253— The Impact of Physical and Chemical Weathering on Iron slag from Standish, NY

From 1883 to 1907, magnetite ore was smelted Standish, NY. During this time, a large amount of slag, a byproduct of smelting, was created. The slag is now in a pile that covers ~13 acres in the northeastern region of the Adirondacks. The impact of weathering is evident through a comparison of samples collected ~15 years ago to partner samples still out in the field which are more fractured and have calcitic weathering rinds. For more quantitative data, we carried out a field experiment and a leaching test. In the field experiment we exposed different slag samples (glassy, chalky, and massive) to rain and monitored the changes in mass over an 8 week period. All samples lost mass however, the greatest loss came from the glassy sample (1.3% lost). We carried out a simple acid leaching test using 2M nitric acid on four samples. Bulk chemistry of pre and post test samples was determined by XRF. The chemistry of slag from Standish is dominated by SiO2, CaO, and Fe2O3(t). A highly vesicular slag showed the largest changes and all the other samples lost mass and showed changes in major elements as well as in Ba, Sr, and Zr.