How it works and what it targets
One size or efficiency number cannot describe a powder process. Measurement basis, dispersion, sampling location, feed and operating conditions define its meaning. Technical data should state what is measured, how it is measured and which stream/system boundary it represents.
Reference process steps
- 1Define feed, products and sampling points.
- 2Align test methods, units and statistical bases.
- 3Compare results at equivalent product targets and energy boundaries.
Configuration and operating conditions
D10, D50 and D90
These are the sizes at which the cumulative distribution reaches 10%, 50% and 90% on the stated basis. Laser diffraction commonly reports a volume distribution; specify volume, number or mass basis and dispersion conditions. Equal D50 values do not imply equal coarse and fine tails.
Cut size and classification efficiency
Cut size characterizes how particles of a given size partition between coarse and fine streams. Classification-efficiency definitions vary; provide the calculation and feed/product masses. Neither is the same quantity as product D50.
Yield and recovery
Yield may mean the mass of the target size fraction relative to feed; recovery may refer to total powder or a target component. Define numerator, denominator and treatment of recycle and retained material.
Sphericity, circularity and aspect ratio
Sphericity describes similarity to a sphere in three dimensions and is not identical to two-dimensional image circularity. Aspect ratio can compare long/short axes or diameter/thickness for platelets. State imaging sampling and calculation methods.
Tap density and specific surface area
Tap density is powder mass per settled volume under a specified tapping procedure; specific surface area is surface area per unit mass. Size, shape, porosity and methods influence both. Neither alone establishes electrochemical or other functional performance.
Temperature, purity and specific energy
Low temperature needs a measurement point and run duration. Contamination control requires contact materials, analytes and detection limits. Specific energy uses acceptable product mass as its denominator and states inclusion of compression, steam, classification, collection and drying.
Information needed for selection
For selection and trials, provide full distributions, test methods, upper/lower product limits, functional targets and the energy-accounting boundary.
Discuss selection inputsTrial and acceptance considerations
Link each sample ID to its operating record and report. Interpret throughput, size and power for the same configuration and conditions rather than combining best values from different tables.