当雄错盐湖卤水提钾盐田日晒工艺扩大试验研究

西藏现代钾锂硼特种盐湖的钾盐开发将对我国钾盐需求形成有利补充。本文首次采用蒸发结晶、分步分离的方法,进行了当雄错盐湖碳酸盐型卤水提钾多级盐田日晒工艺扩大试验研究。通过对卤水蒸发析盐全过程做化学分析和物料衡算,确定了钾、硼等重要无机元素的成盐类型和析盐阶段,以及锂、铷等稀有元素的富集规律,最终获得了较高品位钾混盐和高浓母卤,并取得了大量第一手数据资料,为今后实现当雄错盐湖卤水钾盐资源的产业化开发提供了切实可靠的中试基础和设计参考。     

盐湖卤水蒸发浓缩过程中pH值变化规律研究

实验测定了当雄错、一里坪和多格错仁3个盐湖卤水蒸发浓缩过程中pH值,结果发现卤水浓缩过程中pH值表现趋酸向变化或越碱向变化规律;卤水中氯化钠、硫酸钠和水等大量中性成分随浓缩进行不断减少,则强酸弱碱盐或强碱弱酸盐在体系中所占比例越来越大,其水解推动pH值规律性变化;上述3个盐湖卤水浓缩时pH值变化试验数据反映的规律表明,据卤水化学组成配盐结果,可预先判断浓缩过程中pH值变化趋向;氯化物型和硫酸镁亚型盐湖卤水蒸发浓缩时pH值表现逐渐下降的规律,碱金属的碳酸盐或硼酸盐占较大比例的盐湖卤水蒸发浓缩时pH值表现逐渐上升规律;卤水浓缩过程中pH值变化规律对盐湖资源开发研究具有指导作用。     

盐卤硼酸盐化学——Ⅵ.扎仓茶卡盐湖卤水的蒸发和盐类的分离提取

扎仓茶卡盐湖是藏北地区具有经济开发远景的一个新类型硼酸盐盐湖。卤水在25℃蒸发浓缩过程中的析盐顺序符合"介稳相图"预示的结果。结合湖区地表卤水和晶间卤水化学组成,提出该盐湖卤水利用天然冷冻析出芒硝,利用夏季组成卤水日晒分离软钾镁矾,冬季析硝卤水日晒析出钾石盐的自然处理工艺,同时论述了加酸处理含硼浓缩卤水提取硼酸的原则流程。     

硫酸镁亚型盐湖卤水高温蒸发析盐结晶规律（英文）

针对青海大浪滩盐湖区硫酸镁亚型盐田卤水进行了高温蒸发结晶规律的研究,结果表明该盐田卤水在102~122℃高温蒸发时析盐顺序为:MgSO4·H2O、NaCl、MgSO4·6H2O、KCl·MgCl2·6H2O和其他混盐.通过对不同温度下的液相组分分析和固相X射线衍射分析表明,利用高温蒸发开采此种卤水时,最适宜的蒸发温度应控制在117℃左右.此时,该卤水组成中SO2-4的质量分数低于2%,同时K+还未析出,可以简化为Na+,K+,Mg2+//Cl-—H2O四元体系,以便达到开采氯化钾的工艺需求,为该盐湖卤水的综合开发利用提供理论参考.     

五元体系Li+/Cl-,CO2-3,SO2-4,B4O2-7-H2O 298 K相关系实验研究

青藏高原盐湖富含锂、钠、钾的氯化物、硫酸盐、碳酸盐和硼酸盐,尤以其高锂、硼而闻名于世….这些盐湖卤水大多属于Li+,Na+,K+,Mg2+/Cl-,SO2-4,CO32-,Borate-H2O体系.在卤水蒸发浓缩后期,由于绝大部分钠盐、钾盐均已结晶析出,所以卤水的化学组成实际变成Li+,Mg2++/Cl-,SO2-4,CO2-3,Borate-H2O体系.这种复杂水盐体系相关系的研究对于制定从天然卤水中提取稀有元素锂、硼的工艺过程,阐明含锂盐湖的形成和演化规律都有十分重要的意义,是乔必不可少的基础性研究工作.     

盐卤硼酸盐化学(Ⅰ)——含硼盐卤天然蒸发过程中硼酸盐的行为

在进行青藏高原某硼酸盐盐湖卤水的天然蒸发实验中确定,该卤水的蒸发析盐顺序不是按平衡溶解度相图,而是按“太阳相图”预示的亚稳过程进行。从天然蒸发过程中盐卤的浓缩倍数与浓缩卤水中硼富集倍数的一致性认为,盐卤在天然蒸发浓缩析盐过程中硼酸盐并不以固体盐形式析出,而是被赋存于浓缩卤水中。     

多格错仁盐湖卤水冷冻、日晒两步法浓缩制卤研究

藏北无人区的多格错仁盐湖水化学类型为氯化物型,该湖水钾、锂资源品位好;结合自然条件制定该低矿化度卤水在高寒区冬季制卤工艺路线。通过冷冻、日晒两步法成功制得了富含钾、锂的精制卤水;对硫酸钙在该卤水蒸发过程中的过饱和溶解度与石膏缓析现象进行了解析。     

五元体系Li~ /Cl~-,CO_3~(2-),SO_4~(2-),B_4O_7~(2-)-H_2O298K相关系实验研究

青藏高原盐湖富含锂、钠、钾的氯化物、硫酸盐、碳酸盐和硼酸盐,尤以其高锂、硼而闻名于世[1]。这些盐湖卤水大多属于Li ,Na ,K ,Mg2 /Cl-,SO42-,CO32-,Borate-H2O体系。在卤水蒸发浓缩后期,由于绝大部分钠盐、钾盐均已结晶析出,所以卤水的化学组成实际变成Li ,Mg2 /Cl-,SO42-,     

盐湖资源开发利用进展

本世纪头十年里,国际上再度掀起盐湖资源开发热潮。这很大程度上是由于锂的开发热带动的,同时也是和钾肥的广泛施用、价格一路走高有关。南美安第斯高原地区盐湖蕴藏世界70%以上的锂资源,且卤水锂、钾、硼浓度高。该地区极度干旱,少雨多风,非常适合采用卤水盐田蒸发的节能浓缩工艺技术。老的盐湖开发企业则在钾肥需求的带动下,稳步发展。在我国,新疆罗布泊和青海柴达木盆地盐湖则钾锂镁硼产品多元化,经营多元化取得长足进步。本文对近十年来,国内外盐湖开发的新动向做了概括介绍,特别着重于南美"锂三角"地区这一新的生长点。     

硫酸盐型盐湖卤水天然制取软钾镁矾

根据我国盐湖的自然气候条件和资源特点,以Na、K、Mg/Cl、SO_4-H_2O五元体系25℃介稳相图为依据,提出了一条经调节卤水组成后,藉盐田天然日晒蒸发获得软钾镁矾的新工艺途径。文中给出了在窒内于模拟野外条件下进行实验的结果。过程中钾的回收率可达80％以上。     

五元交互体系Li+,Na+,K+//CO32-,Cl--H2O在298.15K的相平衡研究

针对西藏扎布耶盐湖卤水组成,采用等温溶解平衡法研究了五元交互体系Li+,Na+,K+//CO32-,Cl--H2O于298.15K时的相平衡,并绘制了相图(空间立体图和Li2CO3饱和的投影图).结果表明,该五元体系相图含有7个结晶区、13条单变量线和4个无变量点.7个结晶区由6个单盐结晶区和1个复盐结晶区组成,分别为LiCl·H2O,NaCl,KCl,Li2CO3,K2CO3·3/2H2O,Na2CO3·10H2O和NaKCO3·6H2O,没有形成固溶体和天然碱(Na2CO3·NaHCO3·2H2O).4个无变量点标记成K1,K2,K3和K4,所对应的平衡固相盐分别是:Li2CO3+NaKCO3·6H2O+Na2CO3·10H2O+KCl,Li2CO3+NaKCO3·6H2O+K2CO3·3/2H2O+KCl,Li2CO3+NaCl+KCl+LiCl·H2O和Li2CO3+NaCl+Na2CO3·10H2O+KCl.     

四元交互体系Li+，K+/CL-，CO2-3-H2O在298 K时相平衡及物理化学性质研究

Zabuye Saline Lake, Tibet, China, is unrivalled in the world for its very high salinity, in particular, for the very high concentration of ions of lithium, potassium, and boron in the brine. It belongs to alkaline and carbonate-borate-type salt lake. As a part of the study on phase equilibrium of the 6component subsystem Li+, Na+, K+/C1-, CO2-3, B4O2-7-H2O of the brine system, a study on the reciprocal quaternary system Li+, K+/C1-, CO32-H2O at 298 K was done with isothermal dissolution equilibrium method in the present work. The phase equilibrium of the reciprocal quaternary system Li+,K+/C1, CO2-3-H2O at 298 K was studied with isothermal dissolution method in this work. The physicochemistry properties of the corresponding equilibrium solutions such as densities, viscosities, refractive index, conductivities and pH value were determined. The dried salt diagram of the system consists of four crystallization fields (KC1, Li2CO3, LiCI·H2O, K2CO3·3/2H2O) and five isothermal solubility curves.There are no double slat or solid solution found. Pitzer′s model of the electrolyte solution theory was used for parameterization from the results of solubility determination for subsystems and the prediction of solubilities for the reciprocal quaternary system was made. The solubility data of the experiment are in agreement with those calculated.     

273 K下Na2CO3-Na2SO4-Na2B4O7-H2O四元体系介稳相平衡的实验研究

采用等温蒸发法研究了四元体系Na2CO3-Na2SO4-Na2B4O7-H2O在273 K时的介稳相平衡及平衡液相的密度. 利用溶解度数据绘制了该四元体系273 K下的相图. 研究结果表明, 该四元体系有异成分复盐2Na2SO4·Na2CO3形成. 相图中有2个共饱点、5条单变量曲线和4个结晶相区. 4个结晶相区分别为盐Na2CO3·10H2O, Na2SO4·10H2O, Na2B4O7·10H2O和2Na2SO4·Na2CO3的结晶区. 复盐2Na2SO4·Na2CO3同时存在于包含Na2CO3-Na2SO4-H2O三元体系的其它四元体系或高元体系中. 在273 K介稳平衡相图中, 碳酸钠以Na2CO3·10H2O形式析出; 硫酸钠以Na2SO4·10H2O的形式析出; 硼酸钠的完整分子式为Na2B4O5(OH)4·8H2O. Na2CO3对Na2B4O7有盐析作用.     

Li＋,Na＋∥,CO32－,B4O72－-H2O 四元交互体系288 K的相平衡

采用等温溶解平衡法对Li＋,Na＋∥,CO32－,B4O72－-H2O四元体系进行288 K相平衡研究.结果表明,该体系属简单共饱型，在288 K等温溶解度相图中有二个共饱点，五条单变量曲线，平衡固相为Na2CO3•10H2O， Li2B4O7•3H2O，Na2B4O7•10H2O, Li2CO3.     

Na+, K+, Mg2+∥Cl-, SO2-4-H2O五元体系35 ℃介稳相图研究

研究得出（Na+, K+, Mg2+∥Cl-, SO2-4-H2O）五元体系35 ℃时的介稳溶解度数据,绘制了该体系35 ℃的介稳相图,共有9个为氯化钠所饱和的结晶区域：氯化钾、钾芒硝（3K2SO4*Na2SO4）、钾镁矾（K2SO4*MgSO4*4H2O）、钾盐镁矾（KCl*MgSO4*2.75H2O）、光卤石（KCl*MgCl2*6H2O）、白钠镁矾（Na2SO4*MgSO4*4H2O）、硫酸钠、六水硫酸镁（MgSO4*6H2O）和水氯镁石（MgCl2*6H2O）. 所得35 ℃介稳相图与Vant Hoff 25 ℃稳定相图比较有较大区别：软钾镁矾（K2SO4*MgSO4*6H2O）、七水硫酸镁、五水硫酸镁及四水硫酸镁结晶区域消失,钾镁矾和钾盐镁矾结晶区域显著扩大. 所得35 ℃介稳相图与25 ℃介稳相图区别很大：软钾镁矾和七水硫酸镁结晶区域消失,同时出现了钾镁矾和钾盐镁矾的结晶区域. 在该五元体系35 ℃介稳相平衡研究中发现析出的是钾盐镁矾的低水化合物（KCl*MgSO4*2.75H2O）.     

Na+, K+//Cl-, B4O2-7-H2O四元体系273 K介稳相平衡

采用等温蒸发法研究了四元体系Na+, K+//Cl-, B4O2-7-H2O 273 K时的介稳相平衡与相图. 测定了该体系273 K平衡液相中各组分的溶解度及平衡液相的密度; 绘制了该体系的介稳相图. 该四元体系273 K相图由5条溶解度单变量线、4个结晶区及2个共饱和点组成. 体系无复盐或固溶体形成. 四个结晶区分别对应单盐NaCl、KCl、K2B4O7·4H2O 和Na2B4O7·10H2O. 共饱点E1处KCl、NaCl及Na2B4O7·10H2O三盐共饱和,所对应的平衡液相组成为w(Cl-)=29.15%, w(B4O2-7)=0.64%, w(K+)=5.97%, w(Na+)=15.55%; 共饱和点E2处盐KCl、Na2B4O7·10H2O和K2B4O7·4H2O的三盐共饱和, 所对应的平衡液相组成为w(Cl-)=22.84%, w(B4O2-7)=10.98%, w(K+)=28.01%, w(Na+)=1.53%. 同体系298 K时的稳定相图相比, 273 K时硼酸钠的结晶区变大, 而硼酸钾、氯化钠结晶区变小.     

Experimental Study on Phase Equilibria in Na2B4O7–Na2SO4–H2O and Li2B4O7–Na2B4O7–H2O Aqueous Ternary Systems at 273 K

Russian Journal of Physical Chemistry A - The solubility data for ternary systems Na2SO4–Na2B4O7–H2O and Li2B4O7–Na2B4O7–H2O at 273 K were obtained experimentally by the...     

Synthesis and characterization of octa- and hexanuclear polyoxomolybdate wheels: role of the inorganic template and of the counterion

Eight new compounds based on [O3PCH2PO3]4- ligands and {MoV2O4} dimeric units have been synthesized and structurally characterized. Octanuclear wheels encapsulating various guests have been isolated with different counterions. With NH4+, a single wheel was obtained, as expected, with the planar CO32- guest, (NH4)12[(MoV2O4)4(O3PCH2PO3)4(CO3)2].24H2O (1a), while with the pyramidal SO32- guest, only the syn isomer (NH4)12[(MoV2O4)4(O3PCH2PO3)4(SO3)2].26H2O (2a) was characterized. The corresponding anti isomer was obtained with Na+ as counterions, Na12[(MoV2O4)4(O3PCH2PO3)4(SO3)2]39H2O (2b), and with mixed Na+ and NH4(+) counterions, Na+(NH4)11[(MoV2O4)4(O3PCH2PO3)4(SO3)2].13H2O (2d). With [O3PCH2PO3]4- extra ligands, the octanuclear wheel Li12(NH4)2[(MoV2O4)4(O3PCH2PO3)4(HO3PCH2PO3)2].31H2O (4a) was isolated with Li+ and NH4+ counterions and Li14[(MoV2O4)4(O3PCH2PO3)4(HO3PCH2PO3)2].34H2O (4c) as a pure Li+ salt. A new rectangular anion, formed by connecting two MoV dimers and two MoVI octahedra via methylenediphosphonato ligands with NH4+ as counterions, (NH4)10[(MoV2O4)2(MoVIO3)2(O3PCH2PO3)2(HO3PCH2PO3)2].15H2)O (3a), and Li9(NH4)2Cl[(MoV2O4)2(MoVIO3)2(O3PCH2PO3)2]. 22H2O (3d) as a mixed NH4+ and Li+ salt have also been synthesized. The structural characterization of the compounds, combined with a study of their behavior in solution, investigated by 31P NMR, has allowed a discussion on the influence of the counterions on the structure of the anions and their stability. Density functional theory calculations carried out on both isomers of the [(MoV2O4)4(O3PCH2PO3)4(SO3)2]12- anion (2), either assumed isolated or embedded in a continuum solvent model, suggest that the anti form is favored by approximately 2 kcal mol(-1). Explicit insertion of two solvated counterions in the molecular cavity reverses this energy difference and reduces it to less than 1 kcal mol(-1), therefore accounting for the observed structural versatility.     

Raman spectroscopic study of crystallization from solutions containing MgSO4 and Na2SO4: Raman spectra of double salts

Mg(2+), Na(+), and SO(4)(2-) are common ions in natural systems, and they are usually found in water bodies. Precipitation processes have great importance in environmental studies because they may be part of complex natural cycles; natural formation of atmospheric particulate matter is just one case. In this work, Na(2)Mg(SO(4))(2)·5H(2)O (konyaite), Na(6)Mg(SO(4))(4) (vanthoffite), and Na(12)Mg(7)(SO(4))(13)·15H(2)O (loeweite) were synthesized and their Raman spectra reported. By slow vaporization (at 20 °C and relative humidity of 60-70%), crystallization experiments were performed within small droplets (diameter ≤ 1-2 mm) of solutions containing MgSO(4) and Na(2)SO(4), and crystal formations were studied by Raman spectroscopy. Crystallization of Na(2)Mg(SO(4))(2)·4H(2)O (bloedite) was observed, and the formation of salt mixtures was confirmed by Raman spectra. Bloedite, konyaite, and loeweite, as well as Na(2)SO(4) and MgSO(4)·6H(2)O, were the components found to occur in different proportions. No crystallization of Na(6)Mg(SO(4))(4) (vanthoffite) was observed under the crystallization condition used in this study.