Pore Solution Chemistry of Simulated Low Level Liquid Waste Incorporated Cement Grouts

1995 ◽  
Vol 412 ◽  
Author(s):  
Sadananda Sahu ◽  
Sidney Diamond
Keyword(s):  
Pore Solution ◽  
Liquid Waste ◽  
Early Period ◽  
Solution Chemistry ◽  
Ion Concentration ◽  
High Concentration ◽  
Chemical Methods ◽  
Low Level ◽  
Gas Condensates ◽  
Cement Grouts

AbstractExpressed pore solutions from simulated low level liquid waste cement grouts cured at room temperature, 50°C and 90°C for various duration were analyzed by standard chemical methods and ion chromatography. The solid portions of the grouts were formulated with portland cement, fly ash, slag, and attapulgite clay in the ratios of 3:3:3:1. Two different solutions simulating off-gas condensates expected from vitrification of Hanford low level tank wastes were made. One is highly alkaline and contains the species Na+, PO43-, NO2-, NO3- and OH-. The other is carbonated and contains the species Na+, PO43-, NO2- NO3- and CO32- In both cases phosphate rapidly disappeared from the pore solution, leaving behind sodium in the form of hydroxide. The carbonates were also removed from the pore solution to form calcium carbonate and possibly calcium monocarboaluminate. These reactions resulted in the increase of hydroxide ion concentration in the early period. Subsequently there was a significant reduction OH- and Na+ ion concentrations. In contrast high concentration of NO2- and NO3- were retained in the pore solution indefinitely.

scholarly journals Pore Solution Chemistry of Calcium Sulfoaluminate Cement and Its Effects on Steel Passivation

2019 ◽  
Vol 9 (6) ◽  
pp. 1092 ◽  
Author(s):  
Lingbo Wang ◽  
Shulin Zhan ◽  
Xudong Tang ◽  
Qiang Xu ◽  
Kuangliang Qian
Keyword(s):  
Pore Solution ◽  
Solution Chemistry ◽  
Ex Situ ◽  
High Concentration ◽  
Calcium Sulfoaluminate Cement ◽  
Calcium Sulfoaluminate ◽  
Low Co2 ◽  
New Type ◽  
The Stability ◽  
Protection Capability

Calcium sulfoaluminate cement (CSA) is a type of low-CO2 binder which has been widely applied in the production of concrete. To investigate the protection capability offered by CSA to keep steel from corrosion, the pore solution chemistry of CSA on steel passivation was investigated in this study. The pore solution of CSA pastes, extracted by an ex situ leaching method, was studied and compared with ordinary Portland cement (OPC). The results show that the alkalinity of the CSA pore solution is not only much lower than that of OPC, but also that a new type of ion, Al(OH)4−, and high concentration of SO42− were detected in the liquid phase of CSA. Based on pore solution chemistry analysis, a simulated pore solution (SPS) system was designed to assess the comprehensive impact of alkalinity and ion composition, featured as properties of CSA, on steel passivation. The results of the corrosion potential evolution highlight the importance of alkalinity in passivation. SO42− can cause depassivation when there is not enough hydroxyl, but Al(OH)4− is able to maintain the alkalinity of the system, enhancing the stability of the passive film.

Low-Level Liquid Waste Treatment System Technical Design in China

2013 ◽  
Author(s):  
Juan Zhao
Keyword(s):  
Ion Exchange ◽  
Radioactive Waste ◽  
Waste Treatment ◽  
Fuel Cycle ◽  
Liquid Radioactive Waste ◽  
Liquid Waste ◽  
Spent Fuel ◽  
Nuclear Facilities ◽  
High Concentration ◽  
Low Level

Radioactive wastes are produced within the nuclear fuel cycle operations (uranium conversion and enrichment, fuel fabrication and spent fuel reprocessing). Evaporation is a proven method for the treatment of liquid radioactive waste providing both good decontamination and high concentration. Two technical designs of nuclear facilities for low-level liquid radioactive waste treatment are presented in the paper and the evaluation of both methods, as well. One method is two-stage evaporation, widely used in the People’s Republic of China’s nuclear facilities; another is two evaporator units and subsequently ion exchange, which is based on the experience gained from TIANWAN nuclear power plant. Primary evaporation and ion exchange ensure the treated waste water discharged to environment by controlling the condensate radioactivity, and secondary evaporation is to control concentrates in a limited salt concentration.

Separation and Recovery of Sodium Nitrate From Low-Level Radioactive Liquid Waste by Electrodialysis

2010 ◽  
Author(s):  
Yoshihiro Meguro ◽  
Atsushi Kato ◽  
Yoko Watanabe ◽  
Kuniaki Takahashi
Keyword(s):  
Sodium Nitrate ◽  
Nitrate Solution ◽  
Liquid Waste ◽  
Sodium Ion ◽  
High Concentration ◽  
Radioactive Liquid Waste ◽  
Nitrate Ion ◽  
Low Level ◽  
Sodium Nitrate Solution ◽  
Exchange Membrane

An advanced method, in which electrodialysis separation of sodium nitrate and decomposition of nitrate ion are combined, has been developed to remove nitrate ion from low-level radioactive liquid wastes including nitrate salts of high concentration. In the electrodialysis separation, the sodium nitrate was recovered as nitric acid and sodium hydroxide. When they are reused, it is necessary to reduce the quantity of impurities getting mixed with them from the waste fluid as much as possible. In this study, therefore, a cation exchange membrane with permselectivity for sodium ion and an anion exchange membrane with permselectivity for monovalent anion were employed. Using these membranes sodium and nitrate ions were effectively removed form a sodium nitrate solution of high concentration. And also it was confirmed that sodium ion was successfully separated from cesium and strontium ions and that nitrate ion was separated from sulfate and phosphate ions.

Development of Separation Technique of Sodium Nitrate From Low-Level Radioactive Liquid Waste Using Electrodialysis With Selective Ion-Exchange Membranes

2013 ◽  
Author(s):  
Keita Irisawa ◽  
Akinori Nakagawa ◽  
Takashi Onizawa ◽  
Takafumi Kogawara ◽  
Keiji Hanada ◽  
...  
Keyword(s):  
Sodium Nitrate ◽  
Liquid Waste ◽  
High Concentration ◽  
Radioactive Liquid Waste ◽  
Nitrate Ion ◽  
Advanced Method ◽  
Low Level ◽  
Fundamental Investigation ◽  
Experimental Parameters ◽  
Liquid Wastes

An advanced method, in which electrodialysis separation of sodium nitrate and decomposition of nitrate ion are combined, has been developed to remove nitrate ion from low-level radioactive liquid wastes including nitrate salts of high concentration. An engineering scale apparatus with two electrodialytic devices, in which the sodium and nitrate ions were separately removed by each device, was produced on the basis of the results of fundamental investigation previously reported, and the performance of the apparatus was tested. Both the ions were successfully removed at the same time, though these ions were separately transferred using two electrodialytic devices. And also effect of several experimental parameters such as current and temperature on current efficiency of both the ions of each device was investigated.

Separation of Heavy Metal Ions from the Solution Obtained by Leaching Low-Grade Pyrolusite with Pyrite and H2SO4

2013 ◽  
Vol 773 ◽  
pp. 283-288
Author(s):  
Xing Zou ◽  
Xiang Quan Chen ◽  
Hai Chao Xie ◽  
Xiao Dan Qiu
Keyword(s):  
Heavy Metal ◽  
Metal Ions ◽  
Heavy Metal Ions ◽  
Separation Efficiency ◽  
Ph Value ◽  
Sulfate Solution ◽  
Ion Concentration ◽  
Manganese Sulfate ◽  
Low Grade ◽  
High Concentration

The manganese sulfate solution leached from low-grade pyrolusite with pyrite and H2SO4 contains heavy metal ions of high concentration, influencing the quality of the final products of manganese compounds and causing manganese ions not to be electrolyzed. The present study was focused on the separation of Co, Ni and Zn ions from the leached solution with BaS. By controlling the pH value at 5.0-6.5, temperature at 50-60°C, reaction time at 15 min and mixing velocity at 78 rpm, the heavy metal ions could be separated effectively. Under the above optimized conditions, the ion concentration of Co, Ni, and Zn in the solution was reduced to 0.06 mg.L-1, 0.27mg.L-1 and 0.01mg.L-1, and the separation efficiency was 99.72%, 99.18% and 99.9% respectively. The obtained pure solution meets the demands of manganese electrowinning.

Phosphate biogeochemical barrier for uranium in situ immobilization in an aquifer nearby sludge repository

2021 ◽  
Author(s):  
Grigory Artemiev ◽  
Alexey Safonov ◽  
Nadezhda Popova
Keyword(s):  
Essential Elements ◽  
Ion Concentration ◽  
Soluble Form ◽  
High Concentration ◽  
Rapid Reduction ◽  
Near Surface ◽  
Nitrate Ions ◽  
Uranium Migration ◽  
Storage Facilities

<p>Uranium migration in the oxidized environment of near-surface groundwater is a typical problem of many radiochemical, ore mining and ore processing enterprises that have sludge storage facilities on their territory. Uranium migration, as a rule, occurs against a high salt background due to the composition of the sludge: primarily, nitrate and sulfate anions and calcium cations. One of the ways to prevent the uranium pollution is geochemical or engineering barriers. For uranium immobilization, it is necessary to create conditions for its reduction to a slightly soluble form of uraninite and further mineralization, for example, in the phosphate form. An important factor contributing to the rapid reduction of uranium is a in the redox potential decreasing and the removal of nitrate ions, which can be achieved through the activation of microflora. It should be added that phosphate itself is one of the essential elements for the development of microflora. This work was carried out in relation to the upper aquifer (7-12 m) near the sludge storage facilities of ChMZ, which is engaged in uranium processing and enrichment. One of the problems of this aquifer, in addition to the high concentration of nitrate ions (up to 15 g / l), is the high velocity of formation waters.<br>In laboratory conditions, the compositions of injection solutions were selected containing sources of organic matter to stimulate the microbiota development and phosphates for uranium mineralization. When developing the injection composition, special attention was paid to assessing the formation of calcite deposits in aquifer conditions to partially reduce the filtration parameters of the horizon and reduce the rate of movement of formation waters. This must be achieved to ensure the possibility of long-term deposition of uranium and removal of nitrate. The composition of the optimal solution was selected and in a series of model experiments the mineral phases containing the lowest hydrated form of the uranium-containing phosphate mineral meta-otenite were obtained.<br>In situ mineral phosphate barrier Formation field tests were carried out in water horizon conditions in a volume of 100m3 by injection of an organic and phosphates mixture. As a result, at the first stage of field work, a significant decreasing nitrate ion concentration, and reducing conditions formation coupled with the dissolved uranium concentration of decreasing were noted.</p>

Bituminization of Low-Level Liquid Waste

1981 ◽  
pp. 219-226
Author(s):  
Teruo Tokubuchi ◽  
Shigeki Kitajima ◽  
Hiroshi Kuribayashi ◽  
Takuro Yagi ◽  
Tomoyoshi Kagawa
Keyword(s):  
Liquid Waste ◽  
Low Level
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