Note: Descriptions are shown in the official language in which they were submitted.
~Z1073S
Technical Field
This invention relates to the reclaiming of
storage battery materials and more particularly to the
separation and recovery of the various components of
batteries, such as lead-acid batteries.
Back~round Art
While the invention is illustratively described in
relation to the recovery of components of lead-acid
batteries, as will be o~vious to those skilled in the
art, the improved method and apparatus can be readily
applied to the recovery of component materials of other
types of storage batteries.
As is well known, the main constituent materials
of conventional present day batteries include hard
~ubber, polypropylene, polyethylene, or other similar
materials forming the battery container. These
materials, in combinati~n with the materials forming
~`
lZ~)735
the vent plugs, spacers, separators, insulators, and wrapping,
are commonly referred to as nonmetallic, or polymeric, compo-
nents. The electrode grids and electrical connections between
the grids and external circuit are conventionally formed of
metal. These metal components, in combination with the electrode
active material which, in most cases, contains metal compounds,
are commonly referred to as metal-containing, or metallic, compo-
nents.
A further major constituent material of conventional bat-
teries is the electrolyte. Generally, in processing lead-acid
batteries, the electrolyte is removed before the battery recov-
ery processes are begun. In known prior art processes, after the
battery acid is removed, the remaining components are fed into an
impact or shredding mill to be shattered or shredded into small
pieces. Typically, the resulting heterogeneous battery scrap mix-
ture has been separated by numerous screening and other
mechanical or physical separation processes into nonmetallic and
metallic portions wherein the metallic portions include coarse
metallic pieces, fine particle-size metallic components which
consist essentially of lead oxides and lead sulfate, and pure
lead powder from the electrode fill, as described in U.S. Patent
No. ~,107,007, of Andreas F. Gaumann et al.
In another known process, such as disclosed in German Patent
Disclosure 28 56 330, published July 12, 1979, Inventors, M.
Okuda and K. Tomisaki, Diamond Engineering Co., Ltd., waste con-
taining le~d sulfate is contacted with an aqueous solution of an
alkaline substance which converts lead sulfate into a water
insoluble lead salt such as lead carbonate, and also forms a
water soluble sulfate such 2S sodium sulfate, as a by-product.
Thereafter, the water insoluble lead salt is prepared for roast-
ing reduction.
r~
1210735
Several problems have existed with these various
known recovery processes. Illustratively, before
~echanical processing of the scrap batteries can take
place, the electrolyte must be removed from the battery
to prevent corrosion of the machinery thereby in the
subsequent steps of the process.
Such removal of the electrolyte from the battery
in the conventionally employed dry mechanical process
involves a costly time-consuming and labor-intensive
operation.
Another problem arising in the known recovery
method has been the undesirable cross-contamination of
the various constituents of the battery due to
inefficient separation of the components. It is
desirable to separate the battery components into as
pure a form as possible for efficient recycling. The
substantial cross-contamination of the constituents in
the known recovery methods has effectively prevented
the economical obtaining of a useful recycle product.
Additionally, environmental regulations concerning
toxic metallic compound exposure to employees and
processing effluents present substantial problems
relative to the known recovery methods. The cost of
compliance with such regulations has made such recovery
economically impractical where such control is obtained
by using conventional processes with add-on systems.
Because of the depletion of petroleum resources,
the desirability of use of battery-powered electric
vehicles and the like is manifest. It is very
important that a battery reclamation apparatus and
process which is environmentally pollution-free be
developed. The present invention meets those stringent
environmental demands and produces reprocessable
7~S
battery component products with efEectively minimized detrimental
effect upon the environment.
Disclosure of Invention
Accordingly, it is an object of the present invention to pro-
vide a process for reclaiming whole storage batteries, includingthe electrolyte. A further object of the present invention is to provide a
wet mechanical reclamation process for reclaiming whole storage
batteries, which produces independent isolated streams of battery
constituen~s. In particularly preferred embodiments, several
streams of battery constituents such as electrode active
material, metal material, electrolyte material, and polymeric or
other nonmetallic material, ar~ produced.
A still further object is to provide a storage battery
reclaiming process which operates within both environmental and
work safety standards.
Another object is to provide a storage battery reclaiming
process which is easily adaptable to the various designs and
sizes of battery containers and the various metallic and nonmetal-
lic constituents comprising the storage batteries.
Still another object is to provide a storage batteryreclaiming apparatus and process which are inexpensive and sim-
ple to utilize.
In accordance with one embodiment of the present invention,
there is provided an apparatus suitable for separating higher
density and lower density feed material having a predetermined
nominal particle size, or larger particle and smaller particle
feed material having substantially the same material density, de-
rived ~rom the breaking of lead-acid batteries, comprising an
elutriation column having a circular horizontal cross-section, a
liquid manifold circumferentially disposed exteriorly to and in
liquid communication with the interior of the lower portion of
D
~21073S;
the column through a plurality of sized and spaced inlet ports
located in the lower column; the inlet ports being sized and
spaced to control the liquid introduced radially inwardly into
the column to produce a uniform ascending stream current having a
sustained and substantially constant velocity; and means for
introducing liquid to the liquid manifold; an overflow weir
located at the top of the column for discharging lower density or
smaller particle material and liquid from the column, a cylindri-
cal feed inlet chute concentrically disposed at the top of the
column and projecting into the upper portion of the column, and
discharge means at the bottom of the column for discharging the
higher density or larger particle material from the column.
In accordance with another embodiment of the present inven-
tion, there is provided an elutriation column apparatus for
separating higher density and lower density feed material derived
from the breaking of lead-acid batteries and having a
predetermined nominal particle size, the column comprising an
upper cylindrical section and a lower cylindrical section having
a smaller diameter than the upper section and concentrically
disposed thereto; the upper and lower sections joined by a
truncated conical transition section; the upper cylindrical
section terminating in a horizontal circumferential lip defining
an overflow weir; a vertically adiustable cylindrical material
f~ed inlet chute having support means and a circular horizontal
cross-section, concentrically disposed with and extending
downwardly into the upper cylindrical column section; a
collection collar attached circumferentially about the exterior
of the upper column section, having a sloped floor and exterior
walls e~tending vertically above the floor to collect and
3Q discharge liquid and low density overflow material discharged
from the overflow weir; discharge means disposed at
r~
~Z1073S
5a
the bottom of the column for discharging the higher density
material from the column, the discharge means comprising conveyor
means discharging the higher density material above the liquid
level in the column; a liquid manifold circumferentially disposed
exteriorally to and in liquid communication with the interior of
the lower portion of the column through a plurality of sized and
spaced inlet ports located in the lower column; the inlet ports
being si~ed and spaced to control the liquid introduced radi.ally
inwardl~ into the column to produce a uniform ascending stream
current having a sustained and substantially constant velocity;
and means for introducing liquid to the liquid manifold.
~ n accordance with a further embodiment of the present inven-
tion, there is provided an apparatus suitable for separating
solid feed material derived from broken lead-acid storage batter-
ies, into a less dense material fraction and a higher densitymaterial fraction comprising a liquid elutriation column having a
ratio of column length to effective diameter of not greater than
6 to 1, and a uniformly distributed ascendiny liquid stream intro-
duced into the column through a liquid manifold in liquid communi-
cation with the lower portion of the column, the stream having alinear flow velocity through the column of about 50 feet per
minute and a liquid flow rate between approximately 450 and 500
gallons per minute through the column.
A still further embodiment of the present invention pro-
vides an elutriation column for separating feed material derivedfrom broken lead-acid storage batteries into a less dense
mate.rial fraction and a higher density material fraction wherein
the column CGmpriSeS an upper cylindrical portion and a lower
cylindrical portion concentrically joined thereto; means for
feeding material to ana discharging material from the column; the
column having a ratio of column length to effective diameter of
not greater than 6 to 1, and a uniformly distributed ascending
liquid stream introduced into the column through a liquid
manifold in liquid communication with the lower portion of the
column, the stream having a linear flow
D
12~0~3S
5b
velocity through the column of about 50 feet per minute and a
liquid flow rate between approximately 450 and 500 gallons per
minute through the column.
~et another embodiment of the present invention provides a
method for separating less dense material from heavier density
material, or smaller particle material from larger particle
material, derived from the breaking of lead-acid batteries, com-
prising the steps of:
(a) providing a feed material for a liquid elutriation
column wherein the material comprises a less dense material and a
heavier density material, or a smaller particle material and a
larger particle material, the feed material having a
predetermined maximum solid fragment size;
(b) providing a liquid elutriation column having a circular
horizontal cross-section, a liquid manifold circumferentially
disposed exteriorly to and in liquid communication with the
interior of the lower portion of the column through a plurality
of sized and spaced inlet ports located in the lower column; the
inlet ports being sized and spaced to control the liquid
introduced radially inwardly into the column to produce a uniform
ascending stream current having a sustained and substantially
constant velocity; and means for introducing liquid to the liquid
manifold; an overflow weir located at the top of the column for
discharging lower density material and liquid or smaller particle
material and liquid, from the column, a cylindrical feed inlet
chute concentrically disposed at the top of the column and
projecting into the upper portion of the column, and discharge
means at the bottom of the column for discharging the higher
density or larger particle material from the column;
(c~ introducing a liquid uniformly through the inlet ports
into the lower portion of the column circumferentially about th~
column;
(d) forming a uniform ascending liquid stream in the
column;
D
~IZ~073S
5c
(e) feeding the feed material into the feed receiving means
at the top of the column;
(f) contacting the feed material with the ascending liquid
stream;
lg) separating less dense material from heavier density
material, or smaller particle material from larger particle
material in the column;
(h) discharging the less dense or smaller particle material
at the top of the column;
(i) collecting the heavier density or larger particle
material at the bottom of the column; and
(j) discharging the heavier density or larger particle
material from the bottom of the column.
Yet another embodiment of the present invention provides
a method for separating a higher density material from a lower
density material, or a larger particle material from a smaller
particle material, derived from the breaking of lead-acid bat-
teries, the method comprising the steps of:
(a) introducing a liquid circumferentially through a
plurality of sized and spaced inlet ports into the lower portion
of an elutriation column having a circular horizontal
cross-section; the inlet ports being sized and spaced to control
the liquid introduced radially inwardly into the column to
produce a uniform ascending stream current having a sustained and
substantially constant velocity;
(b) establishing a uniform ascending liquid stream in the
column, the stream having sufficient flow velocity to lift the
lower density or smaller particle material to the top of the
column for discharge therefrom;
(c) introducing higher density and lower density feed
material having a predetermined nominal particle size, or larger
particle and smaller particle feed material, into the top portion
of the elutriation column
(d) separating the higher density material from the lower
density material, or the larger particle material
D
5d
from the smaller particle material, by action of the ascending
liquid stream thereupon;
(e) discharging the liquid and lifted lower density
material, or liquid and lifted smaller particle material, from
the top of the column;
(f) collecting the higher density or larger particle
material at the bottom of the column; and
~ g) discharging the accumulated higher density or larger
partic]e material from the bottom of the column.
In accordance with yet another embodiment of the present
invention, there is provided the method of separating a higher
density material from a lower density material, or a larger parti-
cle material from a smaller particle material, derived from the
breaking of lead-acid batteries, in a liquid elutriation column,
comprising the steps:
(a) introducing a liquid uniformly and circumferentially
radially inwardly into the lower portion of the column to
distribute the liquid and establish a uniform ascending liquid
stream having a sustained and substantially constant velocity,
the flow velocity being sufficient to lift all but the higher
density or larger particle material to the top of the column;
(b) feeding material having a predetermined nominal
particle size, or material having larger and smaller particle
sizes, into the top of the column to establish a descending feed
stream therein;
(c) contacting the descending feed stream with the
ascending liquid stream to disperse the material in the feed
stream, lift the lower density or smaller particle material to
the top of the column and allow the higher density or larger
particle material to fall to the bottom of the column
(d) discharging the liquid and the lower density or smaller
particle material from the top of the column; and
~ e) discharging the higher density or larger particle
material from the ~ottom of the column.
T~
~P
121(~17;3 S
In the above method and apparatus, preferably the relation-
ship of the diameter of the cylindrical portion of the column,
measured in inches, to the rate of liquid flow through the cylin-
drical portion of the column, measured in gallons per minute, i9
above approximately 1 to 25.
Preferably, the column has a truncated conical transition
section having the larger diameter end of the transition section
joined to an upper cylindrical column section equal in diameter
thereto and the smaller diameter end of the transition section
joined to a lower cylindrical column section equal in diameter
thereto; and a vertically adjustable, cylindrical material feed
inlet chute in axial alignment with and extending downwardly into
the upper cylindrical column section.
In another preferred embodiment, the horizontal cross-
sectional area of the lower cylindrical column section is substan-
tially equal to the effective annular cross sectional area
defined by the extexior wall of the chute and the interior wall
of the upper cylindrical column section.
Still further, the diameter of the upper cylindrical column
section is preferably sufficiently large to permit unrestricted
passage of the less dense material between the wall of the upper
cylindrical column section and the chute wall.
The vertically adjustable material feed chute is desirably
selectively vertically positioned to control the linear flow rate
of the liquid within the upper cylindrical column section.
In still further preferred embodiments, the elutriation
column comprises an upper cylindrical column portion, a central
cylindrical column portion and a lower column portion, the cylin-
drical feed inlet chute defining an effective horizontal cross~
sectional area between the outer surface of the feed inlet chute
and the inner surface of the upper column portion, and the hori-
zontal cross-sectional area of the central column portion is sub-
stantially equal to the effective horizontal cross-sectional
area.
D
12107~i
Preferably, the liquid introduced into the elutriation
column has a density of at least 1 and is preferably recycled in
a closed system.
_rief Description of the Drawings
Other objects, advantages and novel features of the present
invention will become apparent from the following detailed des-
cription of the invention when considered in conjunction with the
accompanying drawings wherein:
FIGURE 1 is a flow, or process, diagram showing the steps of
a battery reclamation method embodying the invention;
FIGURE 2 is a side view of a dewatering screen apparatus
used in carrying out the process of the invention,
FIGURE 3 is a side view of a water elutriation column appara-
tus used in carrying out the process of the invention;
FIGURE 3a is a sectional view of the elutriation column
showing constructional features and relationship of components of
the column; and
FIGURE 4 is a flow, or process, diagram showing another
reclamation method embodying the invention.
Best Mode for Carrying out the Invention
Figure 1 is a flow diagram showing the steps of the pre-
ferred embodiment of the process for breaking or crushing whole
composite batteries B for separating the broken parts into the
component material.
D
~%1(~73S
As shown, the first step of the process illustra-
tively comprises a step of breaking or crushing the
whole batteries into fragments of which a majority are
in fractions of less than l l/2 inch size. The
fragmentation causes substantially complete liberation
of the metal from the nonmetal materials and releases
the electrolyte. The metallic material comprises the
electrode active material, terminal posts and
electrical i~terconnectors. The nonmetallic material
comprises polymeric and possibly other electrically
nonconductive materials, and includes the case
material, which is usually of polypropylene, poly-
ethylene or hard rubber; spacers, if used; separator
material placed between the plates of the battery; and
other nonconductive materials.
It has been found thatj after the feeding of the
batteries through a conventional hammermill H, 97% of
the broken battery material is in a minus 1 l/2 inch
size fraction. Illustratively, such a hammermill made
by Williams Patent Crusher and Pulverizer Co., of St.
Louis, has hammers on concentrically located shafts
around a central drive shaft. The hammers strike the
battery case with an impact force against a steel
breaker plate to break the battery into fragments. The
batteries may be fed continuously by suitable conveyor
means into the hammermill. The hammermill with the
feed conveyor and inlet hopper are substantially
enclosed and ventilated to a conventional acid-mist
removing device. The acid-mist removing device, used
in processin~ lead-acid batteries, removes particles of
electrolyte and lead compounds from the air by
impingement or by spraying a scrubbing mist of water
therethrou~h, thereby maintaining the air substantially
acid-free and lead-free. Such devices are well known
lZ~)73S
and will not be described in detail here, as they are
commercially available.
Many of such batteries fed into the hammermill may
contain electrolyte within the battery case. Thus, the
parts of the hammermill which are exposed to such
electrolyte are preferably made of materials which are
corrosion-resistant with respect to the type of
electroly.e which may be present in the batteries being
processed, i.e., acid or alkaline. Resultingly, the
process is simplified by not having to drain the
electrolyte from the battery before the fragmentation
step.
The broken battery material, including any such
electrolyte, is then transferred, as by means of
gravity, into a mixing reactor M. In a mixing reactor
for lead-acid battery processing, the sulfuric acid
electrolyte is neutralized by adding sodium carbonate
in the form of soda ash. The electrolyte neutraliza-
tion step may be carried out as a batch process in the
mixing reactor. However, the present invention also
contemplates the step as being carried out as a
continuous process. In such processing of lead-acid
batteries, the amount of neutralizing reagent added to
the sulfuric acid electrolyte need only be adjusted to
compensate for the di$ferences in the volume and
concentration of electrolyte present due to the
quantity of batteries being processed. In the batch
processing method, the pH value is measured approxi-
mately every ho~r and neutralization reagent is added
accordingly.
In the continuous processing method, a pH probe is
preferably used to provide a continuous monitoring of
the pH, and adjustments are made as require~ in order
373S
to maintain the desired pH level. For neutralizing the
acid, a pH level of 7 is desired. However, in order to
provide for the conversion of lead sulfate to lead
carbonate and sodium carbonate to sodium sulfate, it is
S desirable to maintain a pH level of about 9.0 to 9.3.
The sulfuric acid reacts with sodium carbonate to form
sodium sulfate which is soluble and remains in solution
if the concentration of sodium sulfate is kept below
its saturation level to prevent crystallization and
precipitation of the compound.
It is desirable and advantageous to use a reagen~
which also reacts with the sulfur-containing lea~
compound from the electrode active material to form a
sulfur-free lead compound for subsequent recovery and
processing. The sodium carbonate also converts a sub-
stantial quantity of lead sulfate in the electrode
active material to lead carbonate. The amount of soda
ash required for the dual function of neutralizing the
acid and converting the lead sulfate preferably equals
the stoichiometric equivalent required for these
reactions plus at least a 10~ excess over the amount
required for the latter reaction. Additionally, it is
desirable to add sufficient water to maintain the con-
centration of the neutralization product, sodium
sulfate~ at about 90~ of its maximum solubility at
ambient temperature.
It was found from a test sample of 50 lead-acid
batteries that neutralizing of the sulfuric acid
required approximately 1.8q lbs. of 1~a2CO3 per
battery. I`o neutralize and remove the sulfur from the
electrode active material in a test sample of 200 lead-
acid batteries was fou~d to re~uire about 7.3 lbs. of
r~a2co3 per battery. The ~ifference in ~he amount
of Na2CO3 re~uired per battery comprises the
~21~)735
necessary additiona] amount of Na2CO3 to convert
the lead sulfate to lead carbonate. These exemplary
ap~roximations are not intended as limitations.
The present invention contemplates the use of
other neutralizing reagents for neutralizing the
sulfuric acid electrolyte, comprising, but not limited
to, reagents such as ammonium carbonate, sodium
hydroxide, ammonia, etc. For example, when ammonium
carbonate reagent is used, lead carbonate and ammonium
sulfate are the products; when sodium hydroxide reagent
is used, lead hydroxide and sodium sulfate are the
products and when ammonia is used, lead hydroxide and
ammonium sulfate are the products. Other reagents
will, of course, become readily apparent to those
skilled in the art and are contemplated for use herein.
All of the lead and lead compound products, as
well as the nonlead products, are valuable and are
preferably separated and recovered for their values, as
well as to control the purity of the desired end
product. Important advantages of this neutralization
step are the reduction of battery-electrolyte corrosion
of the equipment, and in lead-acid battery processing,
the desulfation of the sulfur-containing electrode
active material, or lead sulfate compound, by
conversion of this compound to a sulfur-free metallic
compound, such as lead carbonate, thereby greatly
simplifying its subsequent processing.
It is important to note that the electrolyte
neutralizing reagent may differ from the reagent used
to remove sulfur from lead sulfate in the electrode
active material. Additionally, electrolyte neutrali-
zation and active material desulfa~ion, or conversion,
may take place at di~erent times during processing.
l~lV'73S
~o
Since the electrode active material in lead-acid
batteries comprises lead oxides and lead sulfate, which
in the preferred process is converted to a substan-
tially sulfur-free lead compound, and all of these lead
compounds are desirably processed and recovered
together as environmentally desirable substantially
sulfur-free lead compounds for subsequent processing,
the specific process and timing of the conversion of
lead sulfate to sulfur-free lead may be varied consid-
erably. Alternatively, the lead sulfate may beprocessed through and reclaimed as lead sulfate for
later conversion to a sulfur-free compound in subse-
quent processing. For these reasons, no limitation is
intended to be placed upon the process sequence or the
specific process used in recovering and/or converting
electrode active material, as the recovery of such
material is the major factor, whether in the converted
sulfur-free or unconverted nonsulfur-free form. Such
electrode active material may, therefore, be referred
to herein as "electrode active material" or as "solid
lead compounds" without regard to whether or not such
conversion has taken place and the use of either of
these terms herein should be broadly interpreted as
being equivalent and interchangeable with the other for
the purposes of describing and claiming the process and
variations thereof set forth herein, as the actual
process sequence for such lead sulfate conversion to a
sulfur-free form is not considered to be critical.
In the next step, the battery material and
neutralized electrolyte, containing suspended solid
lead compounds, are fed to a dewatering screen where
the neutralized electrolyte and a majority of the solid
lead compounds are removed as hereinafter described. A
vibratin~ feeder may be used to transfer the broken
battery material to the header box on the dewatering
screen. A side view of the suitable dewatering screen
is shown in Figure 2. The operation of the dewatering
screen 20 involves introducing particles through a
feeder 22 and onto screen 26 having the desired
aperture size. The particles pass through screen 26 if
they are smaller than the apertures. They collect on
the screen 26 if they are larger. The smaller parti~
cles and liquid fall into chute 2g and the larger
particles fall off screen 26 at point 30.
It has been found that in the disclosed process,
over 90~ of the solid lead compounds, along with the
neutralized acid, passes through the screen. The most
common lead compound found in the electrode active
material, in addition to lead dioxide, is lead sulfate
which, as mentioned above, is converted to a substan-
tially sulfur-free compound, i.e., lead carbonate, in
the preceding neutralization step by controlling the
~0 amount of sodium carbonate neutralizing reagent used~
The solid lead carbonate and lead oxide compounds in
suspension in the neutralized electrolyte liquid, which
contains sodium sulfate in solution, are then pumped to
a solid-liquid separator tank S for settliny and con-
centration of the solids therein. Alternatively, theliquid, containing the suspended solids, may be
processed through a cyclone separator C which may be
added to supplement the solid-liquid separator to
concentrate and remove the solid material from the
liquid.
The solid-liquid separator allows the solid lead
compounds, in the form of lead carbonate and lead
oxides, to separate out of the sodium sulfate solution
lZ~0~73~
which is then separated ~rom the insoluble solids as by decant-
ing. Sodium sulfate solution adhering to the solid lead-
containing materials may be removed with a water wash. The
sulfur-free lead compounds thereafter may be smelted free of
environmental contamination as by sulfur pollution. The resul-
tant so~ium sulfate-rich li~uors can be concentrated and reco-
vered by evaporation to produce an anhydrous sodium sulfate pro-
duct.
The present inven-tion further contemplates the use of
other solid-liquid separation techniques and equipment. Any
means for separating the converted or unconverted electrode
active material from the electrolyte may be used within the
scope of the invention. In most cases, the active materials,
whether converted or unconverted, proceed throughout the pro-
cess together to be recovered simultaneously. ~he selected
separating means is dependent on the type of battery being
reclaimed. Thus, as nickel-cadmium, silver-zinc, nickel-zinc,
and lead-acid batteries have different electrode active mater-
ials and electrolytes, the recovery processes may be selected
accordingly.
Following the separation steps, the remaining cxushed, or
broken, solid oversize material 31 which does not pass through
the dewatering screen is conveyed to the top of a fluid elutria-
tion column or rising-current separator column. This oversize
material normally comprises both metal material and nonmetallic
components. The invention contemplates the use of various
liquids or liquid-solid suspensions as fluids for use in the
elutriation column. However, as indicated herefollowing, water
is preferred.
As shown in Figure 3, the novel elutriation column of the
present invention is comprised of an upper column portion
42a, a central column portion 42b and a lower column por-
tion 42c. Each portion of the column is circular in cross-
section and the upper column portion 42a is connected to the
central column portion 42b by a truncated, conical transition
section 62. A ver~ically adjustable inlet chute or feed funnel
46 is concentrically positioned at the top of the upper column
portion 42a with an inlet chute skirt 63 projecting into
upper column portion 42a as hereinafter further described.
13
A collection collar 60 is attached circumferentially around the
exterior of the upper column portion 42_ to receive overflow
liquid and lighter polymeric material 58 as they flow over the
overflow weir 59, formed by the upper circular lip of the upper
column portion 42a, and out the collection chute 61 to a de-
watering screen 64. As seen in Figures 3 and 3a, the collec-
tion collar 6~ has a sloped floor to direct the flow of liquid
and solids from the overflow weir to a collection chute ~1. A
heavy material exit chute 50 is connected to the lower column
1~ portion 42c to serve as a gravity feed path for movement of
heavier metal material 48 from the lower column portion 42c
through the heavy material exit chute 50 to an enclosed screw
conveyor 52. Rotation of the conveyor screw 53 causes the heav-
ier metal material 48 to be transported to the top of the screw
conveyor 52 and out the top for collection and subsequent pro-
cessing. An inlet pipe 40 is connected to a circumferential
liquid manifold 44 disposed about the lower portion of column
42 and which in turn is in liquid communication with the cen-
tral column portion 42b through a series of manifold inlet
ports or wall openings 45 selectively sized and positioned cir-
cumferentially through the bo~tom wall of the central column
portion 42b. As will be appreciated from Figures 3 and 3a,
through these inlet ports, liquid, which is continuously recir-
culated or recycled from the pump tank to the elutriation
column to form a closed system, is controllably introduced cir-
cumferentially into said central column portion 42b of the
elutriation column 42 to distribute the in~roduced liquid and
to establish a uniform upward flow pattern or ascendi~g stream
current having a sustained relatively constant velocity.
It will be appreciated by those skilled in the art that
the elutriation column must have minimum dimensions taking into
account the size of the particles so that clogging of the
column is avoided. As will be seen from Figures 3 and 3a,
the inside diameter in the central column portion 42b may be
several times the size of particles 48 and 58. The column dia-
meter D of central column portion 42b therefore has a minimum
diameter which prevents particle clogging of the area A'
(Figure 3a) and provides unrestricted particle movement up
~Z~(~7~S
13a
the upper column portion 42a, over weir 59 and into collec-
tion chute 61. The selection of diameter D of central column
portion 42b determines the cross-sectional area A of the cen-
tral column portion and also determines approximately the effec-
tive cross-sectional area A', defined as the cross-sectional
area between the cylindxical segment of upper portion 42a and
the outside of feed inlet chute skirt segment 63. As will also
be evident from Figures 3 and 3a, it likewise controls the
selection of the effective inside diameter D' of upper column
portion 42a and the maximum effective outside diameter D'' of
feed inlet chute skirt 63, as the effective cross-sectional
area A' between upper column portion 42a and feed inlet chute
skirt 63 desirably should be approximately equal to the cross-
sectional area A of the central column portion 42b if preven-
tion of particle clogging is to be achieved.
~ ith further reference to Figures 3 and 3a, it will beappreciated that the liquid manifold inlet openings or ports,
in conjunction with the quantity and pressure of liquid enter-
ing manifold 44 through inlet pipe 40, determine the liquid dis-
tribution and flow rate entering the column 42 to establish anupward flow pattern. ~y regulating the number, size and posi-
tion of the manifold openings 45, along with the regulation of
the liquid flow rate, a uniform upward flow pattern is esta-
blished. The manifold openings 45 preferably are sized and
positioned circumferentially 50 that liquid is controllably
introduced circumferential'y into said column to distribute the
inlet liquid and establish an ascending liquid stream having a
uniform upward flow pattern. Smaller manifold openings 45 are
positioned in line with the direct impingement of liquid flow-
ing into manifold 44 from inlet pipe 40 in order to control-
lably provide or introduce circumferentially a uniform liquid
flow into the column and establish the desired uni~orm ascend-
ing liquid stream.
The feed inlet chute or feed funnel 46 is axially or con-
centrically aligned with the top of the elutriation column 42,is vertically adjustable and is designed to receive the over-
size material 31 from dewatering screen 20. Feed inlet chute
46 has a cylindrical skirt portion 63 which projects into the
,~
13b
liquid and into the cylindrical segment oE upper column por-tion
42a to a point just above the bottom of said cylindrical seg-
ment .
Upper column portion 42a is comprised of t~o sections, a
cylindrical upper section and a lower -truncated conical transi-
tion section 62. The circular lip of the cylindrical upper sec-
tion serves as an overflow weir 59 and determines the liquid
level 56. The truncated conical -transition section 62 is
larger at the top and smaller at the bottom as shown in Figures
3 and 3a to cause the liquid velocity to decrease as the
ascending liquid enters the widening transition section and per-
mit the slower ascending liquid eurrent to act upon the solid
materials to lift them over weir 59 or permit them to sink
through the rising current and accumulate at the ~ottom of the
column. The truncated cone segment 62 at the upper portion of
the column is disposed between up~er and lower cylindrical
column segments and the material feed chute 46, extending down-
wardly into the upper cylindrical column segment 42a, is ver-
tically adjustable to control the linear flow rate of the
li~uid within the upper cylindrical column segment. under nor~
mal operating conditions, the solid materials will readily
separate and either rise and exit at the overflow weir or will
fall and accumulate at the bottom. If a significant amount of
material becomes suspended in the transltion section, adjust-
ment must be made in the liquid veloeity to eause the materialto either overflow at the weir or to fall and colleet at the
bottom, depending on the eomposition of the material and the
operator's desire.
The lower column portion 42_ serves to collect the heav-
ier material 48 in the heavy material exit chute 50 which gra-
vity feeds the material to enelosed serew conveyor 52 as the
screw conveyor is operated. The lower column portion 42c is
configured as desired to accommodate the selected discharge
means, such as the depieted inclined enclosed screw conveyor
whieh permits the discharge of the heavier material above the
li~uid level 56.
Table I sets forth the preferred embodiments of
applicant's novel elutriation column and preferred operatiny
lZ:1~73~
13c
parameters for a typical operation in separating lead-acid
battery materials which are fed to the column as above
described.
TABLE I
Dimensions and Relationships
of Elutriation Column and Components
Elutriation Column Dimensions:
Feet Inches
D" (O.D. of feed chute cylindrical
portion) l.. 01 12.16
D' (I.D. of upper column cylindrical
portion) 1.62 19.40
D (I.D. of central column cylindrical
portion) 1.25 15.00
L (Column length:distance from
liquid manifold to weir top) 5.58 66.9
Length of upper column portion
~42a) cylindrical segment 1.00 12.00
transition cone (taper=7) 1.49 17.90
Length of central column portion
(42~) 3.08 37.00
Length of lower column portion
(42c) 1.80 21.60
L' (Distance from bottom of feed
chute to weir top) 1.00 12.00
Rat~o of Co _mn Length to Effective Diameter of Column:
Maximum Ratio 6:1
Preferred Ratio 4.5~1
Cxoss-Sectional Areas:
A tCentral column portion) 177 in2
A' (Effective area between I.D. of
upper cylindrical portion and
O.D. of feed chute) 179 in2
1~
~Z1~73S
13d
Characteristics of Liquid and Liquid Flow:
Liquid linear f]ow velocity (typical rate) 50 ft/min
Liquid 1ow rate (typical rate) 450 to 500 gal/min
~i~uid (preferred) water
In operating the elutriation column as shown in Figures 3
and 3a, liquid, recycled from the pump tank T is introduced
circumferentially uniformly through an inlet pipe 40 near the
bottom of the column 4~ at a controlled pressure. Manifold 44
uniformly distributes the inlet liquid to establish a controlled
upward liquid velocity and a uniform ascending liquid flow
pattern. As broken oversize battery material 31 is introduced at
the top 46 of the column~ the heavier metal material 48 sinks to
and collects at bottom 50 of the column. An enclosed screw
conveyor 52 continuously removes the collected metallic material
48. ~s shown in broken section ~FIG. 3), screw conveyor 52 is of
sufficient length to extend above the liquid level 56 in the
column so that the metal material may be readily collected in a
container without need to remove liquid. The small amount of
electrcde active material, or suspended solids, remaining in the
process stream and the nonmetallic material, such as the
polymeric material, illustratively polypropylene piece 58, is
maintained in fluid suspension in the elutriation column. The
polymeric, or nonmetallic, material and suspended solids are
carried by the upward water flow over overflow weir 59 to a
collection collar 60 from which the flow exits through collection
chute or collar 61, permitting the nonmetallic material to be
further processed in a subsequent processing step.
It has been found that a critical factor aEfecting
separation efficiency in the Eluid elutriation column is the use
of an optimum fluid flow rate. With an appropriate flow
rate using water as the fluid, for example, the elutriation
separation of the polymeric material, including hard rubber
material and solid lead compounds in suspension, from
the lead metal material has been caused to be over 97%
efficient. Illustratively, an elutriation column having a
15-inch diameter and a water flow rate of 450 to 500 gallons of
water per minute providing an average linear flow rate of
f~
~L~73S
14
about 50 ft/min up the column has been found to provide
such a high separation efficiency.
The fluid used in the elutriation column may be
recirculated as by being pumped from a return pump tank
T~ After the fluid has flowed through the column, it
may be returned to the pump tank where the suspended
solid lead compounds are removed via a bleed stream
outflow. It has been found to be advantageous to
remove the solids in the bleed stream from the return
pump tank as by use of a hydraulic cyclone separator,
as previously mentioned, as well as other solid-liquid
separators as desired.
Remaining oversize solids which may comprise
broken polymeric material, such as polypropylene, hard
rubber and separator materials, are conveyed to a
solid-solid separator S-S which is a liquid-filled tan~
where the different materials are separated. In the
preferred embodiment, this is a sink-float step. The
density of the material to be separated determines the
appropriate liquid or liquid-solid suspension as the
desired separator medium. In the preferred embodiment,
water is used. The hard rubber and other polymeric
materials which have a density greater than water, sink
to the bottom of the separation tank where a screw
~5 conveyor S-S removes the material from the liquid bath
for collection. The screw need be only of sufficient
leng~h to extend above the liquid level of the bath so
that the denser polymeric material will be freed of
liquid as it is collected. The other polymeric
materials, having a density less than that of the
liquid used, float on top of the bath and are removed
by a cleated continuous belt conveyor B-C which extends
just below the liquid ~evel. One important advantage
~LZ~(~73S
of this step, from a product purity viewpoint, is
removal of undesirable heavier polymeric materials,
such as polyvinyl chloride and hard rubber which sink
and are thusly separated from the lighter floating
polymeric materials. This allows the material to be
recycled more efficiently by providing a starting
material having fewer contaminants, such as chloride
compounds, from the remaining polymeric material and
lead compounds to be processed.
While the operation described above is a solid-
solid separation, the present invention contemplates,
within the scope of the invention, the use of other
means for separating the solid materials. Such means
may be similarly based on the density of the solid
materials or may use other chemical or physical proper-
ties of the material being processed to accomplish the
separation.
Another embodiment of the present invention is
shown in the flow diagram of Figure 4. In the Figure 4
embodiment, the electrolyte, electrode active material
and other undersized solid material are separated from
the remaining crushed or broken battery material
without neutralizing the electrolyte so that it may be
collected and reused. ~s shown, the electrode active
material is separated from the unneutralized electro-
lyte by a solid-liquid separator means.
The electrolyte may be neutralized at a subsequent
time during processing if desired. The electrolyte
neutralizing reagent may differ from the reagent used
to remove sulfur from the electrode active material.
Additionally, in processing lead-acid batteries,
desulfation may be effected at subsequent times and in
different steps during the processing.
lg735
16
The oversize solid material which is separated
from the smaller broken battery material is normally
wet with unneutralized electrolyte. It has been found
that approximately 10~ of the electrolyte adheres to
the oversize solid material and, thus, during subse-
quent processing, it may be desirable to neutralize the
electrolyte adhering to the oversize solid material
before further processing. The remaining steps of the
embodiment shown in Figure 4 are similar to the
embodiment previously discussed.
As demonstrated by the disclosed embodiments, the
present invention provides a process for reclaimin~, in
relatively pure form, and as separate products, the
different components of storage batteries. Such
recovery includes a sulfur-free, environmentally
desirable, active material product from lead-acid
batteries. Since the electrolyte does not need to be
drained from the storage battery before processing, the
operation is simple and economical. Where the battery
electrolyte is neutralized, as in the preferred
disclosed process, the mechanical apparatus used in the
subsequent steps of the process need not be made of
expensive corrosion-resistant metal. The work enviroll-
ment is made less hazardous to personnel and
environmental problems concerning waste disposal and
sulfur and lead content in the air are significantly
reduced.
This invention provides a simplified process for
the separation of the various constituents of storage
batteries, including the active material, grid and
other metal material, electrolyte, polymeric materials
including spacerl container, insulator, and other
nonmetallic materials. These m~terials are ~eparated
3~2~
17
and recovered in a form sufficiently free of contamina-
tion to permit efficient and economical recycling
thereof with minimum adverse impact on the environment.
The present invention is adaptable to be used to
recover components of batteries other ~han lead~acid
batteries.
The foregoing disclosure of specific embodiments
is illustrative of the broad inventive concepts
comprehended by the invention.
