Detailed explanation of the production process of refractory bricks
2025-01-17 16:14:13
Refractory bricks, as an important high-temperature resistant material, are widely used in high-temperature industries such as steel, metallurgy, cement, and glass. Its production process involves multiple links from raw material selection to finished product firing, ensuring that refractory bricks can maintain their stability and excellent performance under extreme temperatures and harsh environments. This article will introduce the production process of refractory bricks in detail.
1. Selection and preparation of raw materials
The production of refractory bricks starts with the selection of raw materials. The main components of refractory bricks are minerals with high melting points and good high-temperature resistance. Commonly used raw materials include bauxite, clay, silica, quartz, feldspar, etc. Different types of refractory bricks have different raw material ratios and processing methods.
When selecting raw materials, it is necessary to consider their chemical composition, mineral composition, and particle size distribution. By strictly screening suitable raw materials, it can be ensured that refractory bricks have a stable structure and excellent refractory properties at high temperatures.
2. Crushing and mixing of raw materials
The selected raw materials are crushed and ground to form powders of a certain particle size. For some raw materials that are difficult to process, chemical or physical treatment is also required. In this process, workers mix different types of raw materials precisely according to the designed ratio to ensure that all kinds of raw materials are evenly distributed so that they can obtain ideal physical properties and chemical stability in the subsequent molding process.
3. Molding
Molding is a key process in the production of refractory bricks. There are two main methods: pressing and extrusion.
Pressing: The mixed raw materials are added to the mold and mechanical pressing is used to form a brick. The pressure during the pressing process usually needs to reach hundreds of megapascals to ensure the density and strength of the brick.
Extrusion: For refractory bricks that need to be mass-produced, extrusion molding is a common method. The raw materials are extruded by an extruder to form a brick. Extrusion molding can make the density of the brick more uniform and less prone to cracks.
In the molding process, the design of the mold is crucial to ensure that the size of the brick is accurate and the surface is smooth. The molded brick needs to be demolded and dried.
4. Drying
The molded refractory brick body contains a certain amount of moisture, so it must be dried to remove excess moisture and prevent cracks or breakage during high-temperature firing. The drying process is usually carried out in a dedicated drying kiln, where the temperature gradually rises and the water gradually evaporates. The drying temperature and time should be adjusted according to the thickness and material of the brick. Usually, the drying temperature is between 100-200℃ and the time is generally 24-48 hours.
5. Firing
Firing is the most important link in the production process of refractory bricks, which determines its final physical and chemical properties. The firing process needs to be carried out at high temperature, usually using a kiln for firing. The firing temperature is generally 1300-1600℃, and the specific temperature varies depending on the material and purpose of the brick.
During the firing process, refractory bricks will undergo a series of physical and chemical reactions, such as consolidation of raw materials and transformation of mineral phases. This process can not only improve the strength and density of refractory bricks, but also improve their thermal shock resistance, corrosion resistance and thermal stability. The firing process lasts for several hours or even days, and the temperature rise and fall rate needs to be strictly controlled to avoid deformation or cracking of the bricks during the firing process.
6. Cooling
After firing, refractory bricks need to go through a gradual cooling process. The cooling temperature is usually gradually reduced from 1200℃ to room temperature. During the cooling process, the difference between the thermal stress inside the brick and the external ambient temperature may cause cracks in the brick body. Therefore, the cooling process needs to be carried out in a special cooling device to ensure that the cooling speed is moderate to avoid the generation of cracks.
The strength of the cooled refractory bricks has been further improved, and they also have good thermal stability and impact resistance.
7. Inspection and packaging
The cooled refractory bricks will undergo a series of quality inspections. First, the factory will conduct an appearance inspection to check whether the brick body has defects such as cracks and bubbles; then conduct a dimensional inspection to ensure that the specifications of each brick are consistent; finally, a performance inspection is carried out, including tests of compressive strength, refractory temperature, thermal conductivity and other indicators. Only refractory bricks that have passed strict inspections can enter the next step of packaging.
Qualified refractory bricks will be packaged, usually in wooden boxes, cartons or pallets to ensure that they are not damaged during transportation and storage.
8. Storage and Transportation
The packaged refractory bricks will be stored in the warehouse waiting for shipment. During the storage process, the environment needs to be dry and ventilated to prevent the refractory bricks from getting damp or damaged. Refractory bricks are usually transported by trucks, trains, etc., and delivered according to customer needs.
Summary
The production process of refractory bricks is relatively complicated. From the selection, crushing, mixing of raw materials to molding, drying, firing, and cooling, each link needs to be strictly controlled to ensure that the quality of refractory bricks meets the use requirements. Precise control of each link and efficient production process can not only improve product performance, but also reduce resource waste and energy consumption in the production process. With the development of technology, the production process of refractory bricks will continue to innovate to meet the growing needs of various industries.