Selection and influence of particle size of carburizer for calcined coke

One of the key hazards of particle size of carburizer to petroleum coke is the problem of carburization, that is, the high or low digestibility of carburizer. The digestibility of carburizers depends on the comprehensive effect of the external diffusion rate and the air oxidation loss rate of carburizers, and the external diffusion rate and the air oxidation loss rate are the whole process of carburization. The particle size of carburizer is different, so is the diffusion rate and air oxidation loss rate. Petroleum calcined coke

Generally speaking, the particle size of the carburizer is large, the melting speed is relatively slow, and the loss rate is small; the particle size of the carburizer is small, and the total area of the page touching the molten iron is large, the melting speed is faster, and the loss rate is large, so the efficiency of the carburizer will be higher, but the too fine particles will be blown away with the thermal cyclone, and it is very easy for the air to oxidize, so it is difficult to solve the problem Too fine particles should not be used for carburization immediately. Generally, the particle size over mm is more suitable. The particle size limit of carburizing agent is related to the adding opportunity. The particle size of carburizing agent used in the whole smelting process can be moderately relaxed, but the particle size of carburizing agent used before tapping is not suitable for being too large. Tar carburizer

In the smelting process, due to improper proportioning or charging, excessive decarburization, the carbon content of steel can not meet the requirements of peak period, so carbon should be added to the molten steel. The commonly used carburizers are carburized pig iron, electrode powder, petroleum coke powder, charcoal powder and coke powder. Petroleum coke with less impurity is used as carburizing agent when medium and high carbon steel is smelted in converter. The requirements of carburizer are high content of fixed carbon, low content of ash, volatile, sulfur, phosphorus, nitrogen and other impurities, dry, clean and moderate particle size. As the name suggests, the product of carburizing agent manufacturer is to increase the carbon content in hot metal. For example, it is commonly used in smelting furnace charge, pig iron, scrap, return charge and iron with high carbon content, but the purchase price of scrap is higher. Therefore, increasing scrap supply and reducing the quantity of pig iron can reduce the casting cost and play a role.

Application of particle size of carburizer

1. According to the volume of furnace

The selection of particle size of carburizer is closely related to the volume and diameter of furnace. When the diameter and volume of the furnace are large, the particle size of the carburizer is larger; on the contrary, when the diameter and volume of the furnace are small, the particle size of the carburizer is smaller.

2. According to the specifications of the furnace

According to the furnace specification, it is also very important to adopt the appropriate particle size of carburizer. It can reasonably improve the digestion and absorption rate and digestibility of liquid iron. For the induction furnace, the particle size should be 0.2-5 mm, the particle size of 100 kg furnace carburizer should be less than 11 mm, the particle size of 500 kg furnace carburizer should be less than 15 mm, the particle size of 1.5 ton furnace carburizer should be less than 20 mm, and the particle size of 20 ton furnace carburizer should be less than 30 mm.

3. According to the type of workpiece

The particle size of carburizer should also be selected according to the type of workpiece. Among them, the particle size of carburizer for steel and other light metals is 1.4-9.5 mm, while for medium carbon steel, low nitrogen is required, and the particle size is 0.5-5 mm. In fact, these key points must be identified and adopted according to the actual furnace type smelting product workpiece type.

4. Uniform particle size is required

The particle size of carburizing agent should be uniform, and some particles should not be too coarse or too fine. If the particle size is too fine, it is easy to cause air oxidation and ablation of carburizer. If the particle size is too coarse, it floats on the surface of liquid steel and is not easy to be digested and absorbed by liquid steel.