After partial sulphate removal, a smaller dosage of the more expensive aluminium chemical is required for the ettringite precipitation step. DOI: 10.1590/0104-6632.20180353S20170528 Corpus ID: 104463417. STATISTICAL OPTIMIZATION OF ETTRINGITE PRECIPITATION IN LANDFILL LEACHATE @article{Aygun2018STATISTICALOO, title={STATISTICAL OPTIMIZATION OF ETTRINGITE PRECIPITATION IN LANDFILL LEACHATE}, author={A. Aygun and S. Dogan and M. E. Argun}, journal={Brazilian Journal of Chemical Engineering}, year={2018}, volume={35}, pages={969-976} } 2000-02-28 · ettringite could reduce the protection the air void system affords against freeze-thaw damage (see discussion of freeze-thaw resistance below). Ettringite formed by dissolution and recrystallization in void spaces and cracks is often referred to as “secondary ettringite.” Secondary ettringite is not detrimental to concrete performance.
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). 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.
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.
A portion of the ettringite sludge from the ettringite precipitation reactor, Reactor 3, is recycled and mixed with the feed water in the ettringite dissolution reactor, Reactor 1 to In the present study, experiments were conducted to optimize sulfate removal efficiency with ettringite precipitation from landfill leachate using Response Surface Methodology (RSM) and Central Composite Design (CCD). The statistical analysis of the results showed that the operating parameters such as molar rates of Ca/ SO4 and Al/SO4, and pH had a significant effect on sulfate removal ettringite precipitation has been found to be around 12,0 (Kabdaşlı et al., 2015). After the precipitation reaction is complete, the ettringite solids are separated from the feed water, filtered and thickened. Due to the high sulphate removal efficiencies of 85-90 % (Tolonen et al., 2016) and of over 95-98 % (Fang et al., 2018) 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 Abstract In the present study, experiments were conducted to optimize sulfate removal efficiency with ettringite precipitation from landfill leachate using ettringite precipitation Source. OnePetro (1) Date. 2020 (1) to.
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…
Ettringite precipitation can be applied for removal of sulfate from textile wastewater (Tunay et al., 2014), acidic mine drainage (Madzivire et al., 2010), tap
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Ettringite formation can also provide a polishing effect, allowing precipitation of difficult-to-remove metals such as chromium, arsenic, selenium and cadmium, often below their respective analytical detection limits.
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Ettringite precipitation was implemented as an alternative to lime precipitation to process sulfate-rich brine resulting from the NF operation. 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.
gypsum and ettringite precipitation.
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Therefore, it can be assumed that the effect of ettringite precipitation on the rheological properties of the cement paste is of exponential order. With increasing ettringite content during hydration, the effect on the flow behavior becomes much larger. WO2017015678A2 PCT/ZA2016/050025 ZA2016050025W WO2017015678A2 WO 2017015678 A2 WO2017015678 A2 WO 2017015678A2 ZA 2016050025 W ZA2016050025 W ZA 2016050025W WO 2017015678 A2 WO2017015678 A2 WO 2017015678A2 Authority WO WIPO (PCT) Prior art keywords sulphate calcium ettringite stream gypsum Prior art date 2015-07-22 Application number … 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.
Effects of solid to liquid ratios, pH and temperature on ettringite dissolution, Al recovery and transformation of precipitates were investigated by batch experiments.
An Aspen computer simulation. Ettringite precipitation can be considered as responsible for these expansions.