Currently, the global issue for countries is the search for raw materials and the production of bioenergy within their country; bioenergy also includes biodiesel fuels. One of the most promising biodiesel fuels is the green diesel fuel produced by the hydrogenation of vegetable oils. Three methods have been proposed to obtain high-quality biodiesel and environmentally friendly diesel fuel: compounding green diesel with hydro-treated diesel fuel, compositions of the improved fuel «green diesel» with bio-additives, and two-component mixtures of environmentally friendly diesel fuel with bio-additives. Using these methods, it is possible to produce fuel for diesel engines with improved lubricating properties, the wear scar diameter is reduced to 232 microns, according to EN 590: 2009, this value standard is up to 460 microns. The optimal quantitative composition of three-component environmentally friendly diesel fuel with improved lubricity was established. The dependence of the change in the lubricating properties of environmentally friendly diesel fuel on the quantitative and qualitative composition are established. A mathematical equation describing the dependence of the change in the corrected wear spot on the amount of anti-wear additive in the green diesel fuel is derived. Three-component compositions of environmentally friendly diesel fuel make it possible to obtain fuel that meets the requirements of the EN 590: 2009 standard and to expand the resources for obtaining fuel, as well as to improve the environmental and operational characteristics of the fuel.
Treatment of apatite raw materials is associated with the formation of large-tonnage waste – phosphogypsum. The content of rare earth metals in such waste reaches 1 %, which makes it possible to consider it a technogenic source for obtaining rare earth metals and their compounds. Up to the present moment, there are neither processing plants, nor an efficient process flow to handle phosphogypsum dumps. It is rational to use a way that involves extraction of valuable components and overall reduction of phosphogypsum dumps. Such process flow is available with carbonate conversion of phosphogypsum to alkali metal or ammonium sulfate and calcium carbonate upon the condition of associated extraction of rare earth metal (REM) compounds. Associated extraction of REM compounds becomes possible since they form strong and stable complexes with hard bases according to Pearson, which among other things include carbonate, phosphate and sulfate anions. Formation of lanthanide complexes with inorganic oxygen-containing anions is facilitated by the formation of high-energy Ln-O bonds. The study focuses on the dissolution of lanthanide phosphates in carbonate media. It was established that formation of REM carbonate complexes from their phosphates is a spontaneous endothermic process and that formation of lanthanide carbonates and hydroxides serves as thermodynamic limitation of dissolution. A shift in equilibrium towards the formation of carbonate complexes is achieved by increasing the temperature to 90-100 °C and providing an excess of carbonate. The limiting stage of REM phosphate dissolution in carbonate media is external diffusion. This is indicated by increasing rate of the process with an intensification of stirring, first order of the reaction and the value of activation energy for phosphate dissolution from 27 to 60 kJ/mol. A combination of physical and chemical parameters of the process allowed to develop an engineering solution for associated REM extraction during carbonate conversion of phosphogypsum, which included a 4-5 h conversion of phosphogypsum at temperature of 90-110 °C by an alkali metal or ammonium carbonate solution with a concentration of 2-3 mol/l. As a result, a solution with alkali metal (ammonium) sulfate is obtained, which contains REMs in the form of carbonate complexes and calcium carbonate. The rate of REM extraction into the solution reaches no less than 93 %. Rare earth metals are separated from the mother liquor by precipitation or sorption on anion exchange resins, while the excess of alkali metal or ammonium carbonate is returned to the start of the process.
The Viksha iron ore deposit is confined to the Koykarsko-Sviatnavolok sill, where as a part of ore bodies, in addition to the main components - iron and titanium, it contains gold, platinum, and palladium. The purpose of this publication is to determine the type and patterns of noble metal mineralization in gabbro-dolerites of the Koykar-Svyatnavolok sill, to consider the mechanisms of accumulation and localization of precious metals in ore bodies. The repeated occurrence in the section of the intrusion of an association of two rock varieties of contrasting composition (high-iron - titanomagnetite gabbro-dolerites, and high-siliceous - granophyres), as well as the revealed petrographic, petrochemical and geochemical regularities, allow us to consider liquid stratification of magmatic melt as a mechanism for the formation of ore titanomagnetite horizons ( segregation). This liquid immiscibility led to the accumulation of noble metals in the high-iron fluidized liquate in accordance with distribution coefficients of nobel metals between silicate and oxide melts and between melt and fluid. The confinement of noble metal mineralization to sulfide, cobaltite-bornite-chalcopyrite accumulations in ore titanomagnetite horizons has been established, which corresponds to the low-sulfide noble metal type of mineralization. Precious metal mineralization is represented by both native mineral forms (arsenides, sulfoarsenides, antimonides and intermetallides of platinum group metals, gold and silver tellurides, electrum, native gold) and isomorphic impurities in bornite and cobaltite. The relationship between the formation of minerals bearing noble metals and the process of chloritization against the background of the transformation of protolith titanomagnetite is shown. A model for the concentration of precious metals from basaltoid melt in several stages is proposed: enrichment of fluidized high-iron ore liquat with precious metals; their accumulation in the residual fluid and in the sulfide liquid during the crystallization of ore liquat; their partial entry into the hydrothermal solution during fluid cooling and hydrothermal metasomatism of earlier crystals. The localization of noble metals occurred as the residual fluid cooled, due to the destruction of complex chloride and sulfide compounds with noble and non-ferrous metals and the crystallization of sulfide-precious metal paragenesis within the ore horizons.
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