Contact Person : Will
Phone Number : +8613027622865
March 31, 2020
The technological process of producing magnesia-carbon brick is as follows:
FIG. 1 process flow chart
It can be seen from the process flow chart in FIG. 1 that the production process of magnesia-carbon brick is not complicated, but in order to produce high-quality products, each process must be strictly monitored, among which mixing, molding, heat treatment (drying) these links are particularly important in the production.
Crushing is the process of processing the bulk material into the ideal particle size material.Refractory production is an essential process, although simple, but very important, it has an important impact on the stability of product quality.At the same time, the crushing equipment has high power consumption, high wear and high maintenance rate, so the maintenance cost is high.Attach importance to crushing, stabilize product quality, save energy and reduce consumption.
In the process of producing magnesia-carbon brick, the main purpose of crushing is to prepare various raw materials of different particle size.Increase the material's specific surface area and destroy the material lattice, so that it produces defects, so as to speed up the physical and chemical reaction of the material.
2. Ingredients (weighing)
Batching is the process of combining different raw materials and different particles according to the product formula design.The method of batching varies according to the type and state of the material.
The weight batching method is usually used in the process of producing magnesia-carbon bricks, because the weight batching method is of high accuracy, generally not more than 2%.Commonly used weight batching equipment are manual weighing scale, automatic weighing scale, weighing car, etc., according to the requirements and automatic control level to choose the corresponding equipment.
3. Preparation of sludge (mixing and scouring)
The purpose of mixing materials is to make the material composition uniform, the contact surface between different materials as much as possible.Refractory mixing is a method of homogenizing materials during extrusion, kneading and exhaust process.As with any powder mixing, the mixing of refractory materials is gradually carried out, and because of the material composition, particle size, binder and admixture of different, make the mixing process more complex.
There are many types of magnesia carbon brick, according to its use of different parts, the formula is different, mainly is the taste of magnesia, the amount of graphite added, the type and quantity of additives will change.For example, in the slag line of ladle, in order to improve the slag resistance and thermal shock resistance stability of magnesium-carbon brick, the taste and amount of graphite must be increased.If the carbon content is less than 10%, the continuous carbon network cannot be formed inside the magnesia-carbon brick, and the characteristics of carbon cannot be fully developed, affecting the slag resistance and thermal shock resistance stability of the magnesia-carbon brick.If the carbon content is too high, it will not only bring difficulties to the production of magnesia-carbon brick, but also make it easy to oxidize.So the carbon content of magnesia-carbon brick is generally controlled between 10% and 20%.
In order for magnesia particles to be uniformly coated with graphite, the following steps are generally followed when mixing, first the granule, then the resin, then the graphite, and finally the fine powder and various additives.Graphite density is small, easy to float, and the addition of a large amount, so it is not suitable for mixing, and the addition of additives is very small, so to mix the whole material evenly, must be long time high intensity stirring.However, the binder will volatilize and dry in the stirring process, which will cause the coated graphite and fine powder to fall off. Therefore, the mixing time must be controlled.
Molding is an indispensable process for the production of shaped refractory products. It is a process in which the refractory mortar becomes a blank with certain shape and strength under the joint action of pressure equipment and mold.
Refractory materials have a variety of molding methods, magnesium carbon brick is semi - dry pressing molding.Semi-dry molding is not strict to the mud, the process is simple, in the process of pressure, due to the mud water content is low, must use a large pressure to force the particles between the tight combination.Under the action of external force, the particles are rearranged, the gas is expelled, and the particles combine to produce strength, forming a blank body with a certain shape.The most important factor of semi - dry forming is the applied pressure.With the increase of pressure, the density, porosity and strength increase.
The magnesium carbon brick with good performance has a common character, that is the magnesium carbon brick volume density is big, porosity is low.Open porosity is less than 4% of the magnesia-carbon brick, its erosion rate is very low.
The purpose of forming is to densify the structure of magnesia-carbon brick. Because the forming of magnesia-carbon brick is semi-dry, it must be formed under large pressure.Due to the small size of the mud used for molding, and high graphite content, so the molding should be in strict accordance with the procedures, or prone to crack or layer crack.Should be light after heavy, multiple pressure, light hammer exhaust slowly, heavy hammer pressure slowly lift.
If there is a condition can be used vacuum pumping pressure brick machine, before the pressure of the mold chamber of the mud before the vacuum, pressure when there is no need to exhaust, so even if the speed of the light hammer pressure is accelerated, it will almost not make magnesium carbon brick crack or layer crack.It is especially useful for high carbon magnesium carbon brick which is easy to produce layer cracks.
5. Heat treatment (drying)
The heat treatment of magnesia carbon brick, the factory calls this process normally dry, essentially dry is used in here not quite accurate, because dry basically is to point to the process that contains moisture in the product eduction.The heat treatment process of magnesia-carbon brick not only contains the discharge of water, but also has a series of physical and chemical changes, so we call this process heat treatment.
The heat treatment temperature of magnesia-carbon brick has a direct effect on the properties of magnesia-carbon brick.The heat treatment process of magnesia-carbon brick is actually the process of phenolic resin curing, the heat treatment temperature and heat treatment time directly determine whether the phenolic resin curing completely, in a certain range, the resin curing time and curing temperature is inversely proportional, but not a linear relationship.
Xinyu refractory material through the experimental research shows that the magnesium carbon brick only in a certain temperature range for heat treatment, the density can reach the best, if the heat treatment temperature is lower than the temperature range, the density of the magnesium carbon brick will decline, but if the temperature is higher than the range, the density of the magnesium carbon brick will decline quickly.Repeated studies have shown that the reasonable temperature range is 200℃~250℃.