a sustained phenomenon or one marked by gradual changes through a series of states

an industrial process for making graphite by heating a mixture of coke and clay

an industrial process for making steel using a Bessemer converter to blast air through molten iron and thus burning the excess carbon and impurities; the first successful method of making steel in quantity at low cost

an industrial process for extracting gold and silver by treating ore with a sodium cyanide solution

a process that removes suspended dust particles from a gas by applying a high voltage electrostatic charge to the particles and collecting them on charged plates

a process that uses heat to separate a substance into its components