Theoretical and Experimental Investigation of Mechanosynthesis of Nanoparticles by Means of Dilution with the Final Product
F. KH. URAKAEV1,2, V. S. SHEVCHENKO1 and V. V. BOLDYREV2,3
1Institute of Geology and Mineralogy, Siberian Branch of the Russian Academy of Sciences,
Pr. Akademika Koptyuga 3, Novosibirsk 630090 (Russia) E-mail: urakaev@uiggm.nsc.ru
2Novosibirsk State University, Ul. Pirogova 2, Novosibirsk 630090 (Russia)
3Institute of Solid State Chemistry and Mechanochemistry,
Siberian Branch of the Russian Academy of Sciences,
Ul. Kutateladze 18, Novosibirsk 630128 (Russia)
Pages: 321-337
Abstract
Theoretical and experimental investigation of the solid-phase mechanosynthesis of nano-sized target product on the basis of dilution of the initial powder mixture of reagents with another product of the exchange reaction was carried out. Optimal molar ratios of the mixture components providing shock-friction contacts of reagent particles and excluding aggregation of nano-sized particles of the target reaction product were calculated basing on the three-modal particle size distribution. A deduction of the kinetic equation for the mechanosynthesis of nanoparticles by means of dilution is presented. The necessary time of mechanical activation (MA) for the exchange reactions to process till completion is calculated using this equation. The obtained theoretical results agree with the available literature data and with the results of experimental investigation of the kinetics of mechanosynthesis of nano-sized target product TlCl according to the exchange reaction 2NaCl + Tl2SO4 + zNa2SO4 = (z + 1)Na2SO4 + 2TlCl for the optimal value of dilution parameter z= z1* = 11.25. A number of specific features of this reaction are established. Comparing the kinetic parameters obtained for mechanosynthesis of TlCl with those for theoretically investigated exchange reaction KBr + TlCl + zKCl = (z + 1)KCl + TlBr for z = z1* = 13.5, experimental estimation of the mass transfer coefficient was carried out for the first time and the dynamics of changes in the size of nanoparticles depending on the time of MA was established for a ball planetary mill AGO-2.
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