Wooden model of a cyanide plant. A cyanide plant was used for dissolving gold from finely divided ores by means of dilute solutions of sodium or potassium cyanides. The model has five metal bins, there is some rust on the bins and scorch mark on the wooden base.mining, equipment, cyanide plant, gold cyanidation (also known as the cyanide process or the macarthur-forrest process) is a hydrometallurgical technique for extracting gold from low-grade ore by converting the gold to a water-soluble coordination complex. it is the most commonly used leaching process for gold extraction. the ore is comminuted using grinding machinery. depending on the ore, it is sometimes further concentrated by froth flotation or by centrifugal (gravity) concentration. water is added to produce a slurry or pulp. the basic ore slurry can be combined with a solution of sodium cyanide or potassium cyanide, however many operations utilize calcium cyanide, which is more cost effective. to prevent the creation of toxic hydrogen cyanide during processing, slaked lime (calcium hydroxide) or soda (sodium hydroxide) is added to the extracting solution to ensure that the acidity during cyanidation is maintained over ph 10.5 - strongly basic. lead nitrate can improve gold leaching speed and quantity recovered, particularly in processing partially oxidized ores.