Structural Evolution of Natural Flake Graphite with Different Particle Sizes during the Intercalation and Exfoliation Processes

2011 ◽  
Vol 80-81 ◽  
pp. 221-224
Author(s):  
Xue Qing Yue ◽  
Yan Lu ◽  
Dong Hua Lu

In order to investigate the structural evolution of natural flake graphite with different particle sizes during the intercalation and exfoliation process, we used three natural graphites, 35, 50 and 80 mesh, as the raw material and investigated the characteristics of the three chemically prepared graphite intercalation compounds (GICs) of H2SO4 and the three corresponding residue GICs (RGICs). Expanded graphites (EGs) were prepared by rapidly heating the RGICs to 1000 °C in a muffle. The Results show that with decreasing the raw graphite particle size, the oxidizing reaction degree of GIC increases, but the intercalating reaction degree decreases. For RGICs, the relative ratio of RGIC phase in a sample decreases with decreasing the raw material particle size. In addition, decreasing the raw graphite particle size decreases the expanded volume of EG.

2010 ◽  
Vol 163-167 ◽  
pp. 2333-2336 ◽  
Author(s):  
Kun Yu

Three natural graphite flakes (35, 50 and 80 mesh) were used as raw material. Exfoliated graphite (EG) was prepared by rapidly heating residue H2SO4-graphite intercalation compounds (RGIC) in a muffle and by irradiating it in a microwave oven, respectively. Results show that the exfoliation volume of EG decreases with decreasing the raw graphite particle size. Compared with muffle heating, microwave irradiation is more helpful for the exfoliation of RGICs, especially for the small particle samples.


Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1061
Author(s):  
Honggang Chen ◽  
Mingzhong Wang ◽  
Yao Qi ◽  
Yongbo Li ◽  
Xiaopeng Zhao

A smart meta-superconductor Bi(Pb)SrCaCuO (B(P)SCCO) may increase the critical transition temperature (TC) of B(P)SCCO by electroluminescence (EL) energy injection of inhomogeneous phases. However, the increase amplitude ΔTC (ΔTC=TC−TC,pure) of TC is relatively small. In this study, a smart meta-superconductor B(P)SCCO with different matrix sizes was designed. Three kinds of raw materials with different particle sizes were used, and different series of Y2O3:Sm3+, Y2O3, Y2O3:Eu3+, and Y2O3:Eu3++Ag-doped samples and pure B(P)SCCO were prepared. Results indicated that the TC of the Y2O3 or Y2O3:Sm3+ non-luminescent dopant doping sample is lower than that of pure B(P)SCCO. However, the TC of the Y2O3:Eu3++Ag or Y2O3:Eu3+ luminescent inhomogeneous phase doping sample is higher than that of pure B(P)SCCO. With the decrease of the raw material particle size from 30 to 5 μm, the particle size of the B(P)SCCO superconducting matrix in the prepared samples decreases, and the doping content of the Y2O3:Eu3++Ag or Y2O3:Eu3+ increases from 0.2% to 0.4%. Meanwhile, the increase of the inhomogeneous phase content enhances the ΔTC. When the particle size of raw material is 5 μm, the doping concentration of the luminescent inhomogeneous phase can be increased to 0.4%. At this time, the zero-resistance temperature and onset transition temperature of the Y2O3:Eu3++Ag doped sample are 4 and 6.3 K higher than those of pure B(P)SCCO, respectively.


Carbon ◽  
2006 ◽  
Vol 44 (12) ◽  
pp. 2590-2592 ◽  
Author(s):  
F. Vieira ◽  
I. Cisneros ◽  
N.G. Rosa ◽  
G.M. Trindade ◽  
N.D.S. Mohallem

2020 ◽  
Vol 1012 ◽  
pp. 233-238
Author(s):  
Vanessa Moura de Souza ◽  
Vinícius Martins ◽  
Rejane Maria Candiota Tubino

This paper evaluated the use of the pitcher, a ceramic waste obtained through the quality process of a sanitary ware industry, in the development of a material for usage in the manufacture of sintered parts. The pitcher was obtained through powder technology and is composed, according to the chemical analysis obtained by X-ray fluorescence spectrometry, of clayey minerals (clay and kaolin), quartz, and feldspar, which may include ceramic rocks such as granite, pegmatite and phyllite; that is, it has proved to be a potential raw material due to the minerals that can still be reused. The pitcher passed through a granulometry-based selection process, sieving about 20kg using the following sieve sequence: 18 MESH, 25 MESH, 30 MESH, 120 MESH and 400 MESH; with around 70% of the residue being retained in the sieves of 120 and 400 MESH, which were selected to be used in the evaluation. The samples were compacted in a manual press with different pressures, between 300 and 1000 kgf, and after were sintered at a temperature of 1100oC in a resistive furnace. To characterize the material, the apparent and green density, as well as the compressibility curve, were determined to identify the best compression pressure. The microstructure of the test specimen and the pitcher homogeneity were evaluated using Scanning Electron Microscopy (SEM). Both particle sizes presented the typical compressibility curve, in which the density increases with increasing compaction pressure, while the curve slope decreases with increasing pressure. The density increase with the increasing compaction pressure indicates a good densification for the temperatures, independent of the sample granulometry. The sintering porosity decreased proportionally to the particle size in the sintered samples. The analysis showed that the particle size of 400 MESH sintered at 1100oC obtained more porous surfaces, thus indicating a promising future for the manufacture of parts using powder technology, especially for the development of filters.


1988 ◽  
Vol 37 (11) ◽  
pp. 607-611
Author(s):  
Kazumi MIZUKAMI ◽  
Shigeo KASAI ◽  
Naoki KASAI ◽  
Kazuhiko AMAKAWA

2009 ◽  
Vol 33 (6) ◽  
pp. 1855-1862 ◽  
Author(s):  
Valdeci Orioli Júnior ◽  
Edson Luiz Mendes Coutinho

The current high price of KCl and great dependence on importation to satisfy the Brazilian demand indicate the need for studies that evaluate the efficiency of other K sources, particularly those based on domestic raw material. For this purpose, a greenhouse experiment was conducted with samples of a sandy clay loam Typic Haplustox, in a completely randomized 4 x 3 x 2 factorial design: four K rates (0, 60, 120, and 180 mg kg-1), three sources (potassium chloride (KCl), fused magnesium potassium phosphate (FMPP) and a mixture of 70 % FMPP + 30 % KCl) and two particle sizes (100 and 60 mesh), with three replications. Potassium fertilization resulted in significant increases in shoot dry matter production and in K concentrations, both in soil and plants. The K source and particle size had no significant effect on the evaluated characteristics. Potassium critical levels in the soil and the shoots were 1.53 mmol c dm-3 and 19.1 g kg-1, respectively.


Polymers ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1361
Author(s):  
Maria Teresa Ferrandez-García ◽  
Antonio Ferrandez-Garcia ◽  
Teresa Garcia-Ortuño ◽  
Clara Eugenia Ferrandez-Garcia ◽  
Manuel Ferrandez-Villena

Traditionally, plant fibres have been used as a raw material for manufacturing construction materials; however, in the last century, they have been replaced by new mineral and synthetic materials with manufacturing processes that consume a large amount of energy. The objective of this study was to determine the mechanical, physical and acoustic properties of panels made from giant reed residues. The article focuses on evaluating the acoustic absorption of the boards for use in buildings. The materials used were reed particles and urea–formaldehyde was used as an adhesive. The panels were produced with three particle sizes and the influence that this parameter had on the properties of the board was evaluated. To determine the absorption coefficient, samples were tested at frequencies ranging from 50 to 6300 Hz. The results showed that the boards had a medium absorption coefficient for the low and high frequency range, with significant differences depending on the particle size. The boards with 2–4 mm particles could be classified as Class D sound absorbers, while boards with particle sizes of 0.25–1 mm showed the greatest sound transmission loss. Unlike the acoustic properties, the smaller the particle size used, the better the mechanical properties of the boards. The results showed that this may be an appropriate sound insulation material for commercial use.


2017 ◽  
Vol 898 ◽  
pp. 1717-1723 ◽  
Author(s):  
Xue Mei Yi ◽  
Shota Suzuki ◽  
Xiong Zhang Liu ◽  
Ran Guo ◽  
Tomohiro Akiyama

Combustion synthesis (CS) of β-SiAlON was conducted using a 3D ball mill, with a focus on the effect of the 2D/3D ball mill premixing conditions on the CS raw material particle size as well as on the yield and grain shape of the final products. The results showed that the particle size distribution of the raw materials was significantly affected by the premixing conditions. Various particle sizes and particle size distributions could easily be obtained by using a 3D mill instead of a 2D mill due to the complex biaxial rotation movement of 3D milling. The particle size was more sensitive to the rotation ratio (vertical spin/horizontal spin, Vv/Vh) than the rotation rate when using 3D milling. Finally, β-SiAlON with less than 5 mass% unreacted Si was obtained using premix milling conditions of 135×200 [vertical spin (rpm) × horizontal spin (rpm)]. The grain shapes of the final products were clearly influenced by the particle size distribution of the raw mixtures.


2010 ◽  
Vol 8 (4) ◽  
pp. 783-788 ◽  
Author(s):  
Jihui Li ◽  
Huiqing Shi ◽  
Ning Li ◽  
Mei Li ◽  
Jing Li

AbstractGraphite intercalation compounds are often prepared by flake graphite, oxidants, inorganic acids, organic acids and intercalated ions which are usually hydrogen protons between the graphene planes. They are also known as the acid-treated graphite intercalation compounds. In this work, alkaline graphite intercalation compounds were prepared by flake graphite, K2Cr2O7, concentrated H2SO4 and NaOH, and the morphology and structure were characterized by Electron microscopy and X-ray techniques. The results display that the combination of neutralisation heat and oxidation capability produced by K2Cr2O7 can break the bonds to produce the spaces between the graphene planes and hydroxyl ions also intercalate into the graphene planes to form alkaline graphite intercalation compounds in alkali solution. The morphology and structure of alkaline graphite intercalation compounds are analogous to the ones of the acid-treated graphite intercalation compounds, but the intercalated ions and the expansion volume are different. The results show that the method is an innovation.


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