How To Choose Suitable Micro Silica Powder (Silica Fume) To Improve The Performance Of Refractories?

1. Silicon dioxide content:

The silicon dioxide content in micro silica powder is usually high, and you should choose the product whose silicon dioxide content meets the requirements. Generally speaking, the higher the silica content, the more obvious its role in refractories may be.

2. fineness and specific surface area:

Fineness less than 1μm particles accounted for a high proportion of small average particle size (such as 0.1 ~ 0.3μm) and large specific surface area (such as 20 ~ 28m ² / g) of the micro-silica powder, has a better filling effect, can be filled with refractory materials in the tiny pores, to improve the material's densification.

3. Activity:

More active micro silica powders react more actively with other components, e.g. in the presence of alumina, and are more likely to produce mullite phases that contribute to refractory properties. Activity can be assessed by understanding its production process and source.

4. Physical properties:

Good quality micro silica powder has a uniform color appearance, usually gray or off-white, and should not have a high number of brownish-black particles; it should not have a pungent or other offensive odor; and it has good flowability, which contributes to its uniform distribution in refractory materials.

5. Chemical composition:

In addition to focusing on the silica content, it is also important to understand the content of other chemical components, such as calcium oxide and other components, which may affect the performance of the micro silica powder and its reaction with other components in the refractory material.

6. Stability of quality:

Choose a supplier of micro silica powder with stable quality to ensure that the performance of the products purchased each time is consistent. You can check the supplier's production management, quality control system and relevant quality certificates.

7. Actual application effect:

If possible, you can refer to the actual application cases and effects of the micro silica powder in similar refractories to understand its performance in actual use.

8. Particle size distribution:

Narrow and suitable particle size distribution can help to improve the performance of micro silica powder in refractory materials.

9. zirconium content (if necessary):

zirconium-containing micro silica powder silica fume has some special properties, such as zirconium-containing micro silica powder silica fume has high SiO₂ content, fine particle size, large specific surface area, good fluidity and other characteristics, which can improve the fluidity of the refractory castable material; high refractoriness, which ensures that the performance of the refractory material is stable at high temperature; it also improves the mechanical properties of the refractory material, and the high activity of silica components in it is easier to react with alumina to form Moxa. It is easier to react with alumina to generate mullite phase, which improves the high-temperature strength, thermal shock and creep resistance of refractory materials. If there are specific performance requirements for refractories (such as higher high temperature stability, strength, etc.), you can consider choosing zirconium-containing micro silica powder silica fume, but it should be noted that its chemical composition, particle size and other indicators should also meet the requirements.

When selecting micro silica powder, it is recommended to carry out small-scale experiments and tests first to evaluate the impact of different micro silica powders on the material performance according to the specific requirements and performance indexes of the refractory material, so as to determine the most suitable type and dosing amount of micro silica powder. It is also advisable to consult professional refractory engineers or relevant technical experts for more accurate and detailed advice.