Effectiveness of Liquid Agricultural By-Products and Solid Complex Chlorides for Snow and Ice Control

Agro-based products and complex chlorides/minerals (CCM) based products are increasingly employed in snow and ice control operations, either used alone or more commonly as additives for chloride-based products. Recent studies have shown that agro-based or CCM-based products have the potential to improve the overall deicing and/or anti-icing performance and reduce the corrosion and environmental risks. However, the effectiveness of such products has been limited to qualitative field observations, and their specific role in snow and ice control is poorly understood. This work consists of a systematic laboratory investigation, which focuses on the thermal properties, ice melting behavior, and corrosivity of four agro-based deicers and two CCM based deicers. First, CCM-based deicers do not exhibit significantly better ability to lower the freezing point of water when compared with NaCl, but they feature slightly better ice melting capacity at -9.4 degrees C (15 degrees F) than NaCl. Second, agro-based additives appear to significantly lower the freezing point of 23wt% NaCl brine, but do not significantly improve the ice melting capacity at -9.4 degrees C (15 degrees F) or -3.9 degrees C (25 degrees F), thus implying their role as cryoprotectants. Third, CCM and agro-based deicers do not exhibit significantly lower characteristic temperature than NaCl. A very strong positive linear relationship exists between the eutectic temperature (Te) and the characteristic temperature (Tc) of the tested liquids, indirectly confirming the validity of using differential scanning calorimetry (DSC) thermograms to assess liquid deicers. The gravimetric method reveals that CCM-based deicers exhibit slightly lower corrosivity to carbon steel than NaCl, and agro-based additives exhibit significant benefits in reducing the corrosivity of 23wt% NaCl brine. The electrochemical method reveals that although the beet-based additives do not significantly alter the corrosion potential of carbon steel, the other type of additives moved the corrosion potential to a much more positive level, implying anodic-type inhibitor at work.