AN INDUSTRIAL MINERALOGY INVESTIGATION OF VARIANTS OF RECYCLED ZINC OXIDE DERIVED FROM SPENT ALKALINE BATTERIES

Spent alkaline batteries are a major cause of heavy metal content in landfills. These heavy metals can leach into local water sources, causing drinking problems and losses in biodiversity. Therefore, it is important that batteries are recycled however there are no economically viable ways to recycle batteries. It is however possible to produce zinc oxide and cryptomelane from spent alkaline batteries using passive oxidation and other techniques. These are potentially valuable materials that may enable recycling if they can be refined. Zinc oxide from used alkaline batteries was analyzed to decipher if the substance can be used for large-scale recycling.

The goal of this project is to find a low-energy method to reuse the zincite. Passive oxidation of anodic portions of batteries produces ZnO, the intended recyclable material. Scanning electron microscopy (SEM) was used to determine crystal habit of unmodified, milled and heated zinc oxide. The unmodified sample was used as a control. The heated sample was used to replicate the intensive energy process that typically occurs with remediation of battery waste. Lastly, a milled sample was used to reduce the particle size and increase surface area. Increased surface are is thought to improve bulk properties of zinc-oxide during the process. The unmodified and heated samples are similar in size and morphology. They are elongated, prismatic, and euhedral hexagonal in shape. The milled crystals are significantly smaller in size but still show the same morphology. Energy dispersive spectroscopy (EDS) displayed that there are significant amounts of Na and Al in the sample. This work shows that it is possible that recycling of zinc oxide can be developed without intensive heating. Zinc oxide can be used for many applications in the industry. These uses include rubber, sunscreen, LED-like lighting, and lasers. Zinc oxide can also be used to catalyze organic reactions. A possible future use for ZnO is solar cell materials. The recycling of spent alkaline battery waste may be able to reduce costs of zinc oxide for its many applicable uses and provide more material for innovative experimentation.