Ettringite precipitation

Abu Dhabi International With regard to the precipitation rate of ettringite from solution (stage 3), Baur et al. 22) measured the dissolutionprecipitation reaction rate between the solid ettringite and the aqueous • Ettringite precipitation ( SAVMIN™) • Aluminum added to water to form ettringite (calcium aluminum sulfate, Ca₆Al₂(SO₄)₃(OH)₁₂·26H₂O • Reaction at pH 11 -13 • Feasible for SO 4 < ~ 1,800 mg/l (gypsum solubility) • Sulfate removal to ~ 10’s mg/l - 000’s mg/l SO 4 • Aluminum form can be: Se hela listan på hindawi.com Abstract In the present study, experiments were conducted to optimize sulfate removal efficiency with ettringite precipitation from landfill leachate using The optimum pH for ettringite precipitation in all systems was found to be around 12.0. By the application of the method, 0.06 M initial sulphate concentration was reduced down to 60 mg/L for ettringite precipitation. The pilot plant was supplied by G.U.N.T. Gerätebau GmbH. A photograph of the plant in use with NaAlO 2 and lime and a close-up of the ettringite precipitates can be seen in Figures 1 and 2. The plant consists essentially of a raw water tank, a reactor tank followed by a (2016).

Go SPE Disciplines. Highlight matches. Any in SPE Disciplines (1) Conference. Abu Dhabi International With regard to the precipitation rate of ettringite from solution (stage 3), Baur et al. 22) measured the dissolutionprecipitation reaction rate between the solid ettringite and the aqueous • Ettringite precipitation ( SAVMIN™) • Aluminum added to water to form ettringite (calcium aluminum sulfate, Ca₆Al₂(SO₄)₃(OH)₁₂·26H₂O • Reaction at pH 11 -13 • Feasible for SO 4 < ~ 1,800 mg/l (gypsum solubility) • Sulfate removal to ~ 10’s mg/l - 000’s mg/l SO 4 • Aluminum form can be: Se hela listan på hindawi.com Abstract In the present study, experiments were conducted to optimize sulfate removal efficiency with ettringite precipitation from landfill leachate using The optimum pH for ettringite precipitation in all systems was found to be around 12.0.

Under conditions of extreme deterioration, and repeated wetting and drying, ettringite crystals can appear to completely fill voids 1.Introduction. Sulfate-resistant cements are manufactured in the absence or with very low proportions of C 3 A (0–5% in CEM I-SR []) to prevent the detrimental precipitation of ettringite (3CaO∙Al 2 O 3 ∙3CaSO 4 ∙32H 2 O). Ettringite precipitation Introduction.

Ettringite is a hydrous calcium aluminium sulfate mineral with formula: Ca6Al2(SO4)3(OH)12·26H2O. It is a colorless to yellow mineral crystallizing in the trigonal system. The prismatic crystals are typically colorless, turning white on partial dehydration.

With precipitation as ettringite, mine water sulphate concentration can be reduced to less than 200 mg/L. This is less than the drinking water guideline in Finland, which is 250 mg/L sulphate (Directive 98/83/EC). When ettringite precipitation is used for waters with high sulphate concentration (>3000 mg/L), it may be economical to use traditional lime In this study, the principles of chemical precipitation of sulfate which is based on the formation of ettringite, a double salt with the formula Ca3Al2O6.3CaSO (4).32H (2)O are evaluated. The Al-2 A novel sulfate removal process via ettringite precipitation was developed by dissolving ettringite and recycling Al 3+ under low pH condition. Effects of solid to liquid ratios, pH and temperature on ettringite dissolution, Al recovery and transformation of precipitates were investigated by batch experiments.

Description of the technology. Known processes for sulphate removal with ettringite precipitation contain the main unit Development stage. Known 2016-10-01 · Sulphate precipitation as ettringite is a modification of high pH lime precipitation (Geldenhuys et al., 2003, Tolonen et al., 2015). With precipitation as ettringite, mine water sulphate concentration can be reduced to less than 200 mg/L. This is less than the drinking water guideline in Finland, which is 250 mg/L sulphate (Directive 98/83/EC). Ettringite precipitation applied to catalytic-air oxidized sample provided up to 99.5% sulphate removal. Residual sulphate concentration around 20 mg/L was consistent with the literature results 2019-03-05 · A novel sulfate removal process via ettringite precipitation was developed by dissolving ettringite and recycling Al 3+ under low pH condition.
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When ettringite precipitation is used for waters with high sulphate concentration (>3000 mg/L), it may be economical to use traditional lime A novel sulfate removal process via ettringite precipitation was developed by dissolving ettringite and recycling Al 3+ under low pH condition.

Sulfate-resistant cements are manufactured in the absence or with very low proportions of C 3 A (0–5% in CEM I-SR []) to prevent the detrimental precipitation of ettringite (3CaO∙Al 2 O 3 ∙3CaSO 4 ∙32H 2 O). Ettringite precipitation Introduction. Ettringite precipitation (addition of lime and Al (OH) 3) can be used to remove sulphate and heavy metals. Description of the technology. Known processes for sulphate removal with ettringite precipitation contain the main unit Development stage.
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More than 93% of the sulfate ions were removed by ettringite precipitation, whereas lime precipitation removed less than 28% under the same conditions due to the difference in their solubility. The effect of Mg 2+ on sulfate removal by ettringite precipitation was investigated, and the process was optimized in the absence and presence of Mg 2+. In the absence of Mg 2+ , the optimum conditions with sulfate removal of 99.7% were obtained at calcium-to-sulfate ratio of 3.20, aluminum-to-sulfate ratio of 1.25 and pH of 11.3 using response surface methodology. The start of ettringite precipitation is defined as the moment when conductivity starts to drop. The temperature was kept at 25 °C and experiments were conducted in a 400 mL-capacity jacketed glass reactor containing a Nalgene surface.

Ettringite precipitation can reduce the sulphate concentration to ca.

Residual sulphate concentration around 20 mg/L was consistent with the literature results 2019-03-05 · A novel sulfate removal process via ettringite precipitation was developed by dissolving ettringite and recycling Al 3+ under low pH condition. Effects of solid to liquid ratios, pH and temperature on ettringite dissolution, Al recovery and transformation of precipitates were investigated by batch experiments. 2017-07-01 · However, the effects of Mg 2+ on ettringite precipitation are scarcely reported, and it should be essential for process design and very useful for understanding the precipitation behavior in real wastewater rich in Mg 2+ and sulfate. The aims of this study are to optimize sulfate removal and investigate the effect of Mg 2+ on the ettringite 2017-07-01 · The effect of Mg2+ on sulfate removal by ettringite precipitation was investigated, and the process was optimized in the absence and presence of Mg2+. In the absence of Mg2+, the optimum conditions with sulfate removal of 99.7% were obtained at calcium-to-sulfate ratio of 3.20, aluminum-to-sulfate ratio of 1.25 and pH of 11.3 using response surface methodology.