Can one mixer handle both dry materials and pastes?

09-08-2013

Q: Most of the processes in my specialty chemical company are batch and handle only dry materials. However, some materials go through a paste phase. Can one mixer handle both dry materials and pastes?

A: Yes, but your company will have to invest more capital in the more sophisticated mixer required, when for most of your processing a less sophisticated mixer (for instance, a tumble blender also called double cone mixer, which handles only dry solids and is simply constructed and thus less expensive) is all you need. If you need to handle both dry and paste phases, you can select a ribbon mixer(vertical ribbon mixer or horizontal ribbon mixer), which can handle dry materials and, usually, pastes; however, this impeller-driven ribbon mixer is more expensive than a tumble blender(double cone mixer). If your paste is very difficult to handle, you can select a multiple-motion mixer (paddle blender or plow mixer) with impellers that rotate with planetary motion or intermeshing sigma blades, but this is even more expensive.
To determine which mixer is suited to handling your paste without being overly sophisticated or expensive, have the paste tested. Paste – a material partway between a dry material and a liquid – can mean different things to different people and can’t be as easily characterized as a dry material. To double check that the equipment will work with your dry material as well as your paste, especially if you select a multiple-motion mixer(double shaft paddle blender or plow mixer), have a small sample of the dry material tested. This will determine, for instance, whether the multiple-motion mixer’s higher shear rate will degrade the dry material during your simpler mixing processes. Vortex Mixing Technology Co., Limited can test a small sample of your material in various mixers with different impeller arrangements, depending on your material‘s characteristics. Vortex Mixing Technology Co., Limited performs such tests at no charge.