Binder Pitch Research Articles

Interaction between Nuclear Graphite and Molten Fluoride Salts: A Synchrotron Radiation Study of the Substitution of Graphitic Hydrogen by Fluoride Ion

The interaction between nuclear graphite and molten fluoride salts (46.5 mol % LiF/11.5 mol % NaF/42 mol % KF) is investigated by synchrotron X-ray diffraction and C K-edge X-ray absorption near-edge structure (XANES). It is found that there are a large number of H atoms in IG-110 nuclear graphite, which is attributed to the residual C-H bond after the graphitization process of petroleum coke and pitch binder. The elastic recoil detection analysis indicates that H atoms are uniformly distributed in IG-110 nuclear graphite, in excellent agreement with the XANES results. The XANES results indicate that the immersion in molten fluoride salts at 500 °C led to H atoms in nuclear graphite partly substituted by the fluorine from fluoride salts to form C-F bond. The implications of these findings are discussed.

Electrophysical properties of composition based on natural flake graphite and binder

The electrophysical properties of a highly filled composition based on natural flake graphite and coal tar pitch as a binder have been studied. Blanks have been obtained in a laboratory broaching press. The conductivity of pitch binder interlayers in the composition has been varied by heat treatment, and the electric resistivity and magnetoresistance along and across the texture axis have been measured. The thickness and imperfection of surface layers of graphite flakes have been assessed. The formation of structural defects of the surface layers is associated with a decrease in the size of mosaic blocks as a result of friction between flakes during mass movement under pressure in the conical part of the die. It has been shown that friction forces facilitate consolidation of the material and ensure directed orientation of stacks.

Graphite blocks with preferred orientation and high thermal conductivity

Graphite blocks were prepared from natural graphite (NG) flake and mesophase pitch powder by a hot-pressing technique at a relatively low temperature (500 °C). The effect of pitch binder content and heat-treatment temperature on the physical properties of the graphite blocks was investigated. X-ray analyses indicate that the graphite block has a highly preferred structural orientation, and field emission scanning electron microscopy and polarized light microscopy observations further prove that the graphitic layers of the graphite flakes are clearly oriented perpendicular to the hot-pressing direction. Graphitized blocks prepared from 86 wt.% NG and 14 wt.% mesophase pitch have a low electrical resistivity of 1.45 μΩ m and a high thermal conductivity of 522 W/m K, as well as a high thermal diffusivity of 396 mm 2/s in the direction perpendicular to the hot-pressing direction at room temperature.

Molasses and air blown coal tar pitch binders for the production of metallurgical quality formed coke from anthracite fines or coke breeze

The effect of the type and the amount of hardeners, such as ammonium nitrate, ammonium carbonate and nitric acid on the molasses bonded briquettes prepared from anthracite fines or coke breeze were investigated. Amongst the hardener studied the best results were obtained with 2.5% ammonium nitrate hardener. The briquettes produced with this hardener were highly water resistant but not waterproof and their tensile strengths were not adequate to be used as a substitute for the metallurgical coke. Therefore, the briquettes were prepared with molasses containing 2.5% ammonium nitrate hardener and air blown coal tar pitch blended binder. When the blended binder was used for the production of anthracite fines or coke breeze briquettes, after curing at 200°C for 2h, they became waterproof and their tensile strengths were found to be sufficient to be used as a substitute for coke oven coke. The briquettes after curing could be directly charged into the blast furnace without carbonizing them at high carbonization temperatures. Since molasses and coal tar pitch, are relatively cheap and readily available materials, the process investigated could be economical way of producing high quality formed coke.

Influence of filler type on the performance and microstructure of a carbon/graphite material

Carbon/graphite material was prepared by subjecting a mixture of coaltar pitch binder and a relevant filler to uniaxial compression at 150MPa for 10min, followed by calcination at 1300℃ for 1 h, and graphitization at 2300℃ in an induction furnace. Four fillers, carbon black (CB), petroleumcoke powder, needlecoke powder, and natural graphite powder (NG), were used. The effect of filler type on the performance and microstructure of the material was investigated. Results reveal that the CBbased material has excellent flexural and compressive strength, with the highest values of 88.0 and 173.2MPa, respectively, but poor thermal and electrical conductivity. The thermal conductivity of the NGbased material has the highest value of 278W/m·K, but the flexural and compressive strength are limited to 51.1 and 90.2MPa, respectively. Microstructural analysis showed that the NGbased material has the largest crystallite size, as well as the most perfect orientation of graphite layers.

Influence of filler type on the performance and microstructure of a carbon/graphite material

Carbon/graphite material was prepared by subjecting a mixture of coal-tar pitch binder and a relevant filler to uniaxial compression at 150 MPa for 10 min, followed by calcination at 1 300 °C for 1 h, and graphitization at 2 300 °C in an induction furnace. Four fillers, carbon black (CB), petroleum-coke powder, needle-coke powder, and natural graphite powder (NG), were used. The effect of filler type on the performance and microstructure of the material was investigated. Results reveal that the CB-based material has excellent flexural and compressive strength, with the highest values of 88.0 and 173.2 MPa, respectively, but poor thermal and electrical conductivity. The thermal conductivity of the NG-based material has the highest value of 278 W/m·K, but the flexural and compressive strength are limited to 51.1 and 90.2 MPa, respectively. Microstructural analysis showed that the NG-based material has the largest crystallite size, as well as the most perfect orientation of graphite layers.

Thermostable Adsorption Filter Immobilized with Super Activated Carbons by Quinoline Soluble Isotropic Pitch Binder (I-a Novel Adsorption Filter)

Among other filters such as light filter, wave filter, air filter, ultra filter and filter paper, a novel adsorption filter from thermostable polyester nonwoven fabrics immobilized with functional super activated carbon by means of quinoline soluble, activateable isotropic pitch binder were developed in this study. The activated carbon precursor is available in the market branded as coconut shell based activated carbon(CCS-AC) produced by Dongyang Carbon Co. Ltd. BET-surface area of this precursor was 1,355 m2/g, after KOH-activation it increased over 2,970 m2/g and was named as super activated carbon. In the preliminary research, this precursor was impregnated with PdCl2(0.188 wt%) KMnO4(3 wt%) and redox-agent(CuCl2, 0.577 wt%) in order to promote TOF up to 100/h and Selectivity up 99% and patented as a functional AC for the ethylene adsorption. The enhancement of the isotropic pitch binder to the AC-immobilized adsorption filter was BET-surface area upgraded by 266 m2/g and promoted the Iodine- and MB-adsorption by 1.4 times, respectively and also micro pore wide ranges 〈 5a~30 a 〉.

Multi-impregnating pitch-bonded Egyptian dolomite refractory brick for application in ladle furnaces

A method of preparation of multi-impregnated pitch-bonded Egyptian dolomite refractory brick for ladle furnace is described. Brick samples were prepared from blend of calcined dolomite mineral and coal tar pitch. The blend was hot mixed and pressed under a compression force up to 151 MPa. Green bricks were baked for 2 h at temperatures up to 1000 °C. Voids in the baked bodies were filled with carbon by multiple impregnations using low-softening point coal tar pitch. Each impregnation step (30 min) was followed by calcination at 1000 °C. Brick samples containing 8–12 wt.% coal tar pitch binder and pressed under 108–151 MPa acquired quantify crushing strength. However, multi-impregnating favored the mechanical strength of the baked brick samples and improved their hydration resistance (>45 days). Dolomite brick samples containing 10 wt.% coal tar pitch and pressed at 108 MPa gave high hydration resistance (more than 60 days in normal condition) compared to the hydration resistance of the commercial bricks (30 days). The prepared brick samples have acceptable density, chemical stability, outstanding resistance and good mechanical properties would meet the requirements of Ladle furnace (LF) for steel making industry. In addition, estimation of production cost of the brick indicates it is competitive with the market price based on durability and service life time aspects.

Heat treatment of medium-temperature Sasol–Lurgi gasifier coal-tar pitch for polymerizing to higher value products

Two coal-derived pitch samples, one a medium temperature pitch from a Sasol–Lurgi gasifier and the other from a high temperature coking process, have been heat treated to induce polymerization, both separately and as a mixture of pitches (co-pyrolysis). The initial pitch samples and the heat-treated samples have been examined by size exclusion chromatography (SEC) in 1-methyl-2-pyrrolidinone (NMP), by UV-fluorescence spectroscopy (UV-F), by solid state 13C NMR; elemental analyses of the initial pitch samples have been carried out. The Sasol–Lurgi pitch showed larger apparent sizes, more alkyl and carbonyl functions, and smaller polycyclic aromatic hydrocarbon (PAH) groups than the high temperature pitch. Co-pyrolysis of the two pitches indicated that polymerized product from the Sasol–Lurgi pitch can be used as an extender for high-temperature binder pitch.

석탄계 피치를 이용한 고밀도 흑연 제조

Graphite has hexagonal closed packing structure with two bonding characteristics; (1) van der waals bonding between c axis, and (2) covalent bonding in the a and b axis. The weak van der waals bonds cause self-lubricant property, and the strong covalent bonds cause excellent electric and thermal conductivity. Furthermore, graphite is chemically very inert because of the material composed of only carbon elements. Thus, graphite is very useful for mechanical sealing materials. However, Graphite have porous microstructure because starting materials of graphite produce many volatile during the manufacturing processes. This causes low density of graphite, which is unsuitable for the mechanical sealing materials. Thus, further impregnation process is generally needed to enhance the graphite density. In this work, high density graphite is prepared with the principle of densification when coke and pitch binder, prepared from thermal treatment of coal tar pitch, become dehydrogenation during graphitization or carbonization.

Characterization of AC/TiO2 Composite Prepared with Pitch Binder and Their Photocatalytic Activity

In this study, we have prepared pitch binded AC (activated carbon)/<TEX>$AC/TiO_2$</TEX> composites photocatalysts through carbon tetrachloride solvent method. The developed samples were characterized with surface properties, structural crystallinity between AC and <TEX>$AC/TiO_2$</TEX>, elemental identification and photocatalytic activity. The results of the textural surface properties demonstrate that there are slight increases in the BET surface area and adsorbed volume from adsorption isotherm of composite samples with increasing of the amount of AC. The SEM results present to the characterization of porous texture on the pitch/AC/<TEX>$AC/TiO_2$</TEX> composites and homogenous compositions in the particle for all the materials used. From XRD data, a weak and broad carbon peak of graphene remained rutile peaks kept with anatase structure were observed in the X-ray diffraction patterns for the pitch/AC/<TEX>$AC/TiO_2$</TEX> composites. The EDX spectra show the presence of C, O and S with strong Ti peaks. Most of these samples are richer in carbon and major Ti metal than any other elements. Finally, the excellent photocatalytic activity of the pitch/AC/<TEX>$AC/TiO_2$</TEX> composites between relative concentration (<TEX>$c/c_o$</TEX>) of MB and UV irradiation time could be attributed to the both effects between photocatalysis of the supported <TEX>$AC/TiO_2$</TEX> and adsorptivity of the two kinds of carbons.

Selected Rheological Properties of Tall Oil Pitch Binder for Asphaltic Road Pavement Construction

Tall oil pitch is a secondary by-product of the coniferous wood pulp industry. Its use as a pavement binder is problematic as the basic rheological properties are affected by variable chemical composition of the tall oil pitch. Synthetic blends of fatty acid, resin acid and sterol were used as model compounds for the laboratory study of the effect of chemical composition on the physical properties of tall oil pitch. A reliable empirical method has been developed to predict the key rheological properties of tall oil pitch. Tall oil pitch could thus be altered by means of compositional changes to meet the pavement engineering needs of different climatic service conditions.

New directions for non-fuel uses of anthracites

Anthracites contain over 90% carbon, most of which is in the form of large, polycyclic aromatic sheets. The high carbon content and the highly aromatic nature give anthracites great potential for conversion to high-value carbon materials. This paper reviews previous work and summarizes the present status of conversion of anthracites to four types of premium carbon materials: molded or extruded graphites, binder pitch, activated carbons, and exfoliated carbons. Significant opportunities exist for the non-fuel uses of anthracites in these applications.

04/01788 Precise measurement of density of coal tar oil and liquid binder pitch: Yoon, K. et al. Light Metals, 2003, 503–507

04/01788 Precise measurement of density of coal tar oil and liquid binder pitch: Yoon, K. et al. Light Metals, 2003, 503–507

New directions for non-fuel uses of anthracites

Anthracites contain over 90% carbon, most of which is in the form of large, polycyclic aromatic sheets. The high carbon content and the highly aromatic nature give anthracites great potential for conversion to high-value carbon materials. This paper reviews previous work and summarizes the present status of conversion of anthracites to four types of premium carbon materials: molded or extruded graphites, binder pitch, activated carbons, and exfoliated carbons. Significant opportunities exist for the non-fuel uses of anthracites in these applications.

Sorption of H2, D2, N2 and Ar by CsC24 prepared from carbons heat treated at different temperatures

CsC24 samples were prepared from artificial graphite materials, derived from petroleum cokes and additional pitch binder, with different heat-treatment temperatures (HTTs) between 1300 and 2800°C. The sorption isotherms for the systems, CsC24-H2, -D2, -N2 and-Ar at 77K were determined. All the CsC24 samples were able to take up these molecules, irrespective of the HTT of the host materials. The saturated amount of sorption, (nmolecule/nCs) sat., increased with HTT of the host carbons. For H2-and D2-sorption, (nmolecule/nCs) sat. increased monotonically with HTT from HTT-1300 up to-2000, and then stepwise increase was observed from HTT-2000 up to -2800. This behavior was considered to be a manifestation of the drastic change of the structure of host carbons at around HTT-2000. The sorption isotherms were well fitted by the Langmuir equation. This fact suggested the sorbed molecules are accommodated in the interlayer nanospace even for CsC24 samples prepared from carbons with low HTT such as HTT-1300.

03/02137 Transforming coal into premium carbon products: an outlook: Andresen, J. M. et al. Preprints of Symposia — American Chemical Society, Division of Fuel Chemistry, 2003, 48, (1), 22–23

Introduction The great abundance of coal in the U.S. carries an inherent potential of introducing benign and affordable premium carbon products to the general public (1). Low cost carbon fibers from coal could ensure lighter vehicles and result in a tremendous rise in energy efficiency for the traffic sector. Large production of inexpensive activated carbon could significantly increase the use of activated carbon in water treatment facilities thus vastly improve water quality throughout US. Further, high quality binder pitches and cokes for anodes in the aluminum industry and electrodes for the steel industry can be derived from coal. An industry driven consortium, Consortium for Premium Carbon Products from Coal, has for the last four years strived for the recognition of coal as a valuable resource for producing premium carbon products and some of its recent advances are discussed.

An improvement of thermal conduction of activated carbon by adding graphite

This study was performed to improve thermal conduction of granular activated carbon by adding graphite powder. Granular activated carbons were fabricated from anthracites and graphite powders using a binder pitch, and then activated in a nitrogen-carbon dioxide gas at 850°C. Additions of graphite from 20 to 30 wt% were considered to be suitable for thermal conductivity and n-butane adsorption power. The thermal conductivities of such granular activated carbons were 20 times those of activated carbons without graphite. A fixed bed filled with the granular or powder activated carbons containing graphite were never ignited even though the inside of the bed was directly heated.

Activated carbon fibre monoliths

Activated carbon fibre monoliths were prepared by physical activation of carbon fibre monoliths derived from two kinds of pitch-based carbon fibre (CF) (carbon fibres from a coal tar pitch and carbon fibres derived from a petroleum pitch). The monoliths were conformed using a coal tar pitch binder. The carbon fibre monoliths and the activated carbon fibre monoliths were studied by scanning electron microscopy (SEM) and gas adsorption (i.e. N 2 at 77 K and CO 2 at 273 K). The results obtained reveal that monoliths perform a good activation process that produce a quite high development of microporosity (BET surface areas around 2600 m 2/g and N 2 micropore volume of 1.23 cm 3/g). On the other hand, it is remarkable that the activation process used allow to easily control the degree of activation and hence to select the adsorption capacities of the activated carbon fibre monoliths.

Preparation of binder pitches by blending coaltar and petroleum pitches

Preparation of binder pitches by blending coaltar and petroleum pitches