5. Marketing

Cement production absorbs 70% of vitrified slag production (corresponding to around 9% of French cement production), while most of the remainder is used in road construction, and is thus the source of large tonnages of slag gravel, up to 15 Mt/year. In all, more than 4 Mt/year of slag (vitrified and crystallized) are used for roads. Very large tonnages can also be used for civil engineering, but on an irregular basis (see [Doc. M 7 425] ).

As a co-product, slag is an inexpensive material, but bulky and heavy: transport costs therefore have a major impact on its marketability. In its crystallized form, it competes with local gravel, while in its vitrified form, it can be used at greater distances from its place of production, as its dosage in the slag gravel is lower: pre-grinding...