Статті в журналах: "Pyrophylite"

1

Andrić, Ljubiša, Dragan Radulović, Marko Pavlović, Milan Petrov, and Jovica Stojanović. "Possibility of applying pyrophylite as filler in refractory coatings." Zastita materijala 61, no. 3 (2020): 210–19. http://dx.doi.org/10.5937/zasmat2003210a.

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2

Watanabe, S., T. Ishikura, T. Yamamoto, N. Hayashi, T. Sumi, Y. W. Kim, D. Dyke, and G. Touchard. "The polarity of streaming current in water passing through a pyrophylite disc." Journal of Electrostatics 40-41 (June 1997): 717–21. http://dx.doi.org/10.1016/s0304-3886(97)00121-6.

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3

Arakawa, M., M. Higa, J. Leliwa-Kopystyński, and N. Maeno. "Impact cratering of granular mixture targets made of H2O Ice–CO2 Ice–pyrophylite." Planetary and Space Science 48, no. 15 (December 2000): 1437–46. http://dx.doi.org/10.1016/s0032-0633(00)00088-x.

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4

Honarpazhouh, Jamal, Ali Asghar Hassanipak, and Kumars Seifpanahi Shabani. "Integration of Stream Sediment Geochemical and Aster Data for Porphyry Copper Deposit Exploration in Khatun Abad, North West of Iran / Integracja geochemicznych danych o osadach dennych oraz danych pozyskanych z systemu aster do poszukiwań geologicznych w rejonie złóż miedzi porfirytowej w khatun abad, w północno-zachodniej części iranu." Archives of Mining Sciences 58, no. 1 (March 1, 2013): 37–54. http://dx.doi.org/10.2478/amsc-2013-0003.

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Urumieh-Dokhtar magmatic belt is the host of large porphyry copper deposits in Iran. Khatun Abad area is located in north west part of this belt, so in this study, the stream sediment geochemical survey and hydrothermal alteration zones extracted from ASTER data were used to generation new target for future lithogeochemical survey. In this study after a brief discussion on descriptive statistics, principal component analysis (PCA) and hierarchical cluster analysis were used to compress the information to a few maps and to assist in determining multi-element associations. Then C-A fractal method was used for map classification. In order to extraction hydrothermal zones ASTER data were used. ASTER SWIR bands are most useful for the identification of alteration minerals such as Alunite, Pyrophylite, Kaolinite, Sericute and Carbonates. In this paper based on spectral analysis of ASTER SWIR data six maps of alteration zones were prepared. Geochemical study and spectral analysis of ASTER data showed that mineralization and alteration are limited to E1lb and gr lithological units and have NW-SE trends from east of Khatun Abad to Ghezeljeh-Gheshlaghi.

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5

Lantenois, S., J. M. Beny, F. Muller, and R. Champallier. "Integration of Fe in natural and synthetic Al-pyrophyllites: an infrared spectroscopic study." Clay Minerals 42, no. 1 (March 2007): 129–41. http://dx.doi.org/10.1180/claymin.2007.042.1.09.

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AbstractNumerous studies focus on the relationships between chemical composition and OH-band positions in the infrared (IR) spectra of micaceous minerals. These studies are based on the coexistence, in dioctahedral micas or smectites, of several cationic pairs around the hydroxyl group which each produce a characteristic band in the IR spectrum. The aim of this work is to obtain the wavenumber values of the IR OH vibration bands of the (Al-Fe3+)-OH and (Fe3+-Fe3+)-OH local cationic environments of ‘pyrophyllite type’ in order to prove, disprove or modify a model of dioctahedral phyllosilicate OH-stretching band decomposition. Natural samples are characterized by powder X-ray diffraction (XRD), Fourier transform infrared (FTIR) and Raman spectroscopies and electron microprobe; the hydrothermal synthesis products are also analysed by powder XRD and FTIR after inductively coupled plasma measurements to obtain the chemical compositions of starting gel phases. Natural samples contain some impurities which were eliminated after acid treatment; nevertheless, a small Fe content is found in the pyrophyllite structure. The amount of Fe which is incorporated within the pyrophyllite structure is much more important for the synthetic samples than for the natural ones. The IR OH bands were clearly observed in both natural and synthetic pyrophyllites and assigned to hydroxides bonded to (Al-Al), (Al-Fe) and (Fe-Fe) cationic pairs. During this study, three samples were analysed by DTG to check the cis- or trans-vacant character of the layers and to determine the influence of this structural character on the OH-stretching band position in IR spectroscopy.

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6

Pee, J. H., A. N. Kwak, Jong Young Kim, Yoo Jin Kim, and Kyung Ja Kim. "Effect of Pyrophyllite on the Mullite Generation in Ternary Porcelain System." Key Engineering Materials 512-515 (June 2012): 575–79. http://dx.doi.org/10.4028/www.scientific.net/kem.512-515.575.

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Promoting of mullite generation has been studied by replacing kaolinite with pyrophyllite because of mullite has excellent strength and thermal shock resistance. Effects of promoting of mullite generation and vitrification by replacing kaolinite with pyrophyllite on the mechanical and thermal properties were investigated. Addition of 45-55% pyrophyllite as a replacement of kaolinite (pyrophyllite (45-55%)-feldspar (30%)-clay (20%)) could vitrify samples (water absorption: 0.05%, bulk density: 2.66g/cm3) and improve the strength (122MPa) of samples fired at 1280°C. In ternary porcelain system, pyrophyllite-feldspar-clay, mullite generation of samples with 50% pyrophyllite reaches about 78.7% and thermal expansion coefficient is 5.4×10-6/K. Beyond 50% pyrophyllite addition, quartz and cristobalite phases increased. And thermal expansion coefficient of samples decreased with increasing of mullite amount.

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7

Liu, Bo, Hai Feng Chen, and Pei Song Tang. "The Dynamics for Aqueous Sodium Adsorption and Characterization of Natural Pyrophyllite." Applied Mechanics and Materials 117-119 (October 2011): 1129–32. http://dx.doi.org/10.4028/www.scientific.net/amm.117-119.1129.

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In this experiment, pyrophyllite as the main materials used the flame photometer to measure adsorption. Using the qualitative analysis of the samples of XRD with internal structure and found that pyrophyllite used in the experiment as a natural mineral, the presence with other minerals. Meanwhile, scanning electron micrographs (SEM) from the display showed that the effect of pyrophyllite adsorption for cations should be more significant. Therefore, this experiment focused on the time, Na+ concentration, on the pyrophyllite and different pyrophyllite concentrations (adsorbent dosage) effect on the adsorption, in addition to the adsorption dynamics. The results showed that pyrophyllite adsorption sodium in the best time of equilibrium was 20 minutes, the concentration of NaCl was 50 mg/L, pH = 7, temperature was 313 K, the concentration of pyrophyllite was 5 mg/L.

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8

Park, Jeong-Ann, Jae-Hyun Kim, Chang-Gu Lee, and Song-Bae Kim. "Pyrophyllite clay for bacteriophage MS2 removal in the presence of fluoride." Water Supply 14, no. 3 (December 27, 2013): 485–92. http://dx.doi.org/10.2166/ws.2013.224.

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The aim of this study was to investigate the removal of the bacteriophage MS2 from aqueous solution using pyrophyllite. Batch experiments were conducted to examine MS2 sorption to pyrophyllite. The influence of fluoride, a groundwater contaminant, on the removal of MS2 was also observed. Column experiments were performed with pyrophyllite to examine MS2 removal in the absence and presence of fluoride. Batch results demonstrated that pyrophyllite was effective in MS2 removal. The percentage removal of MS2 increased from 5.26% to 99.99% (4.0 log removal) with increasing pyrophyllite concentrations from 0.2 to 20 g/L. At fluoride concentrations of 5 and 10 mg/L, the log removals of MS2 by pyrophyllite were 3.05 and 2.54, respectively, which were lower than that with no fluoride present. The results suggested that the removal of MS2 by pyrophyllite was influenced by fluoride ions because fluoride ions could compete with MS2 for sorption sites on the pyrophyllite surfaces. Column results showed that pyrophyllite was effective in MS2 removal under flow-through conditions, with a removal capacity of 8.17 × 106pfu/g with no fluoride present and 4.70 × 106pfu/g with 5 mg/L fluoride present.

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9

Mansour, Sabria Malika. "Use of Natural Pyrophyllite as Cement Substitution in Ultra Performance Polypropylene Fiber Concrete." International Journal of Engineering Research in Africa 56 (October 4, 2021): 123–35. http://dx.doi.org/10.4028/www.scientific.net/jera.56.123.

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The present work investigates the use of an alumino-silicate material, the pyrophyllite as cement substitution, synthetic polypropylene fibers and binder to create an unusual ultra-performance fiber concrete; new composite, which offers a wide field of possible use in construction industry. Effect of pyrophyllite on the physical-mechanical properties is analyzed. One reference fiber concrete without pyrophyllite and three fiber concretes containing 10%, 20%, 30% of pyrophyllite were elaborated. Results show that the pyrophyllite affects the characteristics of the concrete. Indeed, in the hardened state, the density of fiber concrete decreased with pyrophyllite rate increasing. Moreover, the use of pyrophyllite slows down the hardening process of concrete, consequently producing at early ages, compressive, flexural and tensile strengths and elastic modulus of concretes approaching without exceeding those of the reference fiber concrete. The fiber concretes are also considered to be of good quality. It seems that the rate of 10 % of pyrophyllite generates the best physical-mechanical performances that approach those of the reference fiber concrete. The use of pyrophyllite as a cement substitution is beneficial since it can help to decrease the production of cement; the amount of CO2 released and protects the environment.

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10

Sheng, Jia Wei, Li Ping Zhang, Jun Yan, Qing Sun, and Jian Zhang. "Nano-Structural Alteration of Pyrophyllite by Grinding Revealed by X-Ray Diffraction and High-Resolution Transmission Electron Microscopy." Journal of Nano Research 40 (March 2016): 72–78. http://dx.doi.org/10.4028/www.scientific.net/jnanor.40.72.

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The mechanical destruction of the pyrophyllite structure and final ground products upon grinding with a laboratory planetary ball mill were investigated using high-resolution transmission electron microscope (HRTEM) coupled with selected area electron diffraction (SAED), field emission scanning electron microscope (SEM) and X-ray diffraction (XRD). Grinding produced a profound structural alteration, resulting in increasing amorphization. Increasing the intensity of grinding resulted in acceleration of the mechanically induced amorphization of the pyrophyllite structure. The pyrophyllite phase was transformed into its anhydride phase during the process of the prolonged grinding. Increasing the grinding intensity resulted in faster destruction of the pyrophyllite structure. The plate-like microcrystal exhibited the 2M-pyrophyllite crystal structure. The pyrophyllite anhydride phase was existed after grinding.

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11

Liu, Hai Tao, Yong Qiang Zhou, Zhen Hong Sheng, Chun Lian Wu, Jing Feng Zhang, Shie Lin, and Xue Jun Weng. "N-(n-butyl)-3-aminopropyltrimethoxysilane-Functional Modified Pyrophyllite: Preparation, Characterisation and Pb(II) Ion Adsorption Property." Advanced Materials Research 79-82 (August 2009): 2075–78. http://dx.doi.org/10.4028/www.scientific.net/amr.79-82.2075.

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The pyrophyllite used in this study was from Taishun County(Wenzhou,China). The surface of pyrophyllite was modified by coating with N-(n-butyl)-3-aminopropyltrimethoxysilane (BAPTS) coupling agent and utility of the BAPTS-modified pyrophyllite was investigated as an adsorbent for removal of Pb(II) ions from aqueous solutions. XRD and SEM analysis were used to characterise the surface modification. It can be clearly observed that the pyrophyllite looses its aculeated surface structure and gains more smooth morphology. It was observed that the BAPTS -modified pyrophyllite adsorbed approximately 94.50% of Pb(II) ions at an initial concentration of 10 mg/l and an amount of BAPTS of 2.0%.

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12

Luo, Zhong Ping. "Research on Removing of Pyrophyllite in Synthetic Diamond by the Physical Method Instead of Chemical Method." Advanced Materials Research 557-559 (July 2012): 1607–11. http://dx.doi.org/10.4028/www.scientific.net/amr.557-559.1607.

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As a harmful impurity, Pyrophyllite must be remove in synthetic diamond purification process. It commonly use chemical method. A trial research is made on the removing of pyrophyllite impurity in synthetic diamond by physical method. As a result, after synthetic diamond materials containing pyrophyllite are selectively interground in the ball grinding machine, the pyrophyllite is effectively broken and removed from the coarse – medium grade diamond only by physical method, but diamond quality is not affected.

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13

Qin, Xinzhan, Jian Zhao, Jiamin Wang, and Manchao He. "Atomic Structure, Electronic and Mechanical Properties of Pyrophyllite under Pressure: A First-Principles Study." Minerals 10, no. 9 (September 1, 2020): 778. http://dx.doi.org/10.3390/min10090778.

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Pyrophyllite is extensively used in the high-pressure synthesis industry as a pressure-transmitting medium because of its outstanding pressure transmission, machinability, and insulation. Therefore, the atomic structure, electronic, and mechanical behavior of pyrophyllite [Al4Si8O20(OH)4] under high pressure should be discussed deeply and systematically. In the present paper, the lattice parameters, bond length, the electronic density of states, band structure, elastic constants, and mechanical parameters of pyrophyllite are investigated using density functional theory (DFT) from a microscopic perspective. The pressure dependence of atomic structure, electronic, and mechanical properties of pyrophyllite is analyzed for a wide range of pressure (from 0 GPa to 13.87 GPa). Under high pressure, the major bond lengths and layer thicknesses decrease slightly, and mechanical properties are improved with increasing pressure. The calculated electronic and band structures show only a slight change with increasing pressure, implying that the effect of pressure on the electronic property of pyrophyllite is weak, and pyrophyllite still has good stability under high pressure. The theoretical calculations presented here clarify the electronic and mechanical properties of natural pyrophyllite that are difficult to obtain experimentally because of their small particle size.

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14

Govedarica-Lučić, Aleksandra, Sanid Pašić, Mirjana Jovović, and Alma Rahimić. "Effects of dose of pyrophyllite on yield and quality of the cabbage." Acta Scientiarum Polonorum Hortorum Cultus 20, no. 5 (October 29, 2021): 25–32. http://dx.doi.org/10.24326/asphc.2021.5.3.

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In this study was researched the influence of the pyrophyllite as a nutrient, bio-stabilizer, soil conditioner, as the adsorbent in different combinations and correlated standard quantitative relations with mineral fertilizers (NPK 15 : 15 : 15), on the yield and nutritional value of Bravo cabbage (Brassica oleraceae var. capitata). Within the examined factor of fertilization treatment, the following variances were represented: a1 – 800 kg ha–1 NPK 15 : 15 : 15 (control plot), a2 – 800 kg ha–1 NPK 15 : 15 : 15 + 2200 kg ha–1 pyrophyllite, a3 – 800 kg ha–1 NPK 15 : 15 : 15 + 1700 kg ha–1 of pyrophyllite, a4 – 800 kg ha–1 NPK 15 : 15 : 15 + 1200 kg ha–1 of pyrophyllite, a5 – 800 kg ha–1 NPK 15 : 15 : 15 + 700 kg ha–1 of pyrophyllite. The purpose of this research was to determine the extent to which the components of the yield and nutritional quality of cabbage depend on the different applied doses of pyrophyllite. The results indicate the fact that the treatments with the application of higher participation of pyrophyllite had a positive effect on the weight and quality of the cabbage head in relation to the control variance.

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15

Wu, Jun Jun, Hai Feng Chen, Shi Jiang Zhao, and Bin Li. "The Impact of Heat Treatment on Pyrophyllite Structure and Acid-Soluble Properties." Advanced Materials Research 366 (October 2011): 326–29. http://dx.doi.org/10.4028/www.scientific.net/amr.366.326.

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This paper studied the influence of heat treatment on the pyrophyllite structure and acid-soluble properties of alumina. Qualitative tests had been performed in studying pyrophyllite crystal at different temperatures by XRD, TG-DTA, FT-IR and quantitative analysis of Al2O3. The quantitative titration method studied the dissolve characteristics of the different heat treatment samples in different acid conditions, and then a numerical simulation was done. The results showed that at temperatures below 480 °C, the pyrophyllite did not change the basic structure. 480~700 °C dehydroxylation reaction occurred, and the structure water of pyrophyllite is removed, and then turned into partial pyrophyllite. Dissolution experiments showed that after thermal activation the behavior of alumina in acid the dissolution was different, which was affected by hydrochloric acid concentration, heat activation temperature and acid leaching time. When the calcinations temperature was 700 °C, the dissolution amount of alumina was largest. These works could provide some theoretical basis for further application of pyrophyllite research.

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16

Adamović, Milan, Mirjana Stojanović, Muhamed Harbinja, Marijana Maslovarić, Aleksandra Bočarov-Stančić, and Lato Pezo. "Efficiency investigation of the use of pyrophyllite in ensiling maize plant." Food and Feed Research 47, no. 2 (2020): 109–18. http://dx.doi.org/10.5937/ffr47-29445.

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The paper presents the results of testing the effect of pyrophyllite shale (pyrophyllite) on the quality of maize plant silage, primarily on the production of organic acids, pH value, quality assessment and microbiological safety. The ensiling was done in plastic containers which allowed the storage of 10 kg of chopped green mass. Tested pyrophyllite doses were: 0% in the control treatment (I), 0.5 and 1.0% in experimental treatments (II and III, respectively). Granulated pyrophyllite (100 µm), originating from Parsovići, Konjic site, AD Harbi Ltd., Sarajevo, Bosnia and Herzegovina, was manually incorporated. The chopped green mass of the maize plant came from FAO 600 hybrids. The green mass containing 37.17% of dry matter (final waxy ripening phase) was compressed in the same manner in all three treatments during the filling of the vessels. The containers were then covered with nylon foil (0.2 mm) above which a layer of fine sand (approx. 5 cm) was placed in toward the silage protection from air passage. The silages were opened after 7 weeks and organoleptic, chemical and microbiological analyses were performed. The organoleptic properties of silages (colour and odour) were better in silages containing 0.5 and 1.0% pyrophyllite. The silage temperature at the moment of opening of the containers was lower in the treatments with 0.5 and 1.0% added pyrophyllite (13.7 and 13.2 °C, respectively) while in the control treatment it was 14.6 °C. The addition of pyrophyllite to silage affected the production of volatile fatty acids (p ≤ 0.05). The highest amount of lactic acid was found in the silage sample without the addition of pyrophyllite, and acetic acid in the silage treated with 0.5 and 1.0% of pyrophyllite. The lowest amount of butyric acid was determined in the silage with the addition of 1% pyrophyllite. Based on the content and interrelationship of lactic, acetic and butyric acid, as well as the pH values, all three silages were rated as the highest (I) class. The number of aerobic mesophilic bacteria, as well as the number of yeasts, was lower in the silages with the addition of 0.5 and 1.0% pyrophyllite. In future, particular attention should be paid on the possibility of pyrophyllite enrichment (e.g. with nitrogen) and more appropriate physical formulation (e.g. granules) that would allow more efficient practical application.

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17

Mansour, Sabria Malika. "Behavior of self- compacting concrete incorporating calcined pyrophyllite as supplementary cementitious material." Journal of Building Materials and Structures 7, no. 1 (October 19, 2020): 119–29. http://dx.doi.org/10.34118/jbms.v7i1.744.

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The current trend of industrial concrete leans more towards the use of self-compacting concrete. These must have fresh properties well defined as fluidity, filling ability and resistance to segregation. However, to ensure the rheological stability, use mineral fines is required. In this work, powder of calcined pyrophyllite (CP) was used as cement substitution at level of 10% and 20% by weight. The interest is focused on the role played by the calcined pyrophyllite to produce SCC with reduced impact environmental.. Calcination of pyrophyllite powder was carried out at 750 °C. Its effect on the workability and mechanical properties of self-compacting concrete is analyzed. The results show that the properties of workability of SCC containing 10% of calcined pyrophyllite tested at fresh state (Slump Flow, T50, passing ability and segregation resistance) are almost identical to those of the control SCC. Furthermore, the calcined pyrophyllite increases the compressive strength, tensile and flexural strength of SCC approaching without exceeding those of the control SCC. It seems that 10 % of calcined pyrophyllite is the optimum replacement rate which improves mechanical strength compared to 20%. Replacing cement with the calcined pyrophyllite aims to save cement and reduce the CO2 emissions released during the manufacture of cement.

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18

Zaykov, V. V., V. N. Udachin, and I. V. Sinyakovskaya. "PYROPHYLLITE DEPOSITS." International Geology Review 30, no. 1 (January 1988): 90–103. http://dx.doi.org/10.1080/00206818809465992.

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19

Ruiz Cruz, M. D., D. Morata, E. Puga, L. Aguirre, and M. Vergara. "Microstructures and interlayering in pyrophyllite from the Coastal Range of central Chile: evidence of a disequilibrium assemblage." Clay Minerals 39, no. 4 (December 2004): 439–52. http://dx.doi.org/10.1180/0009855043940146.

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AbstractPyrophyllite from a Triassic sedimentary formation from the Coastal Range of Chile has been investigated by transmission/analytical electron microscopy (TEM/AEM). The mineral assemblage includes pyrophyllite, muscovite, paragonite, a kaolin mineral, boehmite, rutile and hematite. The textures indicate that the protolith was a volcanoclastic rock. Petrographic evidence, chemistry, and the mineral assemblage suggest the intense leaching of the parent rock by a weathering process, before the metamorphic episode, to create the protolith for the pyrophyllite. Pyrophyllite always grows from the kaolin mineral, and both phases show close orientation relationships. The presence of parallel intergrowths of pyrophyllite and muscovite indicate that muscovite also grew from the kaolin mineral. Nevertheless, the composition of muscovite suggests that this phase must also form from another precursor, probably Al smectite. The AEM data and textural relationships between pyrophyllite and muscovite reveal the presence of two generations of muscovite and suggest that Na-rich muscovite recrystallized into a Na-free muscovite and paragonite.

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20

Ali, Maaz A., Hussin A. M. Ahmed, Haitham M. Ahmed, and Mohammed Hefni. "Pyrophyllite: An Economic Mineral for Different Industrial Applications." Applied Sciences 11, no. 23 (December 1, 2021): 11357. http://dx.doi.org/10.3390/app112311357.

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Pyrophyllite (Al2Si4O10(OH)2) is a phyllosilicate often associated with quartz, mica, kaolinite, epidote, and rutile minerals. In its pure state, pyrophyllite exhibits unique properties such as low thermal and electrical conductivity, high refractive behavior, low expansion coefficient, chemical inertness, and high resistance to corrosion by molten metals and gases. These properties make it desirable in different industries such as refractory; ceramic, fiberglass, and cosmetic industries; as filler in the paper, plastic, paint, and pesticide industries; as soil conditioner in the fertilizer industry; and as a dusting agent in the rubber and roofing industries. Pyrophyllite can also serve as an economical alternative in many industrial applications to different minerals as kaolinite, talc, and feldspar. To increase its market value, pyrophyllite must have high alumina (Al2O3) content, remain free of any impurities, and possess as much whiteness as possible. This paper presented a review of pyrophyllite’s industrial applications, its important exploitable properties, and the specifications required for its use in industry. It also presents the most effective and economical techniques for enriching low-grade pyrophyllite ores to make them suitable for various industrial applications.

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21

Wang, Chi, Qin Zhang, Song Mao, and Shuhao Qin. "Effects of Fine Minerals on Pulp Rheology and the Flotation of Diaspore and Pyrite Mixed Ores." Minerals 10, no. 1 (January 9, 2020): 60. http://dx.doi.org/10.3390/min10010060.

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In this study, the effects of four fine minerals, which were fine diaspore (FDIA), kaolinite, illite, and pyrophyllite (D50 is about 4.55 μm, D80 is about 10.78 μm), on the pulp rheology of the diaspore and pyrite mixed ores (D50 is about 120.53 μm, D80 is about 187.36 μm) and the recovery of pyrite were investigated through flotation tests, pulp rheology measurements, and sedimentation tests. It was found that fine minerals could change the pulp rheology and affect the pyrite recovery. The apparent viscosity of the mixed ores slurry increased with the addition of FDIA, kaolinite, and illite and the pyrite recovery decreased in varying degrees. When the addition was 15 wt.%, the recovery of pyrite decreased from 92.3% to 60.8%, 81.4%, and 84.7%, respectively. The addition of pyrophyllite had a significant deteriorating effect on flotation. When the addition of pyrophyllite was 5 wt.%, the pyrite recovery was reduced to 49.2%, and when the addition was further increased to 15 wt.%, the pyrite recovery reduced to 28.5%. However, the effect of pyrophyllite addition on the pulp rheology of the mixed ore was not remarkable. Pyrophyllite affected pyrite recovery not only by affecting the rheological behavior of the pulp, but also because pyrophyllite was adsorbed on the surface of pyrite and diaspore, producing hetero-aggregation, which made it difficult for the pyrite particles to collide with the bubbles effectively. This was the main reason for the reduction of pyrite recovery. Generally, the order in which the reduction of pyrite recovery was affected by the additions of fine minerals was pyrophyllite > FDIA > kaolinite > illite.

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22

Hung, Khuong The. "Hydrothermal and Metasomatic Kaolin Resource Estimation in the Quang Ninh area, Northeastern Vietnam." Iraqi Geological Journal 54, no. 2E (November 30, 2021): 176–85. http://dx.doi.org/10.46717/igj.54.2e.12ms-2021-11-28.

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In northeastern Vietnam, hydrothermal‐metasomatic kaolinite-pyrophyllite from the secondary quartzite origin has been found in many places, including Pin Ho, Ban Ngai, Khe Khoai, Pec Sec Leng, Tan Mai ore occurrences, etc. They are exploited together with pyrophyllite, alunite, and high‐alumina quartzite as a byproduct. There were 810 chemical and mineral samples in the Quang Ninh area collected to investigate hydrothermal‐metasomatic kaolin resources. The ore minerals consist of kaolin-group minerals (kaolinite, dickite), pyrophyllite, quartz with minor sericite, alunite, diaspora, etc. They were identified by X-ray diffraction, and microscope and scanning electron microscope coupled with energy-dispersive X-ray spectroscopy analyses. Chemical analyses of major oxides were carried out on clays and parent rock samples by X-ray fluorescence spectrometry. The similarity-analogy in ore geology and mineral resource estimation based on statistical methods are employed to estimate hydrothermal‐metasomatic kaolin resources from the Quang Ninh area in northeastern Vietnam. The mineral resource estimation based on statistical methods shows 2.21 million tons of kaolin obtained by the content of aluminum oxide over 28% of the Pec Sec Leng mine, accounting for 14.3% in total. The similarity-analogy in ore geology indicates 158.16 million tons of kaolinite-pyrophyllite ores, of which, 22.0 million tons are kaolin. These methods display that the Quang Ninh area contains mainly pyrophyllite rather than kaolin resources. Our study suggests that the Quang Ninh area can be considered as a potential pyrophyllite resource in northeastern Vietnam for future exploration. Furthermore, the one resource estimation based on similarity-analogy in ore geology method shows an overview of the prospect on kaolinite-pyrophyllite resources in the Quang Ninh area, northeastern Vietnam.

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23

Wu, Jun Jun, Hai Feng Chen, Shi Jiang Zhao, and Bin Li. "Optimization of Conditions for Extraction of Acid-Soluble Al₂O₃ from Pyrophyllite." Advanced Materials Research 366 (October 2011): 330–33. http://dx.doi.org/10.4028/www.scientific.net/amr.366.330.

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Pyrophyllite was the cheap, environmentally friendly alumina silicate clay minerals. This paper studied optimization of conditions for extraction of acid-soluble Al2O3 from pyrophyllite. Qualitative tests had been performed in studying pyrophyllite crystal at different temperatures by using scanning electron microscopy. Dissolution experiments showed that after thermal activation the behavior of alumina in acid the dissolution was different, which was affected by hydrochloric acid concentration, heat activation temperature and acid leaching time. When the calcinations temperature was 700 °C and hydrochloric acid concentration was 25%, the dissolution amount of alumina largest. The fit results indicated that the research for the relationship between dissolution and time by Using Exponential function series Asymptotic1 model to fitting match was the best. So the above function could be used to estimate each time the dissolution of alumina from pyrophyllite in hydrochloric acid.

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24

MUKHAMEDZYANOVA, A. A., U. Sh SHAYAKHMETOV, N. Kh AZAUGILDINA, and I. A. IKHSANOV. "CHANGES IN THE PHYSICAL AND CHEMICAL PROPERTIES OF NANOCERAMIC COMPOSITIONS BASED ON PYROPHYLLITE-CONTAINING RAW MATERIALS." Fundamental and Applied Problems of Engineering and Technology, no. 4 (2021): 124–30. http://dx.doi.org/10.33979/2073-7408-2021-348-4-124-130.

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The use of the pyrophyllite mineral in the production of ceramics and refractories is determined by a number of valuable technological properties: good machinability, high chemical resistance, low content of alkali metal oxides and coloring oxides, use as a thinning additive, etc. The results of a study of physico-chemical processes occurring when heating compositions based on pyrophyllite-containing raw materials by various instrumental methods are presented. The temperatures of dehydration of diaspore, sericite and kaolinite, the formation of mullite from kaolinite and the transition of γ→α-aluminum oxide are determined. The temperatures of the beginning of deformation of ceramic compositions based on pyrophyllite-containing raw materials were determined when the samples were heated to 750°C and 1300°C. The coefficient of expansion of a ceramic material based on pyrophyllite-containing raw materials is calculated. As a result, an annealing-free technology of thin-walled reinforced tubular products using a phosphate binder was created.

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25

Chen, Hai Feng, Pei Song Tang, Min Hong Xu, and Feng Cao. "Isotherms for Aqueous Potassium Adsorption and Characterization of Natural Pyrophyllite." Materials Science Forum 694 (July 2011): 682–85. http://dx.doi.org/10.4028/www.scientific.net/msf.694.682.

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The present investigatory founded an effectiveness of inexpensive and eco-friendly alumina silicate clay minerals, sericitic pyrophyllite (SP), as an adsorbent for the possible application in the absorption of K+. The crystal structure of pyrophyllite, size and morphology were characterized by XRD and SEM. In addition to pyrophyllite, quartz and were also contained in the minerals. The area of lamellar SP was about dozens um2. The results showed that potassium was absorbed on the SP under different pH and concentrations, and the best condition was pH=6, the time of equilibrium absorption = 30 min. It has been found that these natural minerals are effective in removing 55−75% of K+ from 5.0 to 20 mgL-1 KNO3 solutions. The applicability of the Langmuir, Freundlich and Dubinin-Radushkevich adsorption isotherms in each case of potassium was examined separately. We found that the adsorption process was endothermic in the case of SP and the Freundlich adsorption model was to more suitably represent the data. The work could provide the theoretical basis of the study of potassium ions adsorbed by pyrophyllite applying in fertilizer.

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26

Murtić, Senad, Emina Sijahović, Hamdija Čivić, Mirza Tvica, and Josip Jurković. "In situ immobilisation of heavy metals in soils using natural clay minerals." Plant, Soil and Environment 66, No. 12 (December 2, 2020): 632–38. http://dx.doi.org/10.17221/371/2020-pse.

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This study attempted to evaluate the efficiency of zeolite and pyrophyllite ore materials in reducing the mobility of heavy metals in soil near the lignite mining dumps, and consequently in their availability for plants. Extraction of pseudo-total and available forms of heavy metals from soil samples was performed by using aqua regia and ethylenediaminetetraacetic acid, respectively. Concentrations of heavy metals in soil and plant samples were determined by atomic absorption spectrophotometry. The results of this study illustrate that application of zeolite and pyrophyllite could be a suitable technique to reduce heavy metals availability in soils. Zeolite treatments have been shown to be significantly effective in reducing cadmium (Cd) mobility, as well as pyrophyllite treatments in reducing lead (Pb) mobility in the studied soil, regardless of applied rates. The accumulation of heavy metals in leaves of maize grown on soil plots treated by zeolite and pyrophyllite, was found to be lower compared to the untreated plots. This finding was to be expected, considering the effects of these treatments on heavy metals mobility in the studied soil.

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27

Meechoowas, Ekarat, Kanit Tapasa, and Tepiwan Jitwatcharakomol. "Alternative Soda-Lime Glass Batch to Reduce Energy Consumption." Key Engineering Materials 545 (March 2013): 24–30. http://dx.doi.org/10.4028/www.scientific.net/kem.545.24.

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Soda-lime glass is produced by melting sand (SiO2), soda ash (Na2CO3), lime stone (CaCO3) together with effective additives such as dolomite (CaMg(CO3)2) and an important structural modification, alumina (Al2O3) in which the melting temperature is very high around 1500°C. With this reason, to dissolve alumina, high amount of energy is needed. Consequently, one of possibilities to reduce the melting energy is replacing alumina by the raw material with a lower enthalpy of melting. The heat required for melting the batch of raw materials from atmosphere temperature to melting temperature is called exploited heat (Hex), which can be calculated from chemical enthalpy (H°chem) and heat content (Hmelt) at reference temperature (Tex). From thermodynamic approach, chemical enthalpy of alumina is higher than feldspar (KAlSiO3) or pyrophyllite (Al2Si4O10(OH)2). For the glass batch with alumina, the calculated exploited heat is 540 kWh/ton while the batch with feldspar or pyrophyllite is lower, namely 534 and 484 kWh/ton, respectively. This means that the melting process can be emerged easier than the batch with alumina because the melting point of feldspar is around 1200°C and pyrophyllite dehydroxylates around 900°C. The kinetic properties of batch melting were investigated by Batch-Free Time method, which defines the melting ability of the modified batch. According to thermodynamic calculation, it was found that both alternative batches were melted easier. The study showed that feldspar or pyrophyllite could be used instead of alumina without significant changes in glass chemical composition and physical properties. The concern of using feldspar or pyrophyllite is the quantity of minor impurities which affect to the color appearance especially in clear glass products.

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28

Bocarov-Stancic, Aleksandra, Jelena Krulj, Marijana Maslovaric, Marija Bodroza-Solarov, Rade Jovanovic, Radmila Beskorovajni, and Milan Adamovic. "Antimicrobial activities of different agents including pyrophyllite against foodborne pathogens: A brief review." Acta Periodica Technologica, no. 52 (2021): 189–201. http://dx.doi.org/10.2298/apt2152189b.

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There has been worldwide an increasing interest and more strict criteria for food/feed safety including absence or reduction of the total number of microorganisms (bacteria, moulds and yeasts). Besides heavy metals, materials of biological origin (plant extracts, bio waste, chitosan etc.), some mineral adsorbents also have antimicrobial properties. There is much information about the antibacterial activity of the modified bentonite, montmoriollonite, smectute, zeolites and antifungal activity of various metal ion-exchanged zeolites and natural mineral clay, but there is almost no information about the antimicrobial properties of pyrophyllite, a monoclinic mineral from the group of phyllosilicates. This work summarizes the recent developments of antimicrobial agents and their application, current research, and trends in the area, highlighting pyrophyllite and its potential applications. Pyrophyllite, an unexploited mineral, possesses antimicrobial properties such as antibacterial and antifungal activities against foodborne pathogens which contributes to the protection of consumer?s health and preservation of the environment. Results from preliminary investigations indicate that pyrophyllite showed antibacterial properties against Escherichia coli, Staphylococcus aureus, Enterococcus faecalis, and antifungal properties against fungal pathogens (Fusarium oxysporum, Phoma glomerata and Rhizoctonia solani). This mineral can also be used for biological control of F. oxysporum in the soil for growing potato.

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29

Gonzlez Lopez, J. M., I. Subias Pirez, C. Fernandez-Nieto, and I. Fanlo Gonzalez. "Lithium-Bearing Hydrothermal Alteration Phyllosilicates Related to Portalet Fluorite Ore (Pyrenees, Huesca, Spain)." Clay Minerals 28, no. 2 (June 1993): 275–83. http://dx.doi.org/10.1180/claymin.1993.028.2.08.

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AbstractPhyllosilicate associations in hydrothermally altered fluorite ore bodies are: Li-chlorite ± pyrophyllite ± interstratified minerals ± muscovite +± kaolinite. Chlorites, the main alteration minerals, are dioctahedral, d060 = 1.489-1-490/~,, of Ia polytype. The structural formulae indicate substitution of AI for Si from 0.61-0.78 atoms. The total octahedral occupancy ranges from 4.52-4-71 atoms, with 0.49-0-69 Li atoms per half cell unit. This composition indicates that the chlorites are intermediate members of the donbassite-cookeite series proposed by Sudo (1978). The mineralogical associations and textural relations suggest that after intensive silicification which produced alkali alteration under acid conditions, pyrophyllite was produced at the expense of muscovite and then Li-bearing donbassite formed from the pyrophyllite. The Li needed for the formation of the chlorites could be genetically related to granitic batholiths which occur close to the fluorite ores.

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30

Sakuma, Hiroshi, Kenji Kawai, and Toshihiro Kogure. "Interlayer energy of pyrophyllite: Implications for macroscopic friction." American Mineralogist 105, no. 8 (August 1, 2020): 1204–11. http://dx.doi.org/10.2138/am-2020-7333.

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Abstract Deformation of phyllosilicate can control the dynamics of the Earth's crust. The phenomenological relationship between stress and deformation is known for some typical phyllosilicates; however, the underlying physics originating from the crystal structures is poorly understood. In this study, the deformation mechanism of pyrophyllite along basal planes was revealed through density functional theory calculations and atomic-scale theory of friction. The stable and metastable interlayer structures formed by interlayer slide were consistent with the experimental results reported previously by high-resolution transmission electron microscopy. The difference in potential energies between stable and metastable interlayer structures can be interpreted as the difference in the stacking of dioctahedral sheets between the adjacent layers. The estimated friction coefficient of the pyrophyllite between adjacent layers was consistent with the results of atomic force microscopy, suggesting that atomic-scale friction can be adequately estimated by this method. The calculated shear stress in our simulations has a linear relationship with the normal stress and has no significant crystallographic dependence on sliding direction along the basal planes. The crystallographic isotropy of interlayer friction is explained by the absence of interlayer cations in pyrophyllite, while muscovite showed crystallographic anisotropy as observed in previous studies. The macroscopic friction of a single crystal of pyrophyllite was estimated from atomic-scale friction by using the area of contact. The macroscopic friction coefficient of ideal interlayer sliding was estimated to be 0.134, which was smaller than a reported value (0.276) in shear experiments conducted for wet polycrystalline gouge layers. This difference can be primarily explained by the degree of orientation of pyrophyllite particles in the gouge layers. The friction coefficient estimated by a simple model of randomly oriented pyrophyllite gouge layer was 0.203 ± 0.001, which was similar to the reported value of 0.276 and clearly smaller than the values (0.6–0.85) of common minerals estimated by the empirical Byerlee's law. These results indicate that weak interlayer friction of phyllosilicates has a large effect on the low frictional strength of gouge layers in natural faults. Our methodology and results are useful for understanding the physics behind the phenomenological friction laws of phyllosilicate gouge.

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31

Braithwaite, R. S. W. "Kegelite: infrared spectroscopy and a structural hypothesis." Mineralogical Magazine 55, no. 378 (March 1991): 127–34. http://dx.doi.org/10.1180/minmag.1991.055.378.11.

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AbstractThe infrared spectrum of kegelite has been measured and is discussed. The infrared spectra of 1 : 1 molar mixtures of leadhillite with pyrophyllite or with muscovite resemble the spectrum of kegelite, the chemical formula of which is a 1 : 1 stoichiometric sum of those of pyrophyllite and of the leadhillite polymorphs. Kegelite is not a physical mixture of these species, but its structure may be an interlayering of phyllosilicate and leadhillite-like structures within the unit cell. The unit cell parameters of pyrophyllite-1Tc and the leadhillite polymorphs are compatible with each other and can be combined to give a cell with parameters close to those of the kegelite cell. A structural model for kegelite on these bases is suggested, which is also consistent with its thermal analysis. The formula of kegelite can be written as Pb8(SO4)2(CO3)4(OH)4(AlOH)4(Si4O10)2.

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32

Zaykov, V. V., and V. N. Udachin. "Pyrophyllite and pyrophyllite raw materials in the sulfide-bearing areas of the Urals." Applied Clay Science 8, no. 6 (February 1994): 417–35. http://dx.doi.org/10.1016/0169-1317(94)90037-x.

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33

Dryzek, Jerzy, Ewa Dryzek, and Piotr Golonka. "Positron annihilation studies in pyrophyllite." Journal of Physics: Condensed Matter 14, no. 50 (December 13, 2002): 13857–66. http://dx.doi.org/10.1088/0953-8984/14/50/311.

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34

Rodriguez, J. L. Pérez. "Pyrophyllite Determination in Mineral Mixtures." Clays and Clay Minerals 33, no. 6 (1985): 563–66. http://dx.doi.org/10.1346/ccmn.1985.0330614.

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35

Sanchez-Soto, P. J., and J. L. Perez-Rodriguez. "Thermal analysis of pyrophyllite transformations." Thermochimica Acta 138, no. 2 (February 1989): 267–76. http://dx.doi.org/10.1016/0040-6031(89)87263-6.

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36

PEREZMAQUEDA, L. "Thermal transformations of sonicated pyrophyllite." Applied Clay Science 24, no. 3-4 (February 2004): 201–7. http://dx.doi.org/10.1016/j.clay.2003.03.003.

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37

Guggenheim, S., J. M. Adams, F. Bergaya, M. F. Brigatti, V. A. Drits, M. L. L. Formoso, E. Galán, T. Kogure, H. Stanjek, and J. W. Stucki. "Nomenclature for stacking in phyllosilicates: Report of the Association Internationale pour l'Etude des Argiles (AIPEA) Nomenclature Committee for 2008." Clay Minerals 44, no. 1 (March 2009): 157–59. http://dx.doi.org/10.1180/claymin.2009.044.1.157.

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Kogure and co-workers have published several papers reporting the stacking structures of various 2:1 layer phyllosilicates (e.g. aspidolite, Kogure et al. (2004); wonesite, Kogure et al. (2005); pyrophyllite, Kogure et al. (2006)), mainly by using high-resolution transmission electron microscopy (HR-TEM). However, there is ambiguity in wording that refers to the lateral displacement between two tetrahedral sheets across the interlayer regions. Zvyagin et al. (1969) used the symbol “τ” for this displacement, which describes the structures of pyrophyllite and talc, but no universally accepted wording was used for other 2:1 phyllosilicates or 1:1 phyllosilicates.

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38

Šajgalík, Pavol, J. Křest'an та Zoltán Lenčéš. "Corrosion Resistance of β-SiAlON-Based Ceramics Against Molten Steel". Materials Science Forum 554 (серпень 2007): 147–50. http://dx.doi.org/10.4028/www.scientific.net/msf.554.147.

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The corrosion resistance of sialons made from commercial powders (AlN, Al2O3 and Si3N4) and from powder precursor produced by carbothermal reduction and nitridation of raw aluminosilicate (pyrophyllite) in molten steel were investigated. The corroded zone in sialon made from raw pyrophyllite (P1) is more then two times deeper compared to the corroded zone of sialon made from commercial powders (C1). The corrosion zone of sample P1 is on the average 610 μm deep, while in sample C1 it is only 260 μm. The main corrosion products are γ-Al2O3 and iron silicides. The phase compositions were estimated by neutron Rietveld refinement.

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39

Fang, Shuai, Zhenghao Cai, Yongkui Wang, Zhiyun Lu, Chao Fang, Zhandong Zhao, Hongan Ma, Liangchao Chen, and Xiaopeng Jia. "Growth and characterization of diamond single crystals grown in the Fe–S–C system by the temperature gradient method." CrystEngComm 23, no. 10 (2021): 2063–70. http://dx.doi.org/10.1039/d0ce01548b.

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40

Pérez-Rodríguez, J. L., L. Madrid Sánchez del Villar, and P. J. Sánchez-Soto. "Effects of dry grinding on pyrophyllite." Clay Minerals 23, no. 4 (December 1988): 399–410. http://dx.doi.org/10.1180/claymin.1988.023.4.07.

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AbstractDry grinding of pyrophyllite (Hillsboro, USA) has been studied by X-ray diffraction (XRD), specific surface area measurements (BET) and scanning electron microscopy (SEM). At the beginning of the grinding process, some effects such as delamination, gliding and folding of the layers, and decrease in particle size were detected by SEM and XRD, resulting in a large increase in specific surface area, up to a maximum of ∼60 m2·g−1. Marked changes in the structure take place between 30 and 32 mins grinding. Longer grinding times increase the degree of disorder and SEM and specific surface area data suggest that aggregation occurs. XRD results indicate that some residual order persists in the degraded structure.

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41

Sinyakovskaya, Irina, Victor Zaykov, and Ryuji Kitagawa. "Types of Pyrophyllite Deposits in Foldbelts." Resource Geology 55, no. 4 (December 2005): 405–18. http://dx.doi.org/10.1111/j.1751-3928.2005.tb00261.x.

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42

Moon, Dong Hyeok, Kyeong Yoon Kwak, Bu Yeong Lee, Hyo Jin Koo, and Hyen Goo Cho. "Hydrothermal Alteration of Miryang Pyrophyllite Deposit." Journal of the mineralogical society of korea 28, no. 3 (September 30, 2015): 265–77. http://dx.doi.org/10.9727/jmsk.2015.28.3.265.

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43

Bryndzia, L. Taras. "The origin of diaspore and pyrophyllite in the Foxtrap pyrophyllite deposit, Avalon Peninsula, Newfoundland; a reinterpretation." Economic Geology 83, no. 2 (April 1, 1988): 450–53. http://dx.doi.org/10.2113/gsecongeo.83.2.450.

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44

Komadel, P., J. Bujdák, J. Madejová, V. Šucha, and F. Elsass. "Effect of non-swelling layers on the dissolution of reduced-charge montmorillonite in hydrochloric acid." Clay Minerals 31, no. 3 (September 1996): 333–45. http://dx.doi.org/10.1180/claymin.1996.031.3.04.

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AbstractA series of reduced-charge montmorillonites (RCM), prepared from the same parent Li-montmorillonite (Jelšový Potok, Slovakia) by heating at various temperatures (105–210°C) for 24 h, was treated with 6 m HCl at 95°C for periods up to 30 h. Reaction solutions obtained were analysed for Al, Fe, Mg and Li and the solid reaction products were investigated by FTIR spectroscopy. Both analyses provided evidence that the extent of dissolution decreased with increased amounts of Li fixed within the montmorillonite structure, i.e. with increased heating temperature. Differences in the acid dissolution process were reflected in the structural changes which occurred within the RCM samples, due presumably to different positions of fixed Li. The ethylene glycol monoethyl ether (EGME) surface areas, and XRD and HRTEM analyses of the RCM series revealed an increased amount of non-swelling layers in the samples prepared at higher temperatures, which caused a substantially slower decomposition of M7 and M8 in HCl. The calculated XRD patterns of M6 and M7 confirmed the presence of 20% and 45% pyrophyllite-like layers, respectively, in these samples. Mixed-layer pyrophyllite-like-smectite and pyrophyllite-like crystals, containing only non-swelling layers, were found in sample M8. The results confirmed that the amount of swelling layers in RCM significantly affects their dissolution rate in HCl.

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45

Sánchez Soto, P. J., M. C. Jiménez de Haro, J. Pascual Cosp, M. Raigón Pichardo, and J. L. Pérez Rodríguez. "Influencia de los tratamientos mecánicos y térmicos en materias primas que contienen pirofilita." Boletín de la Sociedad Española de Cerámica y Vidrio 39, no. 1 (February 28, 2000): 119–34. http://dx.doi.org/10.3989/cyv.2000.v39.i1.881.

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46

Dong, H., D. R. Peacor, R. J. Merriman, and S. J. Kemp. "Brinrobertsite: a new R1 interstratified pyrophyllite/smectite-like clay mineral: characterization and geological origin." Mineralogical Magazine 66, no. 4 (August 2002): 605–17. http://dx.doi.org/10.1180/0026461026640045.

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AbstractBrinrobertsite, an ordered, mixed-layered, dioctahedral pyrophyllite-smectite (P/S), occurs in a metabentonite in the Ordovician Nant Ffrancon Formation near Bangor, N Wales. It comprises ~30% of the metabentonite, in association with quartz (~50%) and chlorite (clinochlore; 20%) which replaced glass shards and fine-grained glass matrix. Transmission electron microscopy (TEM) images show sequences of dominant ~24 Å 001 lattice fringes inferred to correspond to 2:1 layers with alternate pyrophyllite-like (low-charge) and smectite-like (higher-charge) interlayers (i.e. R1 ordering). The hk0 diffraction patterns are mostly hexanets with some spotty circles, implying that layers are largely coherently related, but with some turbostratic stacking. Collective data show that d100 = 5.2, b = 9.1, and d001 = 24–25 Å, assuming monoclinic or pseudomonoclinic symmetry. The composition, as determined by energy dispersive spectral analysis, is (Na0.22K0.07Ca0.06)(Al3.81Mg0.08Fe0.08)(Si7.84 Al0.16)O20(OH)4·3.54H2O, as consistent with the sum of the compositions of pyrophyllite-like and smectite-like units. Water content was determined by DTA/TGA analysis. The powder diffraction patterns have a principal peak with d001 = 24.4 Å. Patterns of air-dried and glycol-saturated brinrobertsite, including Na- and Ca-saturated and untreated samples, were modelled satisfactorily as R1-ordered P/S by the program NEWMOD-for-Windows. The unique composition of brinrobertsite relative to R1 IS, which is ubiquitous in metabentonites, was caused by leaching of alkalis and alkaline-earth elements by hydrothermal fluids associated perhaps with a nearby intrusion, as demonstrated by bulk-chemical analyses of the metabentonite. The crystal structure is modelled as having Al/Si distributions symmetrical by reflection across interlayers. This causes all 2:1 layers to be equivalent in having one tetrahedral sheet with little or no Al, and the other with significant Al substitution, giving rise to alternate high- and low-charge interlayers. Geological evidence suggests that brinrobertsite is a back-reacted product of hydrothermal alteration in the sequence: glass → pyrophyllite → brinrobertsite.

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47

Schomburg, Joachim. "Thermal investigations of pyrophyllites." Thermochimica Acta 93 (September 1985): 521–24. http://dx.doi.org/10.1016/0040-6031(85)85131-5.

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48

Luna, Carla Romina, Walter Guillermo Reimers, Marcelo Javier Avena, and Alfredo Juan. "Theoretical study of the octahedral substitution effect in delaminated pyrophyllite: physicochemical properties and applications." Physical Chemistry Chemical Physics 23, no. 27 (2021): 14601–7. http://dx.doi.org/10.1039/d1cp01032h.

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Fe²⁺ and Fe³⁺ substitutions induce a paramagnetic behavior and a non-zero magnetic moment appears. Then, new applications could be expected with respect to pyrophyllite and montmorillonite.

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49

Meechoowas, Ekarat, Konnika Tui-Ai, Kanit Tapasa, Usuma Naknikham, and Tepiwan Jitwatcharakomol. "Increasing the Melting Ability of Glass Batch by Batch Modification." Advanced Materials Research 770 (September 2013): 128–31. http://dx.doi.org/10.4028/www.scientific.net/amr.770.128.

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The soda-lime glass with the composition of 74SiO2-18Na2O-6CaO-B2O3-Al2O3 thermodynamically requires the exploited heat of 557 kW/ ton of glass to transform raw materials into glass. The objective of this project is to modify the soda-lime glass batch by using wollastonite instead of limestone and pyrophyllite instead of aluminium hydroxide. The exploited heat of the batch with wollastonite is reduced to 546 kW/ton of glass while the batch with wollastonite and pyrophyllite is decreased to 550 kW/ton of glass. According to Batch-Free Time testing, it is found that the melting ability of both modified batches is higher than of the original batch, while the properties of glass are slightly changed. This implies that the modified batch requires a lower melting energy than the original batch.

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50

Alcover, J. F., and R. F. Giese. "Energie de liaison des feuillets de talc, pyrophyllite, muscovite et phlogopite." Clay Minerals 21, no. 2 (June 1986): 159–69. http://dx.doi.org/10.1180/claymin.1986.021.2.05.

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ResumeNous présentons une méthode de calcul de l'énergie totale d'une structure cristallińe (énergie électrostatique, énergie de van der Waals, et énergie de répulsion). Nous utilisons ensuite cette méthode pour étudier une série de phyllosilicates (talc, pyrophyllite, muscovite et phlogopite), pour comparer et discuter leurs propriétés physico-chimiques en particulier l'énergi de liaison interfoliaire et la distance interlamellaire. Nous constatons que des méthodes de calcul, basées sur des expressions empiriques différentes de l'énergie de répulsion, conduisent à des résultats relatifs analogues. Nous vérifions que la distance interlamellaire calculée approche la distance mesurée à 0·1 Å près. Nous calculons des énergies de liaison interfoliaire du talc et de la pyrophyllite (de l'ordre de 30 Kcal/mol) plus faibles que celles de la muscovite et de la phlogopite (de l'ordre de 60 Kcal/mol).

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