Waelz slag used in commercial ceramic bricks

Researchers from the University of Cantabria (Santander, Spain; www.unican.es) have developed a process for incorporating Waelz slag into ceramic clay construction bricks, offering an alternative for disposal of the industrial byproduct. The engineers replaced between 20 and 30% of clay with slag, and found that the inclusion at that level did not have any significant detrimental effect on the physical, mechanical or chemical properties of the ceramic bricks. Incorporation of slag at levels higher than 30% begins to result in more significant effects on the brick properties. The Waelz process is a commercial technology used to recover volatile metals from electric-arc-furnace (EAF) dust. It generates a product mixture of ZnO and PbO, as well as slag, the nonvolatile component of the dust, consisting mostly of iron oxide. Landfilling the slag can represent an environmental burden and can mean disposal costs in some areas. In addition to providing a way to manage waste material, the partial substitution of the clay with waste slag “also contributes to reducing the depletion of natural resources, minimizing production costs and providing a way to manage waste material,” the research team says. The real push for incorporating…