Use of Calorimetry to Measure Ice-Melting Capacity

Abstract

The ability to melt snow and ice is an important feature of any deicing chemical or product. This ability is called the “melting capacity” and is defined as the grams of melted ice per gram of deicer. A product’s melting capacity determines its applicability for use in snow and ice control. The standard procedures in the United States for measuring melting capacity are SHRP H-205.1 for solid chemicals and H-205.2 for liquid chemicals. However, these test methods have proved to be inadequately accurate for research purposes. There is a growing need to develop improved procedures as more deicing products are released on the market. This paper describes how calorimetry, which measures the heat changes that occur during a process, may be used to measure melting capacity. A calorimeter was custom made for the research described in this paper. The calorimeter required minimal mechanical handling and had high-precision temperature control that excluded the most extreme causes of measurement errors in previously developed test methods. Liquid sodium chloride was tested and compared with the calculated melting capacity. The calorimeter produced accurate results. Tests were also performed on magnesium chloride; the results demonstrated that magnesium chloride had a higher melting capacity than sodium chloride.