scholarly journals Possibilities of Use of Isothermal and Isoperibolic Calorimetry to Study the Effect of Zinc on Hydration of Cement Blended with Fly Ash

2020 ◽  
Author(s):  
Pavel Šiler ◽  
Iva Kolářová ◽  
Rdoslav Novotný ◽  
Jiří Másilko ◽  
Jan Bednárek ◽  
...  
Keyword(s):  
Fly Ash ◽  
Alternative Fuels ◽  
Raw Materials ◽  
Alternative Fuel ◽  
Zinc Ions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Secondary Raw Materials ◽  
Isoperibolic Calorimetry ◽  
Poorly Soluble

Increasing utilization of secondary raw materials and alternative fuels results in increasing contents of metals in cements. One of elements, the content of which keeps rising in cement is zinc. It comes to cement with secondary raw materials such as slag or fly ash or by the utilization of used tires as an alternative fuel. Zinc ions significantly prolong the hydration process in cement. This work deals with the influence of zinc ions in the form of very poorly soluble ZnO salt and easily soluble ZnCl2 and Zn(NO)3 on the hydration of cement blended with fly ash. Zinc was dosed in the range of 0.05, 0.1, 0.5 a 1% of cement weight. Final products were next analyzed using X-Ray Diffraction.

scholarly journals Use of Isothermal and Isoperibolic Calorimetry to Study the Effect of Zinc on Hydration of Cement Blended with Fly Ash

Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5215
Author(s):  
Pavel Šiler ◽  
Iva Kolářová ◽  
Radoslav Novotný ◽  
Jiří Másilko ◽  
Jan Bednárek ◽  
...  
Keyword(s):  
Fly Ash ◽  
Alternative Fuels ◽  
Raw Materials ◽  
Zinc Ions ◽  
X Ray Diffraction ◽  
Induction Periods ◽  
Secondary Raw Materials ◽  
Isoperibolic Calorimetry ◽  
Significant Acceleration ◽  
Poorly Soluble

Increasing utilization of secondary raw materials and alternative fuels results in increasing contents of metals in cements. Zinc is one of these elements. It comes to cement with secondary raw materials such as slag or fly ash or by the utilization of used tires as an alternative fuel. Zinc ions significantly prolong the hydration process in cement. This work deals with the influence of zinc ions in the form of very poorly soluble ZnO salt and easily soluble ZnCl2 and Zn(NO3)2 on the hydration of cement blended with fly ash. Zinc was dosed in the range of 0.05%, 0.1%, 0.5% and 1% of cement weight. The effect of zinc on hydration was monitored by isothermal and isoperibolic calorimetry. A 15% addition of fly ash to cement mainly causes further retardation of hydration reactions due to the reactions of fly ash particles with Ca2+ ions from cement. The strongest effect on the hydration retardation from all investigated compounds showed in ZnO as it dissolves very slowly. On the contrary, for the dosage of 1% of zinc in the form of ZnCl2 significant acceleration of hydration occurred. In this work, a synergistic effect on the prolongation of hydration with a combination of cement, zinc and fly ash was demonstrated. The lengths of induction periods were assessed from detected calorimetric curves and from these lengths the curves were gained by fitting with the exponential function. Final products were next analyzed using X-ray diffraction.

scholarly journals Application of Isothermal and Isoperibolic Calorimetry to Assess the Effect of Zinc on Hydration of Cement Blended with Slag

Materials ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 2930 ◽  
Author(s):  
Šiler ◽  
Kolářová ◽  
Novotný ◽  
Másilko ◽  
Bednárek ◽  
...  
Keyword(s):  
Cement Hydration ◽  
Raw Materials ◽  
Isothermal Calorimetry ◽  
Real Life ◽  
Diffraction Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Isoperibolic Calorimetry ◽  
Poorly Soluble ◽  
Furnace Slag

This work deals with the influence of zinc on cement hydration. The amount of zinc in cement has increased over recent years. This is mainly due to the utilization of solid waste and tires, which are widely used as a fuel in a rotary kiln. Zinc can also be introduced to cement through such secondary raw materials as slag, due to increased recycling of galvanized materials. The aim of this work was to determine the effect of zinc on the hydration of Portland cement, blended with ground blast furnace slag (GBFS). This effect was studied by isothermal and isoperibolic calorimetry. Both calorimetry methods are suitable for measurements during the first days of hydration. Isoperibolic calorimetry monitors the hydration process in real-life conditions, while isothermal calorimetry does so at a defined chosen temperature. Zinc was added to the cement in the form of two soluble salts, namely Zn(NO3)2, ZnCl2, and a poorly soluble compound, ZnO. The concentration of added zinc was chosen to be 0.05, 0.1, 0.5, and 1mass percent. The amount of GBFS replacement was 15% of cement dosage. The newly formed hydration products were identified by X-ray diffraction method (XRD).

Influence of Fly Ash on Corrosion Resistance of Refractory Forsterite-Spinel Ceramics

2021 ◽  
Vol 325 ◽  
pp. 181-187
Author(s):  
Martin Nguyen ◽  
Radomír Sokolář
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Corrosion Resistance ◽  
Fly Ash ◽  
Raw Materials ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transition Zones ◽  
Refractory Ceramics ◽  
Scanning Electron

This article examines the influence of fly ash on corrosion resistance of refractory forsterite-spinel ceramics by molten iron as a corrosive medium. Fly ash in comparison with alumina were used as raw materials and sources of aluminium oxide for synthesis of forsterite-spinel refractory ceramics. Raw materials were milled, mixed in different ratios into two sets of mixtures and sintered at 1550°C for 2 hours. Samples were characterized by X-ray diffraction analysis and thermal dilatometric analysis. Crucibles were then made from the fired ceramic mixtures and fired together with iron at its melting point of 1535°C for 5 hours. The corrosion resistance was evaluated by scanning electron microscopy on the transition zones between iron and ceramics. Mixtures with increased amount of spinel had higher corrosion resistance and mixtures with fly ash were comparable to mixtures with alumina in terms of corrosion resistance and refractory properties.

Experimental Study on High Strength Composite Ceramsite Using Fly Ash and Waste Glass

2013 ◽  
Vol 357-360 ◽  
pp. 1337-1342
Author(s):  
Lei Hong ◽  
Wei Cheng
Keyword(s):  
Experimental Study ◽  
Fly Ash ◽  
Raw Materials ◽  
High Strength ◽  
Waste Glass ◽  
Technological Condition ◽  
Test Results ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron

The high strength composite ceramsite was prepared by using fly ash and waste glass as main raw materials and some admixtures such as binder and bubble-forming agent. The suitable technological condition of preparing high strength composite ceramsite was given by studying the influence of the different mix proportions and different sintering systems on the properties of ceramsite. The test results indicate that the compressive strength in cylinder of high strength composite ceramsite which was prepared under certain technological condition can reach 9.9MPa and its bulk density is 974Kg/m3and the water absorption in one hour is 3.6%. The XRD(X Ray Diffraction) and SEM (Scanning Electron Microscope) analyses show that a large number of amorphous gel phases which affect the strength of ceramsite were produced in the process of sintering fly ash and waste glass and abundant even bubbles were formed inside of the ceramsite.

Utilizing Iron Tailing, Sludge and Fly Ash to Prepare Ceramsites

2020 ◽  
Vol 13 (1) ◽  
pp. 16-25
Author(s):  
Zi Wang ◽  
Hongjun Chen ◽  
Chunhu Yu ◽  
Zeyang Xue ◽  
Pengxiang Wang ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Mechanical Performance ◽  
Sintering Temperature ◽  
Raw Materials ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Duration Time

Background: The deposits of iron tailing will pose a great risk of environmental pollution and serious landscape impact which will affect the quality of life of humans. Therefore, it is urgent to utilize iron tailing to produce valuable products. Methods: The tailing ceramsites were analysed by X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM). The roles of the tailing content, sintering temperature and duration time in the performance of the tailing ceramsites were analysed and the optimal sintering parameters were determined. Results: The bulk density, apparent density and cylinder compressive strength of the tailing ceramsites increase considerably with the increase of the sintering temperature and duration time. The cylinder compressive strength of the tailing ceramsites increases with increasing the tailing content. The optimal sintering parameter is 1100°C for 40 min. The cylinder compressive strength of the tailing ceramsites obtained at 1100°C for 40 min reaches 10.1 MPa. XRD analysis shows that the tailing ceramsites mainly consist of CaSiO3, Al2SiO5, MgSiO3, Ca7Si2P2O16, CaAl2Si2O8, Ca2Fe2O5 and SiO2 phases when the sintering temperature and duration time were increased to 1100°C and 40 min, respectively. Conclusion: The tailing ceramsites were obtained from iron tailing, sludge and fly ash as the raw materials at 1100°C for 40 min. The obtained ceramsites exhibited high mechanical performance.

scholarly journals Study of the influence of the secondary raw materials on microstructure and properties of calcium silicate composite

2019 ◽  
Author(s):  
Jana Húšťavová ◽  
Vít Černý ◽  
Rostislav Drochytka
Keyword(s):  
Calcium Silicate ◽  
Raw Materials ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
X Ray ◽  
Autoclaved Aerated Concrete ◽  
Secondary Raw Materials ◽  
Aerated Concrete ◽  
The Difference ◽  
Positive Effect

Calcium silicate composites are a widely used building material, especially autoclaved aerated concrete or sand-lime bricks. The physico-mechanical properties of these materials depend on their microstructure. Microstructure is characterized by the content of crystalline calcium silicate compounds that arise during autoclaving. This is in particular the tobermorite mineral, which carries the mechanical strength of the composite. This paper focuses on the influence of secondary raw materials on properties and microstructure of the calcium silicate composite. Secondary raw materials were selected as slag from the combustion of lignite and ground glass. Mixtures of composites were selected with respect to the required C/S molar ratio of 0.73. The hydrothermal treatment was carried out at a temperature of 190 °C and a residence time of 4, 8 and 16 hours. The microstructure of calcium silicate composites and autoclaved aerated concrete was studied. The use of slag resulted in an increase in the intensity of the diffraction line of tobermorite by X-ray diffraction analysis as well as the use of glass. The difference was particularly evident in the shape of the tobermorite crystals. Long strong crystals were detected in the sample with slag, while the sample with glass exhibited low tobermorite leaves. Porous structure of autoclaved aerated concrete with slag was uniform, unlike samples with glass. Both materials have a positive effect on the increase in compressive strengths of the samples.

Influence of Sinter Temperature on the Hardness of Fly Ash Based Glass Ceramics

2013 ◽  
Vol 357-360 ◽  
pp. 578-581
Author(s):  
Han Ye ◽  
Jing Tian Hou ◽  
Wei Wei Zhang ◽  
Shu Yu Yao
Keyword(s):  
Fly Ash ◽  
Sinter Temperature ◽  
Glass Powder ◽  
Sintering Temperature ◽  
Raw Materials ◽  
Glass Ceramics ◽  
Crystal Phase ◽  
Diffraction Experiment ◽  
X Ray Diffraction ◽  
X Ray

The glass ceramics bricks were prepared by the method of isostatic pressing and one time sintering using fly ash and glass powder as raw materials. X-ray diffraction experiment was performed to identify the main crystal phase. The influence of sinter temperature on the hardness was studied. It was concluded that the main phase were anorthite and albite. The hardness of sample which contains 60% of fly ash attains 766.79MPa when the sintering temperature was 1110°C .The hardness of sample which contains 50% of fly ash attains 780MPa when the sintering temperature was 1075°C.

Tubulin structure at intermediate resolution

1995 ◽  
Vol 53 ◽  
pp. 852-853
Author(s):  
K. H. Downing ◽  
S. G. Wolf ◽  
E. Nogales
Keyword(s):  
High Resolution ◽  
Structural Data ◽  
Therapeutic Drug ◽  
Zinc Ions ◽  
Two Dimensional ◽  
X Ray Diffraction ◽  
X Ray ◽  
Negative Stain ◽  
Functional Mechanisms ◽  
Tubulin Structure

Microtubules are involved in a host of critical cell activities, many of which involve transport of organelles through the cell. Different sets of microtubules appear to form during the cell cycle for different functions. Knowledge of the structure of tubulin will be necessary in order to understand the various functional mechanisms of microtubule assemble, disassembly, and interaction with other molecules, but tubulin has so far resisted crystallization for x-ray diffraction studies. Fortuitously, in the presence of zinc ions, tubulin also forms two-dimensional, crystalline sheets that are ideally suited for study by electron microscopy. We have refined procedures for forming the sheets and preparing them for EM, and have been able to obtain high-resolution structural data that sheds light on the formation and stabilization of microtubules, and even the interaction with a therapeutic drug.Tubulin sheets had been extensively studied in negative stain, demonstrating that the same protofilament structure was formed in the sheets and microtubules. For high resolution studies, we have found that the sheets embedded in either glucose or tannin diffract to around 3 Å.

Studies on the Preparation, Characterization and Solubility of -Cyclodextrin-Roxythromycin Inclusion Complexes

2009 ◽  
Vol 2 (2) ◽  
pp. 523-530
Author(s):  
D. Nagasamy Venkatesh ◽  
S. Karthick ◽  
M. Umesh ◽  
G. Vivek ◽  
R.M. Valliappan ◽  
...  
Keyword(s):  
Dissolution Rate ◽  
Inclusion Complexes ◽  
Phase Solubility ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Ir Studies ◽  
Poorly Soluble ◽  
Poorly Soluble Drug

Roxythromycin/ β-cyclodextrin (Roxy/ β-CD) dispersions were prepared with a view to study the influence of β-CD on the solubility and dissolution rate of this poorly soluble drug. Phase-solubility profile indicated that the solubility of roxythromycin was significantly increased in the presence of β-cyclodextrin and was classified as AL-type, indicating the 1:1 stoichiometric inclusion complexes. Physical characterization of the prepared systems was carried out by differential scanning calorimetry (DSC), X-ray diffraction studies (XRD) and IR studies. Solid state characterization of the drug β-CD binary system using XRD, FTIR and DSC revealed distinct loss of drug crystallinity in the formulation, ostensibly accounting for enhancement of dissolution rate.

scholarly journals Waste and Solar Energy: An Eco-Friendly Way for Glass Melting

2021 ◽  
Vol 5 (2) ◽  
pp. 16
Author(s):  
Isabel Padilla ◽  
Maximina Romero ◽  
José I. Robla ◽  
Aurora López-Delgado
Keyword(s):  
Solar Energy ◽  
Environmental Sustainability ◽  
Raw Materials ◽  
Glass Melting ◽  
Glass Network ◽  
X Ray Diffraction ◽  
X Ray ◽  
Concentrated Solar Energy ◽  
Calcium Source ◽  
The Aluminum Industry

In this work, concentrated solar energy (CSE) was applied to an energy-intensive process such as the vitrification of waste with the aim of manufacturing glasses. Different types of waste were used as raw materials: a hazardous waste from the aluminum industry as aluminum source; two residues from the food industry (eggshell and mussel shell) and dolomite ore as calcium source; quartz sand was also employed as glass network former. The use of CSE allowed obtaining glasses in the SiO2-Al2O3-CaO system at exposure time as short as 15 min. The raw materials, their mixtures, and the resulting glasses were characterized by means of X-ray fluorescence, X-ray diffraction, and differential thermal analysis. The feasibility of combining a renewable energy, as solar energy and different waste for the manufacture of glasses, would highly contribute to circular economy and environmental sustainability.

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