The paper presents the results of basic research on the influence of the properties of sand grains on electrical properties of water glass moulding sands. It shows electrical properties of the main component – sand grains, crucial to the kinetics of moulding sands heating, such as permittivity εr and loss factor tgδ. Measurements were carried out with the use of the perturbation method for silica, chromite and olivine sands of different mineral, chemical composition and particle size distribution, as well as for moulding sands with water glass grade 145. Analysis of the results of measurements of electrical properties shows that all moulding sands are characterized by a similar permittivity εr and loss factor tgδ. It was found that the electrical properties and the quantity and quality of other components may have a decisive influence on the effectiveness and efficiency of the microwave heating of moulding sands with sand grains. In determining the ability to efficiently absorb the microwave radiation for mixtures which moulding sands are, the impact of all components influencing their individual technological parameters should be taken into account.
 Stachowicz, M., Granat, K. & Nowak, D. (2011). Application of microwaves for innovative hardening of environment-friendly water-glass moulding sands used in manufacture of cast-steel castings. Archives of Civil and Mechanical Engineering. 11(1), 209-219. DOI: 10.1016/S1644-9665(12)60184-8.
 Grabowska, B. & Holtzer, M. (2007). Application of microwave radiation for crosslinking of sodium polyacrylate/silica gel system used as a binder in foundry sands. Polimery. 52(11/12), 841-847. ISSN: (0032-2725). (in Polish).
 Wang, J., Zitian, F., Xiaolei, Z. & Di, P. (2009). Properies of sodium silicate bonded sand hardened by microwave heating. China Foundry. 6(3), 191-196. ISSN 1672-6421.
 Ashby, M., Shercliff, D. & Cebon, H. (2011). Materials Engineering. vol. 2. Łódź: Publishing House Galaktyka Sp. z o. o. (in Polish).
 Mujumdar, S.A. (Ed.) (1995). Handbook of Industrial Drying. New York: Marcel Decker.
 Kowalski, S.J., Rajewska, K., Rybicki, A. (2005). Physical basics of microwave drying. Poznań: Editorial Office of Poznan University of Technology. (in Polish).
 Lewandowski, L. (1997). Materials for molds. Kraków: Akapit. (in Polish).
 Granat, K., Opyd, B., Stachowicz, M., Nowak, D. & Jaworski, G. (2013). Usefulness of foundry tooling materials in microwave heating process. Archives of Metallurgy and Materials. 58(3), 919-922. DOI: 10.2478/amm-2013-0101.