Yes, it is quite common; this is a typical combination, particularly in dry extrusion granulation production lines. However, its prevalence depends on specific conditions, and it is not suitable for every scenario.

Fertilizer granules compaction machines—typically double roller press granulators—compress powdered raw materials into sheets or strips using high-pressure rollers, which are then crushed and screened to produce granules; the entire process requires neither added water nor drying. The double shaft paddle mixer is responsible for rapidly blending various raw materials and adjusting moisture content prior to extrusion.

There are three main reasons for this pairing. First, the double shaft paddle mixer offers high mixing efficiency; it can achieve uniform distribution of raw materials with significant density differences—such as urea, ammonium phosphate, and potash—in a short time, meeting the extruder’s requirements for feed consistency. Second, it allows for precise moisture adjustment during mixing, ensuring the material is in an optimal state before entering the extruder. Excessive moisture causes sticking to the rollers, while insufficient moisture leads to loose granules; the mixer’s forced convection facilitates rapid, uniform moisture penetration. Third, this combination is well-suited for small-to-medium-scale production involving multiple product varieties and lacking drying facilities, offering relatively low investment and energy consumption costs.

However, there are limitations to this setup. If the raw materials are highly sticky or have high fiber content, the double shaft paddle mixer may suffer from material wrapping or residue buildup; in such cases, other types of mixers, such as horizontal ribbon mixers, are more appropriate. Furthermore, for very large production capacities or products requiring extremely high granule sphericity, wet granulation methods—such as rotary drum or high-tower granulation—often offer greater advantages.

Overall, the combination of an extruder and a twin-shaft paddle mixer is a common and mature solution in the field of dry granulation, ideal for high-concentration formulations, small-batch multi-variety production, and simplified production line requirements.