DE1193853B - Process for graphitizing coal - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY GERMAN 4WIWt PATENT OFFICE

EDITORIAL

int. α .:

Number:
File number:
Registration date:
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C04b

German class: 80 b -8/10

1193 853
S77610VIb / 80b
January 18, 1962
May 26, 1965

The artificial amorphous coals are made up of various natural or artificial, through a carbonized binding agent joined together carbon bodies, and the bodies obtained in this way have a more or less fine and considerable porosity. The burning of these coals at temperatures over 1800 ° C results in graphitized bodies whose hardness and electrical resistance are very low, however, their frictional properties are improved.

As is well known, the development of carbon into a better crystallized state can be caused by the The presence of various elements, in particular silicon oxide and iron, can be influenced.

The invention is based on the object of providing a method for graphitizing artificial coals create that increase the degree of graphitization and at the same time the mechanical, physical and Improve electrical properties of the products obtained with a view to certain applications leaves. This task is .with the method proposed here for graphitizing carbon mainly achieved in that, according to the invention, a catalyst is introduced into the material to be graphitized which is from the group of rare earths in the form of a salt, an oxide or a Mixture of rare earths, as they occur naturally, is selected.

It has been found that the presence of rare earths, even in a very small weight ratio, more effective than the presence of already known catalysts, such as. B. aluminum, iron, Titanium or vanadium. If one compares the degrees of graphitization at the same graphitization temperature of coals graphitized by the process according to the invention with the same coals, which are impregnated with other already known catalysts, it can be seen that the invention graphitized carbons have a much higher degree of graphitization.

Among the rare earth elements used in accordance with the invention, one preferably chooses cerium, which can easily be introduced into the artificial coals, be it in In the form of a decomposable cerium salt, in the form of cerium oxide or in a mixture with the other elements Rare earths with which it is normally associated.

The catalyst can be mixed with the various components of the powdery charcoal will. However, since its effect on graphitization is important, even if it is Process for graphitizing coal

Applicant:

Societe Le Carbone-Lorraine, Paris

Representative:

Dipl.-Ing. Dipl. Oec. publ. D. Lewinsky,

Patent attorney,

Munich-Pasing, Agnes-Bernauer-Str. 202

Named as inventor:
Jacques Millet, Paris

Claimed priority:

France of January 19, 1961 (850 114)

is in the mixture in a very small amount, it is preferably by impregnating the to graphitizing carbon material introduced.

The following example explains the invention in more detail:

The carbon material is impregnated with an aqueous solution of cerium carbonate and hydrochloric acid. The carbon material to be impregnated can be based on various types of carbon made of petroleum coke or black coals and processed in the form of plates, rods Own pieces. Usually the material is fired at temperatures below 1200 ° C been exposed. The composition of the impregnation solution contains approximately 50 g of cerium carbonate to 0.51 concentrated hydrochloric acid and 0.5 l of water.

The pieces to be impregnated are immersed in the solution using those already known Technique for impregnation under alternating vacuum and pressure. The impregnated parts are pulled out and left to dry. The cerium salt is then decomposed at a temperature of 480 ° C, and when the temperature is increased to 800 ° C, a stable cerium oxide is obtained.

The properties of the impregnated and burned coals at temperatures of around 1800 ° C are compared to those of non-impregnated coals that are burned at the same temperature and otherwise the same completely different. The table below shows the increase in the degree of graphitization for two types impregnated carbon. Grade 1 refers to a coal based on petroleum coke, grade 2

509 577/396

on a coal based on black coal. The degree of graphitization is according to the R. E. Franklin method certainly.

Tempe Variety 1 Variety 1 Variety 2 Variety 2 ratures impregnated impregnated ⁰ C 0 with cerium 0 with cerium 1400 0 0 0 0 1600 - 0.09 0.10 0 1800 0.13 0.12 0.13 0.05 2000 0.35 0.18 0.19 0.07 2200 0.45 0.41 0.19 0.18 2400 0.65 0.72 0.19 0.30 2600 - 0.30

The introduction of small amounts of cerium alone or in admixture with other rare earths into the Pores of the carbon in some form reduce the cost of the graphitization process. With the ao The catalyst proposed here can namely, the degree of graphitization significantly and at lower Increase temperatures, which saves burning costs during manufacture.

Cerium is of course only mentioned here as an example, because every one of the rare earths other element can be used under the same conditions with equally satisfactory results will.

The development of the crystal structure of carbon on the physical, mechanical and electrical properties. The method according to the invention leads to an increase in the degree of graphitization and has the consequence that the graphitized carbons over remarkable Grades in density, wear resistance, electrical and thermal conductivity and with regard to the frictional properties and cover a very wide range of applications. The types of graphitized carbons obtained in accordance with the invention are excellent chemical ones Building materials for heat exchangers, for friction pieces, electrodes, carbon brushes and others.

Claims (6)

Patent claims: 1. Process for graphitizing carbon while increasing the degree of graphitization simultaneous lowering of the graphitization temperature, characterized in that, that a catalyst is introduced into the material to be graphitized, which catalyst is selected from the group of Rare earths in the form of a salt, an oxide, or a mixture of rare earths such as these occur naturally, is selected. 2. The method according to claim 1, characterized in that the catalyst in the artificial Introduced coal in powder or solution form and then treated accordingly is converted into a stable form. 3. The method according to claim 1 or 2, characterized in that the carbon material with impregnated with a solution containing cerium, which is converted into oxide which is stable at 800 ° C and is graphitized at temperatures of 1800 to 2600 ° C. 4. The method according to claim 3, characterized in that the impregnation solution from a cerium salt or an oxide. 5. The method according to claim 3, characterized in that the impregnation solution from a rare earth carbonate and a mixture of water and hydrochloric acid will. 6. The method according to any one of the preceding claims, characterized in that the content of rare earth oxide is between 0 and 10 Vo, preferably 2%. Considered publications:
British Patent No. 542363;
Trans, of the Metal Soc. AIME, 215 (2), pp. 192 to 199 (1959). 509 577/396 5.65 © Bundesdruckerei Berlin