As the name suggests, graphite blocks refer to graphite blocks. Graphite blocks can be divided into graphite blocks and artificial graphite blocks. Liugong Graphite Manager Xu has been in the business for 20 years, and the most contact is artificial graphite blocks.

Graphite is an allotrope of carbon, a gray-black opaque solid, with a density of 2.25 g/cm3, melting point of 3652°C, and boiling point of 4827°C. Stable chemical properties, corrosion resistance, not easy to react with acids, alkalis, and other chemicals. At 687°C, it burns in oxygen to form carbon dioxide. It can be oxidized by strong oxidants such as concentrated nitric acid and potassium permanganate. It can be used as an anti-wear agent, and lubricant, high-purity graphite is used as a neutron moderator in atomic reactors, and can also be used to manufacture crucibles, electrodes, brushes, dry batteries, graphite fibers, heat exchangers, coolers, electric arc furnaces, Arc lamps, pencil leads, etc.

Graphite is a transitional crystal between atomic crystals, metal crystals, and molecular crystals. In the crystal, carbon atoms in the same layer form covalent bonds through sp2 hybridization, and each carbon atom is connected to three other carbon atoms. Six carbon atoms form a regular hexagonal ring on the same plane and stretch to form a sheet structure. The carbon atoms in the same plane still have p orbitals, overlapping each other to form delocalized π bond electrons, which can move freely in the lattice and be excited, so graphite has a metallic luster and can conduct electricity and heat. Due to the large distance between layers and the small binding force (Van der Waals force), each layer can slide, so the density of graphite is smaller than that of diamond, and it is soft and slippery.

Graphite belongs to the hexagonal system with complete lamellar cleavage. The cleavage plane is mainly composed of molecular bonds and has a weak attraction for molecules, so it is very buoyant.

Due to its structure, LiuGong graphite blocks have the following properties:

(1) High-temperature resistance

The melting point of graphite is 3850±50°C. Even after high-temperature arc combustion, the weight loss is very small, and the thermal expansion coefficient is also very small. The strength of graphite increases with the increase in temperature, and at 2000°C, the strength of graphite doubles.

(2) Electrical and thermal conductivity

The electrical conductivity of graphite is one hundred times higher than that of ordinary non-metallic minerals. Thermal conductivity exceeds that of metal materials such as steel, iron, and lead. Thermal conductivity decreases with increasing temperature, and graphite acts as a thermal insulator even at high temperatures. Graphite conducts electricity because each carbon atom in graphite forms only 3 covalent bonds with other carbon atoms, and each carbon atom retains 1 free electron to transport charge.

(3) Lubricity

The lubricating performance of graphite depends on the size of the graphite flakes, the larger the flakes, the smaller the coefficient of friction and the better the lubricating performance.

(4) Chemical stability

Graphite has good chemical stability at room temperature and is resistant to acids, alkalis, and organic solvents.

(5) Plasticity

Graphite has good toughness and can be ground into very thin flakes.

(6) Thermal shock resistance

When graphite is used at room temperature, it can withstand rapid changes in temperature without damage. When the temperature changes suddenly, the volume of graphite does not change much, and no cracks will occur.

What is the role of graphite block in graphite equipment? Graphite blocks used in producing graphite heat exchangers and graphite absorber equipment are called graphite heat exchange blocks and graphite absorber blocks. Generally speaking, the pores of purchased graphite blocks contain a small amount of water, which needs to be dried first to evaporate the water. This process is carried out in an electric oven, the temperature is controlled within 350 ° C, and the drying time is about 1-2 hours. During drying, water vapor is mainly produced, and no other process waste gas is produced. In the manufacture of graphite heat exchangers, graphite absorber equipment is an integral structure because the heat exchange block and absorption block only bear pressure, without cement joints, high structural strength, and good impact resistance, and occupies an important position in graphite equipment.