pig iron vs basic iron

pig iron and basic iron both are nouns.

Word	Noun	Adjective	Verb	Adverb
pig iron	Yes	No	No	No
basic iron	Yes	No	No	No

As nouns, basic iron is a hyponym of pig iron; that is, basic iron is a word with a more specific, narrower meaning than pig iron:

pig iron: crude iron tapped from a blast furnace
basic iron: pig iron containing a high percentage of phosphorus; used in making steel by a process that removes the phosphorus

Other hyponyms of pig iron include cinder pig, mine pig, spiegel, spiegel iron, spiegeleisen.

pig iron (noun)	basic iron (noun)
crude iron tapped from a blast furnace	pig iron containing a high percentage of phosphorus; used in making steel by a process that removes the phosphorus