Oxide minerals, thermal analysis

The technique of differential thermal analysis (D.T.A.) has been extensively employed in the study of clay and other minerals for elucidating their structures for more than three decades. The application of D.T.A. as a tool has not been widely made to the systematic study of solid catalysts. Only a few references on the subject could be foimd 1-6). In the present article, differential thermal studies of a number of solid catalysts like chromic oxide gels, ferric oxide gels, and chromic oxide-ferric oxide are reported. An attempt has also been made to correlate the data with x-ray... 

Thermal analysis showed that structural water in the mineral was 12.49% by weight of die total solid. The combination of lOP-MS analysis of die dissolved Mn oxide and a charge balance of die different elements provides a formula for the Mn oxide mineral as Ko.i54Mni.7ge04 l.S5H20. This interpretation assumes that the oxidation state for all Mn inside the mineral is IV. As compared with other results (74), our interpretation seems reasonable. Four independent measurements using the BET method yielded a specific surfitce area for Mn oxide of 23.6 0.82 m /g. Potentiometric titrations of Mn oxide solid found the pzc for Mn oxide to be 3.7 0.4, which is con arable to the range reported (2.0 to 4.5) for different forms of MnOa (75). 

Iron oxides and hydroxides are the most important iron-bearing constituents of soils, sediments and clays. To characterize the samples, i.e. the identification of the different minerals present and the determination of their morphology and chemical composition, a variety of standard techniques are commonly used such as X-ray and electron diffraction, chemical analyses, optical and electron microscopy, infrared spectroscopy and thermal analysis (DTA, DTC,...). Most of these techniques are further applied in conjunction with selective dissolution or other separation methods in order to obtain more specific information about particular components in the complex soil system. In addition to all those characterization methods, MS has proven to be a valuable complementary technique for the study of these kinds of materials and in particular for the characterization of iron oxides and hydroxides which are usually poorly crystallized. 

Very little further progress in instrumentation was made until the 1950s. By 1952 approximately 1,000 research reports on differential thermal analysis had been published. DTA was mainly used to determine phase diagrams, transition temperatures, and chemical reactions, as well as for qualitative analysis of metals, oxides, salts, ceramics, glasses, minerals, soils, and foods. 

Od-fumace blacks used by the mbber iadustry contain over 97% elemental carbon. Thermal and acetylene black consist of over 99% carbon. The ultimate analysis of mbber-grade blacks is shown ia Table 2. The elements other than carbon ia furnace black are hydrogen, oxygen, and sulfur, and there are mineral oxides and salts and traces of adsorbed hydrocarbons. The oxygen content is located on the surface of the aggregates as C O complexes. The... 

Layer charges can be calculated from mineral and chemical composition. Mineral composition can be determined by the comparison of x-ray diffraction and thermal analytical and surface area studies. Chemical composition is determined by a total chemical analysis of the sample. In the classical method, chemical analysis is made after acidic dissolution (Ross and Hendricks 1945). Nowadays, nondestructive analytical methods (e.g., electron microscopy, prompt gamma activation analysis, etc.) are also applied. Chemical composition is usually given as oxides (e.g., Si02, A1203, etc.). The cations are divided into three groups ... 

The BOD method is based on the processes of degradation by bacteria, and there is a range of operational conditions and reactors can be different depending on the manufacturer (biosensors S.L., Kelma, LAR, STIP ISCO). Since the incubation takes several days is no incentive to convert this into an on-site method. For some methods that can be used online an oxidation step is required before analysis, and this can be achieved in a variety of ways, for instance oxidation processes can be based on thermal, catalytic, chemical, or photochemical reactions, for the estimation of COD, TOC, TN and TP in waters and wastewaters. Photochemical oxidation is determined by persulphate and UV irradiation. These oxidation processes may also be coupled for better efficiency. These processes achieve mineralization of TOC, TN and TP into CO2, NO and PO43-, respectively, and these can be detected by a range of sensors. 

In Chapters I and 2, an introduction is made to the synchrotron Mossbauer spectroscopy with examples. Examples include the/ns/tu Mossbauer spectroscopy with synchrotron radiation on thin films and the study of deep-earth minerals. Investigations of in-beam Mossbauer spectroscopy using a Mn beam at the RIKEN RIBF is presented in Chapter 3. This chapter demonstrates innovative experimental setup for online Mossbauer spectroscopy using the thermal neutron capture reaction, Fe (n, y) Fe. The Mossbauer spectroscopy of radionuclides is described in Chapters 4-7. Chapter 4 gives full description of the latest analysis results of lanthanides Eu and Gd) Mossbauer structure and powder X-ray diffraction (XRD) lattice parameter (oq) data of defect fluorite (DF) oxides with the new defect crystal chemistry (DCC) Oq model. Chapter 5 reviews the Np Mossbauer and magnetic study of neptunyl(+l) complexes, while Chapter 6 describes the Mossbauer spectroscopy of organic complexes of europium and dysprosium. Mossbauer spectroscopy is presented in Chapter 7. There are three chapters on spin-state switching/spin-crossover phenomena (Chapter 8-10). Examples in these chapters are mainly on iron compounds, such as iron(lll) porphyrins. The use of Mossbauer spectroscopy of physical properties of Sn(ll) is discussed in Chapter I I. 

This phase transformation is accompanied by a bone expansion, as indicated by the dilatometry analysis presented in Figure 16.2 (1260-1360 °C range) [28]. Traces of calcium oxide and magnesium oxide have been identified [11] in bone specimens (originating to different species) thermally treated at 1400 °C. They were not considered as products of hydroxyapatite decomposition, but reported as mineral phases. 

---