Kinetics of zeolite A crystallization

Ciric, Julius

doi:10.1016/0021-9797(68)90135-5

Cited by 113 publications

(40 citation statements)

References 6 publications

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“…Several of the kinetic data in the literature are case specific and caution must be exercised when making comparisons. Type A zeolite is usually carried out in solution synthesis and the products washed and thermally post-treated (Ciric, 1968;Hu and Lee, 1990).…”

Section: Comparison Of Hydroceramic Host Kinetics Results With Literamentioning

confidence: 99%

“…Many variables including temperature can in fact influence the crystallization of zeolite phases. Ciric (1968) (Hu and Lee, 1990). …”

Section: Comparison Of Hydroceramic Host Kinetics Results With Literamentioning

confidence: 99%

“…Several studies have been conducted to reinforce this theory (Subotic and Graovac, 1985;Bronic et al, 1987;Subotic 1989;Katovic, 1989;Subotic and Bronic, 1993). Ciric (1968) studied the kinetics of zeolite A crystallization at 100 o C by varying NaOH. Water-sorption method was used to calculate the percent of crystalline phase in search of concrete evidence to support Kerr's (1966) autocatalytic hypothesis.…”

Section: Mechanisms Of Zeolite Transformationmentioning

confidence: 99%

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Determination of the Rate of Formation of Hydroceramic Waste Forms made with INEEL Calcined Wastes

Scheetz¹,

Olanrewaju²

2001

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iii Executive SummaryA "hydroceramic" nuclear waste form, developed especially to address the immobilization of the reprocessing wastes from the Idaho National Engineering and Environmental Laboratory, has been demonstrated to possess superior chemical and mechanincal properties. Furthermore, the processing requirements of hydroceramic waste forms are simple, less costly and offer greater safety to INEEL personnel than other waste form preparation systems.The objective of this research was two fold. The initial phase of the study was to systematically survey the suitability of readily available pozzolanic additions as raw materials for hydroceramic formulations in order to identify a source material that would be compatible with the established processing requirements for the waste form i.e., no excessive water demand, proper mineralogical composition of the waste form, low leachability, waste loadings greater than 20 weight percent calcine and also readily available to INEEL in large quantities once the pozzolan(s) selection was made. Pozzolanic materials are normally finely divided substances that contain either glassy or crystalline sources of silica that are chemically reactive enough to combine with lime and water at room temperature to form cementitious material. The primary objective of the research program was to establish the final processing parameters for the preparation of hydroceramic waste forms form INEEL wastes i.e., the rate at which hydroceramic is formed, the phases that formed and the optimum temperature needed to minimize leachability.A total of 20 pozzolanic materials were surveyed. These included a number of different fly ash sample, natural and thermally altered clays, reactive aluminas and even finely ground bottle glass. The survey resulted in the selection of a natural, thermally altered clay (metakaolinite) that has found extensive use in the manufacture of blended Portland cement and currently mined in Troy Idaho.A "host" matix formulation was initially developed using Troy metakaolinite and all processing parameters and chemical and mineralogical characterization was conducted on these samples. Once developed, the host matrix was used to subsequently prepare waste forms based on fluorinel and zirconia simulated calcines supplied by INEEL. A waste loading study was conducted in order to determine the maximum loading that could be sustained and still exibit the leaching characteristics and mechanical properties of the laboratory specimens. The "host" matrix samples and the two waste forms were processed at 75, 85, 95, 125, 150, 175 and 200 o C at 100% relative humidity for times often exceeding 500 hours. Two sets of mineralogy were observed for the "host" samples and "waste loaded" samples. The waste loading study optimized the hydroceramic waste form at 30% by weight for both fluorinel and zirconia waste calcines.The hydration rate studies conducted as a function of time and temperature determined that both the "host" matrix formulation and the fluorinel and zirconia waste loaded...

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Section: Comparison Of Hydroceramic Host Kinetics Results With Literamentioning

confidence: 99%

“…Many variables including temperature can in fact influence the crystallization of zeolite phases. Ciric (1968) (Hu and Lee, 1990). …”

Section: Comparison Of Hydroceramic Host Kinetics Results With Literamentioning

confidence: 99%

Section: Mechanisms Of Zeolite Transformationmentioning

confidence: 99%

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Determination of the Rate of Formation of Hydroceramic Waste Forms made with INEEL Calcined Wastes

Scheetz¹,

Olanrewaju²

2001

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“…The ratelimiting step was the incorporation of these latter species into stable crystalline nuclei which resulted in the final zeolite product. Later in the same decade, Ciric [44] presented a very detailed study on the growth of zeolite crystals. His observations included a wide variety of techniques such as microscopy, adsorption measurements, and chemical analyses, and pointed towards a growth mechanism in which solution mediated the process with the participation of a gel phase present.…”

Section: Synthesis and Structurementioning

confidence: 99%

Ordered Porous Nanomaterials: The Merit of Small

Murcia

2013

ISRN Nanotechnology

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This paper will introduce the reader to some of the “classical” and “new” families of ordered porous materials which have arisen throughout the past decades and/or years. From what is perhaps the best-known family of zeolites, which even now to this day is under constant research, to the exciting new family of hierarchical porous materials, the number of strategies, structures, porous textures, and potential applications grows with every passing day. We will attempt to put these new families into perspective from a synthetic and applied point of view in order to give the reader as broad a perspective as possible into these exciting materials.

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“…Chemically controlled particulate properties of zeolites [13], kinetics of zeolite crystallization [14], effect of thermal and hydrothermal treatment [15], influence of anions on the kinetics of zeolite crystallization [16], growth mechanism [17], and heating methods [18,19] are the most popular aspects of zeolites which have extensively been investigated by different researchers. In spite of a large amount of experimental studies on zeolites, they have not been effectively investigated from * E-mail: behzad.vaferi@gmail.com the theoretical point of view, and mathematical simulations of their behavior have not been fully developed.…”

Section: Introductionmentioning

confidence: 99%

Prediction of degree of crystallinity for the LTA zeolite using artificial neural networks

Ghanbari

Vaferi

2017

Materials Science-Poland

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Zeolites are microporous aluminosilicate/silicate crystalline materials with three-dimensional tetrahedral configuration. In this study, the degree of crystallinity of the synthesized Linde Type A (LTA) zeolite, which is the main indicator of its quality/purity is tried to be modeled. Effect of crystallization time, temperature, molar ratio of the synthesis gel on the relative crystallinity of the LTA zeolites is investigated using artificial neural networks. Our experimental observations and some data collected from literature have been used for adjusting the parameters of the proposed model and evaluating its performance. It has been observed that two-layer perceptron network with eight hidden neurons is the most accurate approach for the considered task. The designed model predicts the experimental datasets with a mean square error of 3.99 × 10 −6 , absolute average relative deviation of 8.69 %, and regression coefficient of 0.9596. The proposed model can decrease the required time and number of experiments to evaluate the extent of crystallinity of the LTA zeolites.

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Kinetics of zeolite A crystallization

Cited by 113 publications

References 6 publications

Determination of the Rate of Formation of Hydroceramic Waste Forms made with INEEL Calcined Wastes

Determination of the Rate of Formation of Hydroceramic Waste Forms made with INEEL Calcined Wastes

Ordered Porous Nanomaterials: The Merit of Small

Prediction of degree of crystallinity for the LTA zeolite using artificial neural networks

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