| 摘要 |
1333544 Urea; melamine STAMIOARBON NV 9 Feb 1972 [13 Feb 1971] 6155/72 Heading C2C In the synthesis of urea or melamine, the processing of the intermediate ammonium carbamate solution at elevated temperature is conducted in plant wherein at least the surfaces thereof which are in contact with the solution are made of a nickel-free ferritic steel consisting essentially of at least 25% by weight of chromium, from 0 to 3% by weight of molybdenum, and having a combined content of carbon plus nitrogen of not more than 0À035% by weight and the balance of iron. |
