Abstract: The carbonate bonded, press-moulded article is produced by press-moulding a particulate, carbonatable material that contains water and by carbonating the obtained compact with carbon dioxide gas. In order to be able to ensure an optimal compressive strength of the article two types of tests are provided. In the first type of test a sample of the particulate material is compressed with an increasing compaction pressure and when water starts to be expelled from the material as from a particular compaction pressure, the press-moulding step is performed with a compaction pressure which is at least 7 MPa smaller than this compaction pressure. In the second type of test different samples of the particulate material are press-moulded with different compaction pressures and, after having released the compaction pressure, the density of the compact is determined.

Abstract: The liquid steel slag (2) is poured in at least four successive layers (6-8), comprising a lowermost layer (6), an uppermost layer (7) and at least two intermediate layers (8), in a reservoir (3) and the layers of liquid steel slag are allowed to solidify. After having applied the uppermost layer (7), the solidified steel slag is cooled down more quickly by means of water. The average temperature of each of the intermediate layers (8) is kept at least until the start of the water cooling step, and this for at least one hour, above a minimum temperature which is equal to or higher than the temperature at which ?-dicalcium silicate is formed. In this way, more crystalline phases different from dicalcium silicates are formed so that the formation of fines by the transition of ? into ?-dicalcium silicates can be considerably reduced. A glassy material and/or a phosphorus containing compound is preferably added to the liquid slag to further reduce the formation of fines.

Abstract: The carbonate bonded, press-moulded article is produced by press-moulding a particulate, carbonatable material that contains water and by carbonating the obtained compact with carbon dioxide gas. In order to be able to ensure an optimal compressive strength of the article two types of tests are provided. In the first type of test a sample of the particulate material is compressed with an increasing compaction pressure and when water starts to be expelled from the material as from a particular compaction pressure, the press-moulding step is performed with a compaction pressure which is at least 7 MPa smaller than this compaction pressure. In the second type of test different samples of the particulate material are press-moulded with different compaction pressures and, after having released the compaction pressure, the density of the compact is determined.