AU2009200812A1

AU2009200812A1 - Battery recycling

Info

Publication number: AU2009200812A1
Application number: AU2009200812A
Authority: AU
Inventors: Vincent Huang
Original assignee: Individual
Current assignee: Individual
Priority date: 2008-02-28
Filing date: 2009-03-02
Publication date: 2009-09-17
Anticipated expiration: 2029-03-02
Also published as: AU2009200812B2

Description

P/00/011 Regulation 3.2 AUSTRALIA Patents Act 1990 ORIGINAL COMPLETE SPECIFICATION STANDARD PATENT Invention Title: "BATTERY RECYCLING" The following statement is a full description of this invention, including the best method of performing it known to me/us: 1 BATTERY RECYCLING FIELD OF THE INVENTION The present invention relates to the field of battery recycling. More particularly, this invention relates to a process and apparatus for the 5 recycling of lead-acid batteries. BACKGROUND OF THE INVENTION Lead-acid batteries are currently the most commonly used rechargeable battery in the world. They are simple and inexpensive to manufacture and have high discharge rates which allow them to produce 10 high surge currents. These features have led to their use in a range of applications such as storage devices for energy derived from solar and wind technologies as well as in cars to provide the high current required by starter motors. Lead-acid batteries typically have a life span of 3-4 years, after which 15 time they cannot be effectively recharged and must be replaced. Due to their popularity this results in an enormous number of these devices which must be destroyed. This means the content of the batteries, typically being lead, sulphuric acid, plastics from the battery casing and smaller amounts of additives such as antimony and arsenic must be disposed of or reclaimed. 20 It is desirable to recycle these components due to both the environmental concerns associated with improper disposal of the heavy metals and corrosive acid and also to recoup value from the components. Lead in particular is a valuable commodity and can be used, amongst other things, in the production of new lead-acid batteries.

2 Typically, recycling of lead-acid batteries is carried out in large scale smelting operations which generally entail smelting of the intact battery. Running a smelting operation is a very costly exercise which can only be sustained by a limited number of large companies. Further, some of the 5 individual components of the battery which have residual value will be lost in the smelting process. The present inventors have, therefore, identified a need for an efficient and cost-effective method of recycling lead-acid batteries which would be accessible to many smaller battery recycling companies. 10 SUMMARY OF THE INVENTION The inventors have identified a need for an effective method for processing lead-acid batteries to enable one or more of the constituent parts to be isolated so as to allow value to be recouped from the used batteries. In one form, which is not necessarily the only or broadest form, the 15 invention provides for a method of reducing a lead-acid battery to its constituent parts for further use and/or recycling. In a first aspect, the invention resides in a method of isolating one or more constituent materials of a lead-acid battery including the steps of: (a) dismantling the battery; and 20 (b) substantially separating metallic and non-metallic constituents of the battery. In one particular embodiment of the first aspect, the method further includes the step of shredding the non-metallic constituents. Preferably, the metallic constituents comprise lead and/or lead salts 3 which are separated from the non-metallic constituents without the need for a smelting operation. If required, the metallic and non-metallic constituents may be separated by hand, by gravity or according to their relative density. 5 Preferably, the metallic and non-metallic constituents are separated according to their relative density in water or sulphuric acid. The metallic and/or non-metallic constituents of the battery may be treated to reduce their sulphur content. Preferably, the treatment comprises exposing the metallic and/or non-metallic constituents of the battery to an 10 alkaline suspension or solution, which in certain non-limiting examples may be sodium carbonate, calcium carbonate, magnesium carbonate, alkali metal hydroxide, or alkali metal hypochlorite. Particularly preferred solutions are a sodium carbonate solution, sodium hypochlorite solution or a sodium hydroxide solution. 15 Suitably, one or more of the steps in the method of isolating one or more constituent materials of a lead-acid battery are automated. A second aspect of the invention resides in an apparatus for use in isolating the constituent materials of a lead-acid battery, the apparatus comprising a battery dismantling component and a separating component 20 and wherein the constituent materials of the battery are released in the battery dismantling component and subsequently enter the separating component. Preferably, the apparatus of the second aspect allows substantially pure lead and/or lead salts to be obtained from the battery.

4 Suitably, the separating component comprises a gravity separation and/or a density separation. In one particular embodiment of the second aspect the apparatus further comprises a plastic shredding component for non-metallic 5 constituents which are removed from the separating component. Throughout this specification, unless the context requires otherwise, the words "comprise", "comprises" and "comprising" will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers. 10 BRIEF DESCRIPTION OF THE FIGURES In order that the invention may be readily understood and put into practical effect, preferred embodiments will now be described by way of example with reference to the accompanying figures wherein like reference numerals refer to like parts and wherein: 15 FIG 1 is a diagrammatic representation of a method of isolating the constituent materials of a lead-acid battery according to an embodiment of the invention; FIG 2 is a diagrammatic representation of a method of isolating the constituent materials of a lead-acid battery according to a further 20 embodiment of the invention; FIG 3 is a representation of one embodiment of a battery processing apparatus of the second aspect; FIG 4 is a representation of one embodiment of a battery processor component of the apparatus shown in FIG 3; 5 FIG 5 is a representation of one embodiment of a shredding component of the apparatus shown in FIG 3; FIG 6 is a representation of one embodiment of a lead sludge processing component of the apparatus shown in FIG 3; 5 FIG 7 is a representation of one embodiment of a lead plate processing component of the apparatus shown in FIG 3; and FIG 8 is a representation of a further embodiment of a battery processing apparatus of the second aspect. DETAILED DESCRIPTION OF THE INVENTION 10 FIG 1 is a diagrammatic representation of a method of isolating the constituent materials of a lead-acid battery according to an embodiment of the invention. The present method allows the inherent value in the constituent materials of the lead-acid battery to be recouped without the need for a smelting operation which results in the destruction, and hence 15 loss of value, of many of said constituents. The battery may be dismantled in any one of a number of ways so long as the battery casing is completely opened to reveal the constituent materials and the electrolyte solution of sulphuric acid in water is able to drain away. It is preferable, however, that in the dismantling step the battery 20 casing be substantially fragmented. The dismantling may, for example, involve cutting, crushing or shredding of the battery. Preferably, the battery is crushed. The dismantling process serves to open the battery and fragment the casing so as to release the sulphuric acid and allow the various constituents to be accessed. It is not 6 designed to crush or substantially fragment the lead plate contained within the battery. It is preferable if the lead plate is kept relatively intact throughout the process, at least as much as is practically possible. During dismantling of the battery casing the sulphuric acid electrolyte 5 is released. This is isolated from the other battery constituents and collected. The sulphuric acid may be collected in a receptacle for storage or further processing, such as purification and/or increasing its concentration, or may be drained directly into a transport container for delivery to a customer. There is inherent value in the sulphuric acid and it is an advantage of 10 the present method that it can be separated from the other constituents of the battery and collected for further processing, re-use or re-sale. The acid collected may, for example, be used as a fertiliser ingredient, for ore processing or as regenerated electrolyte in new lead-acid batteries. The next step involves separating the metallic and non-metallic 15 constituents of the battery. Typically, the metallic constituents are, primarily, the lead plate, lead oxide paste and other lead salts which formed the electrodes of the battery, as well as a variety of other heavy metals and metal-containing constituents. These must be separated from the non metallic constituents typically being the plastic battery casing, linings, 20 separators and other small components. The separation step may be performed in a number of ways. Some non-limiting examples are the separation of the constituents manually, under the influence of gravity, by their differing relative densities or a combination of these processes.

7 Preferably, the metallic and non-metallic constituents are suspended in the sulphuric acid which is released when the battery is dismantled and thereby separate out based upon their relative densities. The plastic components will float on the surface of the acid and the lead constituents will 5 sink to the bottom. Alternatively, the metallic and non-metallic constituents are first separated out by shaking, vibrating or rotating them on an angled surface such that the heavier metallic constituents will be substantially separated, under the influence of gravity, from the lighter substantially non-metallic 10 constituents. There may well be a gradient of separation and so some plastic fragments may still contain small pieces of metal. If this process does not separate the constituents to the required degree then the substantially pure metallic constituents can be removed and the remaining, lighter, components placed in a water bath. The lightest or 15 least dense fragments which represent substantially pure plastic will float and hence can easily be removed from the water's surface. The heavier fragments which may consist of small pieces of metal and plastic containing small quantities of metal will sink to the bottom and can be recovered separately to be subjected to further processing. 20 The collected metallic constituents can then be pooled and, if necessary, washed and dried. The washing will remove any residual sulphuric acid and, as will be discussed later, other sulphurous materials and may conveniently be carried out in a water bath or using jets or a tumbler or trommel dispensing water and/or chemical wash solutions comprising 8 compounds such as sodium carbonate, calcium carbonate, magnesium carbonate, alkali metal hydroxides, alkali metal hypochlorites. Preferred solutions are caustic soda, potassium hydroxide, sodium carbonate solutions or suspensions or sodium hypochlorite solutions. Drying can be performed 5 using an oven, a hot air stream, centrifugation of the metal constituents or simply drip drying. Then, depending on the application they will be used for, the metallic constituents are ready for sale, further processing or smelting to provide a relatively pure source of lead. The lighter, substantially plastic, constituents are also pooled, washed 10 and dried as described above. If oven drying is used then lower temperatures will be used than for the metallic constituents. The plastic components can then be recycled or used for their calorific value. In one particular embodiment of the first aspect, the method includes the step of further shredding the plastic components, which have already 15 been substantially separated from the lead plate, to enable the separating out of any further metallic constituents which might be attached to the large plastic fragments. This shredding step may be performed if it appears that a significant amount of the plastic fragments and other non-metallic constituents have metallic pieces still attached to them after the initial step of 20 dismantling the lead-acid battery. The shredding step will involve further diminution of the plastic fragments to thereby free up or separate the metal from the plastic. The word shredding as used herein encompasses the acts of cutting, tearing, crushing, grinding or any other means of reducing the fragment sizes to achieve the 9 stated result. The shredding of the plastic and other non-metallic constituents may occur at any stage after the dismantling of the battery. For example, it may be employed after the initial separation of the metallic and non-metallic 5 constituents and the separation step using gravity, density or manual separation repeated to improve the degree of separation at this stage. Alternatively, the shredding may be carried out only on the plastic constituents containing some metal which sink to the bottom of the water bath during further separation of the substantially non-metallic constituents 10 as described above. FIG 1 is a diagrammatic representation of a method 10 of isolating the constituent materials of a lead-acid battery according to an embodiment of the invention. The skilled addressee would understand that the steps described may also be performed in a different order to that shown in FIG 1 15 and described herein so long as the desired goal of the dismantling of the battery and the isolation of its constituent materials is achieved. In the embodiment represented by FIG 1 the dismantling step takes place at dismantling station 11 whereupon the battery casing is opened and sulphuric acid electrolyte is drained and collected in collection tank 12. 20 The metallic and non-metallic constituents, being mostly lead and plastic, are separated at separating station 13 whereupon the separated lead containing constituents are sent to first wash station 14. Wash water and/or a bleach or an alkali metal hydroxide solution, such as caustic soda, is supplied by reservoir 15. First wash station 14 may also be a centrifuge 10 which subsequently dries the metallic constituents. The plastic constituents may be sent straight to second wash station 16 or may first be directed to shredding station 17, where any remaining metallic parts are separated from the plastic and recovered. The plastic 5 fragments can also be reduced in size. These additional metallic constituents are sent to first wash station 14, either to be pooled with the others or to replace them after their removal, while the plastic constituents are sent to second wash station 16. Second wash station 16 may also be a centrifuge which subsequently 10 dries the plastic and other non-metallic constituents. The main components of value from the lead-acid battery, being the lead, plastic and sulphuric acid, are thereby isolated and ready for further processing or sale. It will be understood that although FIG 1 represents many of the actions as discrete stations it does not necessarily have to be this way. For 15 example, dismantling station 11 and separating station 13 may be performed at the one location or station. FIG 2 is a diagrammatic representation of a method of isolating the constituent materials of a lead-acid battery according to a further embodiment of the invention. The skilled addressee would understand that 20 the steps described may also be performed in a different order to that shown in FIG 2 and described herein. Other steps may also be included or certain steps removed or combined so long as the desired goal of the dismantling of the battery and the isolation of its constituent materials is achieved. In the embodiment represented by FIG 2 the lead-acid batteries enter 11 the system at battery input 111 which may involve a hydraulic ram lift or use of a forklift to introduce a number of batteries simultaneously to battery dismantling apparatus 112 which will break open the batteries in the manner discussed for FIG 1. 5 The constituent materials of the battery enter separating tank 113 which, consequently, becomes full of sulphuric acid, lead plate, lead oxide paste and plastic fragments. The plastic components, being less dense than the acid, will float on the surface and are free to enter plastics gravity separator 114, which in one non-limiting example takes the form of one or 10 more rotating augers. The plastic fragments move along gravity separator 114 and are exposed to plastics wash station 115 which will typically be made integral with or closely associated with separator 114. This washing removes the sulphuric acid and aggregated lead paste from the surface of the plastic fragments and may be a water wash or may contain caustic soda 15 or the like. Washing overflow tank 117 captures the washings from wash station 115 and recirculates them for re-use. Similarly, acid overflow tank 118 captures the acid that flows from separating tank 113 into separator 114 along with the plastic fragments and enables it to be pumped back into 20 separating tank 113. The lead paste that is washed off the plastic fragments during their passage along separator 114 is collected in lead paste return tank 119 and pumped back into separating tank 113. After passing through wash station 115 the plastic fragments are collected as the cleaned and isolated plastic fragments 116.

12 The lead plate and lead paste in separating tank 113 will, of course, sink to the bottom and can then be removed via lead removal pump 120 as a thick sludge containing solid lead plates. This sludge is introduced to lead gravity separator 121 which, in one non-limiting example, may take the form 5 of one or more rotating augers. Lead wash station 122 may be integral with or associated with lead gravity separator 121 and has the dual effect of washing the lead paste off the lead plates and also reducing the sulphur content of the lead by the use of a caustic soda washing solution, or the like. The substantially pure, washed and sulphur free lead plate product 10 123 is ejected from wash station 122 into a suitable container. The lead paste which is washed off the lead plate in wash station 122 is captured and passed through one or more sulphur reducing solutions 124. The lead paste is thoroughly mixed with these solutions and allowed to sit for a sufficient period of time to remove substantially all of the sulphur content of 15 the paste. The sulphur reduced lead paste and caustic solutions are then pumped into drying unit 125 which may take the form of a filter press, centrifuge or the like. The moisture content of the lead paste is thus greatly reduced and substantially pure lead paste 126 is removed. 20 After use the sulphur reducing solutions 124 and caustic washings removed from the drying unit 125 are combined in moisture removal station 127 and the salt product 128 generated from them. This can be achieved by a number of methods known in the art, such as evaporating the water to leave sodium sulphate (if caustic soda was the wash solution used) as a 13 powder or crystallisation of the product from minimal water. The salt product is then easier to remove and may have value as a chemical feed in its own right, for example as a common drying agent in synthetic laboratories. The sulphuric acid is removed from separating tank 113 and may be 5 used as is or may be sent to acid concentrating station 129 which may take the form of a vacuum evaporator or the like. Here, a pre-determined volume of water is removed to generate a more concentrated sulphuric acid solution, which is typically in greater demand in a number of industries, than the approximately 15% solution found in lead-acid batteries. 10 In the manner just described, a method for dismantling a number of lead-acid batteries simultaneously and then isolating the individual components of value has been provided. This method provides for minimum wastage, treats the sulphur component in an environmentally friendly manner by combining it into salt form and extracts value from substantially all of the 15 battery components. Suitably, one or more of the steps in the methods of isolating the constituent materials of a lead-acid battery, as described above, are automated. The advantages of automation in industry are well known. Automation 20 of one or more steps in a process can improve the efficiency of that step, provide savings in labour costs, increase the daily operation time and, in the case of potentially hazardous steps, improve work place safety. Accordingly, any of the steps described above may be performed using a suitable apparatus, for example, the dismantling, separating, 14 washing, drying, and shredding steps may all be automated. It is important for reasons of both safety and efficiency that an appropriate apparatus be used for any automated step. It is a further advantage of the present invention that such an apparatus is provided as described below. 5 A second aspect of the invention resides in an apparatus for use in isolating the constituent materials of a lead-acid battery, said apparatus comprising at least a battery dismantling component, and a metal and/or plastic separating component. FIG 3 is a representation of one embodiment of a battery processing 10 apparatus of the second aspect. Battery processing apparatus 100 comprises battery dismantling and separating component 20, shredding and separating component 40, lead sludge drying component 60 and lead plate drying component 70. These components are shown as discrete stations but may be linked by the use of conveyor belts, piping or other suitable means. 15 The individual components will be discussed in more detail below. FIG 4 is a representation of one embodiment of a battery dismantling and separating component which can be used to perform the first step in the method of isolating one or more constituent materials of a lead-acid battery, being the dismantling of the battery. The battery dismantling and separating 20 component 20 comprises a battery platform 21 to support the lead-acid battery 22 and a battery dismantler, here shown in the form of hammer 23, which can be actuated by means of a cork-screw motion, a pulley system or motorised belt or the like to descend to contact battery 22, fragment the casing and hence release the constituent materials. Hammer 23 may be 15 deployed more than once if necessary. The constituents of battery 22 are thus laid open upon platform 21. The lead plate and any other larger metallic constituents can then be removed manually through hatch 24, which thus represents the first 5 separation step. Platform 21 may be porous with an angled drain underneath to catch and direct the sulphuric acid electrolyte into drain 25. Platform 21 may be hinged or slidable in a horizontal fashion such that it can be opened to allow the non-metallic and smaller metallic constituents to fall through to conveyor belt 26 which has teeth 27. Teeth 27 are large 10 enough to allow small metallic constituents, such as lead sludge, to sit in the gaps between each tooth but small enough that the larger plastic fragments will sit on top. Teeth 27 may also be partially submerged in water such that smaller plastic fragments are also kept near the surface and all the metallic constituents sink between the teeth 27, which represents a further separation 15 of the battery constituents. Conveyor belt 26 moves teeth 27 initially towards hatch 28 where the plastic and other non-metallic fragments may be removed manually. Conveyor belt 26 then continues in a circular fashion with the small metallic constituents being carried between teeth 27 to eventually be expelled onto 20 auger 29 (hashed lines indicate the auger cork-screw like motion). The lead sludge and other small metallic constituents are carried up auger 29 and exposed to jets 30 (not shown in detail in FIG 4) which may expel water or a sulphur-reducing solution, such as caustic soda or the like. The jets 30 will help to wash away any residual sulphuric acid and, 16 importantly, they reduce the sulphur content of the lead sludge. This provides for an end product which is more amenable to further processing in smelting or other lead processing operations. The removal of as much sulphur as possible at this stage gives higher yields of lead material of increased purity 5 which increases its feedstock value. It also leads to lower sulphur emissions during smelting and so results in benefits to the environment. The lead sludge is then expelled via output channel 31 into a container 32. In one particular embodiment of the second aspect the apparatus further comprises a plastic shredding component. 10 The plastic and any other non-metallic constituents which were collected from hatch 28 of the battery dismantling and separating component 20 and which still have some metallic constituents attached to them can now be fed into shredding component 40 as shown in FIG 5. This component can also be used simply to reduce the size of any large plastic fragments 15 FIG 5 is a representation of one embodiment of a shredding and separating component 40 which can be used for further dismantling or diminution of some constituent materials of the lead-acid battery, if required. The plastic and any other non-metallic constituents to be shredded are fed into inlet 41 and pass down into shredding unit 42 which takes the form of a 20 circular grinding wheel driven by a motorised belt system. After being reduced in size in shredding unit 42 the small fragments are allowed to fall through onto conveyor belt 43 which has teeth 44. The plastic and metallic constituents are then separated out substantially as described for conveyor belt 26 in FIG 4.

17 Teeth 44 deliver the plastic fragments via a series of brushes or the like (detail not shown) which sweep the plastic off the top of teeth 44 and onto the rotating section of plastics auger 45 where any residual sulphuric acid, sulphur or metal pieces are washed off by jets 46 (detail not shown), as 5 described previously for battery dismantling and separating component 20. The plastic fragments are then expelled through output 47 into container 48. The lead sludge and any other small metal fragments which sit in the troughs between teeth 44 are delivered by the continuing circular motion of conveyor belt 43 to lead salts auger 49. The lower extent of the auger 49 sits 10 under the teeth 44 such that when conveyor belt 43 passes over this region the lead sludge is either washed or brushed off and into said auger 49. Once again, jets 50 remove any remaining acid or sulphur residues from the lead sludge as it moves up auger 49. The metal sludge then passes through outlet 51 into container 52. The water, diluted sulphuric acid and other 15 impurities are washed down from the augers 45 and 49 into drain 53 for collection or diversion to waste. At this point lead plate, lead sludge, sulphuric acid and plastic casing have all been separated out from the dismantled lead-acid battery and washed, where necessary. The lead obtained is then available for further use 20 or re-sale. Lead has a high market value and it is a particular advantage of the present invention that it can be recycled from lead-acid batteries in such a simple, efficient, environmentally responsible and cost-effective manner. Additional value has also been extracted from the batteries by the isolation of the sulphuric acid and plastic battery constituents.

18 In an alternative embodiment, the plastic and other non-metallic constituents removed from battery dismantling component 20 may be placed in a density separation apparatus, such as a water bath, which may also contain caustic soda, before being introduced to shredding component 40. 5 The heavier constituents which may have some metallic fragments attached will sink to the bottom of the water bath while substantially pure plastic will remain on top. This allows their separation so that only the impure plastic fragments need be introduced to shredding and separating component 40, unless a reduction is fragment size is desired. The water bath also acts as a 10 further cleaning step to remove acid and reduce the sulphur content of the constituents. One or more of the metallic or non-metallic constituents may undergo further washing and/or drying steps before being stored for further use or sale. This can help further purify and/or reduce the weight of the constituents 15 to enable easier delivery to the customer. FIG 6 is a representation of one embodiment of a lead sludge drying component. The lead sludge will largely comprise lead oxide, with other lead salts present in smaller amounts. The lead sludge drying component 60 has filter-centrifuge chamber 61 defined by centrifuge wall 62. The filter 20 centrifuge spins around central rotor 63 which is driven by motor 64 via one or more belts 65. The filter-centrifuge is supported on a platform by spring 66 which aids in dampening any vibratory motion and is affixed to the floor by stand 67. The lead sludge can be introduced into filter-centrifuge chamber 61 19 after removal from one of components 20 or 40 by pumping it from one of the other stations or components or a storage container via lead input pipe 68. Filter-centrifuge chamber 61 may initially wash the sludge with water and any other solvents or chemical scrubs which may be desirable, such as 5 caustic soda. This further reduces the sulphur content of the sludge which is beneficial for reasons described previously. After washing, the liquid component is drained away and the filter-centrifuge is turned to centrifugation mode. This spins the sludge, forcing it against the inner surface of centrifuge wall 62 and forces out moisture collected during the 10 separating and washing processes. Centrifugation is continued until the sludge reaches the desired minimum moisture content. Lowering the moisture content in this way reduces the weight of the sludge which lowers transport costs and means less heat energy is wasted in any subsequent smelting operation which the customer may employ. 15 The reduced moisture content sludge can then be removed from filter centrifuge chamber 61 by the use of a forklift, for example, and is ready for further use or sale. FIG 7 is a representation of one embodiment of a lead plate drying component. Lead plate drying component 70 operates in a somewhat similar 20 manner to lead sludge drying component 60. It has a filter-centrifuge chamber 71 defined by centrifuge wall 72. The filter-centrifuge spins around central rotor 73 which is driven by motor 74 via one or more belts 75. The filter-centrifuge is supported on a platform by stands 76 and 77. The lead plate is placed into filter-centrifuge chamber 71, typically 20 using a forklift. It is then washed and dried, using centrifugation, as previously described. After drying, the lead plate can be conveniently removed using a forklift. In this manner substantially all constituents of the battery, but 5 particularly the lead component which has the greatest inherent value, are released from the battery casing, separated out, processed, washed and dried for transport, sale or further processing as desired. In one preferred embodiment of the second aspect, an apparatus is provided as shown in FIG 8. This apparatus provides almost complete 10 automation and linking of the various steps already discussed and provides a number of advantages in use, as will be discussed below. FIG 8 is a representation of a battery processing apparatus 100. Battery processing apparatus 100 comprises a battery dismantling component 200 having an inlet funnel 201, two or more dismantling 15 members 202 and dismantling surface 203. The lead-acid batteries 205 are fed into inlet funnel 201 by the use of a hydraulic ram lift or a forklift. This enables a number of batteries 205 to be fed into the system simultaneously. To ensure inlet funnel 201 is not overloaded or does not back up with batteries 205 if the apparatus should fail, one or more volume and/or weight 20 sensors will be employed (not shown in FIG 8) which are connected to a computer system and are thereby monitored constantly. If the batteries 205 begin to back up in the inlet funnel 201 then the computer will be fed this information by the sensor and will automatically bring about an appropriate action such as raising an alarm and/or preventing further batteries from being 21 introduced. Dismantling members 202 can be formed from two adjacent solid bodies with teeth or similar structures projecting from their surface to form a dismantling surface 203 such that when the bodies rotate the teeth engage. 5 As the batteries 205 are forced into the dismantling surface 203 by their own weight they are crushed and partially shredded by the teeth such that the components of the battery are released. The rotation or crushing motion of dismantling members 202 is driven by motor 204. After passing through the dismantling surface 203 the battery 10 constituents fall directly into separation component 300. Separation component 300 comprises a separation tank 301 located beneath dismantling surface 203 so as to catch all of the battery constituents. Separation tank 213 thus fills up with sulphuric acid and so the plastic fragments from the batteries float on top and the lead plate and lead paste 15 sink to the bottom. An initial separation of the battery constituents is thus achieved. A plastics separator, in the form of first rotating auger 302, is in open communication with the upper extent of separation tank 301 and, indeed, the level of the sulphuric acid is seen to extend into the body of first auger 302. 20 The plastic fragments, which may contain some lead paste on their surface, are thus free to float into the body of first auger 302 and are carried along by its rotating action which is driven by motor 303. As the plastic fragments are tumbled around in the lower extent of first auger 302, which is submerged in the acid, the sulphuric acid will act to wash off most if not all of the lead 22 paste. The plastic fragments are then released from the upper extent of first auger 302 into plastics wash tank 306 which acts to wash off traces of sulphuric acid. Second rotating auger 304, which is driven by motor 305, is in 5 open communication with plastics wash tank 306 and so the plastic fragments are drawn up its extent and in the process may be exposed to water jets to remove the final traces of acid. The plastic fragments may subsequently be exposed to an air stream, hot or otherwise, to begin the drying process. At the upper extent of second auger 304 the plastic 10 fragments are released into a container 309 where they will quickly dry and are ready for further use or sale. Acid collection tank 307 is situated under first auger 302 to collect excess sulphuric acid which can drip through the porous floor of said auger 302. Wash collection tank 308 is likewise situated under second auger 304 15 to collect the wash water for recycling and further use. At the same time the plastic components of the batteries are being processed the lead plate and paste which collects at the lower extent of separation tank 301 is transported, via lead removal pump 310, into a lead gravity separator, in the form of third rotating auger 311. The action of third 20 rotating auger 311 draws the lead sludge and plate along its extent during which time they are sprayed by high pressure jets with water or a caustic soda solution which acts to wash the lead paste from the surface of the lead plate, neutralize the sulphuric acid and also begins the process of sulphur removal.

23 The lower extent of third rotating auger 311 is in open communication with the upper end of lead paste collection tank 313. As the lead paste is washed down by the caustic solution both are collected in tank 313 which maintains the paste in a caustic soda or like solution to aid in removal of 5 sulphurous compounds. The lead plate reaches the upper extent of third rotating auger 311, driven by motor 316, having been cleaned of lead paste and acid and may undergo a final water wash and/or drying step before being ejected into a suitable lead plate container 314 ready for transport. 10 The lead paste which collects in the bottom of lead paste collection tank 313 is passed through to sulphur removal and drying component 400 which comprises one or more treatment tanks 401 which contain a solution designed to reduce the sulphur levels of the lead paste, for example a caustic soda, potassium hydroxide or sodium hypochlorite solution. 15 Depending on the amount of lead paste and the sulphur levels therein all of the paste may be pumped into the first in the series of treatment tanks 401 and then on to subsequent tanks 401 until the sulphur levels have been reduced sufficiently. Alternatively, the lead paste pumped from collection tank 313 may be distributed evenly between all of the treatment tanks 401 20 and so a larger quantity of lead salts are treated simultaneously. The caustic soda, or like sulphur-reducing solution, is made up in reservoir 402 and the washings from third rotating auger 311, lead paste collection tank 313 and treatment tanks 401 are collected in washings reservoir 403 and may be re-used or passed on for waste treatment, as will 24 be described below. Once the sulphur levels have been reduced sufficiently the lead paste is pumped into a drying station which in the embodiment shown takes the form of filter press 404 which is driven by motor 405. Here the water and 5 salts from the sulphur treatment are separated from the lead paste, by a physical squeezing or pressing motion, which is then ejected as a substantially dry cake 406. This washed, dried and sulphur reduced lead paste is then ready for transport of further processing, such as smelting. The solutions used to treat and lower sulphur levels in the lead must 10 themselves be removed as waste after use. If, for example, caustic soda (sodium hydroxide) is used as the treatment solution then this will be transformed into sodium sulphate upon reaction with sulphurous compounds. The used solutions are pumped from various sources such as washings reservoir 403 into salt dehydration apparatus 500 which comprises a salt 15 processing unit 501 which may take the form of an evaporator, crystallizer or the like and may be used in combination with a heat pump 502 or the like. Salt processing unit 501 results in the removal of water from the salt solution and, depending on the process used, will leave the salt product as a powder or crystals which are subsequently introduced to salt container 504. 20 The dry salt product may have value as a chemical reagent. The sulphuric acid which collected in acid collection tank 307 is passed through to acid dehydration apparatus 600 which comprises a concentrator 601 (connections to tank not shown), if it is necessary to reduce its water content. Concentrator 601 may take the form of a vacuum still or 25 like evaporating apparatus with associated condenser 602, heater 603 and other peripheral devices which are well known in the art. The sulphuric acid is thus concentrated to the required level and so can be tailored and supplied to various industries for different applications. 5 It will be appreciated that the battery processing apparatus 100 described is fully automated from the moment the batteries are introduced until substantially pure plastic, lead plate, lead paste, sulphuric acid and salts such as sodium sulphates are produced. The apparatus is amenable at a number of points to remote monitoring by use of a number of sensors and a 10 central computer. For example, the number of batteries introduced, sulphur levels of the lead, content of sulphur reducing chemicals in the treatment solutions and moisture levels in the lead paste product can all be monitored. The apparatus shown in FIG 8 thus represents an extremely efficient and cost-effective way of dismantling lead-acid batteries and isolating the 15 components of value in a suitable form for sale or further use. The inventors have disclosed herein a method and apparatus for processing lead-acid batteries to enable one or more of the constituent parts to be isolated so as to allow value to be recouped from the used batteries. The need for a smelting operation has been avoided and hence the 20 constituent materials which are typically lost in such an operation are able to be collected and sold. It will be appreciated by the skilled person that the present invention is not limited to the embodiments described in detail herein, and that a variety of other embodiments may be contemplated which are, nevertheless, 26 consistent with the broad spirit and scope of the invention.

Claims

1. A method of isolating the constituent materials of a lead-acid battery including the steps of: (a) dismantling the battery; and (b) substantially separating the metallic and non-metallic constituents of the battery.

2. The method of claim 1 wherein the battery is dismantled by crushing and/or shredding.

3. The method of claim 1 further comprising the step of shredding the non-metallic constituents.

4. The method of claim 1 wherein the metallic and non-metallic constituents are separated by hand, by gravity or according to their relative density.

5. The method of claim 4 wherein the metallic and non-metallic constituents are separated according to their relative density in water or sulphuric acid.

6. The method of claim 1 wherein the metallic constituents comprise lead and/or lead salts which are separated from the non-metallic constituents without the need for a smelting operation.

7. The method of claim 1 wherein the non-metallic constituents comprise plastics which are obtained in substantially pure form. 28

8. The method of claim 1 further comprising the step of reducing the sulphur content of the metallic and/or non-metallic constituents of the battery.

9. The method of claim 8 wherein the metallic and/or non-metallic constituents of the battery are contacted with an alkali metal carbonate, alkaline earth metal carbonate, alkali metal hydroxide or alkali metal hypochlorite to reduce their sulphur content.

10. The method of claim 9 wherein the alkali metal hypochlorite is a sodium hypochlorite solution, the alkali metal hydroxide is a sodium hydroxide solution and the alkali metal carbonate is a sodium carbonate solution.

11. The method of claim 1 further comprising the step of reducing the moisture content of one or more of the metallic constituents.

12. The method of claim 11 wherein the moisture reduction is carried out by use of a centrifuge or a filter press.

13. The method of any one of the proceeding claims wherein one or more steps are automated.

14. An apparatus for use in isolating the constituent materials of a lead acid battery, the apparatus comprising a battery dismantling component and a separating component and wherein the constituent materials of the battery are released in the battery dismantling component and are then introduced into the separating component. 29

15. The apparatus of claim 14 further comprising a shredding component for diminution of non-metallic constituents.

16. The apparatus of claim 14 wherein the separating component comprises a gravity separation and/or a density separation.

17. The apparatus of claim 16 wherein the gravity separation is carried out using an angled vibrating table or a rotating auger.

18. The apparatus of claim 16 wherein the density separation is carried out in a volume of water and/or sulphuric acid.

19. The apparatus of claim 14 further comprising a treatment solution to reduce the sulphur content of one or more of the constituent materials of the lead-acid battery.

20. The apparatus of claim 19 wherein the treatment solution is an alkali metal hydroxide solution or a bleach solution.

21. The apparatus of claim 20 wherein the alkali metal hydroxide solution is a sodium hydroxide solution and the bleach solution is a sodium hypochlorite solution.

22. The apparatus of claim 14 further comprising a drying component to reduce the moisture content of one or more of the constituent materials of the lead-acid battery.

23. The apparatus of claim 22 wherein the drying component is a 30 centrifuge or a filter press.