Solubility of gypsum in sea water and sea water concentrates at temperatures from ambient to 65.degree.

Shaffer, Lloyd H.

doi:10.1021/je60033a006

Cited by 14 publications

(4 citation statements)

References 4 publications

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“…The gypsum solubility product in sea water is in the order of 1·52 × 10 −3 mol 2 l −1 (assuming a sea water density of 1030 kg m −3 ) (Shaffer, 1967) and 4·88 × 10 −4 mol 2 l −1 (Kopittke et al. , 2004).…”

Section: Discussionmentioning

confidence: 99%

Diagenetic formation of gypsum and dolomite in a cold-water coral mound in the Porcupine Seabight, off Ireland

Pirlet¹,

Wehrmann

Brunner

et al. 2009

Sedimentology

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Authigenic gypsum was found in a gravity core, retrieved from the top of Mound Perseverance, a giant cold-water coral mound in the Porcupine Basin, off Ireland. The occurrence of gypsum in such an environment is intriguing, because gypsum, a classic evaporitic mineral, is undersaturated with respect to sea water. Sedimentological, petrographic and isotopic evidence point to diagenetic formation of the gypsum, tied to oxidation of sedimentary sulphide minerals (i.e. pyrite). This oxidation is attributed to a phase of increased bottom currents which caused erosion and enhanced inflow of oxidizing fluids into the mound sediments. The oxidation of pyrite produced acidity, causing carbonate dissolution and subsequently leading to pore-water oversaturation with respect to gypsum and dolomite. Calculations based on the isotopic compositions of gypsum and pyrite reveal that between 21·6% and 28·6% of the sulphate incorporated into the gypsum derived from pyrite oxidation. The dissolution of carbonate increased the porosity in the affected sediment layer but promoted lithification of the sediments at the sediment-water interface. Thus, authigenic gypsum can serve as a signature for diagenetic oxidation events in carbonate-rich sediments. These observations demonstrate that fluid flow, steered by environmental factors, has an important effect on the diagenesis of coral mounds

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Section: Discussionmentioning

confidence: 99%

Diagenetic formation of gypsum and dolomite in a cold-water coral mound in the Porcupine Seabight, off Ireland

Pirlet¹,

Wehrmann

Brunner

et al. 2009

Sedimentology

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“…In the range of ambient temperature of the Salton Sea, the solubility of gypsum varies little with temperature so this probably is not an important factor in determining gypsum precipitation (Schaffer 1967;Ostroff and Metler 1966).…”

Section: Temperature Effectsmentioning

confidence: 99%

Sulfide irruptions and gypsum blooms in the Salton Sea as detected by satellite imagery, 1979–2006

Tiffany

Ustin

Hurlbert

2007

Lake and Reservoir Management

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Bright pale-green surface waters, locally called "green tides," are visible to the naked eye and satellite sensors in patches at the Salton Sea, usually between May and November. These were studied using satellite remote sensing and by direct sampling. Algal blooms are ruled out as a cause as phytoplankton abundance, and chlorophyll concentrations were lower within the patches than in surrounding areas. The presence of abundant microscopic gypsum (CaSO 4 ·2H 2 O) crystals in surface waters suggests that scattering from this precipitating salt produces the intense signals. Biogeochemical factors include: the decomposition of organic matter, resultant anoxia and production of hydrogen sulfide by sulfate-reducing bacteria at depth, and oxidation back to sulfate and precipitation of gypsum during wind-induced overturn events. Sulfide concentrations following one such event in September 2005 ranged from 0.3 to 2.7 mg l -1 at the surface and 1.2 to 25 mg l -1 in bottom waters. Gypsum crystals occurred at densities up to 40,000 ml -1 in surface water on that date, most 20-30 µm in length with some as long as 190 µm. From 1998 to 2006, gypsum blooms appear to have increased in intensity and duration implying an increase in sulfide irruptions and anoxia in surface waters. As much as 97 percent of the lake was affected in early summer of 2003 and 75-80 percent in summers of 2005 and 2006. Events lasted for months at a time during these years. This intensification is likely due to the decline in abundance of a planktivorous fish, a hybrid tilapia, the California Mozambique mouthbrooder, leading to increased algal productivity, more severe anoxia and higher levels of dissolved hydrogen sulfide. Gypsum blooms seem to have occurred at least as far back as the 1970s, and are associated with frequent mass mortalities of fish, plankton and benthos.

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“…Therefore, determining the maximum extent to which calcium sulfate dihydrate is soluble in pure water or other solutions is meaningful environmentally and industrially. A number of articles since 1901 have reported the solubility data of gypsum in pure water or other electrolyte solutions, but these data, found scattered as literature data of solubility of gypsum in Na, Cl, and Mg chloride salt solutions at ordinary temperatures, were mainly measured before 1990 by EDTA potentiometric titration for calcium analysis. − Besides, few investigators made efforts to measure or predict with the help of a chemical model the solubility of gypsum in AlCl 3 solutions. , …”

Section: Introductionmentioning

confidence: 99%

Effects of Na, Ca, Mg, and Al Chloride Salts on Dissolution and Phase Stability of Calcium Sulfate Dihydrate in Aqueous Solutions at 278.15 K to 308.15 K

2015

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Dissolution trend and solubility data of calcium sulfate dihydrate (CaSO 4 ·2H 2 O gypsum) in aqueous Na, Ca, Mg, and Al chloride salt solutions have been studied at 278.15 K to 308.15 K. The concentration ranges were up to 4.5 mol·L −1 for NaCl, 3.0 mol·L −1 for MgCl 2 , 2.0 mol·L −1 for CaCl 2 , and 1.6 mol·L −1 for AlCl 3 , respectively. Measurement results show that except for CaCl 2 , the other three salts allow the solubility of gypsum to rise a lot first and then descend smoothly after attaining the maximum. Because of common ions effect, the solubility of CaSO 4 ·2H 2 O drops sharply in CaCl 2 solution at low concentration and continues to fall almost linearly as concentration exceeds 0.2 mol•kg −1 . Impacts of Na, Mg, Al chloride salts on solubility of CaSO 4 ·2H 2 O are explained on the basis of dissolution and thermodynamic equilibrium. The solubility of CaSO 4 ·2H 2 O in AlCl 3 solution is highest compared with that in NaCl and MgCl 2 solution because two sulfur-bearing chemical complex Al(SO 4 ) 2 − (aq) and AlSO 4 + (aq) are expected to be formed in solution. Besides, a number of H + ions produced in AlCl 3 solution further promote the dissolution of CaSO 4 ·2H 2 O. In addition, it is demonstrated that CaSO 4 ·2H 2 O is fairly stable in the above chloride salts solution of high concentration (4.5 mol·L −1 for NaCl, 3.0 mol·L −1 for MgCl 2 , 2.0 mol·L −1 for CaCl 2 and 1.6 mol·L −1 for AlCl 3 ) for 2 weeks at 308.15 K by the evidence that no new peaks emerged in X-ray power diffraction results.

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Solubility of gypsum in sea water and sea water concentrates at temperatures from ambient to 65.degree.

Cited by 14 publications

References 4 publications

Diagenetic formation of gypsum and dolomite in a cold-water coral mound in the Porcupine Seabight, off Ireland

Diagenetic formation of gypsum and dolomite in a cold-water coral mound in the Porcupine Seabight, off Ireland

Sulfide irruptions and gypsum blooms in the Salton Sea as detected by satellite imagery, 1979–2006

Effects of Na, Ca, Mg, and Al Chloride Salts on Dissolution and Phase Stability of Calcium Sulfate Dihydrate in Aqueous Solutions at 278.15 K to 308.15 K

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