Hydrochemistry of various stages of Brine in subsoil salt-pan

Manufacture of common salt by evaporation of natural brine has been renowned from past. The southern state of Tamil nadu in India, 75% of the salt is made by solar evaporation of sea brine, 20% from subsoil brine and therefore the rest from backwater. For the manufacture of salt and its by-products by the evaporation of brine, the information of each the composition of the brine and its phase chemistry is important. Underground brine (subsoil) is considered to be the sea water cut-off from oceans and concentrated by sunlight. It contains the elements of chloride, sulphate, calcium, magnesium, sodium and potassium in higher proportion. The physical parameter of rainfall data was collected because it interferes by diluting the brine and reducing the rate of evaporation. The monitoring of the physical and chemical parameters of brine at various stages viz, source, reservoir, condenser, crystallizer and bittern of the subsoil salt-pan gives plentiful possibilities for the management of the salt-pans. The results of chemical parameters and their seasonal dissimilarities were studied for a period of one year. (Jan-Dec 2019).

Dynamic variations in salinity and potassium grade of a potassium-rich brine deposit in Lop Nor basin, China

The Quaternary Lop Nor playa is the largest production base of potassium sulfate in the world. It has a mining history of more than 10 years, and its share in the Chinese potassium sulfate market is about 50% to-date. In this basin, the high-salinity potassium-rich brines are mainly contained in Middle Pleistocene–Holocene glauberite strata. Based on the monitoring of the underground brine table and geochemical analysis, this study reveals variations in the underground brine table and potassium-bearing grade before and after large-scale mining in the Lop Nor potash deposit. The results showed that the underground brine table and potassium sulfate grade decreased by varying degrees over sub-mineral areas after large-scale mining. The underground brine table declined by 8.5 m, on average, in the Luobei depression, by 6.4 m in the Tenglong platform and by 1.9 m in the Xinqing platform. However, the potassium-bearing grade showed the different trend. The Tenglong platform had the largest decline with average decreases in layers W1, W2 and W3 of 18.2%, 13.0% and 24.8%, respectively. In the Xinqing platform, the average decrease in layersW2 and W3 were 17.4% and 16.0% respectively. The Luobei depression decreases were relatively small (W1, W2 and W3 decreased 4.3%, 4.2% and 3.1%, respectively). This research provides a theoretical basis for the rational development and sustainable use of the potassium-rich brines in the Lop Nor basin.

Study on the 4-ethyl-2(α-methyl benzyl) phenol Extraction-Separation Between Rubidium and Potassium

More than 92% of rubidium resources on the earth exist in salt lake brine and underground brine. Rubidium in brine coexists with a large amount of potassium with very similar physical and chemical properties, making the extraction technology of rubidium extremely difficult, and a large amount of rubidium resources in brine have not been rationally utilized. Therefore, the development of a new type of high-selectivity rubidium-potassium separation extractant is of great significance to the establishment of efficient separation and extraction technology of rubidium. By modifying the structure of 4-tert-butyl-2-(α-methylbenzyl)phenol, the traditional rubidium extractant, the steric hindrance effect of tert-butyl is reduced and the reaction efficiency of rubidium and extractant is improved. A new extractant 4-ethyl-2-(α-methylbenzyl)phenol was obtained. The thesis carried out the research on the extraction and separation performance of potassium rubidium 4-ethyl-2-(α-methylbenzyl)phenol. The results show that the new extraction agent 4-ethyl-2-(α-methylbenzyl)phenol and potassium rubidium brine are extracted and separated with a ratio of 10:1. The minimum separation coefficient of rubidium potassium can reach 15 or more, showing excellent separation performance ; When the organic phase is composed of 0.8mol/L extractant and D60 solvent oil, the alkalinity of the aqueous phase is 0.5mol/L sodium hydroxide, and the extraction time is 3 minutes, the single-stage extraction rate of rubidium can reach more than 76.0%, rubidium potassium The separation coefficient can reach more than 26. After repeated use, the extraction rate of rubidium can be maintained above 73% and the separation coefficient of rubidium potassium can reach 23, without a significant drop. It provides a new way and idea for the extraction and separation technology of rubidium in high potassium brine.

SBAS-DlnSAR monitoring of subsidence induced by extracting brine from an underground salt deposit in Tuzla, Bosnia and Herzegovina

Tuzla City, Bosnia and Herzegovina, is very famous for salt mining. The intensive extraction of brine from the underground salt deposit caused accumulative subsidence of up to -12 m from 1956 to 2003. It induced serious damage to residences, buildings, and infrastructures. Although the activity of brine extraction was officially stopped in 2007, reports of subsidence are still on-going for some areas of Tuzla City according to a previous study. In the present study, a satellite-based method, i.e., Differential Synthetic Aperture Radar (DInSAR), is applied for the subsidence monitoring of the induced underground brine extraction. Since October 2014, SAR data obtained by the Sentinel-1A and -1B satellites (European Space Agency: ESA) and Small Baseline Subset (SBAS) multi-temporal analyses have been employed to obtain the spatial distribution and the temporal transition of the land subsidence. The accuracy and effectiveness of the SBAS-DInSAR method are assessed and evaluated by using the real-time kinematic GNSS monitoring system. DInSAR detected that the subsidence is still on-going at a velocity of -36.4 mm/year in some areas, especially in an area northeast of the center of the city. This study presents the validity and effectiveness of SBAS-DInSAR as a useful subsidence monitoring tool.

Modeling method of prediction model for salt field ion concentration under solar thermal system using random forest

At present, the underground brine deposit of Lop Nor salt lake in Xinjiang, while is rich in solar energy resource and can be one high efficient solar thermal utilization area, has become an important potash production base in China. During the development of salt lake brine, the collection methods are different according to the concentration of ions in different locations. In order to solve the problems of low accuracy and high calculation cost in prediction of salt field ion concentration, a data mining method based on random forest is applied in this paper. To build the model, we collected K+, SO42?, Cl?, and other two kinds of ions, among which the features included the collection time, collection locality and the number of salt pond. We used several methods to train and test the sample data, evaluated the experimental results using a variety of performance metrics and compared it with other methods at the same time. The results revealed that the optimal random forest model yielded the mean square error and coefficient of determination values of 0.073 and 0.940, which performed relatively better than support vector machine and extremely randomized trees.

Recovery of Boron from Underground Brine by Continuous Centrifugal Extraction with 2-Ethyl-1,3-hexanediol (EHD) and Its Mechanism

In order to economical and environmental-friendly recycle of boron from underground brine, the extraction of boron was carried out in this work by the continuous centrifugal technique using 2-ethyl-1,3-hexanediol (EHD) + sulfonated kerosene (SK) extraction system, and the extraction mechanism was also investigated by the combination of FT-IR with slope method. The results showed that boron can be effectively extracted from underground water with the concentration of boron 5.43 g·L−1 by five-stage centrifugal extraction using 30% EHD + 70% SK at pH = 2.0–3.0, R(O/A) = 1 : 2, and the extraction rate reached 98.46%. Boron in the organic phase can be well five-stage back-extracted by 1.0 mol·L−1·NaOH at R(O/A) = 1 : 1 with a back-extraction rate of 97.00%. About 88.32% boron in the aqueous phase obtained by back-extraction can be recycled in H3BO3 form by evaporation crystallization after acidified to pH < 2.5. The extraction mechanism indicated that the extraction is completed mainly based on the esterification reaction between alcoholic hydroxyl in EHD and -OH in B(OH)3 at the stoichiometric ratio 1 : 1 to generate a stable six-membered ring structure of boric acid ester.