What are the molding processes of insulating refractory bricks

Insulating refractory bricks play a vital role in the high-temperature industrial field, and their molding process is a key link in determining product quality and performance. The choice of molding process not only affects the structural stability and thermal insulation performance of the product, but is also directly related to production efficiency and cost control. Therefore, understanding the characteristics and applicable scope of different molding methods is of great significance for improving product competitiveness.

Slurry injection molding technology
Slurry injection molding is an efficient molding process suitable for thin-walled hollow products. This method injects mud into a gypsum mold, and uses the water absorption characteristics of gypsum to gradually absorb the moisture in the mud to form a relatively dry mud film. As time goes by, the mud film continues to thicken and eventually reaches the required green body thickness. At this time, pour out the excess mud in the mold, and demold, dry and repair the green body after it reaches a certain strength. The moisture content of the mud for slurry injection molding is usually between 35% and 45%, and is widely used in the production of thin-walled hollow products such as thermocouple sleeves, high-temperature furnace tubes and crucibles. This process can effectively improve production efficiency and reduce costs while ensuring product quality.

Plastic molding (extrusion molding)
Plastic molding, also known as extrusion molding, is mainly used to produce strip and tube-shaped blanks. This process uses plastic clay with a water content of 16% to 25%, and uses a continuous spiral extruder or a blade mixer in conjunction with a hydraulic press to mix, extrude and mold the clay. During the extrusion molding process, the clay passes through the die hole under strong pressure to form a blank with a uniform cross-section. This molding method has the advantages of high production efficiency, stable blank size and good surface finish, and is particularly suitable for producing strip and tube-shaped refractory products with uniform cross-sections.

Machine compression molding technology
Machine compression molding, also knwn as semi-dry molding, uses clay with a water content of about 2% to 7% to prepare the blank. This process is molded by various brick presses, tamping machines and vibration machines. Compared with plastic molding, the blank produced by machine compression molding has higher density and strength, less shrinkage during drying and firing, and the product size is easy to control. Machine pressing is one of the commonly used forming methods in refractory production, and is widely used in the production of advanced refractory materials such as fused corundum, mullite and zirconium corundum.
In machine pressing, it can also be subdivided into a variety of specific forming methods to meet different production needs. Friction brick press uses the friction wheel to drive the slider to move up and down through the lead screw to press the mud. The equipment has a simple structure, is easy to operate and maintain, and has strong adaptability. It is a forming equipment that is widely used in refractory production. Hydraulic brick press generates static pressure through liquid energy transfer, works smoothly, double-sided pressurization, and is easy to adjust the pressure. It can meet the requirements of refractory product forming process and ensure the quality of pressed bricks. High-performance hydraulic brick presses are also equipped with vacuum degassing function, which is suitable for forming a variety of refractory products, such as large converter lining bricks and carbon-containing special products.
Lever brick press uses a mechanical lever structure to perform double-sided pressurization in a fixed mold. Its punch stroke value is constant, which is suitable for the production of a variety of refractory bricks. This molding method has the advantages of flexible operation and high production efficiency, and is one of the indispensable molding technologies in the field of refractory materials.