GB2404197A

GB2404197A - Compressed and bound waste material

Info

Publication number: GB2404197A
Application number: GB0317216A
Authority: GB
Inventors: Mirza Nizam Baig
Original assignee: Individual
Current assignee: Individual
Priority date: 2003-07-23
Filing date: 2003-07-23
Publication date: 2005-01-26
Also published as: GB0317216D0

Abstract

A method for the recycling of a waste material, the method comprising: <SL> <LI>(a) placing the waste material in a compression device; <LI>(b) compressing the waste material; <LI>(c) binding the compressed waste material with binder material; <LI>(d) transferring the bound compressed waste material to a container; <LI>(e) adding at least one curable filler material to the container; and <LI>(f) causing the at least one curable filler material to cure. </SL> Preferably the waste material comprises vehicle tyres. Optionally, the waste material comprises an additional waste material which may comprise, for example, dry batteries, mobile telephones, CFC-contaminated insulation, or asbestos insulation. The binder material preferably comprises polymeric or metal straps or bands. The filling material is preferably cement. The cured waste material produced by means of the method of the invention is obtained in the form of blocks which can be used, for example in the construction of buildings, roads, composting and storage pens, embankments, sea defence structures, erosion barriers and other defences on river and canal banks, and high security fences and barriers.

Description

2404 1 97

WASTE RECYCLING PROCESS

This invention relates to a novel concept and process for the recycling of waste materials, which allows for the significant disposal problems which are currently encountered, and are certain to increase in the future, to be overcome. Specifically, the invention concerns a process for the recycling of vehicle lyres of various dimensions.

The generation of waste has become of increasing concern in recent years, as volumes of materials for disposal have grown markedly, and this trend is set to continue in the future, with the certainty that the problems which it creates will become much more severe. Specifically, the requirement for disposal of materials which are not biodegradable has become particularly acute. The position is made more urgent by the increasingly stringent demands of environmental legislation, which requires that ever more care is taken in the disposal of waste materials in order to minimise damage to the environment. For example, it is clear that the ability to rely on disposal to landfill sites will continue to markedly decrease in the coming years. Consequently, alternative methods of disposal are constantly being sought by the waste disposal industry in the light of, for example, Directives from the European Union and National Legislation in the United Kingdom and other countries.

Of especial concern is the disposal of resilient non-biodegradable materials such as rubber, most particularly synthetic rubber materials, such as the compositions found in vehicle lyres. Modern tyres are typically manufactured from synthetic rubbers and carbon, generally in the approximate ratio of 40% rubber to 60% carbon, and these materials are inherently tough and durable, which is necessarily the case in view of their intended use, and the stringent safety considerations that have to be observed with such products. The nature of these materials presents particular challenges to waste disposal experts and these challenges will increase massively as the number of vehicles in use on the roads continues to expand at such a rapid rate. Consequently, the requirement to find a solution to the problem becomes ever more urgent.

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c e c c; c c ce Legislation in the European Union has decreed that the disposal of whole tyres in landfill sites is prohibited in member states from 15 July 2003, whilst similar provisions will apply to crumbed lyres, which result from degradation of used lyres, from 2006.

The major problems associated with the disposal of tyres in landfill sites have included pollution and contamination of nearby ground water, aquifers, rivers, canals and sump tanks. Similar difficulties have been encountered with other waste materials, including, for example, batteries and devices which incorporate batteries, such as mobile telephones and wristwatches, and insulation from refrigerators and freezers, which may be contaminated with chlorofluorocarbons. In addition, materials such as horsehair and asbestos, previously used as insulating materials, present evident hazards.

Naturally, it would be highly preferable if any method for the disposal of waste materials of this type could, in addition to providing a safe and effective means of disposal, also involve the recycling of the materials for a useful purpose. In other words, the optimum solution would provide a process for treatment of the waste materials which resulted in the production of a recycled material which could then be utilised for some other purpose. It would be particularly desirable if the material so formed was found to be more suitable for a specific purpose than the materials of the prior art, since the process would thereby have assisted in the solution of a problem

in a different field.

Consequently, the present invention seeks to provide a process for the disposal of waste materials which also facilitates the recycling of the waste materials into a useful form for application in various other fields. More specifically, the invention seeks to provide a method for the recycling of used and worn vehicle lyres which allows for the production of a recycled material which is environmentally safe and has useful practical applications. À ..

À . À À e À À À À e i Thus according to a first aspect of the present invention, there is provided a method for the recycling of a waste material, the method comprising: (a) placing the waste material in a compression device; (b) compressing the waste material; (c) binding the compressed waste material with binder material; (d) transferring the bound compressed waste material to a container; (e) adding at least one curable filler material to the container; and (f) causing the at least one curable filler material to cure.

The cured waste material produced by means of this process is obtained in the form of blocks having high strength and durability characteristics. Consequently, the blocks have potential applicability in a wide range of end uses, for example in the construction of buildings, roads and other structures for which such physical properties are essential. Specific examples include warehouses and other industrial buildings, composting and storage pens, embankments, sea defence structures, erosion barriers and other defences on river and canal banks, and high security fences and barriers.

Preferably, the waste material utilised in the process comprises rubber. More preferably, the rubber comprises at lease one synthetic rubber. Especially preferably the rubber comprises synthetic rubber and carbon. Most preferably, the rubber is in the form of synthetic rubber and carbon comprised in vehicle lyres, specifically worn and used tyres intended for disposal. Hundreds of millions of lyres have been illegally dumped over previous decades, and the long term degradation of these lyres has caused problems due to the release of toxic materials which can be leached into the soil, and thence into water courses, subterranean water flows, rivers and streams.

In addition, many of these dumps have caught fire, with the results that uncontrolled emissions of various toxins have occurred, often over prolonged periods, to the atmosphere as well as to the ground. Examples of the sorts of materials which are generated include dioxins, and heavy metals, as well as contaminated dust. À .e

À À À À e À À À e e The method of the invention also envisages the optional inclusion of further waste materials in the material for disposal. Most particularly, said additional waste material may comprise at least one of the following: (i) Dry batteries containing lithium, mercury or other heavy metals; (ii) Discarded mobile telephones incorporating inbuilt dry batteries; (iii) Microchip battery cells as found in, for example, quartz watches; (iv) Insulation contaminated with chlorofluorocarbons as found in, for example, refrigerators and freezers; and (v) Horsehair and asbestos insulation from demolished buildings.

The compression device typically comprises a heavy duty press of the sort which are widely commercially available, for example a 400 tonne hydraulic press. A suitable] example of such a device is a Rugerini 400 tonne compression remote controlled variable hydraulic press, which is adapted for vertical or horizontal mounting.

Following compression of the waste material, the binding process involves the application of a binder material to ensure the compressed mass of waste material is held together as a discrete unit for further processing. This may be most conveniently achieved by the application of straps or bands comprised of a suitably strong material around the compressed mass. Preferred materials for this purpose include metals such as steel, or various synthetic polymers, typically, for example, polyesters.

A typical binding process employs a plurality of straps or bands, and the effectiveness of these straps or bands may be further enhanced if they are physically t attached to each other. Thus, it is preferred that the binding material should be subjected to a treatment which causes such attachments to occur. As examples of such treatments could be mentioned friction welding of polyesters, with the welds set at I tonne pressure, and high pressure clamp crinkling of the ends of metal bands. À .. À e À e

The number of straps or bands employed is determined by simple practical considerations but, for the size of compressed mass obtained from around 60 or 70 car lyres, roughly 8 to 12, typically 9 or 10, polyester bands or straps could be employed. In the case of steel, the number of bands for a similar application could be reduced to around 3 or 4. The bands or straps have dimensions suitable to allow them to satisfactorily perform their intended function. In other words, they must satisfy the necessary criteria of strength and resilience. For both polyester and metal binding materials, suitable straps or bands typically have a width of between 15 and mm and a thickness in the region of 0.8 to 1.2 mm; specific example would be bands of 19 mm width and I mm thickness, used for the binding of compressed masses obtained from 50-70 car lyres. Suitable incremental adjustments of the numbers and dimensions of bands can be applied, as appropriate, in the case of larger i tyre bales, obtained from, for example, as many as 100 lyres. ] Following the binding process, the compressed unit or bale may then be transferred to a container for completing the filling and curing processes by any convenient means, such as a hoist, conveyor or fork lift truck. Suitable containers are any of convenient size into which the unit may be placed, and the said containers may be constructed from any of a wide range of convenient materials, including metals such as steel, various plastics, or wood. The curable filler material is added to the said container after the compressed material has been placed therein.

The curable filler material is intended to give the final block the strength and durability to ensure that it is suitable for application in a wide range of end uses, as previously outlined. In addition, it is vital that the block should demonstrate a range of other desirable properties, most particularly resistance to degradation by ultra- violet rays in solar radiation, prevention of leaching from the encased waste materials, and fire resistance. Thus, the selection of the curable filler material is vital to the eventual success of the process. A particularly suitable curable filler material comprises cement, which may conveniently be mixed with water, poured into the container, and allowed to cure to produce a block of recycled waste material. Any À ee.

À : À r À . . À .. À À À: À . . . À À commercially available cement is suitable for this purpose, for example Portland Cement.

As is well known, of course, the strength of cured cement may be greatly enhanced by the addition of suitable additional filler materials, which may either be curable or inert. Typically, much improved performance may be achieved by the inclusion of an inert material such as sand, and this is also true of the present invention. Thus, in a preferred embodiment of the present invention, the at least one curable filler material additionally comprises at least one inert filler material. Preferably said at least one l 0 inert filler material comprises sand.

Particularly favourable results are achieved with the present invention by the further addition of other inert filler materials capable of providing increased strength, robustness and durability in the final cured block. Especially preferred in this regard are pebbles, gravel, crushed glass or polymer fibres admixed with bitumen, all of which are found to significantly increase the strength of the block. Excellent performance has been achieved with blocks obtained from the incorporation of gravel particles of 5-20 mm diameter, with particles of around 10 mm diameter being most favoured in this regard.

Following addition of the at least one curable filler material, optionally including additional curable or inert filler materials, the contents of the container are preferably caused to mix more intimately prior to curing. This mixing process may, for example, be assisted by stirring or, more preferably, by vibration of the contents, typically using an electric rod vibrator.

Curing of the at least one curable filler material is generally achieved by allowing the material to set, although other curing methods may be employed, if appropriate. In the case of cement, however, it is generally sufficient to allow the contents of the container to stand for a suitable length of time until curing is achieved. Typically, À . c c.

À e, À , . À À À À this would be between 24 and 96 hours, with particularly satisfactory results generally being achieved by employing a curing time of around 72 hours.

It is possible to manufacture blocks of different sizes according to the method of the invention by adjusting the number and size of lyres included in the compression process. Clearly, it is preferable to use larger lyres, for example from lorries, for producing larger blocks. Smaller blocks may either be produced from car lyres or, alternatively, may be manufactured by using a lesser number of larger lyres. As a general guide, typical blocks are produced from between 50 and 100 car lyres.

The optimum size of block is manufactured from around 60 or 70 car lyres. In such a case, the compressed bale obtained before addition of the at least one curable filler material would typically have dimensions of around 1.0 x 1.0 x 0.7 m and weigh in the region of 300 kg. Following addition of the at least one curable filler material, and after completion of the curing process, the final block produced from such a bale 5 would have consistent dimensions of around 1.25 x 1.25 x 0.8 m and a weight of about 1.75 tonnes.

The blocks produced according to the method of the invention have been shown in testing to demonstrate extremely high strength and durability. Consequently, they are suitable for use as building materials, and for the various alternative applications previously outlined. Hence, further aspects of the invention relate to the blocks as produced by the method of the invention, and to the use of the blocks as hereinbefore described. A still further aspect of the invention also envisages the use of waste materials in the production of blocks by the method of the invention.

Claims

À:e:.e À.e À :.. CLAIMS

1. A method for the recycling of a waste material, the method comprising: (a) placing the waste material in a compression device; (b) compressing the waste material; (c) binding the compressed waste material with binder material; (d) transferring the bound compressed waste material to a container; (e) adding at least one curable filler material to the container; and (f) causing the at least one curable filler material to cure.

2. A method as claimed in claim 1 wherein the waste material comprises rubber.

3. A method as claimed in claim 2 wherein the rubber comprises at least one synthetic rubber.

4. A method as claimed in claim 2 or 3 wherein the rubber comprises synthetic rubber and carbon.

5. A method as claimed in claim 4 wherein the rubber is in the form of synthetic rubber and carbon comprised in vehicle lyres.

6. A method as claimed in any one of claims 2 to 5 wherein the waste material additionally comprises at least one additional waste material.

7. A method as claimed in claim 6 wherein the at least one additional waste material is chosen from the following: (i) Dry batteries containing lithium, mercury or other heavy metals; (ii) Discarded mobile telephones incorporating inbuilt dry batteries; (iii) Microchip battery cells; À:. :.. À... :..

(iv) Insulation contaminated with chlorofluorocarbons; and (vi) Horsehair and asbestos insulation.

8. A method as claimed in any one of claims 5, 6 or 7 wherein the tyres comprise car lyres.

9. A method as claimed in claim 8 wherein the number of car lyres placed in the compression device is between 50 and 100.

10. A method as claimed in claim 9 wherein the number of car tyres placed in the compression device is between 60 and 70.

11. A method as claimed in any preceding claim wherein the compression device comprises a heavy duty press.

12. A method as claimed in claim 11 wherein the heavy duty press comprises a 400 tonne hydraulic press.

13. A method as claimed in any preceding claim wherein the binding process involves the application of a binder material to the compressed waste material. f

14. A method as claimed in claim 13 wherein said binder material comprises straps or bands comprised of material.

15. A method as claimed in claim 13 or 14 wherein the binder material comprises a synthetic polymeric material.

16. A method as claimed in claim 15 wherein the synthetic polymeric material comprises at least one polyester.

ÀÀ. e À ee À À À À À e À . À À À. À e

17. A method as claimed in any one of claims 14 to 16 wherein the binder material is subjected to a friction welding treatment.

18. A method as claimed in claim 13 or 14 wherein the binder material comprises a metal.

19. A method as claimed in claim 18 wherein the metal comprises steel.

20. A method as claimed in claim 18 or 19 wherein the binder material is subjected to a high pressure clamp crinkling treatment. ?

21. A method as claimed in any one of claims 14 to 20 wherein said straps or bands have a width of between 15 and 25 mm and a thickness in the region of 0.8to 1.2 mm.

22. A method as claimed in any one of claims 14 to 21 wherein the number of straps or bands is in the range from 3 to 12.

23. A method as claimed in any preceding claim wherein said at least one curable filler material comprises cement.

24. A method as claimed in claim 23 wherein said cement is mixed with water prior to pouring into the container.

25. A method as claimed in any preceding claim wherein said at least one curable filler material additionally comprises at least one inert filler material.

26. A method as claimed in claim 25 wherein said at least one inert filler material comprises at least one of sand, pebbles, gravel, crushed glass and polymer fibres admixed with bitumen.

À À. a À a À À a À a À À À À À .e À a

27. A method as claimed in claim 25 or 26 wherein said at least one inert filler material comprises sand and at least one of pebbles, gravel, crushed glass and polymer fibres admixed with bitumen.

28. A method as claimed in claim 26 or 27 wherein said pebbles or gravel have a particle diameter of 5-20 mm.

29. A method as claimed in claim 28 wherein said particle diameter is in the region of 10 mm.

30. A method as claimed in any preceding claim wherein the contents of the container are caused to mix prior to curing.

31. A method as claimed in any one of claims 23 to 30 wherein the contents of the container are allowed to stand for a suitable length of time until curing is achieved.

32. A method as claimed in claim 31 wherein said length of time is between 24 and 96 hours.

33. A method as claimed in claim 32 wherein said length of time is around 72 hours.

34. A method substantially as herein described and with reference to the

accompanying description.

35. A block comprising waste material whenever produced by a method as claimed in any one of claims I to 34.

36. The use of at least one waste material in the production of a block by means of a method as claimed in any one of claims I to 34.

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