Treatment of Spent Primary Dry Cells

Based on this notice, the member companies of the Battery Association of Japan (formerly Dry Cells Association of Japan) made efforts to eliminate mercury in dry cells. As a result, the use of mercury was harmed in April 1991 for manganese cells and in January 1992 for alkaline cells. Furthermore, the production of mercury cells was stopped at the end of 1995, replacing them with zinc-air cells. 

Moreover, in order to objectively evaluate the state of dry cells when landfrlled as noncombustible garbage, the member companies of the Battery Association of Japan, entrusted the study of landfilled dry cells in 1985 to Fukuoka University. Based on the findings obtained over a 10-year observation, it was confirmed that heavy metals including mercury from dry cells did not seep or spill into water tanks, according to environmental standards. 

With regard to cylindrical manganese and alkaline dry cells, which account for some 98% (on a weight basis) of all primary cells sold in Japan, no mercury has been used in the production since 1992. Furthermore, as the production of mercury cells was stopped at the end of 1995, the amount of mercury contained in the dry cells sold in Japan was equal to 1.4 tons in 1997, i.e. only 3% with respect to the 1985 s total (45 tons). In addition, as button type cells (alkaline, silver oxide and zinc-air cells) still contain a small amount of mercury, BAJ will continue to reduce it and promote the collection and recycling of spent dry cells. 

approximately 10,000 tons of cells are collected from municipalities nationwide every year and recycled for mercury, scrap-iron and soft ferrite (magnetic material). 

In view of an efficient utilization of natural resources, recycling of the main materials used in dry cells is required, but other resources such as fuel, electricity, chemicals, etc. have to be consumed for this purpose. Therefore, a method of recycling while minimizing consumption of resources should be established. The usage of zinc and manganese which are the main materials of dry cells was approximately 20,000 tons for zinc and 30,000 tons for manganese in 1996. Each of them accounts for no more than 3% of Japan s total demand as shown in Tablel.2. 

---