With the miniaturization of electrical appliances, more and more batteries are used. Laptops, mobile phones and digital cameras all need batteries as power supply. Whether disposable or rechargeable batteries, waste batteries cannot be discarded at will. This is mainly because the battery contains some toxic and harmful substances, which will pollute the environment once discarded at will. Data show that a No. 1 battery can permanently lose the use value of 1 square meter of soil, and the polluted water can even reach an amazing 600000 liters! Therefore, waste batteries must be recycled all over the world.
Fixed point recycling of waste batteries began in the 1970s, when people began to widely use rechargeable nickel cadmium batteries. Its cathode material is cadmium, which is a very harmful metal to human body. In the 1950s, some strange patients appeared in the Toyama plain in central Japan, starting with pain in the waist, hands and feet, followed by bone pain all over the body, difficulty in movement, symptoms of bone atrophy, bending and softening, and inexplicable fractures. The patient stayed in bed day and night, kept shouting pain, and died in the cry of "pain... Pain...".
Japan calls this disease "pain disease". When dissecting the corpse, it was found that some patients had 72 fractures all over the body, and some patients' height was shortened by 30 cm. It was not until 1968 that it was found that this "pain" was caused by the discharge of cadmium containing wastewater by Mitsui metal company in Japan. The sewage discharged by the company directly pollutes rivers and farmland. Local residents drink "cadmium water" and eat "cadmium rice" every day. Over time, some people get "pain disease". Modern medicine has confirmed that this disease is a symptom of acute cadmium poisoning and named it "bone pain disease".
The destructive effect of cadmium on bone mainly comes from the similarity between cadmium and calcium. Cadmium and calcium exist in the form of divalent cations in bone, and their "size" is also very similar. When cadmium enters the body, it will gradually replace calcium, causing people to suffer from "bone pain disease".
The discovery of bone pain disease has aroused the vigilance of countries all over the world. Countries have successively formulated measures to recycle waste cadmium nickel batteries at fixed points, and recycle disposable batteries at the same time. This is because most disposable batteries use zinc as the negative electrode, such as commonly used No. 1 or No. 5 zinc manganese dry batteries and button batteries. Metallic zinc is very active and will dissolve in acidic or alkaline solutions and produce hydrogen. Therefore, when the battery is not in use, the expansion and even explosion of the battery will be caused by the generation of hydrogen.
In order to prevent this phenomenon, the zinc electrode is usually covered with a layer of mercury. Therefore, all disposable batteries with zinc as negative electrode contain mercury. Mercury vapor can cause severe tremor and tremor of muscles. Therefore, disposable batteries should not be thrown randomly, otherwise the mercury in them will also pollute the environment.
In various batteries, there are some other heavy metals and their compounds. Once converted into water-soluble substances, they will also pollute the soil and water.