Characterization of chemical properties, unit cell parameters and particle size distribution of three zeolite reference materials: RM 8850 – zeolite Y, RM 8851 – zeolite A and RM 8852 – ammonium ZSM-5 zeolite

Turner, Shirley; Sieber, John R.; Vetter, Thomas W.; Zeisler, Rolf; Marlow, Anthony F.; Moreno-Ramirez, M.G.; Davis, Mark E.; Kennedy, Gordon J.; Borghard, William G.; Yang, Shuhao; Navrotsky, Alexandra; Toby, Brian H.; Kelly, James Floyd; Fletcher, Robert A.; Windsor, Eric S.; Verkouteren, Jennifer R.; Leigh, Stefan D.

doi:10.1016/j.micromeso.2007.03.019

Cited by 27 publications

(27 citation statements)

References 35 publications

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“…Its S° and C p° were calculated based on the data of chabazite, SiO 2 , CaO, Na 2 O and zeolitic H 2 O as no measured data were available and as both the structures of zeolite Y and zeolite X are based on 6-membered rings similar to the structure of chabazite. The resulting Δ f H° of -8327 kJ/mol is lower than the Δ f H° of -8160 kJ/mol obtained by Turner et al (2008) based on high temperature calorimetry or the -8210 kJ/mol derived from the measurements of dehydrated faujasite by Petrovic and Navrotsky (1997).…”

Section: Solubility Of Chabazite Zeolite Y and Zeolite Xcontrasting

confidence: 63%

Zeolite formation in the presence of cement hydrates and albite

Lothenbach

Bernard

Mäder

2017

Physics and Chemistry of the Earth, Parts A/B/C

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Zeolite formation caused by interactions between cement hydrates and rock forming minerals was investigated by two sets of batch experiments and supported by thermodynamic modelling. The first set of batch experiments investigated the interaction between calcium silicate hydrates (C-S-H) (Ca 0.8 SiO 2.8 •32H 2 O) and ettringite (Ca 6 Al 2 (SO 4) 3 (OH) 12 (H 2 O) 26) as cement hydrate minerals and albite (NaAlSi 3 O 8) as a rock forming mineral at 20, 50 and 80°C. The dissolution of C-S-H, ettringite and albite led to relatively high calcium and low silicon and sodium concentrations and to the formation of zeolite P(Ca) (Ca 2 Al 2 Si 2 O 8 4.5H 2 O) and natrolite (Na 2 Al 2 Si 3 O 10 2H 2 O). The second set of experiments used ettringite and silica fume as cement phases and NaAlO 2 to represent a rock forming mineral. High initial sodium, hydroxide and aluminium concentrations were observed leading to the precipitation of zeolite X (Na 2 Al 2 Si 2.5 O 9 6.2H 2 O) and C-S-H gel at 20 and 50°C where only 40 to 60% of the silica had reacted after 3 years. At 80°C where more silica fume had reacted, the formation of SiO 2-rich zeolite Y (Na 2 Al 2 Si 4 O 12 8H 2 O) and chabazite (CaAl 2 Si 4 O 12 6H 2 O) was observed. Solubility products for the zeolite P(Ca), natrolite, chabazite, zeolite X and zeolite Y were obtained from the measured concentrations. Comparison with values published in the literature shows a high

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Section: Solubility Of Chabazite Zeolite Y and Zeolite Xcontrasting

confidence: 63%

Zeolite formation in the presence of cement hydrates and albite

Lothenbach

Bernard

Mäder

2017

Physics and Chemistry of the Earth, Parts A/B/C

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“…The enthalpy of formation from elements for zeolite A obtained in this study, -2738 ± 5 kJ/mol, is in excellent agreement with the value obtained by calorimetric measurements (-2731.3 ± 1.8 kJ/mol) (Turner et al 2008), and compares favorably with the value obtained by theoretical calculations (-2739 kJ/mol) (Mathieu and Viellard 2010). In these two studies, zeolite A is formulated as Na 0.5067 Al 0.501 Si 0.4974 O 1.99965 ⋅1.0906H 2 O.…”

Section: Validation Of Calculations and Discussionsupporting

confidence: 90%

A thermodynamic model for silica and aluminum in alkaline solutions with high ionic strength at elevated temperatures up to 100 C: Applications to zeolites

Xiong

2012

American Mineralogist

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In this study, a thermodynamic model for silica and aluminum in high ionic strength solutions at elevated temperatures up to 100 °C is constructed. Pitzer equations are utilized for the thermodynamic model construction. This model is valid up to ionic strengths of ∼24 molal (m) in NaOH solutions with silicate concentrations up to ∼1.5 m. The speciation of silica (including monomers and polymers) and aluminum at elevated temperatures is taken into account. Also, the equilibrium constants for silicic acid and its polymer species (H 4 SiO 4 , H 5 Si 2 O 7 -, H 4 Si 2 O 7 2-, and H 5 Si 3 O 7 3-) at elevated temperatures up to 100 °C, are obtained based on theoretical calculations. Using this thermodynamic model, thermodynamic properties, including equilibrium constants, and respective reaction enthalpies are obtained for sodium silicates, zeolite A, and the amorphous form of zeolite A, based on solubility experiments at elevated temperatures. The equilibrium constants for zeolite A and amorphous precursor of zeolite A regarding the following reactions up to 100 °C, NaAlSiO 4 ⋅2.25H 2 O(cr) + 4H + = Na + + Al 3+ + H 4 SiO 4 (aq) + 2.25H 2 O(l) (1) and NaAlSiO 4 ⋅2.25H 2 O(am) + 4H + = Na + + Al 3+ + H 4 SiO 4 (aq) + 2.25H 2 O(l) (2) can be expressed as follows K T log 7963 327 16.46 0.96 1 = ± − ± (3) and K T log 12971 160 30.80 0.50 2 = ± − ±where T is temperature in Kelvin. The enthalpy of formation from elements, Gibbs free energy of formation from elements, and standard entropy derived for zeolite A and the amorphous form of zeolite A with the chemical formulas mentioned above at 25 °C and 1 bar are -2738 ± 5 kJ/mol, -2541 ± 2 kJ/mol, 373 ± 10 J/(K⋅mol); and -2642 ± 3 kJ/mol, -2527 ± 2 kJ/mol, and 648 ± 10 J/(K⋅mol), respectively. The enthalpy of formation from elements for zeolite A derived in this study based on solubility experiments in hydrothermal solutions agrees well with those obtained by calorimetric measurements and by theoretical calculations.

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“…For the sludge precipitated with iron(II) sulfate, some hematite was also found. As can be seen in the diffractogram (see Figure 1), the prominent peaks, and, for zeolites, typical peaks 34−36 in the 2θ range of 15°–20° are absent. If zeolites are present in biosolids, they are likely to be associated with cations, such as sodium or calcium, so when biosolids are used in co-combustion, the importance of zeolites as an alkali adsorbent is probably smaller than has been suggested in previous publications.…”

Section: Resultsmentioning

confidence: 84%

Combustion of Biosolids in a Bubbling Fluidized Bed, Part 1: Main Ash-Forming Elements and Ash Distribution with a Focus on Phosphorus

et al. 2014

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This is the first in a series of three papers describing combustion of biosolids in a 5-kW bubbling fluidized bed, the ash chemistry, and possible application of the ash produced as a fertilizing agent. This part of the study aims to clarify whether the distribution of main ash forming elements from biosolids can be changed by modifying the fuel matrix, the crystalline compounds of which can be identified in the raw materials and what role the total composition may play for which compounds are formed during combustion. The biosolids were subjected to low-temperature ashing to investigate which crystalline compounds that were present in the raw materials. Combustion experiments of two different types of biosolids were conducted in a 5-kW benchscale bubbling fluidized bed at two different bed temperatures and with two different additives. The additives were chosen to investigate whether the addition of alkali (K2CO3) and alkaline-earth metal (CaCO3) would affect the speciation of phosphorus, so the molar ratios targeted in modified fuels were P:K = 1:1 and P:K:Ca = 1:1:1, respectively. After combustion the ash fractions were collected, the ash distribution was determined and the ash fractions were analyzed with regards to elemental composition (ICP-AES and SEM-EDS) and part of the bed ash was also analyzed qualitatively using XRD. There was no evidence of zeolites in the unmodified fuels, based on low-temperature ashing. During combustion, the biosolid pellets formed large bed ash particles, ash pellets, which contained most of the total ash content (54%–95% (w/w)). This ash fraction contained most of the phosphorus found in the ash and the only phosphate that was identified was a whitlockite, Ca9(K,Mg,Fe)(PO4)7, for all fuels and fuel mixtures. With the addition of potassium, cristobalite (SiO2) could no longer be identified via X-ray diffraction (XRD) in the bed ash particles and leucite (KAlSi2O6) was formed. Most of the alkaline-earth metals calcium and magnesium were also found in the bed ash. Both the formation of aluminum-containing alkali silicates and inclusion of calcium and magnesium in bed ash could assist in preventing bed agglomeration during co-combustion of biosolids with other renewable fuels in a full-scale bubbling fluidized bed.

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Characterization of chemical properties, unit cell parameters and particle size distribution of three zeolite reference materials: RM 8850 – zeolite Y, RM 8851 – zeolite A and RM 8852 – ammonium ZSM-5 zeolite

Cited by 27 publications

References 35 publications

Zeolite formation in the presence of cement hydrates and albite

Zeolite formation in the presence of cement hydrates and albite

A thermodynamic model for silica and aluminum in alkaline solutions with high ionic strength at elevated temperatures up to 100 C: Applications to zeolites

Combustion of Biosolids in a Bubbling Fluidized Bed, Part 1: Main Ash-Forming Elements and Ash Distribution with a Focus on Phosphorus

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