Influences of Soluble Salts on Adsorption Properties of Polycarboxylate Superplasticizers

Polycarboxylate（PC） superplasticizers with different chemical structures were synthesized through free radical co-polymerization reaction.A total organic carbon analyzer was used to investigate adsorption behaviors of PCs,and to evaluate influences of soluble salts on absorption properties of PCs.It is found that adsorption ratios of PCs on cement particles decrease greatly with the addition of Na2SO4;the adsorption ratio of ethers PC with Hydroxyethyl methacrylate（HEMA） group first increases then decreases with the addition of NaCl;the adsorption ratio of esters PC with short side chains first decreases then increases,while the adsorption ratio of ethers PC with HEMA group decreases with the addition of CaCl2;the adsorption ratio of esters PC with short side chains decreases with the addition of Ca（NO3）2;AlCl3 causes the decrease of the adsorption ratio of ethers PC with HEMA group.

Experimental study on grain size and soluble salt of saline soil in western Jilin Province, China

Western Jilin Province is a typical seasonal frost region, and is also one of the severest salinization areas of China. In this study, we aim to examine the saline soil in Da＇an and Wukesong areas, western Jilin Province, and mainly analyze the granulometric composition and distribution of salt in soil profiles. Four sampling sites, two in Da＇an and two in Wukesong respectively, are chosen for study. The granulometric composition, especially silt and clay content change in different sites and soil depths are analyzed. Analysis of total and components of soluble salt shows that the surface soil is weak carbonate saline, in which the main cation is Na＋ and the main anion is HCO3-. The total amount of soluble salt presents a decreasing tendency with increasing depth. The comprehensive analysis ofgranulometric composition and soluble salt shows that the clay content and soluble salt content present similar variation tendency with an increase of depth.

Contribution of underlying terrain to sand dunes: evidence from the Qaidam Basin, Northwest China

Underlying terrain strongly influences dune formation.However,the impacts of underlying terrain on the dune formation are poorly studied.In the present research,we focused on dunes that formed in the alluvial fans and dry salt flats in the Qaidam Basin,Northwest China.We quantified the dunes'sediment characteristics on different types of underlying terrain and the terrain's effects on the surface quartz grains by analyzing grain-size distribution,soluble salt contents and grain surface micro-textures.Results showed that barchan dunes were dominated by medium sands with a unimodal frequency distribution,whose peak corresponded to the saltation load.Linear dunes were mainly composed of fine sands with a bimodal frequency distribution,whose main peak represented the saltation load,and whose secondary peak represented the modified saltation or suspension load.Sand was transported from source area by running water(inland rivers)over short distances and by wind over relatively longer distances.Thus,quartz grains had poor roundness and were dominated by sub-angular and angular shapes.Surface micro-textures indicated that dune sands were successively transported by exogenic agents(glaciation,fluviation and wind).Soluble salt contents were low in dunes that developed in the alluvial fans,which represented a low-energy chemical environment,so the grain surface micro-textures mainly resulted from mechanical erosion,with weak micro-textures formed by SiO2 solution and precipitation.However,soluble salt contents were much higher in dunes that developed in the dry salt flats,which indicated a high-energy chemical environment.Therefore,in addition to micro-structures caused by mechanical erosion,micro-textures formed by SiO2 solution and precipitation also well developed.Our results improve understanding of the sediment characteristics of dune sands and the effects of underlying terrain on dune development in the Qaidam Basin,China.

Effects of Irrigation with Well Water on Chemical Characteristics of a Weakly Alkaline Soil Used as Rice Field

This paper discussed the effects of irrigation with well water on the salinity and pH of a weakly alkaline paddy soil in Fujin of Heilongjiang Province in the north-eastern part of China.It has been found that after seven years the accumulation of total soluble salts did not occur and that the pH of 0～15 cm layer fell down from 7.92～8.30 to 6.76～7.45,and that the content of anion HCO - 3 and its proportion in the total soluble anions have fallen down.Conversion from paddy soil to upland restored the pH of soil,exchangeable sodium,ESR(exchangeable sodium ratio) to their original levels of upland fields respectively.

Extraction and Reaction Mechanism of Potassium from Associated Phosphorus and Potassium Ore

Potassium and phosphate were extracted at low temperature by acid hydrolysis process to decompose a new type of associated phosphorus and potassium ore. The main factors affecting the dissolution rate were investigated, such as grinding fineness, the amount of sulfuric acid and fluoride salt, reaction time and temperature, etc. Meanwhile, the effects of various factors on the formation of soluble potassium and phosphate were also discussed. The reaction products and residues were determined by X-ray diffraction（XRD）, scanning electron microscopic（SEM） analysis and other means. The results showed that the dissolution rates of potassium and phosphorus were 70wt% and 93.7wt%, respectively, under the conditions of a grain size of 95.64wt% lessthan 0.074 mm, 9.78 g·g^（-1） sulfuric acid, 0.5 g·g^（-1） ammonium fluoride, 160 ℃ and a reaction time of 2h. The thermodynamic and chemical reaction mechanism was revealed that the primary reaction could be completed spontaneously in a temperature range of 298-433 K. The increase of reaction temperature had an important influence on ion exchange reaction, which was more conducive to the spontaneous process. The research will open up a new way for efficient use of potassium ore resources.

Research on the distribution of saline soil along the Chaerhan-Golmud Highway, northwestern China

In order to assess and improve the engineering stability of saline soil with high chloride content along a 40-km section of the Chaerhan-Golmud Highway in northwestern China, more than 200 monitoring points for saline soil soluble salt chemical tests were established. The total salt content distribution, the chloride ion content distribution, and the sulfate ion content distri- bution along both sides of road were determined, and the chlorine-sulfur ratio distribution and the PH value distribution along both sides of road were also determined. These chemical contents can significantly affect soil freezing temperatures, frost heave, and salt expansion, which can undermine subgrade stability, ultimately, cause subgrade damage. Therefore, when subgrade filler is selected for this highway, attention must be paid to its chemical indicators as well as its physical properties.

THE SOLUBILITY OF FERROALLOYED NEODYMIUM IN MOLTEN SALT CONTAINING NEODYMIUM TRICHLORIDE

The solubility of ferroalloyed neodymium in molten salt containing neodymium trichloride and the de- pendence of solubility on temperature and composition of the melt are determined by means of electrochemical method.The data obtained are in good agreement with result of chemical analysis of the quenched molten salt samples.

Predictive phase equilibria for the aqueous ternary system(Li_2SO_4 + K_2SO_4 + H_2O) from 273.15 to 373.15 K

1 Introduction Many variable temperature chemical models were developed to predict mineral solubility in the natural waters(Na+,K+,Ca2+,Mg2+//Cl-,SO42-–H2O)in the temperature range below 298.15 K(to near 213.15 K)and(Na+,K+,

Water uptake of multicomponent organic mixtures and their influence on hygroscopicity of inorganic salts

The hygroscopic behaviors of atmospherically relevant multicomponent water soluble organic compounds（WSOCs） and their effects on ammonium sulfate（AS） and sodium chloride were investigated using a hygroscopicity tandem differential mobility analyzer（HTDMA） in the relative humidity（RH） range of 5%–90%. The measured hygroscopic growth was compared with predictions from the Extended-Aerosol Inorganics Model（E-AIM） and Zdanovskii–Stokes–Robinson（ZSR） method. The equal mass multicomponent WSOCs mixture containing levoglucosan, succinic acid, phthalic acid and humic acid showed gradual water uptake without obvious phase change over the whole RH range. It was found that the organic content played an important role in the water uptake of mixed particles.When organic content was dominant in the mixture（75%）, the measured hygroscopic growth was higher than predictions from the E-AIM or ZSR relation, especially under high RH conditions. For mass fractions of organics not larger than 50%, the hygroscopic growth of mixtures was in good agreement with model predictions. The influence of interactions between inorganic and organic components on the hygroscopicity of mixed particles was related to the salt type and organic content. These results could contribute to understanding of the hygroscopic behaviors of multicomponent aerosol particles.

Electric Field Distribution of Soluble Salt Deposition on the Surface of Insulators in Railway Overhead Lines

Different constituents of soluble salts have different effects on the insulation performance of insulators.To study the electric field distribution of soluble salt deposition on the surface of high-speed railway insulators,a two-dimensional model of the cantilever insulator electrostatic field and constant-current field with soluble salt deposition is constructed.The simulation results indicate that the relative dielectric constant of dry pollution is the main factor that affects the electric field distribution on the surface of the insulator.The electric field intensity is arranged in the following order:CaSO_(4)>KNO_(3)>NaNO_(3)>K_(2)SO_(4)>NaCl>MgSO_(4),and the conductivity of each dirty liquid in the wet state becomes a key factor affecting the electric field distribution,which is specifically shown as sodium chloride>nitrate>sulfate.The simulation results are compared with existing test results to verify that they were correct.It is also found that the electric field intensity of the insulator with good hydrophobicity is slightly greater than that of the insulator without hydrophobicity.The results provide a theoretical basis for the classification of regional pollution levels and the testing of insulator contamination in the laboratory.

Study on phase diagrams and properties of solutions in ternary systems Li+,K+(Mg2+)/SO42--H2O at 25℃

Solubilities of ternary systems Li+,K+/SO42--H2O (1) and Li+,Mg2+/SO42-H2O (2) were investigated by isothermal method at 25℃. Physico-chemical properties of solutions, such as density, refractive index, viscosity, conductivity and pH, were determined. Phase diagram of the system (1) consists of three solubility branches and three crystallization fields corresponding to K2SO4, Li2SO4.H2O and LiKSO4. LiKSO4 is an incongruent compound, and its transition point is estimated graphically to be 45.5-46.0℃. No solid solution of LiKSO4 with Li2SO4.H2O was found in the system. The system (2) is a simple eutonic type. Pitzer model of electrolyte solution was used to check the obtained solubilities. Data comparison gives good agreement. Two equations were used to correlate density, refractive index of the solution with its composition. Differences between measured and calculated values are less than 0.6% for density, 0.15% for the latter.

Remediation of saline–sodic soil with flue gas desulfurization gypsum in a reclaimed tidal flat of southeast China

Salinization and sodicity are obstacles for vegetation reconstruction of coastal tidal flat soils. A study was conducted with flue gas desulfurization（FGD）-gypsum applied at rates of 0, 15, 30, 45 and 60 Mg/ha to remediate tidal flat soils of the Yangtze River estuary.Exchangeable sodium percentage（ESP）, exchangeable sodium（ExNa）, p H, soluble salt concentration, and composition of soluble salts were measured in 10 cm increments from the surface to 30 cm depth after 6 and 18 months. The results indicated that the effect of FGD-gypsum is greatest in the 0–10 cm mixing soil layer and 60 Mg/ha was the optimal rate that can reduce the ESP to below 6% and decrease soil p H to neutral（7.0）. The improvement effect was reached after 6 months, and remained after 18 months. The composition of soluble salts was transformed from sodic salt ions mainly containing Na~＋, HCO_3^-＋ CO_3^（2-）and Cl-to neutral salt ions mainly containing Ca^（2＋）and SO_4^（2-）. Non-halophyte plants were survived at 90%. The study demonstrates that the use of FGD-gypsum for remediating tidal flat soils is promising.