Separation of K2CO3 from Li+ Brine with Aid of CO2 and Trace of Metastable Quaternary System Li+–K+–CO32−–HCO3−–H2O

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Yuli Xue ◽  
Yan Zhang ◽  
Xiaoling Tan ◽  
Wenqing Li ◽  
Zhongshu Li ◽  
...  
Keyword(s):  
Potassium Carbonate ◽  
Alkali Metals ◽  
Quaternary System ◽  
Metastable Phase ◽  
Lithium Carbonate ◽  
West China ◽  
Low Concentration ◽  
Composition Diagram ◽  
High Level ◽  
Natural Brine

AbstractIt is of importance to reclaim single-salt of potash from Li+-type brines of low concentration. In this work the potassium salts KHCO3 was efficiently separated from the lithium carbonate-type brines with the aid of CO2 carbonation. The phase field was provided in which the precipitation of KHCO3 occurs and single-salt of potassium can be obtained. The low concentration of [Li+] was also successfully concentrated to a high level (8.1 g/L), and this concentration can be used as sources for Li+-salts production using pre-developed strategies, which looks forward wider applications of the lithium resources of natural brine. This state-of-art was traced via isotherm evaporation on the quaternary system of Li+–K+–CO32−–H2O at 298.15 K in which the carbonation steps were performed by CO2. Metastable phase diagram was found to consist of three invariant points, seven univariant curves, and four crystallization fields corresponding to Li2CO3, KHCO3, potassium carbonate sesquihydrate (K2CO3 ⋅ 3/2H2O), and a potassium carbonate and potassium bicarbonate double salt (K2CO3 ⋅ 2 KHCO3 ⋅ 1.5H2O). There was no crystallization field corresponding to LiHCO3. The pH-composition diagram and density-composition diagram were also plotted. This work was carried out in aim of extracting/separating single salts of alkali metals from carbonate-type brines of west China.

Extraction of K2CO3 from Low Concentration [K+] Solutions with the Aid of CO2: A Study on the Metastable Phase Equilibrium of K2CO3-Na2CO3-H2O Ternary System

2018 ◽  
Vol 232 (9-11) ◽  
pp. 1741-1753 ◽  
Author(s):  
Shiding Miao ◽  
Shuai He ◽  
Yuli Xue ◽  
Hongen Nian ◽  
Jian Wang ◽  
...  
Keyword(s):  
Ternary System ◽  
Metastable Phase ◽  
Metastable Phase Equilibrium ◽  
West China ◽  
Low Concentration ◽  
Ph Values ◽  
Double Salts ◽  
Phase Study ◽  
Isothermal Evaporation ◽  
Lop Nor

Abstract Food grade (K2CO3 wt.%>99.0%, GB/T 25588-2010) potassium carbonate (K2CO3) has been extracted from low concentration [K+] solutions of K2CO3-Na2CO3-H2O, which refers to a subsystem of brine water in the Lop Nor Lake in West China. Procedures of the isothermal evaporation, crystallization, CO2 acidification, filtration, and calcination were employed to prepare the K2CO3. This research focuses on the phase study of metastable equilibria between K2CO3-Na2CO3-H2O and KHCO3-NaHCO3-H2O. The solubility, density, conductivity, and pH values were determined. Phase diagrams were plotted at temperatures of 298.2 and 313.2 K. At 298.2 K the ternary system of K2CO3-Na2CO3-H2O was found to have double salts in form of solid solutions Na2CO3·K2CO3·(6–12)H2O, which would hinder the process of getting pure K2CO3 by the means of isothermal evaporation. In this protocol the high-pressure CO2 was charged to the ternary carbonate solution, and the K2CO3-Na2CO3-H2O was moved to bicarbonate system KHCO3-NaHCO3-H2O. This quaternary system is of a simple co-saturation type of diagram, in which a solid solution (KHCO3·NaHCO3) was found to be greatly affected by temperatures. This finding affords efficient separation of KHCO3 from the KHCO3-NaHCO3-H2O solutions.

The reactions of some compounds of manganese with molten lithium carbonate-sodium carbonate-potassium carbonate eutectic

1983 ◽  
Vol 36 (1) ◽  
pp. 25 ◽  
Author(s):  
I Salarzadeh ◽  
SA Tariq
Keyword(s):  
Carbon Dioxide ◽  
Carbon Monoxide ◽  
Sodium Carbonate ◽  
Potassium Carbonate ◽  
Alkali Metals ◽  
Reaction Medium ◽  
Lithium Carbonate ◽  
Molten Lithium ◽  
Oxide Ions ◽  
Carbonate Melt

The reactions of MnO, MnCl2, MnCO3, MnSO4, Mn2O3, Mn3O4, MnO2 and KMnO4 with molten lithium carbonate-sodium carbonate-potassium carbonate eutectic were studied under argon as well as carbon dioxide atmospheres. Final products for MnCl2 reaction consisted of a mixture of oxy anions, MnO2- and MnO32-, and those for MnCO3 were MnO32- and Mn2O52- as were for the reactions of MnSO4 and MnO2. Mn2O3 and Mn3O4 reacted to form the oxy anion, MnO2-. KMnO4 decomposed to form initially a mixture of Mn7O164- and MnO42-. These oxy anions reacted further with the eutectic to produce the oxy anion, MnOS32-. Three alkali metals were present as cationic species with the above manganese oxy anions in different ratios. The carbonate melt acted both as a reaction medium and as a Lux-Flood base, that is a donor of oxide ions evolving carbon dioxide which was partly reduced to carbon monoxide in the reactions involving manganese(II) compounds. The stoichiometries of these reactions have been suggested. Manganese(II) oxide was found to be unreactive with the carbonate eutectic.

Removal of Fission Products in the Spent Electrolyte Using Iron Phosphate Glass as a Sorbent

2010 ◽  
Author(s):  
Ippei Amamoto ◽  
Naoki Mitamura ◽  
Tatsuya Tsuzuki ◽  
Yasushi Takasaki ◽  
Atsushi Shibayama ◽  
...  
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Phosphate Glass ◽  
Alkali Metals ◽  
Fission Products ◽  
Iron Phosphate ◽  
Experimental Result ◽  
Filtration Method ◽  
High Level ◽  
Filtration Experiment

This study is carried out to make the pyroprocessing hold a competitive advantage from the viewpoint of environmental load reduction and economical improvement. As one of the measures to reduce the volume of the high-level radioactive waste (HLW), the phosphate conversion method is applied for removal of fission products (FP) from the melt, referring to the spent electrolyte in this paper. Among the removing target chlorides in the spent electrolyte i.e., alkali metals, alkaline earth metals and rare earth elements, only the rare earth elements and lithium form the precipitates as insoluble phosphates by reaction with Li3PO4. The sand filtration method was applied to separate FP precipitates from the spent electrolyte. The iron phosphate glass (IPG) powder, which is a compatible material for the immobilization of FP, was used as a filter medium. After filtration experiment, it was proven that insoluble FP could almost be completely removed from the spent electrolyte. Subsequently, we attempted to separate the dissolved FP from the spent electrolyte. The IPG was being used once again but this time as a sorbent instead. This is possible because the IPG has some unique characteristics, e.g., changing the valence of iron, which is one of its network modifiers due to its manufacturing temperature. Therefore, it would be likely to sorb some FP when the chemical condition of IPG is unstable. We produced three kinds of IPG under different manufacturing temperature and confirmed that those glasses could sorb FP as anticipated. According to the experimental result, its sorption efficiency of metal cations was attained at around 20–40%.

scholarly journals Radiocarbon Dating Problems Using Acetylene as Counting Gas

Radiocarbon ◽  
1990 ◽  
Vol 32 (3) ◽  
pp. 321-324 ◽  
Author(s):  
Mebus A Geyh
Keyword(s):  
Carbon Dioxide ◽  
High Risk ◽  
Radiocarbon Dating ◽  
Collaborative Study ◽  
Lithium Carbonate ◽  
High Price ◽  
Fossil Carbon ◽  
High Level ◽  
And Storage ◽  
International Collaborative Study

An investigation of inconsistent Hannover results in the International Collaborative Study (ICS) led to the conclusion that the main reason was contamination of the acetylene used as counting gas with recent and/or fossil carbon by the lithium used for its preparation. Despite the high level of purity of the lithium guaranteed by the producer and storage under argon in cans, different charges were partly covered with contemporary lithium carbonate and fossil oil sometimes was used to preserve the metal. Thorough cleaning of the surface of the lithium rods decreased the contamination but did not remove it entirely, which is evidenced in the wider scatter of the counting rates of various background gases than that of radiocarbon-free tank acetylene. As a result of the high risk of contamination with fossil and/or recent carbon from the acetylene counting gas, the high price of lithium, and the time-consuming preparation, the Hannover 14C Laboratory will use carbon dioxide instead of acetylene as counting gas in the future.

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