E-Waste Recycling–An Introduction
E-waste comprises of wastes generated from used electronic devices and household appliances which are not fit for their original intended use and are destined for recovery, recycling or disposal. Such wastes encompasses wide range of electrical and electronic devices such as computers, hand held cellular phones, personal stereos, including large household appliances such as refrigerators, air conditioners etc. E-wastes contain over 1000 different substances many of which are toxic and potentially hazardous to the environment and human health, if not handled in an environmentally sound manner.
E-waste according to the E-waste (Management and Handling) Rules, 2010, means waste electrical and electronic equipment, whole or in part but not limited to equipment listed in Schedule 1 and scraps or rejects from their manufacturing and repair process, which is intended to be discarded.
The perception of e-waste is often restricted to a narrower sense, comprising mainly of end-of-life information - telecommunication equipment and consumer electronics. However, technically, electronic waste is only a subset of WEEE (Waste Electrical and Electronic Equipment).
Composition of E-Waste
Composition of e-waste is very diverse and differs in products across different categories. It contains more than 1000 different substances, which fall under “hazardous” and “non-hazardous” categories. Broadly, it consists of ferrous and non-ferrous metals, plastics, glass, wood plywood, printed circuit boards, concrete and ceramics, rubber and other items. Iron and steel constitutes about 50% of the e-waste followed by plastics (21%), non-ferrous metals (13%) and other constituents. Non-ferrous metals consist of metals like copper, aluminium and precious metals ex. silver, gold, platinum, palladium etc. The presence of elements like lead, mercury, arsenic, cadmium, selenium, hexavalent chromium and flame-retardants beyond threshold quantities in e-waste classifies them as hazardous waste.
Components of E-Waste
E-waste has been categorized into three main categories, viz. Large Household Appliances, IT, Telecom and Consumer Equipment. Refrigerator and Washing Machine represent large household appliances, Personal Computer, Monitor and Laptop represent IT and Telecom, while Television represents Consumer Equipment. Each of these E-waste items has been classified with respect to twenty-six common components, which could be found in them. These components form the “Building Blocks” of each item and therefore they are readily “identifiable” and “removable”. These components are metal, motor/ compressor, cooling, plastic, insulation, glass, LCD, rubber, wiring/electrical, concrete, transformer, magnetron, textile, circuit board, fluorescent lamp, incandescent lamp, heating element, thermostat, BFR-containing plastic, batteries, CFC/HCFC/HFC/HC, external electric cables, refractory ceramic fibers, radio active substances and electrolyte capacitors (over L/D 25 mm).
SWOT Analysis
SWOT analysis is a structured planning method used to evaluate the strengths, weaknesses, opportunities and threats involved in E-waste Management. It involves specifying the objective of the business venture and identifying the internal and external factors that are favorable and unfavorable to achieve that objective. The SWOT analysis on e-waste and its management has been developed to provide the full awareness of the situation in the region, in order to guide on policy and guideline development, sustainable decision making and problem solving regarding e-waste management in the region.
Integrated Product Policy
Integrated product policy (IPP) is a public policy initiative which has been on the EU agenda since roughly the late 1990s and is concerned with the reduction of environmental impact associated with products and services. The purpose of the EC initiative was to harmonise varying environmental product policy strategies that were developing within the Community to minimise the environmental impact of their products at varying stages of the product life cycle: for example, take-back schemes, product labelling, taxes or other economic initiatives.
Sustainable Development
One of the objectives of the sixth EAP which implements the EU waste strategy was to decouple economic growth from environmental degradation and to bring about a situation where resources were used more efficiently and waste management was improved so that more sustainable patterns in production and consumption were established. The strategy is based on seven key challenges, and most relevant to this discussion are:
• to limit climate change;
• to limit the adverse effects of transport;
• to promote more sustainable modes of production and consumption and breaking the link between economic growth and environmental degradation;
• more responsible management of natural resources.
Overview of WEEE/E-Waste Management
WEEE/E-waste is a complex mixture of hazardous and non-hazardous waste requiring specialized segregation, collection, transport, treatment and disposal. Against this backdrop, this chapter overviews the collection and transport systems as key components driving the overall efficiency of WEEE/E-waste management systems. Since collection and transport are involved in each step of the material flow during WEEE/E-waste trade, each has been summarized below, followed by a description of the components of WEEE/E-waste management and elements of WEEE/E-waste collection and transport systems. These elements form the basis of WEEE/E-waste take-back systems. The stakeholders involved are also noted below, followed by guidance notes.
Mechanism of WEEE/E-waste Trade
Three elements encapsulate the mechanism of WEEE/E-waste trade, specifically:
1. Material flow
2. Life cycle
3. Geographical boundary
The following sections provide the basis for understanding the role of WEEE/E-waste collection and transport within waste management, from WEEE/E-waste generation through its transformation into new materials.
Components of WEEE/E-waste Management
Phases II, III and IV of the material flow model define the three major components of WEEE/E-waste management systems, namely:
1. WEEE/E-waste collection, sorting and transport systems
2. WEEE/E-waste treatment system
3. WEEE/E-waste disposal system
WEEE/E-waste collection, sorting and transport systems are the key link between WEEE/E-waste generation and treatment, reuse and disposal and these systems’ operational efficiency is dependent on their management systems and the stakeholders responsible for their management. Their respective management systems consist of producer and retailer take-back.
Barriers to Recycling of WEEE
One of the main barriers to recycling of WEEE by manufacturers is the distribution of WEEE in relation to the location of the manufacturing plant. Many WEEE manufacturers are based a significant distance from their markets and also from the resulting waste. This makes it difficult and expensive for them to operate take-back facilities specifically for their appliances.
Retailers and distributors are in the best position to collect WEEE, as old appliances can be collected when delivering the new ones, or people can take small appliances to their local store when buying/collecting a new appliance. The barriers to such schemes are that the retailers would need to carry the cost for collection points and provide storage facilities, which, apart from space constraints, would also have security and health and safety implications.
WEEE Health and Safety Implications
Electrical and electronic products contain a wide range of materials and some of these are known to present potential health and safety issues for workers involved in their treatment at end of life.
In recognition of the growing concerns around the use of brominated flame retardants, there have been moves by the industry to develop a coordinated approach to best practice. A good example of this approach is given by the Voluntary Emissions Control Action Programme (VECAP), which was established by the brominated-flame-retardant industry. VECAP was set up to manage, monitor and minimise industrial emissions of brominated flame retardants into the environment through partnership with Small and Medium-sized Enterprises (SMEs).
Hazardous Materials in E-Waste
Electrical and electronic equipment contain different hazardous materials which are harmful to human health and the environment if not disposed of carefully. While some naturally occurring substances are harmless in nature, their use in the manufacture of electronic equipment often results in compounds which are hazardous (e.g. chromium becomes chromium VI). The following list gives a selection of the mostly found toxic substances in e-waste.
Valuable Materials in E-Waste
Electrical and electronic equipment contain various fractions of valuable materials. Most of the valuable substances are found in printed circuit boards, which occur in relevant quantities mainly in the categories Office, Information and Communication Equipment as well as Entertainment and Consumer Electronics. Besides well known precious metals such as gold, silver, platinum and palladium also scarce materials like indium and gallium start to play an important role, due to their application in new technologies (e.g flat screens, photovoltaics).
POSSIBLE HAZARDOUS SUBSTANCES PRESENT IN E-WASTE
Component Possible Hazardous Content
• Metal
• Motor\Compressor
• Cooling ODS
• Plastic Phthalate plasticize, BFR
• Insulation ODS in foam, asbestos, refractory ceramic fiber Glass
• CRT Lead, Antimony, Mercury, Phosphors
• LCD Mercury
• Rubber Phthalate plasticizer, BFR
• Wiring / Electrical Phthalate plasticizer, Lead, BFR
Glycol, Other Unknown Substances
The substances within the above mentioned components, which cause most concern, are the heavy metals such as lead, mercury, cadmium and chromium, halogcnatcd substances (e.g. CFCs), polychlorinated biphenyls, plastics and circuit boards that contain brominated flame retardants (BFRs). BFR can give rise to dioxins and furans during incineration. Other materials and substances that can be present are arsenic, asbestos, nickel and copper. These substances may act as a catalyst to increase the formation of dioxins during incineration. The description about some of these substances where uncertainty exists regarding their “level of concern” based on literature review are given below.
Components Containing Plasticisers/Stabilizers
The concerns here include the use of phthalate plasticizers and lead stabilizers in plastics and rubbers. For example, dibutyl phthalate and diethylhexyl phthalate are considered “Toxic for Reproduction” at concentrations >=0.5%.
Circuit Boards
While most boards are typically 70% non metallic, they also contain about 16% copper, 4% solder and 2% nickel along with iron, silver, gold, palladium and tantalum. Approximately 90% of the intrinsic value of most scarp boards is in the gold and palladium content. Consequently, traditional reprocessing of circuit boards has concentrated on the recovery of metals values. Some of the components found in circuit boards are described below.
Mercury
It is estimated that 22% of the yearly world consumption of mercury is used in electrical and electronic equipment (ex. in fluorescent lamps). Its use in EEE has declined significantly in recent years. It has been used in thermostats, (position) sensors, relays and switches (ex. on printed circuit boards and in measuring equipment), batteries and discharge lamps.
Furthermore, it is used in medical equipment, data transmission, telecommunications, and mobile phones. The estimated concentration level of mercury in computers is 0.002%.
Beryllium
Copper beryllium alloys are used in electronic connectors where a capability for repeated connection and disconnection is desired, and thus where solder is not used to make a permanent joint. Such connectors are often gold plated, so that copper oxide is not created on their surfaces, and does not form a non-electrically conductive barrier between the two connectors. A second use of beryllium in the electronics industry is as beryllium oxide, or beryllia. Beryllia transmits heat very efficiently, and is used in heat sinks.
Capacitors Containing Poly Chlorinated Biphenyls (PCBs)
PCBs were extensively used in electrical equipment such as capacitors and transformers. Their use in open applications was widely banned in 1972 in Europe and they have not been used in the manufacture of new equipment since 1986. Capacitors containing PCBs fall into two categories, according to size. Small capacitors were used in fluorescent/ other discharge lamps and also with fractional horsepower motors used in domestic and light-industrial electrical equipment. Large capacitors were used for power factor correction and similar duties.
E-Waste Management System Specifications
This chapter describes the E-waste management system specifications of the technology proposed and its financial viability. In this chapter, at first, specifications of E-waste collection and transportation system has been described followed by specification of 1st and 2nd level of E-waste treatment. These specifications are based on the technical specifications, which are used globally and the cost estimates from international plant and equipment suppliers.
Tentative Specifications for E-Waste Collection System
The volume of E-waste item to be collected and transported till 2020 based on E-waste inventory estimates in Phnom Penh is given in table 1. This is based on 50% availability of E-waste for recycling.
Depending upon the type of E-waste, different types of bins/cages will be used as shown in figure 1. The collected E-waste in container will be lifted manually, through fork lifts, placed into small trucks/container carriers and transported from the collection facility to E-waste treatment facility.
Tentative Specifications for E-waste Treatment System
E-waste treatment facility will consist of 1st and 2nd level E-waste treatment. After 1st and 2nd level E-waste treatment, E-waste fractions will be sold/ exported to 3rd level recyclers for precious metals recovery. The installed capacity of the 1st and 2nd level plant has been conceptualized to be about 9 tons per day during 2009 to 32 tons per day during 2019 considering 50% collection efficiency.
Common Specifications for Utilities at Collection Centers and Processing Facilities
E-waste storage areas/ Hazardous waste storage areas/ Product storage areas should follow following basic design principles.
1. Sites for storage (including temporary storage) of E-waste prior to their treatment should have impermeable surface for appropriate areas with the provision of spillage collection facilities and where appropriate, decanters and cleanser-degreasers.
2. Sites for storage (including temporary storage) of E-waste prior to their treatment should have weatherproof covering for appropriate areas.
3. Some spare parts (e.g. motors and compressors) will contain oil and/or other fluids. Such part must be appropriately segregated, end stored in containers that are secured such that oil and other fluids cannot escape from them These containers must be stored on an area with an area with an Impermeable surface and a sealed drainage system.
4. Waste Oil should be either reused or incinerated in common hazardous waste incineration facilities.
Recycling of E-Waste
Individual Processes
One of the most common pieces of equipment used for initial crushing and shredding is a hammer mill. Hammer mills accomplish size reduction by impacting a slow moving target with a rapidly moving hammer. The target has little or no momentum (low kinetic energy), whereas the hammer tip is travelling at rates of typically up to 7000 m min–1 and higher (high kinetic energy).
Material disintegration may also be effected by the use of metal crushers which have low specific energy consumption and offer high operational immunity to the presence of solid pieces and may be also used as a pre-stage prior to shredding.
Size Classification
Screeners are sifting units that are rotated as powder is fed into their interior. The finer particles fall through the sieve opening and oversized particles are ejected off the end. Rotary sifters or drum screeners are often used for de-agglomerating or de-lumping type operations. Screeners are available in three main types: drum sifter, rectangular deck and round deck.
Magnetic Separation
Magnetic separators such as low-intensity drum types are widely used for the recovery of ferromagnetic materials from non-ferrous metals and other nonmagnetic materials. There have been many advances in the design and operation of high-intensity magnetic separators due mainly to the introduction of rare-earth alloy permanent magnets with the capability of providing high field strengths and gradients. For WEEE, magnetic separation systems utilise ferrite, rare-earth or electromagnets, with high-intensity electromagnet systems being used extensively and which are particularly suited to materials fed to the underside of drum magnets; see Figure 3.
Density Separation
Several different methods may be deployed to separate heavier fractions from lighter ones, the basis being the difference in density to enable such. Gravity concentration separates materials of different specific gravity by their relative movement in response to the action of gravity and one or more other forces, such as the resistance to motion offered by water or air. The motion of a particle in a fluid is dependent not only upon the particle’s density, but also on its size and shape; large particles are affected more than smaller ones. In practice, close size control of feeds to gravity separation equipment is required in order to minimise size effects and render the relative motion of the particle gravity dependent.
Electrostatic Separation
The rotor type electrostatic separator, using corona charging, may be utilised to separate raw materials into conductive and non-conductive fractions. The extreme difference in the electrical conductivity or specific electrical resistance between metals and non-metals affords an excellent pre-condition for the successful implementation of a corona electrostatic separation in recycling of waste. Electrostatic separation has been mainly used for the recovery of copper or aluminium from chopped electric wires and cables and, more specifically, for the recovery of copper and precious metals from printed circuit board scrap; see Figure 4.
Metals
As noted previously, metals constitute the most valuable and easiest-to-recycle materials. A recent study concluded that ‘There appear to be no major difficulties concerning the recovery and recycling of metals from WEEE. Metals also constitute the largest weight of materials in WEEE, around 47% overall for small mixed WEEE. Current recycling processes are capable of recovering <95% of the in-feed metals.
Plastics
On average plastics constitute approximately 20% of collected WEEE. A number of distinct materials streams are produced from WEEE recycling. Some from segregated appliance types are fairly homogeneous and can be recycled. The plastics stream from mixed WEEE processing contains a large number of different polymers that are difficult to separate - according to a recent study ‘Data from literature seems to confirm that at present plastic output streams from WEEE recycling operations are mostly not recovered, but are landfilled together with other residue streams’.
Automated Disassembly
Disassembly is seen by many as an essential element, even for relatively well-defined input streams, if value is to be extracted. The high labour burden of this stage is driving research into automated techniques. In automating the process the main issues to be addressed are: imaging, recognition and robotics. Demands on these are reduced by attention to upstream issues.
Separation
Efficient separation is a prime requirement for effective WEEE recycling, and can reduce reliance on dismantling. A range of sorting systems is available for separating materials in general scrap, after comminution, according to properties such as weight, size, shape, density and electrical and magnetic characteristics. Some research groups are carrying out characterisation studies in order to determine costs, and to optimise the level of particle size from the comminution process. Although new techniques are being developed, much of the novelty in WEEE separation is expected to emerge from adapting existing techniques, and from novel combinations. Initially this is usually for specific input streams, but more sophisticated routes are being developed to handle a wider variety of input items.
Thermal Treatments
Thermal treatments have the advantages of greatly reducing bulk and avoiding liquid effluent for the primary recycler. Pyrometallurgical routes are suitable for the recovery of metal values. There are established operators in place who incinerate the non-metallic content to produce ash, which can be used as feedstock in the pyrometallurgical processes. The final products tend to be partly refined metal ingots, such as ferrous, aluminium, mixed Pb/Sn and, most importantly, a copper-rich precious metals mix, which require further treatment by specialist refiners. Continuing research into these methods could improve the quality of metals recovered.
Hydrometallurgical Extraction
Hydrometallurgy offers the possibility to achieve more selective metal recovery and to reach higher recycling percentage targets. Indeed these methods are often used by specialist refiners of precious metals following initial pyrometallurgical extraction. However, future research must address the need to avoid the use of hazardous materials production of secondary waste streams.
Recycling of Printed Circuit Board
Printed circuit boards (PCBs) can be found in any piece of electrical or electronic equipment: nearly all electronic items, including calculators and remote control units, contain large circuit boards; an increasing number of white goods, as washing machines contains circuit boards for example in electronic timers. PCBs contain metals, polymers, ceramics and are manufactured by sophisticated technologies.
All electric and electronic equipment, and have revolutionized the electronics industry. Printed circuit boards (PCBs) are used to mechanically support and electrically connect electronic components using conductive pathways, tracks or signal traces etched from copper sheets laminated onto a non-conductive substrate, employed in the manufacturing of business machines and computers, as well as communication, control and home entertainment equipment.
Composition of Printed Circuit Board
PCBs are platforms on which integrated circuits and other electronic devices and connections are installed. Typically PCBs contain 40% of metals, 30% of organics and 30% ceramics. Bare PCB platforms represent about 23% of the weight of whole PCBs. However there is a great variance in composition of PCB wastes coming from different appliances, from different manufacturers and of different age.
PCBs contain large amount of copper, solder and nickel along with iron and precious metals: approximately 90% of the intrinsic value of most scrap boards is in the gold and palladium content. However the board laminate mainly consists of a glass fibre reinforced thermosetting matrix which actual legislation imposes to be also conveniently recycled or recovered.
Characteristics of PCB Scrap
PCB scrap is characterised by significant heterogeneity and relatively high complexity, albeit with the levels of complexity being somewhat greater for populated scrap boards. As has been seen in respect of materials composition, the levels of inorganics, in particular, are diverse, with relatively low levels of precious metals being present as deposited coatings of various thicknesses in conjunction with copper, solders, various alloy compositions, non-ferrous and ferrous metals. In spite of the inherent heterogeneity and complexity, there are differences in the intrinsic physical and chemical properties of a broad spectrum of the materials and components present in scrap PCBs, and indeed electronic scrap as a whole, to permit recycling approaches in separating such into their individual fractions.
Chemical Reactivity
Hydrometallurgical approaches depend on selective and non-selective dissolution to realise a complete solubilisation of all the contained metallic fractions within scrap PCBs. Whilst all hydrometallurgical approaches clearly benefit from prior comminution, such is primarily undertaken to reduce bulk volume and to expose a greater surface area of contained metals to the etching chemistry. Selective dissolution approaches may utilise high-capacity etching chemistries based on cupric chloride or ammonium sulfate for copper removal, nitric acid-based chemistries for solder dissolution and aqua regia for precious metals dissolution, whilst non-selective dissolution may be carried out with either aqua regia or chlorine-based chemistry.
PCB Recycling of the Metal Fraction
Despite the fluctuant average scrap composition amongst the various WEEE, cell phones, calculators and PCB scraps reveal that more than 70% of their value depends on their high content in metals. Metallurgical recovery of metals from WEEE is therefore a matter of relevance and underlining three possible approaches: Pyrometallurgy, Hydrometallurgy and Biometallurgy.
Pyrometallurgy
Some techniques used in mineral processing could provide alternatives for recovery of metals from electronic waste. Traditional, pyrometallurgical technology has been used for recovery of precious metals from WEEE to upgrade mechanical separation which cannot efficiently recover precious metals. In the processing the crushed scraps are burned in a furnace or in a molten bath to remove plastics, and the refractory oxides form a slag phase together with some metal oxides. Further, recovered materials are retreated or purified by using chemical processing.
Hydrometallurgy
A bench-scale extraction study was carried out on the applicability of hydrometallurgical processing routes to recover precious metals from PCBs in mobile phones. An oxidative sulfuric acid leach dissolves copper and part of the silver; an oxidative chloride leach dissolves palladium and copper; and cyanidation recovers the gold, silver, palladium and a small amount of the copper. To recover the metals from each leaching solution, precipitation with NaCl was preferred to recuperate silver from the sulfate medium; palladium was extracted from the chloride solution by cementation on aluminum; and gold, silver and palladium were recovered from the cyanide solution by adsorption on activated carbon. The optimized flowsheet permitted the recovery of 93% of the silver, 95% of the gold and 99% of the palladium.
Biometallurgy
Biotechnology is one of the most promising technologies in metallurgical processing. Microbes have the ability to bind metal ions present in the external environment at the cell surface or to transport them into the cell for various intracellular functions. This interaction could promotes selective or non-selective in recovery of metals. Bioleaching and biosorption are the two main areas of biometallurgy for recovery of metals. Bioleaching has been successfully applied for recovery of precious metals and copper from ores for many years.
Recycling and Recovery of the Non-Metallic Materials
According to their applications and properties, synthetic polymers can be classified as plastic, rubber, fiber, adhesive, etc. Plastics include thermoplastic plastics and thermoset plastics. Plastics consist of resin, filler and addition agents. In general, the fillers for polymers have two functions: one is to reduce the cost of the products, and the other is to enhance the performance of the products. Sometimes the properties of fillers are crucial to the performance of polymer products, especially for composites. The invention of glass fiber reinforced composites has great influence on space aeronautical industry and other industries. Nowadays, superior performance fillers play a key role in high-tech material areas. Therefore, how to take advantage of filler for polymer products is a significant topic.
Recycling of Liquid Crystal Display
Liquid Crystal Display (LCD) has given a new demarcation to the display devices and have become the dominant technology in televisions and monitor in our homes and offices. The liquid crystals are used to display image in thin, light computer. It has replaced conventional cathode ray tube (CRT) monitors. The CRTs were preferred for their superior colour presentation by graphics and photography professionals. The constant improvements in LCDs technology have, however, made the performance nearly comparable and the differences less noticeable. However, as yet the electronic recycling industry has only received low volumes of LCDs are still in their working phase.
LCD monitors are apparently projected as environmental friendly, energy efficient in comparison to lead subjugated CRT models. However, LCD displays fail to reduce the impacts of mercury and arsenic which have serious concerns to environment and human health. Mercury is hazardous and requires special mandatory disposal mechanism in various countries.
Barriers to Recycling of LCDs
LCDs in common with CRTs are classed as hazardous waste under the WEEE Directive. The Directive requires that this form of WEEE must be separately collected and that hazardous components listed in the Directive’s Annex II must be removed during treatment.
Manual Disassembly Processing for LCDs
The release of mercury from lamp breakage is a primary environmental concern for approved authorised treatment facilities (AATF) engaged in LCD recycling. With little data on the fate of mercury released from CCFL lamps available to the recycling industry, it has been reluctant to tackle end-of-life LCD disassembly, preferring in many instances to stockpile waste LCDs pending a recycling solution.
The need for mercury protection is not limited solely to the disassembly process of LCDs but extends in both directions in the waste hierarchy from upstream LCD collection to downstream final recovery or disposal of components. The collection of damaged equipment with broken backlights from a designated collection facility to the delivery of mercury bearing lamp waste for specialist mercury recovery are potential mercury release issues for the industry AATF. The development of an environmental management protocol (EMP) extending from the AATF to include all stakeholders involved in the logistics of waste LCD recycling is therefore a key factor in mitigating mercury release.
Hazardous Materials in Liquid Crystal Displays (LCDs)
The EU WEEE Directive classes LCD equipment as hazardous, requiring selective removal and treatment of components listed in Annex II of the Directive. These components are as follows:
• LCD panels with a surface area MOO cm2;
• mercury-containing backlights;
Hazardous Gases
LCD display cannot be considered as green product. Various hazardous gasses are used in manufacturing the products. Some of the gases and chemicals used for manufacturing process of LCD, are potentially dangerous. The TFT-LCD manufacturing processes utilize significant amount of gases for thin-film deposition and etching. These include silane, phosphine, ammonia, and hydrogen for polycrystalline silicon and silicon nitride thin film deposition in a plasma-enhanced chemical vapor deposition (PECVD) reaction chamber. In addition, nitrogen trifluoride or fluorine is used in the PECVD chamber cleaning. Chlorine and sulfur hexafluoride are used in the dry etching of thin film. The hazards of these gases can be classified as pyrophoric, flammable and oxidizing gases.
Cell Phones Recycling
Rapid technology change, low initial cost, and even planned obsolescence have resulted in a fast-growing surplus, which contributes to the increasing amount ofelectronic waste around the globe. Recyclers consider electronic waste a “rapidly expanding” issue.
A cell phone’s shelf life is only about 24 months for the average consumer. This means that newer cell phone models are constantly put up on the market to replace older ones. This is as a result of the rapid progression of technology in the mobile industry. According to Matt Ployhar of Intel, the industry is rapidly evolving, possibly even at “Moore’s law pace or faster.” This means that newer cell phone models are continually on the rise of consumerism and more outdated models are likely to end up in landfills.
A Cell Phone Contains Just a Few Individual Parts
• A circuit board containing the brains of the phone
• An antenna
• An Liquid Crystal Display (LCD) screen
• A keyboard
• A microphone
• A speaker
• A battery
Harmful Substances in Mobile Phones
Chemicals released from mobile phones in landfill can include antimony, arsenic, beryllium, copper, lead, nickel, mercury, manganese, lithium, zinc and cadmium. Even in small amounts, these hazardous chemicals can cause environmental contamination, affecting waterways and wildlife. They can also cause a variety of serious health issues in humans if released into the environment.
Cadmium
This poisonous heavy metal is known to cause lung and prostate cancer, and is toxic to the gastrointestinal tract, the kidneys, and the respiratory, cardiovascular and hormonal systems. Cadmium is considered the seventh most dangerous substance known to humankind.
Lead
Lead is a suspected carcinogen, a known hormone disruptor, and can damage almost every organ and system in the human body, particularly the nervous system. Lead has been indicated as a cause of decreased mental ability, developmental delays, behavioural disorders and reproductive defects.
Mercury
When inorganic mercury enters the environment, it is deposited in soil and water. Micro-organisms transform inorganic mercury into organic mercury compounds, such as methylmercury. Methylmercury can bioaccumulate in the fatty tissues of living organisms, particularly fish living in polluted waters, and the people who then eat those fish. Mercury is a recognized developmental toxin, and it is also a suspected hormone disruptor, neurotoxin, reproductive toxin and respiratory toxin.
Reuse of Phones
As mentioned earlier, there are two opportunities for phone reuse: reuse “as is” and “refurbish.” Some of the EoL phones go through data clearance and basic functional and cosmetic tests. If a phone passes the test, it will be reused “as is tested.” If it does not pass the test and requires repair, it will be refurbished as long as it is economical. Obviously, refurbishment is viable only if the expected resale value is higher than the cost of refurbishment process, which is much longer than the reuse process. Some phones are not tested at all and are just sold as “untested.”
Recycling of Materials
Recycling is defined as the processes for material recovery. Technically, all materials that are present in a given feedstock can potentially be recovered, but it does not usually happen in reality. Usually only the materials that bring economic profit are recovered. In the case of cell phones, the profitable materials are precious metals and some base metals including copper. Therefore, unless otherwise stated, “recycling” or “material recovery” in this paper means precious metals and copper recovery. Generally, intermediate or secondary e-waste recyclers collect and pre-treat EoL cell phones, then send them to large-scale primary metal smelters and refineries for metal recovery.
Battery Recycling
Batteries are the power source for portable electrical and electronic devices, hence the use and discharge of batteries is growing all over the world along with such devices. Batteries are part of a variety of electrical and electronic devices such as personal computers, mobile phones, laptops, toys, cordless phones, tools, etc.
Although batteries are a component of electrical and electronic equipment (EEE) they must be recycled separately. They might be removable or fixed inside EEE, but should be disassembled and recycled by specific processes. Consumers and recyclers might not be aware of the existence of built-in batteries. The separation of the batteries from the EEE is costly because it is done manually, nevertheless the recyclers should not neglect this important operation.
Main Processing Routes
Battery recycling processes are composed basically of two main steps: waste preparation and metallurgical processing. The waste preparation step begins with the screening of the waste, segregating it by chemical type. The sorting might be composed of several steps in order to improve the separation efficiency. These steps might contain manual segregation and segregation using pieces of equipment developed specially for this operation. The pieces of equipment developed to this end apply several techniques, for example: mechanical separation, magnetic separation, X-ray images, optical sensors to read bar codes located on the waste material.
Pyrometallurgical Route
Pyrometallurgy is characterized by the use of high temperature processes. Hence, the pyrometallurgical recycling processes use high temperature to process wastes aiming at the reclamation of the target metals. During heat treatment of battery waste, several reactions may take place such as decomposition of compounds, reduction and evaporation of metals or compounds.
All pyrometallurgical processes for the recycling of batteries have in common the evaporation of a metal to segregate it from the other materials that have higher boiling points. Therefore, the goal of these processes is to evaporate Hg, Zn and/or Cd.
Technical Steps in Battery Recycling
In developing countries lead-acid battery scrap is normally processed in rotary drum furnaces using liquid fuel as energy source. Lead bearing feed materials are either whole battery packs (grids and paste) where the separators have been removed or two separate fractions a) grid metal only and b) paste and other fines
Dismantling of Battery Cases and Feed Preparation
Used batteries are emptied by hand and the acid is collected in plastic barrels. If the full barrels are kept motionless for some time, solid impurities will settle at the bottom of the barrels. This process of sedimentation may be assisted by adding some flocculent. The purified acid is then decanted and packed for sale. Possible customers for the recycled acid is the mining and metallurgical industry which uses acid in various leaching operations. The remaining battery sludge is neutralised with lime. After passing through a filter press the filter cake may be charged together with the fine fraction into the melting and reduction furnace.
Melting and Reduction Operation of Paste and Battery Fines
The filter or sun baked cake of paste is charged to a short rotary drum furnace where the charge is melted together with slag forming constituents (soda ash = Na2CO3) and reaction additives (Fe-swarf, coal).
Depending on the temperature and the amount of feed material in the furnace, the reaction time will be 2-3 h. Due to the difference in specific weight the molten lead produced settles at the bottom part of the furnace. When enough lead has accumulated, it is tapped into a mobile ladle and transported in liquid stage to the refining kettle.
Melting of Grids, Terminals and Bridges
The coarse fraction of the crushed battery scrap is fed to a crucible furnace, melting kettle or rotary drum furnace. By adding a bit of soda ash the charge is melted and stirred for some while. During this operation insoluble impurities will settle on top of the melt and join the soda ash slag, which is skimmed off at the end of the melting operation. Gases and flue dust from the process are soaked away and passed over to the gas cleaning system.
Refining of Crude Lead
First, the lead tapped from the furnace has to be cleaned from residual oxides and slag. For that purpose a bit of pitch and saw dust is added. After stirring for a while the impurities settle at the surface and are skimmed off.
Crude lead originating from battery scrap is normally alloyed with copper and antimony (with traces of Ca, Sn, As, Zn). In order to remove the unwanted elements two further refining operations have to be carried out.
Gas Cleaning System
Due to the lack of environmental legislation and monitoring, and due to lack of funds industrial operations in developing countries often have very poor emission control and off-gas cleaning systems. Because of the hazardous potential of the majority of the elements and compounds which are involved in lead smelting and refining (Pb, Sb, As, SO2, etc.), a certain gas cleaning standard must be achieved and should be compulsory.
Computer Recycling
A computer is a general purpose device that can be programmed to carry out a set of arithmetic or logical operations automatically. Since a sequence of operations can be readily changed, the computer can solve more than one kind of problem.
Computer recycling is the recycling of computers and any other electronic devices. Recycling is the complete deconstruction of electronic devices in order to cut down on mining the raw materials and rather extract the materials from old and obsolete electronics. With technological developments taking place at such a fast pace today, our electronic devices, especially our personal computers, become obsolete very quickly.
Composition of Computer
Computers contain substantial amounts of substances that are harmful to the environment and living things. The following are some of the well-known and potentially dangerous substances:
• brominated flame retardants: used in the plastic cases and cables of computers to reduce the flammability of the electronic set, and has been found to affect nervous system, thyroid and liver health in both humans and animals;
• lead: used in cathode ray tube (CRT), glass in computer monitor, as well as in soldering of parts in the computer, and has been found to cause damages to the nervous and brain system;
• mercury: used in flat screen monitors, fluorescent tubes etc, and has been found to reduce mental abilities, fertility and even cause death.
Recycling Process of Computers
The computer recycling process follows the general process of recycling - collection, sorting, processing and use in the manufacture of new products that are then purchased by consumers.
Collection
This stage of the process of recycling computers involves the transfer of the unwanted computer from its owner to the recycling company. In the first step of the recycling process, the recyclables materials are collected. The methods of collection may vary from community to community. There are several different ways by which recyclables can be collected from households, offices etc, for recycling.
Removing the Large Objects
The commingled recyclates are first spread out. Machineries like the conveyor belt may be used. Large pieces of cardboard or plastic bags are easily removed by hand. Removing these large objects also prevent them from jamming the machineries that may be used later down the line.
Manual Disassembly
If the cost of refurbishing a particular set greatly outweighs the expected selling price of a functional computer set, then that set is most likely to be taken apart into its basic components, for example, the hard disks, DVD drives, modem, speakers, sound or graphic cards, etc. This disassembly process is usually carried out manually, by trained personnel so as to protect the usability of the components.
The functioning components are then sold, for example to consumers looking for good second hand deals, or even to computer manufacturers for refurbishment and use in the manufacture of computer sets.
Separation into Material Composition
With the reusable and hazardous components of the computer sets removed, the remains of the computer sets are further broken down by material composition, for example, plastic (e.g casing), wires, metals, circuit boards etc, in the process of recycling computers.
Disposal of Non-Recyclable Parts
Whatever remains that cannot be recycled are then disposed of - sent to a landfill or incinerator.
Purchase of Products Made of Recycled Materials
For the recycling loop to be closed there must be demand for goods that are made from recycled materials or items. That means that the process of recycling computers must include this final stage where computer sets, assembled using refurbished computer components, or made out of recycled computer materials, are being marketed and sold in the market, and finally purchased by consumers.
Restriction of Hazardous Substances Directive
The RoHS Directive stands for “the restriction of the use of certain hazardous substances in electrical and electronic equipment”. This directive is only practiced in the European Union. A RoHS compliant product means that electrical and electronic equipment cannot contain more than maximum permitted levels of lead, cadmium, mercury, hexavalent chromium, polybrominated biphenyl (PBB) and polybrominated diphenyl ether (PBDE) starting on July 1, 2006.
The RoHS Directive and Proscribed Materials
The RoHS Directive proscribes substances that are hazardous and that pose serious environmental problems during the disposal and recycling of WEEE. In line with the similar requirements of the End-of-Life Vehicles Directive, the targeted substances are the heavy metals mercury, lead, cadmium and hexavalent chromium, as well as polybrominated biphenyls (PBBs) and two polybrominated diphenyl ethers (PBDEs).
Lead
The proscription of lead has caused significant concerns for electronics manufacturers. Although there are numerous ‘lead-free’ solders available, there are many issues that need to be addressed before they can be successfully implemented as viable alternatives. These issues include, amongst others, the compatibility of new solders with printed circuit board and component finishes, the ability of existing materials and equipment to handle higher soldering temperatures and the selection and supply of components that can survive higher soldering temperatures and give long-term reliability.
Brominated Flame Retardants
Brominated flame retardants, in isolation or in combination with antimony trioxide, perform a valuable function in preventing fires and it is important to note, therefore, that the RoHS Directive does not proscribe the use of all brominated flame retardants but just two particular types. These are poly-brominated biphenyls and two examples of the polybrominated diphenyl ethers.
Cadmium, Mercury and Hexavalent Chromium
These three metals can occur in a wide range of applications in electronics and in this respect they are perhaps more troublesome from a compliance perspective since there are so many potential, and sometimes unexpected, applications.
List of categories of equipment that will need to comply with RoHS legislation.
The list of products below each category heading is illustrative and not exhaustive.
• Consumer equipment Such as radio sets; television sets; video cameras; video recorders; hi-fi recorders; audio amplifiers; musical instruments; other products or equipment for the purpose of recording or reproducing sound or images, including signals or other technologies for the distribution of sound and image than by telecommunications.
• Lighting equipment, (including electric light bulbs and household luminaires) Such as luminaires for fluorescent lamps; straight fluorescent lamps; compact fluorescent lamps; high intensity discharge lamps, including pressure sodium lamps and metal halide lamps; low pressure sodium lamps; other lighting equipment for the purpose of spreading or controlling light.
• Automatic dispensers Such as automatic dispensers for hot drinks; automatic dispensers for hot or cold bottles or cans; automatic dispensers for solid products; automatic dispensers for money; all appliances which deliver automatically all kind of products.
Benefits ROHS
RoHS helps reduce damage to people and the environment in third-world countries where much of today’s “high-tech trash” ends up. The use of lead-free solders and components has provided immediate health benefits to electronics industry workers in prototype and manufacturing operations. Contact with solder paste no longer represents the same health hazard as it used to.
E-Waste Rules by Ministry of Environment and Forests
MODIFIED DRAFT NOTIFICATION
S.O. ( ):- Whereas, the draft rules, namely the e-waste (Management and Handling) Rules 2010 was published by the Government of India in the Ministry of Environment and Forests vide number S.O.1125 (E), dated 14th May, 2010 in the Gazette of India, Extraordinary of the same date inviting objection and suggestion from all persons likely to be affected thereby, before the expiry of the period of sixty days from the date on which copies of the Gazette containing the said notification were made available to the public;
RESPONSIBILITIES
Responsibilities of the producer. - the producer shall be responsible for;-
(1)collection of e-waste generated during the manufacture of electrical and electronic equipment and channelizing the same for recycling or disposal.
(2)Collection of e-waste generated from the ‘end of life’ of their products in line with the principle of ‘Extended Producer Responsibility’ (EPR), and to ensure that such e-wastes are channelized to registered refurbisher or dismantler or recycler.
(3) setting up collection centers or take back system either individually or collectively for all electrical and electronic equipment at the end of their life.
Responsibilities of Distributers
(1)Every distributer shall be responsible to collect the e-waste by providing the consumer(s) a box, bin or a demarcated area to deposit e-waste.
(2)Every distributer shall make an application in Form 4 to the concerned State Pollution Control Boards or Pollution Control Committees for grant of one time registration;
(3) Every distributer shall ensure that the e-waste thus collected is safely transported back to the producer or to authorized collection centre as the case may be.
Responsibilities of refurbisher–
(1)Every refurbisher shall collect e-waste generated during the process of refurbishing and channelized the waste to producer or authorized collection center or dismantler or recycler.
(2) Every refurbisher shall file annual returns in Form 3 to the concerned State Pollution Control Board or Pollution Control Committee, on or before the 30th day of June following to the financial year to which that return relates.
Responsibilities of collection centers – Any person(s) operating collection centre(s) individually or collectively shall,-
(1)obtain an authorization in accordance with the procedures prescribed under Rule -11 from the concerned State Pollution Control Board or Pollution Control Committee as the case may be and provide details such as address, telephone numbers/helpline number, e-mail, etc. of such collection centre(s) to the general public.
(2) ensure that the e-waste collected by them are stored in a secured manner till these are sent to producer(s) or refurbisher or registered dismantler(s) or recycler(s) as the case may be;
Responsibilities of consumer or bulk consumer.-
(1)Consumers of electrical and electronic equipment shall ensure that e-waste are deposited with the distributer or authorized collection centers.
(2) Bulk consumers of electrical and electronic equipment shall ensure that e-waste are channelized to distributer or authorized collection centers or refurbisher or registered dismantler or recyclers or avail the pick-up or take back services provided by the producers; and
Environmental Aspects
The electronic industry is the world’s largest and fastest growing manufacturing industry during the last decade; it has assumed the role of providing a forceful leverage to the socio - economic and technological growth of a developing society. The consequence of its consumer oriented growth combined with rapid product obsolescence and technological advances are a new environmental challenge - the growing menace of “Electronics Waste” or “e waste” that consists of obsolete electronic devices. The discarded and end-of life electronics products ranging from computers, equipment used in Information and Communication Technology (ICT), home appliances, audio and video products and all of their peripherals are popularly known as Electronic waste (E-waste). E-waste is not hazardous if it is stocked in safe storage or recycled by scientific methods or transported from one place to the other in parts or in totality in the formal sector.
Effects on Environment and Human Health
Disposal of e-wastes is a particular problem faced in many regions across the globe. Computer wastes that are landfilled produces contaminated leachates which eventually pollute the groundwater. Acids and sludge obtained from melting computer chips, if disposed on the ground causes acidification of soil. For example, Guiyu, Hong Kong a thriving area of illegal e-waste recycling is facing acute water shortages due to the contamination of water resources.
Impact of Hazardous Substances on Health and Environment
The waste from electronic products include toxic substances such as cadmium and lead in the circuit boards; lead oxide and cadmium in monitor cathode ray tubes (CRTs); mercury in switches and flat screen monitors; cadmium in computer batteries; polychlorinated biphenyls in older capacitors and transformers; and brominated flame retardants on printed circuit boards, plastic casings, cables and PVC cable insulation that releases highly toxic dioxins and furans when burned to retrieve copper from the wires. Many of these substances are toxic and carcinogenic. The materials are complex and have been found to be difficult to recycle in an environmentally sustainable manner even in developed countries.
Responsibility and Role of Industries
Generators of wastes should take responsibility to determine the output characteristics of wastes and if hazardous, should provide management options. All personnel involved in handling e-waste in industries including those at the policy, management, control and operational levels, should be properly qualified and trained. Companies can adopt their own policies while handling e-wastes.
Responsibilities of the Citizen
Waste prevention is perhaps more preferred to any other waste management option including recycling. Donating electronics for reuse extends the lives of valuable products and keeps them out of the waste management system for a longer time. But care should be taken while donating such items i.e. the items should be in working condition. Reuse, in addition to being an environmentally preferable alternative, also benefits society. By donating used electronics, schools, non-profit organizations, and lower-income families can afford to use equipment that they otherwise could not afford. E-wastes should never be disposed with garbage and other household wastes. This should be segregated at the site and sold or donated to various organizations.
