Influence of Variation (Ca-Mg)/Al Molar Ratios on Phase Composition of Ca-Mg-Al Hydrotalcite

2014 ◽  
Vol 1 (1) ◽  
Keyword(s):  
Phase Composition ◽  
Molar Ratios

Nano-Crystalline Barium Hexaferrite Powders Prepared by Mechanical Alloying Using Acetate Precursor

2008 ◽  
Vol 368-372 ◽  
pp. 610-612 ◽  
Author(s):  
M. Honarvar Nazari ◽  
Abolghasem Ataie ◽  
S.A. Seyyed Ebrahimi
Keyword(s):  
Heat Treatment ◽  
Magnetic Properties ◽  
Phase Composition ◽  
Mechanical Alloying ◽  
Thermal Behavior ◽  
Crystallite Size ◽  
Barium Hexaferrite ◽  
Subsequent Heat Treatment ◽  
Molar Ratios ◽  
Nano Crystalline

Nano-crystalline barium hexaferrite powders have been prepared by mechanical alloying of nFe2O3+Ba(CH3COO)2 with Fe/Ba molar ratios of 10-12 and subsequent heat treatment. Thermal behavior, phase composition, morphology and magnetic properties of samples were studied using DTA/TGA, XRD, SEM and VSM, respectively. Nano-crystalline Ba-hexaferrite with a mean crystallite size of 46 nm and magnetic properties as high as Ms = 73.9 A.m2/kg and Hci = 334.2 kA/m was formed for mixture of 5.5Fe2O3+Ba(CH3COO)2 which was milled for 48 h and then annealed at 1100 °C.

Effect of variation Mn/W molar ratios on phase composition, morphology and optical properties of MnWO4

2013 ◽  
Vol 39 (5) ◽  
pp. 5159-5163 ◽  
Author(s):  
Sen Zhou ◽  
Jianfeng Huang ◽  
Ting Zhang ◽  
Haibo Ouyang ◽  
Ating Li ◽  
...  
Keyword(s):  
Optical Properties ◽  
Phase Composition ◽  
Molar Ratios

scholarly journals Effects of Si/Al Ratios on the Bulk-Type Zeolite Formation Using Synthetic Metakaolin-Based Geopolymer with Designated Composition

Crystals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1310
Author(s):  
Guoru Ma ◽  
Chengying Bai ◽  
Meirong Wang ◽  
Peigang He
Keyword(s):  
Phase Composition ◽  
Hydrothermal Treatment ◽  
Hydrothermal Process ◽  
Molar Ratios ◽  
Zeolite Formation ◽  
Fixed Composition ◽  
Type Zeolite ◽  
Influence Of Impurities ◽  
Geopolymer Composites

In this paper, synthetic metakaolin with fixed composition (Al2O3·2SiO2) was produced by a simple chemosynthetic route. The chemosynthetic metakaolin can eliminate the influence of impurities in metakaolin from natural kaolin minerals. The synthetic metakaolin together with NaOH and SiO2-sol were used to prepare Na-based geopolymer precursors with various molar ratios of Si/Al. The molar ratios of Si/Al from 1 to 2 were tailored by adding different contents of SiO2-sol. Zeolite/geopolymer composites or monolith-type zeolite were successfully fabricated from synthetic metakaolin-based geopolymer through a hydrothermal process. The effects of Si/Al ratios on the phase composition and microstructure of the produced zeolite/geopolymer composites or zeolites were studied. The results proved that the composition of synthetic metakaolin and geopolymer precursors can be facilely tuned, and the monolithic geopolymer precursors can be mostly, or even totally, transformed into zeolite after hydrothermal treatment.

Preparation of aluminium ammonium calcium phosphates using microwave radiation

2013 ◽  
Vol 67 (9) ◽  
Author(s):  
Kinga Łuczka ◽  
Daniel Sibera ◽  
Aleksandra Smorowska ◽  
Barbara Grzmil
Keyword(s):  
Particle Size ◽  
Phase Composition ◽  
Microwave Radiation ◽  
Process Parameters ◽  
Calcium Phosphates ◽  
Xrd Analysis ◽  
Fractional Factorial ◽  
Molar Ratio ◽  
Influence Of Process Parameters ◽  
Molar Ratios

AbstractMicrowave radiation was used in the acquisition of aluminium ammonium calcium phosphates. The substrates such as CaCO3, H3PO4, aqueous ammonia were reagent grade, whereas Al(OH)3 was prepared afresh. The influence of process parameters (pH 6 ± 2, molar ratios of Al3+: Ca2+: PO43− in the substrates, respectively 0.31: 0.62: 1; 0.5: 0.5: 1; 0.72: 0.36: 1) on the phase composition and the product properties was determined. Statistical software STATISTICA 10 was used for planning and evaluation of the experiments. The process parameters making it possible to acquire the material with the anticipated physicochemical properties were determined based on statistical evaluation of the planned research by the plan fractional factorial design at three levels 3(k−p). The phase composition of the samples was studied using XRD analysis. The specific surface area was calculated using the BET method and the particle size was determined by LSM. Materials with a molar ratio of Al3+: Ca2+ and Al3+: NH4+ in the range of 0.07–0.76 and 0.75–3.4, respectively, with an absorption oil number of 36–56 g per 100 g, S BET within 8.2–73 m2 g−1, and particle size in the range of 156–252 nm were obtained.

Reaction of α-Fe2O3 (hematite) with potassium carbonate at elevated temperatures

1986 ◽  
Vol 51 (4) ◽  
pp. 809-818 ◽  
Author(s):  
Jaroslav Vinš ◽  
Markéta Urbanová ◽  
Jan Šubrt ◽  
Vladimír Zapletal ◽  
Aleksander A. Zakharov ◽  
...  
Keyword(s):  
Phase Composition ◽  
Powder Diffraction ◽  
Potassium Carbonate ◽  
Elevated Temperatures ◽  
X Ray ◽  
Rate Law ◽  
Molar Ratios ◽  
Cubic Structure ◽  
Diffraction Patterns ◽  
Kinetics Of

The kinetics of the reaction between α-Fe2O3 and K2CO3 have been investigated over the temperature range 600 to 800 °C, and the phase composition of the products has been determined. The reaction follows the rate law α = 1 - exp (-kτn). At molar ratios K : Fe 1, KFeO2 is the only product. At K : Fe 1, initially formed KFeO2 reacts with hematite to yield K2Fe4O7. The latter phase has been assigned a cubic structure with a = 1.681 ± 0.003 nm. based on X-ray powder diffraction patterns and Mossbauer spectra, the structure of K2Fe4O7 is proposed to be a cubic close-packed array of oxygen atoms, part of these being replaced by potassium atoms, with Fe atoms occupying the octahedral interstices.

Sign in / Sign up

Export Citation Format

Share Document