在恒离子强度下KCl+KNO_3水溶液中KCl的活度系数及KNO_2~0的缔合常数测定     

陈国华  林洪瑛  姜子东  王立红 《中国海洋大学学报(自然科学版)》1990,(2)

作者用无液界电池电动势法测定了25℃恒离子强度(I=0.1,0.3,0.5和0.7)条件下KCl+KNO_3水溶液中KCl的平均质量摩尔浓度标度的活度系数,发现其活度系数的对数与混合溶液中KNO_3的浓度服从下列公式的关系: Lgγ1±=Lgγ_(1±)~0-a_(12)m_2-β12m_2~2且用最小二乘法求得了各离子强度条件下相应的哈奈特系数。还用Pitzer公式计算了混合溶液中KCl的平均活度系数及超额自由能,计算的活度系数与实验值之间的标准偏差为±0.006。较高的超额自由能表明该体系有较大的混合效应,同时表明在低浓度下K~+-NO_3离子对也可能发生较强的相互作用。已用简单的循环逼近法求算了KNO_3~0的化学计量缔合常数,其结果可用下列经验公式表示: LnK~*=a+bI_e已求得在海水离子强度(I_c=0.68)下KNO_3~0之K~*=2.4,用外推法求得25℃时KNO_3~0的热力学缔合常数值K_a=0.40。  相似文献   

敦煌莫高窟北区岩体变异变形及修复对策     

何德伟  马东涛  吴杨 《工程地质学报》2008,16(2):283-288

敦煌莫高窟北区岩体长期以来在特殊的地形地貌、气象水文、岩土性质、地质构造条件下,受人工开挖、重力、风蚀、雨蚀和洪水冲刷等共同作用,岩体发生风化、卸荷等变异以及崩塌、坍塌和危岩、开裂与裂隙(构造裂隙、卸荷裂隙)等多种变形,严重影响岩体的稳定和洞窟的安全。针对上述变异、变形破坏情况,采用PS材料加粉煤灰浆液灌浆封闭裂隙和岩面喷浆加固相结合的修复方法,有效地防止了岩体变异的进一步扩展和表面风化的加剧,减少了岩体变形和表面风化程度,使石窟得以保护和修复。该方法对黄土及干旱地区石窟保护具有良好的借鉴作用。  相似文献   

食品级氯化钾制备工艺和杂质检测方法的研究进展     

张慧芳  王世栋  郭敏  李权  吴志坚 《盐湖研究》2018,26(3):76-81

食品级氯化钾的制备工艺主要为热溶结晶法,其间通过加入晶种、酸、碱、助滤剂等去除原料中的镁离子、钙离子、硫酸根、有机物等杂质。氯化钾中杂质的检测方法可采用滴定法、电感耦合等离子体光谱法、原子吸收分光光度法、紫外可见分光光度法等。随着食品级氯化钾市场规模的逐渐扩大,行业对产品质量要求也不断提高,其制备工艺技术和杂质检测方法也需不断改进和完善,进一步促进行业有序发展。  相似文献   

Semi‐Micro Reflux Procedure for Minimization of Chloride Interference by COD Determination     

Ayrton F. Martins  Lucas E. W. de Jesus  Nádia Vendruscolo  Tibiriçá G. Vasconcelos  Marcelo L. Wilde 《洁净——土壤、空气、水》2008,36(1):66-69

In this study, a semi‐micro procedure for the COD (Chemical Oxygen Demand) was undertaken to allow the measurement of effluent samples with a high chloride content. It was found that the COD values for standard and effluent samples, corresponded closely to those obtained using the standard method of Burns and Marshall. When the method was applied to samples of industrial wastewater, with a very high chloride content, the recommended procedure proved to be accurate and precise, with RSDs of 6% and 4.3% for the standard and effluent solutions, respectively. The required amount of hazardous reagents was similar to that found in the standard closed reflux method. It was also possible to determine the total amount of oxidized halides. The use of this low‐cost, laboratory‐made system made it unnecessary to acquire an expensive, imported analytical system, while maintaining a high level of accuracy in the determinations.  相似文献   

Characteristics of Milankovitch Cycles in the Mid‐Permian Liangshan and Qixia Formations of the Sichuan Basin—Examples from Well‐Long17 and Well‐Wujia1     

ZHANG Yunbo  JIA Chengzao  ZHAO Zongju  JIANG Zaixing  XU Jie 《《地质学报》英文版》2012,86(5):1045-1059

The Liangshan and Qixia formations in the Sichuan Basin of central China were formed in the earlier middle Permian. Based on outcrop observation of the Changjianggou section at Shangsi, Guangyuan region and 3rd-order sequence division in typical drillings, one-dimensional spectrum analysis has been used to choose the better curve between the natural gamma ray spectrometry log(ln(Th/K)) in Well-Long17 and the gamma ray log(GR) in Well-Wujia1, respectively, for identifying Milankovitch cycles in Sequence PSQ1 which comprises the Liangshan and Qixia formations, and then to identify the variation in the Milankovitch cycle sequences. On this basis, the system tract and 4th-order sequence interfaces in Sequence PSQ1 were found via two-dimensional spectral analysis and digital filtering. Finally, a high-frequency sequence division program was established. Among these cycles, long eccentricity (413.0 ka) and short eccentricity (123.0 ka) are the most unambiguous, and they are separately the major control factors in forming 4th-order (parasequence sets) and 5th-order (parasequences) sequences, with the average thicknesses corresponding to the main cycles being 11.47 m and 3.32 m in Well-Long17, and 14.21 m and 3.79 m in Well-Wujia1, respectively. In other words, the deposition rate in the beach subfacies is faster than that of the inner ramp facies. The ln(Th/K) curve is more sensitive than the GR as the index of relatively ancient water depth in carbonate deposition. One-dimensional spectrum analysis of ln(Th/K) curve could distinguish the Milankovitch cycle sequences that arose from the Precession cycle (20.90 ka), with a much higher credibility. Sequence PSQ1 in Well-Long17 contains 10 4th-order sequences, and the growth span of Sequence PSQ1 consisting of the Liangshan and Qixia formations is about 4.13 Ma. The single deposition thickness of the long eccentricity cycle sequence has the characteristics of thinning and then thickening in the two-dimensional spectrum, which could be used to identify the system tract interface of the 3rd-order sequence. The precession sequence thickness remains stationary. As a result, the early deposition rate in the mid-Permian of the Sichuan basin was very slow, remaining nearly stationary, and this reflects a sustained depositional environment. Whole-rock carbon and oxygen isotope curves could also prove this point. Milankovitch cycle sequence studies provide a basis for paleoenvironmental analysis and, as such, can be used to analyze ancient climate change, calculate deposition rate and deposition time, and carry out fine isochronous stratigraphic correlation.  相似文献   

三元体系K2B4O7-KBr-H2O在323K的相平衡研究          下载免费PDF全文

赵向阳  桑世华  孙明亮 《盐湖研究》2011,19(1):35-39

采用等温溶解平衡法研究了三元体系K2B4O7-KBr-H2O在323 K的相平衡关系及密度。研究发现,该三元体系为简单共饱和型,无复盐及固溶体形成。根据溶解度数据绘制了相图,相图中有一个共饱点,两条单变曲线,单变量曲线所对应的平衡固相分别为K2B4O7.4H2O和KBr;实验结果表明KBr对K2B4O7有较强的盐析作用。并简要讨论了密度变化规律。  相似文献   

Alkali and halogen chemistry in volcanic gases on Io     

Laura Schaefer 《Icarus》2005,173(2):454-468

We use chemical equilibrium calculations to model the speciation of alkalis and halogens in volcanic gases emitted on Io. The calculations cover wide temperature (500-2000 K) and pressure (10⁻⁶ to 10⁺¹ bars) ranges, which overlap the nominal conditions at Pele (T=1760 K, P=0.01 bars). About 230 compounds of 11 elements (O, S, Li, Na, K, Rb, Cs, F, Cl, Br, I) are considered. The elemental abundances for O, S, Na, K, and Cl are based upon observations. CI chondritic elemental abundances relative to sulfur are used for the other alkalis and halogens (as yet unobserved on Io). We predict the major alkali species in Pele-like volcanic gases and the percentage distribution of each alkali are LiCl (73%), LiF (27%); NaCl (81%), Na (16%), NaF (3%); KCl (91%), K (5%), KF (4%); RbCl (93%), Rb (4%), RbF (3%); CsCl (92%), CsF (6%), Cs (2%). Likewise the major halogen species and the percentage distribution of each halogen are NaF (88%), KF (10%), LiF (2%); NaCl (89%), KCl (11%); NaBr (89%), KBr (10%), Br (1%); NaI (61%), I (30%), KI (9%). We predict the major halogen condensates and their condensation temperatures at P=0.01 bar are NaF (1115 K), LiF (970 K); NaCl (1050 K), KCl (950 K); KBr (750 K), RbBr (730 K), CsBr (645 K); and solid I₂ (200 K). We also model disequilibrium chemistry of the alkalis and halogens in the volcanic plume. Based on this work and our prior modeling for Na, K, and Cl in a volcanic plume, we predict the major loss processes for the alkali halide gases are photolysis and/or condensation onto grains. Their estimated photochemical lifetimes range from a few minutes for alkali iodides to a few hours for alkali fluorides. Condensation is apparently the only loss process for elemental iodine. On the basis of elemental abundances and photochemical lifetimes, we recommend searching for gaseous KCl, NaF, LiF, LiCl, RbF, RbCl, CsF, and CsCl around volcanic vents during eruptions. Based on abundance considerations and observations of brown dwarfs we also recommend a search of Io's extended atmosphere and the Io plasma torus for neutral and ionized Li, Cs, Rb, and F.  相似文献   

肥城钾长石矿床地质特征          下载免费PDF全文

刘建生  李宗成  韩代成 《山东国土资源》2004,20(4):50-53

肥城钾长石矿属钾长伟晶岩型脉状矿床，由元古宙末期壳源岩浆侵入活动晚期冷却时形成的硅酸盐残余熔融体沿构造裂隙侵入形成。矿脉具有成群分布的特点，较大矿体具有伟晶岩矿床特有的环带状构造。该区钾长石矿资源潜力较大。矿体裸露地表，适宜露天开采。矿体内部的块体状矿石质量好、易分选，是玻璃、陶瓷等工业领域较理想的生产原料。  相似文献   

北美板块海相钾盐沉积特征、控制因素及其对中国找钾启示          下载免费PDF全文

丁婷  刘延亭  刘成林 《盐湖研究》2022,30(3):122-130

北美钾盐探明资源量占全球已探明资源量的一半以上。本文介绍了北美板块的形成和北美每个成钾盆地成钾环境和盆地演化。从钾盐沉积的条件出发重点论述了钾盐沉积的板块漂移位置的关系,指出北美每个时期的钾盐沉积都与北美板块所处的位置相关;大型和超大型钾盐矿床的形成时期,北美板块都处在中低纬度地区,且因板块的位置而形成了钾盐沉积所需的气候条件。中国的海相盆地在一些时期也具有与北美相似的大地构造环境,如三叠纪的华南陆块、石炭纪的塔里木陆块,因此深刻了解北美大型海相钾盐矿床的成矿规律,对于寻找中国古代海相钾盐矿床有一定的启示意义。  相似文献   

五硼酸钾溶液中含硼物种分布研究          下载免费PDF全文

贾力凡  朱发岩  周永全  刘红艳  王云霞  王广国  景转芳  宋露露 《盐湖研究》2022,30(4)

采用物种分布图和核磁共振实验研究了五硼酸钾溶液中含硼物种的类型、含量和溶液浓度间关系。研究表明五硼酸钾在稀溶液中几乎全部水解为B(OH)3和B(OH)4-;在较浓溶液中主要物种为B3O3(OH)4-和B(OH)3,而B5O6(OH)4-和[B4O5(OH)42-]的含量较小。核磁共振实验研究给出了B(OH)4-, B3O3(OH)4-和B5O6(OH)4-的生成常数K1, K3, K5,研究得出B5O6(OH)4-含量很少的原因是其解聚为其它类型硼酸根离子。外加离子促进五硼酸根离子的生成,而高温条件促进B5O6(OH)4-发生解聚反应。  相似文献