Аннотация.Исследованы вяжущие свойства геополимерной механоактивированной композиции на

Синтез геополимеров на основе золы уноса с применением механоактивацииКалинкин А.М., Гуревич Б

— An yttrium ammonium carbonate with the composition NH 4 Y(CO 3 ) 2 ∙ H 2 O has been prepared by reacting hydrated yttrium oxide with ammonium carbonate at 80°C. The synthesis process has been shown to proceed through crystallization of two intermediate phases: yttrium ammonium hydroxycarbonates differing in composition. The synthesized compounds have been characterized by X-ray diffraction, IR spectroscopy, differential scanning calorimetry, thermogravimetry, and chemical analysis. The first X-ray diffraction characteristics of NH 4 Y(CO 3 ) 2 ∙ H 2 O and crystallographic data for its unit cell have been presented. Thermal decomposition of the yttrium ammonium carbonate has been shown to yield cubic yttrium oxide in the form of fine powder.

The processes occurring during the mechanical activation of a-Fe2O3 (hematite) in the presence of oleic acid in a centrifugal-planetary mill have been investigated. Mechanical activation for 10 h afforded hematite powder with particles size of 10–40 nm, as shown by means of X-ray diffraction analysis, FTIR spectroscopy, high-resolution transmission electron microscopy, and specific surface area measurements. Longer milling has led to mechanochemical transformation of hematite into Fe3O4 (magnetite).

Аннотация.В работе изучена возможность использования механоактивированных серпентинсодержащих горнопромышленных отходов без

ОПРЕДЕЛЕНИЕ ВИДА ХИМИЧЕСКИХ СВЯЗЕЙ В СУЛЬФАТАХ И ФТОРОСУЛЬФАТО-ЦИРКОНАТАХ НЕОДИМА МЕТОДОМ ИК СПЕКТРОСКОПИИЗалкинд О.А., Годнева М

The paper explored the effect of mechanical activation of low-lime hydro removal ash of the Apatity Thermal Power Station on its binding properties without using alkaline and other chemical agents. Mechanical activation was carried out in an AGO-2 centrifugal-planetary mill for up to 400 s. The initial and mechanically activated ash were characterised by X-ray phase analysis, IR spectroscopy, scanning electron microscopy, laser granulometry, and specific surface area measurement. Following on from the data for aqueous leaching the initial mechano-activated ash, and also IR spectroscopy and thermogravimetric analysis, it was determined that mechanical activation significantly increased ash reactivity towards water. Under normal solidification, the compressive strength of ash-based samples after 60-400 s of mechanical activation aged 7 and 28 days was 0.7-1.7 and 1.4-2.2 MPa, respectively.

Thermal decomposition of fluorooxalatozirconates (FOxZs) K 3 ZrF 5 C 2 O 4 , K 2 ZrF 4 C 2 O 4 ⋅ 2H 2 O, KZrF 3 C 2 O 4 ⋅ 3H 2 O, and Zr 4 O 3 F 2 (C 2 O 4 ) 4 ⋅ 2H 2 O in air flow is studied. Crystalline K 2 ZrF 4 C 2 O 4 and KZrF 3 C 2 O 4 are detected. The decomposition onset temperature of anhydrous products goes down as the K/Zr molar ratio decreases. Disproportionation of potassium FOxZs both at the oxalate group yielding K 2 ZrF 4 C 2 O 4 and ZrO 2– x /2 F x , K 2 C 2 O 4 and K 3 ZrF 7 and at fluorine yielding K 3 ZrF 7 and ZrO 2 takes place. FOxZs can be used as precursors to produce fine-grained ZrO 2 (baddeleyite).

The system ZrO(NO 3 ) 2 -H 2 C 2 O 4 -KF-H 2 O was studied in the sections C 2 O 4 2− : Zr = 1 and 2. The following compounds were isolated: crystalline fluorooxalate zirconates K 3 ZrF 5 C 2 O 4 , K 2 ZrF 4 C 2 O 4 · 2H 2 O, KZrF 3 C 2 O 4 · 3H 2 O, and KZr 2 (OH) 3 F 2 (C 2 O 4 ) 2 · 4H 2 O, and also oxofluorozirconate K 2 Zr 3 O 2.5 F 9 · 7H 2 O and oxofluoride oxalate Zr 4 O 3 F 2 (C 2 O 4 ) 4 · 2H 2 O. A crystalline phase and X-ray amorphous phases of undetermined compositions were detected. All the compounds, except K 2 ZrF 4 C 2 O 4 · 2H 2 O, were obtained for the first time; the crystals KZrF 3 C 2 O 4 · 3H 2 O, KZr 2 (OH) 3 F 2 (C 2 O 4 ) 2 · 4H 2 O, and K 2 Zr 3 O 2.5 F 9 · 7H 2 O were mechanically picked up from a mixture of phases. The composition KZr 2 (OH) 3 F 2 (C 2 O 4 ) 2 · 4H 2 O is conditional. The phases were identified by X-ray powder diffraction, crystal-optical, and elemental analyses, and also by X-ray microanalysis and IR spectroscopy.

We have studied the feasibility of improving the reactivity of ferromagnesian slag through the mechanical activation of the slag with small additions of carbonate minerals in a centrifugal planetary mill. The results demonstrate that, like in the case of the mechanical activation of the slag in a carbon dioxide atmosphere, the process leads to a similar carbonization product, which is considerably more capable of hydraulic hardening than is the slag mechanically activated in air. The highest strength is offered by slag-carbonate materials containing 0.25–1 wt % carbonate (in terms of CO 2 ).

Methods were developed for preparing Ta2O5:Zn alloys containing less than 3 wt % Zn2+ for the purpose of using them further in preparing lithium tantalate batches and growing from them single crystals having improved properties. A method where zinc is doped directly into a tantalum-containing back-extract followed by precipitation of tantalum and zinc hydroxides with ammonia is confined to a Zn2+ concentration of 1.7 wt % in Ta2O5; at higher concentrations, Zn2+ forms soluble ammine complexes. A method where Zn2+ is extracted by high-purity tantalum hydroxide is applicable within the range of Zn2+ concentrations studied. Optimal conditions were found for preparing Ta2O5:Zn2+ alloys of various compositions. X-ray powder diffraction and IR spectroscopy were used to study the phase composition of the alloys synthesized, and Zn2+ concentrations were determined at which a ZnTa2O6 phase was formed along with the major Ta2O5 phase.

Разработаны методы получения лигатур Ta2O5:Zn, содержащих менее 3 мас. % Zn2+, с целью их дальнейшего использования для синтеза шихты танталата лития и выращивания из нее монокристаллов с улучшенными свойствами. Установлено, что способ, основанный на введении примеси цинка непосредственно в танталсодержащий реэкстракт с последующим осаждением гидроксидов Ta и Zn аммиаком, ограничивается значением концентрации 1.7 мас. % Zn2+ в Та2О5, выше которого ионы Zn2+ образуют растворимые амминные комплексы. Метод, основанный на сорбции катионов Zn2+ высокочистым гидроксидом тантала, применим в исследованном диапазоне концентраций Zn2+. Найдены оптимальные условия получения лигатур Та2О5:Zn2+ различного состава. Методами рентгенофазового анализа и ИК-спектроскопии изучен фазовый состав синтезированных лигатур, определены концентрации Zn2+, при которых наряду с основной фазой Та2О5 образуется фаза ZnTa2O6.

Potassium, rhubidium, and caesium fluorophosphatozirconates (hafnates) and oxo(hydroxo)fluorophosphatonitratometalates with PO 4 3− /Zr molar ratios of 2.0, 1.5, 1.0, 0.66, 0.5, and 0.33 are synthesized for the first time. Most of them form either fine crystalline or X-ray amorphous particles. In order to characterize them IR spectroscopy and SEM are used. For the crystalline compounds the types of PO4 groups and the character of bonds between fluorine and water are revealed. The occurrence of triple MeF4·Rb(PO4)0.33·RbNO3 (Me = Zr, Hf) salts and also M3Me3(PO4)5·3HF crystalline solvates is found. The layered habit of K3Hf3(PO4)5·3HF, RbHfF2PO4·0.5H2O, Rb3Hf3(PO4)5·3HF, CsHfF2PO4·0.5H2O, CsHf2F6PO4·4H2O, and CsH2Hf2F2(PO4)3·2H2O crystals gives grounds to suppose that the structure of these compounds is layered unlike the structure of triple MeF4·Rb(PO4)0.33·RbNO3 salts.

Concentrated alkali solutions of niobium containing up to 238 g/L of Nb2O5 have been obtained by sintering of Nb2O5 with K2CO3 · 1.5 H2O. These solutions are recommended for use in the production of welding and other functional materials.

The phase formation in the system HfO(NO3)2-H3PO4-CsF(HF)-H2O was studied along the sections at the molar ratios PO 4 3− /Hf = 0.5, 1.5, and 2.0 and RbF:Hf = 1–5, and also in the presence of HF at CsF: Hf = 1. The initial solutions contained 2–24 wt % HfO2. The synthesis was performed at room temperature. The following substances were isolated: crystalline cesium fluorophosphate hafnates CsHf2F6PO4 · 4H2O, CsHfF2PO4 · 0.5H2O, and CsH2Hf2F2(PO4)3 · 2H2O; X-ray amorphous cesium fluorophosphate hafnate of the average composition Cs2Hf3O1.5F5(PO4)2 · 5H2O; and X-ray amorphous cesium fluorophosphate nitrate hafnate Cs5H4Hf3F7(PO4)3.66(NO3)3 · 5H2O. The compositions of the amorphous phases should be refined. Cesium fluorophosphate hafnates were obtained for the first time. The compounds were studied by crystal-optical, elemental, X-ray diffraction, IR spectroscopic, and electron microscopic analyses.