March 15th, 2018
Design Life Cycle of a Hot Wheels Car
The embodied energy used during the life cycle of Hot Wheels cars consists of thermal, electric, human, gravitational, chemical, and mechanical energy. Not much energy is used to create the cars themselves but, there is an abundance of energy indirectly being used by primary and secondary sources during the extraction of raw materials being used in the die-casts of Hot Wheels cars, as well as their transportation across the world. The making and designing of a Hot Wheels car in terms of energy is rather environmentally beneficial, however, the extraction of raw materials and their transportation methods contribute to large scale energy consumption and world pollution.
The first part of the life of a Hot Wheels car is the extraction of its main raw material, Zamak3 (Zinc (Zamak) Alloys). Zamak3 is an acronym for the alloying of Zinc, Aluminum, Magnesium, and Copper, however, the Hot Wheels cars have traces amounts of lead, tin, and cadmium due to the extraction of the main raw materials before the alloying process (Zinc (Zamak) Alloys). The main way each of these raw materials are extracted are open-pit and underground mining (Open Pit Mining). The U.S. mining industry (excluding oil & gas) consumes approximately 1,246 Trillion Btu/year (TBtu/yr). The acronym “TBtu” stands for “Trillion British thermal unit”, which is the unit used to measure thermal energy (Open Pit Mining). Underground mining requires more energy than surface mining due to greater requirements for hauling, ventilation, water pumping, and other operations during the mining process, as shown below (Open Pit Mining). Both methods are used to extract the metals used in Hot Wheel cars. Both methods are used to extract the metals used in Hot Wheel cars. Additionally,
The first main metal mining extraction technique is drilling; drilling is making a cylindrical hole with a tool for the purpose of exploration, blasting preparation, or tunneling (Open Pit Mining). Drills are run from the secondary energy source electricity, primary source diesel, and indirectly from the primary source of compressed air (Open Pit Mining). The energy is used to power parts of the drill that hammer and rotate (Open Pit Mining). This method contributes to world pollution because the drilling machines collectively release large amounts of CO2. The second metal mining extraction technique is Blasting, which uses explosives to fracture rock and ore by the chemical energy released during the blast (Open Pit Mining). Though blasting contributes greatly to air pollution as it releases a considerable amount of carbon dioxide, carbon monoxide, oxides of nitrogen, ammonia, and sulfur dioxide (Open Pit Mining). It also reduces the oxygen concentration in the air (Open Pit Mining).
The third metal mining extraction method is Digging which uses mechanical energy to make passage ways or to remove material from the earth (Underground Mining Process). The goal of digging is to extract as much valuable material as possible and reduce unwanted materials (Underground Mining Process). The fourth extraction method is Ventilation which is among the most important because it keep the mine site safer. It brings fresh air into the underground mine and removes stale and/or contaminated air (Open Pit Mining). It also cools the work areas of deep underground mines (Underground Mining Process). This process usually uses mechanical wind energy with fan systems (Underground Mining Process); this method indirectly contributes to air pollution by using a secondary energy source (electricity) to keep it up and running. The coal being burned to power the electricity being used by the fan system releases large amounts of CO2 into the air.
The fifth and last metal mining extraction method is dewatering, the flushing of water into mine workings. This is a large energy consumer because the pumps use great amounts of electric energy, which adds to air pollution as a secondary energy source (burning coal being the primary), to power them (Underground Mining Process). This also contributes to water pollution because tailing ponds built for contaminated water leak occasionally into streams and lakes nearby (Open Pit Mining). Even with secure tailing ponds, contaminated water that meets “water quality guidelines” is allowed to be discharged into surface water (Underground Mining Process). Some general mechanical energy comes from diesel powered rubber tire or track vehicles that deliver material in batches and electric energy that powers continuous delivery systems such as conveyors and slurry lines (Underground Mining Process). A lot of the diesel equipment account for 87% of the total energy consumed in materials handling due to diesel engines (Underground Mining Process). Equipment includes service trucks, front-end loaders, bulldozers, bulk trucks, rear-dump trucks and ancillary equipment such as pick-up trucks and mobile maintenance equipment (Underground Mining Process). These also contribute to air pollution because of the CO2 being released from each machine. Moreover, ores are rarely found freely in nature and are typically extracted as compounds. These compounds prevent the ore’s from being in their purest form so after extraction, the ores are processed to try and get them as pure as possible. These processes unfortunately also contribute to large scale energy consumption and air and water pollution.
The first stage of metal processing is Crushing which is the process of reducing the size of mine material into coarse particles using mechanical energy from machines that run on fuel which emit CO2 (Open Pit Mining). Next is Grinding, the process of reducing the size of material into fine
(Open Pit Mining). A lot of heat energy is lost in the grinding balls being used to grind the ores as depicted below (Underground Mining Process). The grinding mills contribute about the same about of CO2 emissions ascrushing machines due to them both being powered by the secondary source, electricity. machines due them both being powered by the secondary source electricity. Mined material is usually separated physically rather than chemically (Open Pit Mining). Various types of equipment are used for this separation process. The largest energy-consuming separation method is floatation for metal mining (Open Pit Mining). Flotation machines are designed to isolate valuable ore from impurities (Open Pit Mining). The surfaces of mineral particles are, “treated with chemicals that bond to the valuable product and make them air-avid and water-repellent. The ore is suspended in water that is mechanically agitated and aerated. The treated minerals attach to air bubbles and rise to the surface where they can be collected.” Final processing further prepares the ore to become the desired product in its purest and most valuable form. Roasting, smelting, and refining are different processes falling under this category. Roasting and Smelting both require thermal energy, and refining is mechanical energy. When energy requirements for each of these methods are broken down we see the energy needed for an open pit mine is calculated as 11,766 kWh/kiloton. The average energy needed for an underground mine is 10,241 kWh /kiloton (Open Pit Mining).
thermal energy (Alloying Casting Rolling and Slitting). After an induction furnace is used, the alloy is poured into bars or ingots for future use; the process requires close control to avoid contaminates and oxidation (Alloying Casting Rolling and Slitting). Another method is the casting process which uses thermal energy to re-melt the alloyed material and converts the alloy’s liquid state to a cast strip or rod (Alloying Casting Rolling and Slitting). “The casting process requires a starting bar for the liquid metal to cling to; once the starting bar is in place, it draws the liquid metal through a die to form cast strip or rod with the proper cross sectional dimensions” (Alloying Casting Rolling and Slitting). After this step comes rolling; rolling uses mechanical energy to reduce the thickness of die-cast strip to the final size required to stamp the alloy (Alloying Casting Rolling and Slitting). Metal is fed through the rolling mill at a specific temperature, pressure and speed to ensure creating the final desired form (Alloying Casting Rolling and Slitting). Next comes slitting, once the rolled strip has reached a certain thickness and hardness, the material is slit to the desired width and cut to the necessary length (Alloying Casting Rolling and Slitting). The alloying process does contribute to air pollution because the furnace releases a lot of CO2 and Nitrogen, since these alloys are manufactured through a factory where there are likely multiple furnaces.
The Thailand plant in Bangkok is assumed to order their own alloys because they are relatively inexpensive and easy to obtain. The alloys are then melted down in house and put into the mold of the next Hot Wheels car (Diecast 101). After the mold is solidified, the cast is transferred with human energy by hand onto a tiny toy axel and wheels, then the design portion begins. The paint used on modern Hot Wheels cars is enamel paint because it dries glossy and harder than most paints (What Is Enamel Paint). Enamel paints dry glossy because they are oil based, these oils are commonly called Triglycerides (What Is Enamel Paint). There is quite a bit of chemical energy used to create enamel paint. Triglycerides are reacted using caustic soda and “saponifies” into the Fatty acids present in the oil and Glycerol (What Is Enamel Paint). Then, “polypropylene is made from the polymerization of propylene gas in the presence of a catalyst system, usually Ziegler-Natta or metallocene catalyst” (What Is Enamel Paint). The temperature, pressure and reactant concentrations are set for polymerization conditions, so the polymer grade to can be produced (What Is Enamel Paint); this process mainly uses chemical energy to bond molecules to produce a certain paint consistency (What Is Enamel Paint). Polymerization is economical and flexible; it is the most common technology in modern polypropylene production plants (What Is Enamel Paint). This is the only part of Hot Wheels car making that does not contribute to large scale energy consumption or pollution.
After a Hot Wheels car is molded, assembled, painted, and dried, it is packaged and shipped out to toy stores worldwide. The shipment of these packages does contribute to air pollution as it is assumed they are being taken by truck. When one is ready to get rid of their Hot Wheels car, they can either dispose of it in the trash or recycle it. If one simply disposes it, they are picked up by a garbage truck which uses mechanical energy, and sent to a local landfill. If recycled, the cars are picked up by a recycling truck that uses mechanical energy, and is sent to a local recycling plant to be repurposed using human and mechanical energy.
The making of one Hot Wheel car alone is very low on energy consumption, however, it indirectly contributes to a much larger scale of energy consumption and world pollution. The materials used in Hot Wheels are extracted through the mining process which has a massive energy consumption, air, and water pollution rate. Due to this, Hot Wheels cars should be bought for long time keeping because they, like many consumer goods, significantly add to environmental issues, and should be bought at a lesser rate. Individuals typically do not think about all that goes into making their common consumer goods. The embodied energy used during the life cycle of Hot Wheels cars impacts the environment quite negatively and the cars usually aren’t recycled. However, the cars themselves are not the issue, what they are made of is. Facing the reality of how much pollution and energy is being consumed by making these universally loved toys, unfortunately takes the fun out of owning them.
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15 March 2018
Hot Wheels Life Cycle: Raw Materials
Hot Wheels is an iconic American brand, known for their life-like toy cars. Some of these are based on existing car models and others formulated by the designers’ imagination. Hot Wheels was introduced by the American toy company, Mattel in 1968. These toy cars are known to be made through a process called die casting . This refers to the process of using a lead or zinc based alloy, the latter in this case, melting it down, and pouring it into a mold in order to get a desired shape or form. The specific allow used by Hot Wheels is a zinc based alloy called Zamak 3, composed of aluminum, copper, magnesium, iron, cadmium, tin and, most abundantly, zinc . Hot Wheels themselves have not made a statement about the impact of the use of these materials or their manufacturing process on the environment or the about the cars’ ability to be recycled. Based on the materials they are known to use and the well-known process of die casting, we are able to do some research and figure it out. From acquiring the raw materials, through altering them into the toy cars we are so familiar with, Hot Wheels has created a system that is efficient, minimizes waste and provides the best product using a specific combination of well thought-out materials. They have done this by strategically selecting the materials they chose to work with by way of taking into account a variety of factors including the accessibility, energy consumption and durability of the raw materials.
Hot Wheels has a raw materials supplier in China and although there is no information as to where exactly the raw materials originated from, we can assume they have been acquired internationally since certain materials are more abundant in different parts of the world. To get an idea of where all the materials are coming from, here are some of the largest suppliers for each of the required metals. The largest suppliers of aluminum are found in Russia . For copper, the largest suppliers are in Chile . Most magnesium comes from China . The country that produces the most iron is Australia . China is also where the most tin is produced . Lastly, zinc is mostly commonly produced in Korea . All these metals may have been obtained through various processes, but mainly through mining. Mattel Inc., the company that owns Hot Wheels, has a few manufacturing plants across eastern Asia so once the raw materials have been secured, they are distributed among those locations via cargo ships . The main raw material involved in cargo shipments is the fuel needed to power the ship. Cargo ships use a gas called bunker fuel. This fuel contains even more sulfuric content than diesel, which is necessary to power such a large vehicle .
As mentioned earlier, Hot Wheels uses a zinc based, Zamak 3 alloy to create their toy cars. Aluminum, making up 8.1% of the Earth’s crust, is the most prevalent metal in the Earth’s crust and so is one of the most accessible raw materials needed for the Zamak 3 alloy . Similarly, copper is also reasonably attainable through mining. Magnesium, also relatively abundant, is most commonly found and extracted from seawater. Iron is another common and inexpensive metal found in the Earth’s crust. Unlike the metals previously mentioned, cadmium is more limited and difficult to mine due to it being poisonous. There is not much tin in the Earth’s crust, but it is accessible by heating cassiterite (SnO2) with carbon. Lastly, the most prevalent metal in the Zamak 3 alloy, Zinc, is obtained through the electrolysis of aqueous zinc sulfate (ZnSO4) .
Once the plant has the primary raw materials, their next step is to transform it into the secondary raw material, the Zamak 3 alloy. Assuming Hot Wheels produces their own alloy, this is done by heating the metals in a furnace at 384 degrees Celsius. This is done in order to melt down the metals and combine them to form the alloy. Once the alloy is complete, it goes through a process called hot chamber die casting as opposed to cold chamber die casting . In this process, the molten metal is added to the furnace part of the die casting machine in order to keep it hot enough to remain in its liquid phase. Then, a plunger pushes the molten metal from the furnace, through a pipe and into the mold . The molten alloy fills the mold and once the metal cools in the mold you have the frame for the Hot Wheels car. Hot Wheels most likely chose to use this specific zinc alloy because it is known for its relatively low casting temperature, which means it does not require as much energy input, making it better for the environment and easier for them produce. This also allows for more resistance towards corrosion in the long run as well as a stronger, more durable finish .
The manufacturing process is still far from complete once the mold is finished. Next, manufacturers go through a process of trimming and painting. Trimming refers to smoothing out the edges and getting the exact desired shape. After that, Hot Wheels uses enamel paint, known for its hard, glossy finish. This notable finish is due to its either alkyd resin or nitrocellulose base, which both provide a shiny, smooth finish . Some of the raw chemicals found in the alkyd resin base include glycerol (C3H8O3), phthalic anhydride (C8H4O3), isophthalic acid (C8H6O4), pentaerythritol (C5H12O4), and terephthalic acid (C8H6O4) . Nitrocellulose is made up the following raw materials: etanol (C2H6O), defatted cotton, nitric acid (HNO3) and sulfuric acid (H2SO4) .
As mentioned earlier, Hot Wheels nor Mattel has made an absolute statement about the recyclability or environmental impact of their product, but using the information on the materials and processes that Hot Wheels uses we can make a few hypotheses. According to a paper from the Massachusetts Institute of Technology, “the inclusion of 28% scrap metal in die cast metal input greatly reduces the environmental footprint”, which indicates that Hot Wheels could be reusing discarded metals in order to make their zinc alloy . If this is the case, it would be a great deal better for the environment considering the metals that Hot Wheels need, although currently abundant, are not considered renewable sources. In addition, zinc, the most prevalent metal in the Zamak 3 alloy is recyclable, although it does have to go through a reclamation process to separate it from other metals . The second most abundant raw metal in the Zamak 3 alloy is aluminum, which can also be recycled into items like cans and foil. According to The Aluminum Association, “nearly 75 percent of all aluminum produced in the U.S. is still in use today” . Copper, the third most present metal in the alloy is also highly recyclable. The Copper Development Association Inc. states that, “only about 0.7 trillion pounds (12%) have been mined throughout history... and nearly all of that is still in circulation, because copper's recycling rate is higher than that of any other engineering metal” . The rest of the metals in Zamak 3 make up less than 0.2% of the alloy . By examining the main components of the alloy, we found that it is over 99% recyclable. This all depends on how consumers decide to dispose of their Hot Wheels cars though. If taken to a local scrap metal recycling plant, they would most likely be able to reclamate the metals to separate them in order to recycle and reuse them. Besides the metal frame of the car though, we have to take into consideration the recyclability of the enamel paint mention earlier. Because of enamel paint’s oil/alkyd base, it is not easily recycled and must be disposed of professionally . For this reason, the toy cars are not entirely recyclable, but do have recyclable components.
The process of researching the Hot Wheels materials and manufacturing allows one to take note of the qualities of the raw materials they chose to work with. Taking into consideration the materials’ accessibility, energy consumption and durability it is believable that Hot Wheels, and its larger company, Mattel Inc. have tried to make the best product without taking advantage of too many of the world’s natural resources. In Mattel Inc.’s mission statement it states, “We look to reduce their environmental impact and build [toys] in facilities that adhere to high standards. We are committed to strong ethical and environmental performance both within our company and in our communities” . Their intentions sound like they are coming from a good, honest place when making this statement, but that is not to say there are not areas where they could make improvements. When it comes to raw materials, each metal does provide a service and play a role in the quality of the finished product, but there could be testing done to find a suitable, more sustainable alternative. Although it may cost more, Mattel Inc. has a net worth of nearly $6 billion and if they claim have the environment in mind, that is a price they should be willing to pay. In addition, the cargo ships use bunker fuels, which pollute the air and can harm many lifeforms in the long run. Mattel Inc. is not a malicious company as there are plenty that make negative impact on our environment, but all we can ask of them is to be aware and make conscious efforts to be better.
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March 2, 2018
Pollution Associated with Hot Wheels Manufacturing.
The average consumer is unaware of the environmental impacts caused by the products they purchase. The life cycle analysis is a way to educate consumers on the impact caused to the environment by specific products. This analysis is essential because it allow consumers to make an informed decision about the products they purchase. Through my research on the life cycle of a Hot Wheels model 1971 Ford Mustang Mach 1 (red), I discovered the large amounts of pollution it causes.
The life cycle of a Hot Wheels car goes through four major steps (excluding retail): extraction and transportation of the raw materials, die-casting, and disposal. Within these major steps there are a few subcategories that we will examine as well. I will list the pollution caused by each of these steps and how they impact our environment.
The Primary material used to make this Hot Wheels model is a die-casting alloy called Zamak 3 (sometimes spelled Zamac). An alloy is a mixture of two or more metals to create a new metal. Zamak 3 in comprised of eight metals: aluminum, copper, magnesium, iron, lead, cadmium, tin, and zinc. The processing of each of these metals vary slightly but the steps more or less the same. Because of this; I will not discuss the processing and extraction of each metal individually as that is beyond the scope of this research paper. I will instead focus on how ore is extracted and processed and the different forms of pollution that are caused during this process.
When metals are extracted from the ground they look a lot different from the metal that you would see for sale in a hardware store. A metal in its raw form is called ore. Ore is a “metal-bearing mineral or rock, or a native metal, that can be mined at a profit."
Once a profitable ore deposit is discovered in it is extracted through mining. There are two types of mining, surface (also known as open pit mining) and subsurface mining. Surface mining is done by using excavators, bulldozers, and other specialty machines to dig down into the earth and remove all of the soil surrounding the ore deposit. The result is a large open pit that can be hundreds of feet wide and deep. Once the pit is created, explosives are used to expose and separate the ore from surrounding sediment. Bulldozers then load the ore onto dump trucks which transport the ore out of the pit and to the processing facility. The Surrounding sediment, known as overburden, is also loaded onto dump trucks and transported to a storage facility where it will later be used to refill the mine after it has been stripped of ore. If an ore deposit is located deep in the earth, then subsurface mining is used. In subsurface mining a drill is used to dig a vertical shaft deep several thousand feet into the earth’s crust. The deep mines often run into pockets of water and often need dewatering.
Miners use jackhammers and explosives to dislodge the ore from the surrounding sediment where they are then loaded onto an elevator and brought to the surface. The method of transporting and processing is the same as with surface mining at this point. Now that a basic understanding of the extraction process has been established, we will look out how this impacts the environment.
The use of heavy duty machinery throughout all steps of mining is integral. These machines are powered by fossil fuels which emit toxic fumes into the air. A diesel bull dozer produces 127.657 tons of carbon dioxide per year (CO2 tons/yr), an excavator 21.276 CO2 tons/yr and two dump trucks produce 255.170 CO2 tons/yr (Lewis). To put this into perspective, the Environmental Protection Agency (EPA) states that the average car produces 4.75 CO2 tons/yr. This amount CO2 being released into the atmosphere greatly contributes to global warming and severe/abnormal weather. This is because the gas takes a long time to be naturally absorbed through the Earth’s natural carbon cycle. The (Environmental Protection Agency) puts the Global Warming Potential (GWP) for CO2 at 1. This means that it takes 100 years to absorb one ton of CO2 emitted into the atmosphere. By these calculations, it will take 12,765.7 years to absorb the amount of CO2 emitted by only two dump trucks over the course of a year. Hopefully I do not have to explain severity of these numbers.
Once extracted, the ore is put into a crusher that separates the valuable mineral from the invaluable sediment. According to (MIT.edu), “When crushed, these rocks expose radioactive elements, asbestos-like minerals, and metallic dust.” These toxic materials are so fine that the particles become airborne and can easily be inhaled by workers and residents in neighboring areas. Long term exposure to asbestos can cause pleural effusion, asbestosis, lung cancer, or mesothelioma (NIH.gov). The result of most of these ailments are painful death.
As the ore is crushed and separated it creates a byproduct known as tailings. Tailings are a waste material that is a mixture of water and those cancer-causing particles to make a slurry. Tailings are especially dangerous because there is no way dispose of them. In fact, miners build tailing ponds as a way to permanently store them. Tailings have been linked to metal pollution of soil. This happens because the tailing ponds can be enormous and according to (Zhou and Guo) “huge tailing ponds as a result of the accumulation of the wastes remain in the area which may extend in some cases over hundred hectares, are now abandoned without any particular safety measures and with a high environmental impact on the surrounding ecosystems and populations -.” Basically, because these tailing ponds can be hundreds of “hectares” (2.47 acres) large and are often abandoned, they began to leak into the soil and groundwater. The heavy metals pollute the soil and nearby bodies of water and can be extremely toxic to any living creature that comes in contact with this contaminated soil or water. All metal pollution can be harmful but (Zhou and Guo) discuss how Lead (Pb) and cadmium (Cd) specifically effect the environment,
Heavy metal pollution not only degrades the quality of air, water bodies, and food crops, but also threatens the health and well-being of animals and human beings through food chain  . For example, as a non-essential element to human body, the excessive intake of Pb can damage nervous, skeletal, circulatory, enzymatic, endocrine, and immune systems of those exposed to it ; chronic exposure to Cd can have adverse effects such as lung cancer, pulmonary adenocarcinomas, prostatic proliferative lesions, bone fractures, kidney dysfunction, and hypertension, while the chronic effects of As consist of dermal lesions, peripheral neuropathy, skin cancer, and peripheral vascular disease .
Hopefully you are beginning to understand some of the impacts caused to humans and the environment by the pollution associated with the extraction process.
After the raw materials are extracted and processed, they are then transported to the Mattel manufacturing plant in Thailand. Transporting these materials from all over the globe leads to a heavy carbon footprint. I was unable to find information on the exact locations of the mines from which Mattel sources their raw materials. Because of this, I will base my information of carbon emissions on the locations of the world’s leading suppliers of each metal.
The origins or each metal is as follows: aluminum: Africa, cadmium: china, copper: Chile, magnesium: China, iron: Brazil, tin: Africa, lead: Australia, zinc: Korea. Based on the weight of the necessary amount of each metal to produce thousands of cars, it is safe to assume that the metals are transported to the manufacturing facility in Thailand via cargo ship (except for the metals that originate in China which are most likely shipped by vehicle).
Bunker fuel is commonly used to power large cargo ships because of its low cost. Bunker fuel is a low-grade fuel extracted from crude oil and has a very high sulfur content. Cargo ships burn (literally) tons of this toxic fuel a day. Because fuel consumption is based on many variables (current, storms, weight of cargo, wind speed etc.) I was unable to obtain a firm average rate of fuel consumed by cargo ships per mile. At the Average speed of 18 knots, the daily fuel consumption is about 52.46 tons (Bialystocki and Konovessi). This is an astronomical amount of Sulfur Dioxide (SO2) being expelled into the atmosphere. (Evans) explains that there were approximately 90,000 vessels and 760 million cars in the world (in 2009) however, vessels produce 20 million tons of Sulfur Dioxide each year. This is “260 times more Sulphur Dioxide being emitted by ships than the worlds entire car fleet” (Evans). Sulfur Dioxide is extremely harmful to humans and (Transport and Environment) explains how,
Air pollution from international shipping accounts approximately for 50,000 premature deaths per year in Europe, at an annual cost to society of more than €58 billion according to recent scientific studies. Through chemical reactions in the air, SO2 and NOx is converted into fine particles, sulfate and nitrate aerosols. In addition to the particles directly emitted by ships such as black carbon, these secondary particles increase the health impacts of shipping pollution. Tiny airborne particles are linked to premature deaths. The particles get into the lungs and are small enough to pass through tissues and enter the blood. They can then trigger inflammations which eventually cause heart and lung failures. Ship emissions may also contain carcinogenic particles.
So not only are the emissions caused by transporting these raw materials contributing to global warming, they are also killing people.
Once the raw materials are transported to the Mattel manufacturing plant in Thailand, they are melted and combined to make Zamak alloy ingots. These ingots are used to die cast the Hot Wheels car. Die casting is the process of injecting molten metal into a reusable mold (die) and super cooling the metal (quenching) so that it retains the form of the die. There are three main steps to the die casting process that we will look discuss: melting, casting and trimming.
The process starts by using a gas furnace to liquefy the Zamak alloy. Once the alloy is melted, agents are added to help remove impurities in the metal. Just the burning of a gas-powered furnace produces CO2 and NOx, both of which we have looked at in terms of the harmful side effects they cause. The addition of molten metal and impurity removing agents only increase the output of harmful pollutants. According to (Watkins, Mani and Lyons), the entire melting process releases NOx, CO2, CO, and SO2 (Fig.1). These toxic gases then released into the air via tall smokestacks.
Once the metal is melted it is then ready for casting. Before the die is injected with the metal it is sprayed with a lubricant. This lubricant release volatile organic compounds (VOCs) and hazardous air pollutants when the heated by the molten metal (Watkins, Mani and Lyons). Water is then sprayed on the mold to quench the metal and solidify its form. The quenching water picks up the leftover lubricant and eventually becomes wastewater when it becomes too “dirty.”
After the car has been casted it is ready for trimming. Trimming is necessary because the molten metal sometimes leaks out the seams of the die during injection. A trim press is commonly used to remove excess metal from the cast by acting as a cookie cutter and pressing down onto the cast. Hydraulic fuel and lubricant waste that leak from the trim press are also expelled through waste water (Fig 1.)
After the cars are cast they are packaged and shipped to various retail stores across the globe where they are purchased and used by millions of consumers. I will be skipping the retail aspect in this life-cycle assessment and pick up after the cars have been used and are ready for disposal.
After multiple emails and calls to the Mattel corporation and several recycling centers it has become apparently that no one is exactly sure whether or not hot wheels can be recycled. Based on my research, I know that Zamak can be recycled so it stands to reason that the cars can just be melted down to make scrap metal ingots. However, due to the lack of knowledge to this fact it is safe to assume that hot wheels can either end up in a landfill or a recycling plant. Because of this, I will be discussing the pollution associated with both landfill disposal and recycling.
When disposing of a Hot Wheel in a landfill the car is thrown in the trash bin where a garbage truck comes to collect it and take it to a waste transfer station where it is loaded onto an 18-wheeler and shipped to the nearest landfill. Both of these vehicles are powered by diesel fuel which emit particulate matter (PM), NOx, hydrocarbons (HC), and carbon monoxide (CO) (Environmental Protection Agency) Once transferred to the landfill, its harm to the environment increases. (Vaverková and Adamcová) describe how,
Organic waste biodegradation in landfills creates green-house gas called landfill gas. Water that enters the landfill forms leachate which can carry pollutants to the surroundings. Environmental problems related to leachate include groundwater pollution and oxygen depletion and ecotoxicity in surface waters.
Essentially these garbage materials, especially the metal in the Hot Wheels car break down and seep into the ground water. This creates an effect that is similar to the pollution caused by mine tailings that we discussed earlier (metal pollution of agricultural soil and surrounding bodies of water).
If the Hot Wheels car is recycled there would still be a requirement for a diesel-powered vehicle to pick up and transport the materials to the recycling plant. Similar emissions to the garbage truck would occur. Once at the plant, the metals would be sorted and melted down to make Zamak Ingots. Melting down the car would emit the same pollutants as seen in the melting step of the die casting procedure (metal fumes, NOx, CO2, CO, and SO2)
A life cycle assessment is crucial to creating a sustainable future. We have looked at the Hot Wheels 1971 Ford Mustang Mach 1 and have uncovered the hidden impacts that it causes to the environment throughout its entire lifecycle. Hopefully this information and information like it can be used to educate consumers and initiate change.
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