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-hexaoctyl nitrilotriacetamide (HONTA) using mixer-settler extractors in a hot cellBan, Yasutoshi; Suzuki, Hideya*; Hotoku, Shinobu; Tsubata, Yasuhiro
Solvent Extraction Research and Development, Japan, 31(1), p.1 - 11, 2024/00
A demonstration test was performed to separate minor actinides (MA; Am and Cm) by -hexaoctyl nitrilotriacetamide (HONTA) as an extractant using mixer-settler extractors installed in a hot cell. A high-level liquid waste containing MA, and rare earths (RE; Y, La, Nd, and Eu) was used as the feed. HONTA diluted to 0.05 mol/dm
in 
-dodecane was fed as the organic phase, and a part of the organic phase was reused without solvent regeneration. HONTA effectively extracted MA, whereas RE were less extractable. Consequently, the Y, La, Nd, and Eu ratios distributed to a RE fraction were 
99.9%, 99.2%, 61.8%, and 81.4%, respectively. The Am and Cm ratios distributed to an MA fraction were 86.8% and 74.7%, respectively, and a substantial amount of MA (0.12 g) was recovered in the MA fraction by the end of the cumulative duration of 40 h.
Suzuki, Hideya*; Ban, Yasutoshi
Analytical Sciences, 39(8), p.1341 - 1348, 2023/08
Times Cited Count：2 Percentile：71.78(Chemistry, Analytical)The Japan Atomic Energy Agency (JAEA) has proposed the Solvent Extraction from Liquid waste using Extractants of CHON-type for Transmutation (SELECT) process by solvent extraction as a new separation technology to recover minor actinides (MA) from high-level liquid waste (HLLW) produced by spent fuel reprocessing. The MA separation in the SELECT process comprises the batch recovery of MA and rare earths (RE) from HLLW, MA/RE separation, and Am/Cm separation. Three highly practical extractants are used in the MA separation. Furthermore, this flow configuration facilitates the preparation of nitric acid concentrations in the aqueous phase. However, the separation factor between Cm and Nd in the MA/RE separation is small (
= 2.5), requiring many extraction stages for continuous extraction in a mixer-settler. Therefore, this study investigated the separation of only Am from an aqueous nitric acid solution containing MA (Am and Cm) and RE using an organic phase mixed with two extractants alkyl diamideamine with 2-ethylhexyl alkyl chains (ADAAM(EH)) and hexa-n-octylnitrilotriacetamide (HONTA) used in the SELECT process. Under high-concentration nitric acid conditions, Am and La, Ce, Pr, Nd (light lanthanides) were extracted in the ADAAM(EH) + HONTA mixed solvent, whereas Cm, medium, and heavy lanthanides, and Y were partitioned in the aqueous phase. Subsequently, only light lanthanides could be back extracted from the ADAAM(EH) + HONTA mixture solvent containing Am and light lanthanides in low nitric acid concentrations. Furthermore, Am could be easily stripped with 0.2 M or 5 M nitric acid. This method does not require the mutual separation of Cm and Nd, which have low separation factors. Am can be efficiently separated by one extraction and two back-extractions, reducing the number of steps in the SELECT process.
Suzuki, Hideya; Tsubata, Yasuhiro; Kurosawa, Tatsuya*; Kawasaki, Tomohiro*; Shibata, Mitsunobu*; Matsumura, Tatsuro
no journal, ,
The Japan Atomic Energy Agency is engaged in research and development of the "SELECT process" which is a separation technology for recovering actinides from spent fuel. A highly practical reagent, called HONTA, was developed. In the present study, HONTA was tested for the mutual separation of MA and RE.
Suzuki, Hideya*; Ban, Yasutoshi; Tsubata, Yasuhiro; Tsutsui, Nao; Toigawa, Tomohiro; Kurosawa, Tatsuya*; Shibata, Mitsunobu*; Kawasaki, Tomohiro*; Matsumura, Tatsuro
no journal, ,
The Japan Atomic Energy Agency (JAEA) has been studying partitioning technology. Recently, JAEA proposed a new liquid-liquid extraction technology called SELECT process to separate minor actinide (MA) from high-level liquid waste for transmutation. In this process, new extractants (HONTA, ADAAM) with highly practical and high extraction ability for MA was developed. A mixed solvent of HONTA and ADAAM was tested for mutual separation of MA and rare earth elements (RE). In this test, separation of MA and RE was achieved with very high yield. Furthermore, Americium (Am) and Curium (Cm) were separated efficiently with high separation factor values.
Suzuki, Hideya*; Ban, Yasutoshi; Hotoku, Shinobu; Morita, Keisuke; Tsutsui, Nao; Kurosawa, Tatsuya*; Shibata, Mitsunobu*; Kawasaki, Tomohiro*; Matsumura, Tatsuro
no journal, ,
The Japan Atomic Energy Agency (JAEA) has been studying partitioning technology. Recently, JAEA proposed a new liquid-liquid extraction technology called SELECT (Solvent Extraction from Liquid-waste using Extractants of CHON-type for Transmutation) process to separate minor actinide (MA) from high-level liquid waste (HLLW) for transmutation. In this process, new extractants (HONTA, ADAAM) with highly practical and high extraction ability for MA was developed. In the present study, a new solvent extraction method using a mixture of HONTA and ADAAM was investigated. In the tests, it was found that the separation of Am from the simulated HLLW was achieved with very high yield.
Suzuki, Hideya*; Shimojo, Kojiro; Emori, Tatsuya; Tsutsui, Nao; Kurosawa, Tatsuya*; Shibata, Mitsunobu*; Kawasaki, Tomohiro*; Ban, Yasutoshi
no journal, ,
The Japan Atomic Energy Agency (JAEA) has been studying partitioning and transmutation (P&T) systems. In P&T, JAEA proposed a novel hydrometallurgical process called "SELECT (Solvent Extraction from Liquid waste using Extractants of CHON-type for Transmutation) process". In the process, the separation of minor actinide (MA) from the chemically similar Rare earth elements (RE) is the key step. New acidic amide-type extractants, called TONAADA (Tetraoctyl nitriloacetic acid diacetamide) have been developed by JAEA. In this study, solvent extraction tests were performed using TONAADA, THNAADA (hexyl-type), and B-TONAADA (branched side chain type). As a result, the separation of MA from the nitric acid solution was achieved with high separation factor.
Suzuki, Hideya*; Shimojo, Kojiro; Nakamura, Satoshi; Emori, Tatsuya; Kurosawa, Tatsuya*; Shibata, Mitsunobu*; Kawasaki, Tomohiro*; Ban, Yasutoshi
no journal, ,
The Japan Atomic Energy Agency (JAEA) has been studying partitioning and transmutation (P&T) systems. In P&T, JAEA proposed a novel hydrometallurgical process called "SELECT (Solvent Extraction from Liquid waste using Extractants of CHON-type for Transmutation) process" for nuclear fuel reprocessing and minor actinides (MA) separation. In this study, a new MA separation method was investigated to further improve the efficiency of the SELECT process. Batch tests were conducted in a mixed solvent system using the acidic amide-type extractants nitrilotriacetic acid diacetamide with branched side chains (B-TONAADA) and alkyl diamidoamine (ADAAM). As a result, we found an efficient method for separating only americium (Am) from an aqueous nitric acid solution containing MA and rare earth elements by adjusting nitric acid concentration.
Nakamura, Satoshi; Suzuki, Hideya*; Ishii, Sho*; Emori, Tatsuya; Kurosawa, Tatsuya*; Shibata, Mitsunobu*; Shimojo, Kojiro; Ban, Yasutoshi
no journal, ,
To reduce volume and radiotoxicity of high-level radioactive waste, JAEA has been developing a separation process called "SELECT" (Solvent Extraction from Liquid-waste using Extractants of CHON-type for Transmutation) for recovering minor actinides (MA) from high-level radioactive liquid-waste. In this study, the applicability of an acidic diamide-type extractant Branched-TetraOctylNitriloAceticAcidDiAmide (B-TONAADA) was investigated with a view to improving the efficiency of MA/Rare Earth Elements (RE) separation in SELECT process. As a results of extraction tests performed with different nitric acid concentrations, specific changes were observed in the lanthanide patterns of distribution ratios, and the distribution ratios of MA were higher than those of RE over a wide range of nitric acid concentrations.
Suzuki, Hideya*; Nakamura, Satoshi; Emori, Tatsuya; Kurosawa, Tatsuya*; Shibata, Mitsunobu*; Kawasaki, Tomohiro*; Ban, Yasutoshi
no journal, ,
The Japan Atomic Energy Agency (JAEA) has been studying partitioning and transmutation systems (P&T). In P&T, JAEA proposed a novel hydrometallurgical process called "SELECT (Solvent Extraction from Liquid waste using Extractants of CHON-type for Transmutation) process". In the SELECT process, HexaOctyl NitriloTriacetAmide (HONTA) with six -octyl side chains is used for the mutual separation of minor actinides (MA) and rare earth elements (RE). In the present study, extraction tests were carried out with HONTA and three nitrilotriacetamides (NTA amides) with different side chains. The results show that the different side chains of NTA amides affect the extraction behaviors of MA and RE.
