Purification of wet process phosphoric acid by desulfurization and ammonization

We studied the processes of desulfurization of phosphoric acid obtained by wet process from washed and roasted concentrate and subsequent purification of acid from bivalent and trivalent metals and fluorine via partial ammonization (at pH of 2 to 4). Purified ammoniated slurry containing 16.96% P2O5, 8.06% N, 0.09% CaO, 0.58% MgO, 0.004% Fe2O3, 0.031% A12O3, 0.78% SO3 and 0.52% F was fabricated by the removal of precipitates at the stages of desulfurization and partial ammonization. The rheological properties of ammoniated slurry with 40% moisture were studied. When the temperature is increased from 40 to 800C, both the density and viscosity decrease from 1.395 to 1.365 g cm–3 and from 80.8 to 48.7 cP, respectively. Ammoniated suspension with pH of 5.5 and 8.5 was applied to prepare mono- and diammonium phosphates with the ratio P2O5:N of 52:14 and 48:18, respectively. The sludge obtained after desulfurization and ammonization processes can be used as a slow-release fertilizer.

A new class of anionic metallohelicates based on salicylic and terephthalic acid units, accessible in solution and by mechanochemistry

We present a new class of anionic metallohelicates based on an abundant, industrially relevant salicylic acid derivative, leading to discrete double and triple-stranded architectures based on divalent and trivalent metals...

Dependence of the fire retardant and fire extinguishing efficiency of compositions based on phosphates of bivalent and trivalent ammonium metals on their physicochemical properties

Purpose. The object of research were fire-retardant and fire-extinguishing agents based on ammonium phosphates of bivalent and trivalent metals used for the treatment of forest combustible materials (FCM), including wood and peat. The subject of the research was to determine the fire-retardant and fire-extinguishing effectiveness of these agents, depending on their physical and chemical properties determined by the conditions of synthesis. The aim was to establish common traits or difference in the mechanism of inhibition of combustion of FCM by metallophosphate systems of various chemical compositions, as well as to reveal the role of the processes occurring in the condensed phase under the influence of their thermal decomposition products. The main task was to study the physicochemical, thermal properties of fire-retardant and fire-extinguishing agents, as well as fire-protected samples of peat and other FCM in the temperature range on the burning surface of natural materials (200–500 °C). Methods. X-ray phase analysis, differential scanning calorimetry, chemical analysis. Findings. The factors determining the fire-retardant and fire-extinguishing efficiency of synthetic agents based on phosphates of bivalent and trivalent ammonium metals with controlled properties depending on the synthesis conditions with respect to FCM, wood and peat have been determined. A process has been established that has a dominant effect on stopping their combustion – inhibition of radical reactions in the gas phase by volatile nitrogen-containing products. At the same time, it was shown that when developing new fire-retardant and fire-extinguishing agents, it is necessary to take into account their properties such as the ability to form thermal insulating structures in the condensed phase. Application field of research. The results obtained in this work can be used to create new fire-retardant and fire-extinguishing synthetic compositions based on ammonium phosphates of bivalent and trivalent metals for the treatment of forest fuels.

EXPERIMENTAL STUDY OF THE OPERATION OF ION-EXCHANGE MEMBRANES

The possibility of using ion-selective membrane systems based on alizarin and aluminone in measuring the quantitative composition of ions of certain trivalent metals in technological aqueous media and wastewater is considered and experimentally confirmed

The 3-Dimensional g-Deformed Harmonic Oscillator and a Unified Description of Magic Numbers of Metal Clusters

Magic numbers predicted by a 3-dimensional (/-deformed harmonic oscillator with u9(3) D soq(3) symmetry are compared to experimental data for atomic clusters of alkali metals (Li, Na, K, Rb, Cs), noble metals (Cu, Ag, Au), divalent metals (Zn, Cd), and trivalent metals (Al, In), as well as to theoretical predictions of jellium models, Woods-Saxon and wine bottle potentials, and to the classification scheme using the 3n + / pseudo quantum number. In alkali metal clusters and noble metal clusters the 3-dimensional çr-deformed harmonic oscillator correctly predicts all experimentally observed magic numbers up to 1500 (which is the expected limit of validity for theories based on the filling of electronic shells), while in addition it gives satisfactory results for the magic numbers of clusters of divalent metals and trivalent metals, thus indicating that ug(3), which is a nonlinear extension of the u(3) symmetry of the spherical (3-dimensional isotropic) harmonic oscillator, is a good candidate for being the symmetry of systems of several metal clusters.

DOUBLE MOLYBDATES-TUNGSTATES SYSTEM MR(EO4), WHERE M – NH4, Ag, Cu, Tl, R – TRIVALENT METAL, E – Mo, W

More than 120 double tungstates and molybdates of general formula MR(EO4), where M – NH4, Ag, Cu, Tl; R – trivalent metals, E – W, Mo; R – Bi (excepting compounds contained NH4), La – Lu, Y, Sc (excepting compounds contained Cu (I)), In (excepting compounds contained NH4 and Tungsten) were isolated by co-precipitating from aqua solutions, or by solid-phase synthesis. All above mentioned compounds were studied by chemical analysis, thermogravimetry, X-ray and IR spectroscopy. Different numbers structural types were discovered into rows double tungstates and molybdates of composition MR(EO4)2: NH4R(WO4)2 – 3; NH4R(MoO4)2 – 3; AgR(WO4)2 – 4; AgR(MoO4)2 – 5; CuR(WO4)2 – 3; CuR(MoO4)2 – 5; TlR(WO4)2 – 8; TlR(WO4)2 – 11. Most wide among of its are sheyelit CaWO4, types: of KY(MoO4)2, α-KNd(WO4)2, α-KY(WO4)2, of its structural-distorting modifications and structures similar for glazerit. The calculation of meaning ΔHo298 MR(EO4)2, M – alkali metals, NH4, Cu, Ag; E – Mo, W, R – M (II) by method of Kaganyuk D.S. was executed. Dependence ΔHo298 for 300 compounds from radii ratio of mono- and trieevalent metals wаs presented in form of diagrams, it was provided possibility to unite all compounds in only system, where wide areas broadening of structural types were determinated. This diagrams is showing boundaries of structural types, is foreseeing building of unknown like that compounds and is forecasting isomorphic substitution in double tangstats and molybdates of composition MR(EO4)2. It is necessary in processes of preparation of materials for lasers, colouring luminophores, catalyzers, semiconductors, segneto- and piezoelectrics and other materials. It was designed the refined diagrams described regions of structural types of synthesized compounds existing. The formation regularities of different types of polymorphic modifications for crystal structures of the isolated compounds depending on the radii ratio of mono- and trivalent metals have been established. It was compiled a database for materials based on the studied compounds.

Metal replacement in perovskite solar cell materials: chemical bonding effects and optoelectronic properties

Lead replacements with mono-, di-, and trivalent metals are reviewed and discussed with respect to their resulting optoelectronic properties.