Showing papers by "Cabot Corporation published in 1993"

The Influence of Fumed Silica Properties on the Processing, Curing, and Reinforcement Properties of Silicone Rubber

Abstract: The present study uses a commercial heat cured silicone rubber formula (including a process aid) and mixing techniques to investigate the effect of varying fumed silica properties—includin...

Low ash carbon blacks

Abstract: Novel furnace carbon blacks that impart advantageous properties to rubber and plastic compositions and may be utilized in the place of acetylene blacks. The furnace carbon blacks have an ash level less than or equal to 50 ppm, preferably less than or equal to 30 ppm, most preferably less than or equal to 10 ppm, a sulfur level less than or equal to 50 ppm, preferably less than or equal to to 30 ppm most preferably less than or equal to 10 ppm, an L~ less than or equal to 30 .ANG. and an L c less than or equal to 30 .ANG.. Also disclosed are novel rubber and plastic compositions incorporating the novel furnace carbon blacks which exhibit advantageous properties, particularly in extending the useful service life of power cables produced using the compositions.

Process for uniformly moisturizing fumed silica

Abstract: An improved process for uniformly distributing high levels of water in hydrophilic fumed silica by mixing with dry water.

Extruded capacitor electrode and method of making the same

Abstract: Tantalum electrode material is produced which has extremely low tortuosity, exceptionally low ESL and ESR, extended high frequency performance, very high volumetric efficiency, and reduced tantalum consumption per anode. The anode material is characterized by having a cross section composed of plates of tantalum separated by spaced gaps resulting in a highly dense (volumetric efficiency) electrode. The plates are electrically interconnected which also adds to the structural stability of the article. This is made possible by being able to carefully control the geometry of the tantalum material during processing. A method for producing such material includes extruding a billet filled with a (preferentially geometrically uniform) mixture of rods of tantalum and an extrudable metal. When the billet has been sufficiently reduced in size and severed, the extrudable metal is removed by selectively dissolving with acid. In addition to the above advantages, the resulting article is particularly adapted for use in super-miniaturization applications.

Process for producing carbon blacks and new carbon blacks

Abstract: A process for producing carbon blacks comprised of mixing an oxidant, primary fuel, and carbon black feedstock to form carbon black particles and aggregates, passing the mixture through a reactor, cooling, separating, and recovering the carbon black product. The improvement comprises the addition of a secondary oxidant-containing stream to the reactor such that the secondary oxidant stream does not interfere with the formation of the carbon black particles and aggregates in the reactor. Also disclosed are new carbon black products defined by the following parameters: 35 m2/g « I?2? No. « 65 m?2?/g; 30 m2/g « CTAB « 55 m2/g; 1.12 « I?2? No./CTAB ratio; Tint « 65 %; 75 cc/100 g « CDBP « 95 cc/100 g. Also disclosed are rubber and/or plastic compositions containing these new carbon blacks.

Pilot scale study and design of a granular activated carbon regeneration process using supercritical fluids

Abstract: A technology which has great potential for environmental control and waste remediation is contaminant removal and separation with supercritical fluids (SCF's) or supercritical fluid extraction (SFE). Pressure tuning of solvent power allows SCF processes to adapt to a wide variety of small batch oriented separations typified by environmental cleanup operations. The ability of supercritical CO[sub 2] to extract model contaminant compounds from GAC and subsequently drop out most of the contaminant in a liquid phase has been investigated in a pilot scale apparatus. Typical desorption profiles indicate an 85% removal of the compound from the carbon which allows for reuse. The desorption results have been interpreted with a generalized desorption-mass transfer model. The results of the pilot plant studies have been applied to the design of a fixed-site GAC regeneration unit consisting of a three-element desorber with two-stage flash separation. Optimization of the process centers around minimizing the cost of recycling the SCF through an efficient recompression scheme and cycle configuration in the desorber unit. An economic evaluation shows a processing cost of 10.6 cents/lb (23 cents/kg) GAC which compares favorably with thermal regeneration and incineration. This non-destructive process allows re-use of the GAC while maintaining a high adsorbate capacity,more » which reduces carbon replacement costs and significantly decreases the need for carbon disposal by landfill or incineration. 25 refs., 13 figs., 3 tabs.« less

Recovery of metal values from process residues

Abstract: A process for recovering metal (17) and acid values (48) from a source material (22) containing metallic fluorides comprises digesting (10) the source material in sulfuric acid (20) to form a slurry, separating (12) a fluoride containing solid phase (39) and a metal containing first liquid phase (26). The solid phase is subjected to pyrohydrolysis (14), sulfuric (40) and hydrofluoric acids (42) are recovered, and the first liquid phase is processed to recover the metal values by solvent extraction (16) or ion exchanges (18). The tantalum values are extracted from the first liquid aqueous phase by a water immiscible organic extractant such as methylisobutyl ketone to form a first liquid organic phase containing tantalum and a second liquid aqueous phase. The tantalum is stripped from the first organic phase using water (33). The process includes the additional steps of heating the separated solid phase from about ambient temperature to an elevated temperature in the presence of water vapor to evolve sulfuric acid (44) and render the gangue chemically inert (52). When the source material contains uranium the digestion step reduces the amount of gangue present in the radioactive source. The process can include the additional steps of removing uranium (34) from the second liquid aqueous phase by either an ion exchange resin or by solvent extraction using a water immiscible organic extractant to yield a uranium depleted aqueous phase (50) which can be treated with an aqueous solution of calcium oxide (66). Sulfuric acid and the organic extractant for extracting uranium can be recycled if desired (20).

Cylindrical metal fibers made from tantalum, columbium, and alloys thereof

Abstract: A method of making a tantalum capacitor of improved specific capacitance (and volumetric efficiency) is described. Short tantalum fibers are precipitated out of a carrier liquid to form a felt, or tumbled to form fiber containing particles, and in either case subsequently bonded so as to form a felt or particles containing the fibers in random orientation in substantially non-aligned array. These particles or felt are heated to bond the fibers together, purify and (optionally) cylindricalize them. The felt or particles can be processed in conventional fashion thereafter to form the capacitor. Cylindricalized fibers and pellets of increased surface area are also described.

Performance carbon blacks

Abstract: Carbon blacks having a CTAB of greater than 155 m2 /g; an I2 No. of greater than 180 mg/g; a N2 SA of greater than 160 m2 /g; a Tint value of greater than 145%; a CDBP of 90-105 cc/100 g; a DBP of 115-140 cc/100 g; a ΔDBP (ΔDBP=DBP-CDBP) of 20-35 cc/100 g; a ΔD50 of less than 40 nm; a Dmode of 40-65 nm; ΔD50/Dmode ratio of 0.55-0.67; and an ASTM Aggregate Volume less than 137,000 (nm)3. Also disclosed are rubber compositions containing the carbon blacks which exhibit superior handling and cornering performance properties, increased abrasion resistance and improved traction.

Process for producing carbon blacks

Abstract: A process for producing carbon blacks without the use of a quenching liquid to stop pyrolysis of the effluent in the reactor. In the process of the present invention, the effluent passes from the reaction zone of a furnace carbon black reactor downstream into a lined wall heat exchanger where the effluent is sufficiently cooled to stop pyrolysis. The effluent may be pre-cooled before it enters the lined wall heat exchanger by a quench injecting fluid at a rate substantially lower than in a conventional process wherein all of the fluid is finely atomized in the effluent such that the duration of the presence of liquid phase in the effluent stream is substantially minimized. In a preferred embodiment a cleaning method is utilized to continuously remove deposits from the interior walls of the lined wall heat exchanger and/or the secondary cooler.

Method and apparatus for separating fine particles

Abstract: A method for separating fine particles from contaminant particles suspended in a gaseous medium. The method includes introducing a particle suspension at a predetermined velocity into a vessel having a top and bottom portion, each portion having a discharge outlet. The particle suspension is then directed into an impingement plate, which is arranged within the vessel at a predetermined angle. The impingement plate is angled to achieve uniform distribution of the particle suspension within the vessel after impact with the plate. The fine particles will rise to the top portion of the vessel, and the contaminant, as well as residual fine particles, will settle to the bottom of the vessel. The fine particles and contaminant and residual fine particles are removed from the top and bottom discharge outlets respectively.

Effect of intermetallic compounds on the properties of tantalum

Abstract: Whereas pure tantalum has excellent corrosion-resistance and form-ability, its high-temperature properties and thermal stability are marginal for some intended applications. Traditional approaches for improving these properties have been dispersion and solid-solution strengthening. Modifications of properties via an intermetallic precipitation was not considered until recently. Results of an on-going investigation on the processing and evaluation of silicide-strengthened tantalum are presented. Yttrium-silicide-containing tantalum samples were produced via the P/M method. Evaluation consisted in microstructural, mechanical, chemical, and functional tests. Results were compared with those of commercially available tantalum. Intermetallics precipitates were found to be very potent in altering these properties. Although the preliminary results are encouraging, extensive functional testing is required to ensure that there is no unexpected adverse effect.

Carbon black containing epdm compositions having either a high gloss or a textured matte finish

Abstract: EPDM compositions comprising EPDM and specified carbon blacks which, when extruded or shaped, exhibit either a highly gloss or a textured matte finish. The carbon black is present in an amount of 100 to about 300, and more preferably about 150 to about 250 parts by weight per 100 parts by weight EPDM.

Effect of Intermetallic Compounds on the Properties of Tantalum

Abstract: While pure tantalum has excellent corrosion resistance and formability, its high temperature properties and thermal stability are marginal for some intended applications. Traditional approaches for improving these properties have been dispersion and solid solution strengthening. Modifications of properties via an intermetallic precipitation was not considered until recently. Results of an on-going investigation on the processing and evaluation of silicide-strengthened tantalum are presented. Yttrium silicide-containing Tantalum samples were produced via the P/M method. Evaluation consisted of microstructural, mechanical, chemical and functional tests. Results were compared with those of commercially available tantalum. Intermetallics precipitates were found to be very potent in altering these properties. While the preliminary results are encouraging, extensive functional testing is required to assure that there is no unexpected adverse effect.

Low ash furnace carbon blacks

Abstract: Novel furnace carbon blacks that impart advantageous properties to rubber and plastic compositions and may be utilized in the place of acetylene blacks. The furnace carbon blacks have an ash level less than or equal to 50 ppm, preferably less than or equal to 30 ppm, most preferably less than or equal to 10 ppm, a sulfur level less than or equal to 50 ppm, preferably less than or equal to to 30 ppm most preferably less than or equal to 10 ppm, an La less than or equal to 30 ANGSTROM and an Lc less than or equal to 30 ANGSTROM . Also disclosed are novel rubber and plastic compositions incorporating the novel furnace carbon blacks which exhibit advantageous properties, particularly in extending the useful service life of power cables produced using the compositions.

Hydrocracking Boscan Heavy Oil with Unimodal and Bimodal Catalysts

Abstract: Publisher Summary Experimental data have shown that diffusion in hydrocracking catalyst pores affects the conversion of heavy oils and bitumens. Other experimental data have shown that conversion can be improved by altering the chemical composition of catalysts that have comparable surface areas and pore dimensions. This indicates that both surface reaction and pore diffusion affect conversion during residuum hydrocracking, although neither controls nor dominates. Bimodal commercial catalysts for hydrocracking residua contain both mesopores (MEP) that provide surface area for reaction and macropores (MAP) that provide large pore cross sections for enhanced diffusion rates. This chapter explains vanadium hydrodemetallization using the catalysts of various pore geometries.