scholarly journals A Comprehensive Membrane Process for Preparing Lithium Carbonate from High Mg/Li Brine

Membranes ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 371
Author(s):  
Wenhua Xu ◽  
Dongfu Liu ◽  
Lihua He ◽  
Zhongwei Zhao

The preparation of Li2CO3 from brine with a high mass ratio of Mg/Li is a worldwide technology problem. Membrane separation is considered as a green and efficient method. In this paper, a comprehensive Li2CO3 preparation process, which involves electrochemical intercalation-deintercalation, nanofiltration, reverse osmosis, evaporation, and precipitation, was constructed. Concretely, the electrochemical intercalation-deintercalation method shows excellent separation performance of lithium and magnesium, and the mass ratio of Mg/Li decreased from the initial 58.5 in the brine to 0.93 in the obtained lithium-containing anolyte. Subsequently, the purification and concentration are performed based on nanofiltration and reverse osmosis technologies, which remove mass magnesium and enrich lithium, respectively. After further evaporation and purification, industrial-grade Li2CO3 can be prepared directly. The direct recovery of lithium from the high Mg/Li brine to the production of Li2CO3 can reach 68.7%, considering that most of the solutions are cycled in the system, the total recovery of lithium will be greater than 85%. In general, this new integrated lithium extraction system provides a new perspective for preparing lithium carbonate from high Mg/Li brine.

1992 ◽  
Vol 25 (3) ◽  
pp. 117-120 ◽  
Author(s):  
T. Bilstad ◽  
M. V. Madland

Leachates from chemical and domestic landfills are defined as hazardous wastewater. Quantitative and qualitative control of leachate can be performed by membrane separation of the total produced leachate volume. Dissolved and suspended solids in the leachate are removed from the major portion of the water phase and either returned to the landfill or further treated. The particle - free permeate meets the effluent requirements for direct discharge to virtually any watercourse. An untreated leachate flow is concentrated thirteen times by tubular type reverse osmosis. The separation efficiencies are 99% for iron, copper, chromium and zinc. For suspended solids the removal is 100%.


2013 ◽  
Vol 284-287 ◽  
pp. 557-561
Author(s):  
Jie Li Fan ◽  
Wei Ping Huang

The two-degrees-of-freedom VIV of the circular cylinder with high mass-ratio is numerically simulated with the software ANSYS/CFX. The VIV characteristic is analyzed in the different conditions (Ur=3, 5, 6, 8, 10). When Ur is 5, 6, 8 and 10, the conclusion which is different from the cylinder with low mass-ratio can be obtained. When Ur is 3, the frequency of in-line VIV is twice of that of cross-flow VIV which is equal to the frequency ratio between drag force and lift force, and the in-line amplitude is much smaller than the cross-flow amplitude. The motion trace is the crescent. When Ur is 5 and 6, the frequency ratio between the drag force and lift force is still 2, but the main frequency of in-line VIV is mainly the same as that of cross-flow VIV and the secondary frequency of in-line VIV is equal to the frequency of the drag force. The in-line amplitude is still very small compared with the cross-flow amplitude. When Ur is up to 8 and 10, the frequency of in-line VIV is the same as the main frequency of cross-flow VIV which is close to the inherent frequency of the cylinder and is different from the frequency of drag force or lift force. But the secondary frequency of cross-flow VIV is equal to the frequency of the lift force. The amplitude ratio of the VIV between in-line and cross-flow direction is about 0.5. When Ur is 5, 6, 8 and 10, the motion trace is mainly the oval.


2019 ◽  
Vol 19 (12) ◽  
pp. 174 ◽  
Author(s):  
Quan-Wang Han ◽  
Li-Fang Li ◽  
Deng-Kai Jiang

1989 ◽  
Vol 107 ◽  
pp. 348-349
Author(s):  
Bruce J. Hrivnak

Recent theories of the origin and evolution of contact binaries suggest that the two stars evolve into contact through angular momentum loss (AML; Mochnacki 1981, Vilhu 1982). When in contact, the system then evolves toward smaller mass ratio through mass transfer from the secondary to the primary component (Webbink 1976, Rahunen and Vilhu 1982). Most contact binaries have mass ratios of 0.3 to 0.5.


Author(s):  
Xiao-Hui Fang ◽  
Shengbang Qian ◽  
Miloslav Zejda ◽  
Soonthornthum Boonrucksar ◽  
Xiao Zhou ◽  
...  

Abstract 1SWASP J161335.80$-$284722.2 (hereafter J161335) is an eclipsing red-dwarf binary with an orbital period of $0.229778\:$d, which is around the short-period limit for contact binaries. Three sets of multi-color light curves of J161335 were obtained from different telescopes in 2015 and 2016 and are analyzed using the Wilson–Devinney method. We discovered that the system is a W-type contact system with a contact degree of 19% and a high mass ratio of 0.91. By using all available eclipse times, we found that the observed $-$ calculated $(O-C)$ diagram displays a cyclic oscillation with an amplitude of 0.00196($\pm 0.00006)\:$d and a period of 4.79($\pm 0.14)\:$yr while it undergoes a downward parabolic change. This downward variation corresponds to a continuous decrease in the orbital period at a rate of $dP/dt = -4.26(\pm$0.01) $\times$ 10$^{-7}\:$d$\:$yr$^{-1}$. The small-amplitude oscillation is explained as the light travel-time effect from the gravitational influence of a third body with a lowest mass of $M _{3}$ = 0.15($\pm 0.01)M_{\,\odot }$. In solving the light curves, we found that the third light is increasing, with the wavelength suggesting that the third body may be a cool red dwarf. This is in agreement with the results obtained by analyzing the $O-C$ diagram. The tertiary red dwarf is orbiting the central red-dwarf binary at an orbital separation of 2.8($\pm 0.2$) au. These results suggest that the J161335 system may be formed through early dynamical interaction where the original low-mass component was replaced by a higher-mass third body and the lower-mass component was kicked out to a wider orbit. In this way, a hierarchical triple system similar to J161335 with a high-mass-ratio binary and a small close-in third body is formed.


2014 ◽  
Vol 625 ◽  
pp. 680-684 ◽  
Author(s):  
Dzeti Farhah Mohshim ◽  
Hilmi Mukhtar ◽  
Zakaria Man

— Polymeric membranes have been extensively used in membrane gas separation process. Nowadays, peoples are modifying the membrane by many ways like coating with ionic liquids to further enhance the membrane separation performance. In this project, ionic liquid modified polymeric membranes (ILMPM) have been successfully developed by blending the ionic liquids with the polymer via solvent evaporation method. The ionic liquid used was 1-ethyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide, ([emim][Tf2N]) and for comparison purpose, the compositions were varied at 10 and 20 wt/wt%. In general, the blending of [emim][Tf2N] and PES has produced dense membrane with miscible mixture without any phase separation. It was observed that, the CO2permeance of ILMPM has been improved about 271% as compared to the pure PES membrane. However, the CO2permeance decreased with increasing operating pressure, yet the ILMPM CO2permeance still higher than CO2permeance of pure PES membrane. In addition, the CO2/CH4separation performance has greatly increased about 162% as the IL composition is increased. This initial study has proven that IL helps to enhance of CO2permeation and improve selectivity.


2011 ◽  
Vol 63 (9) ◽  
pp. 1795-1800 ◽  
Author(s):  
A. Y. Bagastyo ◽  
J. Keller ◽  
D. J. Batstone

Reverse osmosis membrane separation is the leading method for manufacturing potable purified water. It also produces a concentrate stream, namely reverse osmosis concentrates (ROC), with 10–20% of the water, and almost all other compounds. One method for further treating this stream is by coagulation with ferric chloride. This study evaluates removed organics in ROC treated with ferric chloride. Fractionation with ultrafiltration membranes allows separation of organics based on a nominal molecular weight. A stirred cell system was applied for serial fractionation to classify organic compounds into six groups of <0.5 kDa, 0.5–1 kDa, 1–3 kDa, 3–5 kDa, 5–10 kDa and >10 kDa. The study found that raw ROC is rich in low molecular weight compounds (<1 kDa) with almost 50% of the organics. These compounds include soluble microbial products (SMPs) and smaller humic and fulvic acids as indicated by fluorescence scanning. Conversely, colour was mostly contributed by medium to large molecules of humic and fulvic acids (>0.5 kDa). Organics and colour were reduced in all molecular groups at an optimum treatment dose 1.48 mM FeCl3 and a pH of 5. However, ferric seemed to effectively remove colour in all size ranges while residual nitrogen was found mostly in the <1 kDa sizes. Further, the fluorescence indicated that larger humic and fulvic acids were removed with considerable SMPs remaining in the <0.5 kDa.


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