Zeolites are aluminosilicates that have a structure of uniformly shaped pores or channels, in which substances can be adsorbed. In the case of naturally occurring zeolites, this is usually water, which can be driven out of the pores by heating up the zeolite. The product can then be used as an extremely effective drying agent, e.g. for gases or organic solvents. Synthetic zeolites with defined pore sizes have been manufactured since around 1960. Since these can only adsorb molecules that are smaller than the pores, they are known as molecular sieves. The internal surface areas of these zeolites can exceed 1000 m²/g, offering many different potential applications, including as catalysts in the chemical industry.
For many applications, the zeolites – which come in powder form – are then still mixed with special additives and transformed into granulate form. Eirich mixers have proved themselves in many industries for mixing and granulating. Available in sizes from 1 l to 3000 l, these mixers only require a single moving mixing tool, which is known as the rotor. Depending on the task, the rotor can run at speeds up to more than 30 m/s. This makes it possible to generate high shear forces and distribute solids or liquids quickly. Varying the tools and speeds can have a considerable influence on the grain spectrum; granules with a d50 value ranging from < 100 µm to more than 5 mm are possible, depending on the material.
In the customer’s production, the two Eirich mixers in fully automatic operation replace six granulating drums, each of which had to be monitored and adjusted by workers. The short batch times and increased yield of good product proved to be advantageous, and significant energy savings were achieved overall. In addition to two mixers of type RV 16 (usable capacity of 900 l/1440 kg), Eirich also supplied the screw feeders, balances and control system. The new system is to be taken into operation in the spring of 2020. It will enable the manufacturer to supply customers with even better products.