ENVIRONMENTAL MINERALOGY AND GEOCHEMISTRY OF SOME SPENT ALKALINE BATTERIES FROM A REPRESENTATIVE WASTE STREAM, BUTLER COUNTY, OHIO: IMPLICATIONS FOR LANDFILL LEACHATE

Landfills are complex systems involving numerous waste materials interacting with geologic media and often in a specific geologic setting. Aqueous heavy metals are one of the numerous contaminants in landfill leachate which are either contained or released into the environment. The role battery materials play in the evolution of heavy metal concentration and valence state in landfills is poorly understood. Battery materials may release several metals into leachate. Here we present the first industrial mineralogical investigations of disposable alkaline batteries for the purpose of evaluating potential contribution and effects on landfill leachate.

Powder X-ray diffraction indicates a variety of phases are present in spent cathodic material including hetaerolite, poorly crystalline manganese oxide material, and the epsilon-manganese dioxide Akhtenskite. Zinc powder anodic material will oxidize to zincite. These Mn-oxides and zincite are recognized as catalysts and may not only contribute to leachate composition by dissolution but also likely influence organic molecule composition and valence state of heavy metals in ambient leachate.

Electron microscopy indicated particles are commonly between 2 micrometers and 200 nanometers, have a wide range of morphologies and can be easily transported by fluid or atmospheric flow in landfill settings.

Heavy metal concentrations in 50 representative disposable spent alkaline batteries were determined using inductively coupled plasma – mass spectroscopy (ICP-MS). Concentrations of metals were highly variable and have the following ranges: As (1.2 - 41.4 ppm), Ba (b.d. - 7722.2 ppm), Cd (b.d.-85.2 ppm ), Co (b.d. -142.0 ppm), Cr (b.d.-16.3 ppm), Hg (b.d.-31.5 ppm), Ni (0.4-152.2 ppm), Pb (b.d.-739.5 ppm), Sb (b.d.-1.3 ppm ), Se (b.d.-3.6 ppm) Sr (0.6-196.4 ppm), Tl (b.d.-1.1 ppm), V (b.d. – 43.9 ppm,).

These results suggest multiple sources of raw materials for these batteries and some batteries are clearly of more environmental concern than others. Mineralogical investigations of the stability and catalytic activity of spent alkaline batteries in landfill wastes warrants further investigation.