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.

Nov 5, 2019 The diffusion-precipitation mechanism is translated by a rough chemical model. The resulting local volume fraction of ettringite is estimated by a.

The aim of this research was to investigate sulphate removal from mine water by precipitation as ettringite (Ca6Al2(SO4)3(OH)12·26H2O) and the utilisation of the precipitate as a sorbent for arsenate removal. The mine water sulphate concentration was reduced by 85-90% from the initial 1400 mg/L during ettringite precipitation depending on the treatment method. The precipitation conditions Chemical, physical and biological technologies for removal of sulphate from mine tailings pond water (8 g SO 4 2-/L) were investigated. Sulphate concentrations of approximately 1,400, 700, 350 and 20 mg/L were obtained using gypsum precipitation, and ettringite precipitation, biological sulphate reduction or reverse osmosis (RO) after gypsum pre-treatment, respectively.

Ettringite precipitation

The products identified were similar to the ones found when PC, attacked by sulfates, cracks in response to their formation [ 42 , 43 ]. ettringite stream gypsum Prior art date 2015-07-22 Application number PCT/ZA2016/050025 Other languages French (fr) Other versions WO2017015678A3 (en Inventor Martha Hendriette Kotze Original Assignee Mintek Priority date (The priority date is an assumption and is not a legal conclusion. Ettringite precipitation can be applied for removal of sulfate from textile wastewater (), acidic mine drainage (), tap water () and as well as heavy metals removal Jan 1, 2018 A portion of the ettringite sludge from the ettringite precipitation reactor, Reactor 3 , is recycled and mixed with the feed water in the ettringite Calcium concentration in the ettringite precipitation step is an important control parameter, as ettringite precipitation consumes 6 calcium ions per ettringite Mar 27, 2021 Study on SO4 2- Removal with Ettringite Precipitation Approach in Wet. Desulfurization of Firing-Power Plant. To cite this article: Guangling Niu Read chapter ETTRINGITE FORMATION IN STABILIZED SOILS: TRB's National Cooperative Highway Research Program (NCHRP) Web-Only Document 145: May 20, 2020 Ettringite precipitation was implemented as an alternative to lime precipitation to process sulfate-rich brine resulting from the NF operation. More Sep 19, 2019 The ettringite precipitation is a modification of high pH lime precipitation (Tolonen et al. 2016), and judging from the lower solubility of ettringite, Ettringite is a hydrous calcium aluminium sulfate mineral with formula: Ca6Al2( SO4)3(OH)12·26H2O.

Chemical precipitation. Sulphide precipitation; Precipitation with barium salts; Ettringite precipitation; Iron co-precipitation; Ion exchange; Membrane processes; Sulphate reduction in reactors; Treatment/disposal of water treatment residues; Passive treatment technologies. Aerobic constructed wetlands; Anaerobic constructed compost wetlands

It is a colorless to yellow mineral crystallizing in the trigonal chloride all remove sulfate as ettringite, with aluminum chloride removing sulfate to the lowest residual chemical precipitation processes, ettringite precipitation. Oct 1, 2016 Different versions of the precipitation as ettringite have been patented (Nevatalo et al., 2014, Ramsay, 2001).

the ettringite precipitation stage, in comparison to the other two liquid reagents. Table 4 contains the test results for the solid reagents. It is surprising to find that products based on crystalline aluminium hydroxide (Hydrargillite), even at relatively high doses, are not appropriate for ettringite precipitation…

Other constituents were in liquid phase, also gibbsite and portlandite.

Abu Dhabi International The determined reconstruction time for ettringite lay within 1.2-4 years, which resulted in a dissolution-precipitation rate of 10 À 12.2 to 10 À 11.5 mol m À 2 days À 1 . For monosulfate, the data for the two series for 45 Ca agreed well, both resulting in a reconstruction time around 500 days. Se hela listan på hindawi.com 2000-02-28 · ettringite could reduce the protection the air void system affords against freeze-thaw damage (see discussion of freeze-thaw resistance below).
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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 consumed by ettringite precipitation. Namely, under these conditions, the supersaturation level is the highest for ettringite which is then the more stable phase.

Effects of solid to liquid ratios, pH and temperature on ettringite dissolution, Al recovery and transformation of precipitates were investigated by batch experiments. 2016-10-01 · The mine water sulphate concentration was reduced by 85-90% from the initial 1400 mg/L during ettringite precipitation depending on the treatment method.
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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).

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.

(2016). Sulphate control by ettringite precipitation in textile industry wastewaters. Environmental Technology: Vol. 37, 9TH IWA SYMPOSIUM ON WASTE MANAGEMENT PROBLEMS IN AGRO-INDUSTRIES-AGRO’2014, pp. 446-451.

Known processes for sulphate removal with ettringite precipitation contain the main unit Development stage.

During ettringite precipitation, contaminants such as nitrate, chloride, fluoride, boron and 27 Mar 2021 Study on SO4 2- Removal with Ettringite Precipitation Approach in Wet. Desulfurization of Firing-Power Plant. To cite this article: Guangling Niu Calcium concentration in the ettringite precipitation step is an important control parameter, as ettringite precipitation consumes 6 calcium ions per ettringite Overview of Ettringite Precipitation Process for Sulfate Removal from Mine Water.