What are the hazards of battery over-discharge?

Introduction to Waste Battery 1: composition of battery: The composition of dry battery and rechargeable battery: zinc skin (iron skin), carbon rod, mercury, sulfate, copper cap; battery is mainly lead compound. For example: the composition of No. 1 waste zinc-manganese battery, weighing about 70 grams, including 5.2 grams of carbon rods, 7.0 grams of zinc skin, 25 grams of manganese powder, 0.5 grams of copper cap, and other 32 grams. 2. Types of batteries: The batteries mainly include disposable batteries, secondary batteries and car batteries. Disposable batteries include button batteries, ordinary zinc-manganese batteries and alkaline batteries, and disposable batteries contain more mercury. The secondary battery mainly refers to a rechargeable battery containing heavy metal cadmium. Car waste batteries contain acid and heavy metal lead. 3. Number of batteries: DC, MP3 and other digital products are developing at a super-fast speed, and all of them are using batteries. The use of batteries is increasing rapidly. If no action is taken, the phenomenon of Battery Mountain will happen sooner or later. The waste battery looks very inconspicuous, but the damage is great. If you know the dangers of mercury, cadmium, lead and other metal substances contained in the battery, you will know that the waste battery is so powerful. Harm of used battery cells The environmental hazards of battery products are mainly the contamination of electrolyte solutions such as acids and alkalis and heavy metals. Different types of battery contaminants are also different. In general, harmful substances in batteries mainly include heavy metals such as Zn, Hg, CNA, and Pb; H2S04 in lead storage batteries; KOH in various alkaline batteries and IiPP6 electrolyte in lithium batteries. Hg and its compounds, especially organic mercury compounds, are highly biotoxic, have a faster bioaccumulation rate and have a longer biological half-life of brain organs. Cd is easily enriched in animals and plants, affecting the growth of animals and plants, and has strong toxicity. Pb has adverse effects on human chest, kidney, reproduction, cardiovascular and other organs and systems, manifested as mental decline, kidney damage, infertility and high blood pressure. The toxicity of Zn and Ni is relatively small, but when it exceeds a certain concentration range, it will have adverse effects and harm to the human body. The acid and alkali solution in the used battery will affect the pH of the soil water system and make the soil and water system acidic or alkaline, the main component of the battery electrolyte composition is the soluble heavy metal therein, especially the large amount of lead sulfate in the lead battery electrolyte and the cadmium hydroxide in the nickel-cadmium battery. The heavy metal ions in the battery are dissolved in the soil or water and absorbed by the roots of the plants. When the animals use the plants as foodstuffs, heavy metals accumulate in the body, Humans eat heavy metal foods, vegetables and meat, water, along food chain heavy metals will be enriched in the human body. Because heavy metal ions are difficult to excrete in the human body, it will eventually damage the nervous system and liver function of the human body. Waste Battery Recycling Research 2.1 Waste Battery Recycling Status The most used industrial battery in China is lead storage battery. Lead accounts for more than 50% of the total battery cost. It mainly uses fire method, hydrometallurgical process and solid phase electrolytic reduction technology. The outer casing is made of plastic and can be regenerated, basically achieving no secondary pollution. Small secondary batteries are currently used in nickel-cadmium, nickel-hydrogen and lithium-ion batteries. Cadmium in nickel-cadmium batteries is one of the heavy metal elements strictly controlled by environmental protection. Organic electrolytes in lithium-ion batteries, nickel-cadmium and nickel-hydrogen batteries the alkali in the base and the heavy metals such as copper, which are auxiliary materials for the manufacture of batteries, constitute environmental pollution. The current domestic use of small secondary batteries is only a few hundred million, and most of them are small in size. The utilization value of used batteries is low, and the use of dispersion is mostly used for domestic garbage disposal. There are cost and management aspects of recycling. The problem of recycling also has certain technical problems. Civil dry batteries are currently the most used and most dispersed battery products, with annual consumption of 8 billion. There are two major series of zinc manganese and alkaline zinc manganese, as well as a small amount of zinc silver, lithium batteries and other varieties. Zinc-manganese batteries, alkaline zinc-manganese batteries, and zinc-silver batteries generally use mercury or mercury compounds as corrosion inhibitors, and mercury and mercury compounds are highly toxic substances. When the waste battery is incinerated as domestic garbage, some of the heavy metals such as Hg, Cd, Pb, and Zn in the waste battery are exhausted at a high temperature, and some of them become ash and cause secondary pollution. 2.2 Waste dry battery recycling technology a. Manual sorting and recycling technology generally classifies dry batteries, performs simple mechanical cutting, manually separates zinc skin, plastic cover, carbon rod, etc., and the remaining mixture of Mn02 and manganite is sent back to the brick kiln for calcination. Dehydrated Mn02, this method is simple and easy, but it takes up a lot of labor and has little economic benefit. b. The fire recycling technology generally classifies and crushes dry batteries into a rotary kiln. At a high temperature of 1100~1300 degrees Celsius, zinc and zinc chloride are oxidized to zinc oxide and discharged with flue gas, and are oxidized by a cyclone. Zinc, residual manganese dioxide and manganite enter the residue, and further recover manganese and other substances. This method is simple and easy, and the general smelter can recover zinc without adding equipment. c. The wet recycling technology is based on the principle that zinc and manganese dioxide are soluble in acid. The waste dry batteries are sorted and crushed, placed in a leaching tank, and diluted with sulfuric acid (100-120 g/L) to obtain a zinc sulfate solution. The metal zinc can be obtained by electrolysis, and after the filter residue is separated by washing to separate the copper cap and the carbon rod, the residue Mn02 and the manganite are calcined to obtain Mn02. The methods used are roasting-leaching and direct leaching. Compared with the fire method, the wet method has the advantages of low investment, low cost, fast construction, high profit and flexible process, but it cannot guarantee the complete recovery of harmful components. 3 The prevention and control of secondary pollution in the recycling process of waste batteries The above three recovery methods are simple and easy, but each has its own problems, and there are secondary pollution problems. Through a large number of experimental measurements, we have obtained the feasibility of preventing secondary pollution. method. First, the waste dry batteries are classified, and after mechanically cutting, the copper caps and zinc skins are separated and can be separately recycled. After removing the iron by magnetic separation, the remaining carbonaceous material is immersed in water for 1 hour at a solid-liquid ratio of 1:4, and the supernatant liquid is taken for evaporation and crystallization. The main components of the precipitate are Mn02, MnO(OH), acetylene black. The carbon rod and other substances are added to the rotary kiln to 600 degrees Celsius, and the generated flue gas is condensed to obtain a condensed liquid, and the pure mercury can be obtained by regular cleaning. It also prevents mercury vapor from polluting the environment. During calcination, a large amount of acetylene black and carbon in the mixture reduces MnO 2 to MnO. The reaction process is as follows: 2Mn02+C--->2MnO+C02 The calcined product is added to a sulfuric acid solution having a concentration of less than 2 mol/L at a solid-liquid ratio of 1:4, and immersed at a temperature of 80 ° C for 1 hour, and the following reaction occurs: MnO+H2S04--->MnS04+H20 gives a manganese sulfate solution, and at the same time, other soluble heavy metal sulfates will also be introduced. The obtained zinc skin and copper and other metals can be directly remelted. Ammonium chloride can be used as a chemical reagent for fertilizer or purification. Manganese sulfate is a hormone component for animal and plant growth, and can be used as a drying agent for paint inks and some organic synthesis reactions. The catalyst is also used in the production of paper, ceramic, printing and electrolytic manganese. Table 1 shows the composition of the recoverable substances of the zinc-manganese dry battery. This recycling method has less investment, and the equipment used is simple and easy to implement in small and medium-sized cities, thus eliminating the problem of transportation of used batteries. The solution after the waste battery is recovered, concentrated and reacted with EDTA to form a metal complex, which can completely eliminate secondary pollution. It has been determined that the amount of heavy metals contained in the solution after recycling the waste battery complies with national environmental protection standards. To separate these metals, they can be graded with different stability. Table 2 shows the stability constant of complexation of metal ions with EDTA. 4 problems in the recycling process of used batteries and recommendations 1 battery cannot be disposed of after recycling, generally stacked. During the stacking process, the battery may leak or toxic substances may spread. 2 Due to the wide variety of batteries and the number of counterfeit products, it also brings difficulties to battery recycling. Some batteries are mercury-containing batteries, some are cadmium-containing batteries, some use ammonium chloride as electrolyte, and some use chlorination. Zinc is an electrolyte, so it is recommended that manufacturers use a uniform standard to identify the type of battery and the main components contained in it for recycling. 3 Strengthen the development of high-performance environmentally friendly batteries to achieve mercury-free general-purpose batteries. 4 The recycling and disposal of waste batteries, the state should give support from the policy references 1 Blue Country. Several comprehensive utilization methods of waste dry batteries [J], environmental Science Dynamics 2000 (4). 2 Niu Dongjie, Nie Yongfeng. Analysis of China's waste battery management countermeasures [J], Urban Environment and Urban Ecology, 2000, 13 (1) 3 Yang Jialing, Recovering heavy metals from industrial waste [J], Chemical environmental protection, 1997, 174 Xia Yueqing, et al. Comprehensive recycling method for mercury-containing waste batteries [P], CN00127859,20025 Zhang Shengtao, et al, the harm of waste battery and its recycling [J]. The battery industry, 2002, 7 (1) from the "China Resources Comprehensive Utilization" magazine from the beginning, care for the environment, love yourself, participate in the recycling of used batteries is the responsibility and obligation of each of our caring people. Will our "Chinese dolls" do better in protecting their homes, protecting the environment, and protecting their own actions?

This should be considered a harmful job.

The battery is divided into two categories: battery and dry battery. The battery has lead-acid batteries, nickel-cadmium batteries, nickel-hydrogen batteries and lithium batteries; dry batteries include zinc-manganese batteries, magnesium-manganese batteries, and alkaline batteries. More widely used are lead-acid batteries, lithium batteries and zinc-manganese batteries. In the battery production process, different occupational hazards may be generated depending on the raw materials and production processes used.

Heavy metal hazards: Lead-acid battery production, lead powder manufacturing, grid manufacturing, and paste, coating, splitting, brushing, cladding, welding, shelling, soldering terminals, etc. will produce lead dust, Lead smoke. In the production of zinc-manganese dry batteries, zinc-cylinder welding will produce lead dust, and processes such as transportation, mixing, electric core and wrapping paper winding can produce manganese dust. In the production of nickel-cadmium batteries, cadmium dust and nickel dust are generated in the batching, feeding, stirring, drawing, coating, dividing, winding and other positions. In the production of nickel-hydrogen batteries, nickel, cobalt dust will be produced in the fields of powdering, sizing, tableting, slicing, tableting and winding.

Graphite dust hazard: graphite dust will be produced in the process of compounding, coating and film production in lithium battery production.

Chemical Toxic Hazards: In the production of lead-acid batteries, rubber, silk screen and other positions will be exposed to organic solvents such as benzene, toluene, xylene, acetone, methyl ethyl ketone and ethyl acetate. In the production of lithium batteries, hydrogen injection can be generated in the injection position, and the ketones will be contacted in the rolling and scrubbing positions. In the production process of nickel-hydrogen battery, there are sodium hydroxide and potassium hydroxide in the process of liquid injection, and the chemical poisons such as toluene, xylene and ethanol are exposed to the processes such as glue and silk screen printing. In the production of lead-acid batteries, acid mist is generated in the positions of sulfuric acid storage, acid distribution, acid addition, and charge formation.

Noise hazard: terminal manufacturing, grid manufacturing, closing, splitting, brushing, cleaning, stripping, etc. in the production of lead-acid batteries, stirring and splitting in the production of nickel-cadmium batteries, slicing in the manufacture of nickel-hydrogen batteries, Noise is generated by processes such as car pits, bumping, and combination bumping.

High temperature hazard: high temperature operation exists in jobs such as lead dissolving, cast plate, lead manufacturing, and soldering terminals.

Impact on human health

The battery will be exposed to a variety of heavy metals such as lead, nickel, cadmium, cobalt and so on. These heavy metals and their compounds can invade the human body from the respiratory tract, skin, and digestive tract, and can cause toxic encephalopathy, toxic nephropathy and anemia, bronchitis, chemical pneumonia, chronic respiratory tract inflammation, respiratory cancer, "cobalt cardiomyopathy", allergic dermatitis and other symptoms. Serious heavy metal poisoning can lead to toxic encephalopathy, perforation of nasal septum, renal insufficiency and so on.

In the production of batteries, a variety of dusts are exposed. Among them, carbon black dust mainly causes harm to the human body through the respiratory tract and skin, long-term inhalation of carbon black in the human body, fibrotic lesions in the lungs, causing the lung tissue to gradually harden, resulting in carbon black pneumoconiosis. When the particle size of carbon black dust is 0.5 to 5 μm, it is the most harmful to the human body, and it is irritating to the skin when it is seriously polluted.

A variety of chemical poisons are exposed to battery production. Benzene and benzene are mainly invaded by the respiratory tract and skin, which can cause acute poisoning, chronic benzene poisoning, and even aplastic anemia or leukemia. Toluene and homologues can invade the human body through the respiratory tract, skin, and digestive tract, which can cause acute and chronic poisoning.

In addition, high-frequency, noise and other physical factors can occur in battery manufacturing. For example, high temperature can cause high temperature heatstroke and damage to the cardiovascular system. Noise can cause hearing damage. In severe cases, it can cause noise and can damage the cardiovascular system, system, nervous system, reproductive system.

Preventive control measures

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