![]() ![]() Agglomerated materials are separated into uniform particles that are separated rapidly with sieving attachments. This high speed video clearly illustrates the dispersion of carbon black particles, their de-agglomeration, and progressive and comprehensive coating of the plastic pellets. Coating larger particles with smaller ones is a common processing application, and milling is often a part of the same process. Static and other physical forces combine to thoroughly coat particles, one material on another, layer upon layer. RAM can effectively mix both similar and dissimilar particle sizes and achieve a uniform final blend. RAM’s powder and solids mixing capabilities include: It causes them to divert their paths, collide and re-collide with other particles that are behaving in equally chaotic fashion to accomplish rapid and complete mixing. RAM’s unique sound-energy motion causes each powder particle to randomly collide with adjacent particles. In fact, RAM mixes solids 10+ times faster and more uniformly than traditional mixing methods. Powders of nearly any size, material characteristic, or morphology are rapidly and thoroughly mixed using RAM technology – including both free-flowing and cohesive powders. ResonantAcoustic® Mixing (RAM) is a game-changer for powder mixing. Thus, historically, a mixing technology has been selected based on the specific powder properties for a given mixture including flow characteristics and particle size. They are generally not capable of mixing both free-flowing and cohesive mixtures. RAM Powder Mixing Capabilitiesĭue to their mixing intensities and mechanisms, traditional mixing methods such as shear, diffusive, and convective are only effective at blending certain types of powder mixes. Additionally, larger powder particles may be dry-coated with a smaller particle to reduce interparticle forces and the tendency for aggregate formation. In many cases, cohesive powder mixtures require milling or sieving to break up the aggregates. In cohesive powders, the aggregates are clumps of the powder mixture that, if not dispersed properly, can lead to varied and uneven mixing in the vessel. To combat segregation, companies often minimize the time between the mixing step and the next step in the process, as well as implement special material handling processes.Īggregation is another issue, and often occurs with blending powders in cohesive mixtures. In many cases, larger particles segregate to the outside of the container while smaller particles remain closer to the center.Įach of these can occur anytime during the mixing step through transportation and storage of the material. Transportation occurs as the powder particles are jostled around during transport.Similar to percolation, vibration mostly occurs when powders being mixed include large and small particle sizes. Vibration occurs over time as smaller particles are vibrated and shift under larger particles.This form of segregation typically occurs when powder mixtures have a wider range of particle size. Percolation occurs when gravity pulls smaller particles into void spaces. ![]() Segregation typically occurs one of three ways: percolation, vibration, or transportation. Free-flowing powders are at a much higher risk of segregation compared to cohesive mixtures. Segregation, or demixing, is one of the biggest challenges in powder mixing. Additionally, the tendency of powders to be cohesive increases as particle size decreases in other words, smaller particles tend to be more cohesive while larger particles are more likely to be free-flowing. Several factors influence the formation of aggregates, such as moisture, electrostatic charges, and inter-particle forces. Free-flowing powders do not cling together, whereas cohesive powders stick to each other and form aggregates that do not disperse well during mixing. Powders can be grouped into two main categories based on flow properties: free-flowing and cohesive. Before diving deeper into the problems, it helps to have a basic understanding of powder flow characteristics. The main challenges with mixing powders are segregation and agglomeration, which are directly related to the flow characteristics and particle sizes of the powders in the mix. Powder mixing may seem simple, but is often complicated. The mixing step is crucial to many processes with the primary objective to achieve uniform distribution of all ingredients. Powder mixing is common in companies across many industries, including those in the pharmaceutical, advanced materials, and chemical sectors. ![]()
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