What are densified silica fume and silica fume slurry products? How is it different from ordinary silica fume?

      The silica fume obtained by direct dust collection is called “original silica fume” or “common silica fume”, with an accumulation density of only 150-200kg/m3, which is very easy to fly and form dust during transportation, and the transportation efficiency is very low, and it is also not suitable for pneumatic or spiral transportation, because loose and small silica fume particles are very easy to be adsorbed on the pipe wall and form arches, which will cause blockage. It is also not suitable for pneumatic or screw conveying, because the loose and tiny silica fume particles are easily adsorbed on the pipe wall and become arches and clogging occurs. In order to overcome these shortcomings of the original form of silica fume, the use of densification technology under the action of the air flow to make individual silica fume particles collide with each other and rolling aggregation, to become a van der Waals cohesion of the diameter of the small particles of 0.1 ~ 1.5mm, thus increasing the density of silica fume accumulation to 500 ~ 700kg / m3, i.e., 'densified silica fume'. In this way, the silica fume is not only able to be transported over long distances more economically; its own mobility is also greatly improved, and it can be adapted to the methods and equipment for conveying cement and fly ash, which makes it convenient to use. Densification of silica fume small particle mass cohesion is weak, in the concrete production of forced mixer mixing process by the impact of gravel is easily dispersed in the concrete mix.

      For cement mortar (dry mortar), the mixing process lacks the strong impact of coarse aggregate, grinding effect. In order to ensure good dispersion of densified silica fume in mortar, and to avoid the low storage and transportation efficiency of the original silica fume, the silica fume can be slightly densified to a capacity of 250~350kg/m3. Slightly densified silica fume is suitable for mortar, grout and other applications.

     Silica fume slurry products are another technical way to solve the transportation and dispersion of silica fume. Silica fume is stirred with water to form a slurry of suspended particles with a solids content of 40 to 60%, which can be transported, conveyed and dosed like a liquid admixture, and it is easy to use, free of dust, and achieves the best dispersion effect. However, the production of stable suspended slurry has certain technical difficulties.