Ciroval™ is a hydrometallurgical process designed for recycling, in an economical way, blast furnace sludge in the steel production route.

In a two-step process, Ciroval™ allows selective leaching of the zinc and lead contained in the blast furnace sludge and the recovery of the iron and carbon fraction.

Leaching under acidic and oxidative conditions at low temperature constitutes the first step of the process. A fine control of this leaching process enables a high recovery yield of the iron-carbon matrix, which can be recycled by being returned to the blast furnace route.

As a second step, this is followed by neutralisation during which a concentrated zinc-lead cake with limited iron content is produced. This generated by-product can be reused by the non-ferrous industry.

As each BF sludge material reacts differently, Paul Wurth is equipped with internal laboratory facilities and a movable pilot unit for on-site demonstration and trials.