Steel product processing plant with scale separation and recovery system

A process for separating mixtures comprising water and scale deriving from a direct cooling and/or descaling of steel products comprising the following steps:

• (I) producing metal scale in an oxidation process of a steel product in continuous casting and/or rolling processes;
• (II) water jet descaling and/or direct cooling of the continuous casting and/or rolling product resulting in scale accumulation in the descaling and/or direct cooling water forming said mixtures comprising water and scale;
• (III) conveying the mixtures with large size scale, in at least a first pit (F1) with an overall depth of less than 10 m and preferably provided with a dredging device, such as a scraping conveyor, and removing the large size scale, in particular >500 μm, with said dredging device in a special container and diverting the clarified water, in particular by means of overflow elements present in said first pit (F1);
• (IV) conveying the mixtures with scale of fine particle size, in particular ≤500 μm, into at least a second pit with a depth less than 10 m;
• and preferably removing the mixtures with pumps, without separation of the scale from the water, from the second pit.

A steel product processing plant, comprising at least one rolling mill provided with a plurality of stands arranged in series and suitable to progressively reduce the thickness of the product to be rolled in the advancement direction, and optionally a descaling machine and a continuous casting line arranged upstream of said rolling mill and of said descaling machine, wherein said plant is further provided with:

• (a) at least one steel product direct cooling or cleaning system, or other system suitable to spray water on the product being processed;
• (b) at least one system for separating mixtures, in particular mixtures of a muddy nature, comprising water and scale, deriving from said at least one steel product direct cooling or cleaning system, or from said other system suitable to spray water on the product being processed comprising:
• (b-1) at least a first collection pit (F1) of the mixtures;
• (b-2) at least a second collection pit (F2) of the mixtures;
• wherein said pits (F1, F2) each have an overall depth <10 m, preferably <8 m, still more preferably <6.50 m;
• wherein said at least a first collection pit (F1) is fed with mixtures deriving from the casting or from said descaling machine and/or from one or more of the initial stands of the rolling mill and wherein said at least a second collection pit (F2) is fed by one or more groups formed by the remaining stands of the rolling mill;
• and wherein said first pit (F1) comprises inclined walls, in particular with an inclination between 45 and 75 degrees.