Thermal conductivity improvement of liquid Nitrate and Carbonate salts doped with MgO particles

MgO possesses higher thermal conductivity which may be used as an additive in molten salts improving the heat transfer performance of molten salts. In this paper, MgO doped with two kinds molten salts named MgO-Solar Salt and MgO-LNK carbonate were prepared by adding MgO particles into Solar Salt (KNO3-NaNO3) and ternary eutectic molten carbonate (Na2CO3-Li2CO3-K2CO3) through static melting method. The thermal properties of the composite molten salts liquid such as thermal diffusivity, specific heat capacity and density were measured by LFA, DSC and MT-ZRIG-12 techniques. The particle size of MgO was measured by Zeta potential analyzer, and the dispersion of MgO in molten salts was observed in quartz crucible. The results shown that, thermal diffusivity of nitrate salt and carbonate salt are significantly enhanced with the addition of MgO particles. The particle size of MgO added in molten salts is about 1μm~2μm, which help the particles well dispersing in molten salts and forming stable solid-fluid flow.