Effects of conductive agent type on lithium extraction from salt lake brine with LiFePO_(4) electrodes

Electrochemical lithium extraction from salt lakes is an effective strategy for obtaining lithium at a low cost.Nevertheless,the elevated Mg:Li ratio and the presence of numerous coexisting ions in salt lake brines give rise to challenges,such as prolonged lithium extraction periods,diminished lithium extraction efficiency,and considerable environmental pollution.In this work,Li FePO4(LFP)served as the electrode material for electrochemical lithium extraction.The conductive network in the LFP electrode was optimized by adjusting the type of conductive agent.This approach resulted in high lithium extraction efficiency and extended cycle life.When the single conductive agent of acetylene black(AB)or multiwalled carbon nanotubes(MWCNTs)was replaced with the mixed conductive agent of AB/MWCNTs,the average diffusion coefficient of Li+in the electrode increased from 2.35×10^(-9)or 1.77×10^(-9)to 4.21×10^(-9)cm^(2)·s^(-1).At the current density of 20 mA·g^(-1),the average lithium extraction capacity per gram of LFP electrode increased from 30.36 mg with the single conductive agent(AB)to 35.62 mg with the mixed conductive agent(AB/MWCNTs).When the mixed conductive agent was used,the capacity retention of the electrode after 30 cycles reached 82.9%,which was considerably higher than the capacity retention of 65.8%obtained when the single AB was utilized.Meanwhile,the electrode with mixed conductive agent of AB/MWCNTs provided good cycling performance.When the conductive agent content decreased or the loading capacity increased,the electrode containing the mixed conductive agent continued to show excellent electrochemical performance.Furthermore,a self-designed,highly efficient,continuous lithium extraction device was constructed.The electrode utilizing the AB/MWCNT mixed conductive agent maintained excellent adsorption capacity and cycling performance in this device.This work provides a new perspective for the electrochemical extraction of lithium using LFP electrodes.

Solvent extraction of rubidium and cesium from salt lake brine with t-BAMBP-kerosene solution

The residues of salt lake brine from which potassium had been removed were used to extract Rb＋ and Cs＋ together with a sulphonated kerosene（SK） solution of 1.0 mol/L 4-tert-butyl-2-（α-methylbenzyl） phenol（t-BAMBP）. Rb＋ and Cs＋ were enriched and separated effectively by precipitating Mg2＋ before extraction and by scrubbing out K＋ and Na＋ repeatedly before stripping. The effects of the volume ratio of organic phase to aqueous extraction phase（O/A）, alkalinity of aqueous phase（c（OH）-）, interference from K＋ and Mg2＋, and ratio the volume of organic phase to aqueous scrubbing phase（O/A′） were investigated. The experimental brine was extracted optimally by 5-stage extraction with 1.0 mol/L t-BAMBP in SK, c（OH-）=1 mol/L, and O/A=1：1. The scrubbing yield of rubidium was only about 10.5% when the extraction solvent was washed 3 times with 1×10-4 mol/L Na OH at O/A′=1：0.5. After 5-stage countercurrent extraction, the final extraction yields of Rb＋ and Cs＋ reached 95.04% and 99.80%, respectively.

Extraction of lithium from salt lake brine by aluminum-based alloys

Salt lake brine was reacted with activated aluminum-based alloys and lithium was precipitated.The effects of aluminum-based alloys on precipitating lithium were investigated and the reasonable alloy used to extract lithium from brine was obtained.The effects of the mole ratio of Al to Li and Ca content of Al-Ca alloy,the initial concentration of lithiumion ion in solution,reaction temperature and reaction time on the adsorption rate of lithium were studied,and the optimized process parameters were determined.The results show that the mole ratio of Al to Li and Ca content of Al-Ca alloy and reaction temperature have great influences on the precipitation rate of lithium.The precipitation rate of lithium reaches 94.6% under the optimal condition,indicating that Al-Ca alloy is suitable for the extraction of lithium from salt lake brine.

Lithium Ion Extraction from the High Ration Mg/Li Salt Lake Brine with Ionic Liquid in Triisobutyl Phosphate and Kerosene

1 Introduction As the lightest metal with the unique properties of energy production and storage,lithium is regarded as the new century energy metal.Lithium and its compounds were widely used in various industrial fields,especially in

Compare on characteristic of different chemical type salt lake brines from Tibet during evaporating

1 Introduction China is a country which has many salt lakes.Tibet is the area where have numerous salt lake,because the sources of water have multiple chemical type,resulting in Tibet salt

The Research Advance and Trend Analysis of the Crystallization Cleaning Technology of Salt Lake Brine Pump in China

Salt Lake brine pump is one of the key equipment in salt lake brine extraction device.As the salt lake brine is a kind of high concentration solution with a variety of chemical constituents,the flow and agitation of saturated

The Phase Diagram of Lithium Salt Systems and Its Application in Extraction of Lithium from Salt Lake Brine

At present,the extraction of lithium from salt lake brine is the new trend of the salt lake industrialization.The saltine lake lithium resources are extremely rich in western china,especially in Qinghai-Tibetan plateau.Brine of salt

Highly efficient extraction of lithium from salt lake brine by LiAl-layered double hydroxides as lithium-ion-selective capturing material

The extraction of lithium from salt lake brine in the Chinese Qaidam Basin is challenging due to its high Mg/Li and Na/Li ratios. Herein, we utilized a reaction-coupled separation technology to separate sodium and lithium ions from a high Na/Li ratio brine(Na/Li = 48.7, w/w) and extracted lithium with Li Al-layered double hydroxides(Li Al-LDHs). The Li Al-LDHs act as lithium-ion-selective capturing materials from multication brines. That is, the lithium ions selectively enter the solid phase to form Li Al-LDHs, and the sodium ions are still retained in the liquid phase. This is because the lithium ions can be incorporated into the structural vacancies of LiAl-LDHs, whereas the sodium ions cannot. The effects of reaction conditions on lithium loss and separation efficiency were investigated at both the nucleation and the crystallization stage, e.g., the nucleation rotating speed, the Li/Al molar ratio, the crystallization temperature and time, and co-existing cations. The lithium loss is as low as 3.93% under optimal separation conditions.The sodium ions remained in the solution. Consequently, an excellent Na/Li separation efficiency was achieved by this reaction-coupled separation technology. These findings confirm that LiAl-LDHs play a critical function in selectively capturing lithium ions from brines with a high Na/Li ratio, which is useful for the extraction of lithium ions from the abundant salt lake brine resources in China.

Doping engineering of lithium-aluminum layered double hydroxides for high-efficiency lithium extraction from salt lake brines

Lithium-aluminum layered double hydroxides(LiAl-LDH)have been be successfully applied in commercial-scale for lithium extraction from salt lake brine,however,further advancement of their applications is hampered by suboptimal Li^(+)adsorption performance and ambiguous extraction process.Herein,a doping engineering strategy was developed to fabricate novel Zn^(2+)-doped LiAl-LDH(LiZnAl-LDH)with remarkable higher Li^(+)adsorption capacity(13.4 mg/g)and selectivity(separation factors of 213,834,171 for Li^(+)/K^(+),Li^(+)/Na^(+),Li^(+)/Mg^(2+),respectively),as well as lossless reusability in Luobupo brine compared to the pristine LiAl-LDH.Further,combining experiments and simulation calculations,it was revealed that the specific surface area,hydrophilic,and surface attraction for Li^(+)of LiZnAl-LDH were significantly improved,reducing the adsorption energy(Ead)and Gibbs free energy(ΔG),thus facilitating the transfer of Li^(+)from brine into interface followed by insertion into voids.Importantly,the intrinsic oxygen vacancies derived from Zn-doping depressed the diffusion energy barrier of Li^(+),which accelerated the diffusion process of Li^(+)in the internal bulk of LiZnAl-LDH.This work provides a general strategy to overcome the existing limitations of Li^(+)recovery and deepens the understanding of Li^(+)extraction on LiAl-LDH.

Extraction of Lithium from Salt Lake Brine with Triisobutyl Phosphate in Ionic Liquid and Kerosene

Three ionic liquids（ILs）, namely, 1-butyl-3-methylimidazolium hexafluorophosphate, 1-butyl-3-me- thylimidazolium bis[（trifluoromethyl）sulfonyl]imide and 1-ethyl-3-methylimidazolium bis[（trifluoromethyl）sul- fonyl]imide with the triisobutyl phosphate（TIBP） and kerosene system were respectively used to extract lithium ion from salt lake brine with a high concentration ratio of magnesium and lithium experimentally. Results indicate that the highest extraction selectivity for lithium was obtained with IL 1-ethyl-3-methylimidazolium bis[（trifluoromethyl）- sulfonyl]imide. The effects of solution pH and phase ratio R（O/A） on the extractive step and the influence of acid concentration of the stripping solution and R（O/A） on the back extraction step were also investigated systematically. The single-step extraction efficiency of lithium ion was 83.71% under the optimal extraction conditions, and the single-step back extraction efficiency was 85.61% with a 1.0 mol/L HCI in 1.0 mol/L NaCI medium as stripping agent at R（O/A）=2. The liquid-liquid extraction mechanism and the complex of the ligand with lithium were proposed.

Hydrochemical Dynamic Characteristics and Evolution of Underground Brine in the Mahai Salt Lake of the Qaidam Basin Qinghai-Tibet Plateau

The mineral rock salts present in the Mahai Salt Lake of the Qaidam basin exhibit high solubilities in water. In addition, the multicomponent underground brine exhibits a high salinity and is easily precipitated. In the natural state, brine transport in the brine layer is extremely slow, and the brine is in a relatively stable chemical equilibrium state with the rock salt media. However, during mining, both the seepage and the chemical fields fluctuate significantly, thereby disrupting the equilibrium and leading to variations in the chemical composition and dynamic characteristics of the brine. Therefore, we selected underground brine from the Mahai Salt Lake, collecting a total of 183 brine samples over three stages of mining（i.e., the early stage of underground brine extraction, the initial stage of mining, and the later stage of mining）. Using a range of analytical techniques, the chemical dynamics of the underground brine water and its evolution were systematically studied. We found that evaporation and enrichment were the main mechanisms of underground brine evolution in the Mahai Salt Lake, with cation exchange and mineral dissolution/precipitation being key factors in determining the dynamic characteristics and evolution of the brine.

Study on the Isothermal Evaporation Process at 5℃ with the Brine of Laguocuo Salt Lake

1 Introduction Tibet has nurmerous salt lakes.Laguocuo is one of the salt lakes,which is located to the sorthern of Ali Plateau,31°59′02″N-32°04′08″N,84°02′03″E-84°12′03″E.Its lake water is rich in potassium,magnesium,lithium,boron,rubidium,cesium and other resources.The study of

Natural Evaporation of Dangxiongcuo Salt Lake Spring Brine in Tibet,China

1 Introduction Dangxiongcuo salt lake(Figure 1),which is located in the southwest of Tibet,China,is rich in valuable mineral elements like lithium,potassium,boron,rubidium,caesium

Production of Potash and N-Mg Compound Fertilizer via Mineral Shoenite from Kunteyi Salt Lake:Phase Diagrams of Quaternary System(NH_(4))_(2)SO_(4)-MgSO_(4)-K_(2)SO_(4)-H_(2)O in the Isothermal Evaporation and Crystallization Process

Based on the requirement of the new technology for producing potassium sulfate and N-Mg compound fertilizer,boussingaultite,by the reaction of the mineral shoenite from Kunteyi Salt Lake,Qinghai province,and the industrial by-product ammonium sulfate,the solubilities of the quaternary system(NH_(4))_(2)SO_(4)-MgSO_(4)-K_(2)SO_(4)-H_(2)O at 25.0℃in the isothermal evaporation and crystallization process were measured using the isothermal evaporation method,and the corresponding phase diagrams were plotted.According to the diagram,this system contains six saturation points and six solid phase fields of crystallization,which correspond to(K1-m,(NH_(4))m)_(2)SO_(4),(NH_(4))_(2)SO_(4)·MgSO_(4)·6H_(2)O,K_(2)SO_(4)·MgSO_(4)·6H_(2)O,MgSO_(4)·6H_(2)O,(K1-n,(NH_(4))n)_(2)SO_(4)·MgSO_(4)·6H_(2)O and MgSO_(4)·7H_(2)O,respectively.By analyzing and calculating the isothermal evaporation and dissolution phase diagram of this quaternary system at 25.0℃,K_(2)SO_(4)and(NH_(4))_(2)SO_(4)·MgSO_(4)·6H_(2)O can be separated via K_(2)SO_(4)·MgSO_(4)·6H_(2)O and(NH_(4))_(2)SO_(4)as raw materials.Theoretical calculations about the proposed process were carried out and verified by experiment,which indicated that the yield of potassium sulfate was improved and the magnesium resources were fully utilized.

Problems of Lithium Isotope Research in Salt Lake Study

Lithium in nature mainly exists in the forms of solid minerals and ionic liquid.More than 150 lithium minerals exist,which are mainly pegmatite mineral including triphane,lithionite and petalite.Liquid lithium mainly

Hydrochemistry of the Gasikule Salt Lake,Western Qaidam Basin of China

The Qaidam Basin is a large intermontane depression in Qinghai Province,China,which located on the northern margin of the Tibet plateau,and surrounded by the Qilian,Kunlun and Aljun mountains which rise to more than 5000m.Some 27 salt lakes occur within the basin,occupying an area of approximately 1500 km2.Additionally,there are extensive areas of dry playas.Together,the playas and salt lakes cover about one quarter of the total basin area.Whereas the western

盐湖卤水中硼酸盐化学形态及Raman光谱定量分析

我国青藏盐湖以富含硼锂而著称,卤水中硼化学赋存状态随湖水化学类型的不同而发生变化,其中以硫酸盐型盐湖卤水中硼酸盐的存在形式变化最为复杂,卤水蒸发过程一般不以固体盐形式结晶析出,而是以多硼物种形式富集于氯化镁饱和老卤中,表现出严重的过饱和性,对后续锂盐和镁盐的分离提取影响较大。开展盐湖卤水体系中硼酸盐化学形态、分布规律及离子间作用机制等溶液化学研究对盐湖资源高效开发具有重要的意义。相比常规拉曼光谱技术,拉曼积分球基于拉曼散射原理可极大地提高激发光的使用效率和拉曼散射信号,对硼酸盐溶液结构检测具有拉曼响应信号强、检出限低、信噪比高等优点,为盐卤复杂体系硼酸盐化学形态的定量分析奠定了基础。利用拉曼积分球开展了盐湖卤水硼酸盐化学形态研究,阐述了卤水蒸发过程多硼酸根离子的变化规律;同时借助响应曲面法进行实验设计与优化,建立了共存盐类干扰回归模型用于盐湖卤水中单硼物种B(OH)_(3)的准确测定。结果表明,盐湖卤水浓缩过程中硼不断聚合生成多聚度硼酸根离子如B_(3)O_(3)(OH)_(4)^(-)和B_(6)O_(7)(OH)_(7)^(2-)等,硼的化学形态变化规律与碱土金属如MgCl_(2)-MgO-2B_(2)O_(3)-H_(2)O体系中硼物种变化一致,但与碱金属溶液体系物种变化差别较大。回归模型对卤水中正硼酸B(OH)_(3)定量分析的相对误差小于5%,准确度较高;阐明了蒸发浓缩过程中B(OH)_(3)物种分布的变化规律,从定量视角初步阐述了卤水富集过程硼酸根离子间的聚合作用关系,可为后续开展盐卤体系多硼物种分布及作用机制研究提供新思路、新方法。

溶析结晶用于盐湖卤水提钾和镁锂分离研究

采用溶析结晶法快速分离盐湖卤水中氯化钾并降低卤水中的镁锂比,解决青海盐湖盐田摊晒存在的生产周期长、需要修建大面积盐田等难题。以有机溶剂为溶析剂,考察了不同种类溶析剂加入量、溶析温度、溶析时间等对盐湖氯化钾收率及镁锂比的影响。实验结果表明,以无水乙醇为溶析剂与盐湖卤水体积比为2∶1,溶析温度为-15℃,时间为90 min时,氯化钾和氯化钠的收率分别达到93.15%和99.84%。溶析结晶后的母液经过过滤,在70~80℃,以0.5℃/min的降温速率进行动态降温,析出氯化镁晶体,镁锂质量比由原卤中的388.44降低至266.63,最终达到快速分离氯化钾的目的及为后续对镁锂进一步分离提供更有利的条件。

In Search of Portable Water Supplies within a Brine and Mine Water-Invaded Region for Serving Some Communities around Ishiagu, Afikpo and Environs in Abakaliki Basin, Southeast Nigeria

The study investigates the hydrogeochemical characteristics of some towns in the Abakaliki Basin, comprising, Ishiagu, Aka Eze, Amaseri, Afikpo and Okposi communities, with the aim of sourcing for portable water in the area. The basin is underlain by Albian sediments, essentially shales, in the lowlands, which were affected by low-grade metamorphism that had produced slates. The highlands comprise basic intrusives from episodes of magmatism and metallic ore mineralisation. Injection of brines into the aquifer system and low, seasonal aquifer recharge from rainfall results in poor water quality in the area. The study analyzes the geochemical distribution in water sources in the area and identifies sources of pollutants to guide the better choice of portable water. Results of hydrogeochemical analysis of both surface and groundwater from the communities were compared with World Health Organization to identify portable water locations in the area. While the salt lake at Okposi is the main source of brine intrusion in the study area, the Pb/Zn mine at Ishiagu is the main source of mine-water pollution in the study area. Most chemical parameters, (especially Cl-, Na+, Ca2+, Mg2+, SO42-, HCO3-) maintain high concentrations within the salt lake area, with the values declining away from the salt lake. The main anthropogenic source of pollution in the area, especially at Ishiagu, is the indiscriminate surface mining of lead-zinc without proposer waste management practices. Possible sourcing for portable water in the study area includes a deep borehole at Ishiagu, away from lead-zinc intrusives. At the Okposi axis, searching for portable water in boreholes should target shallower aquifers that do not communicate with the deeper-seated brine zones, likewise targeting zones farther away from these brine-invaded areas. A controlled pumping rate could potentially ensure that the cone of depression was not low enough to reach the brine zone at depth. In addition, desalination could also potentially render the salt water drinkable if properly handled to eliminate the high concentration of salts in the water to the level of acceptable limit by the WHO. Based on the study, the best area to target for portable water in the study area is Afikpo, with most geochemical elements naturally occurring within WHO’s standard concentration while portable water could be harnessed in areas further away from mining sites, especially at deep groundwater.

聚酰胺纳滤膜表面羧基密度调控及其抗污染性能

采用均苯三甲酰氯(TMC)、对苯二甲酰氯(IPC)与哌嗪进行界面聚合反应,制备了不同羧基密度的聚酰胺纳滤膜.研究了羧基密度对膜污染的影响,并对纳滤膜的镁-锂分离选择效果进行评估.结果表明,TMC纳滤膜的羧基密度是IPC纳滤膜的3倍,水通量分别为81.9 L/(m^(2)·h·MPa)和56.5 L/(m^(2)·h·MPa).TMC纳滤膜对硫酸镁、氯化钠的截留效果优于IPC纳滤膜,对卤水镁的截留率达82.66%,对锂的截留率为-27.82%,具有较好的镁-锂分离选择效果.膜污染结果显示,TMC纳滤膜的不可逆通量衰减指数是IPC纳滤膜的3倍,抗污染能力与膜面羧基密度成反比.结果证实了膜面羧基官能团在膜污染中的关键作用,为制备具备抗污染性和高镁-锂分离比的纳滤膜提供了新思路.