in ironmaking, the parts of the iron ore that are not pure iron
Undesirable chemical elements or minerals.
Any substance dissolved or suspended in water which alters chemical and/or physical properties of the pure substance.
foreign matter. Bits that shouldn't be there - ever had a fly in your drink
Mixed with other substances and lower in quality.
the quality or state of being unclean.
Any substance that contaminates another.
Undesirable foreign material(s) in a pure substance or mixture.
Undesirable elements or compounds in a material.
Elements or compounds whose presence in a material is undesired.