Five com. SiO2 powders were studied for grain and pore size distribution, sp. surface and adsorption-desorption isotherms and then pelletized with molten LiCl-KCl electrolyte (SiO2 content 9-15% by mass) at 600 degrees C and 25.54 MPa. The pellets (diam. 23 mm and thickness 0.9 mm) were tested for breaking power, deformation under pressure and electrolyte leakage. The SiO2 powders with low sp. surface were not suitable as pellet binder. The mech. strength of the pellets decreased with the increasing content of SiO2.