Spray drying is a technique, which is used to produce spherical materials. It can be used as an intermediate process for drying and producing free-flowing powders, or as a real shaping technique producing attrition-resistant spherical particles with a diameter between 10 and 100 µm. These particles are used in fluidized beds. In a spray dryer, a hydrogel solution is sprayed through nozzles into a heated zone. Depending on the temperature, either drying or both drying and calcinations occur as the drops fall. There are also spray dryers with a nozzle blowing upwards, like a fountain. The type of liquid atomizer is very important for the maximum attainable particle size and the broadness of the particle size distribution.