Experimental determination of single-crystal halite thermal conductivity, diffusivity and specific heat from −75 °C to 300 °C

Abstract

The thermal properties of halite have broad practical importance, from design and long-term modeling of nuclear waste repositories to analysis and performance assessment of underground natural gas, petroleum and air storage facilities. Using a computer-controlled transient plane source method, single-crystal halite thermal conductivity, thermal diffusivity and specific heat were measured from -75°C to 300°C. These measurements reproduce historical high-temperature experiments and extend the lower temperature extreme into cryogenic conditions. Measurements were taken in 25-degree increments from -75°C to 300°C. Over this temperature range, thermal conductivity decreases by a factor of 3.7, from 9.975 to 2.699 W/mK , and thermal diffusivity decreases by a factor of 3.6, from 5.032 to 1.396 mm²/s. Specific heat does not appear to be temperature dependent, remaining near 2.0 MJ/m³K at all temperatures. This work is intended to develop and expand the existing dataset of halite thermal properties, which are of particular value in defining the parameters of salt storage thermophysical models. The work was motivated by a need for thermal conductivity values in a mixture theory model used to determine bulk thermal conductivity of reconsolidating crushed salt.