Introduction
Whether we like it or not, we live in a digital world that runs literally on electricity. In our homes, schools, and workplaces, electricity is a crucial source of energy to make some of our tools work to help us with our current digital lifestyle. From our cars, laptops, hearing aids, calculators, and cellular phones, all these things require that portable electricity that flows from batteries. When there are power interruptions, batteries are used to rev up commuter trains, hospital facilities, and military operations. In fact, the U.S. Environmental Protection Agency (20 December 2007) reported that “Americans use nearly 3 billion dry-cell batteries every year to power radios, toys, cellular phones, watches, laptop computers, and portable power tools”.
Thus, the usefulness of batteries in our current lifestyle is undeniably clear. However, what is critical is how we get rid of these batteries when they are no longer useful. These batteries contain harmful chemicals that, when improperly disposed of, could deleteriously affect our environment. These batteries can contain poisonous cadmium, lead, and sulfuric acid that can seep into our landfills and be released into the ocean, where they can kill sea creatures. When sea creatures have an intake of these substances, humans and other animals that consume seafood are also at risk. In this paper, we will delve into why the improper disposal of batteries can be harmful to our environment. This report will ponder on the various harmful chemicals that are used in manufacturing batteries and how they can have an enormous environmental impact. The first point is about the environmental impacts of the non-recycled used batteries and how these impacts affect people in their daily life. The second point is how effective battery recycling would reduce those impacts that are caused by used batteries. Lastly, recommendations will be made in order to convince people of the necessity of recycling batteries with lesser environmental repercussions.
Batteries From Within
The Encyclopædia Britannica Online (7 April 2008) characterized batteries as “devices that convert chemical energy directly into electrical energy.” Batteries can be of two general types: the primary battery and the secondary battery. The primary battery delivers current as of the result of a chemical reaction that is not efficiently reversible. Practically, this makes the primary battery non-rechargeable. Only one intermittent or continuous discharge can be obtained before the chemicals placed in it during manufacture are consumed. Then the discharged primary battery must be replaced.
On the other hand, the secondary or storage battery is rechargeable because it delivers current as of the result of a chemical reaction that is easily reversible. When a charging current flows through its terminals in the direction opposite to the current flow during discharge, the active materials in the secondary battery return to approximately their original charged condition. According to Tchobanoglous (2002), there are different batteries based on their “chemical composition, energy storage capacity, voltage output, and life span. These factors affect their overall performance, utility, and cost. Because of their different intended uses, consumer batteries are usually distinguished as automotive (i.e., lead-acid storage batteries) and household batteries” (p. 364). The different types and uses of batteries are described in Appendix A.
To be able to generate electricity, batteries contain two different solutions that have ions that could “chemically react to transfer electrons from one to the other.” These ions are atoms o different chemicals “that carry a charge because they have more or fewer negatively charged electrons than positively charged protons.” Instead of a direct transfer, however, the electrons leave the batteries via one electrode — the cathode – and return through another – the anode. In this process, a current of electrons is released to a device connected to the battery. The anode is generally made from a more conductive material than the cathode (Patch 2003, p. 2).
As the energy of the metal ions inside the battery can be depleted, the life expectancy of a cell or battery depends on its design and materials, as well as its application and operating conditions. Life expectancy is measured by shelf life and service life. Shelf life is the expected time that elapses before a stored battery becomes inoperative due to age or deterioration or unusable due to its own internal self-discharge. Service life is the expected length of time or number of discharge-charge cycles through which a battery remains capable of delivering a specified percentage of its capacity after it has been put into service. This can vary from the one-shot or single discharge obtainable from primary cells to 10,000 or more discharge-charge cycles obtainable from some secondary batteries. The most common automotive batteries (lead-acid) may last as little as 18 months in hot climates and 10 – 12 years in cold climates, but typically they have an average life of 3 years (Besenhard, 1999).
Since batteries become useless until their energy is depleted, the proper disposal of these items can be a problem because these contain harmful chemicals like lead, sulfuric acid, cadmium, mercury, and other harmful substances that might affect our environment.
Harmful Battery Components
Lead is a non-ferrous metal, which may be, used in soil pipes, accumulators (an alloy with antimony), as antiknock in gasoline (tetraethyl lead Pb (C2H5)4), cable sheathings, paints, and different alloys (white metal, pellets, types, etc.). Stavros et al. (2003) informed that the biggest use of lead worldwide is for the lead-acid battery. Lead is particularly suitable for batteries because of its characteristics (conductivity, resistance to corrosion, and the special reversible reaction between lead oxide and sulfuric acid). The majority of lead-acid batteries are used as SLI batteries (starting, lighting, and ignition) for the purpose of starting the engines of cars and trucks. Another sort of lead-acid battery is the traction (driving) battery, used for electric power vehicles such as milk floats, forklift trucks, and airport support vehicles. This type of battery provides the best service for ‘stop and start conditions.
The last sort of lead-acid battery concerns stationary battery, which provides uninterrupted electrical power (e.g., in hospitals, telephone exchanges, companies, etc.). The main components of a lead-acid battery and, more specifically, of an SLI battery are active mass or lead paste which includes: cathode (positive pole), which consists of metallic lead (Pb), anode (negative pole), which consists of lead oxides (PbO2), grids and connecting bridges made of suitable lead-antimony, lead-calcium (tin) (aluminum) alloys with additives, is negligible quantities, such as copper, arsenic, tin and selenium, electrolyte (liquid filling of sulfuric acid) in which lead-antimony plates are immersed, casing, usually made of polypropylene, and, less frequently, of hard rubber, ebonite, bakelite, etc. other components such as paper, rubber, fiberglass, and wood.
When lead-acid batteries are not disposed of properly, lead does not break down over time, and, in some places, large amounts of it remain in the air, soil, and water. Lead poisoning can affect fetuses and children under age seven because their nervous systems are still developing and because their body mass is so small that they ingest and absorb more lead per pound than adults. Even ten micrograms (millionths of a gram) of lead per deciliter of blood—the Centers for Disease Control and Prevention (CDC) standard for lead poisoning—can kill a child’s brain cells and cause poor concentration, reduced short-term memory, slower reaction times, and learning disabilities (Millstone 1997, p. 15). On the other hand, adults exposed to low levels of lead (which once were thought to be safe) may develop headaches, high blood pressure, irritability, tremors, and insomnia. Health effects increase with exposure to higher levels and include anemia, stomach pain, vomiting, diarrhea, and constipation. Long-term exposure can impair fertility and damage the kidneys. Workers exposed to lead may become sterile or suffer irreversible kidney disease, damage to their central nervous system, stillbirths, or miscarriages (Millstone 1997, p. 18).
On the other hand, sulfuric acid on lead-acid batteries can also be detrimental to our environment. As we all know, sulfuric acid can mix with groundwater and soil, causing these to become acidic and harmful to plants and wildlife. Commonly known as “acid rain,” sulfuric acid triggers acid deposition that “adversely affected lakes and forests in the northeastern United States, Canada, and Europe.” Due to the “gradual leaching of soil nutrients from sustained acid deposition,” forests and wildlife are even affected with “potential risk depends on numerous factors, including rate of cation (positively charged ion) deposition, soil cation reserves, age of forest, weathering rates, species composition, and disturbance history” (Lippmann, 2002).
Mercury is also used for cadmium-mercuric oxide batteries and zinc-mercuric oxide batteries. When accumulated in the environment, mercury poisoning can lead to a disease affecting the central nervous system, mucosal surfaces of the mouth, and the skin caused by environmental or occupational exposure to mercury or any of its compounds. These may be ingested, inhaled, or absorbed through the skin. Many mercury compounds bioaccumulate, for example, in Minamata Bay, Japan, where industrial effluent containing methyl mercury salts bioaccumulated in zooplankton and crustaceans and caused the condition called Minamata disease (Last, 2007). Symptoms of mercury poisoning include a racing heartbeat, sweating, aching limbs, kidney problems, hand tremors, peeling skin, and emotional problems.
Lastly, cadmium can come from nickel-cadmium batteries that are dominant alkaline secondary batteries and used in many heavy industrial applications like lead-acid batteries. At the same time, nickel-cadmium batteries are found in applications requiring portable power, such as electronics and power tools. Bender (2005) informed the hazard of ingesting cadmium because it accumulates in the body throughout life, reaching a total body content of 20-30 mg. It is toxic, and cadmium poisoning is a recognized industrial disease. In Japan, cadmium poisoning was implicated in “Itai-itai” disease, a severe and sometimes fatal loss of calcium from the bones that occurred in an area where rice was grown on land irrigated with contaminated wastewater. Accidental contamination of drinking water with cadmium salts also leads to kidney damage, and enough cadmium can leach out from cadmium-based batteries.
Recycling Batteries with Toxic Components
With the onset of concern towards the harmful components of batteries, the Universal Waste Rule, an amendment to the Resource Conservation and Recovery Act (RCRA), was initiated by the United States Environmental Protection Agency (EPA) in 1995 in order to reduce some of the “administrative and financial barriers to collection and recycling of batteries and other potentially hazardous household products.” The intention of such a program is to make “recycling of lead batteries easier and more profitable to recycle would lead to more extensive recycling programs. The rule streamlined the regulatory process for businesses and excluded rechargeable batteries from hazardous waste handling requirements. However, individual states had the final determination over whether or not to adopt the amendment” (Ford-Martin, 2003). Another development came up in 1996 when the “Mercury-Containing Rechargeable Battery Management Act (or Battery Act)” was enacted to encourage people in “recycling of rechargeable batteries through a national uniform code that removes obstacles presented by conflicting state recycling laws and regulations. The Battery Act also mandates that manufacturers of portable rechargeable batteries and products use universal recycling labeling, make batteries easy to remove from products and prohibit the intentional introduction of mercury” (Ford-Martin, 2003).
In lead-acid recycling batteries, the process is very similar to the primary lead production process. The main differences are in material preparation before reduction, which affects plant size since there is no need for sintering. The sequential recycling steps normally are the separation of the plastic case (using hammers or saws), acid removal, separation of the plastic, metallic lead and paste separation, reduction, refining, and casting. Acid, polypropylene, and lead are recovered in the recycling process Espinosa et al., 2004). The process is illustrated in Appendix B.
On the other hand, batteries containing mercury can also be effectively recycled. According to Yue-qing and Guo-jian (2004), the method entails a vacuum metallurgical reprocessing. This method can be used to reclaim the mercury (Hg) in the dry batteries and the cadmium (Cd) in the Ni-Cd batteries. The ferrite synthesis process reclaims the other heavy metals by synthesizing ferrite in a liquid phase. Mixtures of manganese oxide and carbon black are also produced in the ferrite synthesis process. The effluent from the process is recycled, thus significantly minimizing its discharge.
Also, the Eveready Battery Company developed a process that is applicable to the treatment of wastes containing cadmium (Cd). It is a pyrometallurgical process in which heating occurs in three steps and in the same furnace. The operation temperature in the first thermal cycle is in the range of 200–300 °C, and the holding time is around 1.5-2 hours. The objective of this step is the elimination of moisture in the load. The second step takes approximately 2-2.5 hours with temperatures ranging from 500 to 700 °C. The objective of this phase is the removal of organic material. Finally, the temperature goes up to 900-1100 °C, where the Cd distillation occurs. The holding time is around 2.5-3.5 h. In this step, an inert gas (argon) is purged in the reactor. Besides the inert gas, a carbonaceous material is placed at the surface of the load to react with the oxygen that might be originated in the load; consequently, this added material diminishes the oxygen potential of the chamber. Vapor is condensed in a chamber adjacent to where the temperature ranges from 400 to 300 °C. Recovered Cd has 99.9998% purity (Espinosa et al., 2004).
Recycling Batteries without Toxic Components
With the upsurge of electronic equipment like cellular phones and laptops, high-power lithium-containing batteries have been extensively used as electrochemical power sources in modern life equipment. They are often referred to as conventional systems with aqueous electrolytes such as nickel-cadmium (Ni-Cd) rechargeable batteries. In 2003, primary lithium batteries and lithium-ion secondary rechargeable batteries (LIBs) represented about 28% of the rechargeable battery world market (Lee & Rhee, 2002). There is an important difference between primary lithium batteries and lithium-ion secondary rechargeable batteries (LIBs). Primary lithium batteries use metallic lithium as cathode and contain no toxic metals. However, there is the possibility of fire if metallic lithium is exposed to moisture while the cells are corroding. Lithium-ion secondary rechargeable batteries (LIBs), on the other hand, do not contain metallic lithium. Most lithium-ion systems use a material like LiXMA2 at the positive electrode and graphite at the negative electrode. Some materials used at the cathode include LiCoO2, LiNiO2, and LiMn2O4. LIBs contain toxic and flammable electrolytes, an organic liquid with dissolved substances like LiClO4, LiBF4, and LiPF6 (Xu et al., 2008). The danger posed by lithium-containing batteries makes it also a candidate for proper recycling measures.
According to Xu et al. (2008), recycling LIBs has increasingly become important because their safe disposal may pose a serious problem due to the presence of flammable and possibly toxic elements or compounds. Although spent LIBs are not generally classified as dangerous wastes, some economic benefits could be achieved in the recovery of major components from LIBs. Unlike other batteries, LIBs often blow up during the recycling process due to the radical oxidation of lithium metal produced from battery metals. There are two problems to be solved; disposal of harmful waste and prevention of explosion during recycling of LIB wastes. Since spent LIBs represent a valuable waste material for the recovery of metals present (Co, Li, Mn, and Ni) or their compounds, recycling spent batteries may result in economic benefits. Recovery of cobalt and lithium is one of the primary objectives in the recycling of spent LIBs since cobalt is a rare and precious metal and is a relatively expensive material compared with the other constituents of LIBs, and lithium is also vitally important in many industrial applications.
Conclusion
As we have tackled above, batteries should not be disposed of indiscriminately. These things can become hazardous wastes because they may contain toxic substances that may harm our health and our environment, as well. Although there may be batteries that have no toxic substances, these should also be recycled because they can pose other threats because the chemicals can be flammable and can cause unknown problems in the future. As the world’s resources are diminished, reusing batteries is not only environment-friendly, but it can also produce primary raw materials that can be used for other things. To recycle and reuse waste to the maximum possible extent should not only be promoted in batteries but to other things as well. Reducing the quantity of unrecoverable waste and disposing of toxic wastes as safely as possible can benefit people more in a proactive way.
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