A trigonal soft, greasy and dark-grey mineral, with a metallic sheen and easily flaked. The graphite is a good conductor of electricity and heat, rustproof and acid resistant, which melted only at about 3000 °C and which finds application in many sectors, from electrical engineering to electronic, from metallurgy to chemistry and industry and as protective material for nuclear energy production facilities.

The graphite is also used for the preparation of anti-oxidant varnishes, lubricant blends and for manufacturing pencils together with kaolin.

It is present in metamorphic rocks and it was located in the valleys of Chisone, Pellice, Bormida (Millesimo) in Italy. Today you can find it in other places situated in China, France, Germany and Canada. The artificial graphite is produced by heating at high temperatures carbonaceous material such as anthracite, charcoal and petroleum coke.

Synthetic graphite

The production of the synthetic graphite began at the end of the 19th century, precisely in December 1895, in the USA, when a patent for the carbon graphitization was filed.

The electrographite produced in this manufacturing process was used as electrical current transmission element in the form of electrodes and graphite has since become increasingly important for a wide range of industries and sectors.

The core of the synthetic graphite is made of a very hard carbon part, usually crude petroleum coal, and pitch acting as binder. The two raw material are mixed together to make up a homogeneous mass and then processed and refined in complex processes at high temperature. These processes can vary depending on the desired properties and on the type of synthetic graphite. In this way, a process can be reproduced in a short time, especially when compared to the natural one, which takes million years.

Synthetic graphite morphology

The morphology of the greatest part of the synthetic graphite ranges from flakes of the fine powders to the irregular grains and tips of the coarse products. This technical presentation includes electronic scan micrographs of the morphology of calcined petroleum coke materials to be graphitized, crystalline graphite in flakes, present in nature, and synthetic graphite finely ground.

Manufacturing process of the synthetic graphite

The manufacturing processes of the synthetic graphite require solid raw materials (coke and graphite) to be grounded and mixed with carbonaceous binders, such as pitch, in order to make a homogenous mass before moving to the shaping phase. There are several different processes: isostatic moulding, extruding, vibration moulding or die moulding. Pressed “green” parts are then heated without oxygen to about 1000 °C. During this process, bridging ligands between solid particles are created. Graphitization, the second stage of heat treatment, turns amorphous carbon in three-dimensionally moulded graphite at about 3000°C. Graphitized moulded parts are mechanically turned into complex elements.