the.com/slag
the molten garbage of metal-making, useful enough that it paves your roads.
means The stony waste left over when metal is smelted out of ore — the scummy by-product skimmed off the melt, later crushed and reused in roads and concrete.
from From Middle Low German 'slagge,' meaning the dross or splinters thrown off when metal is struck or smelted — likely tied to the verb 'slagen,' to strike or beat (a cousin of English 'slay' and 'slaughter'). It entered English in the 1500s as a smelter's word for the glassy refuse of the furnace; only much later did 'slag' branch into mining slang and, in British usage, a coarse insult for a person.
- steel byproduct
- Floats atop molten metal, skimmed off as waste
- road builder
- Crushed slag forms asphalt and concrete aggregate
- British insult
- Doubles as slang for a promiscuous person
- volcanic cousin
- Spongy lava rock shares the name scoria
- glass cleaner
- Absorbs impurities, purifying the molten metal below
cornish tin mining waste — byproduct from centuries of tin extraction in cornwall, creating distinctive grey heaps across the landscape
blast furnace iron slag — molten waste from iron smelting at plants like those in pittsburgh and sheffield, cooled and reused in concrete
copper smelter slag — byproduct from porphyry copper mining, particularly abundant at bingham canyon mine in utah