Effects of ultrasonic treatment on zeolite NaA synthesized from by-product silica

Vaičiukynienė, Danutė; Kantautas, Aras; Vaitkevičius, Vitoldas; Jakevicius, L.; Rudžionis, Žymantas; Paškevičius, Mantas

doi:10.1016/j.ultsonch.2015.06.001

Cited by 33 publications

(9 citation statements)

References 18 publications

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“…Furthermore, many manufacturers use an amount of hexafluorosilicic acid (H 2 SiF 6 ) in excess of the amount that the added aluminum hydroxide would fully react, and the yield of aluminum fluoride would increase [11][12][13][14][15][16][17][18]. However, very low pH values of the obtained system are produced, leading to the strong chemisorption properties of silica gel for fluoride ions [17,[19][20][21]. For this reason, the purification of this material has become a great challenge [19].…”

Section: Introductionmentioning

confidence: 99%

The Effect of Various Hydroxide and Salt Additives on the Reduction of Fluoride Ion Mobility in Industrial Waste

et al. 2021

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In this work, the influence of various hydroxide and salt additives on the removal of F− ions from silica gel waste, which is obtained during the production of AlF3, was examined. The leaching of the mentioned ions from silica gel waste to the liquid medium was achieved by the application of different techniques: (1) leaching under static conditions; (2) leaching under dynamic conditions by the use of continuous liquid medium flow; and (3) leaching in cycles under dynamic conditions. It was determined that the efficiency of the fluoride removal from this waste depends on the w/s ratio, the leaching conditions, and the additives used. It was proven that it is possible to reduce the concentration of fluorine ions from 10% to <5% by changing the treatment conditions and by adding alkaline compounds. The silica gel obtained after the leaching is a promising silicon dioxide source.

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Section: Introductionmentioning

confidence: 99%

The Effect of Various Hydroxide and Salt Additives on the Reduction of Fluoride Ion Mobility in Industrial Waste

et al. 2021

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“…In the case of success, silica gel with a low content of F − ions and water contaminated with F − ions can be obtained. The silica gel with a lower content of F − ions (<5%) can be used as an SiO 2 source in some industries [25][26][27][28][29], and only LTD "Alufluor AB" [30] sells this product worldwide. Meanwhile, wastewater contaminated with F − ions can be neutralized by adding Ca(OH) 2 or CaCO 3 [31,32].…”

Section: Introductionmentioning

confidence: 99%

“…As a matter of fact, in the context of reducing environmental issues and enhancing economic benefits, technologies for converting waste materials into products of commercial value are in great demand [14,17,18,29,34,38]. However, the literature concerning the successful application of silica gel waste contaminated with F − ions is scarce.…”

Section: Introductionmentioning

confidence: 99%

The Prospective Approach for the Reduction of Fluoride Ions Mobility in Industrial Waste by Creating Products of Commercial Value

et al. 2019

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In this work, we present the possibility to reduce the amount of fluoride ions in silica gelwaste by using different techniques or to immobilize these ions by creating products ofcommercial value. The leaching of fluoride ions from silica gel waste to the liquid medium wasdone under static and dynamic conditions. It was determined that the removal of fluoride ionsfrom this compound depends on various factors, such as dissociation, solubility, the w/s ratio,reaction temperature, leaching conditions, the adsorption properties of silica gel waste, and others.The obtained results showed that, by applying different techniques, the quantity of fluoride ionscan be reduced by 60%, while obtained water was neutralized by calcium hydroxide.Additionally, it was determined that silica gel waste is a promising raw material for thehydrothermal synthesis of a stable compound containing fluoride ions – cuspidine.

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“…To prevent leakage, the fluorine can be bound into stable compounds. Silica-gel waste can be used as a source of silicon dioxide for the synthesis of calcium silicate hydrates 11–16 . This reaction is carried out in hydrothermal conditions and can also bound the pollutants of the silica-gel into stable calcium fluoride and calcium-silicate-aluminate compounds.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of wollastonite from AlF3-rich silica gel and its hardening in the CO2 atmosphere

Gineika

Šiaučiūnas

Baltakys

2019

Sci Rep

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This work combines some aspects of eco-friendliness: consumption of toxic waste, cutback of energy consumption during the synthesis of the binding material, reduction of CO2 emission by using less CaCO3 in the raw meal, and consumption of carbon dioxide. In the study, the kinetics of two-step synthesis of wollastonite from CaO and AlF3 production waste, namely, silica gel, its carbonisation process and the mechanical properties of obtained samples were investigated. According to XRD and DSC data, the optimal temperature in the mixture with CaO/(Al2O3 + SiO2) = 1 for the hydrothermal synthesis of the wollastonite precursors is 130 °C: F−–containing compounds were bound into katoite and cuspidine, and portlandite reacted completely within 8 h. The optimal temperature for wollastonite formation is 900 °C, but fluormayenite, cuspidine, and the traces of larnite form as well. During the curing in the CO2 atmosphere, wollastonite and larnite reacted completely and formed calcite, vaterite, and amorphous CaCO3. Cuspidine also participates in the carbonisation process and, in addition to amorphous SiO2, it releases fluorite, which contributes to the total compressive strength of the products. The values of the compressive strength (10–15 MPa) in the wollastonite-sand samples match the requirements for the belite and special low-heat cements.

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Effects of ultrasonic treatment on zeolite NaA synthesized from by-product silica

Cited by 33 publications

References 18 publications

The Effect of Various Hydroxide and Salt Additives on the Reduction of Fluoride Ion Mobility in Industrial Waste

The Effect of Various Hydroxide and Salt Additives on the Reduction of Fluoride Ion Mobility in Industrial Waste

The Prospective Approach for the Reduction of Fluoride Ions Mobility in Industrial Waste by Creating Products of Commercial Value

Synthesis of wollastonite from AlF3-rich silica gel and its hardening in the CO2 atmosphere

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