We worked with one customer processing silicates that had used rotary airlocks for a long time to do this. They were changing out airlocks/components every couple of months due to blade and housing wear, even with wear resistant components. We displaced the rotary airlock with a double flap-gate with wear resistant components. This lasted about twice as long, but still meant unwanted downtime. A third solution was then tried: a solids screw pump. Although more expensive than the other two technologies, the customer was able to get over one year between replacement part /maintenance intervals. The technology choice is based mainly on the abrasiveness of the materials being processed, the process condition, and the cost of downtime. We have other customers in similar applications where rotary airlocks and double flapgates last a long time on relatively abrasive materials.