Metanoia company has the ability to supply metallurgical coke in the tonnage and conditions requested by respected consumers, due to its extensive communication network with domestic producers, China, India, etc., and the extent of its office in UAE, Iran, etc.

Metallurgical coke

Metallurgical coke is a material with high carbon and few impurities that is used as fuel. Coke is a carbonated solid material obtained from low-ash and low-sulfur bituminous coals.

The coke that comes from coal has a gray color and is also hard and porous. Of course, coke also exists naturally, but the most commonly used coke is coke made from coal by humans.

Special coals are used to produce metallurgical coke, and the properties of the coal determine the properties of the produced coke.

The presence of ash in coke increases the consumption of coke and limestone in the blast furnace and reduces the production capacity of coking batteries.

Coke in the blast furnace has different roles of providing energy and regenerating iron ores and creating porosity for the passage of regenerating gases and carburizing cast iron. Coke is also used in Kopel furnace as a fuel and regenerating agent. It should be noted that coke is also used in casting industries.

Coke has a percentage of sulfur and phosphorus. As a result, the most important factor is the entry of sulfur and phosphorus into the coke steel production process. Sulfur and phosphorus are harmful elements in steel.

Getting to know the coking process

To reduce iron, an agent that separates oxygen from iron oxides is needed. This substance is called a reducing agent. All blast furnace reactions are carried out at high temperatures, which are the result of burning coke.

Coke obtained from coal is used for regeneration and melting in the blast furnace. Natural gas and fuel oil are also used in small quantities instead of coke. In recent researches, it has been shown that the ability to regenerate natural gas hydrogen is much higher than that of coke carbon.

Therefore, it is tried to use the injection of natural gas in the blast furnace to produce hydrogen gas in the blast furnace by burning it. In today’s modern furnaces, the injection method of coal powder is also used, which reduces the consumption of coke. greatly reduces

Because coking coal has low strength and high impurity (approximately 35%), it cannot meet all the necessary conditions as a blast furnace fuel.

Therefore, it turns into coke to find the necessary conditions (sufficient strength and low percentage of impurities and high calorific value) for charging in the blast furnace. Therefore, the changes that result from converting coal to coke are:

  1. Increasing the percentage of carbon and thus increasing the calorific value.
  2. Increasing resistance against mechanical factors such as impact, pressure, falling and wear.
  3. Reduction of volatile impurities resulting from the emission of coal gases and volatile substances
  4. Increasing useful surface area for more burning provided by coke porosity.

In addition to providing the necessary thermal energy in the blast furnace, coke also performs the reduction of iron oxides in iron ore. Regeneration can be done directly by carbon (in front of blast furnace forms) or CO2, H2 gas.

The calorific value of coke should be maximum and its humidity should be minimum.

If the amount of moisture in the coke is high, it has a negative effect on the operation of the blast furnace because it prevents the creation of a suitable thermal condition in the blast furnace and the efficiency of the blast furnace decreases.

By using the dry method, the amount of coke moisture can be reduced and its strength can be increased, and of course, the energy of the gas blown into the coke can also be used.

According to the mentioned cases, the necessary conditions for the coke used in the blast furnace are:

  1. Its calorific value should not be less than 4000 kcal/kg.
  2. The percentage of sulfur should not be more than 1%.
  3. Coke must have sufficient strength.
  4. Its ash percentage should not be less than 14%.
  5. The amount of moisture in coke should be less than 9% and the size of coke grains should be 5-80 mm. Usually, 450-500 kg of coke is needed to melt one ton of raw iron, and the price of this amount of coke is 50-30%. The price of one ton of pig iron.
  6. Volatile substances should be less than 1%.