老卤蒸发—冷却结晶脱镁的研究          下载免费PDF全文

卢光磊  李海民 《盐湖研究》2010,18(2)

采用蒸发—冷却结晶方法,对青海大柴旦盐湖提钾后的老卤进行脱镁试验研究。试验结果表明,一次蒸发温度为125℃时,老卤的镁去除率达到了33%,蒸发冷却后卤水的流动性较好。一次蒸发温度在135℃时,老卤的镁去除率达到了74%以上,但蒸发冷却后的卤水流动性差,过滤性能不佳。二次蒸发采用125℃蒸发后的卤水为原料,没有达到预期效果。  相似文献   

蒙自地区蒸发折算系数分析   总被引：1，自引：0，他引：1       下载免费PDF全文

郑皎  王继红  李华伟 《气象与环境学报》2011,27(1):45-47

利用始于1953年的蒙自气候站小型蒸发器和始于1986年的E-601B型蒸发器蒸发量观测资料,计算两种蒸发器蒸发量的折算系数,并与相关分析及线性拟合的结果进行对比分析。结果表明：蒙自站小型蒸发器与E-601B型蒸发器蒸发量的时程分配基本一致,两者之间具有较好的相关关系,线性拟合的线性系数与折算系数较为一致,且检验结果较为接近,推算出该地区两种仪器年蒸发量的折算系数为0.65。研究结果可用于本地区的气候评价、水量平衡分析、水资源调查等。  相似文献   

蒸发量与土壤湿度和地下通量关系的模式     

陈科信 《地理学报》1988,(2)

土壤水分和蒸发量是水文循环和能量交换过程中一项重要因素.本文根据非饱和土壤水流运动的基本理论,考虑到在地下水位较高的湿润地区,蒸发层中土壤湿度可以得到地下水的补给,作者提出蒸发量与土壤湿度和地下水通量关系的模式.模式中为单一土壤吸力函数,在实际计算中十分简便.  相似文献   

Evaluation of the ventilated chamber for measuring evaporation from a forest     

F. X. Dunin  E. A. N. Greenwood 《水文研究》1986,1(1):47-62

Evaporation from a regenerating forest was determined concurrently by atmospheric measurements of the Bowen ratio, soil water depletion, and by weighing lysimeter. The methods agreed closely over 18 days in spring and 11 days in summer. Accordingly, the Bowen ratio technique was then used as the control against which any effect on evaporation by enclosure of the lysimeter with a chamber of varied ventilation rate could be quantified hourly and daily. Accuracy of gas analysis was checked against lysimeter values. Daily evaporation by the lysimeter was generally unaffected by enclosure—on a few afternoons there was a statistically significant enhancement of hourly values by the chamber. This was accounted for by difference in turbulence between chamber and forest. The general agreement in daytime hourly values is attributed to the frequent occurrence of equilibrium evaporation (rate at which evaporation is independent of ventilation). At night, evaporation was higher during enclosure. Comparisons were not possible with rain or dew. Determination of evaporation by gas analysis agreed within about 5 per cent of lysimeter values during a dry period. We conclude that the ventilated chamber as used provides realistic estimates of evaporation by forests. We show how periods of bias can be anticipated and corrected by theory.  相似文献   

裸地蒸发过程的数值模拟   总被引：4，自引：1，他引：3  

杨邦杰  曾德超  唐登银  谢贤群 《地理学报》1988,(4)

本文以能量平衡为基础,研究了裸地蒸发过程,并提出一个用Fonran语言编写的,在IBM-PC微机上通过的裸地蒸发过程的模拟程序。这一程序能根据地表红外温度或辐射资料计算裸地蒸发量,并分析能量分配过程与土壤中的含水量、温度分布。初步的田间试验说明,计算值与实测值是比较一致的。  相似文献   

The influence of heat conduction on evaporation from sunken pans in hot, dry environment     

I. M. Oroud 《Journal of Hydrology》1998,210(1-4):1-10

Lateral heat conduction across a large circular sunken pan located in a hot, dry environment is evaluated using a numerical procedure. Heat flow across the sunken pan–adjacent soil boundary is calculated using a two-dimensional soil plane. Calculations show that a large temperature differential across the pan–substrate boundary develops during the entire diurnal cycle during January and July, leading to consistently positive heat flow from the soil towards the sunken pan. Heat conduction across the pan–substrate boundary represents 10 and 34% of net radiation over the sunken pan during July and January, respectively. This additional heat source, which is not available for shallow lakes, increases annual evaporation from the sunken pan by about 5–8% in July and January, respectively. In hot arid environments, a sunken pan will overestimate evaporation from a nearby shallow lake/dam due to a larger surface roughness and consistently positive conduction heat flow across the pan–substrate boundary.  相似文献   

大苏干湖湖水蒸发过程中析盐规律及pH值变化          下载免费PDF全文

李兴意  马云麒  彭章旷  杨剑  张棣  马学海  刘玉秀  张艳灵 《盐湖研究》2021,29(4):81-89

卤水蒸发实验多集中在矿化度较高的后期阶段的盐湖,其矿物主要为氯化物及镁的硫酸盐。为了获得碳酸盐—硫酸盐—氯化物整个盐湖演化阶段的析盐及pH值变化规律,使用大苏干湖微咸水(矿化度为26.5 g/L)在28±2 ℃的恒温室内进行蒸发实验。结果表明,在整个蒸发过程矿物结晶析出顺序为单水方解石—石盐—三水碳酸镁—白钠镁矾—泻利盐—六水泻盐—碳酸钠矾,共有七组盐类析出序列,不同于其它硫酸钠亚型的盐湖蒸发沉积规律,大苏干湖微咸水蒸发沉积过程中未见芒硝析出,可能与其特殊的水化学组成有关;pH值由8.82持续降低到6.29。其pH值的变化主要受控于矿物相的析出,在碳酸盐析出过程中pH由8.79迅速降低到7.38,而后以白钠镁矾为主的硫酸盐析出阶段pH降低到6.65,之后在石盐析出阶段pH缓慢降低到6.29。通过微咸水湖的蒸发实验,对于盐湖演化过程中的结晶析盐规律及各析盐阶段的pH值变化规律有了更加全面的认识。  相似文献   

基于超微型贯入试验的黏性土干燥过程中结构强度演化规律研究     

王德银  唐朝生  李建  施斌 《工程地质学报》2014,22(5):818-823

研究土体结构强度对了解土体开裂破坏过程和预防相关工程地质问题有重要意义。以南京地区下蜀土为对象,采用超微型贯入试验方法,分析了试样在干燥过程中的结构强度演化特征。结果表明:所采用的超微型贯入试验方法为定量研究土体在干燥过程中结构强度的演化规律提供了可行的途径,该方法具有操作简单、精度高和含水率适应范围大等优点; 在干燥过程中,当试样处于高含水率阶段时(w24.27%),剖面上的结构强度基本保持一致,空间差异性较小; 在低含水率阶段(w24.27%),试样结构强度空间差异性显著增强,随深度的增加,结构强度呈递减趋势并逐渐趋于稳定; 总体上,土体的结构强度在干燥过程中随平均含水率的减小呈指数递增趋势,这主要是由于土体水分蒸发导致吸力增加,土颗粒之间的作用力增强。此外,由于土体发生收缩变形,土体孔隙比减小,土颗粒间联接点增加,也会对结构强度产生贡献。  相似文献   

Recharge to the inter-dune lakes and Holocene climatic changes in the Badain Jaran Desert, western China   总被引：8，自引：0，他引：8  

Xiaoping Yang  Bingqi Zhu  Bing Xu  Zhibang Ma  Jiaqi Liu 《Quaternary Research》2010,73(1):10-116

We present new estimates on evaporation and groundwater recharge in the Badain Jaran Desert, western Inner Mongolia of northwestern China, based on a modified Penman Equation suitable for lakes in China. Geochemical data and water balance calculations suggest that local rainfall makes a significant contribution to groundwater recharge and that past lake-level variations in this desert environment should reflect palaeoclimatic changes. The chronology of lake-level change, established by radiocarbon and U-series disequilibrium dating methods, indicates high lake levels and a wetter climate beginning at ca. 10 ka and lasting until the late mid-Holocene in the Badain Jaran Desert. The greatest extension of lakes in the inter-dune depressions indicates that the water availability was greatest during the mid-Holocene. Relicts of Neolithic tools and pottery of Qijia Culture (2400-1900 BC) suggest relatively intensive human activity in the Badain Jaran Desert during the early and middle Holocene, supporting our interpretation of a less harsh environment. Wetter climates during the Holocene were likely triggered by an intensified East Asian summer monsoon associated with strong insolation.  相似文献   

尕斯库勒盐湖卤水模拟自然蒸发试验研究   总被引：4，自引：3，他引：1       下载免费PDF全文

王丽娜  许建新  闵秀云  王亚静 《盐湖研究》2011,19(3):26-30

尕斯库勒湖是柴达木盆地众盐湖中较为典型的硫酸镁亚型盐湖。利用相图规律对该盐湖卤水自然蒸发的结晶路线进行了分析,并通过室内模拟自然蒸发试验进行了验证,最终获得了在自然条件下蒸发卤水分步结晶不同盐类的工艺路线,可为该盐湖资源综合利用提供依据。  相似文献