Transportation and storage of silicon powder

Silica particles are extremely fine, compared with other powder materials, its specific surface area is up to 20000-280000cm2/g, about 50 times greater than the fly ash, about 50 to 100 times greater than concrete. The production and applications of ultra-fine particles are the high-tech in eighties. At present, there are already have Al2O3, zirconium oxide and other magnetic ultrafine particles, silicon carbide, silicon oxide and other metal powder and alloys ultrafine, can be used for precision ceramics, high-performance powder metallurgy, conductive materials, magnetic sensors, transducer and other new materials. Therefore, the ultrafine characteristic of silicon powder has a very important role on improving and enhancing the properties of the material.

Condensed silicon powder in the gas, liquid, back to the process of the phase change by the surface tension, form of different sizes round pellets, and the surface is more smooth, some of them may be two or more spherical granules stick coagulation in together. Doped silica material, this tiny spherical body can play a smooth lubrication role, reduce the friction between the particles, thereby improving the workability of the material, water can be reduced, improve the material properties.

Due to the small proportion of silica fume heap, big natural inclination, fluffy, easy to fly, shipping and unloading by the container is not easy, and the packaging and transportation costs are expensive. Currently, the form of countries on silica processing, storage and transportation is various, generally packaging with the form of raw powder, lumpy, beads in bulk, bags and others, silicon powder can also be made into the mud or mud paste with the right amount of water supply to the users.

Bulk loading is generally transporting with a covered or enclosed dump truck cement tanker. Bags loading are usually heavy 25kg, big bags loading can up to 300-500kg. Pocket generally use paper or plastic. At present, Tangshan, Shanghai, Taiyuan and other places in China, silicon powder are mostly with double plastic bag, net weight 10-15kg.

In order to improve the transport efficiency of silicon powder, some manufacturers taken densification measures. Such as some factories in Canada, Sweden, the United States add water to silicon powder slurry tank (water and silica fume are 50%). The mud made by Norway was containing 35% silicon powder, and directly delivered to the concrete plant. In this way, the transport costs are lower, not dust while handling, good working environment; easy pumping, high degree of mechanization.

The method of silicon powder into a ball often used the traditional ball machine, Norway, Soviet Union, Japan and other countries have been reported. Use paper waste, silicon sodium, NaCl, alkali or alkaline earth metal hydroxide and other solution or water as a binder, the diameter of the made pellets is 5-25mm, are generally as silicon powder iron raw material returned to the furnace. Pellet’s own strength some rely on the adhesion of adhesive, some need to calcination.

In the late seventies, a number of suppliers used efficient alkaline agents combined with silicon powder beads to produce concrete admixtures. After 1982, beaded admixture has new development, Norway used different alkaline agents, efficient alkaline agent and silicon powder bonded into different performance beads admixtures for cement, concrete and other mineral ingredients large (including low cement castable, etc.). This additive is extremely easy to use, can be dissolved in water after decomposition. At present, some countries have also developed this technology. Beaded silicon powder’s diameter is 0.5mm, its bulk density from the original bulk silicon powder 0.2t/m3 increased to 0.6t/m3. It can make the packing and shipping charges decreased by approximately 60%. Handling efficiency increased, storage space and area reduced, also improve the working conditions and environment.

Source:http://www.mhcmp.com