1. Has a high fire resistance

Does not melt or soften. Volatility only occurs at very high temperatures (>3000 ℃). But this temperature cannot be reached in the blast furnace.

2. High compressive strength

Its compressive strength can reach 250-500kg/cm, which is similar to that of clay bricks. But the compressive strength of clay bricks can reach up to 1000kg/cm.

3. The softening point under load is much higher than that of clay bricks. The load softening temperature of general clay bricks is 1400 ℃, while the load softening temperature of carbon bricks does not exist (i.e., the softening point is high), but it must be pointed out that this is only for high-quality carbon bricks with low ash content.

4. The slag resistance is very good. Except for the slag with high FeO content, no slag can play a erosion role.

5. It has high wear resistance, and its wear resistance is not inferior to clay bricks.

6. It is not infiltrated by iron or slag (iron slag cannot adhere to carbon bricks), so there is less chance of nodulation and damage caused by interaction with iron or slag. Therefore, in the past, carbon bricks were used to be laid on the furnace body, which was believed to reduce the chance of nodulation (as furnace nodules are usually generated in the furnace). However, the results showed that if the operation was not normal, there would still be furnace nodules generated.

7. Low expansion coefficient. This is one of the characteristics of carbon bricks, and other refractory materials are far inferior to it. Under high temperatures, rapid cooling does not produce cracks, which is a highly necessary property for certain parts that are prone to cracking and damage (such as the furnace bottom). Therefore, carbon bricks are often used to build furnace bottom bricks.

8. The thermal conductivity is much higher than clay bricks, especially graphite bricks. But its effects may be beneficial or harmful. A large heat loss is a negative effect, but it is advantageous for slag to form in the lower part. When the lower part of the blast furnace is built with carbon bricks, it can be Free cooling only with air instead of cooling water, and even some smaller blast furnace hearth does not need cooling at all. But generally, cooling water tanks are still used because sometimes the quality of carbon bricks is poor and the furnace hearth is easily damaged. Without a cooling water tank, iron slag leakage accidents can occur. At the same time, installing a cooling water tank is not very troublesome. Therefore, cooling water tanks are still used when using carbon bricks.

Carbon bricks are generally manufactured by grinding coke with little ash (<10mm) into very small particle size, adding 16-18% coal tar to mix evenly, crushing to 6mm at the same time, and then forming under pressure, which also reduces the porosity. It is baked in a sealed furnace for days and nights at 1000 ℃. There should be no air gaps in this furnace; During roasting, sand is used to cover the brick shape, completely isolating the brick from the air and heating the brick by conduction. The high fuel consumption and low production are the reasons for the high price of carbon bricks.