Columbia Encyclopedia

Search results

500 results found

cyanamide process

(Encyclopedia)cyanamide process: see ammonia.

cyanide process

(Encyclopedia)cyanide process or cyanidation, method for extracting gold from its ore. The ore is first finely ground and may be concentrated by flotation; if it contains certain impurities, it may be roasted. It i...

contact process

(Encyclopedia)contact process: see sulfuric acid. ...

amalgamation process

(Encyclopedia)amalgamation process əmălˌgəmāˈshən [key], in particular, a method to extract gold and silver from ores. The ore is crushed and treated with mercury, in which the metal dissolves. The amalgam i...

Frasch process

(Encyclopedia)Frasch process fräsh [key] [for Herman Frasch, the German-American chemist who devised it], process for the extraction of sulfur from subsurface deposits. Three pipes, one inside another, are sunk to...

Haber process

(Encyclopedia)Haber process häˈbər [key], commercial process for the synthesis of ammonia, NH3. Pure hydrogen and nitrogen gases are mixed in the appropriate proportion, heated to between 450℃ and 600℃, comp...

flotation process

(Encyclopedia)flotation process, in mineral treatment and mining, process for concentrating the metal-bearing mineral in an ore. Crude ore is ground to a fine powder and mixed with water, frothing reagents, and col...

Mond process

(Encyclopedia)Mond process: see under Mond, Ludwig. ...

Parkes process

(Encyclopedia)Parkes process: see silver.

Wacker process

(Encyclopedia)Wacker process, an industrial process for the manufacture of ethanol by oxidizing ethene. For example, bubbling ethylene and oxygen when treated by an acidified water solution of palladium and cupric ...