Caking Tests

Caking can mean different things in the context of powder and  material handling. It can mean a powder forms a completely solid mass after it has been exposed to pressure or has been stored for a long time. It can mean that it looks "clumpy" to a user. It can mean the powder has formed loose or strong agglomerates that affect its performance. For this reason, there are many ways to define and test caking. Mercury Scientific offers two basic types of caking tests that can be modified to match application requirements.

 

Unconfined Yield Strength and Time Unconfined Yield Strength with EVOLUTION Powder Tester

The unconfined yield strength measures the strength of the bonds between particles in a powder or granular material after the powder has been exposed to pressure or storage conditions. The pressure is applied for a short time to produce instantaneous results and then for longer periods to measure the effect of storage conditions over time.

 

CAKING Test with REVOLUTION Powder Analyzer

Cohesive particles in a powder can form larger agglomerated particles and clumps with material handling. This process can be intentional as in a granulation process or can be unintentional as in caking during storage. Either way a powder's quality is affected by the formation of these agglomerates and clumps. The REVOLUTION Caking Test can be used to study powders that exhibit particle size change during mixing, blending, transportation, production processing and/or storage. 

The caking process is studied by comparing a powder's flow properties in a rotating drum before and after exposure to pressure or storage.  If a sample is affected by the pressure or storage, then the powder flow properties change. Once your powder has caked, the REVOLUTION Caking Test can also test the strength of the caked particles by increasing the drum rotation speed to force high velocity collisions between the powder particles.  These collisions could cause the caked particles to break up. The caking software compares the results of the powder's properties after storage and after the increase in velocity to see if the powder remained in a caked state.  

 

Link to instrument-specific test pages: