中国西南滇黔桂关键资源远景新区锂地球化学时空分布特征及找矿预测

锂因其在新能源领域的应用广泛性和不可替代性而备受关注。以往锂矿勘查主要集中于盐湖型和硬岩型锂矿,针对沉积型锂矿开展工作较少。本文聚焦于中国西南滇黔桂地区,以岩石和水系沉积物中锂的时空分布特征为基础,分析区域内沉积型锂矿成矿潜力。结果显示,中国西南滇黔桂地区水系沉积物锂含量平均值为46. 7×10-6,显著高于全国背景值32×10-6。以57. 0×10-6为异常下限,共圈定9个锂地球化学省,与已知的沉积型锂矿床分布具有良好的对应性。同时,锂异常浓集区与某些特定时代和岩性的地层分布密切相关。区内水系沉积物中锂元素含量受到岩石锂含量制约,以碳酸盐岩为主的构造单元水系沉积物中的锂显著次生富集,以陆源碎屑岩为主的构造单元内水系沉积物中锂富集程度较弱。综合分析认为,西南滇黔桂地区锂异常带的形成受区域岩石类型、次生富集作用和气候条件等多重因素制约。该研究对了解西南滇黔桂地区锂元素次生聚集就位机制和指导沉积型锂资源的找矿勘查具有重要的参考意义。     

钢筋混凝土耐久性海洋暴露试验

对不同技术条件的钢筋混凝土试件进行长期的海洋暴露腐蚀试验,以了解其服役特性,为钢筋混凝土结构的耐久性设计提供依据。近7年的暴露结果表明：在混凝土中掺加高炉矿渣等活性掺合料,能大大降低氯离子渗透速率,提高钢筋混凝土的耐久性。     

A comparison of groundwater recharge estimation methods in a semi‐arid,coastal avocado and citrus orchard (Ventura County,California)

We assess the relative merits of application of the most commonly used field methods (soil‐water balance (SWB), chloride mass balance (CMB) and soil moisture monitoring (NP)) to determine recharge rates in micro‐irrigated and non‐irrigated areas of a semi‐arid coastal orchard located in a relatively complex geological environment. Application of the CMB method to estimate recharge rates was difficult owing to the unusually high, variable soil‐water chloride concentrations. In addition, contrary to that expected, the chloride concentration distribution at depths below the root zone in the non‐irrigated soil profiles was greater than that in the irrigated profiles. The CMB method severely underestimated recharge rates in the non‐irrigated areas when compared with the other methods, although the CMB method estimated recharge rates for the irrigated areas, that were similar to those from the other methods, ranging from 42 to 141 mm/year. The SWB method, constructed for a 15‐year period, provided insight into the recharge process being driven by winter rains rather than summer irrigation and indicated an average rate of 75 mm/year and 164 mm/year for the 1984 – 98 and 1996 – 98 periods, respectively. Assuming similar soil‐water holding capacity, these recharge rates applied to both irrigated and non‐irrigated areas. Use of the long period of record was important because it encompassed both drought and heavy rainfall years. Successful application of the SWB method, however, required considerable additional field measurements of orchard ET_c, soil‐water holding capacity and estimation of rainfall interception – runoff losses. Continuous soil moisture monitoring (NP) was necessary to identify both daily and seasonal seepage processes to corroborate the other recharge estimates. Measured recharge rates during the 1996 – 1998 period in both the orchards and non‐irrigated site averaged 180 mm/year. The pattern of soil profile drying during the summer irrigation season, followed by progressive wetting during the winter rainy season was observed in both irrigated and non‐irrigated soil profiles, confirming that groundwater recharge was rainfall driven and that micro‐irrigation did not ‘predispose’ the soil profile to excess rainfall recharge. The ability to make this recharge assessment, however, depended on making multiple field measurements associated with all three methods, suggesting that any one should not be used alone. Copyright © 2000 John Wiley & Sons, Ltd.     

Salt weathering: influence of evaporation rate,supersaturation and crystallization pattern

Micro- and macroscale experiments which document the dynamics of salt damage to porous stone have yielded data which expose weaknesses in earlier interpretations. Previously unexplained differences are found in crystal morphology, crystallization patterns, kinetics and substrate damage when comparing the growth of mirabilite (Na₂SO₄. 10H₂O) and thenardite (Na₂SO₄) versus halite (NaCl). The crystallization pattern of sodium sulphate was strongly affected by relative humidity (RH), while a lesser RH effect was observed for sodium chloride. Macroscale experiments confirmed that mirabilite (crystallizing at RH > 50 per cent) and thenardite (crystallizing at RH < 50 per cent) tend to form subflorescence in highly localized areas under conditions of constant RH and temperature. This crystallization pattern was more damaging than that of halite, since halite tended to grow as efflorescence or by filling the smallest pores of the stone in a homogeneous fashion, a result which contradicts Wellman and Wilson's theoretical model of salt damage. Low RH promoted rapid evaporation of saline solutions and higher supersaturation levels, resulting in the greatest damage to the stone in the case of both sodium sulphate and sodium chloride crystallization. At any particular crystallization condition, sodium chloride tended to reach lower supersaturation levels (resulting in the crystallization of isometric crystals) and created negligible damage, while sodium sulphate reached higher supersaturation ratios (resulting in non-equilibrium crystal shapes), resulting in significant damage. ESEM showed no damage from sodium sulphate due to hydration. Instead, after water condensation on thenardite crystals, rapid dissolution followed by precipitation of mirabilite took place, resulting in stone damage by means of crystallization pressure generation. It is concluded that salt damage due to crystallization pressure appears to be largely a function of solution supersaturation ratio and location of crystallization. These key factors are related to solution properties and evaporation rates, which are constrained by solution composition, environmental conditions, substrate properties, and salt crystallization growth patterns. When combined with a critical review of salt damage literature, these experiments allow the development of a model which explains variations in damage related to combinations of different salts, substrates and environmental conditions. Copyright © 1999 John Wiley & Sons, Ltd.     

锂离子正极材料重点技术专利分析

正极材料是制造锂离子电池的关键材料之一,占据电池成本的25%以上,在锂离子电池中占据核心地位。该文对锂离子正极材料进行专利信息的挖掘和数据分析,通过专利申请趋势、布局、企业专利实力对锂离子正极材料的技术专利展开分析,总结了锂离子正极材料技术的发展、企业专利实力与保护情况。同时对主要用于动力型锂离子电池中的锰酸锂正极材料进行了申请态势、竞争格局、实力排查以及技术主题和技术功效的分析,可为相关研发人员及企业开发外围专利或改进专利提供思路。     

氯化锌/氯化胆碱离子液体单晶合成、表征及性质研究

选用溶剂挥发法,以氯化胆碱和氯化锌为原料,成功合成了一种新型的Zn(Ⅱ)单晶[Ch][ZnCl_3],并采用单晶X射线衍射、红外光谱、X-粉末衍射、元素分析等对单晶结构进行表征。结果表明:该晶体属于单斜晶系,空间点群为P 21/c,晶胞参数a=7.322(4)?,b=9.423(5)?,c=16.688(8)?,V=1145.8(10)?~3,Z=4,C_5H_(14)Cl_3NOZn,Mr=275.89,Dc=1.599 g/cm~3,F(000)=560,m=2.797 mm~(-1),R=0.0524和wR=0.1434。通过热分析,热分解温度为323.5℃,具有较好的热稳定性,熔点为43℃,相变焓为94.1 J·cm~(-3)。     

盐湖氯化镁制备炼钢用镁钙造渣剂的实验研究

本文探讨了盐湖副产氯化镁应用于炼钢冶金造渣的可行性。以盐湖水氯镁石和石灰为原料,通过化学合成制备了氧化镁,再将氧化镁与石灰、粘结剂混配成型制备炼钢用镁钙造渣剂,考察了粘结剂硼酸的不同用量时造渣剂形成的球团强度和抗压强度及微观结构变化;同时研究了不同煅烧温度、煅烧时间、氧化镁掺杂量的情况下,造渣剂的活性及杂质脱除率。实验结果表明,利用该方法制备的镁钙造渣剂应用于钢铁冶金造渣过程,可有效地脱除碳、磷、硫、硅等杂质成分,提高转炉冶炼的冶金效果的同时实现了盐湖资源再利用,具有较好的推广应用前景。     

浓氯化钙水溶液中高配位Ca-Cl离子团簇:分子动力学模拟研究

采用分子动力学(MD)模拟研究了5.55 mol·kg~(-1)氯化钙溶液的微观结构特征,尤其是溶液中高配位Ca-Cl离子团簇的结构与性质,探究了温度对于高配位Ca-Cl离子团簇的影响。结果显示,5.55 mol·kg~(-1)氯化钙溶液中,除形成[CaCl]~+、[CaCl_2]~0离子对外,还存在一些高配位[CaCl_x]~(2-)~x(x=3～6)离子团簇。高配位[CaCl_x]~(2-)~x(x=3～6)离子团簇在5.55 mol·kg~(-1)氯化钙溶液中介稳存在,易解离或进一步缔合形成更大Ca-Cl离子团簇,这可能与溶液中大量未完全水合Ca~(2+)对高配位[CaCl_x]~(2-)~x(x=3～6)离子团簇水壳层的扰动破坏有关。温度升高,氯化钙溶液中Ca-Cl离子缔合增强,但高配位Ca-Cl离子团簇的平均存在时间(t_(av))减小,这表示高温下溶液中Ca-Cl离子团簇频繁地解离与缔合,离子团聚趋势更为显著。本工作观测到的高配位[CaCl_x]~(2-)~x(x=3～6)离子团簇可能是浓氯化钙溶液Ca-Cl离子缔合过程中一种热力学不稳定结构,但这些高配位Ca-Cl离子团簇的形成可能对溶液结晶及相关化学过程产生不利影响。     

LiTFSI0.6-LiODFB0.4+LiPF6电解液在锂金属电池中的应用

锂金属因为其具有高能量密度,是构建高比能电池的理想负极。然而,锂枝晶的产生和生长阻碍了锂金属电池(锂作为负极)的发展。在本文中,我们使用LiPF_6作为LiTFSI-LiODFB基双盐电解液的添加剂,该电解液能够显著提高锂金属电池在25℃和60℃温度下的循环稳定性和倍率性能。锂金属电池的优异的循环性能归因于添加剂能够在Li金属表面上产生稳定的固体电解质膜。     

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。