Investigation of accumulation of impurities in lead and magnesium oxides by the neutron activation analysis while grinding them in jasper mills

The presence and buildup of impurities in raw materials of segneto-ceramics (PbO and MgO) while grinding them in jasper mills have been investigated. By the long-lived isotopes in PbO the following impurities are identified: La, Au, Sc, Sb, Co, Se, Cr, Na, Fe, Hg; in MgO - La, Au, Sc, Se, Cr, Hf, and Na. The increase of the concentration of La, Au, and Sc in PbO and MgO is found to be dependent on the grinding time. It is discovered that La concentration grows to nx10-6 g/g and Au and Sc - to nx10-8 g/g during 50 hours of grinding time