The fluidity of micro silica powder is related to its particle size, specific surface area, chemical composition and whether it is encrypted or not.
Generally speaking, the fluidity of unencrypted micro silica powder can be measured and initially judged by some simple methods. For example: use 40 grams of water, 60 grams of micro silica powder and 0.2 grams of dispersant (such as sodium tripolyphosphate or p530) fully stirred, dumped on a glass plate, natural flow, measure the flow area, if the average diameter is greater than 130mm (also said to be 150mm), it means that the fluidity will generally be very good. However, this method is not very accurate, it is best to also do indeterminate test block test, according to the amount of water added to the final determination of good or bad fluidity.
However, in the case of encrypted micro silica powders, the flowability cannot be measured by the above method and can only be determined by making an indeterminate specimen. Indefinite specimen test has no fixed formula, for example, you can use 70% alumina clinker, 20% 0-325 mesh alumina fine powder, 3% silica fume, 7% alumina cement, sodium hexametaphosphate 0.2% of the formula, and then estimated to add 8-9% of water, and then use the jumping table or shaking table to test the vibration flow value of the castable slurry, the smallest amount of water and the flow value of the largest is usually considered to be a better fluidity.
There may be differences in the flowability of microsilica powders produced by different manufacturers. The smaller the particle size and the larger the specific surface area of the microsilica powder, its flowability may be relatively poor; and the different chemical composition may also affect its interaction with other substances, which in turn affects the flowability. In practice, if you need to know the flowability of microsilica powder, we recommend that you refer to the technical parameters provided by the manufacturer or conduct relevant experimental tests.
In addition, micro silica powder is characterized by high amorphous SiO₂content, low impurity content, high chemical activity, fine particle size and large specific surface area. It can improve many properties of cement-based concrete, mortar and refractory castables, and is widely used in metallurgical pellets, special concrete, special cement, refractory materials, chemical products and other fields.
If you need to buy micro silica powder for a specific project, it is recommended to fully communicate with the supplier to clarify the required flowability and other performance indicators to ensure that the right product is selected. At the same time, it is also necessary to pay attention to the storage and transportation conditions of micro silica powder, which should be stored in a dry, rain-sheltered and sun-shaded environment to prevent it from caking in water and leading to loss of activity.