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Metallurgical Coke And Asphalt Coke

Release time:2019-11-01 From: Zhengnai Industry in China

Asphalt coke definition

Asphalt coke is a solid combustible product obtained by coking coal tar pitch.Asphalt coke is a high-quality coke with low sulfur and low ash, and it is also an easily graphitizable carbon.


Asphalt coke can be divided into 2 kinds

  • Asphalt coke produced by coke ovens.
  • Delayed coking production of pitch coke.
  • Process of producing pitch coke in coke oven
  • The coke oven produces pitch coke, which belongs to the high-temperature carbonization process. The coal bitumen generates pyrolysis and polycondensation at high temperature, and finally forms coke.

Brief introduction of asphalt coke

  • Raw material for producing pitch coke
  • The raw material for the production of pitch coke in the coke oven can be made of hard asphalt, medium temperature asphalt or soft asphalt as coking raw materials, and the asphalt coke produced by the coke oven has an appearance of iron gray and hard.
  • Delayed coking process The production of pitch coke raw materials is generally soft asphalt or medium temperature asphalt.

Specifications of RP/HP graphite electrode

Item Unit RP HP
300-500mm 550-800mm 300-500mm 550-700mm
Electric resistivity Electrode μΩm 7.5-8.6 7.5-8.8 5.5-6.8 5.5-7.0
Nipple 4.5-6.0 4.0-5.5
Bending strength Electrode Mpa ≥7.5 ≥6.5 ≥10.0 ≥8.5
Nipple ≥16.0 ≥18.0
Elastic modulus Electrode Gpa ≤9.0 ≤13.0
Nipple ≤13.0 ≤15.0
Bulk density Electrode g/cm3 1.54-1.62 1.62-1.70
Nipple 1.70-1.78 1.72-1.80
CTE(100-600℃) Electrode 10-6/℃ 2.20-2.60 1.80-2.20
Nipple 1.50-1.90 1.50-1.80
Ash % ≤0.3 ≤0.3


2 reasons why coke oven production of pitch coke is eliminated

  • The macro hooks of the coke block are not uniform. The coke formed near the fire wall of the carbonization chamber has a high density and a small porosity, and the coke block in the middle of the coke cake has a large porosity and a small density.
  • The pitch coke is produced by a coke oven, and a large amount of harmful gas is generated during the coking process.
  • Characteristics of graphite electrode produced by asphalt needle coke
  • The graphite electrode produced by using the pitch needle coke as a raw material has a relatively low resistivity and linear expansion coefficient after graphitization.


Metallurgical coke use

Metallurgical coke is an auxiliary material for the production of graphite electrodes. It is used as a baking filler, a resistance material for a graphitization furnace, and a thermal insulation material. It is used as a raw material when producing electrode paste and carbon block.

Metallurgical coke definition and morphology

Metallurgical coke is a solid combustible product produced by coking coal after high temperature carbonization. It has metallic luster, generally silver gray, hard and porous, and has many cracks on the surface.


Metallurgical coke description

Metallurgical coke can be divided into 4 categories according to block degree
The metallurgical coke is divided into four categories according to the block size: 1. More than 40mm is called large block coke, 2. More than 25mm is called large middle block coke, 3.25~40tnm is called middle block coke, and 4.25~40tnm is called middle block coke. Or the end of the coke. PS: 10~25mm can also be called small block coke, and less than 10mm is called coke powder.

Metallurgical coke ash content affects coke wear resistance

Metallurgical coke, as a raw material, fuel or reducing agent, hopes that the ash content is as low as possible. If the ash content is too high, the wear resistance of coke is lowered, and the ash content of high quality coke should be no more than 12%.