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The effect of dispersivity on thermodynamic and kinetic parameters of chemical reactions in nanodispersed systems is theoretically investigated. On the basis of the established theoretical dependences the new method of determination of surface thermodynamic properties of nanoparticles (surface enthalpy, surface entropy and surface energy) by thermal analysis (DTA or DSC) was developed. Three examples of calculation of surface properties of nanoparticles were presented to prove the feasibility of this method.

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Perlites from large-scale deposits in the USER were investigated by a modified DTG method. The technique permits an essentially higher DTG curve resolution in comparison with that of conventional DTG curves obtained with a derivatograph. The investigated perlites are classified into two groups: dense and porous. Elimination of water from perlites occurs in from 3 to 5 stages. The content of water lost at low temperature is higher in the dense perlites than in the porous ones.In the past two decades, perlites have found diverse industrial applications. The term "perlite" generally denotes an acid volcanic rock which undergoes expansion at 1000--1150 ~ a highly porous pumiceous product being obtained. The ability of perlites to expand is their most important technological property, which warrants studies of perlite behaviour at elevated temperatures. This property of perlites is governed by various factors, such as the rock formation conditions, the volcanic glass structure, the content of impurities in the material and, above all, the content of water and hydroxyl groups and the conditions of perlite thermal treatment. The data concerning the content of water in perlites are generally obtained by chemical analysis, but this analytical technique provides information on the overall water content only, without differentiating between the molecular water and hydroxyls, let alone between various molecular water types. IR and NMR spectroscopic studies yield information on the types of HOH groups, but permit only approximate evaluations of the amount of each water type present [1,2].In this context, thermal analysis is of great promise, insofar as, a part from revealing separate stages of perlite dehydration which are likely to be somehow associated with various H20 types, this method allows determination of the quantity of water evolved during each stage.So far only a limited number of thermal analyses of perlites have been reported [3], probably due to the fact that the thermal curves of perlites are of relatively little values because of the poor resolution with conventional equipment; this can be attributed to the closeness of the kinetic characteristics inherent in the separate stages of perlite dehydration. In order to obtain reliable data on perlit dehydration, it is essential to employ either a high-resolution instrument or a conventional instrument

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The thermal decompositions of dicitratoborates MI[B(CtHtO7),].nH20 (n=0-2, M' = Rb, K, Li, Nit,,) and MUlB(CtHtO7)z]z .8H20 (M II = Co, Ni, Mn, Cu, Zn, Cd) were investigated by means of TG, DTA and DTG methods. It was found that these thermal decompositions involve three successive stages: dehydration, the endothermal decomposition of the ligand, and oxidation of the residual ~ganic component. The volatile products of decomposition in each stage were detected by means of gas chromatography. The method of TGcurve transformation into the curve dm/d Tvs. m, where m is the loss of weight at each moment of time, was used for a more detailed study of dehydration. The optimal conditions for TG-curve modification were found.The dicitratoborates M~[B(C6H6OT)z].nH20, where n = 0-2, and M ~ = Li, K, NH4, Rb, and Mn[B(C6H6OT)212 9 8H20, where M n = Zn, Cd, Co, Mn, Cu were synthesized earlier [1][2][3]. The complex anion was found to be:

The theory of ore bearing weathering mantles (WM) was developed at the Institute of Geological Sciences, USSR Academy of Sciences (currently the Institute of Geology of Ore Deposits, Petrography, Mineralogy, and Geochemistry, Russian Academy of Sciences) in the 1930s. I.I. Ginzburg was an originator of this theory. The extensive new data on the bauxite , Ni , Au , REE bearing and other rare metal WM has led to the development of a general theory of exogenic ore deposits, which has been confirmed by forecasting, prospecting, and exploration of solid mineral resources. On considering the current status of the WM theory based on the results of precision research methods (XRD, IRS, EPR spectroscopy, DTA, electron micros copy, etc.), the main aspects determining its advance can be pointed out: (1) physicochemical simulation of WM formation; (2) identification and study of nanominerals in WM; (3) study of the contribution of organic matter to weathering; and (4) use of WM as indicators of climatic change in the Earth's history. As is presently established, WM are natural chemical reactors of nanoparticles of various minerals. The progress in nanom ineralogy of WM will facilitate the choice of rational methods of mining and recovery of valuable compo nents. As has been proved by electron microscopy, fossilized microbial communities, biofilms, and cyanobac terial mats occur in almost all WM. The importance of studying mutual relations of inorganic and organic substances of WM in more detail is evident. Development of the idea of using WM as indicators of paleocli mate will provide insights into global changes in the environment and complement the results obtained by traditional paleoclimatic methods. This aspect is especially topical in connection with widely discussed prob lem of global climatic warming.

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