DEVELOPMENT OF RATIONAL METHOD OF SYNTHESIS OF NANOCRYSTALLINE LEAD MOLYBDATE IN MELTS OF Na2MO2O7 - PbCO3 SYSTEM

Abstract

The work presents material on interaction of dimolybdate of sodium and carbonate of lead, and also data on the development of a rational method for the synthesis of PbMoO4 in the melts, characterized by high productivity and yield of the target product of "h.с." brand in the nanocrystalline state. To achieve the work aims the thermodynamic assessment of the ability of the synthesis of molybdate of lead in melts of the system Na2Mo2O7 – PbCO3 was given. It is shown that the thermodynamic probability of formation of molybdate of lead in a number of Na2Mo2O7 – PbO(PbO2, PbCO3), is maximal for the process in the system of dimolybdate sodium – lead carbonate. The starting material for the synthesis of lead molybdate – dimolybdate sodium – was synthesized from recrystallized and dehydrated sodium molybdate and molybdenum oxide (VI). The melting temperature of synthesized dimolybdate sodium is 612 °C (614 °C – literature data). Synthesis of lead molybdate was done after careful grinding of the initial reagents and sifting through a sieve. The temperature of the synthesis process of 650 °C was maintained for 1.5 h until reaching the constant weight of mixture. Then mixture was sintered, cooled to room temperature and leached with hot (70-80 °C) distilled water. The precipitate of lead molybdate was filtered, washed on the filter to a negative reaction on molybdate ion. Synthesized molybdate of lead was dried, washed and calcined to constant weight. The yield of lead (II) molybdate was of 99.88% of the theoretical. Analysis of the obtained product was based on reaction between PbMoO4 with sodium carbonate with the formation of sodium molybdate, lead oxide (II) and carbon oxide (IV). Thus obtained sample was sintered, leached with hot distilled water and filtered. The residue was treated with acetic acid obtained from acetate of lead, the latter is determined in a form of lead molybdate (sodium molybdate deposition). To determine molybdenum from the filtrate from PbO, the inverse sedimentation method was used, in the form of BaMoO4, which is its weight form. The work also contains a material on the identification of the synthesized product by modern research methods.For citation:Shurdumov G.K., Cherkesov Z.A., Kandurova E.F. Development of rational method of synthesis of nanocrystalline lead molybdate in melts of Na2Mo2O7 – PbCO3 system. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2017. V. 60. N 7. P. 78-84.