Sericite Clay Research Articles

Influence of particle fluorination on the stability of honey foam

Honey foam has applications in the food, cosmetic, and pharmaceutical industries. For example, honey foam can be used in bread or biscuit spread (food industry), as a carrier of topical bioactive ingredients (cosmetic industry), or as a carrier of drugs (pharmaceutical industry). However, the conditions for obtaining a stable honey foam remain unclear. In this study, we investigated the influence of particle fluorination on honey foam volume and foam stability by aerating natural (unadulterated) honey with fluorinated fumed silica (50%–75% SiOH) or fluorinated sericite clay (PF-5–PF-12) particles. Higher foam volume (≤4.3 cm3) and foam stability (up to a year) were observed with the least (75% SiOH) fluorinated fumed silica particles, while lower foam volume and foam stability were observed with the moderately (59% SiOH) and most (50% SiOH) fluorinated fumed silica particles. In contrast, regardless of the degree of fluorination, the fluorinated sericite clay particles yielded little (<1 cm3) and unstable foam that collapsed completely within 4 weeks of preparation. Therefore, with respect to honey foam stabilization, fluorinated fumed silica particles are superior to fluorinated sericite clay particles. These foams can be used for topical formulation of cosmetic and pharmaceutical products, and our findings will guide future stabilization of honey foam for target applications.

Overcoming coffee-stain effect by particle suspension marble evaporation

One disadvantage of using the hydrophobic surface technique to suppress coffee-stain effect is that it requires hydrophobization of a relatively large area of hydrophilic surface. The opposite technique, which involves coating a particle suspension with powdered hydrophobic particles can perhaps be used to overcome this limitation, but has not been explored. Herein, we explored this technique by evaporating hydrophobic particle-coated aqueous suspensions of hydrophilic 100% SiOH fumed silica particles on hydrophilic glass slides and examining the particle films left. Various suspensions (1–5 wt%) of hydrophilic 100% SiOH silica particles were coated with either hydrophobic Aerosil® R 202 fumed silica or PF-12 fluorinated sericite clay particles and then allowed to evaporate on hydrophilic glass slides. The particle films left after complete evaporation were compared with those left by the corresponding uncoated particle suspensions. Visual observation and optical microscopy revealed that evaporation of the uncoated particle suspensions produced the so-called “coffee-stain” while that from the coated suspensions did not produce the effect, but rather gave a spot-like particle deposit. This shows that encapsulating particle suspensions in hydrophobic particles before evaporation prevents coffee-stain formation.

Removal of emerging micropollutants from water using hybrid material precursor to natural sericite clay

The occurrence of a wide range of micropollutants in natural aquatic environment has been reported in different parts of the world. These compounds are harmful for the aquatic life and human beings. Diclofenac and clofibric acid are the two common toxic micropollutants due to very large production and high consumption by humans. The present communication addresses the removal of diclofenac and clofibric acid from aqueous solutions using the hybrid material obtained by incorporating 3-aminopropyltriethoxysilane (APTES) onto the activated sericite clay. Initially, sericte clay was treated for activation and further modified with organosilane to obtain hybrid material. The materials were characterized using SEM, BET surface area, XRD, and FT-IR analyses.SEM and BET surface area analyses showed that the textural property of sericite clay was greatly changed after activation and the surface area was immensely increased from 3.65 to 62.92 m2/g. The organosilane was anchored on the activated clay and confirmed with FTIR analysis. Batch adsorption experiments showed that the diclofenac and clofibric acid removal is maximum at pH 6.0 to7.0 and the adsorption of these two micropollutants were observed to be very fast and the time dependent adsorption data were best fitted to pseudo-second order kinetic model. The maximum adsorption capacity of diclofenac and clofibric acid using APTES-sericite hybrid material was found to be 1.868 and 1.749 mg/g, respectively. Furthermore, the loading capacities of the column packed with APTES-sericite hybrid material were found to be 0.789 and 1.095 mg/g. Therefore, this study indicated that the APTES-sericite hybrid material must be an useful material for the effective removal of diclofenac and clofibric acid from aqueous waste.

Hydrometallurgical Investigation of Sericite Clay for Extraction of Alumina and Potash Under Controlled Conditions

The current study investigates sericite clay as an alternative source of potash and alumina. The alumina and potash content in the sericite is approximately 35 and 10%, respectively, compared with 50–55% in bauxite ore. Muscovite and illite phases are stable, and direct leaching is found to be ineffective. Here, planetary ball milling was performed, which provided dissociation of stable phases to relatively reactive phases. The milling led to a five-fold increase in the surface area, resulting in enhanced leaching kinetics even at low acid concentration. The statistical design obtained optimal conditions of 8 h of milling followed by leaching in 1.73 M HCl at 75 °C, yielding 82% alumina extraction in precipitate with 85% purity in γ-alumina form and 63% potassium dissolution in sylvinite phase. The yield of the precipitate was ~65–68%, and the acid leach residue contained primarily silica.

Liquid marbles as microreactors for qualitative and quantitative inorganic analyses

Conventional qualitative analysis of ions from inorganic salts and acid–base and redox titrations require relatively large volumes of solution and hence require more reagent and generate relatively large amount of waste. Liquid marbles can be used to cut down the volume of solution and by extension the amount of reagent and volume of waste generated. Liquid marbles were used for qualitative analysis of ions from inorganic salt solutions and acid–base and redox titrations. This was compared with the conventional methods which require milliliters of solution. Fumed silica or fluorinated sericite clay particles of varying degrees of hydrophobicity were used to prepare the marbles. A drop of a test reagent was then placed on the marble, merging with it and initiating a chemical reaction. The characteristic reactions between a salt solution and a test reagent in the marbles were observed provided the reaction was clearly marked by a color change. Concentrations, calculated from the volume at the end-point, compared closely (p ≤ 0.05) with the known ones as well as those calculated from the bulk titration method that requires milliliters of solution. This indicates that the liquid marble method which rather requires microliters of solutions is reliable. These findings are especially important in microfluidics which utilizes microliters of solutions.

The effect of vitreous phase on mullite and mullite-based ceramic composites from kaolin wastes as by-products of mining, sericite clays and kaolinite

Mullite precursors were prepared using kaolin waste, sericite clay containing kaolinite and industrial kaolin with addition of alumina in a wet medium to synthesize mullite (72 wt% Al2O3 and 28 wt% SiO2). Uniaxial pressed bars of the powdered mullite precursors were fired in the range 1400–1600 °C with soaking times 30–120 min. The resultant materials were studied by XRD and SEM-EDX. Bulk densities, apparent porosities and flexural strengths in four points were determined in the fired bars at 1500, 1550 and 1600 °C. It was concluded that the thermal behaviour of these mullite precursors was influenced by the presence of impurities in the raw materials. These impurities originate a liquid phase forming a glassy phase which produces a progressive and enhanced densification of the mullite materials by reaction sintering at 1500–1600 °C. The technical properties were also influenced by the relative proportion of vitreous phase. The microstructure of characteristic mullite crystals was revealed by SEM. It was emphasized the use of kaolin waste by-products of mining and sericite clays as valuable raw materials for mullite preparation.

Thermal behaviour of sericite clays as precursors of mullite materials

Thermal analysis of some sericite clays, from several deposits in Spain, which are not exploited at this time, has been studied. The samples have been previously characterized by mineralogical and chemical analysis. Sericite clays have interesting properties, with implications in ceramics and advanced materials, in particular concerning the formation of mullite by heating. According to this investigation by differential thermal and thermogravimetric analysis (DTA-TG), the sericite clay samples can be classified as: Group (I), sericite–kaolinite clays, with high or medium sericite content, characterized by an endothermic DTA peak of dehydroxylation of kaolinite with mass loss, which overlapped with dehydroxylation of sericite, and Group (II), sericite–kaolinite–pyrophyllite clays, with broader endothermic DTA peaks, in which kaolinite is dehydroxylated first and later sericite and pyrophyllite with the main mass loss, appearing the peaks overlapped. X-ray diffraction analysis of the heated sericite clay samples evidenced the decomposition of dehydroxylated sericite and its disappearance at 1050 °C, with formation of mullite, the progressive disappearance of quartz and the formation of amorphous glassy phase. The vitrification temperature is ~ 1250 °C in all these samples, with slight variations in the temperatures of maximum apparent density (2.41–2.52 g mL−1) in the range 1200–1300 °C. The fine-grained sericite content and the presence of some mineralogical components contribute to the formation of mullite and the increase in the glassy phase by heating. Mullite is the only crystalline phase detected at 1400 °C with good crystallinity. SEM revealed the dense network of rod-shaped and elongated needle-like mullite crystals in the thermally treated samples. These characteristics are advantageous when sericite clays are applied as ceramic raw materials.

Arsenate and phosphate removal from water using Fe-sericite composite beads in batch and fixed-bed systems

Abstract Natural sericite clay was modified with iron-oxide and then the modified sericite was encapsulated into beads by employing the ionic gelation method to obtain Fe-sericite composite beads. The materials were fully characterized by N2 adsorption–desorption isotherm, SEM-EDX, XRD, FT-IR and XPS analyses. Batch experiments showed that the composite beads showed a high uptake of As(V) and phosphate within a wide range of pH and the maximum sorption capacity determined by Langmuir isotherm were found to be 5.780 and 4.446 mg/g for As(V) and phosphate, respectively. The sorption kinetic data indicate that at least 12 h of contact time is necessary to attain the sorption equilibrium and intra-particle diffusion plays a significant role in the sorption process. The presence of background electrolyte (NaNO3) or other heavy metals ions could not significantly affect the uptake of As(V)/phosphate by Fe-sericite composite beads. Furthermore, a fixed-bed column experiment has demonstrated that Fe-sericite composite beads could remove As(V) and phosphate up to acceptable level with a high breakthrough volume even under dynamic conditions. XPS analysis results indicate the successful sorption of As(V)/phosphate and it is assumed that these two pollutants formed an inner sphere complexes with iron oxide present in the composite beads.

Effects of Sericite Clay Coating on Controlling the Oxides Scale Formation in the Course of Heat Treatment of 13Cr-Stainless Steel

Effects of Sericite Clay Coating on Controlling the Oxides Scale Formation in the Course of Heat Treatment of 13Cr-Stainless Steel

Geologic features related to formation of the pyrophyllite and sericite clay (roseki) deposits in the Mitsuishi area, Southwest Japan.

Geologic features related to formation of the pyrophyllite and sericite clay (roseki) deposits in the Mitsuishi area, Southwest Japan.

Ammonium-bearing mica and mica/smectite of several pottery stone and pyrophyllite deposits in Japan: their mineralogical properties and utilization

Many pottery stone and pyrophyllite deposits have been developed in southwestern Japan. These deposits are hydrothermal in origin and have produced dioctahedral mica (sericite) minerals usually used for porcelain, tiles, sanitary ware, etc. Sericite specimens from two pottery stone deposits (Izumiyama and Tobe) and three pyrophyllite deposits (Yagi, Mitsuishi and Horo mines) are mineralogically characterized in terms of utilization. These sericite clays are chemically characterized by extensive substitution of NH 4 for K corresponding to the muscovite–tobelite series, resulting in the basal spacing being enlarged from 10.00 Å (muscovite) to 10.36 Å (tobelite), which is diagnostic of the interlayer composition. Infrared absorbance of the NH 4 band (1430 cm −1) standardized to the OH band (3620 cm −1) is also useful for determination of the NH 4 content. DTA of a NH 4-dominant specimen from the Tobe deposit reveals the liberation of NH 4 around 490°C and double steps dehydroxylation in the 600–800°C range, as well as crystallization of mullite and cristobalite at 1000°C. These thermal properties are considered to be effective in sintering and refractoriness of the sericite materials when fired. Most of the sericite specimens are interstratified mica/smectite with <20% smectite, which may be responsible for plasticity when treated in the wet refinement process. Of the sericite clays from the five deposits, the Tobe, Yagi and Mitsuishi specimens are characterized by a varied interlayer NH 4/K ratio, interstratification and lower Fe and Ti content, which favor refractoriness, plasticity and whiteness, respectively: these are excellent qualities for their use as raw materials for porcelain.

Sericite clay as a raw material for the fabrication of whiteware bodies

Abstract The possibility was investigated of abtaining porcelain bodies using a sericitic clay, whose fundamental characteristics are to form a very reactive glassy phase, to have an exceptional firing range and a very fine grain size, and a tendency to produce bodies with a very high mullite content at low temperature. The second aim was to obtain porcelain bodies at low firing temperatures with a high flexural strength and large mullite content using only the above-mentioned clay, alumina and a small and constant amount of feldspar. To cover different porcelain types, both silicious and aluminous, eight compositions were formulated and fired between 1200°C and 1320°C and the technological properties, microstructures, phases, etc., were studied. For comparison with the results obtained with the new compositions, two industrial porcelain bodies were formulated and studied at the same time under the same conditions. The paper shows the possibility of obtaining porcelain bodies with much better properties than present industrial ones, and at the same time with a significant saving in the cost of raw materials.

Geochemical indicators of a high-temperature geothermal system

The intensity and distribution of hydrothermal alteration are frequently used during the exploration and assessment of a geothermal prospect to estimate the size, shape and temperature of a thermal system. Geochemical and petrographic observations used to characterize the hydrothermal alteration include the mapping of both trace- and major-element dispersion patterns and the distribution of secondary mineral assemblages. This paper describes the trace-element and mineralogical distributions common to many of the high-temperature systems (> 150° C) that we have studied. However, examples of important geochemical relationships are primarily drawn from our detailed investigations of the Roosevelt Hot Springs thermal system in southern Utah. The hydrothermal fluids at Roosevelt Hot Springs are enriched in sodium chloride and contain approximately 9000 ppm total dissolved solids. The reservoir, with a base temperature near 270° C, is located in fractured gneisses and granites. At Roosevelt Hot Springs, the surface discharges consist of opaline and chalcedonic sinter, and alluvium cemented by silica, calcite, Mn oxide and Fe oxide. The geochemistry of these surface deposits is extremely variable, but locally they contain up to 5.5 ppm Hg, 858 ppm As, 18.8% Mn, 230 ppm Cu, 290 ppm Sb, 294 ppm W, 17 ppm Li, 68 ppm Pb, 26 ppm Zn, 4.9% Ba and 100 ppm Be. High concentrations of Au and Ag, although not present in the sinters at Roosevelt Hot Springs, occur in hot spring deposits from other chemically similar systems such as Steamboat Springs, Nevada. Mercury and As are the most widely distributed trace elements in the surface samples. Their distribution in soils overlying the thermal system expands the area of interest and helps define the high-temperature portion of the system. The highest concentrations of Hg and As, of up to 5.5 and 26 ppm, respectively, occur in soils within 300 m of the thermal discharges. A broader area extending up to 1000 m from the surficial thermal activity also contains anomalous Hg but with lower concentrations ranging from 50 to 800 ppb. Mercury anomalies tend to mark the location of faults within the uppermost portions of the reservoir and areas where the thermal fluids move laterally away from the thermal system toward the adjacent valley. Depletions of Mn, Cu and Zn are found in the acid-altered soils and in alluvium associated with the hot spring deposits and fumaroles. The acid alteration occurs locally in areas of surficial thermal activity and persists to depths of less than 60 m. Alteration minerals within these zones include alunite, jarosite, native sulphur, opal, chalcedony, kaolinite, sericite, montmorillonite, and mixed-layer clays. The formation of acid waters occurs near the surface and results from the oxidation of H2S contained within gases evolving from the fumaroles or within waters discharged by the hot springs. The locally intense acid-sulphate alteration and scavenging of metals within the soils occurs as the fluids percolate downward. Alteration mineralogy at depth is determined through examination of down-hole samples which penetrate the geothermal system to depths in excess of 2 km. Reservoir rocks of temperatures below about 210°C contain an alteration assemblage with mixed-layer clays, montmorillonite, sericite, pyrite, hematite, magnetite, calcite, chlorite, quartz, and potassium feldspar. At higher temperatures, mixed-layer clays and montmorillonite disappear and anhydrite appears locally. Altered rocks within the high temperature portions of the thermal field are characterized by anomalous concentrations of As and Li. Selective chemical leaching of the altered rocks and electron microprobe analyses indicate that As is contained primarily in pyrite or iron oxides after pyrite whereas Li occurs in clays and micas. Mercury exhibits an inverse relationship with temperature and is concentrated in the cooler portions of the thermal system to depths marked approximately by the 200° C isotherm. This distribution is similar to the distribution of clay minerals in the reservoir rock. Heating experiments indicate that Hg occurs primarily as Hg° and that it is readily mobilized by the thermal system at temperatures in excess of 200–250° C.

Sericite clay as a raw material for the fabrication of whiteware bodies

The possibility was investigated of abtaining porcelain bodies using a sericitic clay, whose fundamental characteristics are to form a very reactive glassy phase, to have an exceptional firing range and a very fine grain size, and a tendency to produce bodies with a very high mullite content at low temperature. The second aim was to obtain porcelain bodies at low firing temperatures with a high flexural strength and large mullite content using only the above-mentioned clay, alumina and a small and constant amount of feldspar. To cover different porcelain types, both silicious and aluminous, eight compositions were formulated and fired between 1200°C and 1320°C and the technological properties, microstructures, phases, etc., were studied. For comparison with the results obtained with the new compositions, two industrial porcelain bodies were formulated and studied at the same time under the same conditions. The paper shows the possibility of obtaining porcelain bodies with much better properties than present industrial ones, and at the same time with a significant saving in the cost of raw materials.

Gypsum deposits of the Katta mine, Miyagi Prefecture

The Katta Mine is mining the bedded type body of gypsum in a Miocene green coloured tuff breccia, that is thought to belong to a type of Black Ore in Japan. The gypsum body consists of massive alabaster, impregnated gypsum and aggregate of spheluritic gypsum of 0.5-2.0cm in diameter. The aggregate occupies the almost all parts of the ore body. A number of gypsum sphelurite have a radiated structure. The occurrence of magnesium chlorite in the high grade gypsum ore is ascertained from the results of X-ray powder diffractions and differential thermal analyses. This mineral is thought to be useful to the ore prospecting.The clay mineral that is universally detected both in an ore body and in its environs is sericite. The writers would like to emphasize that the deposition of gypsum is due to the diffusion of hydrothermal ore solution through a sericite clay which is formed by the pre-ore action and is maintained in a colloidal state.