scholarly journals Purification of Indonesian Natural Graphite by Acid Leaching Method as Nuclear Fuel Matrix: Physical Characterization

2019 ◽  
Vol 11 (1) ◽  
pp. 9 ◽  
Author(s):  
Deni Mustika ◽  
Torowati Torowati ◽  
Sudirman Sudirman ◽  
Adel Fisli ◽  
I M. Joni ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Nuclear Fuel ◽  
Matrix Material ◽  
Chemical Properties ◽  
Acid Leaching ◽  
Average Diameter ◽  
Natural Graphite ◽  
Graphite Sample ◽  
Pebble Bed Reactor ◽  
Graphite Matrix

Graphite matrix in Pebble Bed Reactor (PBR) fuel has an important role not only as neutron moderator and structural material to protect nuclear fuel, but also as heat transfer media. Therefore, the graphite matrix must meet the criteria of physical and chemical properties specified for PBR fuel. This paper focuses on the purification of the Indonesian natural graphite by using hydrometallurgy method with acid treatments. The characteristic of the purified graphite was studied for its specification compliance as a candidate of fuel matrix for PBR type of High Temperature Gas Cooled Reactor (HTGR). Acid and acid mixtures such as HF, HNO3+H2SO4 and HF+HCl+H2SO4 were used for the purification process. Crystal structure examination by X-Ray Diffraction indicates that the graphite sample was 2H poly type with hexagonal crystal structure and lattice group of P 63 m c space group. It was observed that the graphite sample purified by HNO3+H2SO4 mixture had the closest resemblance to single crystalline graphite with a <d002> deviation of 0.94 when compared to perfect graphite crystal. The density of graphite decreases from 2.3273 g/cm3 (before acid treatment) to 2.1808; 2.2203 and 2.2752 g/cm3 after treatment with HF, HNO3+H2SO4 and HF+HCl+H2SO4, respectively. These results are close to the theoretical density value of 2.26 g/cm3. The surface area decreases from 10.346 m2/g to 6.177; 5.831 and 7.63 m2/g for the treated graphite with HF, HNO3+H2SO4 and HF+HCl+H2SO4 respectively. However, these values are still higher than that of nuclear grade graphite (i.e. between 4.80 and 5.55 m2/g). The average diameter size of graphite decreased from 29.65 μm (before treated acid) into 23.12 μm (after treated acid). The Indonesian natural graphite obtained from acid purification treatment is potential to be used as matrix material for PBR - HTGR fuel, but further treatment is necessary.

scholarly journals PURIFICATION OF INDONESIAN NATURAL GRAPHITE AS CANDIDATE FOR NUCLEAR FUEL MATRIX BY ACID LEACHING METHOD: CHEMICAL CHARACTERIZATION

2020 ◽  
Vol 26 (3) ◽  
Author(s):  
Deni Mustika ◽  
Torowati Torowati ◽  
Arbi Dimyati ◽  
Sudirman Sudirman ◽  
Adel Fisli ◽  
...  
Keyword(s):  
Sulphuric Acid ◽  
Nuclear Fuel ◽  
Hydrofluoric Acid ◽  
Acid Leaching ◽  
Chemical Characterization ◽  
Ash Content ◽  
Natural Graphite ◽  
Nuclear Graphite ◽  
Purity Level ◽  
Graphite Matrix

PURIFICATION OF INDONESIAN NATURAL GRAPHITE AS CANDIDATE FOR NUCLEAR FUEL MATRIX BY ACID LEACHING METHOD: CHEMICAL CHARACTERIZATION. Graphite matrix in Pebble Bed Reactor (PBR) – High Temperature Gas Cooled Reactor (HTGR) has an important role as heat transfer medium, neutron moderator and structural material to protect fuel. Thus, graphite matrix must fulfill chemical and physical characteristics for PBR-HTGR fuel. Indonesia has graphite sources in several regions that can potentially be purified. This research aimed to purify Indonesian natural graphite by several variation of acids and to perform chemical characterizations. Natural graphite from flotation process was purified by several variations of acid, i. e., hydrofluoric acid (HF), sulphuric acid + nitric acid (H2SO4 + HNO3) and hydrofluoric acid + hydrochloric acid + sulphuric acid (HF + HCl + H2SO4) and subsequently followed by chemical characterizations such as purity level, ash content, and boron quivalent. The highest purity was obtained in the purification process by HF with carbon content up to 99.52%; this purity level fulfills the specification of nuclear graphite (>99%). Ash content analysis shows a value in compliance with the specification requirement, i.e., < 100 ppm, and boron equivalent value also fulfills the specification value of < 1 ppm. It can be concluded from this study that the graphite purified by acid leaching with HF can be used as fuel matrix candidate but is qualified as low quality. Futher research is required to produce high quality nuclear graphite, particularly research in the minimization of the impurity by evaporation at temperatures over 950 oC to by far lower the ash content.Keywords:  Indonesian natural graphite, purification, nuclear fuel matrix, acid leaching, chemical characterization.

New-dimensional cyclam. Synthesis, crystal structure, and chemical properties of macrocyclic tetraamines bearing a phenol pendant

1987 ◽  
Vol 26 (18) ◽  
pp. 2975-2983 ◽  
Author(s):  
Eiichi Kimura ◽  
Tohru Koike ◽  
Keiji Uenishi ◽  
Markus Hediger ◽  
Miyuki Kuramoto ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Chemical Properties ◽  
And Chemical Properties

scholarly journals The Impact of Filler Geometry on Polylactic Acid-Based Sustainable Polymer Composites

Molecules ◽  
2020 ◽  
Vol 26 (1) ◽  
pp. 149
Author(s):  
Karol Leluk ◽  
Stanisław Frąckowiak ◽  
Joanna Ludwiczak ◽  
Tomasz Rydzkowski ◽  
Vijay Kumar Thakur
Keyword(s):  
Polymer Composites ◽  
Polylactic Acid ◽  
Matrix Material ◽  
Chemical Properties ◽  
Precipitated Calcium Carbonate ◽  
Cellulose Fibres ◽  
Shape Factors ◽  
Pure Cellulose ◽  
Physico Chemical ◽  
The Impact

Recently, biocomposites have emerged as materials of great interest to the scientists and industry around the globe. Among various polymers, polylactic acid (PLA) is a popular matrix material with high potential for advanced applications. Various particulate materials and nanoparticles have been used as the filler in PLA based matrix. One of the extensively studied filler is cellulose. However, cellulose fibres, due to their hydrophilic nature, are difficult to blend with a hydrophobic polymer matrix. This leads to agglomeration and creates voids, reducing the mechanical strength of the resulting composite. Moreover, the role of the various forms of pure cellulose and its particle shape factors has not been analyzed in most of the current literature. Therefore, in this work, materials of various shapes and shape factors were selected as fillers for the production of polymer composites using Polylactic acid as a matrix to fill this knowledge gap. In particular, pure cellulose fibres (three types with different elongation coefficient) and two mineral nanocomponents: precipitated calcium carbonate and montmorillonite were used. The composites were prepared by a melt blending process using two different levels of fillers: 5% and 30%. Then, the analysis of their thermomechanical and physico-chemical properties was carried out. The obtained results were presented graphically and discussed in terms of their shape and degree of filling.

Materials and Photosensor Devices with High Radiation Stability

2015 ◽  
Vol 1117 ◽  
pp. 107-113 ◽  
Author(s):  
Ilariy Rarenko ◽  
Dmytro Korbutyak ◽  
Volodymyr Koshkin ◽  
Boris Danilchenko ◽  
Leonid Kosyachenko ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Metal Layer ◽  
Chemical Properties ◽  
Radiation Stability ◽  
Reactor Irradiation ◽  
High Concentration ◽  
High Radiation ◽  
Cubic Crystal ◽  
Impurity Atoms ◽  
Mixed Reactor

Semiconductor Hg3In2Te6 crystals and their analogous are solid solutions of In2Te3 and HgTe. Hg3In2Te6 crystals are congruently melted as chemical compound. Like In2Te3 the Hg3In2Te6 crystal has cubic crystal lattice with stoichiometric vacancies in their crystal structure. The electroconductivity, photoconductivity, mechanical, chemical properties of the crystals do not deteriorate after their irradiation by γ-photons with energies up to 1 MeV and doses up to 1018 cm-2 , by electrons with energies up to 300 MeV and doses up to 1019 cm-2 and by mixed reactor irradiation (filtered slow neutrons) with doses up to 1019 cm-2 [1,2]. This feature is determined by high concentration (~1021 cm-3) of stoihiometric vacancies (Vs) in crystal structure, where every third In-cation node is empty. These Vs are electroneutral, they capture all impurity atoms in these crystals and kept them in electroneutral state too. On the other hand this feature doesn't allow to form direct p-n junctions in these crystals by introducing the impurities. However, we have developed p-n junction analogues in form of Schottki diodes and corresponding photodiodes with semitransparent metal layer on single crystal Hg3In2Te6 substrate that allows irradiation to get into active region preserving this way all the advantages compared to p-n junction.

Molecular crystal structure and chemical properties of 4-phenyl-3,5-diethoxycarbonyl-1,2,6-trimethyl-1,2-dihydropyridine

1991 ◽  
Vol 27 (9) ◽  
pp. 995-998 ◽  
Author(s):  
M. F. Bundule ◽  
A. F. Mishnev ◽  
V. K. Lusis ◽  
D. Kh. Mutsenietse ◽  
A. Z. Zandersons ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Molecular Crystal ◽  
Chemical Properties ◽  
And Chemical Properties

scholarly journals Features of Waste Chemical Processing Germanium Concentrates

2020 ◽  
Author(s):  
Igor Nikolaevich Tanutrov ◽  
Marina Nikolaevna Sviridova
Keyword(s):  
Chemical Properties ◽  
Average Diameter ◽  
Toxic Waste ◽  
High Temperature Treatment ◽  
High Dispersion ◽  
Chemical Processing ◽  
Particle Sizes ◽  
Physical And Chemical Properties ◽  
Physical And Chemical ◽  
And Chemical Properties

In order to increase the extraction of germanium in the technology of production of germanium concentrates, as well as finding ways to eliminate the accumulation of toxic waste using modern techniques and equipment, the physical and chemical properties of waste chemical processing of germanium concentrates (OHGC) of two domestic enterprises were experimentally studied. The main components of OHGC are: sulphate hemihydrate CaSO4·0.5H2O and hypochlorite Ca(OCl)2 calcium. The moisture content of the sludge amounted to 30–50 %. The content of germanium in the cakes of both companies is in the range of 0.20 and 0.27 %, respectively, indicating the feasibility of recovery in the Ge. At the same time, the samples of cakes differ significantly in the content of impurities, which depends on the types of raw materials in the preparation of concentrates. Granulometric composition of cakes is characterized by high dispersion. With an average diameter of 12 μm, all particle sizes are in the range of 0.5-15 μm. The distribution of particle sizes is shifted in interval of 0–15 μm, and the area of the particles less than 3 μm is not more than 10 %. The high dispersion of the cake is reflected in the specific surface area, which is 23.7 m2/g. Thermographic study found that the heating of the sample cake is accompanied by two endothermic effects of dehydration at 110 and 145–168 ∘C calcium sulfate and hypochloride semihydrate with corresponding weight loss of 13.1 and 12.9 %. The presence of toxic impurities (arsenic, zinc and lead), as well as chlorine, presents significant challenges for the development of disposal technology with the extraction of germanium. Assuming that the undiscovered part of the germanium in the concentrate is compounds or solid solutions with silicon dioxide, an effective technology should include their reagent high temperature treatment. Keywords: waste, germanium concentrate, chemical processing, waste, physical and chemical properties

scholarly journals SINTESIS DAN KARAKTERISASI NANOFIBER KOMPOSIT Zn-PVDF KOPOLIMER

2014 ◽  
Vol 16 (1) ◽  
pp. 49-52
Author(s):  
Yelfira Sari ◽  
Muhamad Nasir ◽  
Chandra Risdian ◽  
Syukri Syukri
Keyword(s):  
Crystal Structure ◽  
Phase Structure ◽  
Research Study ◽  
Fiber Diameter ◽  
Average Diameter ◽  
Nanofiber Composite ◽  
Β Phase ◽  
Α Phase ◽  
Structure Morphology ◽  
Electrospinning Method

Sintesis nanofiber komposit Zn-PVDF kopolimer dengan metoda elektrospinning telah berhasil dilakukan. Proses pembuatan nanofiber komposit serta  morfologi yang terbentuk dipengaruhi oleh penambahan Zn-asetat dengan perubahan diameter rata-rata serat dari 357,13 nm menjadi 777,24 nm. Analisis FTIR menunjukkan bahwa struktur kristal nanofiber komposit Zn-PVDF kopolimer didominasi oleh strukturβ-phase, dengan bilangan gelombang 1190,08 cm-1 dan 487,99 cm-1 untuk struktur α-phase dan 1404,18 cm-1; 1280,73 cm-1; 1074,35 cm-1; 881,47 cm-1; dan 840,96 cm-1 untuk struktur β-phase.Kata kunci :nanofiber komposit, Zn-PVDF kopolimer komposit, elektrospinning,kristal struktur, morfologi, diameter fiber The fabrication of Zn-PVDF copolymer nanofiber composite has been investigated in this research study by using electrospinning method. Fabrication and morphology of nanofiber composite is influenced by the addition of Zn-acetate. The average diameter of nanofiber composites increase with an addition of Zn-acetate, from 357,13 to 777,24nm. FTIRanalysisshowedthat thecrystalstructure ofPVDFnanofiberis dominatedby β-phase , thewave number 1190,08 cm-1 and 487,99 cm-1 for α-phase structure and 1404,18cm-1; 1280,73cm-1; 1074,35cm-1; 881,47cm-1and840,96cm-1 for β-phase structure respectively.Key words : nanofiber composite, Zn-PVDF copolymer composite, electrospinning, crystal structure,  morphology, fiber diameter

Fibrous Minerals and Synthetic Fibers

1989 ◽  
Author(s):  
H. Catherine W. Skinner ◽  
Malcolm Ross ◽  
Clifford Frondel
Keyword(s):  
Crystal Structure ◽  
Chemical Composition ◽  
Chemical Properties ◽  
Type Specimen ◽  
Mineral Species ◽  
X Ray Diffraction ◽  
X Ray ◽  
Synthetic Fibers ◽  
Fibrous Minerals ◽  
The Common

A mineral is a naturally occurring, crystalline inorganic compound with a specific chemical composition and crystal structure. Minerals are commonly named to honor a person, to indicate the geographic area where the mineral was discovered, or to highlight some distinctive chemical, crystallographic, or physical characteristic of the substance. Each mineral sample has some obvious properties: color, shape, texture, and perhaps odor or taste. However, to determine the precise composition and crystal structure necessary to accurately identify the species, one or several of the following techniques must be employed: optical, x-ray diffraction, transmission electron microscopy and diffraction, and chemical and spectral analyses. The long history of bestowing names on minerals has provided some confusing legacies. Many mineral names end with the suffix “ite,” although not most of the common species; no standard naming practice has ever been adopted. Occasionally different names have been applied to samples of the same mineral that differ only in color or shape, but are identical to each other in chemical composition and crystal structure. These names, usually of the common rock-forming minerals, are often encountered and are therefore accepted as synonyms or as varieties of bona fide mineral species. The Fibrous Minerals list (Appendix 1) includes synonyms. A formal description of a mineral presents all the physical and chemical properties of the species. In particular, distinctive attributes that might facilitate identification are noted, and usually a chemical analysis of the first or “type” specimen on which the name was originally bestowed is included. As an example, the complete description of the mineral brucite (Mg(OH)2), as it appears in Dana’s System of Mineralogy, is presented as Appendix 3. Note the complexity of this chemically simple species and the range of information available. In the section on Habit (meaning shape or morphology) both acicular and fibrous forms are noted. The fibrous variety, which has the same composition as brucite, is commonly encountered (see Fig. 1.1D) and is known by a separate name, “nemalite.” Tables to assist in the systematic determination of a mineral species are usually based on quantitative measurements of optical properties (using either transmitted or reflected light, as appropriate) or on x-ray diffraction data.

Investigation of Tensile Property of Aluminium SiC Metal Matrix Composite

2015 ◽  
Vol 766-767 ◽  
pp. 252-256 ◽  
Author(s):  
A. Siddique Ahmed Ghias ◽  
B. Vijaya Ramnath
Keyword(s):  
Composite Material ◽  
Metal Matrix Composite ◽  
Matrix Composite ◽  
Metal Matrix ◽  
Matrix Material ◽  
Chemical Properties ◽  
High Strength ◽  
Stir Casting ◽  
The Matrix ◽  
Hybrid Metal Matrix Composite

The composite material is a combination of two or more materials with different physical and chemical properties. The composite has superior characteristics than those individual components. A hybrid composite is the one which contains at least three materials. When the matrix material is a metal, the composite is termed as metal matrix composites (MMC). The MMC is a composite material with two constituent parts, one being a metal. The other material may be another metal, ceramic or fiber. Among all the MMC’s, Aluminium is the most widely used matrix material due to its light weight, high strength and hardness. This paper deals with the fabrication and mechanical investigation of hybrid metal matrix composite Al - SiC. The fabrication is done by stir casting by adding the required quantities of additives into the stirred molten Aluminium. The results show significant effect of mechanical properties such as tensile strength, yield stress and flexural strength. The internal structure of the composite is observed using Scanning electron microscope (SEM) and found that are formation of pores in them.

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