Material Extraction of Dry Battery AA:
A typical alkaline dry AA cell comprises a cylindrical external case, cathode, anode, and electrolyte and separators. The external casing is made from nickel-plated steel and is lined with a separator to divide the anode and cathode. The separator is made of either a porous synthetic material or layered paper. On one end, the battery canister is sealed with an epoxy or asphalt sealant underlying a steel plate and at the other end with a brass rod driven through the cylinder. The rod is welded to a metallic end cap and passed via an outer plastic seal. Inside the casing is a cathode comprising a mixture of graphite, manganese dioxide, and potassium hydroxide. The anode is made from Zinc powder and potassium hydroxide as the electrolyte.
The extraction of raw materials used to manufacture dry alkaline cells has significant environmental impact. The metals such as Zinc are mined from ore deposits, and these mining activities have harmful environmental impacts such as leaving gaping quarries, air pollution by mining machinery, noise pollution, etc. Zinc and Manganese are produced from their respective ores while potassium hydroxide is chemically processed from potassium chloride, and these processes release industrial pollutant effluent if not well disposed of. The paper used in the separator is made from trees, and cutting off trees to manufacture paper harms the environment. On the other hand, steel production requires very high temperatures thus requiring more energy (usually pollutant fossil fuels are used). The steel production process also uses a lot of water, and some of this water is usually released back to the environment while untreated.
Comment:
This post on material extraction is very detailed and enlightening. It first familiarizes one with the constituent materials in an AA alkaline dry cell and then proceeds to explore how the raw materials are extracted and their impact on the environment. This makes it very easy to relate the constituent parts of a dry cell to the raw materials used to make each part.
Reference:
Advameg, Inc,. (2016). How battery is made - material, production process, manufacture, making, used, parts, components. Madehow.com. Retrieved 3 May 2016, from http://www.madehow.com/Volume-1/Battery.html
Impact of Manufacturing Process:
The manufacturing phase of alkaline AA dry cells is broken down into the production of raw materials after extraction, and this includes the acquisition by manufacturing facilities, refinement, and actual dry cell manufacturing. In some cases, the distribution process of manufactured batteries is also to be considered. The greatest inputs in this phase are electricity water and natural gas. According to Olivetti, Gregory, and Kirchain (2011), alkaline dry cells account for about 80 percent of the batteries manufactured in the United States while the worldwide individual unit production is about 10 billion units. According to the same statistics, alkaline batteries in Switzerland account for 68 percent of primary battery sales, 47 percent in the EU and 60 percent in the UK. Since battery manufacturing technology is not exotic or new, quality control during manufacturing has a significant impact on quality and lifetime of the dry cells. The ability of the battery to work well under different conditions and resist corrosion are major determinants of the battery’s overall usefulness, and impact on the environment. For example, during manufacturing, the epoxy/asphalt seals are applied significantly thinner in some areas so that if gas builds up during electrolysis the seal ruptures instead of the battery exploding. Other designs utilize a hole filled with wax such that the gas pushes against the wax instead of the battery rupturing. The overall impact of the process on the environment is mainly the electricity consumption at the manufacturing facility, and the impact of fossil fuels used to run some of the machinery. There is also the issue of excessive water consumption in various chemical processes and elimination of industrial effluent.
Comments:
I have noted a rather interesting point that the manufacturing facility does use up a lot of resources such as electrical energy and fossil fuels, all which have significant impact (negative) on the environment especially since the energy sources are non-renewable and pollutant (unless solar electricity is used). The mention of quality control in manufacturing as it relates to the overall environmental impact of the dry cells and their life cycle is also an eye opener since it is only logical that quality products will have a long life, and will pose reduced impact on the environment upon disposal and/or recycling.
References:
Olivetti, E., Gregory, J., & Kirchain, R. (2011). Life cycle impacts of alkaline batteries with a focus on end‐of‐life (1st ed., pp. 9-19). Massachusetts Institute of Technology. Retrieved from http://www.epbaeurope.net/documents/NEMA_alkalinelca2011.pdf
Uses of Dry Cells:
There are various types of alkaline batteries and these non-rechargeable alkaline batteries (most common), rechargeable alkaline, lithium ion, mercury oxide, silver oxide, manganese and zinc batteries. They usually come in button size, AAA, AA, C, D and 9 Volt capacities. AA alkaline dry cells are the most popular, have multi-purpose applications, a high-performance rate, and good shelf life. They are mostly used in households to power electronic devices such as cameras, toys, flashlights, remote controls, clocks, radios and power tools. They are very useful in devices with low power drain while quality brands can retain up to 80 percent of their power capacity for a period up to 7 years. The use stage of alkaline AA dry cells does not have a significant impact on the environmental since dry cells are single use primary batteries that are only beneficial to the consumer as long as the materials contained within the cell maintain their chemical potential. In this case, proper usage of dry cells does not give emissions unless they are disposed of poorly by either breaking through the external casing or by incinerating the cells after use. Consequently, precautions must be taken when disposing of batteries after the end of their useful life, and this may involve checking for breakage on the casing. If it is found that the external case is breached or punctured in any way, the end user should take necessary safety measures such as wearing gloves when disposing of the batteries to protect themselves from potassium hydroxide which may leak from the cell and cause chemical burns and/or irritation on the eyes or skin.
Comment:
It was interesting to learn that dry AA cells have no significant impact if used properly since they are mostly sealed and designed for single use before disposal. I have also learned that disposing of AA dry cells by burning is wrong, and so is handling leaking batteries. Given that we all handle dry cells at one time or another, this post has really helped me understand the risks involved when handling punctured and leaking dry cells.
Reference:
Bernardes, A., Espinosa, D., & Tenório, J. (2004). Recycling of batteries: a review of current processes and technologies. Journal Of Power Sources, 130(1-2), 291-298. http://dx.doi.org/10.1016/j.jpowsour.2003.12.026
Disposal and Recycling of AA Dry cells:
The disposal and recycling phase of alkaline AA dry cells pose some environmental impact which cannot be ignored. However, it is good to know that the major chemicals used in dry cell manufacturing namely Manganese and Zinc do not pose an environmental hazard, and in fact, the FDA (Food and Drug Administration) does consider these elements safe for the environment. The potential major pollutants in dry cells used to be mercury which was commonly used in alkaline AA dry cells and button cells to improve performance by aiding conductivity and reducing corrosion. In fact, in the early 1980’s, alkaline dry cells had about 5 to 7 percent mercury content. However, it was soon discovered that Mercury is toxic to the environment, and thus manufacturers began to look for new dry cell manufacturing techniques that would improve efficiency without using Mercury. The main solutions focused on improving the purity of other materials. However, even with advanced manufacturing processes, modern alkaline dry cells still contain about 0.025 percent of Mercury. However, the industry-wide rule is that dry cells should not contain any Mercury at all. However, it is still difficult to guarantee products that are safe from trace mercury content since Mercury is a naturally occurring element (NEMA, 2002).
If the batteries go through proper waste separation and recycling channels instead of ending up in landfills, then up to 90% of the battery can be recycled. The recovered metals such as manganese, zinc and potassium can be used to manufacture fertilizers while recycled paper and plastic can be used for energy production and molding new items respectively. The recovered steel can be resold back for use in manufacturing. If batteries are landfilled or burned, the heavy metals and chemicals in them such as potassium hydroxide may be released into the environment and end up polluting surface and ground water. Furthermore, incinerating these cells would pollute the air and not to mention the added risk of explosions injuring the people who work in incineration sites, landfills and recycling plants.
Comment:
Given the widespread use of dry cells, it was quite interesting to learn of the various disposal and recycling methods. The fact that dry cells are almost 100 percent recyclable is very good news since recycling reduces the overall environmental impact of the materials used to manufacture the batteries. The impacts of incineration and landfills as disposal methods are also well elaborated, and it is my hope that consumers and manufacturers do take up recycling since it is the methods with least environmental impact.
Reference:
NEMA,. (2002). Household Batteries and the Environment (1st ed., pp. 1-21). National Electrical Manufacturers Association (NEMA). Retrieved from https://www.nema.org/Policy/Environmental-Stewardship/Documents/NEMABatteryBrochure2.pdf
