A METHOD, APPARATUS AND SYSTEM FOR PROCESSING A COMPOSITE WASTE SOURCE

Abstract

A method, apparatus and system for processing a composite waste source, such as e-waste, is disclosed. The composite waste source may comprise low-, moderate and high-melting point constituents, such as plastics, metals and ceramics. The composite waste source is heated to a first temperature zone, causing at least some of the low-melting point constituents to at least partially thermally transform. The composite waste source is subsequently heated to a second, higher, temperature zone, causing at least some of the moderate-melting point constituents to at least partially thermally transform. At least some of the at least partially thermally transformed constituents may be recovered. The method, apparatus and system disclosed may provide for the recovery and reuse of materials which would otherwise be sent to landfill or incinerated.

Claims

1. A method of processing electronic waste comprising low-, moderate and high-melting point constituents, the method comprising: heating the electronic waste in a first temperature zone to a first temperature, such that at least some of the low-melting point constituents in the electronic waste are at least partially thermally transformed; and heating the electronic waste from the first temperature zone in a second, higher, temperature zone, to a second temperature such that at least some of the moderate-melting point constituents are at least partially thermally transformed, wherein at least some of the high-melting point constituents remain reasonably inert.

2. A method as claimed in claim 1 wherein the low-melting point constituents are at least partially thermally transformed by melting, alloy formation, dissolution and/or phase separation.

3. A method as claimed in claim 1 wherein the moderate-melting point constituents are at least partially thermally transformed by melting, alloy formation and/or dissolution.

4. A method of processing electronic waste the method comprising: rapidly heating the electronic waste in a first temperature zone to a first temperature, such that at least some of the plastic constituents in the electronic waste are at least partially thermally transformed; and heating the electronic waste in a second temperature zone to a second temperature, such that at least some metal constituents in the electronic waste are at least partially thermally transformed, wherein the ceramic constituents remain reasonably inert.

5. A method as claimed in claim 4 wherein the plastic constituents are at least partially thermally transformed into gases and solid carbon.

6-7. (canceled)

8. A method as claimed in claim 4 wherein the metal constituents are at least partially thermally transformed through melting, alloy formation and/or dissolution.

9. A method as claimed in claim 4 wherein, prior to rapidly heating the electronic waste to the first temperature zone, the electronic waste is pre-heated in a pre-treatment temperature zone to a pre-treatment temperature that is lower than the first temperature, whereby at least some low-melting point metals are at least partially thermally transformed to form metals or metal alloys.

10. A method as claimed in claim 4 further comprising the step of heating the electronic waste in at least one additional temperature zone to at least one additional temperature, wherein the temperature in the at least one additional temperature zone is a higher temperature than the preceding temperature zone.

11. A method as claimed in claim 4 further comprising collecting at least some of the at least partially thermally transformed constituents at the or each temperature zone.

12. A method as claimed in claim 4 wherein the temperatures in the zones are controlled so as to minimise the generation of hazardous materials.

13. A method as claimed in claim 4 wherein the method is conducted under inert conditions.

14. (canceled)

15. A method as claimed in claim 4 wherein the electronic waste is analysed to determine its constituents prior to heating.

16-20. (canceled)

21. A method of producing a metal alloy from electronic waste the method-comprising a multi-stage heating process including the steps of: rapidly heating the electronic waste to a first temperature in a first temperature zone, such that at least some plastic constituents in the electronic waste are at least partially thermally transformed; and heating the electronic waste to a second temperature in a second temperature zone, such that at least some metal constituents in the electronic waste are at least partially thermally transformed; wherein at least some of the metal constituents are transformed into metal alloys.

22. A method as claimed in claim 21 wherein, when the metal constituents include copper, the resulting metal alloy is a copper-based metal alloy.

23. A method as claimed in claim 21 further comprising the step of: heating the electronic waste to a third temperature in a third temperature zone, such that remaining copper in the electronic waste is melted, and the ceramic constituents remain reasonably inert.

24. A method as claimed in claim 21 wherein the plastic constituents are at least partially thermally transformed into gases and solid carbon, and assist in the reduction of any copper oxides present in the second, or third, temperature zones.

25. A method of recovering metals from a electronic waste the method comprising a multi-stage heating process including the steps of: rapidly heating the electronic waste to a first temperature in a first temperature zone, such that at least some plastic constituents and low-melting temperature metal constituents in the electronic waste are at least partially thermally transformed; and heating the electronic waste to a second temperature in a second temperature zone, such that at least some moderate-melting temperature metal constituents in the electronic waste are at least partially thermally transformed; wherein at least some of the low-melting and moderate-melting temperature metal constituents are recovered as molten metals and/or metal alloys.

26. A method as claimed in claim 25 further comprising the step of: heating the electronic waste to a third temperature in a third temperature zone, such that remaining copper in the electronic waste is melted and the ceramic constituents remain reasonably inert.

27-46. (canceled)

47. A method as claimed in claim 4, wherein the temperatures in the zones avoid a temperature range of about 350° C.-850° C.

48. A method of processing a composite waste source comprising low-, moderate- and high-melting point constituents, the method comprising: heating the composite waste in a first temperature zone to a first temperature, such that at least some of the low-melting point constituents in the composite waste are at least partially thermally transformed; and heating the composite waste from the first temperature zone in a second, higher, temperature zone, to a second temperature such that at least some of the moderate-melting point constituents are at least partially thermally transformed, wherein at least some of the high-melting point constituents remain reasonably inert, and wherein the temperatures in the zones avoid a temperature range of about 350° C.-850° C.

Description

BRIEF DESCRIPTION OF THE DRAWING

[0065] Notwithstanding any other forms which may fall within the scope of the method, apparatus and system as set forth in the Summary, specific embodiments will now be described, by way of example only, with reference to the accompanying drawing in which:

[0066] FIG. 1 shows a schematic micro-recycling furnace used in accordance with an embodiment of the method, system and apparatus disclosed; and

[0067] FIGS. 2A to 2G show the schematic micro-recycling furnace of FIG. 1 in use, in accordance with an embodiment of the method, system and apparatus disclosed.

DETAILED DESCRIPTION

[0068] A schematic diagram of a micro-recycling furnace 10, is shown in FIG. 1. The micro-recycling furnace 10 includes a conveyor belt 12 that allows a composite waste source to move from low to high temperature zones in the furnace. The micro-recycling furnace 10 also includes a receptacle 14, such as a hot working stage, to hold the composite waste source, although it should be appreciated that in some forms the composite waste source may be placed directly onto the conveyor belt 12, such as if the conveyor belt is a mesh, or if portions of the conveyor belt are a mesh or sieve.

[0069] The receptacle 14 may include a sieve or mesh base 16, which can allow molten materials to pass therethrough for collection and subsequent processing, if appropriate. The micro-recycling furnace 10 of FIG. 1 is shown having three recovery collectors 18, 20 and 22, for this purpose. It should be appreciated that there may only be two such collectors, or there may be additional such collecters (not shown).

[0070] The micro-recycling furnace 10 shown includes an automated motion system 24 to automatically operate conveyor belt 12, to cause it to move the receptacle 14 into different temperature zones within the furnace 10. It should be appreciated that the automation of the conveyor belt 12 may still be subject to specific parameters, such as conveyor belt speed, or length of time that the conveyor belt is to remain in a specific temperature zone, and that these parameters may be entered into a control program for the automated motion system. It should also be appreciated that in alternative forms, the conveyor belt 12 may be manually operated, thus eliminating the need for the shown automated motion system 24.

[0071] The micro-recycling furnace 10 is also shown having a gas scrubber 26, to remove gaseous releases generated during use of the furnace 10.

[0072] Reference is now made to FIGS. 2A to 2G, which show some exemplary sequential stages of the micro-recycling furnace 10 in use. FIG. 2A shows micro-recycling furnace 10 of FIG. 1, with a composite waste 30 on the sieve base 16 of receptacle 14, located in the low temperature zone of the furnace 10. After a period of time in the low temperature zone, and as shown in FIG. 2B, molten material 32 passes through the sieve base 16, and is collected in the first recovery collector 18.

[0073] The conveyor belt 12 then moves the receptacle 14 to a first position in the high temperature zone. The temperature in this first position is higher than the temperature in the low temperature zone. Because of the recovery of molten material 32, the volume of composite waste 30 has reduced, with the reduced volume of composite waste 30B shown in the receptacle 14 of FIG. 2C. After a period of time in this first position of the high temperature zone, and as shown in FIG. 2D, molten material 34 passes through the sieve base 16, and is collected in the second recovery collector 20.

[0074] The conveyor belt 12 again moves the receptacle 14 to a second position in the high temperature zone (see FIG. 2E). The temperature in this second position of the high temperature zone is higher than the temperature in the first position of the high temperature zone and higher than the temperature in the low temperature zone. After a period of time in this second position of the high temperature zone, and as shown in FIG. 2F, molten material 36 from the composite waste 30C passes through the sieve base 16, and is collected in the second recovery collector 22.

[0075] Once the recovery processes have completed, the conveyor belt 12 can again move the receptacle 14, with any other leftover materials 38 which did not melt at the selected temperature zones remaining in the receptacle 14. This leftover material 38 may also be collected, e.g. for discarding, disposal, or collection and further processing. The micro-recycling furnace 10 provides a safe and sustainable solution for processing composite waste that also contains toxic waste and metals.

[0076] Low melting-point materials, such as lead or tin, may form an alloy 32 or molten metal at relatively low temperature zones. It should also be appreciated that low melting-point materials, such as lead, may also form an alloy 34 at a relatively moderate temperature zone. For example, even though different lead alloys (such as lead-tin, or copper-lead) may form at a variety of temperatures (between about 250° C.-350° C., and 350° C.-1250° C., respectively), specific alloys may be preferred to remove lead from the system. For example, formation of lead-tin alloys at 250° C.-350° C. may be preferred to remove lead at a lower temperature and minimise the amount of lead in the system at higher temperatures, such as when the reactivity of copper is higher, or the possibility of lead vapourisation is higher. The removal and recovery of lead in alloyed form may, in this regard, reduce the potential environmental impact.

[0077] It should also be appreciated that in selecting the temperature zones, heating rates and time spent at various temperatures, one goal may be to remove a significant portion of e.g. lead at relatively low and moderate temperature zones, to recover leaded alloys separately and minimise the lead from becoming part of other alloys, such as copper, being recovered. In this regard, it may be necessary to increase the time spent at a particular temperature in a relatively low to moderate temperature zone in order to remove the majority of lead from the composite waste source. As such, the composite waste source may be judiciously selected so that sources with relatively higher lead contents (such as older-style printed circuit boards) are processed at the same time.

[0078] As will be readily understood by those skilled in the art, the rationale behind removing as much lead as possible in the low and moderate temperature zones is to minimise the amount of lead left in the composite waste source 30 when the furnace temperature is being increased to a temperature at which lead vapourises. However, as will also be appreciated by those skilled in the art, there are known scrubbing or capture techniques that can be employed to prevent such gases from escaping into the environment or atmosphere, should lead vapourise. For example, a gas scrubber 26 may be employed with the micro-recycling furnace 10 to remove gaseous releases generated during processing.

[0079] Another goal in selecting the temperature zones, heating rates and time spent at various temperature zones, may be to maximise the reactivity of, for example, copper. In this regard, the goal may be to prevent copper from melting out, so that if there is lead or tin in the system, they will form alloys with copper, such as the material recovered as material 34. By tailoring the temperature zone, the percentage of, for example, tin in the copper alloy can be altered.

[0080] Another goal in selecting the temperature zones, heating rates and time spent at various temperature zones, may be to minimise the production of toxic gases, such as dioxins and furans.

[0081] At moderate temperatures, plastics in the composite waste source will also continue to undergo phase transformations, with volatile and gaseous release, and solid carbon formation.

[0082] With further increases in temperature, high-melting point constituents, such as silica, in the form of glass fibers, will remain generally inert while any remaining copper will melt. In this regard, the copper will melt through the mesh/sieve base 16 of conveyor belt 12 as material 36, while the glass fibers will remain on top of the mesh conveyor belt, and be part of other leftover materials 38 which also did not melt at the selected temperature zones.

[0083] The leftover materials 38 can also be recovered, for disposal or for further use or processing. For example, if the leftover materials 38 are high in carbon, they may be employed as a carbon source for other metallurgical processes (such as ferro-alloy production or smelting). Even if the leftover materials 38 are unable to be used, the amount of leftover material 38 will be significantly less than the starting composite waste source 30, resulting in significantly less bulk material being sent to landfill.

[0084] Additionally, recovery of materials 32, 34 and 36 has allowed the reclamation of valuable resources which may be rare, expensive or otherwise pose an environmental risk. Furthermore, it is generally accepted that the recycling of metals and metal alloys is more energy efficient, and leads to reduced energy consumption in the manufacturing of metals when recycling is compared to the manufacture of metals from ores. In this regard, the method, system and apparatus disclosed herein may be considered to be a “micro-factory” for the creation of resources from waste, that provides a safe and sustainable solution for the localised processing and toxic composite waste that contains metals.

EXEMPLARY METHOD

[0085] A non-limiting exemplary method for the processing of a composite waste source will now be described with reference to FIG. 1. In this exemplary method, the composite waste source comprised a mixture of electronic components such as mobile (cell) phones, e-readers, DVD players and televisions. In order to increase the recovery of various metal alloys, it was determined that the covers and cases of the electronic components should be removed to minimise dilution of the metals during processing. In this regard, a fragmenter was used to pull the mobile (cell) phones, e-readers, DVD players and televisions apart to separate the plastic casings from the circuit boards and other recoverable componentry of the devices. The plastic casings were able to be recycled in a separate process, using known technologies.

[0086] The printed circuit boards and other recoverable componentry of the devices were then broken down into smaller chunks of board and componentry, forming the composite waste source 30. The composite waste source 30 was placed on the mesh base 16 of receptacle 14 on conveyor belt 12, and the first temperature zone was heated to about 325° C., and held at this temperature for about 60 minutes. A molten material 32 was observed to drip through the mesh base 16 of receptacle 14, and was collected in a first recovery collector 18.

[0087] After about 60 minutes, the conveyor belt 12 was moved so that the remaining composite waste source 30B was positioned in the second temperature zone. The temperature in the second temperature zone was rapidly increased to above about 900° C., and held at this temperature for about 30 minutes. The temperature was increased at a rate of about 50-100° C./min or greater, in order to minimise the production of dioxins and furans which occurs at temperatures between about 350-850° C. A molten material 34 was again observed to drip through the mesh base 16 of receptacle 14, and was collected in a second recovery collector 20 positioned in the second temperature zone. The formation of gases were also observed. The gas scrubber 26 removed the gases generated from the micro-recycling furnace 10 during the process.

[0088] After about 30 minutes, the conveyor belt 12 was again moved so that the receptacle 14 with the remaining waste source 30C was positioned in the third temperature zone. The temperature in the third temperature zone was increased to about 1100° C., and was held at this temperature for about 30 minutes. A molten material 36 was again observed to drip through the mesh base 16 of receptacle 14, and was collected in a third recovery collector 22 positioned in the third temperature zone.

[0089] Recovered materials 32, 34 and 36 were removed separately and taken for further processing to complete the recycling and refinement of the metal alloys. The leftover material 38 was also removed and processed to recover valuable materials.

[0090] It was observed that the disclosed solid-state process provided a simple method for the micro-recycling of composite waste sources, that didn't require the manual separation of many different types of materials or the use of smelting technologies of known processes. This process not only had the effect of providing a safe and sustainable solution for the recycling of toxic composite waste containing materials, it was also a micro-factory that allowed the creation and recovery of resources from that waste.

[0091] Whilst a number of specific embodiments have been described, it should be appreciated that the methods, apparatus and system may be embodied in many other forms. For example: modifications may be made to the heating rate used to heat the composite waste source to the desired temperature zone; a different type of furnace, such as a horizontal furnace, may be employed; the recovery of certain metals or metal alloys may be preferred, which may alter the preferred temperatures of the temperature zones; additional or fewer temperature zones may be employed, depending on which materials are being targeted for recovery; the length of time required at a specified temperature may vary, depending on which materials are being targeted for recovery or the constituents present in the composite waste source; etc.

[0092] In the claims which follow, and in the preceding description, except where the context requires otherwise due to express language or necessary implication, the word “comprise” and variations such as “comprises” or “comprising” are used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the method, apparatus and system as disclosed herein.