Hydrochemical Characteristics and Evolution of Underground Brine in Lop Nur,Northwestern China

Lop Nur is located at the eastmost end of the Tarim Basin in Xinjiang,Northwestern China.This study reviews the hydrochemical characteristics and evolution of underground brine in Lop Nur,based on analytical data from 429 water samples(mainly brine).It is found that in the NE-SW direction,from the periphery to the Luobei sub-depression,while the hydrochemical type varies from the sodium sulfate subtype(S)to the magnesium sulfate subtype(M),the corresponding brine in the phase diagram transfers from the thenardite phase(Then)area,through the bloedite phase(Blo),epsomite phase(Eps),picromerite phase(Picro),finally reaching the sylvite phase(Syl)area.As for the degree of evolution,the sequence is the periphery<Luobei horizontally and the overlying glauberite brine<the underlying clastic brine vertically.It is concluded that the oxygen and hydrogen isotopic compositions of the brine have evidently been affected through the effects of evaporation and altitude,as well as the changes in local water circulation in recent years.Boron and chloride isotopic compositions show that the glauberite brine is formed under more arid conditions than the clastic one.The strontium isotopic composition indicates that the Lop Nur brine primarily originates from surface water;however,deep recharge may also be involved in the evolution of the brine,according to previous noble gas studies.It is confirmed that the brine in Lop Nur has become enriched with potassium prior to halite precipitation over the full course of the salt lake's evolution.Based on chemical compositions of brine from drillhole LDK01 and previous lithological studies,the evolution of the salt lake can be divided into three stages and it is inferred that the brine in Lop Nur may have undergone at least two significant concentration-dilution periods.

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.

Synergetic Control of Li^(+)Transport Ability and Solid Electrolyte Interphase by Boron-Rich Hexagonal Skeleton Structured All-Solid-State Polymer Electrolyte

High Li^(+)transference number electrolytes have long been understood to provide attractive candidates for realizing uniform deposition of Li^(+).However,such electrolytes with immobilized anions would result in incomplete solid electrolyte interphase(SEI)formation on the Li anode because it suffers from the absence of appropriate inorganic components entirely derived from anions decomposition.Herein,a boron-rich hexagonal polymer structured all-solid-state polymer electrolyte(BSPE+10%LiBOB)with regulated intermolecular interaction is proposed to trade off a high Li^(+)transference number against stable SEI properties.The Li^(+)transference number of the as-prepared electrolyte is increased from 0.23 to 0.83 owing to the boron-rich cross-linker(BC)addition.More intriguingly,for the first time,the experiments combined with theoretical calculation results reveal that BOB^(-)anions have stronger interaction with B atoms in polymer chain than TFSI^(-),which significantly induce the TFSI^(-)decomposition and consequently increase the amount of LiF and Li3N in the SEI layer.Eventually,a LiFePO_(4)|BSPE+10%LiBOBlLi cell retains 96.7%after 400 cycles while the cell without BC-resisted electrolyte only retains 40.8%.BSPE+10%LiBOB also facilitates stable electrochemical cycling of solid-state Li-S cells.This study blazes a new trail in controlling the Li^(+)transport ability and SEI properties,synergistically.

Construction of truncated-octahedral LiMn2O4 for battery-like electrochemical lithium recovery from brine

The extraction of lithium from salt lakes or seawater has attracted worldwide attention because of the explosive growth of global demand for lithium products. The LiMn_(2)O_(4)-based electrochemical lithium recovery system is one of the strongest candidates for commercial application due to its high inserted capacity and low energy consumption. However, the surface orientation of LiMn_(2)O_(4)that facilitates Li diffusion happens to be prone to manganese dissolution making it a great challenge to obtain high lithium inserted capacity and long life simultaneously. Herein, we address this problem by designing a truncated octahedral LiMn_(2)O_(4)(Tr-oh LMO) in which the dominant(111) facets minimize Mn dissolution while a small portion of(100) facets facilitate the Li diffusion. Thus, this Tr-oh LMO-based electrochemical lithium recovery system shows excellent Li recovery performance with high inserted capacity(20.25 mg g^(-1)per cycle) in simulated brine. In addition, the dissolution rate of manganese per 30 cycles is only 0.44% and the capacity maintained 85% of the initial after 30 cycles. These promising findings accelerate the practical application of LiMn_(2)O_(4)in electrochemical lithium recovery.

Construction of porous disc-like lithium manganate for rapid and selective electrochemical lithium extraction from brine

In order to satisfy the growing global demand for lithium, selective extraction of lithium from brine has attracted extensive attention. LiMn_(2)O_(4)-based electrochemical lithium recovery system is one of the best choices for commercial applications because of its high selectivity and low energy consumption.However, the low ion diffusion coefficient of lithium manganate limits the further development of electrochemical lithium recovery system. In this work, a novel porous disc-like LiMn_(2)O_(4) was successfully synthesized for the first time via two-step annealing manganese(Ⅱ) precursors. The as-prepared LiMn_(2)O_(4) exhibits porous disc-like morphology, excellent crystallinity, high Li^(+)diffusion coefficient(average 7.6×10^(-9)cm^(2)·s^(-1)), high cycle stability(after 30 uninterrupted extraction and release cycles, the crystal structure hardly changed) and superior rate capacity(93.5% retention from 10-120 mA·g^(-1)). The porous structure and disc-like morphology further promote the contact between lithium ions and electrode materials. Therefore, the assembled electrochemical lithium extraction device with LiMn_(2)O_(4) as positive electrode and silver as negative electrode can realize the rapid and selective extraction of lithium in simulated brine(adsorption capacity of lithium can reach 4.85 mg·g^(-1) in 1 h). The mechanism of disc-like LiMn_(2)O_(4) in electrochemical lithium extraction was proposed based on the analysis of electrochemical characterization and quasi in situ XRD. This novel structure may further promote the practical application of electrochemical lithium extraction from brine.

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.

四川盆地三叠系气田型深层富钾锂卤水勘探历程、进展与展望

四川盆地三叠系嘉陵江组和雷口坡组不仅是常规天然气的主要赋存层位,同时也形成和储存了富含钾锂等关键元素的卤水资源。本文梳理总结了四川盆地三叠系气田型深层卤水勘探进程、成因机理、富集规律方面的进展和认识,并对潜在的研究重点进行了展望。四川盆地三叠系气田型深层卤水中钾、锂等关键金属元素均达到了工业品位,随着全球对锂资源需求的增大,由起初的“气钾兼探”逐渐向“气钾锂综合勘探”过渡。四川盆地三叠系深层富钾锂卤水的成因机制大体上相同,其中干旱气候条件下古海水的蒸发浓缩致使卤水中的钾锂富集;高温高压下含钾/锂元素的杂卤石/绿豆岩与埋藏卤水发生水岩反应,进一步促进了钾锂的富集;淋滤作用也是卤水中钾元素富集的重要成因。深层卤水主要储集于各类白云岩中,其富集主要受断裂、裂缝发育带和背斜等构造控制,富集规律可归纳为“孔隙裂缝储卤、断裂运卤、背斜核部富卤”。基于目前四川盆地气田型深层卤水的勘探现状和不足,未来应该加强地球物理勘探集成新技术的研发、资源评价方法与体系的优化、含高品位伴生元素新层系的勘探以及气田型卤水有效开发利用技术的研究。未来有望在四川盆地气田型深层卤水继续取得新的找矿突破。

从高钙富硼老卤中提硼研究

以青海某高钙富硼老卤为研究对象开展了提硼研究。结果表明,合适的萃取条件为:磺化煤油为稀释剂、异辛醇用量50%、萃取相比1.0、萃取混合时间15 min;合适的反萃条件为:反萃剂为pH=1的稀盐酸、反萃相比1.5、反萃混合时间15 min。以此条件在5级混合澄清槽中完成了连续逆流萃取—反萃运转试验,连续运转45 h,硼萃取率为95.49%,硼与钾、钠、钙、镁的分离效果较好;硼反萃率为99.59%,反萃液中硼含量达17.17 g/L。采用“溶剂萃取—反萃—高温蒸发—低温冷却结晶—重溶—冷却结晶—过滤洗涤—干燥”工艺高效分离提取硼,硼总回收率为92.33%,制备出的硼酸产品达国家标准(GB/T 538—2018)要求。

南翼山深部卤水蒸发结晶过程中铵、钾共析行为研究

高铵卤水的蒸发过程中通常会形成掺杂NH+4的钾石盐和光卤石等含铵盐类。固溶体或复盐被用于解释铵和钾在光卤石中的共析出现象。然而,NH_(4)^(+)进入光卤石矿床的机制一直未得到更好的理解。重新审视这一问题,对于深入了解蒸发岩中NH+4的地球化学行为具有重要意义。本研究从相平衡实验和热力学建模方面重新审视了KCl+NH_(4)Cl+MgCl_(2)+H_(2)O四元体系中光卤石(推测是KMgCl_(3)·6H_(2)O、NH_(4)MgCl_(3)·6H_(2)O、K_(2)NH_(4)Mg_(3)Cl_(9)·18H_(2)O、KNH_(4)Mg_(2)Cl_(6)·12H_(2)O和光卤石型固溶体)与水相的平衡。此外,对南翼山地下卤水进行室温蒸发实验,并与相平衡结果进行比较。本文模拟和实验结果均显示在298.15 K时该体系会形成富钾和富铵两种类型的光卤石固溶体,不形成纯盐相KCl、NH_(4)Cl及复盐相KMgCl_(3)·6H_(2)O和NH_(4)MgCl_(3)·6H_(2)O。南翼山卤水实际蒸发实验、相平衡实验和模型模拟结果一致,表明南翼山深部卤水蒸发过程形成了富含铵的光卤石固溶体,而不是新的光卤石型复盐。本文研究结果对于南翼山深部卤水钾资源开发利用提供了基础理论支撑。

四川盆地东北部黄金口背斜三叠系富K、Li和B卤水成因和演化

四川盆地东北部地区三叠系嘉陵江组四、五段—雷口坡组一段赋存丰富的卤水资源,卤水中富集K、Li、B等元素,具有潜在的开发利用价值。长期以来,一般认为川东北三叠系中卤水因溶解地层中的钾盐矿物而富集K物质,但这一认识并没有得到确证,此外,对卤水中Li和B的成因和演化鲜有报道。本文以川东北三叠系深层卤水为研究对象,以地球化学和稳定同位素分析为主要方法,运用聚类分析对比采自13口钻井卤水的地球化学数据。与海水相比,区内深层卤水中的K^(+)、Ca^(2+)、Li和B明显富集,而Mg^(2+)和SO_(4)^(2-)则相对亏损。卤水的^(87)Sr/^(86)Sr和δ^(34)S值均与卤水储层的^(87)Sr/^(86)Sr和δ^(34)S值相一致,进一步说明深层卤水为海水原地蒸发浓缩形成。Q型聚类分析表明,北2井和川宣地1井的卤水化学组分相似,川25井、ZK601井、恒成1井、恒成3井的卤水化学组分相近,证明川25井和ZK601卤水中K的富集是由于卤水溶解了地层中的钾盐矿物(杂卤石)。白云岩化导致了卤水中Ca^(2+)明显富集,而Mg^(2+)明显亏损,地层中赋存的硫磺和H_(2)S证明了大量硫酸被还原,使得SO_(4)^(2-)出现明显亏损。还原作用不仅导致卤水和石膏δ^(34)S的升高,而且引起了区域内石膏和卤水的δ^(34)S高于同时期海水的δ^(34)S值。嘉陵江组沉积晚期,三江地区流纹质火山岩浆喷发产生了大量携带含Li和B元素的气体和热液载体,进而被搬运至蒸发盐盆中。火山热液和气体中的Li、B具有相对较低的δ^(7)Li值和δ^(11)B值,在提升卤水中Li和B含量的同时,也降低了卤水δ^(7)Li值和δ^(11)B值,使得其低于正常海水的δ^(7)Li值和δ^(11)B值。

基于连续小波变换的黑北凹地砂砾储卤层沉积特征研究

柴达木盆地西部中深层“砂砾型”钾盐储卤层与沉积水体变化息息相关,高密度网状二维地震资料包含的频率信息,有助于识别发育砂砾储卤层的沉积环境,为深层富钾卤水储层研究提供支撑。采用连续小波变换时频分析技术将地震信号从一维的时间域拓展到二维的时间-频率域上,能够在频谱中更清晰地刻画沉积体内部岩性组合的旋回结构特征。基于正演数据和实际钻井数据,总结了低水位体系域、水进体系域、高水位体系域和水退体系域层序框架下,沉积体的地震时频谱旋回响应特征:低水位体系域的时频谱能量主要聚集在低频,高水体系域的时频谱能量主要聚集在高频,水进体系域的时频谱能量随时间减小向高频方向移动,水退体系域的时频谱能量随时间减小向低频方向移动,指出35 Hz是划分有利沉积旋回——水退体系域末期、低水位体系域和水进体系域初期的频率阈值。选择合适频率区间重构地震数据能突出弱振幅砂砾层的反射特征,结合全频带数据有助于快速识别有利沉积旋回,为寻找砂砾型深层卤水钾矿提供依据。

柴达木盆地卤水钾盐迁聚规律与找矿新突破

钾盐是我国大宗紧缺战略性“粮食”矿产,对保障国家粮食安全具有重要意义。我国钾盐资源具有需求量大、对外依存度高等特点,寻找新的钾盐矿床、形成新的大型钾盐资源基地刻不容缓。2023年,中国地质调查局组织开展青海柴达木盆地钾盐“增储保供”地质调查工作,在前期对柴达木盆地成盐聚钾规律性认识的基础上,于柴西北大浪滩—黑北凹地部署实施了“探采一体化”柴钾1井,钻获1021.95 m(井深111.54~1133.49 m)巨厚松散砂砾储卤层,全井段抽卤试验获日稳定涌水量8586 m^(3)/d、水位降深11.3 m、单位涌水量759.89 m^(3)/d·m、氯化钾平均含量为0.54%的高产工业品位“砂砾型”卤水钾矿,取得了柴达木盆地陆相深层卤水钾盐找矿新突破,为形成中国新的亿吨级大型钾盐基地夯实了资源基础。

卤水表面附近盐岩结晶特征研究

【目的】为了弥补现代盐湖沉积考察中丢失的信息,获取盐岩动态结晶过程,指导古盐湖沉积研究。【方法】借助室内石盐蒸发实验,观察卤水蒸发过程中氯化钠结晶特征,分析石盐结晶与沉积环境之间的关系,为盐湖沉积模式建立提供参考。【结果与结论】石盐沉积位置受结晶习性影响,晶体可以在卤水界面之上沉积,其形成的动力除了蒸发泵作用外,还受空气湿度和石盐潮解共同控制;人字晶一般形成于漏斗晶基础之上,在发育空间受限时,绕不同漏斗晶核生长的纹层斜交后形成人字晶纹,两种晶型可以同时沉积于水面之上;盐湖干涸之前,可能经历岩层封锁水面的现象,并可能对临层的碎屑沉积物产生影响。

卤水提锂多元新路径:技术、资源、环境和成本

传统沉淀法提锂生产周期长、不适用于低锂浓度卤水,盐湖提锂产量增长缓慢,难以满足新能源产业发展的需求。因此,开发高镁锂比卤水提锂新技术是锂产业发展的迫切需求。本文概述了吸附法、萃取法、膜法和电化学法等提锂新工艺的研究现状,发现铝基吸附剂已应用于工业生产,但其吸附容量显著地小于锰基和钛基吸附剂,而后两者的溶损和长吸附平衡时间是制约其产业化的关键。中性磷类萃取剂关注最多,但其易腐蚀和出现第三相;酰胺类萃取体系无腐蚀,已用于氯化物型卤水工业化提锂,但其稳定性需长期关注;并且萃取法工艺流程较长,酸碱消耗高。膜法无法深度除镁,需与其他方法相结合提锂,其水资源消耗量大。电渗析和“摇椅式”电化学实现了连续性提锂,加速了吸附速率,避免了洗脱剂的使用,其电耗随着优化提锂体系和工作条件的降低,电化学提锂将迎来广阔的产业前景。以上卤水提锂新工艺资源消耗和环境影响小于传统沉淀法,对高镁锂比盐湖具有显著的竞争优势,但各有弊端。因此,未来盐湖卤水提锂应加强多种新技术的集成与耦合,前移提锂过程,提升全流程锂的回收率和多种资源的综合开发。

温度影响下罗布泊盐岩路基填料变形特性研究

为探明温度影响下盐岩路基填料变形特性,保障盐岩路基稳定性,促进盐岩在路基工程中资源化应用,全面分析了卤水及盐岩相变特征,基于正交试验方法探究了单次降温多因素交互作用下盐岩填料的变形规律,系统研究了多次冻融循环后盐岩填料盐胀累积规律,并基于试验段现场监测综合评价了盐湖区盐岩路基变形特征。结果表明:不同浓度卤水降温曲线均未出现明显过冷阶段,其降温曲线平衡及波动维持时间极为短暂,同时卤水相变温度随浓度增加而升高。盐岩填料的降温曲线存在显著的过冷及温度跳跃阶段,其相变温度随拌和卤水浓度增加而下降。单次降温作用下盐岩填料变形量介于-0.09~0.18 mm,各因素对盐岩填料变形的影响顺序为:上覆荷载>含卤水率>最大粒径>压实度。冻融循环作用下拌合卤水浓度越低,盐岩填料盐胀量越大;上覆荷载对盐岩填料盐胀抑制作用较强。实体工程现场监测表明随着监测时间增长盐岩路基变形呈现正弦波式周期性变化,且变形沿深度方向呈减小趋势,同时盐岩路基变形与温度具有较强的线性相关性。

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。

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.

造粒的氮掺杂碳纳米管基吸附剂对卤水中硼的吸附行为与机理

盐湖卤水中硼资源丰富,存在形式复杂多样,分离和回收硼的意义重大。基于N掺杂强静电与多羟基协同作用能够有效提高硼阴离子的分离机制,设计以水合肼为N源,多羟基的一维纳米材料碳纳米管(CNTs)为多羟基络合基,采用简单的一锅水热法合成了N掺杂的碳纳米管硼吸附材料(N-CNTs)。此外,以改性的聚丙烯腈为造粒剂,经造粒后,最大硼吸附容量为20.45 mg/g,特别在低浓度硼的分离中表现出优异的性能,这使N-CNTs成为硼的高效吸附材料。吸附机理为一维碳纳米管和改性聚丙烯腈的高比表面积上多羟基与N掺杂位置发生强静电协同增强络合吸附。硼吸附过程符合朗格缪尔吸附等温模型和准二阶动力学模型,在高浓盐多离子溶液中表现出优异的选择性硼吸附性能。该吸附剂在东台吉乃尔盐湖卤水中硼的吸附容量达18.92±1 mg/g,该技术在盐湖卤水及水处理行业具有较高的应用潜力。

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。

我国盐穴地下储库建设的挑战与对策研究——从“金坛模式”到“XX模式”

我国盐穴地下储库建设起源于江苏金坛盐矿并获得成功,初步构建了我国盐穴储库建设首个技术标准体系。但是,我国各地盐矿的品位、埋深、矿层厚度和夹层特性等地质条件与金坛盐矿相差甚远,盐穴储库建设面临诸多挑战,不能照搬“金坛模式”。着眼于盐穴储库地质设计、造腔工程、注气排卤方案等方面,首先总结盐穴储库建库的“欧美模式”,以及基本上借鉴“欧美模式”发展形成的我国“金坛模式”的基本特征,然后结合我国已开展和正在开展的其他多座盐矿的盐穴储库建设的研究和工程实践,提出几种基于“一地一议、因矿制宜”原则的典型盐穴储库建库的“XX模式”。“XX模式”意味着是不同于金坛模式并有极大突破和变革的新型建库模式,是应对我国各地盐矿地质复杂性所带来挑战的技术方案和新思路。最后,对于下一步应对盐矿复杂地质条件带来的挑战需要突破和创新的关键理论和技术进行了展望。