Lead acid batteries are commonly used in the automobiles. The Environmental Protection Administration (EPA) has estimated that over 50,000 tonnes of lead acid battery waste were produced in recent years. But recycling process of lead-acid batteries causes a lot of interest in the issues of the environmental protection. In Taiwan, all of waste lead-acid battery treatment plants use pyrometallurgical technique. But it will produce two type of byproducts which have high lead content by the treatment method. One type of the byproducts is slag, and the other type is fly ash. Unfortunately, these byproducts are treated as hazardous industrial waste now. Not only increases the cost of treatment, but also waste the lead which contained in those byproducts. In order to improve the above problems, hydrometallurgical technique which includes two steps of leaching in alkaline solutions and electrolysis was tried to use in this study. For one thing, it can reduce the quantities of these hazardous industrial waste. Besides, it also can recycle the lead from these byproducts. Up to now the weight removal ratios of fly ash which was taken from three of the waste lead-acid battery treatment plants are more than 85 % in this study. The good result represents fly ash can be treated effectively by leaching in alkaline solutions and electrolysis. But slags have yet to find the suitable operation condition for treatment. If it can treat 10 tonnes fly ash per month by the method of this study, the cost can not only save 108,000 NT dollars for treatment costs, but also receive 353,600 NT dollars by selling recycled lead. After deducting operation cost, the payback period of investment just about 1 year. Therefore, this hydrometallurgical technique has considerable potential for development.

lead-acid batteries, leaching, fly ash, slag, electrolysis, lead paste