scorify

To separate (an ore) into scoria and a precious metal.

To reduce to scoria, slag, or dross.

To reduce to scoria or slag; specifically, in assaying, to fuse so as to separate the gangue and earthy material, with borax, lead, soda, etc., thus leaving the gold and silver in a lead button; hence, to separate from, or by means of, a slag.

To reduce an ore to scoria.