scholarly journals Influence of Hydrothermal Temperature on Phosphorus Recovery Efficiency of Porous Calcium Silicate Hydrate

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Wei Guan ◽  
Fangying Ji ◽  
Qingkong Chen ◽  
Peng Yan ◽  
Weiwei Zhou
Keyword(s):  
Calcium Silicate ◽  
Calcium Silicate Hydrate ◽  
Phosphorus Recovery ◽  
Limiting Factor ◽  
Recovery Efficiency ◽  
X Ray Diffraction ◽  
Hydrothermal Temperature ◽  
X Ray ◽  
Recovery Performance ◽  
Scanning Electron

Porous calcium silicate hydrate (PCSH) was synthesized by carbide residue and white carbon black. The influence of hydrothermal temperature on phosphorus recovery efficiency was investigated by Field Emission Scanning Electron Microscopy (FESEM), Brunauer-Emmett-Teller (BET), and X-Ray Diffraction (XRD). Hydrothermal temperature exerted significant influence on phosphorus recovery performance of PCSH. Hydrothermal temperature 170°C for PCSH was more proper to recover phosphorus. PCSH could recover phosphorus with content of 18.51%. The law of Ca2+and OH−release was the key of phosphorus recovery efficiency, and this law depended upon the microstructure of PCSH. When the temperature of synthesis reached to 170°C, the reactions between CaO and amorphous SiO2were more efficient. Solubility of SiO2was a limiting factor.

Synthesis of Ca(OH)2 Nanoparticles Aqueous Suspensions and Interaction with Silica Fume

2012 ◽  
Vol 629 ◽  
pp. 482-487 ◽  
Author(s):  
V. Daniele ◽  
G. Taglieri ◽  
A. Gregori
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Silica Fume ◽  
Calcium Silicate Hydrate ◽  
Thermal Analyses ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hydrate Phase ◽  
Work Interaction ◽  
Scanning Electron

In this work, interaction at ambient temperature between silica fume and artificially produced Ca(OH)2 nanoparticles by two different methods was analyzed. Initial products and formed hydrated phases were characterized by several investigations including X-ray diffraction, thermal analyses, transmission and scanning electron microscopy. Synthesized Ca(OH)2 nanoparticles appeared regularly shaped and hexagonally plated, with side dimensions from 200nm to less than 20nm. Characterization analyses showed that, by reducing particles dimensions, calcium silicate hydrate phase formation was evident already after 7 day of hydration and a nearly complete consuming of free Ca(OH)2 after 28 days was observed. Besides, formed hydrate phases showed a highly wrinkled layer with marked crumple and rough-edge surfaces.

scholarly journals Different Setting Conditions Affect Surface Characteristics and Microhardness of Calcium Silicate-Based Sealers

Scanning ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Dong-Kyu Yang ◽  
Sunil Kim ◽  
Jeong-Won Park ◽  
Euiseong Kim ◽  
Su-Jung Shin
Keyword(s):  
Calcium Silicate ◽  
Detrimental Effect ◽  
Surface Characteristics ◽  
Storage Conditions ◽  
Acid Solutions ◽  
X Ray Diffraction ◽  
Surface Microhardness ◽  
X Ray ◽  
Phosphate Buffered Saline ◽  
Scanning Electron

Objective. To investigate the effect of different setting conditions on surface microhardness and setting properties of calcium silicate-based sealers. Methods. Three sealers, EndoSequence Bioceramic (BC; Brasseler USA, Savannah, GA, USA), Endoseal MTA (ES; Maruchi, Wonju, Korea), and Well-Root ST (WR; Vericom, Chuncheon, Korea), were compared. Specimens were exposed to either butyric acid (pH 5.4) or phosphate-buffered saline (PBS [pH 7.4]) for 48 h and stored at 100% humidity for 12 days. The control specimens were stored at 100% humidity for 14 days. Surface microhardness was measured, topographic changes were observed, and phase analysis was performed using X-ray diffraction. Microhardness according to storage conditions was compared using one-way analysis of variance and Tukey’s multiple comparison tests (P<.05). Results. The BC and ES sealers exhibited decreased microhardness when stored in acid or PBS compared with control (P<.05). In the WR group, acid exposure lowered microhardness of the specimens compared with control (P<.05). Scanning electron microscopy revealed different topographies in specimens from all tested sealers exposed to acid or PBS. Conclusion. The surface microhardness of calcium silicate-based sealers was reduced by exposure to either acid or PBS. Acid solutions, however, had a more detrimental effect than PBS.

scholarly journals EFFECT OF HYDROTHERMAL TEMPERATURE ON SYNTHESIS OF HYDROXYAPATITE FROM LIMESTONE VIA HYDROTHERMAL METHOD

2018 ◽  
Vol 10 (1) ◽  
pp. 136 ◽  
Author(s):  
Novesar Jamarun ◽  
Asregi Asril ◽  
Zulhadjri Zilfa ◽  
Upita Septiani
Keyword(s):  
Hydrothermal Method ◽  
Crystal Size ◽  
Spherical Shape ◽  
X Ray Diffraction ◽  
Hydrogen Phosphate ◽  
Hydrothermal Temperature ◽  
X Ray ◽  
Nano Powder ◽  
Diammonium Hydrogen ◽  
Scanning Electron

Objective: In this study, the effect of hydrothermal temperature on the synthesis of hydroxyapatite (HAp) from limestone was investigated.Methods: Precursors of limestone (CaCO3) and diammonium hydrogen phosphate ((NH4)2HPO4) with Ca/P ratio of 1.67 was mixed at pH 10 in order to synthesize hydroxyapatite by hydrothermal method. The solution was hydrothermally treated in an autoclave at various temperatures of 120, 160 and 200 °C for 24 h. Nano powder formed was then characterized.Results: The hydroxyapatite obtained by hydrothermal method at various temperatures was characterized. The analysis of Fourier Transform Infrared (FTIR) revealed that HAp had phosphate (PO43-) and hydroxyl (O-H) groups although carbonate (CO32-) group remained. X-Ray Diffraction (XRD) revealed that the size of nanosize crystals was formed and then provided a large surface area. Scanning Electron Microscopy (SEM) results showed that HAp had a spherical shape. There was more agglomeration at 200 °C than at 160 °C. The ratio of the results of Energy Dispersive X-ray (EDX) analysis in 160 °C was 1.95 and at 200 °C was 1.71Conclusion: The hydroxyapatite prepared at a temperature of 200 °C had smaller crystal size than the hydroxyapatite prepared at the temperatures of 120 and 160 °C. SEM pictures showed that the nanoparticle hydroxyapatite had a spherical shape.

Modified xonotlite–type calcium silicate hydrate slabs for fire doors

2018 ◽  
Vol 36 (2) ◽  
pp. 83-96 ◽  
Author(s):  
Rimantas Levinskas ◽  
Irena Lukošiūtė ◽  
Arūnas Baltušnikas ◽  
Algirdas Kuoga ◽  
Aldona Luobikienė ◽  
...  
Keyword(s):  
Thermal Shock ◽  
Calcium Silicate ◽  
Calcium Silicate Hydrate ◽  
Solar Furnace ◽  
Liquid Sodium ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Surface Areas ◽  
Back Door

Xonotlite-type calcium silicate hydrate slabs were examined under the thermal shock conditions in a solar furnace at the Plataforma Solar de Almeria which can reach a peak of 300 W/cm2. We have studied the original slabs as well as those modified with a mixture of liquid sodium silicate including montmorillonite as thermal insulation materials for fire doors applications. The slabs were kept at 950°C for 1 h. We performed X-ray diffraction, thermogravimetry and differential scanning calorimetry analysis, scanning electron microscopy, Fourier transform infrared spectroscopy, and thermal conductivity measurements and determined N2 adsorption/desorption isotherms. X-ray diffraction shows that during the thermal shock at 950°C xonotlite is converted to wollastonite. Specific surface areas of xonotlite slabs decrease due to release of crystalline water molecules. It is possible to maintain temperatures of the back door not exceeding 70°C while the front door is subjected to 950°C for 1-h time periods. The standard requires no more than 140°C at the back door.

Preparation and phosphorus recovery performance of porous calcium–silicate–hydrate

2013 ◽  
Vol 39 (2) ◽  
pp. 1385-1391 ◽  
Author(s):  
Wei Guan ◽  
Fangying Ji ◽  
Qingkong Chen ◽  
Peng Yan ◽  
Qian Zhang
Keyword(s):  
Calcium Silicate ◽  
Calcium Silicate Hydrate ◽  
Phosphorus Recovery ◽  
Recovery Performance

Synthesis of Calcium Silicate Hydrate Compounds From Wet Flue Gas Desulfurization (FGD) Waste

2020 ◽  
Vol 1 (2) ◽  
pp. 88-95
Author(s):  
Denise Alves Fungaro ◽  
Lucas Caetano Grosche ◽  
Juliana de Carvalho Izidoro
Keyword(s):  
Adsorption Capacity ◽  
Flue Gas ◽  
Calcium Silicate ◽  
Calcium Silicate Hydrate ◽  
Flue Gas Desulfurization ◽  
Maximum Adsorption Capacity ◽  
Fusion Temperature ◽  
Hydrothermal Temperature ◽  
X Ray ◽  
Wide Range

In this study Calcium silicate hydrate based products (CSHP) were synthesized from wet flue gas desulfurization waste (FGD) by alkali fusion followed by hydrothermal treatment. The effect of various factors on the formation of products, such as mineralizing agent, fusion temperature and time, crystallization time and addition of Ca and Si were studied as well as the conditions optimized. The FGD and synthesized materials were characterized by using X-Ray (XRD), Scanning Electron Microscope (SEM), X-ray fluorescence (XFR), among other methods. A fusion temperature of 600 °C with NaOH, fusion duration of 1 h, and a subsequent hydrothermal temperature of 100 °C for a reaction of 24 h were found to be the optimal conditions. In these synthesis conditions, CSHP containing tobermorite and Al-tobermorite was the major phases. The synthesized CSHP revealed high selective uptake for Cs+ in water. The maximum adsorption capacity of Cs+ onto the synthesized material, as calculated from the Langmuir model, was 1949 µmol g-1. The performance on the Cs+ removal in the presence of high Na+ contents was also evaluated. The adsorbent material showed a high Cs+ adsorption capacity in deionized water and a decrease of 56% and 62% in saturated media with the Na+ ions and seawater, respectively. Therefore, CSHP as a higher value-added product can be obtained from a by-product of a coal-fired power plant, which has wide range applications, including for Cs+ removal from wastewater.

Multifractal Analysis of Calcium Silicate Hydrate (C-S-H) Mapped by X-ray Diffraction Microtomography

2012 ◽  
Vol 95 (8) ◽  
pp. 2647-2652 ◽  
Author(s):  
Luca Valentini ◽  
Gilberto Artioli ◽  
Marco Voltolini ◽  
Maria Chiara Dalconi
Keyword(s):  
Calcium Silicate ◽  
Multifractal Analysis ◽  
Calcium Silicate Hydrate ◽  
X Ray Diffraction ◽  
X Ray

Preparation of Nano-Sized Wollastonite Using Calcium Silicate Residue of Potassium Feldspar after Extraction of Potassium and Alumina

2014 ◽  
Vol 633 ◽  
pp. 35-38 ◽  
Author(s):  
Jian Chen ◽  
Jing Yang ◽  
Hong Wen Ma
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Particle Size ◽  
Calcium Silicate ◽  
Potassium Feldspar ◽  
X Ray Diffraction ◽  
X Ray ◽  
Calcined Temperature ◽  
Orientation Growth ◽  
Scanning Electron

In this paper, wollastonite nanopowder were successfully synthesized by the surfactants modified-calcined method using calcium silicate residue of potassium feldspar after extraction of potassium and alumina. The effects of modifier and calcined temperature on the phase composition, morphology and microstructure were studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results showed that the phase of samples with different modifier processing is wollastonite-2M, while CTAB as modifier can avoid preferred orientation growth. The obtained wollastonite powder is spherical in morphology and well dispersed with the particle size of approximately 150nm.

The Effect of Temperature and Time on the Formation of TiO2 (B) Nanowires via Hydrothermal Method

2018 ◽  
Vol 280 ◽  
pp. 15-20
Author(s):  
Thida San Nwe ◽  
Matthana Khangkhamano ◽  
Lek Sikong ◽  
Kalayanee Kooptanond
Keyword(s):  
Phase Composition ◽  
Reaction Time ◽  
Hydrothermal Synthesis ◽  
Effect Of Temperature ◽  
Phase Identification ◽  
X Ray Diffraction ◽  
Hydrothermal Temperature ◽  
X Ray ◽  
Higher Temperature ◽  
Scanning Electron

TiO2(B) nanowires were prepared at 170 °C, 200 °C and 220 °C for 24 h via hydrothermal synthesis to evaluate the effect of temperature on phase composition and morphologies. The effect of reaction time: 24 and 72 h on the formation was also studied at 170 °C. All samples were calcined in air at 400 °C for 2 h. Phase identification was performed using X-ray diffraction (XRD) and morphologies was examined by a scanning electron microscope (SEM). It was found that hydrothermal temperature and time played an important role in defining TiO2phase composition and its morphology. For 24 h hydrothermal synthesis, at low temperature of 170 °C, anatase TiO2nanoparticles were formed, while at higher temperature of 200 and 220 °C, TiO2(B) nanowires with averaged diameter of 49 nm and several micrometers in length were produced. Interestingly at 170 °C, by increasing reaction time to 72 h, anatase TiO2nanoparticles were completely transformed to TiO2(B) nanowires with averaged diameter of 74 nm and 2-4 micrometers in length.

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