above facilitating passage of the waste material through the throat.
Backing plate 34' is preferably pivotally mounted by bearing means
37' and spaced from roll 32' as described above. Also, as described
above, backing plate 34' is maintained in place by air pressure
cylinders, gas hydraulic cylinders, air bags or other suitable bias
means 36' that are pivotally attached to frame 33' and to backing
plate 34'. Bias means 36', through backing plate 34', exerts a pressure
on the waste material in the throat sufficient to comminute carbonaceous
incinerated products in the waste material to a desired size and
insufficient so as to permit backing plate 34' to retract and allow
passage of the ferrous and non-ferrous metal components substantially
uncomminuted. The waste incinerated waste material is delivered
to crusher 30' from chute 38' through opening 40' in frame 33' and
by inclined plate 35' forming a chute as part of frame 33'. The
alternative selective crusher 30' illustrated in FIG. 4 is not the
most preferred mode contemplated for the selective crusher because
it does not take maximum advantage of gravity feed into the crusher.
Still another alternative embodiment of the selective crushing
means is illustrated in FIG. 5. Crusher 30" is comprised of
roll 32" rotatably mounted by conventional bearing means on
frame 33' and has protrusions 31" as described above on the
cylindrical exterior surfaces to facilitate passage of the waste
material to be selectively comminuted through the crusher. Again
roll 32" is preferably powered by a conventional low power
electric motor and V-belt and pulley drive train. Backing plate
34" in this embodiment is also a roll in spaced relation from
roll 32" forming a throat therebetween through which the waste
material to be selectively comminuted may pass. Backing plate 34"
in this embodiment is preferably a roll substantially larger than
roll 32", as illustrated in FIG. 5. Backing plate 34"
in this embodiment also preferably has protrusions 31" facilitating
passage of the waste material, preferably spaced so as to correspond
with protrusions 31" on roll 32" to provide a concentrated
force on the waste material passing through the crusher. Backing
plate 34" is preferably rotatably mounted by supporting its
pivot axis in a bushing, and maintained in place relative to roll
32" by air pressure cylinders, gas hydraulic cylinders, air
bags or other suitable bias means 36", as described above,
that are pivotally attached to frame 33" and to backing plate
34". By providing the appropriate pressure on bias means 36",
backing plate 34" thus retracts to permit passage of salvageable
ferrous and non-ferrous metal materials from the waste material
relatively uncomminuted while selectively comminuting carbonaceous
incinerated products in the waste material to a desired size in
the throat. As in other embodiments, the waste material is delivered
to crusher 30" by an inclined plate 35" forming a chute
as part of frame 33", and chute 38" supported on frame
33". Here, flexible flap 39" is provided to contact backing
plate 34" to facilitate flow of waste material into the crusher.
Referring again to FIG. 1 first separating means 5 which separates
carbonaceous incineration byproducts from the comminuted waste material,
may be a conventional separator such as a screen separator. Preferably,
first separating means 5 is a combination vibrating screen/conveyor
such as sold by Bonded Scale and Machine Co. Moreover, first separating
means 5 is preferably comprised of a substantially flat, preferably
solid plate 13 preferably two or three feet in length and fixed
to the separating means, onto which the comminuted waste material
is discharged from crushing means 4. Solid plate 13 tends to orient
the present flat and elongated surfaces of the waste material to
the separating means in such way that elongated and flat metallic
material tend to be retained by the separating means, thereby enhancing
separation of the ferrous and non-ferrous metal components from
the waste material by the separation means. More preferably, a variable
angle vibrating conveyor/screen separator is also used in order
to regulate the variable flow of the comminuted carbonaceous byproducts
and associated ferrous and non-ferrous metal components across the
screen/conveyor to enhance separation. The screen angle is preferably
between about 10 and 45 degrees from the horizontal, and more preferably
between about 13 and 20 degrees, with the exact angle being selected
to maximize the retention time of the material on the screen without
overloading the screen and still maintaining operating efficiency
of the system. The vibrating screen/conveyor has a plurality of
openings preferably between about 3/8 inch and 11/2 inches, and
most preferably about 3/4 inch in size, through which a portion
of the vibrated ash or other comminuted carbonaceous and metal incineration
byproduct generally less than about 3/8 inch to 11/2 inches in diameter,
and preferably 3/4 inch and less in diameter, passes to a collection
station positioned below the vibrating screen or conveyor therefrom.
The separated carbonaceous material is deposited from first separating
means onto conveying means 8 and from there conveyed to collection
station 9. Collection station 9 is a conventional transporting container
for transporting the separated carbonaceous incineration byproducts
to a landfill for disposal, or, preferably, upon comminution to
appropriate size less than, for example, 3/8 inch, transporting
for use as balast for road beds or the like. When the latter preferred
use for the carbonaceous material is desired, it may be appropriate
to separately convey and collect the carbonaceous material passing
through preliminary separating means 2 or to further comminute,
by conventional means, the carbonaceous material passing through
preliminary separating means 2 before it is deposited in collection
station 9.
In a most preferred embodiment of the invention, as illustrated
in FIG. 1 a second selective crushing means 14 and second separating
means 15 are part of the recovery system. Second conveying means
6 conveys waste material comprised of carbonaceous incineration
byproducts with associated ferrous and non-ferrous metal components
from the first separating means 5 to the second crushing means 14.
Second crushing means 14 is similar to the first crushing means
4 in arrangement and operation as described alternatively with reference
to FIGS. 2 3 and 4; second crushing means 5 further selectively
comminutes the carbonaceous incineration byproducts to a lesser
size of preferably between about 1/4 and 11/2 inches and less, and
most preferably 1/2 inch and less, without substantially comminuting
associated ferrous and nonferrous metal components of larger size.
For this reason, the spacing between the roll and backing plate
of crushing means 15 and the height and positioning of the protrusions
of crushing means 15 are different from first crushing means 4 to
provide for efficient operation. The comminuted ash and associated
ferrous and non-ferrous metal components from the second crushing
means 14 are conveyed by a third discharge conveying means 16 to
a first magnetic means 17 for separation of the ferrous metal components
from the non-ferrous metal components, such as aluminum. Third discharge
conveying means 16 may also be a conventional conveyor system such
as a belt conveyor.
Second separating means 15 which further separates at least part
of carbonaceous incineration byproducts from associated ferrous
and non-ferrous metal components, after comminution by second crushing
means 14 may again be a conventional separator such as a screen
separator. Most preferably, second separating means 15 is again
a combination variable angle vibrating screen/conveyor such as described
above for first separting means 5. As described above with reference
to first separation means 5 second separation means 15 is preferably
comprised of a substantially flat preferably solid plate 18 preferably
two or three feet in length and fixed to separating means 5 onto
which the comminuted waste material is discharged from second selective
crushing means 14. Solid plate 18 tends to orient pieces of metal
in the waste material to present flat and elongated surfaces to
the separating screen and thereby enhance separation of the carbonaceous
components from the waste material including the ferrous and non-ferrous
metal. Again, the screen angle is preferably between about 10 and
45 degrees from the horizontal, and most preferably between about
13 and 20 degrees, with the exact angle being selected to maximize
the retention time of the material on the screen without overloading
the screen. Similar to first separator means 5 the vibrating screen/conveyor
of second separator means 15 is preferably a combination separator
and conveying means having a plurality of openings, preferably between
about 3/8 and 11/2 inches in size, and most preferably about 3/4
inch in size, which passes a further portion of the vibrated ash
or other comminuted carbonaceous incineration byproduct preferably
less than about 3/4 to 1 inch in diameter. The separated carbonaceous
material is deposited from second separator means 15 onto carbonaceous-removal
conveying means 8 from which it is conveyed to collection station
9. The ferrous and nonferrous component, with an amount of tramp,
is conveyed by third discharge conveying means 16 to first magnetic
means 17.
The ferrous and non-ferrous metal components are separated in the
system by first magnetic means 17. Magnetic means 17 may be any
type of magnet which will separate the ferrous metal components,
such as iron and steel, from the non-ferrous metal components, such
as aluminum. In a preferred embodiment of the system, the magnet
is a magnetic drum head such as manufactured by Sterns Magnetics,
Inc. or Erie Magnetic, Inc. The ferrous metal components are held
by the magnet and released to discharge into a ferrous collection
station 12. The remaining waste material including non-ferrous metal
components are discharged into a separate non-ferrous collection
station 19 with the assistance of an appropriately positioned diverter
20. The salvaged ferrous and non-ferrous metal components may then
be sold for the recovered ferrous and non-ferrous metal values.
The present system provides for highly efficient recovery of ferrous
and non-ferrous metal components from incinerated waaste material.
With a two-stage selective crushing system as illustrated in FIG.
1 typically greater than 90%, and more typically more than 95%
and as high as 99%, and more, of the carbonaceous component of the
waste material has been selectively comminuted to the desired screen
size for separation. Typically, less than 10% and more generally
less than 5% of the ferrous metal component that has been separated
by use of the system is tramp, and typically less than 40% and more
generally about 25% of the remaining waste material including nonferrous
metal components discharged from the system are tramp.
It should also be observed that the selective crushing means 4
and 14 have other applications beside the system for recovering
salvageable ferrous and non-ferrous materials from incinerated waste
material as described above. For example, such selective crusher
means may be useful in processing foods, such as crushing the meat
of peaches or olives while leaving the pits substantially uncrushed.
An embodiment of the selective crushing means may also be used in
cleaning metals, e.g., in cleaning stainless steel, and in foundries
for removal of the sand from castings.
Still another alternative embodiment of the present system for
recovery of salvageable ferrous and non-ferrous metal components
from incinerated waste is illustrated by FIG. 6. The elements of
the system which correspond to those described with reference to
FIG. 1 have been given prime numbers corresponding to the parts
and elements described with reference to FIG. 1. Selective crushing
means 4' and 14' may be one of the alternative embodiments described
with reference to FIGS. 2 3 4 and 5 but is preferably an embodiment
as is described with reference to FIGS. 2 and 3. The difference
in this embodiment is primarily the addition of preliminary crushing
means 21 described in detail with reference to FIGS. 7 and 8 and
tandem crushing means 23 described in detail with reference to FIG.
9. Additional differences are the location of the preliminary magnetic
means 10' adjacent conveying means 1' from the incinerator plant,
ahead of the preliminary separating means 2' rather than at the
end of first conveying means 3 and just ahead of selective crushing
means 4' as shown in FIG. 1. This embodiment has the advantage of
removing the larger ferrous metal components from the waste material
at the very outset before even preliminary separation of the carbonaceous
material in the recovery system and higher efficiency in selective
comminution in crushing means 23 as described in more detail below.
In this embodiment, as in the embodiment described with reference
to FIG. 1 larger pieces of material greater than about four to
ten inches will be removed from the waste material, e.g., by a grissly
or trommel, before they reach the end of conveying means 1.
Referring to FIGS. 7 and 8 the selective crushing means 21 is
designed for heavy duty use in selectively comminuting relatively
large pieces of carbonaceous material in the incinerated waste material
while avoiding, to the extent possible, comminution of the associated
ferrous and non-ferrous metal components. The construction of selective
crushing means 21 is preferably substantially the same as that described
above with reference to FIGS. 2 and 3 except that backing plate
34"' is divided into segments so that each segment extends
only about half the length of roll 32"'. Typically, roll 32"'
would be four feet in length so that the segments of backing plate
34"' are preferably only two feet in length. Backing plate
34'" could similarly be provided in more than two segments
if desired. In addition, to allow for independent operation of the
segments of backing plate 34"', an additional brace 41 and
additional supports 42 are provided as part of frame 33'" for
pivotally mounting the segments of backing plate 34'" and a
divider 43 extends through the selective crushing means 21. The
roll 32'" is preferably larger in diameter, e.g., ten inches
in diameter, than rolls 32 32' or 32" of selective crushing
means 4 or 14 and three spaced-apart bias means 36'" are preferably
provide on each segment of backing plate 34'". Bias means 36'"
are pivotally mounted to backing plate 34'" nearer the end
thereof to provide better mechanical leverage for bias means 36"
to exert pressure on the waste material passing through the throat
of the crushing means. In addition, selective crushing means 21
preferably has a spacing between the roll 32'" and the backing
plates 34'" of about 11/4 inches (about 5/8 inch between the
backing plate 34'" and protrusions 31'" on roll 32"'),
and is powered by a larger horsepower electric motor, e.g., 50 pH.,
running at a slightly higher rpm, e.g., 660 rpm. Also preferably
protrusions 31'" are elongated and staggered as shown in FIG.
7 with ends of protrusions of the staggered arrays overlapping
each other. By this embodiment, backing plate 34'" can retract
in segments from roll 32'" when ferrous or non-ferrous metal
components pass through the throat between the roll and backing
plate, and, in turn, a high volume of waste material can be efficiently
selectively comminuted by crushing means 21.
Referring to FIG. 9 selective crushing means 22 is design for
a more efficient selective comminution by effectively doubling the
comminution capacity of the crusher. The construction of selective
crusher 23 is preferably substantially the same as that described
above with reference to FIG. 2 and 3 except with two rolls 32.sup.4
A and 32.sup.4 B positioned in substantially parallel array. Each
roll, 32.sup.4 A and 32.sup.4 B, has a backing plate 34.sup.4 A
and 34.sup.4 B positioned in space relation with the roll. The backing
plates are each pivotally mounted on frame 33 by bearing means 37.sup.4
B. Backing plates 34.sup.4 A and 34.sup.4 B are urged toward rolls
32.sup.4 A and 32.sup.4 B, respectively, by bias means 36.sup.4
A and 36.sup.4 B, which are pivotally mounted to the opposite sides
of frame 33.sup.4 and to backing plates 34.sup.4 A or 34.sup.4 B.
Again, as described above with reference to FIGS. 2 and 3 the bias
means 36.sup.4 A and 36.sup.4 B exert a pressure sufficient to comminute
incinerated carbonaceous byproducts in the waste material and insufficient
so as to allow the backing plates to retract and permit passage
of ferrous and non-ferrous components of the waste material through
the crushing means substantially uncomminuted. Again, the height
and positioning of the protrusions 31.sup.4 on rolls 34.sup.4 A
and 34.sup.4 B are as described above with reference to FIGS. 2
and 3. The inclined plate 35.sup.4 in this embodiment is V-shaped
so as to direct the flow of waste material to the throat formed
between each roll and the associated backing plate.
The third separating means 22 is essentially the same as that described
above with reference to the first and second separating means 5
and 15. However, a flat is not preferably provided onto which the
comminuted waste material is discharged from selective crushing
means 21 because of the added volume of waste material at this point
in the system. Typically in this embodiment, also the screen size
of third separating means 22 would be selected so as to allow pieces
of 1/2 inch or less of the waste material to pass through, and the
screen sizes for first and second separating means 5' and 15' would
be selected so as to allow passage of 3/8 inch pieces of waste material.
In this embodiment, as shown, the carbonaceous material passed by
third separating means 22 is collected on conveying means 8' from
where it is conveyed to collection station 9'. However, if it is
desired that the carbonaceous material collected from the system
at collection station 9' be of smaller size, e.g., 3/8 inch and
less, it may be preferable to collect separately waste material
passing through third separating means 22 by a different conveying
means and collection station. The embodiment illustrated by reference
to FIG. 6 has the advantages of processing larger quantities and
larger sized pieces of incinerated waste material more efficiently.
Although the invention has been described in detail in the foregoing
for the purpose of illustration, it is to be understood that such
detail is solely for that purpose and that variations can be made
therein by those skilled in the art without departing from the spirit
and scope of the invention as described by the following claims. |