Surface properties of kaolin and illite suspensions in concentrated calcium hydroxide medium

Konan, Koffi Léon; Peyratout, Claire; Bonnet, Jean-Pierre; Smith, Agnès; Jacquet, Alain; Magnoux, P.; Ayrault, Philippe

doi:10.1016/j.jcis.2006.10.085

Cited by 57 publications

(53 citation statements)

References 24 publications

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“…[40] Thus, iron leach from fly ash particles was expected to contain more Fe 3þ . In addition, spectral features suggest that all fly ash samples have exposed edge sites with Al-OH and Si-OH bond terminals, [43] which is consistent with literature reports of silica and mullite (3Al 2 O 3 Á2SiO 2 ) content in fly ash. [44] The formation of mullite and silica in fly ash has been suggested to follow a two-step mechanism during the combustion process, where kaolinite (Al 2 where the loss of the well-crystallised aluminosilicate clay minerals leading to mullite and silica has been suggested to decrease the stability of the mineral, which can lead to faster dissolution rates in an acidic media.…”

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confidence: 88%

Comparative evaluation of iron leach from different sources of fly ash under atmospherically relevant conditions

et al. 2016

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Environmental context. Iron, a limiting nutrient of plankton in the ocean, is deposited to the sea from atmospheric aerosols. In particular, atmospheric acidic conditions promote dissolution of iron from fly ash, a byproduct of coal-fired power plants. Here, we report that the iron leached from fly ash depends on its source region, and that the type of combustion process may influence the iron species mobilized.Abstract. Fly ash, an iron-containing by-product of coal-fired power plants, has been observed in atmospheric aerosol plumes. Under the acidic atmospheric conditions resulting from the uptake of atmospheric gases, iron leached from fly ash can impact global biogeochemical cycles. However, the fly ash source region, as well as its generating power plant, plays an important role in the amount, speciation and lability of iron. Yet no comparative studies have been made on iron leached from fly ash from different sources. This study reports the iron mobilisation by proton-promoted dissolution from wellcharacterised fly ash samples from three distinctive locations: the USA Midwest, north-east India and Europe. In addition, pH dependency was also investigated. Proton-promoted dissolution showed a variability between source regions with a relative iron leach in the order USA Midwestern . north-east Indian . European ash. In addition, the initial rate of iron leach suggests that source region is indeed a determining factor in the iron leaching capacity of fly ash, because dissolution from Midwestern fly ash is also faster than both European and Indian ash. Finally, the combustion process of fly ash proved to be significant for the iron speciation, given that well-combusted fly ash samples leached mostly Fe 3þ rather than bioavailable Fe 2þ . The role of fly ash should therefore be taken into account in order to better understand the effects of combustion particles in atmospheric iron deposition.

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confidence: 88%

Comparative evaluation of iron leach from different sources of fly ash under atmospherically relevant conditions

et al. 2016

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“…at 550 °C, probably due to the partial collapse of the structure. The true density of the starting clayey material treated in NaCl solution is close to those given in the work of Konan et al [24]. For an illite it was about 2630 kg.m -3 whereas for a montmorillonite it was about 2300 kg.m -3 , and for a kaolinite it was about 2700 kg.m -3 .…”

Section: Fig (2)supporting

confidence: 87%

Effects of Heating and Acid Activation on the Structure and Surface Properties of a Kaolinite-illite-smectite Clayey Mixture

Landoulsi¹

2013

TOMPJ

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Abstract:This work aims at studying the effects of heat treatment and acid activation on the surface properties of a mixture of kaolinite-illite-smectite clay minerals collected from North Est of Tunisia. The raw material was characterized by various analytical and spectroscopic techniques such as XRD, FT-IR, TG-DSC, and N 2 physical adsorption.The true density of starting raw material increased from 2580 to 2609 kg.m 3 , while the surface area, S BET , decreased from 70.7 to 35.3 m 2 .g -1 upon heat treating at 550°C for 1 h. Acid activation of heat treated material led to partial dissolution of the octahedral sheets by interlayer and edge attack, the formation of amorphous silica and an overall structural degradation. Dynamic vapour Sorption (DVS) measurement revealed that the surface energy of the system increased after acid activation and with the acid treatment time. These structural/surface changes translated in higher negative zeta potential (

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“…Other types of layers are chemically bonded parallel to each tetrahedral sheet to form the unit layer for a variety of clays. For example, kaolinite is structured as repeating units of an octahedral aluminum-hydroxyl sheet bonded to the tetrahedral silicon-oxygen sheet, as illustrated in Figure 1 by Konan, et al (2007), whereas the octahedral Al-OH sheet is sandwiched between two tetrahedral Si-O sheets for montmorillonite and illite. Clays have a large surface area to volume ratio that facilitates a variety of interactions with themselves as well as with aqueous species in the slurry (Singer & Munns, 1996;Giese, 2002).…”

Section: Size Classificationmentioning

confidence: 99%

Current state of fine mineral tailings treatment: A critical review on theory and practice

Wang

Harbottle

Liu

et al. 2014

Minerals Engineering

344

169

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Highlights Presented facts on escalating generation of fine mineral tailings worldwide.  Overview of coal, alumina, oil sands, and base metals tailings characteristics.  Reviewed theoretical and industrial developments for tailings management.  Determined numerous knowledge gaps between current theories and practices.  Identified opportunities for improvement towards more sustainable practices. Graphical AbstractEvolution of fine mineral tailings treatment objectives.Figures "Flocculated solids" and "Stackable solids" are adopted from Alamgir, et al. (2012), permission pending. The last figure "Reclaimed land" is adopted from Golder Associates (2009), permission pending. AbstractThe mining industry produces fluid fine mineral tailings on the order of millions of tonnes each year, with billions of tonnes already stored globally. This trend is expected to escalate as demand for mineral products continues to grow with increasingly lower grade ores being more commonly exploited by hydrometallurgy. Ubiquitous presence and enrichment of fine solids such as silt and clays in fluid fine mineral tailings prevent efficient solid-liquid separation and timely re-use of valuable process water. Long-term storage of such fluid waste materials not only incurs a huge operating cost, but also creates substantial environmental liabilities of tailings ponds for mining operators. This review broadly examines current theoretical understandings and prevalent industrial practices on treating fine mineral tailings for greater water recovery and reduced environmental footprint of mining operations.

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Surface properties of kaolin and illite suspensions in concentrated calcium hydroxide medium

Cited by 57 publications

References 24 publications

Comparative evaluation of iron leach from different sources of fly ash under atmospherically relevant conditions

Comparative evaluation of iron leach from different sources of fly ash under atmospherically relevant conditions

Effects of Heating and Acid Activation on the Structure and Surface Properties of a Kaolinite-illite-smectite Clayey Mixture

Current state of fine mineral tailings treatment: A critical review on theory and practice

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