Some Physical, Chemical and Mineralogical Properties of Some Canadian Fly Ashes

1986 ◽  
Vol 86 ◽  
Author(s):  
R. C. Joshi ◽  
B. K. Marsh
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Chemical Properties ◽  
Water Soluble ◽  
Pozzolanic Activity ◽  
Unburned Carbon ◽  
Magnetic Fraction ◽  
Fly Ashes ◽  
Physical And Chemical

ABSTRACTThis paper gives physical and chemical properties of some Canadian fly ashes. Specific surface area, magnetic fraction, water soluble fraction and fraction finer than 45 μm were determined as part of the physical tests. Thermo-gravimetric analyses (TGA) in oxygen and nitrogen were conducted on raw ash samples. The change of pH with time in suspensions of the different ashes in water was also determined. Pozzolanic activity of the ashes with lime for all the ashes was evaluated to measure ash reactivity.The ash activity seems to be related to fineness of the ash measured by the Blaine air permeability method, but not to the fineness measured by nitrogen sorption. Generally the greater the specific surface area, the higher the reactivity of the ash. The correlation was, however, not strong and no other physical or chemical parameter measured in this investigation seems to be related to pozzolanic activity.The results of pH and TGA tests indicated that the ashes differ in many respects from each other. The TGA data suggest that loss on-ignition in many of the ashes is not entirely due to the presence of unburned carbon. Specific surface area determined by various methods seems to provide different values. No characterization parameter was found that was uniquely related to coal type.

scholarly journals Influence of the Calcination Temperature on the properties of The Alumina as Catalyst Support for Catalysis

Paliva ◽  
2020 ◽  
pp. 155-161
Author(s):  
Tomáš Hlinčík ◽  
Veronika Šnajdrová ◽  
Veronika Kyselová
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Calcination Temperature ◽  
Specific Surface Area ◽  
Catalyst Support ◽  
Chemical Properties ◽  
Total Pore Volume ◽  
Temperature Range ◽  
Calcination Temperatures ◽  
Physical And Chemical

Alumina is commonly used in industrial practice as a catalyst support and it is made from boehmite. Depending on the calcination temperature, this mineral is transformed into various crystalline modifications which have different physical and chemical properties. For this reason, the following parameters were determined at different calcination temperatures: length, width, material hardness, specific surface area and total pore volume. The results show that with increasing calcination temperature there have been significant changes which may be important when using the material as a catalyst support, e.g. in the preparation of catalysts or in the design of cat-alytic reactors. The specific surface area, which decreases in the temperature range 450–800 °C, is an important parameter for the preparation of catalysts, so it is appropriate to choose a temperature of 600 °C, when the specific surface area is above 200 m2·g-1. The effect of calcination temperature on the structural transitions of boehmite was also monitored. The results showed that γ-Al2O3 has the most suitable properties as a catalyst sup-port in the temperature range 450–800 °C.

scholarly journals Characterization of Samarium Doped Ceria Powders Having High Specific Surface Area Synthesized by Carbon-Assisted Spray Pyrolysis

2011 ◽  
Vol 485 ◽  
pp. 137-140 ◽  
Author(s):  
Kenichi Myoujin ◽  
Hiroki Ichiboshi ◽  
Takayuki Kodera ◽  
Takashi Ogihara
Keyword(s):  
Specific Surface ◽  
Relative Density ◽  
Spray Pyrolysis ◽  
Surface Area ◽  
Specific Surface Area ◽  
Carbon Sources ◽  
Chemical Properties ◽  
High Specific Surface Area ◽  
Doped Ceria ◽  
Physical And Chemical

Spherical samarium doped ceria (Ce0.8Sm0.2O1.9, SDC) powders having high specific surface area (SSA) were successfully synthesized by carbon-assisted spray pyrolysis (CASP). Saccharides, such as monosaccharides and disaccharides, or organic acids were used as carbon sources. The physical and chemical properties of these powders were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), Thermo gravimetry-Differential Thermal Analysis (TG-DTA), and BET. Decarbonized powders obtained by this method exhibit spherical morphologies and nano- and submicron-sizes. The SSA of SDC obtained from CASP was more than seven times higher than that obtained from conventional spray pyrolysis (CSP). The SSA of the decarbonized SDC powders obtained by calcination at 900 °C was estimated to be approximately 70 m2/g by using the BET method. The relative density of SDC obtained from CASP was higher than that obtained from CSP. The relative density of the SDC pellet was highest (96 %) when it was sintered at 1400 °C.

scholarly journals Preparation of nano manganese oxides by H2O2 in-situ oxidation: effect of regulation mechanism on physical and chemical properties

2021 ◽  
Author(s):  
Mingdong Li ◽  
Jiawei Wang ◽  
Dejin Fu ◽  
Bibo Gou ◽  
Xiaoliang Chen ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Manganese Oxides ◽  
Ph Value ◽  
Chemical Properties ◽  
Manganese Sulfate ◽  
Physical And Chemical Properties ◽  
Physical And Chemical ◽  
And Chemical Properties

Abstract Manganese oxides showed many special physicochemical properties in many fields such as electrochemistry, adsorption and catalysis. They were widely used in cathode materials for lithium batteries, molecular sieves, catalytic materials and adsorbents. In this paper, in situ oxidation of manganese sulfate solution was conducted with H2O2 as oxidant, and the characterization means of XRD, SEM and BET were used. The purpose was to study the effects of different regulation mechanisms on the physical and chemical properties of manganese oxides such as morphology, phase composition, surface properties and specific surface area. The adsorption properties of γ-MnO2 for Co and Ni in manganese ore leaching solution were tested. The results showed as follows. Under alkaline conditions, the main product of manganese sulfate solution oxidized by H2O2 was Mn3O4 spherical particles with a radius of about 50 nm, these particles had micropores or mesopores, the oxidation reaction rate was rapid, and the specific surface area and N2 adsorption capacity changed with the change of reaction conditions.The temperature had a great influence on the micro morphology of the product.The micro morphology was slender nanorod when the temperature was 20℃. With the increase of temperature, the length of nanorod became shorter. When the temperature rises to 50℃, the rod became spherical. When the pH value decreased from 9 to 7, the diffraction peak of each crystal plane in the product Mn3O4 decreased gradually. The diffraction peak of γ-MnO2 appeared when the pH value decreased to 5. All the products were γ-MnO2 when the pH value decreased to 3. With the increase of Mn2+ concentration, the grain size decreased and agglomeration was easy to occur. The optimum conditions were obtained as follows: the temperature was 30℃, pH was 3, reaction time was 90 min, the mole ration of H2O2 to Mn2+ was 1:1, and Mn2+ concentration was 10g/L. Under the optimum conditions, γ-MnO2 with high specific surface area (172.41 m2/g) was prepared. This γ-MnO2 has a good adsorption effect on Co and Ni in manganese ore leaching solution, and the adsorption efficiency could be reached 94.75 % and 95.67 %. This study would provide a reference for the preparation of manganese oxides with different physical and chemical properties.

SYNTHESIS AND CHARACTERIZATION OF FERROELECTRIC NANOCRYSTAL POWDERS OF SrBi2Ta2O9 BY A POLYMERIZABLE COMPLEX METHOD

2005 ◽  
Vol 19 (15n17) ◽  
pp. 2514-2519 ◽  
Author(s):  
JIN-BO CHENG ◽  
AI-DONG LI ◽  
QI-YUE SHAO ◽  
YUE-FENG TANG ◽  
DI WU
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Thermal Analyses ◽  
Water Soluble ◽  
Complex Method ◽  
Powder Synthesis ◽  
Conventional Solid State Reaction ◽  
Transmission Electron ◽  
Average Size

Ferroelectric nanocrystal powders of SrBi2Ta2O9 (SBT) have been first prepared by a polymerizable complex (PC) route. The bismuth powder, strontium carbonate, and water-soluble tantalum oxalate solution were used as starting materials. Thermal analyses (TGA and DSC), x-ray diffraction (XRD), transmission electron microscopy (TEM), and conventional BET method were explored to characterize the structure, morphology, and specific surface area of PC-derived SBT powders calcined at 500-850 °C. As control samples, SBT powders were also fabricated by metalorganic decomposition (MOD) method. The XRD and TEM results indicate that high pure and well crystalline powders can be obtained at 650 °C with a average size of 50 nm. The PC-derived powder has much larger surface area than MOD-derived powder. The BET value of PC and MOD powder at 750 °C for 2h is 6.7 and 1.5m2/g, respectively. The specific surface area of powder prepared by conventional solid-state reaction is quite low, typically less than 1.5m2/g. Therefore, the feasibility of the polymerizable complex route is demonstrated in the powder synthesis of SBT with large surface area.

scholarly journals Optimization of compositions and technology of production of small-clinker floured cements using the most effective fillers

2021 ◽  
Vol 136 (3) ◽  
pp. 46-55
Author(s):  
N.B. Sarsenbayev ◽  
◽  
B.K. Sarsenbayev ◽  
Zh.T. Aimenov ◽  
A.Zh. Aimenov ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Crystalline Structure ◽  
Specific Surface Area ◽  
Chemical Properties ◽  
Surface Layers ◽  
Fine Powders ◽  
Energy Demands ◽  
Actual Evaluation ◽  
Technology Of Production

Considering the physical chemistry of grinding it is worth quoting the grinding of mineral building material as “the change of physical-chemical properties of finely ground materials can not only be due to the reducing the particle sizes, at mechanical grinding significant changes of the crystalline structure of their surface layers (thickness 15-20 microns) take place, in many cases the technological properties of fine powders are not so much due to dispersability but are namely due to the structure rupture”, at that the energy costs for this are “significantly greater than for the exposal of surfaces with a clean cleavage”. The speed of heterogeneous chemical processes involving fine powders is determined primarily not by the magnitude of their specific surface area, as commonly is believed, but by the decrease of energy of activation as the result of crystalline structure rupture and amorphization. However, both specific surface area and energy demands to achieve are actual evaluation of the effectiveness of any material grinding at a particular unit. The main factor of the production process of cements of low water demand is the grinding, characterized by grindability.

scholarly journals Investigations of Latvian Illite/Kaolinite Clays Irradiated Under Action of Accelerated Electrons

2019 ◽  
Vol 26 (1) ◽  
pp. 99-102
Author(s):  
Dāvis CONKA ◽  
Līga AVOTINA ◽  
Ruta SVINKA ◽  
Visvaldis SVINKA ◽  
Laris BAUMANE ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Chemical Properties ◽  
Absorbed Dose ◽  
Free Fraction ◽  
Natural Clay ◽  
Ir Spectrometry ◽  
Accelerated Electrons ◽  
Ft Ir

Natural clay is a perspective material for application as sorbents for wastewater treatment as well as for sorption of radionuclides, where the properties of the clays can be changed under influence of ionizing radiation. For application of Latvian illite/kaolinite clays for isotope sorption it is important to characterize the physic-chemical properties of pre-prepared air dried clays. Two fractions of the illite clays were selected. A fraction with grain size 100 μm (SiO2 content 60.9 ± 1.5 wt.%, specific surface area 35 m2/g) and a sand free fraction – 2 μm (SiO2 47.7 ± 1.9 wt.%, specific surface area 38 m2/g). Selected fractions were irradiated with accelerated electrons (5 MeV, ELU-4, Salaspils, absorbed dose up to 500 kGy). Non-irradiated and irradiated clays were analysed with means of Fourier transform infrared (FT-IR) spectrometry.  

scholarly journals Measuring specific surface area of snow by near-infrared photography

2006 ◽  
Vol 52 (179) ◽  
pp. 558-564 ◽  
Author(s):  
Margret Matzl ◽  
Martin Schneebeli
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Near Infrared ◽  
Two Dimensions ◽  
Chemical Models ◽  
Snow Stratigraphy ◽  
Physical And Chemical

AbstractThe specific surface area (SSA) is considered an essential microstructural parameter for the characterization of snow. Photography in the near-infrared (NIR) spectrum is sensitive to the SSA. We calculated the snow reflectance from calibrated NIR images of snow-pit walls and measured the SSA of samples obtained at the same locations. This new method is used to map the snow stratigraphy. The correlation between reflectance and SSA was found to be 90%. Calibrated NIR photography allows quantitative determination of SSA and its spatial variation in a snow profile in two dimensions within an uncertainty of 15%. In an image covering 0.5–1.0 m2, even layers of 1mm thickness can be documented and measured. Spatial maps of SSA are an important tool in initializing and validating physical and chemical models of the snowpack.

Modification of Fly Ash and its Application State Research in Wastewater Treatment

2013 ◽  
Vol 726-731 ◽  
pp. 2455-2460
Author(s):  
Zhan Hua Wang ◽  
Bing Zhou ◽  
Xue Jing Sun ◽  
Ju Wei Peng
Keyword(s):  
Wastewater Treatment ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Pollutant Removal ◽  
Active Components ◽  
Fly Ashes ◽  
Adsorption Capacities ◽  
Coal Fly Ashes ◽  
Integrated Utilization

Coal fly ashes are a coal combustion product at high temperature. With a certain porous structure and large specific surface area, they have certain adsorption capacities and can be used as the materials for watewater treatment.But limited by the adsorption properties, the raw coal fly ashes have a very low pollutant removal efficiency, and can not meet the practical requirements of wastewater treatment. Therefore, researches now focus on the coal coal fly ashes modification, including increasing the active components in them, enlarging the specific surface area to improve their performance, and to enhance their wastewater treatment effects.Aiming at providing some references of their integrated utilization in wastewater treatment, the modification methods and application status of the coal coal fly ashes are summarized.

scholarly journals Properties of materials for advanced technology of joint utilization of man-made waste

2019 ◽  
Vol 58 (6) ◽  
pp. 97-103
Author(s):  
Igor N. Tanutrov ◽  
◽  
Marina N. Sviridova ◽  
Sergey A. Lyamkin ◽  
Yury A. Chesnokov ◽  
...  
Keyword(s):  
Particle Size ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Granulometric Composition ◽  
Average Diameter ◽  
Water Soluble ◽  
Advanced Technology ◽  
Particle Sizes ◽  
Main Components

With the aim of improving the technology of co-processing of red mud (RM) and oily mill scale free (OMS) using co-temporal methods and apparatus, including using equipment of the center «Ural-M», studied the physico-chemical properties of industrial wastes. The main components of RM are: Fe (35.7%) in the form of hematite and complex hydroalumination, Ca (11.0%) in the form of calcite and hydro-aluminosilicates, Al (6.8%) and Si (4.7%) in the composition of hydroalumination, Na (2.8%) in the form of hydroalumination, carbonate and hydroxide, Ti (2.5%) in the form of rutile. The sludge moisture content was 11.9%. The main components of the OMS are: Fe (71%) in the form of magnetite, wustite and hematite with a very small amount of fayalite. The contents of Si (in the form of quartz), Al and P (non-forming phases) are within 1-3%. Humidity OMS – 16.3%, the content of indelible organic matter – 4.0%. Granulometric composition of RM is characterized by high dispersion. With an average diameter of 1.6 µm, all particle sizes are in the range of 0.5-12 µm. Granulometric composition of OMS is characterized by complexity. With an average diameter of 8.6 µm, maxima of 0.9 µm and 15 µm and a minimum of about 1.2 µm are observed in the particle size distribution. The specific surface area of the materials is equal to RM 23.7 m2/g, and OMS – 1.9 m2/g. The change of waste properties after exposure to aqueous solutions of alkalis and acids neutralizing the effect of organic (OMS) and alkaline (RM) surface compounds was studied. Neutralization of aqueous sus¬pension with HCl solution leads to removal of alkaline film from the surface. As a result of the impact of reagents, there is a decrease in the content of water-soluble components in the processing products. At the same time, the average particle sizes of RM and OMS increase to 2 and 14 µm, respectively, and the specific surface area to 25.7 and 2.3 m2/g. The distribution of particle size of RM is almost constant, and the OMS is approximately 5 and 10% of the smoothed maximum and minimum in the area of at least 0.5 and 15 µm.

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