This glossary defines the terms that appear on technical data sheets, certificates of analysis and purchase specifications for industrial minerals and polymers. Each definition is written to be quoted on its own.
Particle size and physical properties
| Term | Definition |
|---|---|
| D50 | Median particle size: 50% of particles by volume are smaller than this value. |
| D97 / D98 | The size below which 97% (or 98%) of particles fall; describes the coarse end of the distribution. |
| Top cut | The largest particle size in a powder, often reported as D97, D98 or D100. |
| Particle-size distribution (PSD) | The full spread of particle sizes in a powder, usually measured by laser diffraction. |
| Laser diffraction | A particle-size method that measures how particles scatter a laser beam. |
| Sieve residue | The percentage of material retained on a sieve of a given opening, e.g. 45 µm. |
| Mesh | The number of sieve openings per linear inch; higher mesh means finer sieve. |
| Bulk density | Mass of loose powder per unit volume, in g/cm³; affects bag size and container loading. |
| Specific surface area (BET) | Total particle surface per gram, in m²/g; finer powders have more surface. |
| Oil absorption | Grams of oil needed to wet 100 g of powder; indicates binder or resin demand. |
| Mohs hardness | A 1–10 scratch-hardness scale; talc is 1, calcite 3, quartz 7. |
| Moisture | Free water in a powder, measured as weight loss at 105 °C. |
Optical properties
| Term | Definition |
|---|---|
| Brightness R(Y) | Reflectance under a Y (green) filter as a percentage of a white standard. |
| ISO brightness R457 | Reflectance of blue light at 457 nm; common in paper. |
| Whiteness | A combined measure of how close a colour is to ideal white. |
| CIE L*a*b* | Colour coordinates: L* lightness, a* red–green, b* yellow–blue. |
| Yellowness index | A number expressing how yellow a material appears. |
Chemistry and minerals
| Term | Definition |
|---|---|
| GCC | Ground calcium carbonate: natural limestone, marble or chalk ground to powder. |
| PCC | Precipitated calcium carbonate: chemically produced CaCO₃ with controlled particle shape. |
| Calcite | The most common crystal form of calcium carbonate. |
| Coated / surface-treated | A mineral whose surface has been modified, usually with stearic acid, to make it hydrophobic. |
| Hydrophobic / hydrophilic | Water-repelling / water-attracting. |
| Activation degree | Percentage of a coated powder that floats on water; indicates coating completeness. |
| LOI (loss on ignition) | Weight lost on heating to high temperature; shows carbonates, bound water or organics. |
| HCl-insolubles | Material that does not dissolve in hydrochloric acid; mainly silica and silicates in CaCO₃. |
| Talc | Hydrated magnesium silicate with a platy structure. |
| Lamellarity | How flat and wide talc plates are relative to their thickness. |
| Gypsum | Calcium sulphate dihydrate, CaSO₄·2H₂O. |
| Plaster of Paris (POP) | Calcium sulphate hemihydrate, CaSO₄·½H₂O, made by heating gypsum. |
| Anhydrite | Calcium sulphate without water, CaSO₄; forms when gypsum is over-calcined. |
| Quicklime | Calcium oxide, CaO, made by calcining limestone. |
| Hydrated lime | Calcium hydroxide, Ca(OH)₂, made by adding water to quicklime. |
| Available lime | The fraction of lime free to react; the key commercial value of lime. |
| Reactivity (lime) | How fast quicklime reacts with water, measured by temperature rise. |
| Silica sand | Quartz sand of controlled purity and grain size, mainly SiO₂. |
| AFS grain fineness number | A foundry measure of average sand grain size; higher means finer. |
| Respirable crystalline silica | Fine silica dust small enough to reach the deep lungs. |
Polymers and processing
| Term | Definition |
|---|---|
| PP | Polypropylene: stiff, light polymer used in woven bags, fibres and moulded parts. |
| HDPE | High-density polyethylene: tough, rigid PE used in pipes, containers and crates. |
| LDPE | Low-density polyethylene: flexible PE used in film and coatings. |
| LLDPE | Linear low-density polyethylene: tougher, more puncture-resistant film PE. |
| Homopolymer / copolymer | A polymer made from one monomer / from two or more monomers. |
| MFI / MFR | Melt flow index or rate: grams of polymer flowing through a die in 10 minutes under set conditions. |
| Density (polymer) | Mass per volume in g/cm³; separates HDPE, LDPE and LLDPE. |
| Masterbatch | A concentrated pellet of additive, pigment or filler in a carrier resin. |
| Filler masterbatch | Masterbatch with a high mineral content, commonly 70–80% calcium carbonate. |
| Carrier resin | The polymer that holds the filler or pigment in a masterbatch. |
| phr | Parts per hundred resin; ingredient weight relative to 100 parts polymer. |
| Dispersion | How evenly a filler or pigment is distributed in a polymer. |
| Raffia | Stretched PP tape used to weave sacks and fabrics. |
| Tenacity | Tape or fibre strength relative to its weight, in g/denier or cN/tex. |
| Denier | The weight in grams of 9,000 m of tape or fibre. |
| Plate-out | Deposits that build up on dies, rolls or moulds during processing. |
| Heat deflection temperature (HDT) | The temperature at which a plastic bends under a set load. |
| Nucleating agent | An additive that speeds up crystallisation of a polymer. |
Trade and documents
| Term | Definition |
|---|---|
| TDS | Technical data sheet: typical properties and specification limits of a grade. |
| SDS | Safety data sheet: hazards, handling, storage and transport information. |
| COA | Certificate of analysis: test results for a specific batch. |
| Batch / lot number | The code linking a product to its production run and COA. |
| FIBC | Flexible intermediate bulk container, or jumbo bag, typically 500–2,000 kg. |
| Valve bag | A block-bottom bag filled through a valve; stacks neatly and loads efficiently. |
| Incoterms | International trade terms (e.g. FOB, CFR, CIF) defining costs and risks between seller and buyer. |
| FOB | Free on Board: seller delivers goods loaded on the vessel at the port of shipment. |
| CIF | Cost, Insurance and Freight: seller pays freight and insurance to the destination port. |
| HS code | Harmonised System code used to classify goods for customs. |
| Certificate of origin | A document confirming the country where goods were produced. |