As a new raw material, micro-silica fume is widely used in the refractory industry. It plays an important role in the improvement of monolithic refractories.
Practical applications of microsilica fume in the following areas:
1. Replace pure aluminum niobium oxide as refractory material.
2. As an additive to produce unshaped and shaped refractory products, its strength and high temperature performance are greatly improved.
3. As a pouring and coagulation accelerator for the steel drum as a whole.
4. Cohesive agents, binders, coagulants, and additives for other refractory products.
Application of Microsilica Fume in Concrete
After micro silica fume is mixed into cement concrete, it can well fill the voids of cement particles and make the slurry more dense, mainly manifested in:
1. Increase the strength: greatly increase the compressive and flexural strength of concrete. Adding 5-10% micro-silica fume, the compressive strength can be increased by 10-30%, and the flexural strength can be increased by more than 10%.
2. Increased density: the impermeability is increased by 5-18 times, and the chemical resistance is increased by more than 4 times.
3. Frost resistance: After 300-500 rapid freezing and thawing cycles of silica fume, the relative elastic modulus decreases by 10-20%, while ordinary concrete passes through 25-50 cycles, and the relative elastic modulus decreases to 30-73%.
4. Early strength: Silica fume concrete shortens the induction period and has the characteristics of early strength.
5. The ability to resist abrasion and cavitation erosion is increased by 3-16 times.
Other uses of silica fume:
1. Rubber industry: After adding a certain amount of microsilica fume to rubber, its elongation shrinkage, tear resistance and aging resistance are greatly improved. This rubber also has good dielectric properties and low water absorption capacity.
2. As an anti-caking agent: instead of mica or diatomaceous earth as a raw material to prevent the agglomeration of fertilizer particles.
3. As a binder for pellets: micro-silica fume has a large surface area and strong adsorption, and it has achieved remarkable results as a binder for pellets abroad.
4. Sodium silicate industry: It can replace quartz ore to produce water glass with a modulus of 4.
5. Used as well cementing in oilfields: micro-silica fume is used in major oilfields and has achieved good results.
6. Re-insulation materials, waterproof materials, paint, printing industry, etc. are all used.
Precautions for adding and stirring microsilica fume
1. Usually the concrete industry uses densified silica fume, so manual feeding or automatic feeding can be selected.
2. Due to the unique ultra-fine characteristics of micro-silica fume, micro-silica fume is required to be put in immediately after the aggregate is fed, and powdery micro-silica fume must not be added to the well-mixed concrete.
3. The mixing time of the concrete mixed with silica fume is 30-40s longer than that of ordinary concrete, and the uniformity will be good in the future.
4. There are no special requirements for the transportation of concrete mixed with silica fume, which is the same as that of ordinary concrete. Note that the transportation time should not exceed 10 minutes.