DE817269C - Manufacture of carbon molded pieces from pitch - Google Patents

Description

The present invention relates to improvements in the manufacture of shaped Carbon products made from pitch.

When distilling certain bituminous materials, namely coal tar, petroleum or asphalt, valuable volatile substances are distilled off, while a solid or viscous residue remains, hereinafter referred to as pitch.

In a proposal that does not belong to the state of the art, a method is described according to which such bituminous materials are treated in two operations, the primary and secondary Operation are designated.

Here (see the drawing of the operations) the primary operation includes the following Levels: i. Distillation of the starting material, the pitch remaining as a residue, 2. Dissolving the Residue in a volatile solvent and

3. Separation of the solids from the solution, ao z. B. by filtering or centrifuging, with freer Carbon is deposited while the liquid pitch filtrate the solvent and the dissolved Contains bad luck.

In this primary process, the as primary free carbon carries the greater part of the mineral constituents which are in the original Starting material are included. The proportion of mineral substances can be quite low but it will always be higher than the proportion that we used for the range below Consider the expression "essentially free of mineral constituents" to be permissible.

The solvent can be removed from the pitch filtrate by distillation, with a secondary Tar remains, which recently in the secondary process just like the original Starting material subjected to distillation

can be. Optionally, the removal of the solvent from the pitch filtrate and the Distillation of the secondary tar can be summarized in a fractional distillation, however it is more appropriate for the present purposes to do a secondary operation with the to start secondary tar, this operation again comprising the following stages: i. Distillation leaving a

ίο residue of secondary pitch, 2. dissolving of the secondary pitch in a volatile solvent; and 3. solid matter separation from solution, e.g. B. by filtering or centrifuging, whereby free carbon is deposited becomes, while a secondary pitch filtrate the solvent and the dissolved pitch contains. The solvent can in turn be removed from this secondary pitch filtrate, wot > a tertiary tar remains, which can then go through a tertiary operation; so Several such successive approaches can take place. We find that the secondary free carbon is essentially free of mineral substances and is freer Carbon from successive operations is similarly free from mineral Fabrics is.

In the secondary process, the secondary free carbon is deposited from the pitch solution becomes, essentially free of mineral constituents, by which we mean that the proportion of mineral constituents, if any, is always lower than that of the primary free carbon.

Object and object of the present invention]> e refers to either the primary free Carbon or the secondary free carbon that is produced by mineral components in the is essentially free and that from the secondary or any of the following operations of the in the aforementioned. Patent description stems from the process for the production of shaped To make carbon products usable. The value of carbon for purposes of Thermal engineering, chemistry and electrical engineering are recognized more and more. Can also be said be that the demand for an essentially pure and hard, non-graphitic Carbon is constantly increasing. It is of course well known that essentially pure coals can be produced by the process of electrographitization. However, there are certain Not to mention uses for which a hard, non-graphitic carbon is preferable from their lower production costs. It is not our intention to generate graphitic Coal, which in certain cases may be necessary or desirable, from the present invention exclude, but the method of the present invention mainly relates to the Manufacture of hard, non-graphitic carbon.

According to the present invention, free carbon, which arises from pitch, or a mixture in which such free carbon predominates, is brought into the desired shape and the shaped piece is then ^{heated in a non-oxidizing atmosphere to a temperature not below 550 °} C., the The temperature rises rapidly, but not so rapidly that, as a result, puffing or swelling occurs.

Various finely divided, solid or liquid substances can be added to the free carbon will; Their job is to prevent bloating at a given rate of heating or to promote caking or flowability of the mixture in the molding process to increase or to give special properties to the molded piece. Some examples such substances that prevent swelling are: low-baking charcoal, silica, graphite, Hydrochloric acid, alcoholic iodine solution.

Those commonly used in the coal industry can be used to promote caking Use binding agent.

During the molding process, the body is given the desired shape and dimensions before heating and furthermore sufficient cohesion so that the body can be placed in an oven undamaged can be.

If the traces of solvent left in the free carbon are not before molding have been removed, the fitting must be heated very slowly until the solvent has evaporated. By and large, it is preferable to remove the traces of solvent prior to use Remove shapes for which purpose any of the usual methods can be used.

With regard to the heating stage, we have generally found that, all other things being equal, a rapid increase in temperature gives more solid products than are obtained with slow heating. Preferably, the rate of temperature rise is the maximum at which swelling is still avoided under the particular conditions and relationships of each furnace charge. Pipe fittings, which have for many purposes good strength properties can be obtained, if one continues heating up to 850 ⁰ C. If it is desired to produce a material for electrographitization, it is advantageous to heat it up to final temperatures of 1200 to 1400 ^° C. Means for achieving the necessary non-oxidizing atmosphere are well known in the relevant technology.

The following example illustrates one way of carrying out the invention, with the specified parts are parts by weight.

Embodiment

8 g of free carbon from the secondary operation, obtained by the method described above from raw coal tar pitch with a melting point of 115 ^° C., were poured into a steel mold of 2 ¹ /., "(Approx. 64 mm) length X ¹ Z ₂ " ( approx. 12.7 mm) width and placed in a hydraulic press under a

Pressure of 41 per square inch (approx. 635 atm.) Formed into a rod with the dimensions 2V ₂ "X W X ¹ A" (approx. 64 X 12.7 X 6.35 mm). The rod was placed on a metal sheet in an electric furnace and the temperature in the furnace was ^{increased to 850 ° C. with a temperature increase of Va 0} C per minute, the non-oxidizing atmosphere being formed by a stream of oxygen-free nitrogen. After cooling to about 2oo ^c C, the sheet was taken out from the oven. The carbon rod was firm and not warped. Compared to the molded unheated rod, the weight loss was 13% and the linear shrinkage (shrinkage) was 14%.

Claims (4)

PATENT CLAIMS: 1. A process for the production of shaped coal pieces from pitch, characterized in that the Pechrüekstaud from the distillation of bituminous material, namely coal tar, petroleum or asphalt, in a solvent, such as. B. Solvent naphtha, is dissolved, the solid components, z. B. by filtration or centrifugation, whereby primary free carbon is deposited, while the liquid pitch filtrate contains the solvent and the dissolved pitch, the solvent is removed by distillation, the secondary tar is distilled to leave a residue of secondary pitch , the secondary pitch mixed with a solvent and the solid components, e.g. B. by filtration or spinning, separated secondary free carbon, and finally the free carbon is brought into the desired shape and the molded piece is heated ^{to a temperature not below 550 0 C in a non-oxidizing atmosphere} keeping the temperature rise fast but not so fast that it would cause swelling. 2. The method according to claim 1, characterized in that that primary free carbon is used to shape the pieces. 3. The method according to claim 1, characterized in that that secondary free carbon is used for molding. 4. The method according to any one of the preceding claims, characterized in, that the free carbon is treated with an agent that prevents swelling before molding, z. B. low-baking coal, silica, graphite, hydrochloric acid, alcoholic iodine solution or the like., is mixed. 1 sheet of drawings 1813 10:51