Recycling alkaline batteries for micronutrients
A recent report commissioned by battery stewardship organisation Call2Recycle investigated the resource efficiency, health and environmental impacts of alkaline battery recycling technologies that aim to produce micronutrients. There are two companies that undertake this process in North America.
Micronutrients derived from the ‘black mass’ fraction of a battery (potassium, zinc and manganese), are used as a fertiliser in agricultural production. One of the concerns about this end market has been the potential presence of mercury (Hg), particularly in button cells, older alkaline batteries and some batteries imported from Asia. There has also been a concern that batteries containing lead(Pb) and cadmium(Cd) could end up in the alkaline battery stream due to poor sorting practices, and these heavy metals could also contaminate the micronutrient product. Recyclers have strict sorting processes in place to keep Pb and Cd out of their source material.
The study concluded that:
• the overall recycling efficiency of alkaline battery recycling processes that generate micronutrients (i.e. the proportion of materials recovered from each battery) is around 90%
• because the concentration of Cd, Hg and Pb in the black mass is minimal, their impacts on the environment and human health are negligible.