Trends in Plastics and

Aluminium Recycling

Salman Zafar

INTRODUCTION

Like all other modern urban centers, the Middle East also faces challenges in environmental

protection due to tremendous tonnage of waste produced in different forms. Bahrain, Saudi

Arabia, UAE, Qatar and Kuwait rank in the top-ten worldwide in terms of per capita solid waste

generation. The gross urban waste generation quantity from Middle East countries is estimated

at more than 120 million tons annually. The burgeoning population, growing consumption, and

an increasing trend towards a “disposable” culture, is causing nightmares to municipal

authorities across the region and beyond.

The demand for plastics, paper, aluminium, rubber etc continues to grow across the Middle

East region at a rapid pace which may lead to severe environmental problem in the near future.

Recycling is gaining prominence as a vital waste management option worldwide, and the

Middle East has been witnessing significant activity in this segment in recent years. Energy

conservation coupled with climate change mitigation is the main advantage associated with

waste recycling. Recycling also facilitates a transition from the current linear model to a cyclic

way of living, which is essential for countering environmental degradation and fostering

sustainable development.

INCREASING USE OF PLASTIC AND ALUMINIUM

Plastic consumption has grown at a tremendous rate over the past two decades as plastics now

play an important role in all aspects of modern lifestyle. Plastics are used in the manufacture of

numerous products such as protective packaging, lightweight and safety components in cars,

mobile phones, insulation materials in buildings, domestic appliances, furniture items, medical

devices etc. Because plastic does not decompose biologically, the amount of plastic waste in

our surroundings is steadily increasing. More than 90% of the articles found on the sea beaches

contain plastic. Plastic waste is often the most objectionable kind of litter and will be visible for

months in landfill sites without degrading.

Aluminium is used extensively in aircraft, building construction, electrical transmission and

consumer durables such as fridges, cooking utensils and air conditioners as well as in food

Bahrain, Saudi Arabia, UAE, Qatar and Kuwait rank in the top-10 worldwide in terms

of per capita solid waste generation.

Disposal of plastic waste has emerged as an important environmental challenge and

its recycling is facing roadblocks due to their non-degradable nature.

processing equipment and cans. Infact, the use of aluminum exceeds that of any other metal

except iron.

Aluminium exposed to fires at dumps can be a serious environmental problem in the form of

poisonous gases and mosquito breeding. Recycled aluminium can be utilized for almost all

applications, and can preserve raw materials and reduce toxic emissions, apart from significant

energy conservation.

RECYCLING AND REUSE OF PLASTICS

Recycling and reuse of plastics is gaining importance as a sustainable method for plastic waste

disposal. Unfortunately, plastic is much more difficult to recycle than materials like glass,

aluminum or paper. A common problem with recycling plastics is that plastics are often made

up of more than one kind of polymer or there may be some sort of fibre added to the plastic (a

composite). Plastic polymers require greater processing to be recycled as each type melts at

different temperatures and has different properties, so careful separation is necessary.

Moreover, most plastics are not highly compatible with one another. Apart from familiar

applications like recycling bottles and industrial packaging film, there are also new

developments e.g. the Recovinyl Initiative of the PVC industry (covering pipes, window frames,

roofing membranes and flooring).

Polyethlene terephthalate (PET) and high density polyethylene (HDPE) bottles have proven to

have high recyclability and are taken by most curbside and drop-off recycling programs. The

growth of bottle recycling has been facilitated by the development of processing technologies

Commonly Recyclable Plastics

� High Density Polyethylene (HDPE) used in piping, automotive fuel tanks, bottles, toys,

� Low Density Polyethylene (LDPE) used in plastic bags, cling film, flexible containers;

� Polyethylene Terephthalate (PET) used in bottles, carpets and food packaging;

� Polypropylene (PP) used in food containers, battery cases, bottle crates, automotive

parts and fibres;

� Polystyrene (PS) used in dairy product containers, tape cassettes, cups and plates;

� Polyvinyl Chloride (PVC) used in window frames, flooring, bottles, packaging film, cable

insulation, credit cards and medical products.

Aluminium is the second most widely used metal whereas the aluminum can is the

most recycled consumer product in the world.

that increase product purities and reduce operational costs. Recycled PET and HDPE have many

uses and well-established markets.

In contrast, recycling of polyvinyl chloride (PVC) bottles and other materials is limited. A major

problem in the recycling of PVC is the high chlorine content in raw PVC (around 56 percent of

the polymer's weight) and the high levels of hazardous additives added to the polymer to

achieve the desired material quality. As a result, PVC requires separation from other plastics

before mechanical recycling.

RECYCLED PET

Recycled PET (RPET) is based on collected bottle scrap in the form of soft drinks and water

bottles. The empty bottles are collected, cleaned, and ground into flakes. The flakes are then

melted to form part of the finished sheet, which is used for the production of food packaging.

Recycled PET provides the foundation for a wide range of new products. Since its properties as

a recyclate are similar to those displayed by the new product, it can be used in many different

areas. On the one hand the textile industry uses recycled PET for polyester fibers; on the other

hand the automotive industry uses PET for plastic components. The packaging industry

produces strapping, sheets and bottles from recycled PET. RPET undergoes a stringent cleaning

process which makes it absolutely safe even in direct contact with food. Sometimes RPET is put

Five Steps in Plastics Recycling

Step 1: Collection

This is done through roadside collections, special recycling bins and directly from

industries that use a lot of plastic.

Step 2: Sorting

At this stage nails and stones are removed, and the plastic is sorted into three types:

PET, HDPE and 'other'.

Step 3: Chipping

The sorted plastic is cut into small pieces ready to be melted down.

Step 4: Washing

This stage removes contaminants such as paper labels, dirt and remnants of the

product originally contained in the plastic.

Step 5: Pelletization

The plastic is then melted down and extruded into small pellets ready for reuse.

PET and HDPE bottles have high recyclability and are integral to mostt curbside and drop-off

recycling programs.

into a separate layer to impart special properties to the outer layer, for example good heat

sealing.

POLYETHYLENE AND POLYPROPYLENE RECYCLATES

Used containers like bottles and canisters made of HDPE or polypropylene are turned into high

quality materials in modern recycling plants. This recycled material can be turned into first-class

products that are demanded all over the world. There has been good deal of commercial

research and development on recycling HDPE milk containers into re-compounded pellets

suitable for use in food grade applications. HDPE bottles are flaked and washed, before passing

through automatic flake sorting equipment. This removes any remaining contamination (e.g.

particles of metals, wood, glass, etc) and any coloured HDPE which may have entered the

recycling process. The final step is extrusion of the flake, at a high temperature and under

vacuum, to produce a re-compounded pellet. Processors such as injection moulding

manufacturers, blow-moulders, or film manufacturers have a long term demand for these

recycled granulates.

POLYURETHANE RECYCLING

Polyurethane (PUR) accounts for about 5% of all plastic waste. The high costs of separating the

PUR wastes from other components of discarded automobiles have been barriers to recovery

and re-use of PUR in motor vehicles. However, automakers around the world are beginning to

design vehicles for easy and economical removal of PUR seat cushions for recycling. Reaction

injection molded parts in autos, found in bumper skins and side protection panels, have been

commercially recycled for various applications, both automotive and non-automotive.

ALUMINIUM RECYCLING

The demand for aluminium products is growing steadily because of their positive contribution

to modern living. Aluminium finds extensive use in air, road and sea transport; food and

medicine; packaging; construction; electronics and electrical power transmission. Aluminum

has a high market value and continues to provide an economic incentive to recycle it. The

excellent recyclability of aluminium, together with its high scrap value and the low energy

needs during recycling make aluminium lightweight solutions highly desirable.

The contribution of the recycled metal to the global output of aluminium products has

increased from 17 percent in 1960 to 34 percent today, and expected to rise to almost 40

percent by 2020. Global recycling rates are high, with approximately 90 per cent of the metal

Recycled PET is widely used in textile, automotive and packaging industries.

used for transport and construction applications recovered, and over 60 per cent of used

beverage cans are collected.

Aluminium does not degrade during the recycling process, since its atomic structure is not

altered during melting. Aluminium recycling is both economically and environmentally

effective, as it requires a lot less energy to recycle than it does to mine, extract and smelt

aluminium ore. Recycled aluminium requires only 5% of the energy used to make primary

aluminium, and can have the same properties as the parent metal. However, in the course of

multiple recycling, more and more alloying elements are introduced into the metal cycle. This

effect is put to good use in the production of casting alloys, which generally need these

elements to attain the desired alloy properties.

The industry has a long tradition of collecting and recycling used aluminium products. Over the

years, USA and European countries have developed robust separate collection systems for

aluminium packaging with a good degree of success. Recycling aluminium reduces the need for

raw materials and reduces the use of valuable energy resources. Recycled aluminium is made

into aircraft, automobiles, bicycles, boats, computers, cookware, gutters, siding, wire and cans.

ALUMINIUM CAN RECYCLING

The aluminum can is the most recycled consumer product in the world. Each year, the

aluminum industry pays out more than $800 million for empty aluminum cans. Recycling

aluminium cans is a closed-loop process since used beverage cans that are recycled are

primarily used to make beverage cans. Recycled aluminium cans are used again for the

production of new cans or for the production of other valuable aluminium products such as

engine blocks, building facades or bicycles. The latter also applies to other aluminium rigid and

semi-rigid packaging such as aerosol cans, food cans, menu trays, cups, tubes, capsules and

closures. In Europe about 50% of all semi-fabricated aluminium used for the production of new

beverage cans and other aluminium packaging products comes from recycled aluminium.

The life cycle of an aluminium product is not the traditional "cradle-to-grave" sequence,

but rather a renewable "cradle-to-cradle".

Recycled aluminium requires only 5% of the energy used to make primary aluminium.

Aluminium can be recycled endlessly with loss of material properties.

ALUMINIUM PACKAGING

Aluminium packaging fits every desired recycling and processing route. Aluminium packaging

needs to be separated from other packing material when intended for material recycling. A

growing number of sorting facilities are equipped with eddy current separators which offer a

comprehensive means of sorting the aluminium fraction.

Multi-material packaging systems may consist of plastics, tinplate, beverage cartons and paper

packaging, apart from aluminium packaging, e.g. beverage cartons. A variety of systems have

been developed to extract aluminium from complex packaging systems, such as repulping,

mechanical separation and pyrolysis. In pyrolysis, the non-metallic components are removed

from the aluminium by evaporation. A newer technology is the thermal plasma process where

the three components – aluminium, plastic and paper – are separated into distinct fractions.

RECYCLED ALUMINIUM FROM MUNICIPAL SOLID WASTE

Aluminium can also be extracted from the bottom ashes of municipal solid waste incinerators

as aluminium nodules. In many European countries, municipal solid waste is entirely or partly

incinerated; in this case the contained thin gauge aluminium foil is oxidized and delivers energy

while thicker gauges can be extracted from the bottom ash. Eddy current machines and

detection-ejection systems are implemented to extract aluminium from mixed materials flows

as well as from incinerator bottom ashes where it is highly diluted.

Step-by-Step Guide to Aluminium Can Recycling

Step 1: Aluminium cans are collected from recycling centers, community drop-off sites,

curbside pick-up spots etc.

Step 2: Compressed into highly dense briquettes or bales at scrap processing facilities and

shipped to aluminum companies for melting.

Step 3: Condensed cans are shredded, crushed and stripped of their inside and outside

dyes. The potato chip-sized pieces are loaded into melting furnaces, where the recycled

metal is blended with brand new aluminum.

Step 4: Molten aluminum is converted into ingots which are fed into rolling mills that

reduce the thickness to about 1/100 of an inch.

Step 5: This metal is then coiled and shipped to can manufacturers. The cans are then

delivered to beverage companies for filling.

Step 6: The new cans, filled with your favorite beverages, are then returned to store shelves

in as little as 60 days … and the recycling process begins again!