Fluorination of beryllium concentrates with ammonium fluorides

New method for processing of beryllium ores to beryllium oxide was suggested and studied. The method is based on decomposition of bertrandite or phenacite with ammonium chloride, with the subsequent leaching of ammonium tetrafluoroberyllate and precipitation from a beryllium hydroxide solution. The thermodynamic characteristics were calculated and a thermogravimetric analysis of the process was made. The kinetics of beryllium oxide fluorination with ammonium fluoride was experimentally studied. A technological scheme of a closed cycle for processing of beryllium-containing raw materials with ammonium fluoride was suggested.     

Chlorination of copper-containing raw material by ammonium chloride

A new method of processing the copper-containing raw material to copper(II) oxide was suggested and examined based on the chlorination of copper-containing raw material with ammonium chloride followed by dissolution of copper chloride, precipitation of copper hydroxide from a solution and its calcining to copper(II) oxide. Thermogravimetric analysis of the process was conducted. Kinetics of chlorination of copper(II) oxide by ammonium chloride was experimentally investigated. Technological scheme of the copper-containing raw material processing with ammonium chloride was suggested.     

Elaboration of nanometric amorphous silica from quartz-based minerals using the fluorination method

A method of elaboration of nanometric amorphous silica is proposed using a rational processing of quartz-based ores with the help of a fluorination method. The different steps of the process are described, including the kinetics of the interaction mechanism of ammonium bifluoride with the initial raw materials, the sublimation of ammonium fluorosilicate and the formation of nanometric amorphous silica. Rate constants and activation energy of the chemical reactions are calculated.     

Preparation of High-Purity Iron by Means of Ammonium Chloride Complexes

A method for the preparation of high-purity iron via the chlorination of a mixture containing iron(III) oxide by ammonium chloride with the subsequent decomposition of the intermediate product to iron(III) chloride, its sublimation, and further reduction in a hydrogen flow was proposed. The reaction between ammonium chloride and iron(III) oxide and the thermal decomposition of the ammonium chloride complex were thermogravimetrically studied. The conditions and energetic characteristics of these reactions were determined. The method was tested on iron-containing raw materials. The impurities in the end product of reduction by hydrogen were 0.25%.     

Germanium liquid crystals

Liquid-crystalline compounds containing germanium atoms were synthesised and assessed for liquid-crystalline properties. These new compounds generally possess smectic C phases, and many also possess nematic, smectic A and higher order smectic phases. The germanium-containing liquid crystals were incorporated into smectic C mixtures. These mixtures tend to exhibit little change in smectic C*?layer thickness over temperature. This characteristic is associated with de Vries smectic A materials, but measurements show that, although they have high smectic C stability, the materials' smectic cone angles are small. Measurement of smectic cone angle versus temperature of an exemplar material and its analogues containing carbon and silicon in place of the germanium, all show small cone angles which fall smoothly and extrapolate to zero as the smectic C*?to smectic A transition is approached. These measurements largely explain the observed small layer changes and establish that the materials are not first-order de Vries materials. They must be located elsewhere along the de Vries-orthogonal continuum of smectic A phases.     

Influence of the amount of ammonium hydrogen difluoride on the degree of fluorination of mineral raw materials

The degree of fluorination and recovery of the main components from mineral raw materials were examined in relation to the amount of ammonium hydrogen difluoride NH₄HF₂.     

Anhydrous oxygen-free rare earth material preparation and characterization

The present paper addresses the preparation and characterization of anhydrous oxygen-free rare earth materials, such as terbium fluoride (TbF₃). The fluorination of terbium oxide (Tb₄O₇) by ammonium bifluoride (NH₄HF₂) to prepare anhydrous TbF₃ was reported in this work. The parameters affecting fluorination were studied, including the fluorination temperature, excess stoichiometric amount of NH₄HF₂, and time for fluorination. The temperatures of Tb₄O₇ fluorination by NH₄HF₂ determined by thermogravimetric analysis and differential thermal analysis ranged from 350°C to 500°C. The phase structure of the as-prepared products identified by the X-ray diffraction method was indexed to the orthorhombic phase of TbF₃ [space group: Pnma (no. 62)] that exhibited good accordance with the values in the standard cards JCPDS No. 37-1487 for TbF₃. Energy-dispersive X-ray spectroscopy (EDS) methods were used to analyze the elemental compositions in the as-prepared products; the fluorine (F) and terbium (Tb) elemental compositions calculated from the [TbF₃] formula are in good agreement with those calculated from the EDS pattern. The optimum parameters for fluorination were determined from the results, and anhydrous oxygen-free TbF₃ can be used to study the preparation of metallic terbium by the calcinothermic reduction method.     

Reaction of magnesium oxide and magnesium silicates with ammonium hydrodifluoride

The reactions of magnesium oxide and magnesium silicates (forsterite and serpentines) with ammonium hydrodifluoride is studied using DTA, X-ray powder diffraction, and IR spectroscopy. The conditions for the formation of intermediate phases are determined. The structure of the silicate mineral does not significantly affect the fluorination.     

Impurity paramagnetic Fe(III) and Mn(II) centers in samples of amorphous silica of different origin

Some important magnetic and local structural properties of amorphous silica separated from biogenic (fruit shell of rice and oats, larch and Korean spruce needles, horsetail pedicels, and diatomic algae) and mineral raw were determined by the method of electron paramagnetic resonance. The data obtained can be useful when selecting raw materials and for development of processing scheme of its treatment to separate silicon(IV) oxide with required characteristics.     

Organotrichlorogermane synthesis by the reaction of elemental germanium, tetrachlorogermane and organic chloride via dichlorogermylene intermediate

Organotrichlorogermanes were synthesized by the reaction of elemental germanium, tetrachlorogermane and organic chlorides, methyl, propyl, isopropyl and allyl chlorides. Dichlorogermylene formed by the reaction of elemental germanium with tetrachlorogermane was the reaction intermediate, which was inserted into the carbon-chlorine bond of the organic chloride to give organotrichlorogermane. When isopropyl or allyl chloride was used as an organic chloride, organotrichlorogermane was formed also in the absence of tetrachlorogermane. These chlorides were converted to hydrogen chloride, which subsequently reacted with elemental germanium to give the dichlorogermylene intermediate. The reaction of elemental germanium, tetrachlorogermane and organic chlorides provides a simple and easy method for synthesizing organotrichlorogermanes, and all the raw materials are easily available.     

On the Possibility of Separation of Ammonium Bisulfate into Sulfate and Acid in the Cyclic Salt-Type Processing of Alumina-Containing Raw Materials

The bisulfate process is promising for the development of closed cycle technologies for the processing of alumina-containing raw materials with reagent recovery. Implementing this process requires a rational method for separation of ammonium bisulfate into the sulfate and sulfuric acid in each cycle. The possibility of such separation was shown for the first time by modification of the acid retardation technique based on the sieve effect in the nanoporous medium. The proposed method solves the problem of reagent recovery, which is relevant for some industrial processes, and has prospects for the development of new ore processing techniques.     

EDTA滴定法测定含锌物料中氧化锌

采用氯化铵-氨水体系溶解试样,干过滤后,向移取的滤液中加入氯化钡和硫酸共沉淀铅离子,过滤分离硫酸铅沉淀,向滤液中加人抗坏血酸、氟化钾、硫代硫酸钠等掩蔽剂掩蔽少量干扰元素。在pH=5~6的乙酸-乙酸钠缓冲溶液中,以二甲酚橙为指示剂,用EDTA标准滴定溶液滴定测得结果为氧化锌、水溶性锌和镉合量,扣除由原子吸收光谱法测得的水溶性锌量和镉量,即为氧化锌量。对总氨浓度、氯化铵-氨水浓度比、溶液加入量、搅拌时间、共存离子干扰、精密度等进行了实验,建立了EDTA滴定法测定含锌物料中氧化锌物相的分析方法。实验证明,氧化锌含量在24%~83%时,方法精密度(RSD)为0.25%~0.54%,加标回收率在99%~104%,完全满足含锌物料中氧化锌的测定要求。     

关于合成Ge—132所用Ge原料其残留无机锗的问题

Ｇｅ－１３２中的无机锗含量是一个重要的质量指标。它主要来自ＧｅＨＣｌ３中的ＧｅＣｌ４,而无论哪种锗原料合成Ｇｅ－１３２,ＧｅＨＣｌ３都是中间产物。与用金属Ｇｅ和ＧｅＯ２制备Ｇｅ－１３２的工艺比较,用ＧｅＯ２的盐酸溶液比用金属Ｇｅ在高温下与ＨＣｌ气反应制备ＧｅＨＣｌ３更利于降低Ｇｅ－１３２中残留的无机锗含量。     

混合价黑色氧化铕的制备及其性质初步研究

用含肼甲酸铕在Ｎ２气氛中热分解的方法制得了混合价黑色氧化铕粉末。对它的有关物理化学性质进行了初步研究,得到了相应的结论。     

高效液相色谱法测定人参单体皂甙的研究──醋酸铵对人参皂甙分离的色谱改性

讨论了醋酸铵对高效液相色谱法（ＨＰＬＣ）分离人参单体皂甙的色谱改性情况,经试验选择采用ＭＰＧ－ＯＤＳ色谱柱,ＵＶ２０４ｎｍ处检测,以乙腈－水－醋酸铵为流动相,在１５分钟内较好地分离了单体皂甙Ｒ＿（ｇ２）、Ｒ＿（ｂ１）、Ｒ＿ｃ、Ｒ＿ｄ、Ｒ＿（ｇ１）、Ｒ＿ｅ等。方法操作简单、快速,可用于人参质量评定的常规分析。     

A new method for the synthesis of silicon-and germanium-containing 2-acetylfurans and 2-acetylthiophenes

A new method was developed for the synthesis of silicon-and germanium-containing acetylfurans and acetylthiophene by metallation of 2-acetylfuran or 2-acetylthiophene with n-BuLi at low temperature after protection of the carbonyl group with lithium N-methylpiperazide and reaction of the lithium derivative with various trialkyl-, alkylphenyl-, and cycloalkylchlorosilanes or trialkylchloro(bromo)germanes. The cytotoxic activity of the new compounds was studied, and it was established that the silicon-and germanium-containing acetylfurans and acetylthiophenes are substances with low toxicity (LD₅₀ 312->2000 mg/kg) and have low cytotoxicity toward HT-1080 and MG-22A tumor cells. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 192–199, February, 2007.     

A study of the mechanism and kinetics of interaction between nepheline powder and ammonium hydrofluoride

Behavior of a skeleton silicate, nepheline, in the reaction of fluorination with ammonium hydrofluoride was studied by means of differential-thermal, X-ray phase, and chemical analyses, IR spectroscopy, and scanning electron microscopy.     

Synthesis and photoluminescent properties of size-controlled germanium nanocrystals from phenyl trichlorogermane-derived polymers

We report the preparation of luminescent oxide-embedded germanium nanocrystals (Ge-NC/GeO2) by the reductive thermal processing of polymers derived from phenyl trichlorogermane (PTG, C6H5GeCl3). Sol-gel processing of PTG yields air-stable polymers with a Ge:O ratio of 1:1.5, (C6H5GeO1.5)n, that thermally decompose to yield a germanium rich oxide (GRO) network. Thermal disproportionation of the GRO results in nucleation and initial growth of oxide-embedded Ge-NC, and subsequent reaction of the GeO2 matrix with the reducing atmosphere results in additional nanocrystal growth. This synthetic method affords quantitative yields of composite powders in large quantities and allows for Ge-NC size control through variations of the peak thermal processing temperature and reaction time. Freestanding germanium nanocrystals (FS-Ge-NC) are readily liberated from Ge-NC/GeO2 composite powders by straightfoward dissolution of the oxide matrix in warm water. Composites and FS-Ge-NC were characterized using thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), selected area electron diffraction (SAED), energy dispersive X-ray spectroscopy (EDX), and photoluminescence (PL) spectroscopy.     

Fluoride processing of non-bauxite ores

Integrated processing of non-bauxite ores using ammonium hydrogen difluoride was studied. The kinetics of sintering of the raw material, sublimation of ammonium hexafluorosilicate, and formation of aluminum fluoride and alumina were described. The rate constants and activation energies of the reactions were determined.