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1.
In order to prepare iron phosphate by waste sludge, we report a method for effective utilization of the sludge obtained from the electrocoagulation treatment of source-separated urine. The sludge was dissolved with hydrochloric acid and pretreated with H2O2 and Na3PO4; finally, NaOH was added to precipitate iron phosphate from the solution. Thermal treatment of the precipitate at 750 °C in air yielded crystalline quartz-like anhydrous FePO4. The precipitate was characterized by a number of thermal techniques such as thermogravimetry/differential thermal analysis, scanning electron microscopy, and X-ray powder diffraction.  相似文献   

2.
Nesquehonite, synthesized in the laboratory, can be readily altered to hydromagnesite via an intermediate phase which is morphologically similar to hydromagnesite. This intermediate phase exhibits an X-ray pattern similar to that of the newly discovered mineral dypingite. The transformation is accompanied by a large loss of water, with resulting increase in magnesium. Chemical analysis indicates that dypingite occurs in a range of phases from slightly altered nesquehonite to hydromagnesite. The alteration of nesquehonite at 52°C is exceedingly rapid, explaining why hydromagnesite is the more common hydrate in nature. This formation of a new mineral via the aqueous phase also occurs in the solid state at temperatures in excess of 100°C, as indicated by differential thermal analysis and thermal gravimetric analysis.  相似文献   

3.
The paper presents the results of an experimental study of thermal effects on the mechanical behaviour of a saturated clay. The study was performed on CM clay (Kaolin) using a temperature-controlled triaxial apparatus. Applied temperatures were between 22 and 90°C. A comprehensive experimental program was carried out, including: (i) triaxial shear tests at ambient and high temperatures for different initial overconsolidation ratios; (ii) consolidation tests at ambient and high temperatures; and (iii) drained thermal heating for different initial overconsolidation ratios. The obtained results provide observations concerning a wide scope of the thermo-mechanical behaviour of clays. Test results obtained at 90°C were compared with tests performed at ambient temperature. Based on these comparisons, thermal effects on a variety of features of behaviour are presented and discussed. Focus is made on: (i) induced thermal volume change during drained heating; (ii) experimental evidence of temperature influence on preconsolidation pressure and on compressibility index; (iii) thermal effects on shear strength and critical state; and (iv) thermal effects on elastic modulus. Thermal yielding is discussed and yield limit evolution with temperature is presented. The directions of the induced plastic strains are also discussed. Several remarks on the difference in the mechanical behaviour at ambient and high temperatures conclude the paper. Copyright © 2004 John Wiley & Sons, Ltd.  相似文献   

4.
The influence of petrographic features on the strength of granitic stones is a wide studied topic which finds different correlations depending on the research and the granite type. The aim of this article was to provide an accurate statistical analysis in which the amount of analysed data did not imply any doubt about the representativity of the samples and the accuracy of the results. The focused principal component analysis was used because it allows to explain a determinate property in relation to several variables. In addition, the expression of the results was done as a simple and graphical representation that allowed to interpret the results in a global way. Data of texture, mineralogy and strength of 12 granites were obtained in this study and were completed by those of more than 100 granites obtained from the literature. The durability of the twelve granite characterized was also assessed. A thermal fatigue test was carried out in 5?×?5?×?5 cm cubes revealing that the thermal expansion experimented by the different minerals was enough to produce variations in the crack network even if temperature was lower than the microfissuration threshold.  相似文献   

5.
This paper deals with the moisture exchanges occurring between soils and the surrounding atmosphere. Convective drying tests are performed on Awans silts at different drying temperatures and air relative humidities in order to reproduce the natural drying conditions. The experiments improve the understanding of the vapour transfers kinetics between the soil samples and the atmosphere. The experimental results are analysed assuming that the transfers take place in a boundary layer existing at the surface of the porous medium. The influence of the thermal conditions on the evaporation is also taken into account. In our model, coupled vapour and energy exchanges are controlled by mass and heat transfer coefficients characterizing the boundary layer. These coefficients are determined from the drying experiments. The modelling of the drying tests in non‐isothermal conditions is performed in order to validate the formulation of the vapour and heat exchanges. The numerical results present a good agreement with the kinetic of the materials desaturation determined during the tests. The analysis of the moisture transport mechanisms into the sample and at the boundary shows that at the beginning of the test, the drying is first achieved by the transport of moisture in its liquid form and its evaporation at the sample outer boundary in contact with the atmosphere. In a second step, vapour diffusion becomes predominant into the sample and it corresponds to the most important decrease of relative humidity. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

6.
Novel sensible thermal storage materials (TSM) were first synthesized via thermally treating the green compact obtained using clay, kaolin tailings, and hematite as major raw materials. The samples were characterized using differential scanning calorimetry and thermogravimetric, X-ray diffraction, thermal conductivities, petrography analysis, Fourier transformation infrared spectroscopy, and scanning electron microscopy. The thermal conductivity of the green compact reached 1.11–1.64 W m?1 K?1 after thermally treated at 200–1,000 °C. The clay component was proven to have a predominant effect on the thermal conductivity of the green compact. Kaolin tailings could act as a “modulator” for adjusting the thermal conductivity from 1.42 to 1.92 W m?1 K?1. Affecting mechanism of microstructural change of main components during sintering on thermal conductivity of TSM was prominently investigated. TSM could provide a potential candidate for thermal energy storage systems of concentrated solar power.  相似文献   

7.
夏 《地质科学》1981,(4):368-375
苏州高岭土矿床可划分为两种成因类型[1,2],即风化型1)和热液蚀变型。高岭土集中分布在阳山东、西、北三个矿区。本文仅就阳西风化型高岭土中产出的不同种类高岭土矿物的形成及其互相演变的关系作初步探讨。  相似文献   

8.
One‐dimensional consolidation analysis of layered soils conventionally entails solving a system of differential equations subject to the flow conditions at the bounding upper and lower surfaces, as well as the continuity conditions at the interface of every pair of contiguous layers. Formidable computational efforts are required to solve the ensuing transcendental equations expressing the matching conditions at the interfaces, using this method. In this paper, the jump discontinuities in the flow parameters upon crossing from one layer to the other have been systematically built into a single partial differential equation governing the space–time variation of the excess pore pressure in the entire composite medium, by the use of the Heaviside distribution. Despite the presence of the discontinuities in the coefficients of the differential equation, a closed‐form solution in the sense of an infinite generalized Fourier series is obtained, in addition to which is the development of a Green's function for the differential problem. The eigenfunctions of the composite medium are the coordinate functions of the series, obtained computationally through the application of the extended equations of Galerkin. The analysis has been illustrated by solving the consolidation problem of a four‐layer composite, and the results obtained agree very well with the results obtained by previous researchers. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

9.
This paper reports the results of our studies, the chemical analysis of thermal spring’s waters and their geological settings, the use of different statistical methods to evaluate the origin of the dissolved constituents of spring waters and the estimation of the reservoir temperature of the associated geothermal fields of the Guelma region, Algeria. A major component in 13 spring water samples was analyzed using various techniques. The waters of the thermal springs at Guelma basin vary in temperature between 20 and 94oC. Q-mode hierarchical cluster analysis suggests three groups. The water springs were classified as low, moderate and high salinity. Mineral saturation indices (SI) calculated from major ions indicate the spring waters are supersaturated with the most of the carbonate minerals, and all of the spring water samples are under-saturated with evaporite minerals. The thermal spring waters have a meteoric origin, and all samples are immature with strong mixing between warm and shallow waters, where the temperatures of reservoirs to which the thermal waters are related ranged between 64° and 124°C. The deep circulation of meteoric waters in the study area is supplied by the high geothermal gradient around 4.5°C per 100 m and reaches a high temperature before rising to the surface. The estimated circulation depths ranged from 1425 and 3542 m.  相似文献   

10.
With the aid of integral transform techniques, this paper presents an extended precise integration solution for thermal consolidation problems of a multilayered porous thermo-elastic medium with anisotropic thermal diffusivity and permeability due to a heat source. From the fundamental governing equations, ordinary differential equations are derived by employing Laplace–Hankel transforms. By applying the extended precise integration method, equations in the transformed domain can be solved, and the actual solutions are further obtained by adopting a numerical inverse transformation. The accuracy and feasibility of the proposed theory is demonstrated by contrastive analysis with existing studies. Finally, several examples are carried out to investigate the influence of heat source’s type, axial distance, burial depth of heat source, ratio of thermo-permeability, permeability anisotropy, thermal diffusivity anisotropy and stratification on the thermal consolidation process.  相似文献   

11.
根据矿物差热曲线特征温度，拟定使用热重差分析岩矿中全碳、结晶水、硫化物硫和二氧化碳等项目的灼烧温度范围，并进行热重差分析。所得的结果与其他方法结果一致。  相似文献   

12.
Thermal waters at the Godavari valley geothermal field are located in the Khammam district of the Telangana state, India. The study area consists of several thermal water manifestations having temperature in the range 36–76 °C scattered over an area of ~35 km2. The thermal waters are Na–HCO3 type with moderate silica and TDS concentrations. In the present study, detailed geochemical (major and trace elements) and isotope hydrological investigations are carried out to understand the hydrogeochemical evolution of these thermal waters. Correlation analysis and principal component analysis (PCA) are performed to classify the thermal waters and to identify the different geochemical processes controlling the thermal water geochemistry. From correlation matrix, it is seen that TDS and EC of the thermal springs are mainly controlled by HCO3 and Na ions. In PCA, thermal waters are grouped into two distinct clusters. One cluster represents thermal waters from deeper aquifer and other one from shallow aquifer. Lithium and boron concentrations are found to be similar followed by rubidium and caesium concentrations. Different ternary plots reveal rock–water interaction to be the dominant mechanism for controlling trace element concentrations. Stable isotopes (δ18O, δ2H) data indicate the meteoric origin of the thermal waters with no appreciable oxygen-18 shift. The low tritium values of the samples originating from deeper aquifer reveal the long residence time (>50 years) of the recharging waters. XRD results of the drill core samples show that quartz constitutes the major mineral phase, whereas kaolinite, dolomite, microcline, calcite, mica, etc. are present as minor constituents. Quartz geothermometer suggests a reservoir temperature of 100 ± 20 °C which is in good agreement with the values obtained from K–Mg and Mg-corrected K–Mg–Ca geothermometers.  相似文献   

13.
A series of strontium- and barium-doped alumina samples were prepared by hydrolysis, in neutral medium, starting from commercial Al2O3, SrCO3, and BaCO3 materials. The precursors thus obtained were calcined under air at 700 °C; then, the bulk and surface properties of the resulting mixed oxides were characterized by nitrogen physisorption, X-ray diffraction (XRD), hydrogen temperature-programmed reduction (H2-TPR), thermogravimetry (TGA), and differential thermal analysis (DTA). Contrary to SrCO3, an addition of BaCO3 to α-Al2O3 increases slightly the specific surface area. XRD patterns essentially reveal the characteristic reflections assigned to α-Al2O3. In agreement with TGA and XRD analysis, strontium and barium carbonates remain after calcination at 700 °C, their decomposition starting above 800 °C. Let us note that this decomposition occurs more readily on AlSr-100 than on AlBa-100 with no apparent relationship with the evolution observed on the specific surface areas. H2-TPR experiments underline a significant bulk reduction of barium and strontium carbonates taking place significantly above 900 °C with similar trend noticed during TGA regarding their thermal decomposition. However, the most relevant observation is related to a sharp enhancement of the reducibility of AlSr-y with the appearance two reduction ranges highlighting the existence of different types of interactions with strontium and the alumina substrate.  相似文献   

14.
Water is the most active component in all geological systems.It has an important effect on the physical properties of minerals and melts.It also plays a key role in the evolution of the Earth.Accurate thermodynamics data on water are currently confined to pressures below 1.0GPa and temperatures below 900℃.Presented in this paper are new data available on the P-T properties of water at pressures up to 5.0GPa,develoged from differential thermal analysis and ultrasonic wave amplitude analysis.It has been found that there may exist another ternary point at 3.0GPa and that ultrasonic wave amplitude change of ice-water transition shows two inflection points above 2.0GPa, consistent with the two peaks of differential thermal curves above 2.0GPa .It may be a new phenomenon which needs further study.  相似文献   

15.
全球变化与地表参数的定量遥感   总被引：17，自引：0，他引：17  
从全球变化研究对遥感获取地表时空多变要素信息的需求 ,论述定量遥感中对地表多尺度空间信息作地学描述的新思路和新方法。在分析了变差图描述方法的特点及其不足的基础上 ,提出了直方变差图的概念 ,通过定义驻点和边界点 ,尝试采用直方变差图分解的方法分析地物空间分布规律 ,并通过一个实验对此方法进行了说明。进而基于对地表空间分布信息的提取 ,将可见光、近红外波段遥感信息用于热红外遥感的地温反演 ,利用地表空间结构和大气温度空间分布模式的差异 ,将热红外遥感图像分为地表贡献和大气贡献两部分 ,通过空间相关性分析 ,寻求从热红外遥感图像中直接分离出大气的空间分布模式的方法 ,以解决地温反演中面临的困难。已有的研究结果说明了在全球变化和定量遥感研究中 ,对地表多尺度空间变化信息作简洁的地学描述的必要性及其重要的应用意义。  相似文献   

16.
《Applied Geochemistry》1997,12(5):693-703
Natural zeolitic material composed of natrolite and thomsonite intergrowths (NAT/THO) was treated in solutions of different initial pH values at 25°C under N2 atmosphere and in 1M KCl as ionic modulator, until pH equilibration. The solid experimental products were studied by means of powder X-ray diffraction (XRD), scanning electron microscopy-energy dispersive system (SEM-EDS), Fourier-transformed infra-red (FTIR) and thermogravimetric analysis/differential thermal analysis (TGA/DTA). The liquid experimental products were analysed using atomic absorption spectroscopy (AAS) and atomic emission spectroscopy (AES). The NAT/THO material exhibited an amphoteric character with a tendency to neutralise the reacting solutions. The pH equilibration was faster for the acidic region than for the basic one. The H+ ions are chemisorbed on the bulk material, whereas the OH− ions promote a proton detachment from the exchangable cation-water complexes. No Brœnsted acidity, possibly responsible for the neutralisation in the basic region, was found by temperature-programmed desorption (TPD) measurements. Reaction mechanisms involving hydrolysis and degradation-dissolution are proposed. Zeolite crystals remaining at the end of the experiments showed no loss of crystallinity, phase transformation nor even framework dealumination. The insertion of K+ into the zeolites is suggested here as the reason as to why no collapse of their crystal structure occurred in the most acidic solutions causing the zeolites to be more resistant to chemical weathering.  相似文献   

17.
Kerogen was isolated from a marine sediment from Tanner Basin, offshore California. Samples of the kerogen were heated under an inert atmosphere at various temperatures and times. The heated and unheated kerogens were subjected to alkaline potassium permanganate oxidation followed by GC/ MS analysis of the products. The kerogens yielded primarily aliphatic C2–C14 α,ω-dicarboxylic acids and benzene mono-to-pentacarboxylic acids. Yields of aliphatic dicarboxylic acids from kerogen decreased with increasing thermal alteration. Yields of benzenecarboxylic acids increased steadily with increasing thermal alteration. The data support the concept that thermal maturation during natural burial of this type of kerogen results in the generation of aliphatic hydrocarbons from an increasingly aromatic residue.  相似文献   

18.
Thermal decomposition, temperatures of four organic Zn complexes were evaluated experimentally by determining the change in sphalerite solubility with temperature in aqueous solutions containing organic compounds. The results show that decomposition takes place at 180°±5°C for lactic acid-Zn complex, 200°±5°C for EDTA-Zn, 240°±5°C for quinone-Zn and 190°±5°C for fulvic acid-Zn. It is also shown that at 190°–200°C sphalerite solubility is 4 to 7 times higher in NaCl solution containing organic compounds than that in NaCl solution without organic compounds. Studies were also conducted on the contents of Pb and Zn complexed by fulvic acid and humic acid in aqueous solutions the infrared spectra of fulvic acid-Zn and humic acid-Zn complexes, the differential thermal analysis of fulvic acid, humic acid and quinone and EDTA, and the variation in fulvic acid solubility in the seawater with temperature.  相似文献   

19.
 The kinetics and mechanism of hydrothermal formation of zeolite A from natural kaolinites have been studied using as starting materials two international kaolinite standards (KGa-1 and KGa-2 from Georgia, USA) exhibiting a different degree of stacking disorder. Precursors utilized for the synthesis were prepared by heating the kaolinites at 800 °C. Metakaolinite was also prepared from KGa-1 by thermal activation at 600 °C. The hydrothermal syntheses were accomplished by heating the samples in NaOH solutions at temperatures between 70 and 110 °C. The kinetic experiments were performed by time-resolved synchrotron powder diffraction in isothermal mode using a transmission geometry and an Image Plate detector. The results of the kinetic analysis are interpreted in the light of the structural state of the starting kaolinite, and of the temperature of activation of the precursor material. For kaolinite activated at high temperature the nucleation and crystallization of zeolite A is essentially independent of the defect density of the original kaolinite, and the thermal history of the precursor seems to be the main controlling parameter. The formation process of zeolite A from metakaolinite materials obtained at lower activation temperatures shows significantly faster reaction rates and lower apparent activation energies. This is again interpreted in the light of the short range inhomogeneities present in metakaolinite. As the reaction proceeds metastable zeolite A transforms into hydroxy-sodalite. Received April 18, 1996 / Revised, accepted September 27, 1996  相似文献   

20.
High resolution thermal cameras were used in observations of gas-and-ash plumes during eruption of the Koryak volcano in March 2009. Our results provide the thermal structure of gas-and-ash flows. The structure of the eruption column consists of several individual plumes. The vertical velocity of plume rise was estimated at 5.5–7 m/s. The eruption column or plume can be conventionally divided into three parts: a highly convective region, a buoyant region, and a region of horizontal motion. The temperature of the plume is higher than that of the surrounding atmosphere by 3–5°C for the horizontal motion region and by about 20°C for the buoyant region. The velocity at the buoyant region is 5–7 m/s. For the boundary between highly convective and buoyant regions, where the plume diameter is known, the vapor mass flow and the heat capacity of the thermal jet flow can be determined from the heat balance equation. The mass flow of the overheated vapor, which has a temperature of 450°C and comprises a gas-and-ash eruption plume, was estimated to be Q = 35 kg/s. The total mass of water vapor over the period of eruption (100 days) is estimated at 3 · 105 t. The total thermal energy of the eruption amounted to 109 MJ.  相似文献   

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