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Journal Articles

Calcium silicate hydrate (C-S-H) gel solubility data and a discrete solid phase model at 25 $^{circ}$ C based on two binary non-ideal solid solutions

Walker, C.; Suto, Shunkichi; Oda, Chie; Mihara, Morihiro; Honda, Akira

Cement and Concrete Research, 79, p.1 - 30, 2016/01

https://doi.org/10.1016/j.cemconres.2015.07.006

Times Cited Count：69 Percentile：90.42(Construction & Building Technology)

Modeling the solubility behavior of calcium silicate hydrate (C-S-H) gel is important to make quantitative predictions of the degradation of hydrated ordinary Portland cement (OPC) based materials. Experimental C-S-H gel solubility data have been compiled from the literature, critically evaluated and supplemented with new data from the current study for molar Ca/Si ratios = 0.2-0.83. All these data have been used to derive a discrete solid phase (DSP) type C-S-H gel solubility model based on two binary non-ideal solid solutions in aqueous solution(SSAS). Features of the DSP type C-S-H gel solubility model include satisfactory predictions of pH values and Ca and Si concentrations for all molar Ca/Si ratios = 2.7 0 in the C-S-H system, portlandite (CH) for Ca/Si ratios 1.65, congruent dissolution at Ca/Si ratios = 0.85, and amorphous silica (SiO $_{2 (rm am)}$ ) for Ca/Si ratios 0.55 as identified in the current study by IR spectroscopy.

JAEA Reports

Study of assessing aqueous reprocessing process for the pipeless reprocessing plant

*; *; Fumoto, Hiromichi*; *; *

JNC TJ9400 2000-001, 112 Pages, 2000/02

JNC-TJ9400-2000-001.pdf:6.67MB

The purpose of this study is to investigate the possibility of new reprocessing process for the purpose of introducing pipeless plant concept, where aqueous separation methods other than solvent extraction method are adopted in order to develop more economical FBR fuel (MOX fuel) reprocessing process. At it's first stage, literature survey on precipitation method, crystallization method and ion-exchange method was performed. Based on the results, following processes were candidated for pipeless reprocessing plant. (1)The process adopting crystallization method and peroxide precipitation method (2)The process adopting oxalate precipitation method (3)The process under mild aqueous conditions (crystallization method and precipitation method) (4)The process adopting crystallization method and ion-exchange method (5)The process adopting crystallization method and solvent extraction method The processes (1)(5) were compared with each others in terms of competitiveness to the conventional reference process, and merits and demerits were evaluated from the viewpoint of applicability to pipeless reprocessing plant, safety, economy, Efficiencies in consumption of Resources, non-proliferation, and, Operation and Maintenance. As a result, (1)The process adopting crystallization method and peroxide precipitation method was selected as the most reasonable process to pipeless plant. Preliminary criticality safety analyses, main process chemical flowsheet, main equipment list and layout of mobile vessels and stations were reported for the (1) process.