PRODUCTION OF CARBON BLACK

Abstract: The application of pure carbon produced on the basis of natural gas or methane as especially adapted admixture materials for the rubber industry, for pigment and printer's ink, as a reduction material for the metallurgical industry, as an anode material for aluminium production, and as a decarburizing material for the steel industry.

Description: Production of carbon black The invention relates to the production of carbon black in a pure form based on natural gas or methane. Decomposition of hydrocarbons for the production of carbon black is a well known process and there are a number of methods in existence for this purpose. The production of carbon black on the basis of methane is also described in Norwegian patent application No. 91 4904 by the same applicant. In the method which is described in this application, it has been shown that it is possible to decompose hydrocarbons in such a way that the physical properties of the carbon black to a great extent can be predetermined on the basis of given process parameters. This has proved to be an extremely valuable possibility which can open the way for wider areas of application and for the achievement of better quality for products in which carbon black is already in use as the basic material. There has been a need to find new applications for natural gas, since those resources which have been established are very substantial. The replacement of some of to-day's products with natural gas could provide major environmental benefits. Methane is a i drocarbon gas which exists in large quantities, is reasonably priced and has been shown to be well suited as a stock material for the production of pure carbon black and hydrogen. Moreover, insufficient attention has been paid to the possibility and the significance of the use of pure carbon black as the basic material for final products. Thus the object of the present invention is to provide new methods for the application of methane and especially of pure carbon black. A further object of the invention is to provide opportunities for the application of these materials in the 2 form of basic materials which are both financially favourable and also afford improved quality. These objects are achieved by the application of pure carbon black and hydrogen which are produced by the decomposition of natural gas or methane into their basic elements for the production of admixtures for the rubber industry, as pigments and printer's ink, for battery production, as a reduction material in the metallurgical industry, as an anode material in aluminium production, a carburizing material for the steel industry, activated charcoal, etc. The surprising fact has been demonstrated that on the basis of natural gas or methane which are decomposed into their basic elements, viz. carbon black and hydrogen, carbonaceous mater¬ ials in particular can be obtained in which the properties of the carbon, i.e. its specific weight, particle size, surface, characteristics, porosity and structure can be preset before production in such a manner that the end product obtained is specially suited to the particular above-mentioned purposes. The use of natural gas as a starting material provides a reasonably priced carbon black with special properties for special purposes and it has been shown that by means of the special application according to the invention, electrodes, admixtures, etc. are obtained with particularly favourable properties, as, e.g., in the aluminium industry or in the metallurgical industry, and a far more pollution-free produc¬ tion process is obtained. In the production of activated charcoal it has been shown that by means of the invention a material can be obtained with substantially better adsorption properties than with the activated charcoal used hereto, based on traditional raw materials such as wood, pit coal, lignite, peat, coconut shells, etc. In this process it is also possible to control the activated charcoal's adsorption properties by varying the surface pore size. The application possibilities which have emerged as a result of the invention have proved to be very surprising. By using the indicated starting products, natural gas or methane, and exploiting the possibilities provided by this special starting material, with the possibilities which have emerged for adjusting the physical properties of the carbon formed, the surprising result has been obtained that the application for the said purposes has provided a marked improvement in the final product and has given the final producer considerably greater scope for obtaining special product qualities. In the rubber industry, e.g., the application of carbon black according to the invention has made it possible to produce rubber qualities with exceptional elasticity and rebound resilience. For activated charcoal, qualities can be provided whose absorption capacity is perfectly adapted to the purpose. As an electrode material the invention makes it possible to produce exceptionally pure electrodes at a reasonable cost, thus largely avoiding pollution from foreign materials. In a further advantageous embodiment of the invention it will also be possible in the case of the special applications to use admixtures which may be favourable in the particular context. Thus the invention provides a number of new product possibil¬ ities in the indicated area where polluted carbon can be replaced with a completely pure carbon with corresponding or better properties. The invention will now be described in more detail by means of some examples of the application. Example 1 In the application of carbon black produced by means of decom¬ position of methane, the carbon quality was selected and adjusted during the production process for use in the produc- tion of rubber for car tyres and for technical rubber. The selected values are presented in the following table. RUBBER BET DBP) ASTM m 2 /g ml/100 classification Car tyres 20-200 65-200 N110-N660 Tech. rubber 5-80 40-150 N550-N990 BET: "Brunauer, Emmet &. Telfer" method. DBP: ASTM D-2414 "Carbon Black Dibuthyl Phtalate Absorption". Classification: ASTM D-1765 "Carbon Black used in rubber products". The carbon black covers the entire quality range for the rubber industr . Example 2 A pure carbon produced from methane is used as pigment/ print¬ er's ink after having been provided with the following physical properties. PIGMENT/PRINTER'S INK BET DBP Tint strength pH m 2 /g ml/100 g 20-N500 30-150 20-130 3-9 Tint strength: ASTM D-3265 "Test Method for Carbon Black - Tint Strength". Covers the entire quality range. Example 3 The carbon black according to the invention was used for the production of dry batteries with the following quality specifi¬ cation. 40-80 20-50 < 0.1 (200 bar) AS: "Adsorption rigidity", i.e. admixture of acetone solution necessary in order to be able to shake the powder into a ball (ml/5 g powder), method "Knapsack". Covers the quality "Acetylene Black". Example 4 The carbon black was used according to the invention with the following quality characteristics. REDUCTION MATERIAL FOR THE METALLURGICAL INDUSTRY BET DBP Spec. el. resistance Reactivity m 2 /g (ml/100 g) ohm cm (ml SiO) 5-30 30-200 < 0.1 250-1000 Reactivity: J. Kr. Tuset and O. Raaness: "Reactivity of Reduction Materials in the Production of Silicon, Silicon-rich Ferro Alloys and Silicon-Carbide'" AIME El. Furnace Com., St. Louis, Miss. 7-10 December 1976. 6 Modification of the particle structure is necessary. Carbon particles with .crystalline form and good conductivity are used. The carbon black has to undergo a finishing treatment by the admixture of " a binding agent of the molasses type, bitumens and alternative resins in order to achieve high strength at a high temperature to enable it to be produced in the required product form (briquette/agglomerate with an "open structure") . Necessary properties in the product: Reactivity: High degree of reactivity, i.e. open structure. < 1000 ml/SiO (Sintef method) . Mechanical strength: "Great", should be capable of withstanding load in furnace charge at high temperature without clogging. Example 5 Application as anode material for aluminium production. ANODE MATERIAL FOR ALUMINIUM PRODUCTION BET DBP Spec, weight compressed Spec. el. resistance m 2 /g ml/100 g g/cm 3 ohm cm < 5 < 30 1.5-1.7 < 0.1 Requirements for the carbon black: - "No" structure, i.e. quality "heavier" than N-990. High degree of graphitization provides carbon particles with crystalline form/good conductivity. Little reactivity (little open porosity) . Carbon black with binding agent is given a finishing treatment to produce the correct produpt form ("coke" ,' briquette, ag¬ glomerate wi€E "dense" structure) . Requirements for produced anode material: Density: 1.5 - 1.6 g/cm 3 Spec. el. conductivity: 30-60 ohm m Compressive strength: approximately 45 MPa Tot. porosity: approximately 30% Example 6 CARBURIZING MATERIAL FOR THE STEEL INDUSTRY BET DBP Spec. el. resistance H m 2 /g ml/100 g ohm cm ppm 5-30 30-200 < 0.1 < 200 Requirements for the carbon black: The carbon black must be "reactive", i.e. in this connection suitable for rapid dissolution in the material as C-atoms. The proportion of hydrogen must be low, otherwise hydrogen "blisters" are formed. Example 7 ACTIVATED CHARCOAL BET DBP m 2 /g ml/100 g 5-50 30-200 The carbon .black with binding agent is given a finishing 8 treatment to produce the required product form (agglomerate/ex¬ truded form) with subsequent activation. Requirements for activated charcoal: BET Pore dia. m 2 /g & 500-1500 10-100 (*) * depending on the application (i.e. type of molecule to be adsorbed) . Example 8 In modifying the reactor atmosphere, i.e. admixture of e.g. an oxidizing medium such as 0 2 , air, H2O, C0 2 or other medium, the carbon's physical properties such as BET, DBP, pH and particle form are controlled both individually and mutually to achieve the required value.

Claims: PATENT CLAIMS 1. Pure carbon black in the form of carbon particles, produced on the basis of pyrolytic decomposition of natural gas and/or methane, where natural gas and/or methane are decomposed into carbon black and hydrogen and where hydrogen may be recycled and used as a plasma-forming gas in the process, characterized in that the carbon black is a specially defined material with regard to particle size, structure, surface, specific weight, degree of acidity, electrical conductivity, reactivity, etc. for the preparation of special properties for products and/or the creation of special products, particularly within the metallurgical industry. 2. Carbon black as described in claim 1, characterized in that it is produced on the basis of natural gas and/or methane as specially adapted active coal. 3. Carbon black as described in one of the preceding claims, characterized in that it is specially suited for use as a reduction material, anode material, carburizing material or lining material within the metallurgical industry. 4. Carbon black as described in one of the preceding claims, characterized in that it has a surface area (BET) of 5-30 m 2 /g, a dibutyl phthalate absorption (DBP) of 30-200 ml/100 g and a specific electrical resistance of less than 0.1 ohm cm. 5. The application of pure carbon black in the form of carbon particles, produced on the basis of pyrolytic decomposition of natural gas and/or methane in a plasma reactor where natural gas and/or methane are decomposed into carbon black and hydro¬ gen and where hydrogen may be recycled and used as plasma- forming gas in the process in the form of a specially defined material with regard to particle size, structure, surface, specific weight, degree of acidity, electrical conductivity, reactivity, etc.. for the preparation of special properties for products and/or the creation of special products within the metallurgical industry. 6. The application as described in claim 5 of pure carbon black produced on the basis of natural gas and/or methane, as specially adapted active coal. 7. The application as described in one of the claims 5-6, where the carbon black is used as a reduction material, anode material, decarburizing material or lining material within the metallurgical industry. 8. The application as described in one of the claims 5-7, where an additive is used together with the carbon black. 9. The application as described in one of the claims 5-8, where the carbon black has a surface area (BET) of 5-30 m 2 /g, a dibutyl phthalate absorption (DBP) of 30-200 ml/100 g and a specific electrical resistance of less than 0.1 ohm cm.

Inventors: HOX KETIL, HUGDAHL JAN, LYNUM STEINAR, HOX, KETIL, HUGDAHL, JAN, LYNUM, STEINAR
Applicants: HOX KETIL, HUGDAHL JAN, KVAERNER ENG, LYNUM STEINAR, KVAERNER ENGINEERING A.S
Application year: 1993
Main classification: C09C1
IPC codes: C01B31, C09C1