DE1049287B - Process for the production of coal and shaped raphite bodies - Google Patents

Description

Il

GERMAN

35-5

F 23461 IVc / 80 b

REGISTRATION DATE: JULY 13, 1957

NOTICE
THE REGISTRATION
AND ISSUE OF THE
EDITORIAL: 2 2 JANUARY 1 9 5 9

In the known production of carbon and graphite moldings, petroleum or stone tar pitch cokes are used that still contain varying amounts of volatile components. Before processing the coke becomes the material of a calcination at temperatures of 1200 to 1400 ° C subject. The pretreated in this way, by Coke freed from volatile constituents is finely ground with tar, pitch or resins at high temperatures mixed from 25 to 180 ° C and shaped in block, hydraulic extrusion or screw presses. In the subsequent ring furnace fire at temperatures of 800 to 1200 ° C with the exclusion of oxygen cokes the binder and cemented the coke grains into a solid sintered body. Who got so burned Moldings are then, if necessary, graphitized at temperatures of approximately Subjected to 2700 ° C.

In addition to this process for producing carbon and graphite moldings also methods in which under exclusion of Calcin ierungspro zesses the immediate processing of still volatile constituents containing cokes is carried out have been known. According to this procedure, the so-called semi-coke is finely ground with more than 8% volatile components and treated with an organic binder containing hydrocarbons, such as. B tar or pitch, mixed. The resulting "green mass" is then shaped on extrusion or block presses, and the moldings are fired in the usual way with the exclusion of oxygen in a ring furnace at temperatures of 1000 to 1200 ° C and optionally graphitized at temperatures of about 2500 ° C.

The practical implementation of this process is associated with fundamental difficulties. These already begin with the mixing process: When the ground semi-coke is mixed with the binder in liquid form, the components of the mixture are alloyed as the bituminous constituents of the coke react with the binder. This alloying process, once triggered, runs inexorably with the release of a considerable heat of reaction over a short plastic phase leading to a rapid solidification of the mixture, which can then no longer be shaped in the usual way on extrusion or block presses. The duration of the plastic phase is so limited in time that the pressing process cannot be controlled with absolute certainty. The known methods are therefore aimed at lengthening the duration of the plastic phase, ie to delay the alloying process or even to relocate it completely to the firing process in order to ensure the pressability of the green mixture via an appropriate manufacturing process
of carbon and graphite moldings

Applicant:

Farbwerke Hoechst Aktiengesellschaft

formerly Master Lucius & Brüning,

Frankfurt / M., Brüningstr. 45

Dr. Otto Peter
and Dipl.-Chem. Dr. Karl-Wilhelm-Friednch Etzel,

Frankfurt / M.-Griesheim,
have been named as inventors

a period of time. In addition to these processes, mainly the mixing process and the shaping The green mass make it difficult, if not impossible, to occur when firing moldings from non-degassed coke poses additional difficulties. In almost all cases, those after the known suffered Process produced moldings a strong deformation. Their structure is very uneven and interspersed with cracks and larger voids.

It has now been found that the indicated difficulties in the final shaping and in the firing can be avoided and therefore the measures to extend the duration of the plastic phase can be dispensed with if the production of carbon and graphite moldings from petroleum which still contains volatile constituents or coal tar pitch cokes and binders containing hydrocarbons, such as tar or pitch, are carried out in such a way that the coke powder obtained from the cokes by fine grinding is mixed with the binder in liquid form for such a short time, if necessary at an elevated temperature, that the mixture is still plastic Mixture is deformed under pressure as required, the molding solidifying that the molding obtained in this way is ground to a fine powder, the millbase is intimately mixed, if necessary at an elevated temperature, e.g. B. 50 to 200 ° C, and after the final deformation, the moldings are fired and optionally graphitized.

The first deformation is carried out either on an extrusion or block press, with the Crosslinking that has just begun during mixing continues to run unhindered, so that the compact becomes hard.

809 730/366

Claims (3)

The fine millbase obtained after the first shaping is expediently mixed intensively in a dry homogenizer. The second final shaping takes place either on a high-frequency vibrator, possibly one on which two different frequencies act simultaneously, or on a block press. This shaping can now be done without difficulty (e.g. avoidance of cracks, avoidance of bubbles or disintegration of the molding compound), with smooth, dimensionally stable molded bodies being produced. Apparently, the initial pyrolysis only went up to a certain degree of wetting and not to the end, because during this second shaping the material becomes plastic again under pressure and then cross-links again, so that the grains of the powder cement firmly. This comminution and shaping process can be repeated several times, the crosslinking process progressing more slowly and with a decrease in the heat of reaction. The moldings produced in this way are stress-free; After firing and graphitization, they have an extremely homogeneous structure and very good mechanical properties: Fired, graphitized, density 1.68 to 1.701.70 to 1.73 porosity,% approx. 18% 20 to 23 specific resistance, mm2 / m 40 to 508 to 10 compressive strength, kWcm2 1900 600 to 800 flexural strength, kg / cm2 600 to 800 400 to 600 after mixing at 90 ° C in a double bowl kneader with about 25 parts of soft pitch (softening point of 56 ° C) on the extruder. The compacts are ground so finely that all of the ground material passes through the 10,000-mesh sieve, i. H. the maximum grain size is smaller than 0.06 mm. The powder is finally shaped on a block press. The following key figures are determined for the shaped bodies after the ring furnace fire: density 1.56 pore volume 17.8% compressive strength 1922 kg / cm2 Example 2 15 Romanian petroleum coke with a volatile content of 10% and a grain size smaller than 0.15 mm is mixed with 25 parts of soft pitch as in Example 1 and shaped on an extruder and, after cooling, ground to a grain size of less than 0.15 mm. Then it is mixed again briefly in the cold state and plates are produced from this mixture on the block press and the following key figures are determined after graphitization: density 1.71 pore volume 22.8 ° / »compressive strength 667 kg / cm2 flexural strength 509 kg / cm2 specific electrical resistance 9 , 7 ohm · mm2 · irr-1 The above figures for molded bodies produced by the process according to the invention are significantly higher than the values obtained for molded bodies made of semi-coke by the previously known process. Moldings made from semi-coke according to the previous process gave the following values: density 1.65 compressive strength 550 to 650 kg / cm2 flexural strength 250 to 350 kg / cm2 The process according to the invention is particularly suitable for the production of bearing shells and crucibles for melting hard metals and of drawing nozzles for continuous casting processes. Example 1 Non-calcined petroleum coke with a grain size of less than 0.15 mm and 11% volatile constituents becomes P A T Ii N T V N S P R t) C H E 1. Process for the production of carbon and graphite moldings from still volatile constituents containing petroleum or coal tar pitch cokes and containing hydrocarbons Binders, such as tar or pitch, characterized in that that obtained by fine grinding Coke powder with the binder in liquid form, if necessary at an elevated temperature, is mixed as briefly and the still plastic mixture is deformed under pressure as required is then ground the solidified molding to a fine powder, the grist intimately mixed and, after the final deformation, the briquettes are fired and possibly still are graphitized. 2. The method according to claim 1, characterized in that the intimate mixture of the grist ei follows at room temperature. 3. The method according to claim 1, characterized in that the intimate mixture of the grist at elevated temperature, e.g. B. 50 to 200 ° C, takes place. ■ © 809 730/366 1 59