The colorimetric determination of aluminum by means of Friochromo Cyanine R after the separation of interfering ions with Zerolito FF (chloride form) is further examined.Procedures for the determination of aluminum in alloy steels,copper-aluminum alloys and iron ore are devised.The analyses may be accomplishe 1 in a short time; for aluminum in alloy steels or in copper-aluminum alloys,it takes half an hour,and for aluminum in iron ore,an hour.