Proper Bulk Cargo Shipping Name of the cargo in the IMSBC Code is " Iron Oxide, Spent or Iron Sponge, Spent UN 1376 obtained from coal gas purification ". Is a porous form of iron made from reducing (removing oxygen from) an iron oxide at such low temperatures that no melting occurs and this is usually done from the purification process of coal gas. Material is powdery and is either black, brown, red or yellow in colour. Strong odour may taint other cargoes. Used as a polishing agent for glass, precious metals, diamonds, in magnets etc. Bulk density: 2,222 kg/m3.