Modification of FGD gypsum in hydrothermal mixed salt solution

A novel utilization way of the sludge from wet calcium-based flue gas desulfurization （FGD） processes has been developed in this paper. This study focused on the conversion of the FGD gypsum into α-hemihydrate calcium sulfate by a hydrothermal salt solution method at atmospheric pressure. Experimental study has been carried out in a batch reactor. Qualitative and quantitative analyses were made by DSC/TG thermal analysis, SEM, XRD, metalloscope and chemical analysis. The experimental results showed that the modification of FGD gypsum was controlled by the dissolution and recrystallization mechanisms. With the introduction of FGD gypsum the salt solution was supersaturated, then crystal nucleus of α-hemihydrate calcium sulfate were produced in the solution. With the submicroscopic structure of FGD gypsum crystal changed, the crystal nucleus grew up into α-hemihydrate calcium sulfate crystals. Thus ,the modification of FGD gypsum was fulfilled.

Separation of mixed salts(Cl-/SO42-) by ED based on monovalent anion selective membranes

The industrial products or wastewater rich in the mixed salts(Cl-/SO4^2-) not only causes the environmental damage, but also induces waste of resource. In this study, an ED stack with monovalent selective AEMs and conventional CEMs was employed to separate the Cl-and SO42-from simulated wastewater. The effect of current density and mass fraction percentage was investigated in order to optimize the experimental conditions during ED process. It was found that at a concentration ratio between NaCl and Na2SO4 of 95/5(wt%/wt%) and a current density of40 m A·cm^-2, a current efficiency of 72%, an energy consumption of 1.6 k W·h·kg^-1 Na Cl and a Cl-/SO4^2-concentration(67.5/3.5 g·L^-1) were obtained. Hence, it is appropriate and effective to separate Cl-and SO42-by ED using the monovalent selective AEMs.

Anodising of 2024-T3 aluminium alloy in electrolyte of sulphuric-boric-phosphoric mixed acid containing cerium salt as corrosion inhibitor

The effect of cerium salt as an inhibitor in anodising of the2024-T3aluminium alloy was studied.Scanning electronmicroscopy equipped with energy dispersive X-ray spectroscopy was used to study the surface composition of the alloy before andafter surface preparation.A mixed electrolyte of10%sulphuric acid,5%boric acid and2%phosphoric acid containing0.1mol/Lcerium sulphate salt was used as the anodising electrolyte.Sealing treatment was also done in boiling water and molten stearic acid.Electrochemical impedance spectroscopy and salt spray techniques were performed in order to investigate the corrosion behaviourand durability of the oxide films,respectively.It was concluded that the presence of cerium ions in anodising electrolyte resulted inthe increase in homogeneity,the rate of oxide film growth and also the thickness of the oxide layer,owing to the high oxidisingpower of cerium ion.

Temperature-resistant and salt-tolerant mixed surfactant system for EOR in the Tahe Oilfield

A new temperature-resistant and salt-tolerant mixed surfactant system(referred to as the SS system)for enhancing oil recovery at the Tahe Oilfield(Xinjiang,China)was evaluated.Based on the analysis of the crude oil,the formation water and rock components in the Tahe Oilfield,the long-term thermal stability,salt tolerance and the ability to change the wettability,interfacial activity and oil washing efficiency of the mixed surfactant system were studied.The system contains the anionic surfactant SDB and another cationic surfactant SDY.When the total mass concentration of the SS solution is 0.15 wt%,m(SDB)/m(SDY)ratio is 1 to 1,and excellent efficiencies are achieved for oil washing for five kinds of Tahe Oilfield crude oils(more than 60%).In addition,after adding cationic surfactant,the adsorption capacity of the surfactant is further reduced,reaching 0.261 mg/g.The oil displacement experiments indicate that under a temperature of 150°C and a salinity of 24.6×104 mg/L,the SS system enhances the oil recovery by over 10%after water flooding.The SS anionic–cationic surfactant system is first presented in the open literature that can be successfully applied to obtain predictions of Tahe Oilfield carbonate reservoirs with a high temperature and high salinity.

Decolorization of azo dyes with high salt concentration by salt-tolerant mixed cultures under anaerobic conditions

Because the lack of detailed study of biological decolorization in high salt dye wastewater, it is still difficult to evaluate the biological treatment on high-salinity dye wastewater. The experiments were carried out to study the salt-tolerant bacteria, which is useful in the treatment of high-salinity colored wastewater. Simulated wastewater containing 5-150 g/L salt （NaCI） and 50-2000 mg/L Reactive Brilliant Red K-2BP was treated with three salt-tolerant mixed cultures （CAS, TAS, DSAS）, which were under a gradually acclimated procedure. With the increase of concentrations of salt and dye, the decolorization became low. The abilities of decolorization of dyes wastewater by three mixed cultures （CAS, TAS, DSAS） were studied, CAS and DSAS mixed cultures showed more active for the treatment of high-salinity colored wastewater than TAS mixed cultures. The results suggested that there might be a simple process for the high salt wastewater treatment, which could be incorporated into conventional activated sludge plants.

Salt Desert and Saline-Ackaline Mixed Dust Storms:An Ignored Issure for Global Climate Change

Salt desert,saline-alkaline dust storm and saline-alkaline mixed dust storm are significant but ignored problems for a long time.After many years of observations and researches,the author believes that salt desert,saline-alkaline dust

SYNTHESIS, MAGNETIC PROPERTY AND X-RAY CRYSTAL STUCTURE OF MIXED VALENT COBALT COMPLEX SALT [Co~Ⅲ Cl_2(py)_4][Co~Ⅱ Cl_3(py)]

Complex salt Co_2Cl_5(py)_5 (py=pyridine) was obtained by the reaction of CoCl_2·6H_2O with Bu_4NMnO_4 in pyridine in the presence of benzoic acid. It is monoclinic and crystallizes in space group P2_1/n, fw=690.64, a=28.652(5), b=14.108(4), c=7.424(3) ;β=90.09(1); V=3001(2)~3; Z=4, Dc=1.53g/cm^3. Final R factor is 0.041. The structure consists of a discrete cation [Co~ⅢCl_2(py)_4]^+ and an anion [Co~Ⅱ Cl_3(py)]^-. The Co~Ⅲ ion is coordinated by two Cl^- and four pyridine nitrogen atoms to form an octahedral geometry, and Co~Ⅱ is coordinated by three Cl^- and one pyridine nitrogen atom to form the apices of a tetrahedron. The variable-temperature magnetic susceptility measurement shows no magnet-exchange interaction between Co~Ⅲ and Co~Ⅱ ions.

Nuodeng Salt Village Under the View of Mixed Heritage

Located in Yunlong Dali, Nuodeng salt-village has thousands of years deep in Bai history, culture of the precipitation, the rich historical and cultural heritage of the Bai nationality. In Bai settlement formation and development history, its diverse natural appearances and rich cultural styles have the dual characteristics in natural and cultural heritage. Nuodeng salt-village is a connection between central plains culture and South Asia culture, also a complete ecological museum. By this time, this essay put Jinan springs under the view of mixed heritage based on the background of its history and geography, to identify the natural and cultural value of Nuodeng salt-village by comparison and conclude the heritage protection planning accordingly.

Mixed KPCA结合纹理特征的SVM盐碱土信息提取

核函数是核主成分分析(Kernel Principal Component Analysis,KPCA)的核心,目前使用的核函数都是单一核函数。尝试通过将光谱角径向基核函数(Spectral Angle Radial Basis Function,SA-RBF)与RBF组合形成混合核函数。在研究中,利用基于该混合核函数的KPCA进行特征提取,将其光谱特征波段和纹理特征相结合用于盐碱土的SVM分类,将分类结果与其他SVM分类进行比较,结果表明:该方法优于其他SVM方法,能有效提取玛纳斯河流域绿洲区的盐碱土专题信息,分类精度是89.000%,kappa系数是0.876。

MIXING OF SALT WATER AND FRESH WATER IN THE CHANGJIANG RIVER ESTUARY AND ITS EFFECTS ON SUSPENDED SEDIMENT

Using field hydrological data, the relationship between the mixing of salt water and fresh water and the tidal range/ high tidal level in the Changjiang (Yangtze) River estuary is discussed, and the transporting and concentrating of suspended sediment in the estuary were also analysed in respect to the circulation, flocculation and stratified interface resulting from mixing.The calculation results by two-dimentional box model have confirmed the effects of the circulation on the concentrating of suspended sediment in the estuary. The conclusions derived from this work have deepened the understanding on the mixing in the Changjiang River estuary and are of significance in bo’th theory and practice.

Three Dimensional Baroclinic Numerical Model for Simulating Fresh and Salt Water Mixing in the Yangtze Estuary

For simulating fresh and salt water mixing in estuaries, a three dimensional nonlinear baroclinic numerical model is developed, in which the gradients of horizontal pressure contain die gradient of barotropic pressure arising from the gradient of tidal level and the gradient of baroclinic pressure due to the gradient of salinity. The Eulerian-Lagrangian method is employed to descretize both the momentum equations of tidal motion and the equation of salt water diffusion so as to improve the computational stability and accuracy. The methods to provide the boundary conditions and the initial conditions are proposed, and the criterion for computational stability of the salinity fields is presented. The present model is used for modeling fresh and salt water mixing in the Yangtze Estuary. Computations show that the salinity distribution has the characteristics of partial mixing pattern, and that the present model is suitable for simulation of fresh and salt water mixing in the Yangtze Estuary.

ENTHALPIES OF MIXING FOR PbCl_2-NaCl-BaCl_2 TERNARY MOLTEN SALT MIXTURES

The enthalpies of mixing for the PbCl_2-NaCl-BaCl_2 ternary molten salt mixtures have been measured along four iso-αPbCl_2 Iines by using a SETARAM calorimeter at 873 K.The results show that the molar enthalpy of mixing between iso-αPbCl_2 liquid binary subsystems PbCl_2-NaCl and PbCl_2-BaCl_2 is near zero.approximately fitting the partial ideal solution model.

Effect of Dissolved Cadmium Chloride and Ammonium Chloride Salts on the Enthalpy of Mixing of the Methanol＋Benzene System at 303.15 K

The effect of two dissolved inorganic salts,cadmium chloride CdCl2 and ammonium chloride NH4Cl,on the excess enthalpy of mixing(HE) of the binary system methanol + benzene measured at 303.15 K using an iso-thermal displacement calorimeter with vapor space is investigated in the present work. Compared to the salt-free system,a decreasing trend in the endothermicity of HE values is significant with the addition of CdCl2 salt but the decrease in the HE values is insignificantly smaller with the addition of NH4Cl salt. The experimental values of the enthalpy of mixing are fitted into a Redlich-Kister equation and the deviations in the values and the parameters are reported. The importance of the solute-solvent interactions and the solvent-solvent interactions are demonstrated from the increasing excess enthalpy of mixing values in the positive direction with the increase of salt concentration.

Hot corrosion behavior of Ni–16Cr–xAl based alloys in mixture of Na_2SO_4-NaCl at 600 ℃

The hot corrosion behaviors of Ni–16Cr–xAl（x=4.5%, 6.8%, 9.0%, mass fraction） based alloys in Na2SO4–25% NaCl molten salts at 600 °C were investigated. The effects of pre-oxidation and Al content on the resistance to hot corrosion were examined. The hot corrosion resistance of Ni–16Cr–xAl based alloy with Al addition from 4.5% to 9.0% increases with increasing Al content. The alloy with Al content of 9.0% shows the highest hot corrosion resistance among the examined alloys because more β–NiAl phases are obtained to sustain the Al2O3 scale repaired during hot corrosion. Pre-oxidized specimens have a superior hot corrosion resistance compared with the as-cast specimens, due to a protective oxide scale formed after pre-treatment.

杂质SO_4^(2-)对Solar Salt熔盐热物性的影响及分析

在太阳能光热发电领域,Solar Salt(60%NaNO_3-40%KNO_3,以质量分数计)混合熔盐作为传蓄热介质应用较为广泛。硝酸盐在生产过程中,会夹带部分杂质离子,其中以SO_4^(2-)最为常见。为了研究杂质离子SO_4^(2-)对Solar Salt混合熔盐体系热物性及结构的影响,以质量比为6∶4的NaNO_3/KNO_3的混合熔盐为基础,向其中添加SO_4^(2-),对不同SO_4^(2-)含量的混合硝酸熔盐进行DSC-TG和XRD分析。结果表明,杂质离子SO_4^(2-)对Solar Salt混合熔盐熔点和相变潜热影响较小,上限温度轻微降低,热稳定性变差;XRD结果表明,在混合熔盐冷却时,SO_4^(2-)优先与Na^+结合。

Soil microbial activity and community structure as affected by exposure to chloride and chloride-sulfate salts

Mixed or chloride salty ions dominate in saline soils, and exert wide-ranging adversely affect on soil biological processes and soil functions. The objectives of this study were to（1） explore the impacts of mixed（0, 3, 6, 10, 20 and 40 g Cl–/SO42–salt/kg dry soil） and chloride（0, 1.5, 3, 5, 8 and 15 g Cl– salt/kg dry soil） salts on soil enzyme activities, soil physiological functional（Biolog） profiles and microbial community structure by using soil enzymatic, Biolog-Eco microplates as well as denaturing gradient gel electrophoresis（DEEG） methods, and（2） determine the threshold concentration of soil electronic conductivity（EC1：5） on maintaining the functional and structural diversity of soil microbial community. The addition of either Cl– or mixed Cl–/SO42–salt obviously increased soil EC, but adversely affected soil biological activities including soil invertase activity, soil microbial biomass carbon（MBC） and substrate-induced respiration（SIR）. Cl– salt showed a greater deleterious influence than mixed Cl–/SO42–salt on soil enzymes and MBC, e.g., the higher soil MBC consistently appeared with Cl–/SO42–instead of Cl– treated soil. Meanwhile, we found that SIR was more reliable than soil basal respiration（SBR） on explaining the changes of soil biological activity responsive to salt disturbance. In addition, microbial community structures of the soil bacteria, fungi, and Bacillus were obviously affected by both salt types and soil EC levels, and its diversity increased with increasing of mixed Cl–/SO42–salt rates, and then sharply declined down after it reached critical point. Moreover, the diversity of fungal community was more sensitive to the mixed salt addition than other groups. The response of soil physiological profiles（Biolog） followed a dose-response pattern with Cl–（R2=0.83） or mixed Cl–/SO42–（R2=0.89） salt. The critical threshold concentrations of salts for soil physiological function were 0.45 d S/m for Cl– and 1.26 d S/m for Cl–/SO42–, and those for soil microbial community structural diversity were 0.70 d S/m for Cl– and 1.75 d S/m for Cl–/SO42–.

Research on Properties of Metasilicate Bonded Carbon-free Basic Dry Vibration Mix

Carbon-free basic dry vibration mix was prepared using middle grade magnesia and fused magnesia as main starting materials,metasilicate replacing phenolic resin as binder,adding a certain amount of medium and low temperature intensifiers. Effects of binder,grain composition,and additives on basic dry vibration mix for tundish were studied,and the bonding mechanism was also analyzed. The results show that：（1） when using metasilicate as binder,the higher strength can be acquired; （2） the suitable grain composition is q=0.48,the critical granularity is 5 or 3 mm,the fines addition is 10%-20% （mass percent）; （3） the strength and corrosion resistance of the basic dry vibration mix can be improved by the melting compound of metasilicate and additives; （4） with temperature rising,the bonding type in dry vibration mix changes from cohere bonding to reaction bonding,and then to ceramic bonding at last.

钾混盐粒度组成对其转化浮选的影响机制研究

硫酸钾对中国粮食生产至关重要,为加快硫酸钾的高效制备,保障中国农业的稳定发展,对合成硫酸钾的关键中间产物软钾镁矾的制备进行研究。首先针对罗布泊盐湖钾混盐粒度易随季节变化而差异显著导致软钾镁矾制取效率低的问题,通过磨矿-转化-浮选工艺探究钾混盐粒度组成对其转化浮选的影响机制,结果表明,钾混盐粒度越细,转化程度越高且转化产物粒度也越细。钾混盐磨矿3 min后对应的<0.074 mm转化产物占比达42.69%,且钾离子主要分布于该粒级物料中。同时,钾混盐粒度对软钾镁矾的浮选行为具有显著影响,其浮选效率随钾混盐粒度的减小呈先上升后下降趋势,当钾混盐<0.250 mm粒级占比为79.78%时,软钾镁矾制取效率最高。此外,还进行了转化产物粒度对软钾镁矾和氯化钠浮选分离的影响研究,结果表明,转化产物粒度越细,软钾镁矾和氯化钠浮选速率常数差值越小,在<0.074 mm时仅为0.0945 min-1,此时二者难以有效分离。研究结果对软钾镁矾生产工艺调控和优化具有重要的指导意义。

温度影响下罗布泊盐岩路基填料变形特性研究

为探明温度影响下盐岩路基填料变形特性,保障盐岩路基稳定性,促进盐岩在路基工程中资源化应用,全面分析了卤水及盐岩相变特征,基于正交试验方法探究了单次降温多因素交互作用下盐岩填料的变形规律,系统研究了多次冻融循环后盐岩填料盐胀累积规律,并基于试验段现场监测综合评价了盐湖区盐岩路基变形特征。结果表明:不同浓度卤水降温曲线均未出现明显过冷阶段,其降温曲线平衡及波动维持时间极为短暂,同时卤水相变温度随浓度增加而升高。盐岩填料的降温曲线存在显著的过冷及温度跳跃阶段,其相变温度随拌和卤水浓度增加而下降。单次降温作用下盐岩填料变形量介于-0.09~0.18 mm,各因素对盐岩填料变形的影响顺序为:上覆荷载>含卤水率>最大粒径>压实度。冻融循环作用下拌合卤水浓度越低,盐岩填料盐胀量越大;上覆荷载对盐岩填料盐胀抑制作用较强。实体工程现场监测表明随着监测时间增长盐岩路基变形呈现正弦波式周期性变化,且变形沿深度方向呈减小趋势,同时盐岩路基变形与温度具有较强的线性相关性。

混合盐碱胁迫对花生种子萌发及幼苗生长的影响

【目的】研究混合盐碱胁迫对花生种子萌发及幼苗生长的影响,为盐碱地的有效利用与耐盐品种的培育提供依据。【方法】以花生品种花育25号为材料,人工模拟混合盐碱胁迫条件,测定花生种子发芽率、发芽势、发芽指数、活力指数、盐害率及花生幼苗的根长和茎长。【结果】(1)高浓度胁迫下,Cl^(-)和SO_(4)^(2-)组成的混合盐碱溶液对花生种子萌发产生强抑制效果;当混合盐碱溶液的pH值>10时,对花生种子初生幼苗生长产生强抑制效果;(2)不同浓度的混合盐碱胁迫对发芽率、发芽势、发芽指数、活力指数、盐害率、根长、茎长均产生了不同程度的影响,高浓度的混合盐碱会对花生种子萌发产生抑制作用;(3)花生对各处理的耐盐碱性从大到小依次为B>C>D>E>A。【结论】不同的混合盐碱成分及浓度对花生种子的影响不同,而种子萌发期是植物对盐碱胁迫最敏感的时期。