Our company is enterprising manufacture,supply and export of graphite products.

Zhengnai Industry co., LTD

RP|HP|SHP|UHP|Graphite Electrode Suplier

+86 19903830057zhengnaishiye@gmail.com

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Production of graphite electrodes

Release time:2019-11-04 From: Zhengnai Industry in China

The advantages and disadvantages of graphite electrodes .

The quality of graphite electrode mainly depends on the performance of raw materials production equipment and technology, among which the performance of raw materials is the basic condition. The joint quality of high power and ultra-high power graphite electrode is particularly important. The resistivity and linear expansion coefficient of the joint blank must maintain a certain difference with the electrode body. In order to enhance the reliability of the electrode connection, the joint should be equipped with a joint bolt.


Graphite electrode production characteristics

  • 1, the production process is long, the production cycle is long, the production cycle of ordinary power graphite electrode is about 45d, the production cycle of ultra-high power graphite electrode needs more than 75d, and the production cycle of joints requiring multiple impregnation is longer.
  • 2. High energy consumption.
  • 3. There are many processes for producing graphite electrodes.
  • 4. The graphite electrode production process produces a certain amount of dust and harmful gases, so it is necessary to adopt a comprehensive environmental protection measures for ventilation of agricultural dust and elimination of harmful gases.
  • 5. The development of high-power and ultra-high-power graphite electrodes must have high-quality raw materials, mainly needle coke and modified asphalt (binder) and high-quality impregnating agent. Therefore, it is necessary to cooperate with refineries and coking plants.


Production process

  • Calcination.
  • Broken.
  • The kneading.
  • To shape.
  • Roasting.
  • Maceration.
  • Graphitization.
  • Machining.
  • After inspection, the finished products shall be properly packaged and distributed to users.

Ways to reduce oxidation loss on the electrode surface

Reducing the oxidation loss of the outer surface of the electrode is an effective way to reduce the electrode consumption. We have conducted a lot of research on the anti-oxidation coating process of the graphite electrode. At present, the anti-oxidation coating process adopted by several factories at home and abroad is the “alternate spraying-sintering method” of aluminum and refractory materials on the electrode surface.

Index of UHP / HP Graphite electrode

Item Unit UHP HP
300-600mm 650-800mm 300-800mm
Electric resistivity Electrode μΩm 4.8-5.8 4.6-5.8 5.8-6.6
Nipple 3.8-4.5 3.8-4.5 4.2-5.0
Flexural strength Electrode Mpa 10.0-14.0 10.0-14.0 10.0-13.0
Nipple 20.0-26.0 22.0-26.0 18.0-22.0
Elastic modulus Electrode Gpa 9.0-13.0 10.0-14.0 8.0-12.0
Nipple 15.0-18.0 15.0-18.0 14.0-16.0
Bulk density Electrode ≥g/cm3 1.68-1.74 1.70-1.74 1.62-1.66
Nipple 1.77-1.82 1.78-1.84 1.74-1.80
CTE(100-600℃) Electrode x10-6/℃ 1.1-1.4 1.1-1.4 1.6-1.9
Nipple 0.9-1.2 0.9-1.2 1.1-1.4
Ash   0.3 0.3 0.3

Low vacuum, low pressure impregnation production system

Our medium and small diameter products use low vacuum, low pressure impregnation production systems. The impregnation tanks are available in horizontal or vertical type and are generally pressurized with compressed air.

Horizontal high vacuum, high pressure impregnation system

High-vacuum, high-pressure impregnation system adds a secondary tank that uses a water ring-atmospheric jet vacuum pump row and high-pressure nitrogen pressurization to control the pressure in the main tank by manipulating the secondary tank. In addition to the impregnation tank, the auxiliary tank, the vacuum system, and the nitrogen pressurizing device, the system also includes asphalt heating and storage tanks, cooling water pipelines, and flue gas purification equipment.


Semi-continuous high vacuum, high pressure impregnation production system

Semi-continuous impregnation production system is to arrange preheating furnace, impregnation tank and cooling room of impregnated products horizontally on a straight line, add bracket replacement mechanism, and form a “single loop” or “double loop” process, in which the “double loop” impregnation system has higher production efficiency than “single loop”. The impregnating tank is only responsible for impregnation operation. The preheating and cooling of the product after impregnation are carried out in the preheating protection and cooling chamber on both sides of the tank. Because the product bracket is adhering to asphalt in the impregnating tank, special replacement bracket and transfer mechanism are set up. The bracket that does not touch asphalt is only used in the preheating circuit, while the bracket that contacts asphalt is recycled in the impregnation and cooling circuit.

Single tube semi-continuous impregnation production system

The single-tube semi-continuous impregnation production system consists of a heating furnace and a dip tube. This system is more efficient when producing a single specification product, so our company will use this production system when producing specified specifications.