• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.18 no.3
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• pp.373-382
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• 2020

This study proposes a method of separating uranium (U) and minor actinides from rare earth (RE) elements in the LiCl-KCl salt system. Several RE metals were used to reduce UCl₃ and MgCl₂ from the eutectic LiCl-KCl salt systems. Five experiments were performed on drawdown U and plutonium (Pu) surrogate elements from RECl₃-enriched LiCl-KCl salt systems at 773 K. Via the introduction of RE metals into the salt system, it was observed that the UCl₃ concentration can be lowered below 100 ppm. In addition, UCl₃ was reduced into a powdery form that easily settled at the bottom and was successfully collected by a salt distillation operation. When the RE metals come into contact with a metallic structure, a galvanic interaction occurs dominantly, seemingly accelerating the U recovery reaction. These results elucidate the development of an effective and simple process that selectively removes actinides from electrorefining salt, thus contributing to the minimization of the influx of actinides into the nuclear fuel waste stream.

• Journal of the Korea Organic Resources Recycling Association
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• v.12 no.3
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• pp.86-94
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• 2004

The characteristics of food waste in our country is high contents of water and sodium chloride(NaCl). Average water contents of household garbage was 80.0%, and those of wastes of restaurants and of wholesale market of agricultural products was 76.9% and 90.0%, respectively. The NaCl contents were high in household garbage and restaurant's waste as 3.36% and 4.84%, respectively. The NaCl contents of food waste composts made by various techniques known upto now were under the level of 1% by fresh weight basis. But these techniques has some problem that is environment pollution from treated water and high equipment cost. The application to agricultural land of food waste compost that is not sufficiently removed NaCl was considered to be improper due to salt accumulation in soils and plant growth inhibition by salt stress. The purpose of this study is to decompose NaCl in food waste compost using triple salt and this method is differ from existing chemical method. Also, reaction of NaCl with triple salt produced KCl that is basic material of potassium fertilizer. The experiment results of growing lettuce produced difference between food waste compost and treated food waste compost with triple salt. The latter got more high sprouting ratio and a growth rate.

• Korean Journal of Environmental Agriculture
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• v.42 no.2
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• pp.159-167
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• 2023

Food waste (FW) emissions in South Korea amounted to 4.77 million tons in 2021, and continue to increase. Various technologies have been developed to treat FW, with recent research focusing on biochar production through pyrolysis to reduce FW. However, the agricultural application of food waste-biochar (FWBC) is limited by the salt accumulated during pyrolysis. This study investigated salt removal from and the kinetic characteristics of FWBC, and subsequently evaluated its agricultural applications. FW was pyrolyzed at 350℃ for 4 h, and subsequently washed for 0.1, 0.25, 0.5, 0.75, 1, 5, 15, and 30 min to remove salt. FWBC had a salt concentration of 5.75%, which was effectively removed through washing. The salt concentration decreased rapidly at the beginning (1 min) and then slowly decreased, unlike in FW, in which the salt decreased continuously and slowly. The salt removal speed constant (K) was 1.5586 (Stage 1, FWBC) > 0.0445 (Stage 2, FWBC) > 0.0026 (FW). In a lettuce cultivation experiment, higher biomass was achieved using washed FWBC than when using unwashed FWBC and FW, and soil properties were improved. Overall, these findings suggest that although FW reduction using pyrolysis causes a salt accumulation problem, the salt can be effectively removed through washing. The use of washed FWBC can enhance plant growth and soil properties.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.7 no.2
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• pp.73-78
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• 2009

The decay heat of Cs and Sr contained in a LiCl waste salt, generated from an electrolytic reduction process in pyroprocessing of spent nuclear fuel, has been calculated. The calculation has been carried out under some assumptions that most of the LiCl waste is purified and recycled to main process, and the residual is fabricated to make a waste form. As a result, the decay heat from daughter nuclides such as Ba and Y seems to be maximum 4.6 times higher than that from their parent nuclides such as Cs and Sr. The thermal release from Cs and Sr in the LiCl waste is the maximum around the first one month, so an cooling system operation for some time at the beginning would be suggested to control a rapid increase in the temperature of the LiCl waste salt.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.16 no.1
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• pp.1-10
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• 2018

A simplified flowsheet for pyroprocessing commercial spent fuel is proposed in which the only salt treatment step is actinide drawdown from electrorefiner salt. Actinide drawdown can be performed using a simple galvanic reduction process utilizing the reducing potential of gadolinium metal. Recent results of equilibrium reduction potentials for Gd, Ce, Nd, and La are summarized. A description of a recent experiment to demonstrate galvanic reduction with gadolinium is reviewed. Based on these experimental results and material balances of the flowsheet, this new variant of the pyroprocessing scheme is expected to meet the objectives of minimizing cost, maximizing processing rate, minimizing proliferation risk, and optimizing the utilization of geologic repository space.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.20 no.3
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• pp.259-268
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• 2022

Molten salt consisting primarily of eutectic LiCl-KCl is currently being used in electrorefiners in the Fuel Conditioning Facility at Idaho National Laboratory. Options are currently being evaluated for storing this salt outside of the argon atmosphere hot cell. The hygroscopic nature of eutectic LiCl-KCl makes is susceptible to deliquescence in air followed by extreme corrosion of metallic cannisters. In this study, the effect of occluding the salt into a zeolite on water sorption/desorption was tested. Two zeolites were investigated: Na-Y and zeolite 4A. Na-Y was ineffective at occluding a high percentage of the salt at either 10 or 20wt% loading. Zeolite-4A was effective at occluding the salt with high efficiency at both loading levels. Weight gain in salt occluded zeolite-4A (SOZ) from water sorption at 20% relative humidity and 40℃ was 17wt% for 10% SOZ and 10wt% for 20% SOZ. In both cases, neither deliquescence nor corrosion occurred over a period of 31 days. After hydration, most of the water could be driven off by heating the hydrated salt occluded zeolite to 530℃. However, some HCl forms during dehydration due to salt hydrolysis. Over a wide range of temperatures (320-700℃) and ramp rates (5, 10, and 20℃ min^-1), HCl formation was no more than 0.6% of the Cl^- in the original salt.

• The International Journal of Costume Culture
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• v.4 no.1
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• pp.18-24
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• 2001

Agricultural drainage salt generated during irrigation of crops in San Joaquin Valley, California, exceeds 600,000 tons annually and cumulates in the field in a rapid rate. As a result, the waste is taking out more farmlands for salt storage and disposal, imposing serious concerns to environment and local agricultural industry. In searching for a potential solution to reduce or eliminate the waste, this research explored feasibility of producing a value -added product, sodium sulfate, from the waste and utilizing the product in textile dyeing. The results indicated that sodium sulfate could be produced from the salt and could be purified by a recrystalization method in a temperature range within the highest and lowest daily temperatures in summer in the alley. The recovered sodium sulfate samples, with purities ranging from 67% to 99.91, were compared with commercially available sodium sulfate in direct dyeing of cotton fabrics. The salt samples recovered from Mendata, California (〉98.8% sodium sulfate) cause little color difference in the dyeing with selected direct dyes, and the purified salt (Ⅲ) (99.91% sodium sulfate) is more applicable for direct dyeing of cotton fabrics if it has no other toxic effects. The recovered sodium sulfate from certain areas in the valley could not be employed in direct dyeing due to the high level of impurities in it.

• Nuclear Engineering and Technology
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• v.53 no.12
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• pp.3952-3965
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• 2021

In this study, volcanic ash was used as raw material to prepare waste forms with different silicon/aluminum (Si/Al) molar ratios to immobilize sodium-salt waste (SSW) containing simulated ¹³⁷Cs. Effects of Si/Al molar ratios (3:1 and 2:1) and sodium salts on sintering behavior of waste forms and immobilization mechanism of Cs⁺ were investigated. Results indicated that the main mineral phase of sintered waste-form matrixes was albite, and the formation of major phases was found to depend on Si/Al molar ratios. Si/Al molar ratio of 2 was favorable for the formation of pollucite, and the formation and crystallization of mineral phases were also decided based on physicochemical characteristics of sodium salts. Furthermore, product consistency test results indicated that the immobilization of Cs⁺ was related to Si/Al molar ratio, types of sodium salts, and glassy phase. Waste forms with Si/Al molar ratio of 2 exhibited better ability to immobilize Cs⁺, whereas the influence of sodium salts and glassy phases on the immobilization of SSW showed more complicated relationship. In waste forms with Si/Al molar ratio of 2, Cs⁺ leaching concentrations of samples containing Na₂B₄O₇·10H₂O and NaOH were low. Na₂B₄O₇·10H₂O easily transformed into liquid phase during sintering to consequently achieve low temperature liquid-phase sintering, which is beneficial to avoid the volatilization of Cs⁺ at high temperature. Results clearly reveal that waste forms with Si/Al molar ratio of 2 and containing Na₂B₄O₇·10H₂O show excellent immobilization of Cs⁺.

• Korean Journal of Agricultural Science
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• v.42 no.3
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• pp.177-181
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• 2015

Food waste has been widely considered as a recycling resource to be applied to agricultural lands due to the effects of organic matter and nutrient for plant productivity. but the maturity and salt concentration in the compost produced from food waste processing facilities should be considered firstly, which was little information on compost quality produced from food waste treatment facility. In this study, we examined actual situation of food waste processing facility on the composting of food waste and evaluated the characteristics of composts produced from food waste processing facilities. The quality of composts was analyzed on the basis of the criteria of fertilizer processing manual. The 46% of food waste treatment facility registered composting produced actually the compost mixed with food waste or animal waste. The compost maturity and salt concentration as indicators of the quality of compost were not met 46.8% of composts collected from food waste processing facilities to the criteria of fertilizer processing manual. Also, 15.6%(moisture) were not satisfied with the criteria. In conclusion, the compost produced from food waste processing facilities is firstly required with better compost maturity and reduced salt concentration in order to use to agricultural lands as an amendment.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.15 no.1
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• pp.83-90
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• 2017

The pyroprocessing of spent nuclear fuel generates LiCl-KCl eutectic waste salt containing radioactive rare earth nuclides. It is necessary to develop a simple process for the treatment of LiCl-KCl eutectic waste in a hot-cell facility. In this study, capture and solidification of a rare earth nuclide (Nd) in LiCl-KCl eutectic salt using an inorganic composite with a $Li_2O-Al_2O_3-SiO_2-B_2O_3$ system was conducted to simplify the existing separation and solidification process of rare earth nuclides in LiCl-KCl eutectic waste salt from the pyroprocessing of spent nuclear fuel. More than 98wt% of Nd in LiCl-KCl eutectic salt was captured when the mass ratio of the composite was 0.67 over $NdCl_3$ in the eutectic salt. The content of $Nd_2O_3$ in the Nd captured-composite reached about 50wt%, and this composite was directly fabricated into a homogeneous and chemical resistant glass waste in a monolithic form. These results will be utilized in designing a process to simplify the existing separation and solidification process.