Stabilization of Cr-rich tannery waste in fly ash matrices

In the present work, the stabilization/solidification of a Cr-rich ash obtained from the anoxic incineration of tannery hazardous wastes was studied. Chromium in the starting waste was exclusively in amorphous form and in trivalent state. The waste was embedded in fly ash-based cementitious material matrices. Calcium and sodium hydroxides, as well as sodium silicate, were used as activators. The proposed process combines mechanical activation with hydrothermal curing. Successful immobilization of chromium was achieved, as attested by standard leaching tests. Backscattered electron images revealed the existence of the C-S-H gel, and elemental mapping by energy dispersive X-ray spectroscopy showed a good interdispersion of chromate and aluminosilicate species, verifying that chromium was well distributed in the final amorphous cementitious matrix. X-ray diffraction confirmed the absence of Cr-rich crystalline phases of calcium aluminosilicates, where chromium can enter in hexavalent state. The stiffness of the stabilized samples was reduced with increasing the amount of added Cr-rich ash, as attested by measurements of the dynamic Young’s modulus.

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Behavior of metallic trace elements containing in stabilized and solidified oily petroleum sludge

Nova Biotechnologica et Chimica ◽

10.2478/nbec-2019-0018 ◽

2019 ◽

Vol 18 (2) ◽

pp. 154-165

Author(s):

Dihia Bellache ◽

Karim Moussaceb ◽

Emmanuel Jousseinn ◽

Jean-Claude Bollinger ◽

Loubna Chaabane

Keyword(s):

Chemical Elements ◽

Cementitious Material ◽

Leaching Tests ◽

Acid Neutralization ◽

X Ray Diffraction ◽

X Ray ◽

Neutralization Capacity ◽

Acid Neutralization Capacity ◽

Metallic Trace Elements ◽

Edx Analyses

Abstract The present work examines the influence of the leaching conditions on the release of various chemical elements from a cementitious material obtained by solidification of an industrial waste rejection of Algeria. Toxicity Characteristic Leaching Procedure (TCLP), X-ray diffraction (XRD) and Scanning electron microscopy coupled with energy dispersive X-ray microanalysis SEM-EDX analyses were employed to characterize the waste and the stabilized/solidified materials. Than several formulations were prepared with different percent of waste ranging from 0 % to 30 %. To evaluate the influence of leaching conditions on the release of chemical ions (Zn2+, Pb2+, Cl-, Mg2+, Ca2+, Na+, K+ and SO42−) contained in the stabilized and solidified materials, the Acid Neutralization Capacity (ANC), the Pore Water (PW) and Monolith Leaching Tests (MLT) have been carried out. The leaching tests (ANC, PW and MLT) have shown a low metal leachability. However, the lowest released amount was observed for the MLT.

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Texture measurements in Al2O3 using BEKP

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100170773 ◽

1994 ◽

Vol 52 ◽

pp. 608-609

Author(s):

M. D. Vaudin ◽

J. P. Cline

Keyword(s):

Neutron Diffraction ◽

Rapid Method ◽

Crystallographic Orientation ◽

Specimen Surface ◽

X Ray Diffraction ◽

Anisotropic Crystal ◽

X Ray ◽

Verification Method ◽

Crystal Properties ◽

Backscattered Electron

The study of preferred crystallographic orientation (texture) in ceramics is assuming greater importance as their anisotropic crystal properties are being used to advantage in an increasing number of applications. The quantification of texture by a reliable and rapid method is required. Analysis of backscattered electron Kikuchi patterns (BEKPs) can be used to provide the crystallographic orientation of as many grains as time and resources allow. The technique is relatively slow, particularly for noncubic materials, but the data are more accurate than any comparable technique when a sufficient number of grains are analyzed. Thus, BEKP is well-suited as a verification method for data obtained in faster ways, such as x-ray or neutron diffraction. We have compared texture data obtained using BEKP, x-ray diffraction and neutron diffraction. Alumina specimens displaying differing levels of axisymmetric (0001) texture normal to the specimen surface were investigated.BEKP patterns were obtained from about a hundred grains selected at random in each specimen.

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Physical and Mechanical Properties of Cement Paste Were Used Partially with Fly Ash and Kaolin Waste

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.866.199 ◽

2017 ◽

Vol 866 ◽

pp. 199-203

Author(s):

Chidchanok Chainej ◽

Suparut Narksitipan ◽

Nittaya Jaitanong

Keyword(s):

Mechanical Properties ◽

Fly Ash ◽

Room Temperature ◽

Physical And Mechanical Properties ◽

Partial Replacement ◽

X Ray Diffraction ◽

X Ray ◽

Lime Water ◽

Diffraction Patterns ◽

Iron Mold

The aims of this research were study the microstructures and mechanical properties for partial replacement of cement with Fly ash (FA) and kaolin waste (KW). Ordinary Portland cement were partially replaced with FA and KW in the range of 25-35% and 10-25% by weight of cement powder. The kaolin waste was ground for 180 minutes before using. The specimen was packing into an iron mold which sample size of 5×5×5 cm3. Then, the specimens were kept at room temperature for 24 hours and were moist cured in the incubation lime water bath at age of 3 days. After that the specimens were dry cured with plastic wrap at age of 3, 7, 14 and 28 days. After that the compounds were examined by x-ray diffraction patterns (XRD) and the microstructures were examined by scanning electron microscopy (SEM). The compressive strength was then investigated.

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Monitoring of Fluctuations in the Physical and Chemical Properties of a High-Calcium Fly Ash

MRS Proceedings ◽

10.1557/proc-113-107 ◽

1987 ◽

Vol 113 ◽

Cited By ~ 8

Author(s):

Scott Schlorholtz ◽

Ken Bergeson ◽

Turgut Demirel

Keyword(s):

Fly Ash ◽

Chemical Properties ◽

Operating Conditions ◽

Physical And Chemical Properties ◽

X Ray Diffraction ◽

X Ray ◽

Morphological Studies ◽

High Calcium ◽

Physical And Chemical ◽

And Chemical Properties

ABSTRACTThe physical and chemical properties of fly ash produced at Ottumwa Generating Station have been monitored since April, 1985. The fly ash is produced from burning a low sulfur, sub-bituminous coal obtained from the Powder River Basin near Gillette, Wyoming. One-hundred and sixty samples of fly ash were obtained during the two year period. All of the samples were subjected to physical testing as specified by ASTM C 311. About one-hundred of the samples were also subjected to a series of tests designed to monitor the self-cementing properties of the fly ash. Many of the fly ash samples were subjected to x-ray diffraction and fluorescence analysis to define the mineralogical and chemical composition of the bulk fly ash as a function of sampling date. Hydration products in selected hardened fly ash pastes, were studied by x-ray diffraction and scanning electron microscopy. The studies indicated that power plant operating conditions influenced the compressive strength of the fly ash paste specimens. Mineralogical and morphological studies of the fly ash pastes indicated that stratlingite formation occurred in the highstrength specimens, while ettringite was the major hydration product evident in the low-strength specimens.

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Characterization of Fly Ash Generated from Matla Power Station in Mpumalanga, South Africa

E-Journal of Chemistry ◽

10.1155/2012/451801 ◽

2012 ◽

Vol 9 (4) ◽

pp. 1788-1795 ◽

Cited By ~ 13

Author(s):

Olushola S. Ayanda ◽

Olalekan S. Fatoki ◽

Folahan A. Adekola ◽

Bhekumusa J. Ximba

Keyword(s):

Fly Ash ◽

Inductively Coupled Plasma ◽

Coal Fly Ash ◽

Harmful Effect ◽

Point Of Zero Charge ◽

X Ray Diffraction ◽

Power Station ◽

X Ray ◽

Inductively Coupled ◽

Plasma Mass Spectrometry

In this study, fly ash was obtained from Matla power station and the physicochemical properties investigated. The fly ash was characterized by x-ray fluorescence, x-ray diffraction, scanning electron microscopy, and inductively coupled plasma mass spectrometry. Surface area, particle size, ash and carbon contents, pH, and point of zero charge were also measured. The results showed that the fly ash is alkaline and consists mainly of mullite (Al6Si2O13) and quartz (SiO2). Highly toxic metals As, Sb, Cd, Cr, and Pb as well as metals that are essential to health in trace amounts were also present. The storage and disposal of coal fly ash can thus lead to the release of leached metals into soils, surface and ground waters, find way into the ecological systems and then cause harmful effect to man and its environments.

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

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.325.181 ◽

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.

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Effect of Fly Ash and Slag on the Resistance to H2S Attack of Oil Well Cement

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.79-82.71 ◽

2009 ◽

Vol 79-82 ◽

pp. 71-74

Author(s):

Qi Wang ◽

Lin Qiao ◽

Peng Song

Keyword(s):

Fly Ash ◽

Compression Strength ◽

Blended Cement ◽

Oil Well ◽

X Ray Diffraction ◽

X Ray ◽

Curing Period ◽

Oil Well Cement ◽

Xrd Patterns ◽

Well Cement

In this paper, the resistance to H2S attack of pastes made from slag-fly ash blended cement used in oil well (SFAOW) was studied, in which fly ash (FA) was used at replacement dosages of 30% to 60% by weight of slag. Samples of SCOW and SFAOW pastes were demoulded and cured by immersion in fresh water with 2 Mp H2S insulfflation under 130oC for 15 days. After this curing period, compression strength and permeability of the samples were investigated. The reaction mechanisms of H2S with the paste were carried out through a microstructure study, which included the use of x-ray diffraction (XRD) patterns and scanning electron microscope (SEM). Based on the obtained data in this study, incorporation of FA into SCOW results in the comparable effects in the resistance to H2S attack. When the replacement dosage of slag is about 40%, the paste exhibits the best performance on resistance to H2S attack with compression strength 36.58Mp.

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Influence of Mineral Admixtures on Corrosion Inhibition Effect of Nitrites

International Journal of Corrosion ◽

10.1155/2018/2537634 ◽

2018 ◽

Vol 2018 ◽

pp. 1-6 ◽

Cited By ~ 1

Author(s):

Mengna Yang ◽

Junzhe Liu ◽

Hui Wang ◽

Yushun Li ◽

Yanhua Dai ◽

...

Keyword(s):

Fly Ash ◽

Corrosion Inhibition ◽

Ion Concentration ◽

Mineral Admixtures ◽

X Ray Diffraction ◽

Nitrite Ion ◽

X Ray ◽

Inhibition Effect ◽

Diffraction Patterns ◽

Micro Analysis

Chemical quantitative analysis of effective anticorrosion component and micro-analysis of hydration products of fly ash and slag on the influence of the nitrites corrosion inhibition was studied by the free nitrite ion concentration and X-ray diffraction pattern. The free nitrite ion concentration was used to describe the corrosion inhibition effect of nitrites. And the X-ray diffraction patterns were used to analyze the adsorption properties. The research results show that fly ash and slag were beneficial for improving the corrosion inhibition effect of nitrites. Cement-based materials with slag at low content presented high free nitrite ion concentration, but the addition of low content of fly ash harmed the corrosion inhibition effect of nitrites. The specimens incorporated with both fly ash and slag can reach the highest free nitrite ion concentration when the compounding proportion was 1:1. It was concluded that the extent of mineral admixtures of the corrosion inhibition effect of nitrites was affected by its type and content.

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STUDI TENTANG KONDUKTIVITAS DAN RESISTANSI TERMAL GEOPOLIMER BERPORI BERBASIS ABU TERBANG (FLY ASH)

Jurnal Sains dan Pendidikan Fisika ◽

10.35580/jspf.v16i2.15983 ◽

2020 ◽

Vol 16 (2) ◽

pp. 161

Author(s):

Sulfianty Sulfianty ◽

Nurhayati Nurhayati ◽

Subaer Subaer

Keyword(s):

Fly Ash ◽

X Ray Diffraction ◽

X Ray

Telah dilakukan penelitian yang bertujuan untuk menyelidiki sifat konduktivitas dan resistansi termalnya. Pembuatan sampel dengan menambahkan agen pembentuk pori (H2O2) ke dalam pasta geopolimer yang diaktivasi menggunakan alkali, dikeringkan (curing) pada suhu 70 ̊C selama 24 jam dan disimpan pada ruang terbuka selama ± 3 hari. Pengujian awal meliputi pengujian porositas, massa jenis dan daya serap air sedangkan pengujian untuk sampel geopolimer berpori sesuai standar SNI 03-0349-1989 terdiri dari X-ray Diffraction, mikroskop optik digital, konduktivitas dan resistansi termal serta resistansi api dan panas (Shock thermal). Berdasarkan hasil penelitian dapat disimpulkan bahwa penambahan H2O2 akan memperbesar porositas dan daya serap air sehingga massa jenis akan semakin kecil. Sampel yang sesuai standar SNI 03-0349-1989 berdasarkan pengujian awal adalah sampel dengan komposisi 1,6%. Hasil karakterisasi XRD menunjukan bahwa fase berbentuk amorf dengan intensitas tertinggi diperoleh oleh SiO2 dan hasil karakterisasi mikroskop optik digital menunjukan bahwa ukuran pori dari sampel tidak seragam berkisar antara 1-10 mm. Adapun hasil uji konduktivitas dan resistansi termal berturut-turut yaitu 0,77 W/m ̊K dan 0,02 K.m2/W. Serta uji resistansi api dan panas (shock thermal) menunjukan bahwa sampel dapat bertahan hingga 1300 ̊C. Hal ini menunjukan bahwa geopolimer berpori berbahan dasar abu terbang (Fly Ash) memiliki nilai konduktivitas dan resistansi termal yang rendah dan tahan terhadap suhu tinggi sehingga dapat diaplikasikan sebagai bahan isolasi termal yang baik dan ramah lingkungan.

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Alkali Fusion-Leaching Method For Comprehensive Processing Of Fly Ash

KnE Materials Science ◽

10.18502/kms.v2i2.952 ◽

2017 ◽

Vol 2 (2) ◽

pp. 89 ◽

Cited By ~ 3

Author(s):

A.A. Shoppert ◽

I.V. Loginova ◽

L.I. Chaikin ◽

D.A. Rogozhnikov

Keyword(s):

Fly Ash ◽

Power Plant ◽

X Ray Diffraction ◽

Water Leaching ◽

X Ray ◽

Comprehensive Utilization ◽

Alkali Fusion ◽

Wet Chemical ◽

Promising Source ◽

Comprehensive Processing

Fly ash, composed of mullite, hematite, amorphous silica and quartz, is a promising source for the recovery of alumina and silica. Desilication with help of NaOH and alkali fusion-leaching method and utilization of alumina and silica in the fly ash for preparation of sodalite and silica white were explored in this research. The samples were characterized by using wet chemical analysis and X-ray diffraction. The optimal extraction of SiO2 from Reftinskaya power plant fly ash was 46.2% with leaching at 95 oC for 3 h. Sodalite was synthesized at 200 °C for 1 h followed water leaching at 95 °C for 1 h. Silica white with specific surface area 180-220 m2/g was prepared by carbonation of the Na2SiO3 solution at 40 oC for 90-120 min. The as-prepared silica has a purity of 98,8%.The proposed method is suitable for the comprehensive utilization of the fly ash.

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