Basic slag

1.

A by-product from the manufacture of steel by the basic process, used as a fertilizer. It is rich in lime and contains 14 to 20 per cent of phosphoric acid. Called also Thomas slag, phosphatic slag, and odorless phosphate.

Noun

1.

basic slag - slag produced in making steel; low in silica but having large amounts of calcium phosphate; useful as fertilizer

dross, scoria, slag