The crystal growth of gypsum in an ammoniacal environment

Kagawa, M.; Sheehan, M.E.; Nancollas, G.H.

doi:10.1016/0022-1902(81)80149-2

Cited by 14 publications

(8 citation statements)

References 6 publications

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“…For this water source, the thermodynamically estimated mass of mineral salts that may precipitate (2.92–3.06 g/L for pH range of 5–8) is dominated by gypsum (≥92%). Gypsum precipitation is only weakly pH dependent, as demonstrated in previous studies of bulk precipitation of gypsum , .…”

Section: Resultssupporting

confidence: 69%

Reverse Osmosis Desalting of Inland Brackish Water of High Gypsum Scaling Propensity: Kinetics and Mitigation of Membrane Mineral Scaling

Rahardianto

McCool

Cohen

2008

Environ. Sci. Technol.

115

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The potential for mineral scaling that may limit the generation of new potable water resources by reverse osmosis (RO), from inland brackish water of high gypsum scaling propensity, was experimentally explored via flux decline measurements and real-time RO membrane surface imaging. Antagonistic gypsum and calcium carbonate scaling kinetics were demonstrated for high-sulfate brackish water desalting. RO scaling studies with brackish water from the California San Joaquin Valley (approximately 10 000 mg/L total dissolved solids) revealed that membrane gypsum scaling was increasingly retarded with rising bicarbonate concentrations. Crystal growth rate, fractional membrane scale coverage, and flux decline decreased by up to about 63, 78, and 73%, respectively, as the bicarbonate concentration increased, at the membrane surface, from < 0.01 to 7.81 mM, for a gypsum saturation index of 2. Inhibition of gypsum crystal growth was attributed to bicarbonate adsorption onto the crystal surfaces, and CaCO3 scaling was undetected even up to a calcite saturation index of approximately 16. Given the suppression of gypsum scaling by bicarbonate, it is essential to considerthis effect in the conventional practice of pH adjustment to suppress CaCO3 scaling. The present results suggest that antagonistic and synergistic mineral crystallization kinetics effects are important for optimizing scale-control strategies (e.g., acid and antiscalants addition to the RO feed).

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Section: Resultssupporting

confidence: 69%

Reverse Osmosis Desalting of Inland Brackish Water of High Gypsum Scaling Propensity: Kinetics and Mitigation of Membrane Mineral Scaling

Rahardianto

McCool

Cohen

2008

Environ. Sci. Technol.

115

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“…(a)) needs discussion. There are many studies of calcium sulfate dihydrate crystallization that do not show the formation of spherulitic crystals, either in homogeneous crystallization with or without any additives or on foreign surfaces . On the other hand, there are a number of studies that note their formation in the absence of additives during homogeneous or heterogenous crystallization on foreign surfaces such as heat exchangers or reverse osmosis membranes, or in the presence of additives, similar to the present investigation.…”

Section: Resultssupporting

confidence: 61%

Effects of crystal habit modifiers on the morphology of calcium sulfate dihydrate grown in strong CaCl₂‐HCl solutions

Feldmann

Demopoulos

2013

J of Chemical Tech & Biotech

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BACKGROUND This work deals with the effect of several additives on the morphology of calcium sulfate dihydrate (DH) crystals, produced by reactive crystallization involving strong CaCl2–HCl solutions. Experiments were conducted at 40 °C under various conditions, namely homogeneous and seeded (heterogeneous) crystallization in CaCl2/HCl solutions ranging from very dilute (0.42 mol L−1/0.04 mol L−1) to very concentrated (1.8 mol L−1/6.3 mol L−1). RESULTS In the absence of additives a distinct difference in crystal morphology was observed depending on solution composition. Homogeneously formed DH crystals from dilute solution were in the form of needles. DH crystals formed in concentrated acid solution were thick elongated plates. The most influential additives in concentrated solutions were CTAB (cetyltrimethylammoniumbromide), PAA (polyacrylic acid) and PVS (polyvinyl sulfonic acid). CTAB favoured formation of industrially interesting thick slab crystals. In contrast PAA favoured the formation of elongated and thinner crystals as a result of preferential crystal plane adsorption. PVS had a detrimental effect on DH crystal nucleation and growth explained by its polymeric structure. CONCLUSION Apart from PVS, CTAB and PAA no influence was seen for the majority of additives tested. This was attributed to lack of ionization caused by the highly acidic solutions. © 2013 Society of Chemical Industry

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“…However, if suitable crystallization seeds are introduced, heterogeneous precipitation will be promoted. Previous studies found that anhydrite, hemihydrate, gypsum, barite and calcite substrates encourage heterogeneous precipitation of gypsum (Gill and Nancollas, 1979;Kagawa et al, 1981). In this study precipitation of gypsum was promoted by the presence of calcite and aragonite.…”

Section: Lack Of Available Crystallization Seedsmentioning

confidence: 65%

“…Therefore, these studies focused on gypsum precipitation from solutions with relatively low ionic strength, similar to the conditions in the industry (Edinger, 1973;Van Rosmalen et al, 1981;Christoffersen et al, 1982;Cody and Cody, 1989). Most of these studies were conducted in solutions that contain equivalent concentrations of Ca 2+ and SO 4 2À (Liu and Nancollas, 1970;Smith and Sweett, 1971;Gill and Nancollas, 1979;Kagawa et al, 1981;Van Rosmalen et al, 1981;Christoffersen et al, 1982;Witkamp et al, 1990;He et al, 1994b). The few studies that examined gypsum nucleation and crystal growth in high ionic strength conditions, did so in solution of ionic strength of only up to 6 m (mol kg H 2 O À1 ) (He et al, 1994a,b), which is still significantly lower than the ionic strength of the Dead Sea brine (10 m).…”

Section: Introductionmentioning

confidence: 98%

Kinetics of gypsum nucleation and crystal growth from Dead Sea brine

Reznik

Gavrieli

Ganor

2009

Geochimica et Cosmochimica Acta

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The crystal growth of gypsum in an ammoniacal environment

Cited by 14 publications

References 6 publications

Reverse Osmosis Desalting of Inland Brackish Water of High Gypsum Scaling Propensity: Kinetics and Mitigation of Membrane Mineral Scaling

Reverse Osmosis Desalting of Inland Brackish Water of High Gypsum Scaling Propensity: Kinetics and Mitigation of Membrane Mineral Scaling

Effects of crystal habit modifiers on the morphology of calcium sulfate dihydrate grown in strong CaCl₂‐HCl solutions

Kinetics of gypsum nucleation and crystal growth from Dead Sea brine

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The crystal growth of gypsum in an ammoniacal environment

Cited by 14 publications

References 6 publications

Reverse Osmosis Desalting of Inland Brackish Water of High Gypsum Scaling Propensity: Kinetics and Mitigation of Membrane Mineral Scaling

Reverse Osmosis Desalting of Inland Brackish Water of High Gypsum Scaling Propensity: Kinetics and Mitigation of Membrane Mineral Scaling

Effects of crystal habit modifiers on the morphology of calcium sulfate dihydrate grown in strong CaCl2‐HCl solutions

Kinetics of gypsum nucleation and crystal growth from Dead Sea brine

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Effects of crystal habit modifiers on the morphology of calcium sulfate dihydrate grown in strong CaCl₂‐HCl solutions