Used batteries contain a variety of heavy metals, and direct disposal not only pollutes the environment, but also wastes resources. Dealing with it, eliminating its harm to the environment and recovering valuable substances have been the goals of many domestic and foreign researchers for many years.
The main principle of the vacuum pump used in the used battery process: based on the components of the waste dry battery have different vapor pressures at the same temperature, they are separated from each other at different temperatures by evaporation and condensation in a vacuum, so as to achieve Comprehensive recycling and utilization. The whole process is divided into two steps. The first step: evaporate the volatile mercury in vacuum at about 300 ℃ and condense and recover; the second step: add calcium oxide to convert zinc chloride to zinc oxide, and reduce and oxidize in vacuum at 800 ~ 900 ℃ Zinc, the produced zinc is distilled out and condensed and recovered together with the zinc in the battery, so that the three kinds of zinc (Zn, ZnCl_2, ZnO) in the battery are recovered in the form of metallic zinc.
Rotary vane vacuum pumps are generally used in the recycling of used batteries:
1. Rotary vane vacuum pump is baked at low temperature. During the heating process of used batteries, water, wax, ammonium chloride and other substances will be continuously distilled out, and organic substances such as paper and paste will be ashed; as the temperature continues to rise, the remaining elemental zinc in the battery will begin to melt, you can Recycling.
2. Used batteries chlorinated and roasted by rotary vane vacuum pumps are roasted at a low temperature, during which moisture, organic matter, ammonium chloride, etc. are completely removed. Metal chloride has the characteristics of low melting point, good volatility, and easy dissolution in water, which is convenient for recovery and use.
This process has the advantages of high recycling efficiency, low energy consumption, low secondary pollution, and low equipment investment, which is beneficial to the treatment and recycling of used batteries in small and medium-sized cities and even towns, and has greater economic and social benefits.
Keywords: used battery recovery, rotary vane vacuum pump
Editor: Emily Fu / Shanghai EVP Vacuum Technology Co., Ltd.