Binders: How they work and how to select one
Binders are required in some types of bulk solids agglomeration to produce strong final agglomerates. By permanently bonding particles, a binder allows the agglomerates to withstand the rigors of storage, handling, packaging, and shipping. This article first discusses binder types and their applications, then explains how to select a binder for your process. A related sidebar discusses lubricants, another common agglomeration additive.
The term agglomeration commonly describes all size enlargement methods that gather fine, intermediate, and even coarse particles into larger masses. In agglomeration, binding forces must act between individual particles. Several binding mechanisms exist: solid bridges, liquid bridges [interfacial forces and capillary pressure at freely movable surfaces], viscous bonding [adhesion and cohesion forces in binders that aren't freely movable], attraction forces between solid particles, and interlocking particles [form-closed bonds].