Solubility Of Sulfate Research Articles

Composition of the solution in the hydration of cement

Tests on pure calcium hydroxide solutions have shown that solubility of calcium hydroxide decreases when alkali content increases. With addition of sulfate Ca 2+, concentration of the solution is higher than without it. Higher Ca 2+ concentration is not due to an oversaturation with Ca(OH) 2 but to the higher solubility of calcium sulfate. A similar result also was attained in solutions which are in contact with cement. In those cases Ca 2+ concentration in the solution decreased to the same extent the originally dissolved sulfate was precipitated as ettringite or monosulfate and finally it reached the value corresponding to the Ca(OH) 2 equilibrium. The solutions' pH value rose with increasing alkali content. This effect, however, clearly decreased from potassium to sodium to lithium. If lithium was added to a solution already containing potassium, the pH value decreased although OH-concentration of the solution continued to increase.

Solubility of lead sulfate in water and in sodium sulfate solutions: An experiment in atomic absorption spectrophotometry

Measurement of Pb+2 concentrations by atomic absorption spectrophotometry permits direct calculation of the solubility product constant of lead sulfate in the presence of low concentrations of adde...

Study of Pb(II) in various H 2O-H 2SO 4 mixtures by differential pulse polarography: solubility of lead sulphate, diffusion coefficient of Pb(II) and half-wave potential of Pb(Hg)/Pb(II)

A study of some properties of Pb(II) in solutions of sulphuric acid was carried out by means of differential pulse polarography. The range of concentrations of acid extended from 0.6 to 70 weight % of H 2SO 4 (0.06-11.5 M). Determination of the solubility of lead sulphate was found to be in good agreement with NBS's results in the range of H 2SO 4 concentrations they studied. With increasing concentration in H 2SO 4, the diffusion coefficient was found to decrease more than expected from the Stokes-Einstein equation, while the standard potential of Pb/Pb(II) related to she was found to increase. This led to a more important self-discharge of the negative electrode of the lead-acid battery.

銅陽極不働態化に及ぼす液温の影響

The known effect of increasing electrolyte temperature in preventing anode passivation in copper refining was extensively reviewed.It has been found that a layer of anode slimes formed at a higher electrolyte temperature tends to become more porous with the simultaneous decrease in slime fall. While this increased permeability allows the diffusing ability of Cu2 ions away from the surface of a corroding anode to increase, a gravitational flow of the electrolyte also becomes more pronounced within the slime layer. That is, a more concentrated copper electrolyte at the anode surface streams downwards through the micro pores and cracks, and this type of mass transport removes excessive Cu2+ ions far more efficiently.A thorough investigation of electrolyte properties such as diffusion coefficient of Cu2+ ions, viscosity, solubility of copper sulfate and vapor pressure etc. measured using copper electrolyte of a nominal composition over the temperature range 45-65°C, proves the fact that the gravitational flow is a predominant factor contributing to the decreased tendency to passivate at a higher temperature.That anode passivation occurs more readily at a lower level of anode height is also explainable by this claim.

A thermodynamic model of CaSO 4 solubility in multicomponent aqueous solutions

A thermodynamic model is here developed to describe the solubility of calcium sulphate in salt water. A system of equations based on the ionic atmosphere theory of Debye and Hückel, Born model contribution, and local compositions of the nonrandom two-liquid (NRTL) model is used to describe isothermal activity coefficients for aqueous multicomponent solutions of partially or completely dissociated electrolytes. This approach is an extension of the model of Cruz and Renon for binary electrolyte solutions. Unlike previously published models, where the solubility behaviour of CaSO 4 depends only on the total dissolved solid (TDS) content, our model takes into account the nature and the amount of each ion which is present in the aqueous solution. Using only binary parameters, good agreement is obtained between the experimental and predicted values of calcium sulphate solubility in sea water and in natural and synthetic water (brackish brines), at 25 °C. By letting a limited set of binary parameters to be adjusted in the multicomponent case, we are able to calculate more accurately than previously the solubility behaviour of CaSO 4 over a wider range of salt compositions, including sea-water brines with magnesium augmentation.

Extraction of titanium dioxide into oil from anionic surfactant solutions

Complete extraction of titania (rutile) into various organic liquids from aqueous solutions of sodium tetradecyl, hexadecyl and octadecyl sulphate, at temperatures below the Krafft point, occurs at pH values below the p.z.c. of rutile when the adsorption density at the TiO 2/water interface corresponds to between a vertically orientated monolayer and a bilayer. Under these conditions the receding contact angle is 180° except in the case of sodium octadecyl sulphate where an “armouring” effect produces a significantly lower contact angle. Complete extraction does not occur from aqueous solutions of sodium dodecyl sulphate. There is no obvious relationship between extraction and the oil/water interfacial tension although in general non-polar oils with an interfacial tension against pure water of less than 49.6 mN m −1 extract TiO 2. The adsorption of alkyl sulphate at the TiO 2/water interface is initiated by Coulombic attraction followed by the formation of hydrophobic associations. Extensive adsorption occurs only at concentrations approaching the solubility or cmc of the alkyl sulphates. The adsorption of ion pairs under these conditions is postulated.

Chemical Treatments Associated With North Sea Projects

This paper discusses carbonate and sulfate formation in the Forties field and some of the laboratory inhibitor-selection techniques used to evaluate scale inhibitors for field use in the Forties injection and production systems. Two chemical treatments for stimulation injection wells also are described. Introduction Pressure maintenance in the Forties field began in Dec. 1976. Initial water sampling and core injectivity studies indicated that seawater would be a satisfactory injection fluid.Before commencing injection, the chemical treatment requirements for the seawater injection system were determined. The principal requirement at that time was for an effective microbiological treatment. This was discussed in detail in an earlier publication. Since that time the need has arisen for injection of suitable scale inhibitors into both the injection and production systems to prevent calcium carbonate and barium sulfate scale formation. This paper discusses scale formation in the Forties field and some of the scale-inhibitor selection techniques used. In particular, a novel test method is described that is used to monitor inhibition and flow pattern influence on formation scaling.The water quality aspects of North Sea injection water have been discussed in detail previously. In that study numerous core injectivity measurements were carried out, and the major core plugging mechanism was attributed to the organic portion of seawater. Although no similar plugging has been detected downhole, BP Research has developed a suitable well treatment product to remove organic debris. Some of the results of this study are discussed in relation to potential field application. Field Scale Problems Scale problems occurring in the Forties field can be attributed to two major factors:commingling of Forties formation and injection waters andprecipitation of calcium carbonate scale from formation water due to variations in pressure and temperature in production systems. A partial chemical analysis of Forties formation water and North Sea injection water is given in Table 1. It will be seen that the commingling of formation water and seawater can precipitate both barium and strontium sulfates, which probably are the worst types of scale found in oilfield situations. The solubility of barium sulfate has been calculated as a function of temperature and mixing composition. The results are shown in Fig. 1 and are presented as a stability index, which is the logarithm of the ratio of actual barium sulfate present to the barium solubility under the specified conditions. For example, a stability index of +0.3 indicates the actual barium sulfate present exceeds the solubility limit by a factor of 2 (10 (0.3)).The worst condition exists for relatively large amounts of formation water and small amounts of injection water. JPT P. 904＾

The precipitation of lead sulphate from aqueous and aqueous alcohol solutions: Nucleation, final sizes and morphology

AbstractThe precipitation of lead sulphate was studied from 0.0001 to 0.01 M aqueous solutions (supersaturations 3 to 600) and from 20% aqueous ethanediol, methanol and ethanol solutions, in polypropylene beakers, at ambient temperature: the experimental techniques were conductivity measurements and optical microscopy. The precipitations were heterogeneously nucleated at low supersaturations and homogeneously nucleated at intermediate to high supersaturations. New crystal morphologies generally developed at some what higher supersaturations in the aqueous alcohol systems. The final crystal lengths at first increased with increasing initial metal salt concentration and then decreased with this parameter; the largest crystals at any concentration were obtained from solutions in which lead sulphate solubility was highest. The critical supersaturations (for the onset of homogeneous nucleation) increased from 36 (in water) to 50 (in 20% aqueous ethanol): the surface energies for the formation of nuclei correspondingly increased from 90 to 110 mJ m−2 in good agreement with the Nielsen‐Söhnel relation. The nucleation and crystal growth processes are taking in an aqueous environment of similar water activity to that of the bulk solutions.

Solution properties of sulfated monohydroxy bile salts: Relative insolubility of the disodium salt of glycolithocholate sulfate

Physical-chemical properties of the major sulfated monohydroxy bile salts of man are described. In general, the sulfates are significantly more water-soluble than the non-sulfated species as a result of lower critical micellar temperatures, higher aqueous monomeric solubilities and critical micellar concentrations. Nevertheless, at 37°C the disodium salt of glycolithocholate sulfate, the major monohydroxy bile salt of man is not more soluble than its non-sulfated form. Since aqueous solubility correlates inversely with the cholestatic potential of bile salts, our results suggest that this sulfate may be potentially hepatoxic. Micellar solubility of phosphatidylcholine and cholesterol by the majority of non-sulfated and sulfated monohydroxy bile salts is slight. Nonetheless, phosphatidylcholine is very well solubilized by taurolithocholate sulfate but cholesterol solubility is not increased appreciably. Cholesterol saturation in model bile systems of taurochenodeoxycholate and phosphatidylcholine is impaired by the addition of sulfated lithocholate conjugates but with physiological bile salt compositions this reduction is not significant.

Solubility of aluminum sulfate in aqueous ethanol at 30 and 80.degree.C

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSolubility of aluminum sulfate in aqueous ethanol at 30 and 80.degree.CAlan B. Gancy and Christian A. WamserCite this: J. Chem. Eng. Data 1979, 24, 3, 192–194Publication Date (Print):July 1, 1979Publication History Published online1 May 2002Published inissue 1 July 1979https://doi.org/10.1021/je60082a015RIGHTS & PERMISSIONSArticle Views195Altmetric-Citations1LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (343 KB) Get e-Alerts Get e-Alerts

The application of DPASV to the determination of the low temperature solubility of lead sulphate in sulphuric acid solutions

Measurements of the solubility of lead sulphate in 35% by weight sulphuric acid, pure water, and at two intermediate acid concentrations have been made over the temperature range 25 °C to −50 °C using differential pulse anodic stripping voltammetry.Values of the standard enthalpy of solution, derived from the data and from that of other workers, have been found to be higher than those obtained from emf measurements. The extent of lead sulphate ion pairing is analyzed at 25 °C and discussed. The slowness of equilibration of acid solutions supersaturated with lead sulphate was judged of importance in deciding the relevance of the use of thermodynamically calculated lead ion concentrations with respect to lead acid battery mechanisms.

Effect of S-35 tracer, particle size and imperfection on the solubility of barium sulphate

Solubilities of barium sulphate were enhanced 5–10% with 35S at 5–50 mCi/g-S. These effects of radioisotopic tracer confirm Ramette and Anderson (1963) and Bovington (1965) but are not so large as Spitsyn et al. (1960). They are attributed to structural irregularities arising from nucleation of surface facets by continuous internal irradiation during crystal growth. Kinetic solubilities and saturation solubilities/μmol dm -3 of non-radioactive specimens, were as follows: I (rhombs, 5–15 μm) 10.4, 12.5; II (irreg. stars, <5 μm) 11.0, 10.9; III (agg. colloid, <0.2 μm) 13.5, 13.0; IV (rhombs from anhydrous flux, ~1 mm, crushed) 10.2, -. The sequence of kinetic solubilities IV ≈ I < II < III confirms the enhancemeny of solubility by smaller and less perfect crystal surfaces. The elevated saturation solubility of I is attributed to disintegration of crystal kernels after unravelling of perfected outer layers. With crushed and mounted specimens the effects of irregularities of particle sizes and surface facets were evident.

Solid solution of calcium sulfite hemihydrate and calcium sulfate.

Formation of solid solution of calcium sulfite hemihydrate and calcium sulfate and the solid solubility limit thereof were investigated. In the products prepared by coprecipitation of calcium sulfite hemihydrate and calcium sulfate from aqueous solutions containing sulfate and sulfite ions in different ratios, presence of sulfate which can not be removed by washing with water and is assumed to be incorporated into CaSO3⋅1/2H2O crystal lattice was confirmed. The products were verified to be solid solution of calcium sulfite hemihydrate and calcium sulfate by means of differential thermal analysis, thermogravimetry, IR spectroscopy and X-ray diffraction analysis. Solid solubility of sulfate in CaSO3⋅1/2H2O was indicated to be dependent on reaction temperature, and it was, in the present investigations, about 9mol% at 15°C, increasing with temperature to the maximum value of about 19.5mol% at 83°C and higher. It was found that sulfate ions up to about 9mol% substituted in good order for sulfite ions of CaSO3⋅1/2H2O to form solid solution accompanying small changes in lattice parameters, and that sulfate ions of more than 9mol% caused disorder of sulfite crystal. In addition, from the results of examination of thermal properties and content of combined water of this solid solution, it was considered that the state of forming solid solution changed at the solid solubility of about 9mol%.

HYDRAULIC DESIGN OPTIMIZATION OF ELECTRODIALYSIS FOR DEMINERALIZING BRACKISH WATERS

Abstract Conventional electrodialysis process design is largely empirical, requiring either experimental determination or previous experience with closely similar conditions. Formal cost minimization is not usually considered. This paper presents a non-linear programming model, with a posynomial cost function, subject to a number of hydraulic,-physicalchemical, and other constraints. The cost function includes terms proportioned to membrane area, D.C. power and pumping power. The hydraulic characteristics of electrodialysis spacers arc modelled as a packed-column, or Ergun-type expression, based on the summation of separate laminar and turbulent flow components. The laminar component is a modified Hagen-Poiseuille equation for flow through circular tubes; and the turbulent component is a modified Darcy-Weisbach equation for flow in closed conduits. Constraints arise from considerations of calcium sulfate solubility, limitations on available materials for spacers, and concentration (expressed in terms of l...

Reclamation of irrigation field drainage water

Tests were run for eighteen months on three Reverse Osmosis pilot plants, tubular, spiral wound, and hollow fine fiber. All three modular designs were effective in desalting the agricultural waste water return flow and provided a high quality product. Successful desalination was contingent primarily upon adequate feedwater pretreatment and upon maintenance of the R.O. modules. Conditions imposed by the feedwater were (a) seasonal variations in the level of feedwater total dissolved solids, (b) a high calcium sulfate content and the limitation imposed by the low solubility of the calcium sulfate, (c) the presence of bacterial organisms capable of attacking the membrane material itself or in creating a buildup of material that “fouls” the membrane surface. The productivity of the reverse osmosis process pilot plants was limited by the fouling and scaling characteristics of the agricultural waste water. The use of sodium hexametaphosphate to inhibit calcium sulfate precipitation resulted in increased desalted water production. The further addition of ion exchange pretreatment to remove hardness (Ca +2 and Mg +2 ions) from the agricultural waste water was successfully demonstrated and increasing product water recovery to our stated goal of ninety percent.

Selective separations via recrystallization

Abstract The principles of selective separations by recrystallization are explained and formulae for the calculation of decontamination factors are presented. Experiments with strontium sulfate and radioactive strontium ions demonstrate the validity of the theoretical considerations. Similar or higher decontamination factors are found than those calculated for a uniform distribution of the radioactive strontium ions between crystals and solution. The high values are explained by assuming a recrystallization mechanism which consists of dissolution and redeposition of crystal layers. The half-times of recrystallization increase sharply with Sr2+ or SO 4 2− concentration in the solution. In nitric acid solutions as well as in mixtures containing nitrates and nitric acid the solubility of strontium sulfate is rather high, accordingly the decontamination factors are low under these conditions and furthermore the recrystallization half-times are long.

The solubility of calcium sulfate in aqueous solutions of sodium nitrate between 573 and 623 K

The solubility of calcium sulfate in aqueous solutions of sodium nitrate between 573 and 623 K

Thermodynamics of silver sulfate solubilities in aqueous sulfuric acid and sodium nitrate solutions, 0–60°C

In order to test further the adherence of solubility products of a 1–2 metal sulfate to an extended Debye-Hückel equation, solubilities of Ag 2SO 4 in NaNO 3H 2O and H 2SO 4H 2O solutions were determined from 0 o to 60°C. These data, agreeing with those at 25°C in the literature, were evaluated to obtain solubility products ( Q sp ) at the several ionic strengths by use of second ionization constants of bisulfate ion ( K 2) and an iterative process. Values of Q sp fitted well to an extended Debye-Hückel equation, yielding solubility product constants ( K sp ) at 0·4–60°C. These values agreed with those of Lietzke and Stoughton at 25–200°C when both sets were calculated using the same values of K 2. Thermodynamic functions for the solubility product constant behavior of silver sulfate from 0 to 200°C are presented for comparison with the previously published values.

Solubility and thermodynamic functions for a 3–2 salt, samarium sulfate, in water and sulfuric acid solutions at temperatures to 350°C

To broaden the types of salts studied in high temperature aqueous systems, solubilities of 3-2 samarium sulfate hydrates have been determined in water (25–350°C) and in aqueous sulfuric acid (150–250°C). The values in water for the octahydrate decrease from 0·033 m at 25°C to 8 × 10 −6 m for a lower hydrate at 350°C. Assumptions of several sets of ionic species saturating the sulfuric acid solutions have been tested by extended Debye-Hückel theory, which suggests that the 3-2 samarium sulfate may behave predominantly as a 2-2 sulfate at high temperatures, thus producing Sm 2(SO 4) 2 2+ and SO 4 2− ions in solution. Similar treatment of Lietzke and Stoughton's solubilities of lanthanum sulfate in sulfuric acid at 135–160°C is not inconsistent with this suggestion. Based on behavior as a 2-2 salt, thermodynamic functions for the solubility of samarium sulfate hydrate at 150–250°C are presented, together with some comparisons from the solubilities of lanthanum sulfate hydrate.

The ionization constant of nitric acid at high temperatures from solubilities of calcium sulfate in HNO 3H 2O, 100–350°C; activity coefficients and thermodynamic functions

Solubilities of calcium sulfate have been determined in aqueous nitric acid solutions to high molalities at temperatures from 100 to 350°C. Equations were developed for obtaining ionization quotients ( Q n ) of nitric acid from the solubilities with the use of second ionization constants of sulfuric acid and solubility product constants of calcium sulfate together with their activity coefficients. By Debye-Hückel extrapolations of Q n ionization constants ( K n , molal units) of nitric acid were obtained. These constants agreed with earlier values from raman spectra [Krawetz (1955) at 0, 25, and 50°C] and electrical conductance [Noyes et al. (1907) at 218 and 306°C]. Uncertainties, however, in K n at 350°C may have resulted from reversible decomposition of the acid or hydrolysis of Ca 2+. Values of K n ′ (molar units) decrease from 45 at 0°C to about 0·003 at 350°C, which is 3–5 times lower than ionization constants of 1-1 salts at 350°C. The equation for the variation of K n ′ with temperature of Young et al. (1959) is substantiated, and thermodynamic functions are calculated. Activity coefficients for both CaSO 4 and HNO 3 equilibria are obtainable from the results. These activity coefficients may be used to calculate solubilities of CaSO 4 in other high-temperature mixed electrolyte systems. The dominant species present in the system studied are presented for both low and high temperatures.