scholarly journals Influence of the gypsum dehydration temperature and alkali additives on the properties of anhydrite cement

2010 ◽  
Vol 42 (2) ◽  
pp. 233-243 ◽  
Author(s):  
V. Leskeviciene ◽  
I. Sarlauskaite ◽  
D. Nizeviciene ◽  
N. Kybartiene
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Compressive Strength ◽  
Crystalline Structure ◽  
Alkali Activation ◽  
Glass Waste ◽  
X Ray ◽  
Gypsum Dehydration ◽  
Scanning Electron ◽  
Sem Analyses

While dehydrating gypsum with additives at the temperatures of 800?C and 900?C the influence of alkali additives on both the crystalline structure of anhydrite and properties of anhydrite binder was investigated. The industrial and household wastes including other lowcost materials were used as additives. Having heated them with gypsum the anhydrite with alkali activation properties was obtained. The properties of such substances were evaluated using the methods of chemical, diffractive X-ray scanning and scanning electron microscopy (SEM) analyses. Some additives, e.g. 5 % ground glass waste, were found to increase crystal agglomerate formation of anhydrite binder, accelerate the hydration process of anhydrite and double the compressive strength of hydrated samples compared to samples without additives.

UTILIZATION OF FLY ASH AND CONCRETE RESIDUE IN THE PRODUCTION OF GEOPOLYMER BRICKS

2017 ◽  
Vol 12 (1) ◽  
pp. 63-77 ◽  
Author(s):  
Siriporn Sirikingkaew ◽  
Nuta Supakata
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Compressive Strength ◽  
Phase Composition ◽  
Fly Ash ◽  
Industrial Waste ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron

This study presents the development of geopolymer bricks synthetized from industrial waste, including fly ash mixed with concrete residue containing aluminosilicate compound. The above two ingredients are mixed according to five ratios: 100:0, 95:5, 90:10, 85:15, and 80:20. The mixture's physico-mechanical properties, in terms of water absorption and the compressive strength of the geopolymer bricks, are investigated according to the TIS 168-2546 standard. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses are used to investigate the microstructure and the elemental and phase composition of the brick specimens. The results indicate that the combination of fly ash and concrete residue represents a suitable approach to brick production, as required by the TIS 168–2546 standard.

scholarly journals Valorization of Brick and Glass CDWs for the Development of Geopolymers Containing More Than 80% of Wastes

Minerals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 672
Author(s):  
Dimitris Kioupis ◽  
Aggeliki Skaropoulou ◽  
Sotirios Tsivilis ◽  
Glikeria Kakali
Keyword(s):  
Electron Microscopy ◽  
Compressive Strength ◽  
Circular Economy ◽  
X Ray Diffraction ◽  
Glass Waste ◽  
X Ray ◽  
Optimum Synthesis ◽  
Synthesis Parameters ◽  
Construction And Demolition Wastes ◽  
Scanning Electron

One of the areas of priority in a circular economy, regarding waste management, regards the valorization of construction and demolition wastes (CDW). This study suggests the synthesis of geopolymeric binders based almost entirely on construction and demolition wastes. Ceramic waste was used as the aluminosilicate precursor of the geopolymer synthesis, while glass waste was applied in the preparation of the activation solution. A fractional experimental design defined the optimum synthesis parameters, based on compressive strength values. The final products were characterized by means of X-Ray Diffraction (XRD), Fourier-Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM). The glass waste was appropriately processed in order to prepare the activation solution for the geopolymerization of brick waste. In this work, CDW-based geopolymers were produced with a compressive strength in the range 10–44 MPa. The developed products contained 80–90 wt.% CDWs, depending on the method of activator preparation.

Characterization of Fluorescent Lamp Glass Waste Powders

2012 ◽  
Vol 727-728 ◽  
pp. 1579-1584 ◽  
Author(s):  
Alline Sardinha Cordeiro Morais ◽  
Thaís Cristina da Costa Caldas ◽  
Sérgio Neves Monteiro ◽  
Carlos Maurício Fontes Vieira
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Glass Powder ◽  
Fluorescent Lamp ◽  
Glass Waste ◽  
X Ray ◽  
Fluorescent Lamps ◽  
Clay Body ◽  
Scanning Electron

Industrialized component wastes, regularly discarded by the society, are increasingly contributing to the environmental pollution. The glass of these lamps is contaminated with mercury, which a serious hazard due to conventional recycling by melting with other glasses. A possible solution could be its incorporation into a clay body to fabricate common fired ceramics such as bricks and tiles. The objective of this work is to characterize a type of glass to be incorporated into a clayey ceramic. The glass analyzed was obtained from fluorescent lamps, which was passed through mercury decontamination process and ground into powder. This glass powder was tested for X-ray fluorescence, DTA/DTG, optical microscopy, scanning electron microscopy and optical dilatometry. The results showed that the glass presents sintering and softening points around 650 °C and 800 °C, respectively. The chemical analysis indicated the presence of impurities in considerable amounts in the composition of the fluorescent lamp glass waste.

scholarly journals Karakteristik Struktur Mikro dan Gugus Fungsi Komposit Silika Sekam Padi dan Aspal

2020 ◽  
Vol 8 (1) ◽  
pp. 93-100
Author(s):  
Ediman Ginting Suka ◽  
◽  
Ira Sudarsono Putri ◽  
Reka Puspitasari ◽  
Reza Arsela ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Compressive Strength ◽  
Functional Groups ◽  
Amorphous Silica ◽  
X Ray Diffraction ◽  
X Ray ◽  
Grain Sizes ◽  
Sample Composition ◽  
Scanning Electron

Composite of rice husk and asphalt silica was carried out at a ratio of 1: 0.7; 1: 0.8 and 1: 0.9 and heated at 150oC for 3 hours. The characteristics of the phase structure, microstructure, and functional groups were analyzed using X-ray Diffraction (XRD), Scanning Electron Microscopy-Energy Dispersive Spectroscopy (SEM-EDS) and Fourier Transform Infrared (FTIR), physical properties analysis (density, porosity) and mechanics (compressive strength). The XRD results showed that the phase in asphalt silica composites detected amorphous carbon at 2θ = 18º and amorphous silica with the amorphous silica peak shifted from 2θ = 22º to 2θ = 20º. Microstructure analysis shows that cracks and clusters are bigger with grain sizes of 7,742 µm, 8,495 µm and 10,921 µm respectively, and the sample composition shows percentage of silicon (Si), Oxygen (O) and sodium (Na), respectively. decreases and the percentage of carbon (C), sulfur (S) increases. The results of FTIR show that the functional groups of Si-OH, Si-O-Si and Si-O bonds are decreasing and the functional groups of C-H bonds are increasing. The addition of asphalt causes the value of density increases, the value of porosity and compressive strength decreases.

scholarly journals Mineralogical, Microstructural and Compressive Strength Characterization of Fly Ash as Materials in Geopolymer Cement

Elkawnie ◽  
2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Cut Rahmawati ◽  
Sri Aprilia ◽  
Taufiq Saidi ◽  
Teuku Budi Aulia
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Compressive Strength ◽  
Fourier Transform ◽  
Fly Ash ◽  
X Ray Diffraction ◽  
Bending Vibration ◽  
X Ray ◽  
Geopolymer Cement ◽  
Scanning Electron

Abstract: This study was designed to examine the mineral, microstructural, and mechanical strength properties of fly ash and its feasibility as a raw material for geopolymer cement. The study used an experimental method by examining the characteristics of fly ash by X-ray Fluorescence Spectrometer (XRF), Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), hydrometer method, Scanning electron microscopy (SEM), and compressive strength testing. For creating the geopolymer cement paste, a concentration of NaOH 10M was used, with a ratio of water/solid = 0.4 and a ratio of Na2SiO3/NaOH = 1 using curring at room temperature. The results showed the geopolymer pastes have a compressive strength of 18.1 MPa and 21.5 MPa after 7 days and 28 days. The XRD results showed a decrease in the peak of 2θ at 26.54° because the amorphous part had transformed into a C-S-H solution in geopolymer cement. This finding was supported by the FTIR spectra results showing Si-O-Si bending vibration and the functional group of AlO2. It showed that Nagan Raya fly ash-based geopolymer is a potential construction material.Abstrak: Penelitian ini dirancang untuk mendapatkan sifat mineral, mikrostruktural, dan kekuatan mekanis dari fly ash serta kesesuaiannya sebagai material dasar pada semen geopolimer. Metode penelitian yang digunakan adalah metode eksperimen dengan cara  menguji karakteristik dari fly ash dengan pengujian X-ray Fluorescense Spectrometer (XRF), Fourier transform infrared (FTIR) spectoscopy, X-ray diffraction (XRD), hydrometer method, Scanning electron microscopy (SEM) dan kuat tekan.  Untuk pembuatan pasta semen geopolimer digunakan konsentrasi NaOH 10 M, rasio water/solid 0,4 dan rasio Na2SiO3/NaOH = 1 dengan perawatan pada suhu kamar. Hasil menunjukkan setelah 7 hari pasta geopolimer memiliki kuat tekan 18,1 MPa dan 21,5 MPa pada 28 hari. Hasil XRD menunjukkan adanya penurunan puncak 2θ pada 26,54° ini disebabkan karena bagian amorf dari fly ash telah menjadi larutan C-S-H pada semen geopolimer. Hasil ini diperkuat dengan analisis FTIR spectra yang menunjukkan adanya Si-O-Si bending vibration dan gugus fungsi dari AlO2. Hasil menunjukkan fly ash dari Nagan Raya potensial sebagai bahan material konstruksi berbasis geopolimer.

Application of Molybdenum ZSM-5 for Catalytic Oxidation of Wastewater Containing Methylene Blue

2020 ◽  
Vol 7 (3) ◽  
pp. 256-264
Author(s):  
Debarpita Ghosal ◽  
D. Kissan Achary ◽  
Sandil Nayak ◽  
Bikash Kumar
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Methylene Blue ◽  
Catalytic Oxidation ◽  
Surface Area ◽  
Crystalline Structure ◽  
Energy Dispersive ◽  
X Ray ◽  
Metal Impregnation ◽  
Scanning Electron

Background:: A vital section of water pollution mostly comes from the dying industry, which contaminates the water bodies by discharging the effluents into them. Naturally, it is carcinogenic as it contains harmful chemicals and minerals. To prevent this , many researchers have studied the issue and came to an inference that Methylene blue should be removed from wastewater. Many researchers and scientists proposed that Zeolite with little modifications could be one of the feasible options for catalytic oxidation of dyes in wastewater. Our focus is mostly based on Molybdenum impregnated H-ZSM-5 to catalytically oxidize methylene blue present in wastewater. Objective:: This method examined the Catalytic oxidation of wastewater containing Methylene Blue by the application of Mo-ZSM-5. Methods:: Raw H-ZSM-5 was activated and impregnated with previously prepared MoCl5 and allowed to dry and calcine at the required temperature. The product was characterized by Scanning Electron Microscopy, Energy Dispersive X-ray Spectroscopy and BET Surface Area Analyser methods. Catalytic oxidation reactions were carried out at room temperature using hydrogen peroxide as oxidant. The effect of each parameter was investigated vividly. Results:: From the Energy Dispersive X-ray Spectroscopy method, it was observed that the percentage for Molybdenum over H-ZSM-5 was 9%. Surface area analysis suggested that the value for the surface area of unimpregnated H-ZSM-5 was 511 m2/g for 5% impregnation and 307 m2/g for 10% metal impregnation. A sharp decrease in the surface area was observed. Scanning Electron Microscopy images depict that the crystalline structure of raw H-ZSM-5 would not be damaged due to metal impregnation. Its shape and size were unaltered. In the images, the porous surface was observed. Conclusion:: Zeolites are an important catalyst in active phases for acidic/basic/redox catalysed reactions. Its activity and selectivity affected by the crystalline structure as well as morphological properties. Molybdenum impregnated H-ZSM-5 catalyst is best popularly known for its shape selectivity property. It promotes faster decomposition of H2O2 to non-reactive O2, which shows poor oxidation activity.

scholarly journals Compressive strength and microstructure of modified coffee exocarp cement-based composites

BioResources ◽  
2020 ◽  
Vol 15 (4) ◽  
pp. 9059-9074
Author(s):  
Zehua Zhu ◽  
Cheng Cheng ◽  
Debin Zhu ◽  
Dewen Liu ◽  
Yafei Zhang
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Compressive Strength ◽  
Portland Cement ◽  
Vacuum Extraction ◽  
X Ray Diffraction ◽  
Extraction Technology ◽  
X Ray ◽  
Scanning Electron

Portland cement-based composites were prepared with coffee exocarp (pretreated with water or NaOH) via vacuum extraction technology. An orthogonal test was adopted to analyze the influence of various factors on mechanical properties of the composite. The morphology and composition of the pretreated coffee exocarp and composites were analyzed via environmental scanning electron microscopy and X-ray diffraction, respectively. The results showed that the coffee exocarp content and vacuum extraction time significantly affected the compressive strength. An addition of 10% coffee exocarp had a slight negative effect on the mechanical properties but enhanced the crack inhibition and overall toughness of the composite. The scanning electron microscopy and X-ray diffraction results showed that the composite containing coffee exocarp pretreated with 4% NaOH solution had the highest density and exhibited the best properties due to mechanical interlocking between the coffee exocarp and cement. After 28 d of curing, the composites exhibited a maximum compressive strength of 15.72 MPa, a mass that was approximately 37% less than that of ordinary Portland cement samples, and a bulk density of 1.5 g/cm3 to 1.6 g/cm3. Hence, the produced biocomposites could be used for low-load pavements, providing a new type of economical building material.

scholarly journals Structural analysis of a Nb-based alloy for biomedical application

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
JR. Severino Martins Jr ◽  
CR. Grandini
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Crystalline Structure ◽  
Melting Furnace ◽  
The Body ◽  
Body Centered Cubic ◽  
X Ray Diffraction ◽  
Toxic Response ◽  
X Ray ◽  
Scanning Electron

The purpose of research in the biomaterials field is to produce new materials with physical and chemical properties close to the tissue to be replaced with minimal toxic response to the foreign body. Among the various metallic materials, titanium and its alloys have this great combination of properties. The most promising alloys are those with niobium, molybdenum, tantalum, and zirconium as alloying elements added to titanium. Thus, this kind of alloys integrate a new class of alloys without aluminum and vanadium (which cause cytotoxicity) and have a low modulus of elasticity (below 100 GPa). The objective of this work is to analyze the structure and microstructure of a niobium-based alloy, Ti-50wt%Nb. This alloy was produced in an arc-melting furnace with an inert atmosphere of argon gas. After melting, the samples were characterized by density, X-ray diffraction, scanning electron microscopy, and hardness. The X-ray diffraction data shows the peaks corresponding to the beta phase (with body-centered cubic crystalline structure), corroborated by scanning electron microscopy images. The value of the lattice parameter of the body-centered cubic crystalline structure was 3.2868 Å.  

Preparation of β-TCP/HAP Composite Bioceramics

2007 ◽  
Vol 336-338 ◽  
pp. 1642-1645 ◽  
Author(s):  
Tong Jun Liu ◽  
De An Yang ◽  
Li Zhi Di
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Compressive Strength ◽  
Phase Transformation ◽  
Composite Ceramics ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron

The β-TCP granules with the range of diameter from 314μm to 800μm were prepared. The β-TCP/HAP composite bioceramics were prepared by dipping β-TCP discs made from the granules in HAP sol. The component and morphology of the ceramics were observed by X-ray diffraction (XRD) and scanning electron microscopy (SEM) respectively. The compressive strength of specimens was tested by Testometric M350-20KN. The results show that the samples can be calcined at 1150°C without phase transformation of β-TCP to α-TCP by doping the β-TCP with 1wt% MgO. And the compressive strength of the composite ceramics reaches 24MPa.

Identification of calcium oxalate crystals in dried or fixed tobacco leaf

1984 ◽  
Vol 42 ◽  
pp. 288-289
Author(s):  
Vicki L. Baliga ◽  
Mary Ellen Counts
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Calcium Oxalate ◽  
Growth And Development ◽  
Polarized Light ◽  
Calcium Oxalate Crystals ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Electron

Calcium is an important element in the growth and development of plants and one form of calcium is calcium oxalate. Calcium oxalate has been found in leaf seed, stem material plant tissue culture, fungi and lichen using one or more of the following methods—polarized light microscopy (PLM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and x-ray diffraction.Two methods are presented here for qualitatively estimating calcium oxalate in dried or fixed tobacco (Nicotiana) leaf from different stalk positions using PLM. SEM, coupled with energy dispersive x-ray spectrometry (EDS), and powder x-ray diffraction were used to verify that the crystals observed in the dried leaf with PLM were calcium oxalate.

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