Harm and recycling of chemical batteries
Abstract: The chemical battery is closely related to our life. This paper mainly explains the principle, structure and harm to nature of different chemical batteries and how we recycle them. Its variety and characteristics vary.
Keywords: Common battery environmental hazard recycling treatment
CLC number: X705 Document code: A Article ID: 1003-9082(2017)02-0266-01
I. Common chemical battery\u003cbr \u003e 1. Zinc-manganese dry battery
Zinc-manganese battery, also known as carbon-zinc battery, contains a large amount of carbonaceous material, which belongs to the category of primary battery in chemical power supply, which is a disposable battery that can be seen everywhere around us. It is the most widely used. For the construction of the battery, the positive electrode is a carbon rod and the negative electrode is a barrel wrapped with zinc. The dry battery voltage is generally 1.5V. The dry skin of the dry battery is continuously corroded during use, so there will be a situation of gas rise or leakage during the process, and then the voltage will gradually decrease, so that it cannot be recharged to restore it, so its life is short. At the same time, the battery is relatively simple in construction, so the capacitance is relatively small.
2. Nickel-cadmium battery
The active material on the cathode material is mainly composed of nickel. Graphite does not participate in chemical reaction, which mainly enhances the conductivity of the solution. The active material on the negative electrode is mainly composed of cadmium oxide powder, and iron oxide powder is also added. The main function of the iron oxide powder is to make the oxidized cadmium powder have a strong diffusion ability and prevent the formation of a large amount of agglomeration. At the same time, the capacity between the plates can be increased. The active material is usually stored in some perforated steel strips, which are formed by pressurization, and finally the cathode material we see. Common positive and negative plates are separated by a corrosion-resistant hard rubber insulating rod. The electrolyte uses a potassium hydroxide solution with a density of about 1.40, and usually a small amount of lithium hydroxide solution is injected to extend the life of the battery and increase the amount of electricity stored in the battery.
According to preliminary investigation and statistics, nickel-cadmium batteries can be charged and discharged about 600 times, and can be quickly charged. It is several times the service life of general lead-acid batteries. It has large storage capacity and small internal resistance. It can be used by equipment with large power demand. Because the completely sealed frame structure is adopted, it is difficult to have electrolyte leakage, and it is more convenient that no additional electrolyte is needed; the nickel-cadmium battery can be repeatedly charged and discharged, and the operation is convenient and simple; but the nickel-cadmium battery has strong Memory function, also known as memory effect, so we must be able to charge when it is completely out of power, otherwise it will reduce the service life. Nickel-cadmium batteries are inseparable from our lives. Like the electric cars we use, the batteries are mainly nickel-cadmium batteries.
3. Lithium-ion battery
The earliest use of lithium-ion battery is in the pacemaker. Later, with the development of technology, the people's living standards have improved, and the miniaturized equipment has gradually entered thousands of households. Volkswagen has also put forward new requirements for power supply. Lithium-ion batteries have the advantages of large capacity, light weight, portability, and no memory effect. They are popular among more and more people and are widely used in our lives. Although the price is relatively expensive compared to the average battery, the price of lithium-ion batteries is relatively high, but the energy density is high and light. Many digital devices currently use lithium-ion batteries as the preferred material. Since lithium-ion batteries do not contain so-called heavy metals, the degree of environmental pollution is greatly reduced compared to half of the batteries.
Second, the harm of used batteries to our living environment
Waste batteries contain a lot of heavy metals such as mercury, cadmium, lead, zinc and other materials discarded in the natural environment, under the external corrosion, mercury will slowly from the battery It overflows itself, infiltrates into the soil, and finally enters our body through crops, which seriously damages the kidneys and other organs, and also damages our central nervous system. As we know, Japan's mink disease was caused by methylmercury. At the same time, the intrusion of cadmium can cause osteoporosis, rickets, and deformation of human bones. At the same time, the waste battery of the surrounding locomotive contains a lot of acid and heavy metal lead, and its loss will inevitably cause damage to the soil and water quality of our survival, which seriously affects our living conditions. Some people have described the lethality of used batteries. A waste battery is equivalent to a bomb. Although it is somewhat exaggerated, it is conceivable that the impact of used batteries on our living environment is enormous.
Third, the recycling of waste batteries
At present, the recycling technology of used batteries mainly have two metallurgical treatment methods: wet and dry.
The wet method is based on the principle that manganese dioxide and zinc are soluble in acidic solution, so that it forms a soluble salt and enters the solution, and the electrolytic solution produces manganese dioxide and zinc. The method has direct leaching method and roasting leaching method. Currently, most countries adopt wet processing methods, among which are Western countries such as the Netherlands, Austria and Germany.
The dry method is to redeem and convert certain substances in the battery at a high temperature to cause a chemical reaction. At present, there are two main dry methods, namely vacuum metallurgy and atmospheric metallurgy. Currently, the United States and Japan use this technology to dispose of used batteries.
Centralized treatment, classified landfill, such methods should use a well-sealed landfill, and require the landfill to comply with relevant safety standards to prevent leakage, so that the rate of toxic substances in the battery penetrates into the soil. It will be very slow and will not cause too much pollution to the environment in a short time. However, the landfill method does not control the pollution of used batteries from the source, but only to some extent and within a certain period of time limit the excessive damage of the battery to the environmental soil, so landfill can only play a slowing role.
Establishing a waste battery treatment plant, the resources of the division are fully and effectively utilized. The heavy metal in the used battery is lost to the soil, which will cause pollution, but it is a valuable secondary resource for rational use. The construction of waste battery factory can realize the resource, harmless and industrialization of waste battery treatment, and truly achieve circular development, which will produce good economic, environmental and social effects.
In life, we should pay attention to the classification and recycling, strive to improve our self-cultivation and social responsibility, respond to the call of the national government, support the trade-in, and promote the recycling of used batteries. At the same time, we must strengthen the publicity activities so that more consumers have It is the importance of protecting the natural environment, establishing awareness of environmental protection, and becoming a qualified citizen with thoughts, culture and strong sense of social responsibility.
Patrick Heyer. Advanced Lithium-Ion Battery System Charging Management and Protection [J].China Electronics Business·Basic Electronics, 2011,10(08):43-46.
[ 2]Ma Yunmei.Discussion on the harm and recycling of chemical battery[J].Shaanxi Education: Higher Education Edition,2011,11(Z1):101-102.