CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY

**Definition:** This place covers:

Granulation processes or devices, e.g. by dividing liquid material into drops in drums or in fluidised beds or by expressing the material through sieves, making particulate materials hydrophobic.

Chemical or physical processes or apparatus therefor concerning:

Chemical processes involving a gas, e.g. gas passing through fixed beds or fluidised beds, reacting liquid with gaseous media other than in the presence of solid particles, reacting gaseous media with gaseous media or reacting gaseous media with non-particulate solids.

Chemical processes involving a liquid, e.g. liquids passing through fixed beds or fluidised beds, reacting liquid with gaseous media, reacting liquid with liquids or reacting liquids with non-particulate solids.

Production of colloidal materials or their solutions, e.g. making microcapsules by physical drying, spraying, coacervation or polymerisation.

Sorbent or filter aid compositions comprising inorganic or organic material, sorbents specially adapted for chromatography and processes for preparing or regenerating thereof.

Catalysts:

Ion exchange processes, e.g. cation, anion or amphoteric ion-exchange; regeneration of ion-exchangers and apparatus therefor.

**Glossary:** - catalyst: any substance that increases the rate of a reaction without itself being consumed. Catalysts are commonly used in their pure form or in combination with suitable carriers. It covers also a carrier forming part of the catalyst. - chromatography: a process in which a fluid is caused to flow along a linear path comprising a sorbent, with which the fluid competes in affinity for a constituent of the fluid. The constituent is sorbed from the moving fluid by the relatively immobile sorbent and re-dissolved by a later passing portion of the fluid until an equilibrium of the sorbing-dissolving step is set up causing the constituent to concentrate in a specific volume of the sorbent and to move along the path of the fluid at a rate slower than such fluid. - fluidised particle: finely divided solid particle lifted and agitated by a stream of fluid - fluidised-bed: fluidised-solid contacting technique in which finely divided particles are lifted and agitated by a rising stream of fluid - molecular sieve: material (e.g. zeolitic, mesoporous) having cavities and channels which by their size allow some molecules to pass through, but prevent others - solid particle: particle whether catalysts, reactant or inert in solid, semi-solid or pasty state - sorbent: a material which separates a constituent from a fluid mixture containing such constituent by sorption. The action in most instances is that of selective retention (i.e. the sorbent removes only the part of the fluid mixture for which it has the greatest affinity). - zeolites: crystalline aluminosilicates with base-exchange and molecular sieve properties, having three-dimensional, microporous lattice framework structure of tetrahedral oxide units; compounds isomorphous to those of the former category, wherein the aluminium or silicon atoms in the framework are partly or wholly replaced by atoms of other elements, e.g. by gallium, germanium, phosphorus or boron