Thread Content
What? Vapor-phase silica can also be added to fertilizers! What on earth is this amazing product? Author/Source: Sinochem New Network; Date: 2021-08-19; Clicks: 18. The clumping problem in fertilizers usually occurs during their processing, storage, and transportation. It is primarily caused by the microscopic fertilizer crystals absorbing moisture, having their surfaces dissolve (deliquesce) and then recrystallize; during this process, crystal bridges form, causing small particles to combine into larger ones and resulting in clumping. Moreover, clumping in fertilizers reduces their fluidity, which hinders their processing and use. What? Vapor-phase silica can also be added to fertilizers! What on earth is this amazing product? The materials commonly used in the production of fertilizers, such as ammonium salts, phosphates, trace element salts, and potassium salts, mostly contain crystalline water, which makes them prone to absorbing moisture and forming clumps. For example, sulfuric acid tends to form clumps; phosphates and trace elements combine to form clumps that are less soluble in water. Urea, when in contact with trace element salts, releases water and forms clumps, as urea displaces the crystalline water from the trace element salts, resulting in a paste-like substance that then clumps together. The higher the air humidity, the more likely fertilizers are to absorb moisture and clump together; in dry weather or when the raw materials are dried, fertilizers are less prone to clumping. The higher the room temperature, the more favorable it is for dissolution; the raw material dissolves in its own crystal water, resulting in caking. At higher temperatures, water evaporates and it becomes less likely to clump together, but such temperatures are generally above 50°C. The greater the additional pressure from chemical fertilizers, the easier it is for crystals to come into contact with each other, leading to caking ； The lower the external pressure, the less likely it is to clump. Due to their ultra-fine particle size and large specific surface area, gas-phase silica particles, once dispersed in fertilizers, act as a \"film\" that encloses the larger fertilizer crystals, thereby separating them from one another. The small silica particles located between them function like the balls in bearings, allowing the fertilizer particles to flow freely while also providing physical separation between the particles and between the particles and moist air. Moreover, the well-developed pore structure of silica enables it to absorb water molecules from the surface of fertilizer crystals and from the air surrounding them, thereby reducing the moisture content in the environment in which the fertilizers are stored. This further prevents the fertilizers from becoming damp and clumping together during production, storage, and transportation. In summary, fumed silica can serve as an effective flow promoter and anti-caking agent in fertilizers, bringing great convenience to their processing, storage, transportation, and use.