Processing of Titanates and Zeolites and use of a Cartridge System for ’Reactor‘ Wastes

1981 ◽  
Vol 6 ◽  
Author(s):  
S. Forberg ◽  
T. Westermark ◽  
K. Svärdströbm ◽  
L. FÄlth
Keyword(s):  
Large Scale ◽  
Hot Isostatic Pressing ◽  
Sodium Titanate ◽  
Coarse Grain ◽  
Inorganic Ion Exchangers ◽  
New Methods ◽  
Inorganic Ion ◽  
Composite Ion Exchanger ◽  
Practical Experiences ◽  
Radioactive Species

ABSTRACTNew methods were introduced in order to facilitate the production of i) very coarse-grain pure mordenite at a large scale ii) mono-disperse sodium titanate of a low price also at small volumes, and iii) a composite ion exchanger with up to 20 W-% of mordenite in beads of sodium titanate.Zeolites and titanates were converted to ceramic bodies by hot isostatic pressing at 1 300°C or by cold pressing followed by sintering at temperatures up to 1 300° C. Processed materials were zeolites, titanates and mixtures of them. The mechanical properties of sintered titanates were inferior to the hot pressed ones. Diffraction studies, static leaching at 40°C and Soxhlet leach tests were performed. The leach rates were much higher for mixed materials than for pure ones.For the handling of inorganic ion exchangers through all processes from packing of inactive beds and immobilization of radioactive species to the sintering or hot pressing for final disposal a system of cartridges is suggested. A lay-out of the system is presented together with some special arguments and some practical experiences. Simple, safe and hygienic operations with an optimal use of the inorganic sorbents are expected to result from this system.

Ceramization of Inorganic Ion Exchangers Loaded with Nuclear-Waste into Red Clay Tiles

1982 ◽  
Vol 15 ◽  
Author(s):  
Jukka Lehto ◽  
Olli J. Heinonen ◽  
Jorma K. Miettinen
Keyword(s):  
Nuclear Waste ◽  
Hot Pressing ◽  
Weight Ratio ◽  
Sodium Titanate ◽  
New Method ◽  
Ion Exchangers ◽  
Red Clay ◽  
Inorganic Ion Exchangers ◽  
Inorganic Ion ◽  
Clay Tiles

ABSTRACTA new method to ceramize inorganic ion exchangers loaded with nuclear waste has been developed. It is simpler and cheaper than methods used previously, e.g. hot pressing. The inorganic ion exchangers, sodium titanate and ZrO2, were turned into final ceramic waste form by mixing them with a Finnish red clay in weight ratio 1:4 at maximum. The tiles moulded frKm the wet, bakeable mixture were ceramized at 1020–1060°C. The leach rates of Sr, Cs and Co from the tiles determind by a 7 dynam c ISO-test were after six months of leaching 10−6−10−7 g/cm2/d, in decreasing order. Mechanically the tiles are very durable: flexural strengths were in the range of 20–45 meganewtons per square meter.

Instrumental neutron activation analysis of lanthanides and coexisting elements in monazite samples and group separation using synthesized inorganic ion exchangers

2020 ◽  
Vol 108 (11) ◽  
pp. 901-912
Author(s):  
Mohamed A. Ghamry ◽  
Fatma H. El-Sweify ◽  
Alaa El-Din A. Abdel-Fattah ◽  
Shorouk M. Aly ◽  
Mohamed F. El-Shahat
Keyword(s):  
Neutron Activation Analysis ◽  
Instrumental Neutron Activation Analysis ◽  
Activation Analysis ◽  
Neutron Activation ◽  
Group Separation ◽  
Ion Exchangers ◽  
Inorganic Ion Exchangers ◽  
Inorganic Ion ◽  
Lanthanide Elements ◽  
Instrumental Neutron Activation

AbstractSamples of Egyptian monazite ore obtained from black sand of Abu-Khashaba, Rashied (Rosetta) area on the Mediterranean Sea coast were analyzed for some lanthanides and coexisting elements using instrumental neutron activation analysis (INAA). The analyses were carried out qualitatively and quantitatively for the elements Ce, Nd, Eu, Gd, Tb, Yb and Sc, La as well as the accompanying elements Co, Cr, Fe, Hf, Nb, Zn, Zr in addition to the actinides Th and U; whereas after relatively longer decay time the following lanthanide elements were analyzed: Ce, Nd, Eu, Gd, Tb, Yb and Sc, beside the accompanying elements Co, Cr, Fe, Hf, Nb, Zn, Zr and Th. Two certified reference materials (CRM) were used in this study. For sorption studies, radioactive isotopes 141Ce, 160Tb, 169Yb, 95Zr, 181Hf, and 95Nb were prepared by neutron irradiation to trace the adsorption behaviors of their corresponding elements under certain conditions. Furthermore, radiochemical separation of the analyzed elements in the irradiated monazite samples in sulfuric acid solutions was carried out. Ion exchange technique was applied under static and dynamic conditions and the employed inorganic ion exchangers were locally synthesized and characterized using FT-IR and scanning electron microscopy (SEM) tools. Good group separation of the analyzed lanthanide elements from the accompanying elements was achieved.

Inorganic ion exchangers—IX

1974 ◽  
Vol 36 (10) ◽  
pp. 2377-2383 ◽  
Author(s):  
Sten Ahrland ◽  
Nils-Olof Björk ◽  
Robert Blessing ◽  
Richard Herman
Keyword(s):  
Ion Exchangers ◽  
Inorganic Ion Exchangers ◽  
Inorganic Ion

Amine cobalt(II) hexacyanoferrate(II) compounds as inorganic ion exchangers

1968 ◽  
Vol 40 (7) ◽  
pp. 1135-1136 ◽  
Author(s):  
Richard B. Hahn ◽  
Henry C. Klein
Keyword(s):  
Ion Exchangers ◽  
Inorganic Ion Exchangers ◽  
Inorganic Ion

Statistical Characteristics and Correlation Analysis for Control Index of Soil-Aggregate Mixture

2013 ◽  
Vol 718-720 ◽  
pp. 1872-1877 ◽  
Author(s):  
Xu Xi Chang ◽  
Xie Jian Ming ◽  
Jiang Ling Fa ◽  
Chen Shan Xiong
Keyword(s):  
Grain Size ◽  
Correlation Analysis ◽  
Normal Distribution ◽  
Large Scale ◽  
Soil Aggregate ◽  
Site Preparation ◽  
Statistical Characteristics ◽  
Coarse Grain ◽  
Systematic Research ◽  
Large Variability

Currently, the soil-aggregate mixture has been widely used in some large-scale site preparation projects, compaction characteristics has been pay more attention by many engineers and researchers. However, systematic research is insufficient on how to choose the filler. Moreover, some industry regulations are different on the requirements about filler. This paper relies on a certain big site preparation projects, discussing statistical characteristics and correlation on the maximal grain size, contents of the coarse grain, gradation and other parameters of soil-aggregate mixture. The results show that the maximal and the median grain size have small discreteness and normal distribution, indicating site filler is easy to reach the requirement; The coefficient of curvature, coefficient of nonuniformity and the coarse grain content have large discreteness, and dont obey normal distribution, indicating the filler has large variability. The median grain size is highly relevant to the coarse grain content; the maximal grain size isnt relevant to the coefficient of nonuniformity, the coefficient of curvature and the coarse grain content. According to the results of correlation analysis, we suggest that the importance order follow by coarse grain content, the maximum grain size and gradation for the control parameters of filler. This research may be significant to other similar projects.

Implementing post-trial access plans for HIV prevention research

2018 ◽  
Vol 44 (5) ◽  
pp. 354-358 ◽  
Author(s):  
Amy Paul ◽  
Maria W Merritt ◽  
Jeremy Sugarman
Keyword(s):  
Hiv Prevention ◽  
Large Scale ◽  
Healthcare Systems ◽  
System Level ◽  
Planning Under Uncertainty ◽  
Work Related ◽  
Prevention Trials ◽  
Practical Experiences ◽  
Post Trial ◽  
Local Healthcare

Ethics guidance increasingly recognises that researchers and sponsors have obligations to consider provisions for post-trial access (PTA) to interventions that are found to be beneficial in research. Yet, there is little information regarding whether and how such plans can actually be implemented. Understanding practical experiences of developing and implementing these plans is critical to both optimising their implementation and informing conceptual work related to PTA. This viewpoint is informed by experiences with developing and implementing PTA plans for six large-scale multicentre HIV prevention trials supported by the HIV Prevention Trials Network. These experiences suggest that planning and implementing PTA often involve challenges of planning under uncertainty and confronting practical barriers to accessing healthcare systems. Even in relatively favourable circumstances where a tested intervention medication is approved and available in the local healthcare system, system-level barriers can threaten the viability of PTA plans. The aggregate experience across these HIV prevention trials suggests that simply referring participants to local healthcare systems for PTA will not necessarily result in continued access to beneficial interventions for trial participants. Serious commitments to PTA will require additional efforts to learn from future approaches, measuring the success of PTA plans with dedicated follow-up and further developing normative guidance to help research stakeholders navigate the complex practical challenges of realising PTA.

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