Process for the manufacture of molded carbon bodies

Claim 2

A process for the manufacture of an anisotropic molded carbon body having a diameter (d) from high-boiling aromatic hydrocarbon fractions derived from coal or mineral oil and having a high coking residue, without an additional binding agent and without using high pressures, comprising filling a mold in the shape of the desired molded carbon body having a diameter of at least 0.1 m with at least one hydrocarbon fraction having a softening point in excess of 40° C. (Kramer Sarnow), said hydrocarbon fraction being in the liquid state or solid state, and heating said fraction without pressure up to 550° C., in a first heating stage until said hydrocarbon is completely converted from the liquid into the solidified stage whereby the crystal structure is oriented by the shear forces of the rising gas bubbles and a needle-like structure is built up, heating in a second heating stage up to approximately 800° C., at a linear heating rate of approximately

Claim 3

2×(1/d 2 )°K./day which is a function of the diameter d in meters of the molded body, and burning the molded body at a temperature of not less than 850° C., removing said body from the mold and graphitizing said molded body.

Claim 4

2×(1/d 2 )°K./day which is a function of the diameter d in meters of the molded body, and burning the molded body at a temperature of not less than 850° C., removing said body from the mold and graphitizing said molded body.

Claim 5

The process as claimed in claim 1, wherein distillation residues derived from coal tar or highly aromatic pyrolysis residues from the steam-cracking of mineral oil fractions are used as hydrocarbon fractions.

Claim 6

The process as claimed in claim 2, wherein the distillation residues have a softening point in excess of 100° C. (Kramer Sarnow) and a content of constituents which do not dissolve in quinoline which does not exceed 1%.

Claim 7

The process as claimed in claims 1 or 2, wherein the molds are manufactured with a shrinkage dimension of approximately 5%.

Claim 8

The process as claimed in claims 1 or 2, wherein the first heating stage up to 550° C. is carried out at a rate as determined by a heating curve defined by the function: T=a×τ.sup.n, in which T denotes the temperature in °C. and τ denotes the time in hours, and a is in the range from 50 to 150, and n is in the range from 0.3 to 0.7.

Claim 9

The process as claimed in claims 1 or 2, wherein the molded body is impregnated, at 300° to 420° C., with a pitch which has a softening point (KS) of 120° to 170° C., in that the heated, molten pitch is poured into the upper, open part of the mold, and penetrates into the molded body solely under the action of gravity.

Claim 10

The product produced by the process of claim 1.

Claim 11

The product produced by the process of claim 6.

Claim 12

The process as claimed in claim 1, wherein the first heating stage is completed in the temperature range up to 550° C. as determined by a heating curve represented by the formula T=a×τ.sup.n wherein T is temperature in °C., τ is time in hours and a ranges from 80 to 100 and n is from 0.5 to 0.6.

Claim 13

The process of claim 1 further comprising impregnating the molded body with pitch prior to burning.

Claim 14

A process for the manufacture of an anisotropic molded carbon body having a diameter (d) from high-boiling aromatic hydrocarbon fractions derived from coal or mineral oil and having a high coking residue, without an additional binding agent and without using high pressures, comprising filling a mold with at least one hydrocarbon fraction having a softening point in excess of 40° C. (Kramer Sarnow), said hydrocarbon fraction being in the liquid state or the milled state, and heating said fraction without pressure up to 550° C. in a first heating stage, said first heating stage being carried out by heating to the temperature below 550° C. at which the formation of the mesophase commences, and then heating at a higher temperature up to 550° C. to produce anisotropically deformable liquid crystals from the isotropic molten pitch, the liquid crystals being mesophase and in a second heating stage rapidly raising the temperature up to about 800° C., at a linear heating rate of approximately 1.2×(1/d.sup.2)°K./day which is a function of the diameter d in meters of the molded body, to solidify the mesophase thereby forming green coke, permitting any gaseous products that were formed in the heating the escape as vapor through the anisotropic mesophase while said mesophase is gradually solidifying, said escaping vapor forming a needlelike texture in the mesophase and burning the molded body at a temperature of not less than 850° C., removing said body from the mold and graphitizing said molded body.

Claim 15

A process for the manufacture of an anisotropic molded carbon body having a diameter (d) from high-boiling aromatic hydrocarbon fractions derived from coal or mineral oil and having a high coking residue, without an additional binding agent and without using high pressures, comprising filling a mold with at least one hydrocarbon fraction having a softening point in excess of 40° C. (Kramer Sarnow), said hydrocarbon fraction being in the liquid state or the milled state, and heating said fraction without pressure up to 550° C. in a first heating stage, said first heating stage being carried out by heating to the temperature below 550° C. at which the formation of the mesophase commences, and then heating at a higher temperature up to 550° C. to produce anisotropically deformable liquid crystals from the isotropic molten pitch, the liquid crystals being mesophase and in a second heating stage rapidly raising the temperature up to about 800° C., at a linear heating rate of approximately 1.2×(1/d.sup.2)°K./day which is a function of the diameter d in meters of the molded body, to solidify the mesophase thereby forming green coke, permitting any gaseous products that were formed in the heating the escape as vapor through the anisotropic mesophase while said mesophase is gradually solidifying, said escaping vapor forming a needlelike texture in the mesophase and burning the molded body at a temperature of not less than 850° C., removing said body from the mold and graphitizing said molded body.