Treatment of waste magnesia-carbon bricks and matters needing attention for recycling
In recent years, the demand of magnesia-carbon refractory is very large, after the use of magnesia-carbon bricks are treated as industrial waste before, not only waste resources and pollution of the environment. With the increasing shortage of magnesium resources, the product market atmosphere is less and less ideal, so it is more and more important to control the production cost of magnesium carbon brick. The used magnesia-carbon brick is recycled into raw materials, which are called magnesia-carbon brick re-raw material or re-raw material for short. The used magnesia-carbon brick is called waste magnesia-carbon brick. It is one of the feasible methods to reduce production cost to introduce recycled materials into magnesia carbon brick.
Due to the wide range of magnesia-carbon bricks, there are many sources of waste magnesia-carbon bricks. It can be roughly divided into converter residual after use, electric furnace residual after use and ladle residual after use. Because each steel mill smelting conditions are not the same, the production of steel is not the same, so the magnesium carbon brick formula is very different, the residual magnesium carbon brick is uneven, so how to identify the quality of waste magnesium carbon brick is very critical, is the most important part of the process of raw material selection.
Magnesia-carbon brick in the use of harsh and complex conditions, in the use of the process of a variety of physical and chemical changes occurred in the process of use, in order to make waste magnesia-carbon brick particle material performance problems, must be pre-treated.
At present, the most commonly used method is hydration treatment, the waste magnesia-carbon brick will be broken and iron removed after soaking in water, and then drying to less than 0.5% of the water can be, after drying, if the conditions permit, can be used in the mixing mill grinding weight for rolling, crushing false particles, and finally iron removal, screening, bagging for use.
There are many methods of hydration treatment, such as soaking method, water vapor method, accumulation of water cover film method and so on. One of the pool soaking method used the most. The soaking time is related to the water temperature. In order to fully hydrate the harmful impurities, according to the temperature change of spring, summer, autumn and winter, the following soaking time regulations are formulated. From the practical operation, the effect is very good.
The re-raw materials after hydration need to be dried. At present, the investment is less and the operation is simple rotary kiln, as shown in figure 1.
This kiln has low production cost, high production efficiency and large output. Because the dust is big when the raw material is dry, must do a good job in environmental protection, after the drying of the raw material must regularly sample and test the moisture, ensure the quality is stable.
First of all, there are many kinds of re-raw materials, so when using re-raw materials must distinguish between the types and grades of re-raw materials, classification use. Secondly, due to the large number of false particles and large pores in the recycled materials, the amount of resin added should be increased. According to the experiment, we obtained the following data:
As the actual production of raw materials in the maximum proportion of 60%, so more than 60% of the data to be determined.
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