WO2017059497A1

WO2017059497A1 - Processing waste materials

Info

Publication number: WO2017059497A1
Application number: PCT/AU2016/050945
Authority: WO
Inventors: Matthew James ACTON; Daniel Philip WADDINGTON
Original assignee: Biocoal Group Pty Ltd
Current assignee: Biocoal Group Pty Ltd
Priority date: 2015-10-08
Filing date: 2016-10-07
Publication date: 2017-04-13
Anticipated expiration: 2018-04-08

Abstract

A method of manufacturing a product that substantially comprises plastics material from a co-mingled waste feed material includes the following steps: (a) shredding the waste feed material; (b) separating the shredded plastics waste feed material and the other shredded waste feed material based on size and forming a plurality of process streams, with one stream being predominantly waste plastics material; and (c) further processing the one process stream to remove "contaminants" and producing the substantially plastics material product.

Description

PROCESSING WASTE MATERIALS

TECHNICAL FIELD

The present invention relates to processing waste materials and producing valuable end-use products .

The present invention relates particularly, although by no means exclusively, to a method of manufacturing a valuable end-use product in the form of a plastics material product from a co-mingled waste feed material, as described herein.

The present invention also relates particularly, although by no means exclusively, to a plant for

manufacturing a valuable end-use product in the form of a plastics material product from a co-mingled waste feed material .

The present invention also relates particularly, although by no means exclusively, to a composite product that includes the above-described plastics material product and another carbon-bearing material that is suitable for use in high temperature processes . One example of a high temperature process is a metallurgical process , such as a steel making process in a steel making furnace . Other examples of high temperature processes are processes that are carried out in power stations and kilns, such as cement making kilns, which require heat to be generated by fossil or engineered fuels.

The present invention also relates particularly, although by no means exclusively, to a method of

manufacturing the composite product.

manufacturing the composite product. BACKGROUND ART

There are substantial volumes of waste materials produced each day in Australia and other countries from discarded products, including but not limited to packaging made from plastics materials, paper and metals, and composites of these materials. The discarded packaging includes, by way of example only, cardboard cartons, disposable bags made from films of plastics materials, and bottles and containers made from plastics material.

A proportion of the waste materials are recycled and re-used in the production of new products .

A further proportion of the waste materials are processed to become a refuse-derived fuel ("RDF") or a higher calorific solid recovered fuel ("SRF") .

The term "refuse-derived fuel" is understood herein to mean a fuel produced by shredding and dehydrating solid waste eed material . RDF consists largely of combustible components of municipal waste material .

The term "solid recovered fuel" is understood herein to mean a higher calorific category of the broader term refuse-derived fuel .

However, a significant proportion of the waste materials are used as land fill , and this is a loss of significant potential economic value for the waste materials .

The present invention makes it possible to obtain higher economic value for waste materials than is possible at the moment.

By way of particular example, the present invention provides an opportunity to process waste materials and produce a product that is substantially a plastics material . By way of further particular example, the present invention provides an opportunity to use the substantially plastics material product as a component of a composite of the plastics material and another carbon-bearing material which is suitable for use as a source of energy and as a reductant in pyrometallurgical processes carried out in metallurgical furnaces .

The above description is not to be taken as an admission of the common general knowledge in Australia or elsewhere.

SUMMARY OF THE DISCLOSURE

The focus of the present invention is on producing a substantially plastics material product from a co-mingled waste feed material.

The present invention provides a method of

manufacturing a product that substantially comprises plastics material from a co-mingled waste feed material that includes the following steps :

(a) shredding the waste feed material;

(b) separating the shredded plastics waste feed material and the other shredded waste feed material based on size into a first process stream that is predominantly plastics material and at least a second process stream that is a mixture of waste plastics material and other waste feed materials such as paper; and

(c) further processing the first process stream to remove "contaminants" and producing the substantially plastics material product.

The applicant has found that the shredding step is important in terms of "conditioning" the waste feed material for downstream size separation. In particular, the applicant has found that shredding has a different impact on plastics materials (such as in the form of plastic material bags and plastics bottles and other containers) and paper-based materials and other feed materials. More particularly, the applicant has found that there is a greater tendency for waste plastics materials to shred into larger pieces than the non-plastics material component of the waste material . The applicant has found that this impact of shredding on the waste material is particularly the case when waste material is subjected to a coarse shredding step.

In addition, the applicant has found that there is a threshold size above which a majority of the shredded material will be plastics material and below which there is a mixture of plastics material and other waste

materials such as paper. This segregation of shredded material is advantageous in separating plastics material from other waste material .

The threshold size is not an absolute value and varies depending on the characteristics of the waste feed materials.

By way of example, in one embodiment of the

invention, the threshold size is 60mm.

More generally, in other (although not the only other) embodiments of the invention, the threshold size is a size in a range of 50-70mm, tyically in a size in a range of 55-65mm.

The size separation step makes it possible to create a first process stream that is predominantly plastics material, i.e. a comparatively pure stream with respect to plastics materials. The first process stream is then further processed to remove what are "contaminants" from the perspective of the end product, i.e. the substantially plastics material product. More particularly, the term "contaminants" is a relative term. A material that is regarded as a

"contaminant" in terms of a particular product, such as the substantially plastics material product, may be an otherwise valuable material. Aluminium and other metals are examples .

The further processing steps for the first process stream may include an optical sorting to remove fibrous material and selected plastics materials, such as PVC, that are not required for the substantially plastics material product .

The further processing steps for the first process stream may include eddy current sorting to remove non- ferrous metals .

The further processing steps for the first process stream may include magnetic sorting to remove magnetic material .

The further processing steps for the first process stream may be carried out in any suitable sequence and the invention is not confined to the above sequence of steps.

The method may include further processing the second process stream, which is a mixture of waste plastics material and other waste feed materials such as paper, and producing an end-use product in the form of refuse-derived waste material that can be used as an energy source in cement kilns and other applications .

The further processing steps for the second process stream may include optical sorting to remove fibrous material and selected plastics materials that are not required for the substantially plastics material product.

The further processing steps for the second process stream may include eddy current sorting to remove non- ferrous metals, such as aluminium. The further processing steps for the second process stream may be carried out in any suitable sequence and the invention is not confined to the above sequence of steps .

The method may include a magnetic separation step for separating magnetic material from the waste feed material before shredding step (a) .

The method may include a primary sorting step to remove gross contamination, such as large metal pieces, and items that are not desired in output products of the method or that may damage equipment used for downstream method steps prior to the magnetic separation step. The primary sorting step may be a single step . The primary sorting step may be a plurality of steps.

The term "co-mingled waste feed material" is

understood herein to mean in the context of the invention any waste material that includes waste plastics materials and at least one other type of waste material from the group comprising waste paper, waste metals (ferrous and non-ferrous) , waste wood and other waste organic material, and waste inorganic material.

The co-mingled waste feed material may be obtained from any suitable source.

The co-mingled waste feed material may be obtained from a commercial materials recovery facility ("MRF") that receives and processes waste materials (for example by separating the materials into different categories) , and prepares recyclable materials for end-use manufacturers . Alternative terms for a materials recovery facility are materials reclamation facility and materials recycling facility.

The materials recovery facility may process municipal waste including domestically-sourced recyclable waste materials. The materials recovery facility may process industrially-sourced recyclable waste materials.

The co-mingled waste feed material may include waste plastics material in the form of films or bottles or other containers made from plastics materials .

The co-mingled waste feed material may be obtained from a paper mill .

The paper mill waste may include paper mill rejects, such as hydro-puled paper and plastics materials

(associated with the paper) that cannot be used for new paper production.

The method may produce other end-use products in addition to the substantially plastics material.

The other products may include metal .

The other products may include refuse-derived fuel

(RDF) .

The substantially plastics material product may comprise at least 80 wt.% plastics material.

The substantially plastics material product may comprise at least 85 wt.% plastics material.

The substantially plastics material product may comprise at least 90 wt.% plastics material.

The substantially plastics material product may comprise at least 95 wt.% plastics material.

The plastics material may be any one or more than one of PVC, low density polyethylene, high density polyethylene and polypropylene.

The present invention also provides the substantially plastics material product manufactured by the above- described method.

The product may be in any suitable form. For example, the product may be compressed into block-shaped bags. The present invention also provides a plant for manufacturing a product that substantially comprises plastics material from a co-mingled waste feed material , with the plant comprising:

(a) a shredder for shredding the waste feed

material ;

(b) a separator for separating the shredded waste plastics material and the other shredded waste feed materials based on size into a first process stream that is predominantly plastics material and at least a second process stream that is a mixture of plastics material and other feed materials such as paper; and

(c) any one or more than one of an optical sorter, an eddy current sorter and a magnetic sorter to remove

"contaminants" from the first process stream to produce the substantially plastics material product.

The plant may include other types of sorters for the first process stream as required given the make-up of the waste material in the first process stream.

The plant may include any one or more than one of an optical sorter, an eddy current sorter and a magnetic sorter to remove "contaminants" from the second process stream to produce the substantially plastics material product .

As mentioned above, the term "contaminants" is a relative term. A material that is regarded as a

The plant may include other types of sorters for the second process stream as required given the make-up of the waste material in the second process stream. The end-use application for the substantially plastics material product may be as a component in a composite product for use in a metallurgical furnace, such as an electric arc furnace, and is described as a "polymer charge carbon", that comprises the plastics material product and another carbon-bearing material . The other carbon-bearing material may comprise any one or more of rubber, coal, coke, char, and graphite. By way of example, the carbon-bearing material may comprise any one or more than one of rubber, coke fines, char fines, and coal fines . The plastics material product may act as a binder for the other carbon-bearing material in the composite product. In a metallurgical process, such as a steel making process, the carbon in the composite product may act as a source of energy and/or as a reductant. In addition, the carbon may act as a slag foaming agent.

A composite product described above, a method of manufacturing the composite product, and the use of the composite product in a metallurgical furnace is described in International application PCT/AU2011/000960 (WO

2012/019216) in the name of the OneSteel NSW Pty Limited and the entire disclosure in the International application is incorporated herein by cross-reference.

More particularly, the International application discloses a method of manufacturing a composite product for use in methods carr out in m allu g cal furnaces t. high temperatures of at least 400 C . The composite product substantially comprises (a) a recycled polymeric material that acts as a binder selected from a plastics material such as recycled low density polyethylene, recycled high density polyethylene, and recycled

polypropylene and (b) a carbon-bearing material selected from any one or more than one of rubber, coke, char, and coal , with the amount of the polymeric material comprising greater than 10 wt.% of the product. The method of manufacturing the composite product comprises mixing and heating the components of the composite product at the same time or sequentially and thereafter forming the heated mixture into a final product shape such as in the form of pellets, granules, blocks, pigs, patties, plugs, or pucks. The heating step melts at least a part of the plastics material to facilitate forming the product.

Typically, the product is a non-porous product that is at least substantially waterproof and comprises a continuous network of the plastics material and a uniform dispersion of the carbon-bearing material. Typically, the product is formed to have sufficient strength and toughness to be able to be handled within high temperature processing plants and to be charged into metallurgical furnaces in the plants without significant breakdown of the product into smaller sized products. Typically, the product is formed to be sufficiently large and have required

mechanical properties such as strength to withstand high temperatures and reactive conditions in metallurgical furnaces to facilitate controlled dissolution of the product in the furnaces over required time periods .

The present invention also provides a method of producing a composite product for use in a metallurgical furnace that comprises mixing and heating the above- described substantially plastics material and another carbon-bearing material at the same time or sequentially and thereafter forming the heated mixture into a final product shape of the composite product, with the heating step melting at least a part of the plastics material to facilitate forming the product.

The forming step may be an extrusion step . The final product shape may be pellets, granules, blocks, pigs, patties, plugs, or pucks.

The present invention also provides the composite product manufactured by the above-described method.

The present invention also provides a plant for manufacturing the composite product.

BRIEF DESCRIPTION OF THE DRAWING

The present invention is described further by way of example only with reference to the accompanying drawings of which:

Figure 1 is a diagram that illustrates one embodiment of a plant and a method of manufacturing a product that substantially comprises a plastics material from a co- mingled waste feed material; and

Figure 2 is a diagram that illustrates one embodiment of a plant and a method of manufacturing a composite product that comprises the plastics material product manufactured in the method shown in Figure 1 and another carbon-bearing material.

DESCRIPTION OF EMBODIMENT

The manufacturing plant and the associated

manufacturing method of the embodiment of the present invention described below with reference to the drawings comprises two operating units .

One unit produces a substantially plastics material product, which is the main focus of this unit, and other refuse-derived products including refuse-derived fuels, from a co-mingled waste feed material. The other unit produces a composite product of the plastics material product and another carbon-bearing material . The plant may be operated as an integrated plant with the substantially plastics material product of the first unit being supplied directly into the second unit to produce the composite product.

Alternatively, the units may be operated

independently and, for example, may be in different locations. In this alternative option, the plant produces at least two products , one of which is the substantially plastics material product and the other of which is the composite product. The products also include refuse- derived products .

It is noted that the invention is not confined to the use of the substantially plastics material product in the manufacture of the composite product.

The basic steps of the method of manufacturing the substantially plastics material product from a co-mingled waste feed material is as follows:

(a) shredding the waste feed material;

(b) separating the shredded waste plastics material and the other shredded waste feed material based on size into a first process stream that is predominantly plastics material and at least a second process stream that is a mixture of plastics material and other feed materials such as paper; and

(c) further processing the first process stream to remove "contaminants" and producing the substantially plastics material product, i.e. a plastics material product that comprise at least 95 wt.% plastics material. Unit (the "first unit") for producing the plastics material product

The following description is in the context of a co- mingled waste feed to the plant that is sourced from two very different waste streams from different sources , namely a coarse rejects waste material from a paper mill (see item 1 below) and a mixed rejects waste material from a materials recycling facility (see item 2 below) .

It is noted that the present invention is not confined to the use of these waste materials from these or other sources .

1. Paper plant rejects feed material to the first unit

This material is hydro-pulped paper and plastics materials (associated with the paper) that cannot be used for new paper production and in this embodiment has the following components .

2. Materials recovery facility (MRF) feed material to the first unit.

The rejects waste material from the materials recycling facility has the following components in this embodiment . MRF Rejects % SRF plant Recycled Product output

Plastics 35 38

Paper 12 13

Inert 3.4 Recycled

Steel 3 Recycled

Other metals 2 Recycled

Other 40 44

material

Wood 4 5

The amount of reject waste material from the

materials recovery facility to the first unit represents 54% of the total feed mix and the paper mill rejects to the first unit represents 46% of the total feed mix.

In addition, 91% of the materials recovery facility rejects are made into useful output products in the first unit and 64% of the paper mill rejects product is made into useful output products in the first unit.

The outputs from the first unit include the following materials :

• Plastics materials .

• Inert materials including glass.

• Aluminium (non-ferrous metals) .

• Steel (ferrous metals) .

• Fuels — fines, PVC and fibres.

• Hazardous material .

The first unit operates to process 4.9 tph of materials recovery facility rejects products and 3 tph of paper mill rejects products. The waste feed materials are 94% recycled material. 20% of the products from the first unit are recycled (e.g. the aluminium) and the remaining products from the first unit are a plastics material product. The total recycling that occurs in the first unit is over 95% and it is just 5% residuals that are being used as a fuel .

With reference to Figure 1, in the first unit the in- feed waste material is transported from storage bins (not shown) on an in-feed system and then onto a separate conveyor system and is transported past a series of operation stations, as summarised below.

Infeed System

The in-feed system is a 2400 mm wide steel slat chain conveyor with flat loading section. The flat area allows for 100m³ of feed material to be loaded onto it. This approximates to 10 tonnes of paper mill rejects products and 7 tonnes of materials recovery facility (MRF) products based on the feed rates described above .

1. Primary Sort of Material — item 3 in Figure 1

The purpose of this step 3 is to remove gross contamination, such as large metal pieces, and items that are not desired in the output products of the first unit or that may damage equipment in the plant. This primary sort step is the only step that requires manual

intervention in the whole process .

2. Magnetic Separation - item 5 in Figure 1

The shredded waste material is fed under magnetic belt separators to remove magnetic material from the waste material .

3. Shredder - item 7 in Figure 1 The primary sorted waste material is transferred to the shredder 7. The shredding operation is designed as a "coarse" shredding step to break up and liberate the in- feed material so that it can be effectively sorted by the downstream equipment. The term "coarse" in the context of shredding is well understood by persons in the industry. In the described embodiment, shredding is maximised at around 10 tph. One shredder option is a GENOX 2400 shredder capable of managing 10 tph waste materials .

4. Primary screen - item 9 in Figure 1

The shredded waste feed material is then transferred to a primary screen 9 and separated into a fines fraction (i.e. —10 mm) , a 10-60 mm middlings fraction, and a +60 mm large fraction.

The selection of the threshold of 60 mm for the 10- 60mm fraction and the +60mm fraction is based on an assessment of the characteristics of the feed waste material and an objective of having the larger size fraction as a substantially "pure" stream with respect to plastics material .

The 10-60mm fraction and the +60mm fraction are processed as described in item 5 onwards .

The fines fraction is bagged and sold as a refuse derived fuel (RDF) 11 for example for use in cement kilns.

One option for the primary screen is an IFE Variomat Screen. This screen has advantages compared to other screens such as ballistic separators, trommels and metal disc screens in the context of this embodiment of the invention. However, these other screens are options for other embodiments . The advantages of the IFE Variomat Screen for this embodiment are as follows: • Screening area to footprint - unlike a trommel the whole screen is providing effective screening and therefore has great efficiencies for its foot print. The screen provides 24m³ of screening area for a 24m³ foot print a trommel would require up to 2.5 times more footprint to get the same screening result.

• Ease of Maintenance - the screen is a downhill running vibratory type screen, with all parts external and easily accessible. This is a major advantage to the likes of a ballistic screen that in our experience need strip down even for simplistic cleaning. Reduction in blinding, the reverse rake louver type deck and the downhill flow of material means that the screening apertures are not prone to blinding (like all the other screens listed) . In addition the screen can be cleaned during operation, without loss of production. Screen sizes can be easily changed so that apertures can be adjusted to suit the waste stream.

The fines fraction (-10mm) is achieved using an IFE Trisomat screen. The screen works by oscillating in a rotary manner at a high speed. This oscillation causes neoprene decks to flip up and down. Material is fed over the moving decks . The oscillations stop the small aperture holes from blinding up and allow wet materials to be effectively screened at a constant feed rate. Other screening mechanisms will very quickly blind if a batch of wet material is fed over the screen. The screen is also self-cleaning and will free itself of dirt by being left to run empty for a little while. Finally, the screen offers a great deal of versatility in that the neoprene decks can be changed very quickly and the size cut can be easily adjusted for seasonal and waste type variations .

The -10mm material that is cut from the material stream is a mainly inert product which includes items such as shredded paper and fine plastic film along with dried organic material . This material has a high calorific value .

It is noted that the invention is not confined to the above-described IFE Variomat Screen as the sole option for the primary screen and the IFE Trisomat screen as the sole option for the fines screen.

5. Further Processing of 10-60mm Fraction and the +60mm Fraction

The 10-60mm fraction and the +60mm fraction are placed onto separate conveyor systems via vibratory feeders 13 and transported past a series of "contaminant" assessment and sorting stations and processed as described below to produce the substantially plastics material product (which is a form of a solid residual fuel (SRF) ) for the larger fraction and a refuse-derived fuel (RDF) for the smaller size fraction. As noted above, the term "contaminant" is understood in the context of the end-use products .

6. Optical Sorters — item 15 in Figure 1

The first further processing station for each of the

10-60mm fraction and the +60mm fraction is an optical sorter 15 which optically identifies and removes fibres and target plastics materials such as PVC . These materials are another refuse-derived product (RFD) and are bagged and sold as RDF. One option for an optical sorter for the detection and removal of plastics including PVC is a Red Wave Optical Sorter. Advantages of the system are the overall width of the unit. For this embodiment, both the larger (+60mm) and smaller (10-60mm) fractions will be fed in parallel optical sorting machines.

7. Eddy Current Sorter — item 17 in Figure 1

The 10-60 mm fraction and the +60 mm fraction are then each transported past an eddy current sorter 17 that identifies and removes non-ferrous metals, such as aluminium. The aluminium is another valuable product. The eddy currents are designed specifically for the size cut, with the smaller fraction passing over an 18 pole rotor and the larger fraction passing over a 10 pole rotor. Each rotor is designed to achieve maximum product removal from the waste.

8. Magnetic Sorter - item 19 in Figure 1

The +60 mm fraction is then transported past a magnetic sorter 19 as a final safety measure to remove any magnetic material, such as steel, from the larger size fraction.

Once the waste feed materials have been processed through the first unit, the main end-use product, namely the substantially plastics material product, is fed directly into the second unit and processed in the second unit to produce a composite product.

9. Secondary screen — item 21 in Figure 1

The +60 mm fraction is then transported past a secondary screen 21 and separated into a smaller size fraction and a larger size fraction. Essentially, the screen 21

separates any remaining non-plastics material from the +60 mm fraction. The smaller fraction is another refuse- derived product (RFD) and is bagged and sold as RDF. The larger fraction is substantially pure plastics material and forms a solid residual fuel (SRF) . As noted above, the product can be used in a wide range of end-use applications. One application is described below in relation to the second unit.

Unit (the "second unit") for producing polymer charge carbon

The second unit for producing a composite product as described in the above-mentioned International application PCT/AU2011/000960 (WO 2012/019216) in the name of the OneSteel NSW Pty Limited that is suitable for use as a polymer charge carbon for an electric arc steel making furnace has been designed to be independent of the first unit of the plant. This independence of the first and second units allows the plant to be able to produce two products at the same time. There will be situations in which the product of the first unit is transferred directly to the second unit and other situations where this is not the case. In some situations, the first and second units may be in different locations altogether . In this situation, the product of the first unit may be transported to the second unit.

The production of the composite product is achieved in the following steps illustrated in Figure 2, namely: 1. Granulation of the substantially plastic feed material from the first unit.

2. Mixing the substantially plastic feed material and carbon-bearing feed material, such as coal or coke, to a prescribed recipe. 3. Extruding the mixture using heat to at least partially melt the plastic feed material to act as a binding agent.

Step 1 Granulation — item 23 in Figure 2

The substantially plastics material from the first unit is granulated to —2mm. Typically, the granulator 23 is selected to be a high speed granulator . The

granulated plastics material is discharged via a pneumatic conveyor to silo hoppers . It is noted that the invention is not confined to the —2mm granule size and the granules may be any suitable size. It is also noted that the granulation step may not be required for other end-use applications of the substantially plastics material from the first unit.

Storage of Polymers — item 27 in Figure 2

The granulated plastics material is discharged from the granulator 23 and transported via a pneumatic conveyor to silo hoppers 27. Due to the very light density of the product and the ability of the product to litter, the process system is sealed post granulation.

Storage of Coke — item 27 in Figure 2

A coke feed which is suitable in terms of structural properties and calorific value and has a required particle size distribution is transferred via a drag link conveyor 33 to a storage hopper 27 and retained in the hopper.

Product Mixing — item 35 of Figure 2

The mixing of the plastics material and the coke is to a very precise recipe. The plastics material and the coke are separately transferred from the respective hoppers 27 to respective weigh stations 29 and the predetermined weights of these feed materials in

accordance with the recipe are transferred to a mixing plant 35. The mixing plant 35 for this embodiment is designed to receive a maximum of lm³ of feed materials and to mix them together to form a homogeneous mixture. The mixing plant may be any suitable capacity.

Extrusion — item 37 in Figure 2

Once mixed into a homogeneous form, the feed

composite product mixture is fed to two separate extruders 37 (or any suitable number of extruders) and heated and extruded into solid rods of fuel. Each extruder 37 comprises an elongate cylindrical chamber that is heated along the length of the chamber and has an inlet end for receiving the composite product mixture and an outlet end that has a series of outlet openings that are shaped as required to form the extrusion profile. Each extruder also includes a motor-driven auger in the chamber to move the composite product mixture along the length of the chamber from the inlet to the outlet.

The applicant has made a number of findings in relation to the extrusion requirements, as follows:

1. When the plastic material and coke are heated they become plastic (like clay) . However, temperature control is very important, too much heat and the product starts to degrade and too little heat and the product is too stiff and will not flow.

2. In view of item 1 , it was necessary to design the auger displacement against a thermal calculation where the product moves at a speed where it has time to become plastic enough to flow, but not too plastic as to damage the product. 3. The auger speed affects the torque output of the motor and the force the motor exerts needs to meet the extruding needs of the product, which are: speed of screw- (throughput) and heat input into the product. The balance and control of these variables are critical to the manufacture of useable carbon charge .

4. The applicant has designed a control program and set out gear box ratios to balance throughput against heat absorbed into the product. As different plastics have different melting points, the optical sorters 15 are set up to record the composition of the plastics material in the waste plastic product in the first unit and to calculate the Standard Heat Capacity of the product. This information automatically sets auger speed and current settings - (torque output) of the motor.

5. The applicant has refined the relationship between auger speed, current draw, burden depth of the auger to ensure production of a high quality extruded rod.

6. Finally, the applicant has designed a cutter that cuts the rods automatically when the rods get to a correct length. Length is calculated on volumetric auger

displacement and can be set to the requirements of the furnace. Control of the cutter speed again is measured through a PLC and the inputs the PLC records (speed of motor, current draw and estimated SHC of product) .

The above-described first unit is an effective and efficient unit for forming a substantially plastics material product that has a number of possible end-use applications .

The above-described second unit is an effective and efficient unit for manufacturing a composite product that is suitable for use as a polymer charge carbon for an electric arc steel making furnace. Many modifications may be made to the embodiments of the present invention described above without departing from the spirit and scope of the invention.

By way of example, the embodiment of the present invention described in relation to the Figures is not confined to the specific equipment described above. The present invention is also not limited to the particular arrangement of unit operations and additional unit operations may be used as required for a particular waste feed material. In addition, the present invention is not confined to the use of the particular waste feed materials

By way of further example, the present invention is not confined to composite products that are suitable for use in high temperature processes . By way of example , the composite products of the present invention are suitable for use as building materials or as protective materials for building and wear resistant materials (e.g. for wear resistance or corrosion resistance) , such as alternatives to timber products and steel products .

Claims

1. A method of manufacturing a product that

substantially comprises plastics material from a co- mingled waste feed material that includes the following steps :

(a) shredding the waste feed material;

(b) separating the shredded plastics waste feed material and the other shredded waste feed material based on size into a first process stream that is predominantly waste plastics material and at least a second process stream that is a mixture of waste plastics material and other waste feed materials such as paper; and

2. The method defined in claim 1 wherein the further processing steps for the first process stream include an optical sorting to remove fibrous material and selected plastics materials, such as PVC, that are not required for the substantially plastics material product.

3. The method defined in claim 1 or claim 2 wherein the further processing steps for the first process stream include eddy current sorting to remove non-ferrous metals .

4. The method defined in any one of the preceding claims wherein the further processing steps for the first process stream include magnetic sorting to remove magnetic material .

5. The method defined in any one of the preceding claims includes further processing the second process stream, which is a mixture of waste plastics material and other waste feed materials such as paper, and producing an end- use product in the form of refuse-derived waste material that can be used as an energy source in cement kilns and other applications .

6. The method defined in claim 5 wherein the further processing steps for the second process stream include optical sorting to remove fibrous material and selected plastics materials that are not required for the

substantially plastics material product.

7. The method defined in claim 5 or claim 6 wherein the further processing steps for the second process stream include eddy current sorting to remove non-ferrous metals, such as aluminium.

8. The method defined in any one of the preceding claims wherein the co-mingled waste feed material is obtained from a commercial materials recovery facility ("MRF") that receives and processes waste materials (for example by separating the materials into different categories) , and prepares recyclable materials for end-use manufacturers .

9. The method defined in any one of the preceding claims wherein the co-mingled waste feed material includes waste plastics material in the form of films or bottles or other containers made from plastics materials .

10. The method defined in any one of the preceding claims wherein the co-mingled waste feed material is obtained from a paper mill .

11. The method defined in claim 10 wherein the paper mill waste includes paper mill rejects, such as hydro-puled paper and plastics materials (associated with the paper) that cannot be used for new paper production.

12. The method defined in any one of the preceding claims produces other end-use products in addition to the substantially plastics material .

13. The method defined in claim 12 wherein the other products include any one or more of metal and refuse- derived fuel .

14. The method defined in any one of the preceding claims wherein the substantially plastics material product comprises at least 80 wt.% plastics material.

15. The method defined in any one of the preceding claims wherein the substantially plastics material product comprises at least 95 wt.% plastics material.

16. A substantially plastics material product

manufactured by the method defined in any one of the preceding claims .

17. A plant for manufacturing a product that

substantially comprises plastics material from a co- mingled waste feed material, with the plant comprising:

(a) a shredder for shredding the waste feed

material ;

18. The plant defined in claim 17 includes any one or more than one of an optical sorter, an eddy current sorter and a magnetic sorter to remove "contaminants" from the second process stream to produce the substantially plastics material product.

19. A method of producing a composite product for use in a metallurgical furnace that comprises mixing and heating the substantially plastics material produced by the method defined in any one of claims 1 to 15 and another carbon- bearing material at the same time or sequentially and thereafter forming the heated mixture into a final product shape of the composite product, with the heating step melting at least a part of the plastics material to facilitate forming the product.

20. The method defined in claim 19 wherein the forming step is an extrusions step .

21. A composite product manufactured by the method defined in claim 19 or claim 20.