Refractory castables are more common in our daily life. Refractory castables are required in many places, which have good characteristics of high temperature resistance and fire resistance. So do you know how refractory castables are produced? What else do you know about refractory castables? The following is the introduction of "production technology and related knowledge of refractory castables".

【Refractory castable preparation process】

The preparation process of low cement refractory castables is very strict, so there are many factors that affect performance, including ultrafine powder, aluminate cement and additives. Refractory aggregates and additives. The amount of refractory aggregate and water are also important factors.

一 (1) Ultrafine powder

The effect of ultrafine powder on low cement refractory castables has been explained from different angles. The conclusion is that the pillar that determines the performance of low cement series refractory castables can be said without exaggeration. Without ultrafine powder, there is no low Cement series refractory castable.

In low cement refractory castables, ultrafine powders mainly function as dispersion accelerators and structural compactors. The former allows the cement particles to be highly dispersed without flocculation, and the latter has sufficient micropores to improve its strength.

種類 Ultrafine powder types include SiO2, a-Al2O3, Cr2O3, ZrO2 and MgO. The specific surface area of SiO2 ultrafine powder is about 20m2 / g, which has about 1/100 of the cement particles, so it has good dispersibility and filling properties. With the increase of the amount of SiO2 ultrafine powder, the strength increases, and the fire resistance decreases. The appropriate amount is ≥3%.

(II) Aluminate cement

較多 There are many varieties of aluminate cements, and the properties of the formulated low cement refractory castables are different. For example, when the mixing ratio and process conditions are basically the same, the amount of CA-50 cement and CA-70 cement are 5%, and the compressive strength of the dried, 800 ° C and 1100 ° C fired, the former is 45Mpa, 51Mpa and 59Mpa respectively. , The latter corresponding to 65, 70 and 74Mpa. This shows that the performance of low-cement refractory castables formulated with CA-70 cement is better than that of low-cement castables formulated with CA-50 cement, but the cost is slightly increased.

配合 The basic mix of castables remains unchanged, keeping the amount of refractory powder and cement constant. The amount of cement should ensure sufficient room temperature strength to meet the technical requirements for demoulding or lifting of low cement refractory castables. The normal temperature compressive strength of the castable is 15Mpa and 22Mpa, respectively. Before 1100 ° C, the amount of cement was large, and the compressive strength was high after firing. At 1400 ° C and 1500 ° C, the two were basically similar, and the amount of cement was slightly higher.

[Introduction of refractory castables]

如何 How to adhere the refractory castable; whether the high-temperature adhesive is applied evenly and the thickness is moderate during the application. This is very important for the effectiveness of the refractory castable, which is often ignored by operators.

Generally, first apply 1mm ~ 1.5mm thick adhesive on the brick surface with a brush, then apply 1.5mm thick adhesive on the castable material, quickly apply the castable material to the brick surface, and pat it firmly with your hand. You can use round The stick rolled tightly. If the refractory castable is not patted tightly, there will be air bubbles between the felt and the brick. When the oven expands, the air bubbles will expand and the castable will be blown out, and the leak will be gradually leaked.

抹 Applying the adhesive on the castable and the brick at the same time is much better than applying the adhesive on only one side. There are different types of refractory bricks, and the thickness of the adhesive is also different. For rough surface bricks, the adhesive should be thicker, and for smooth surface bricks, the adhesive should be thinner. The binder should not be too thick. If it is too thick, the castable absorbs water and overflows, resulting in soft flaking. Conversely, when it is too thin, the castable is still dry and hard to adhere to the brick surface.

的 The size of the refractory castable is preferably a 600mm × 400mm box. If the proportion is too small, there will be more seams; if the proportion is too large, it will not be easy to stick fast and local leakage will occur. When pasting, do not drive the adjacent block felt that has already been pasted, otherwise it will leak, and you should pay more attention when you have just pasted it. The pasting step is the back wall-stove top-side wall. This is relatively easy to deal with the irregular wall tiles between the back wall and the furnace roof, and between the back wall and the side wall.

Given that the unified plane should be up and down first, and then side up and down, this can prevent the adhesive from dripping on the following fibers. At the mouth of the burner and the exhaust port, the fibers are perpendicular to their surroundings, avoiding that the airflow direction is parallel to the fiber direction, and the casting material is blown away.

The above introductions about "refractory castable preparation technology" and "introduction to refractory castables" hope to help you understand "production process of refractory castables and related knowledge".