scholarly journals Synthesis and Characterization of Mullites From Silicoaluminous Fly Ash Waste

2020 ◽  
Vol 5 (1) ◽  
pp. 10-25
Author(s):  
Virendra K. Yadav ◽  
Pallavi Saxena ◽  
Chagan Lal ◽  
Govindhan Gnanamoorthy ◽  
Nisha Choudhary ◽  
...  
Keyword(s):  
Fly Ash ◽  
Hydrofluoric Acid ◽  
Room Temperature ◽  
Major Elements ◽  
Ash Ponds ◽  
Mineral Acids ◽  
Simple Step ◽  
Hazardous Pollutants ◽  
Mullite Powder

Fly ash is considered one of the major hazardous pollutants around the globe. Every year a million tonnes of fly ash is disposed of into the fly ash ponds which are major sites of pollution. The major fractions of fly ash are silicates, aluminates, and ferrous substances followed by minor traces element oxides. The aluminates and silicates comprise of 70% of the fly ash. The aluminates and silicates are present in fly ash in the form of crystalline mullites and sillimanites. Mullites being inert and crystalline are retractile to mineral acids. So, here the authors have reported a novel and simple step for the recovery of all the major elements of fly ash along with recovery of mullites by using hydrofluoric acid at room temperature. The method comprises of treatment of fly ash with diluted hydrofluoric acid for 12 hours under agitation. The recovered white color mullite powder, rod shaped of size 90-300 nm, was analyzed by the sophisticated instruments for the confirmation of the mullite particles.

scholarly journals Characterization and compressive strength of fly ash based-geopolymer paste

2018 ◽  
Vol 195 ◽  
pp. 01023 ◽  
Author(s):  
Ari Widayanti ◽  
Ria Asih Aryani Soemitro ◽  
Hitapriya Suprayitno ◽  
Januarti Jaya Ekaputri
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Room Temperature ◽  
Chemical Resistance ◽  
Combustion Process ◽  
Mass Ratio ◽  
Alkali Activator ◽  
Compressive Strength Test ◽  
Geopolymer Paste

Fly ash is a by-product obtained from coal combustion process. Some of the utilization of fly ash is to produce geopolymer products which have high compressive strength, fire, chemical resistance. This paper proposes fly ash from unit 1-7 Suralaya Power Plant Indonesia. The aims of this study are to obtain characterization of fly ash and mechanical properties of geopolymer paste based on variations of the alkali activator ratio. The method was based on previous research and laboratory investigation. XRF and compressive strength were analysed in this study. Alkali activator was obtained from NaOH and Na2SiO3 mixture. The ratio of Na2SiO3 to NaOH was in the range of 0.5-2.5. Geopolymer paste was casted in acrylic cylinders with a diameter of 2 cm and a height of 4 cm. The curing was conducted at room temperature until the day for the compressive strength test at 28 days. The result showed that the fly ash is classified as F class. Increasing the alkali activator ratio influenced the strength. The best composition of geopolymer paste is made with NaOH 8M, and the mass ratio of Na2SiO3 to NaOH is 2.5. This composition produced compressive strength of 98.6 MPa.

Analysis of the Ash from One Shanghai Plant Using XRD (X-Ray Diffraction)

2013 ◽  
Vol 664 ◽  
pp. 232-235
Author(s):  
Guo Xian Ma ◽  
Hai Ying Zhang
Keyword(s):  
Fly Ash ◽  
Pollution Control ◽  
Room Temperature ◽  
Thermal Characterization ◽  
Xrd Analysis ◽  
Air Pollution Control ◽  
X Ray Diffraction ◽  
X Ray ◽  
Calcium Silicates

This study aims to develop a methodology for thermal characterization of APC (air pollution control)fly ash using XRD (X-ray diffraction). It performed XRD analysis as a function of temperature between room temperature and 1200 °C. It is found that major mineralogical components of fly ash involve SiO2, CaCl2, Ca3Si2O7, Ca2SiO4–0.35H2O, Ca9Si6O21–H2O, K2Al2Si2O8–3.8H2O and AlCl3–4Al(OH)3–4H2O. Glass phases account for around 57%, which is conducive to reduction of energy in recycling of the ash. Salts decompose firstly with increase of temperature and then oxides derived from the decomposition process react with SiO2, forming silicates, calcium-silicates and aluminosilicates.

scholarly journals Treatment of Mining and Thermoelectric Waste Through the Geopolymerization Process

2021 ◽  
Vol 100 ◽  
pp. 05003
Author(s):  
Morales-Aranibar Carlos ◽  
Linares Nataniel ◽  
Soto Tolomeo ◽  
Morales-Aranibar Luis
Keyword(s):  
Fly Ash ◽  
Mine Tailings ◽  
Room Temperature ◽  
Hydroelectric Plant ◽  
Chemical Characterization ◽  
Second Stage ◽  
Pyrite Content ◽  
Two Stages ◽  
Sem Morphology

Currently, energy and extraction activities generate large amounts of highly polluting waste, so there is a need for sustainable and environmentally friendly technologies. The aim of the study is to treat mining tailings and fly ash through the process of geopolymerization. The samples studied were obtained from the Toquepala mine, Tacna and from the ENGIE-Moquegua hydroelectric plant (Peru). The methodology was based on two stages, the first characterization of Fly Ash (FA) and mine tailings (MT) by EDX chemical characterization, SEM morphology, the second was prepared mixtures of MT and FA in 10 M alkaline solution, cured in 35 days at room temperature and the characterization of the geopolymer by organoleptic analysis, SEM and TCLP. The first stage shows high aluminosilicate content 20.44% Al2O3 and 53.39 % SiO2 for (MT); 22.11% Al2O3 and 51.76% SiO2 for (FA), presents metal and pyrite content. In the second stage, the samples show health and environmental harmlessness, with the formation of tetragonal structures typical of the geopolymer, the samples show a significant reduction of Sr, Ca, Fe, Pb, Ba, Be, and Cu, demonstrating the effectiveness of treatment by means of geopolymerization opening a new field for the environmental passive treatment.

scholarly journals Synthesis and characterization of eco-friendly mortars made with RHA-NaOH activated fly ash as binder at room temperature

2021 ◽  
Vol 1 ◽  
pp. 100010
Author(s):  
Juvenal Giogetti Deutou Nemaleu ◽  
Cyriaque Rodrigue Kaze ◽  
Jordan Valdès Sontia Metekong ◽  
Adeyemi Adesina ◽  
Thamer Alomayri ◽  
...  
Keyword(s):  
Fly Ash ◽  
Room Temperature ◽  
Synthesis And Characterization

Laboratory synthesis and characterization of Knasibfite K3Na4[SiF6]3[BF4] and the homologous Ge compound K3Na4[GeF6]3[BF4]

2020 ◽  
Vol 235 (8-9) ◽  
pp. 247-254
Author(s):  
Jascha Bandemehr ◽  
Josefin Klippstein ◽  
Sergei I. Ivlev ◽  
Malte Sachs ◽  
Florian Kraus
Keyword(s):  
Crystal Structure ◽  
Phase Transition ◽  
Raman Spectra ◽  
Hydrofluoric Acid ◽  
Room Temperature ◽  
Synthesis And Characterization ◽  
Infrared And Raman Spectra ◽  
Monoclinic Structure ◽  
Laboratory Synthesis

AbstractHerein we present the synthesis, crystal structure, and the infrared and Raman spectra of K3Na4[SiF6]3[BF4]. The compound also occurs in nature as the mineral Knasibfite. We obtained it from the reaction of stoichiometric amounts of SiO2, Na[BF4], K2CO3, and Na2CO3 in hydrofluoric acid at room temperature. Hydrofluorothermal synthesis at 200 °C lead to a product of higher purity. Knasibfite is colorless and crystallizes in space group Im 2m with a = 5.546(2), b = 9.261(2), c = 17.184(4) Å, V = 882.5(4) Å3, Z = 2, at T = 400(2) K. At 342 K a phase transition to a monoclinic structure was observed (I 2, a = 5.5003(6), b = 9.0890(9), c = 17.0048(2) Å, β = 90.041(9)°, V = 852.2(2) Å3, Z = 2, T = 100(2) K). By replacing SiO2 with GeO2 as a starting material K3Na4[GeF6]3[BF4] was obtained. This compound also crystallizes in form of two polymorphs, both of which are isotypic to the respective ones of K3Na4[SiF6]3[BF4].

Characterization of intergranular cuprous oxide in polycrystalline YBa2Cu3O7-x

1988 ◽  
Vol 46 ◽  
pp. 880-881
Author(s):  
Bradley L. Thiel ◽  
Chan Han R. P. ◽  
Kurosky L. C. Hutter ◽  
I. A. Aksay ◽  
Mehmet Sarikaya
Keyword(s):  
Grain Boundary ◽  
Cuprous Oxide ◽  
Room Temperature ◽  
Boundary Phase ◽  
Spectroscopic Techniques ◽  
Transition Width ◽  
Practical Applications ◽  
Thin Foils ◽  
Superconducting Oxides

The identification of extraneous phases is important in understanding of high Tc superconducting oxides. The spectroscopic techniques commonly used in determining the origin of superconductivity (such as RAMAN, XPS, AES, and EXAFS) are surface-sensitive. Hence a grain boundary phase several nanometers thick could produce irrelevant spectroscopic results and cause erroneous conclusions. The intergranular phases present a major technological consideration for practical applications. In this communication we report the identification of a Cu2O grain boundary phase which forms during the sintering of YBa2Cu3O7-x (1:2:3 compound).Samples are prepared using a mixture of Y2O3. CuO, and BaO2 powders dispersed in ethanol for complete mixing. The pellets pressed at 20,000 psi are heated to 950°C at a rate of 5°C per min, held for 1 hr, and cooled at 1°C per min to room temperature. The samples show a Tc of 91K with a transition width of 2K. In order to prevent damage, a low temperature stage is used in milling to prepare thin foils which are then observed, using a liquid nitrogen holder, in a Philips 430T at 300 kV.

Characterization of lead-bearing phases in municipal waste combustor fly ash

1996 ◽  
Vol 54 ◽  
pp. 516-517
Author(s):  
L. L. Sutter ◽  
G. R. Dewey ◽  
J. F. Sandell
Keyword(s):  
Fly Ash ◽  
Bottom Ash ◽  
Municipal Waste ◽  
Primary Concern ◽  
Leaching Behavior ◽  
Waste Combustion ◽  
Lead And Cadmium ◽  
Lead Speciation ◽  
Accepted Practice

Municipal waste combustion typically involves both energy recovery as well as volume reduction of municipal solid waste prior to landfilling. However, due to environmental concerns, municipal waste combustion (MWC) has not been a widely accepted practice. A primary concern is the leaching behavior of MWC ash when it is stored in a landfill. The ash consists of a finely divided fly ash fraction (10% by volume) and a coarser bottom ash (90% by volume). Typically, MWC fly ash fails tests used to evaluate leaching behavior due to high amounts of soluble lead and cadmium species. The focus of this study was to identify specific lead bearing phases in MWC fly ash. Detailed information regarding lead speciation is necessary to completely understand the leaching behavior of MWC ash.

scholarly journals Synthesis and characterization of a new ZIF-67@MgAl2O4 nanocomposite and its adsorption behaviour

RSC Advances ◽  
2021 ◽  
Vol 11 (22) ◽  
pp. 13245-13255
Author(s):  
Mehdi Davoodi ◽  
Fatemeh Davar ◽  
Mohammad R. Rezayat ◽  
Mohammad T. Jafari ◽  
Mehdi Bazarganipour ◽  
...  
Keyword(s):  
Room Temperature ◽  
Magnesium Aluminate ◽  
Synthesis And Characterization ◽  
Magnesium Aluminate Spinel ◽  
Adsorption Behaviour ◽  
Zeolitic Imidazolate Framework ◽  
Simple Method

New nanocomposite of zeolitic imidazolate framework-67@magnesium aluminate spinel (ZIF-67@MgAl2O4) has been fabricated by a simple method at room temperature with different weight ratios.

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