Waste and minerals; an overlooked connection

Mario Tribaudino (Department of Chemical, Life and Environmental Sciences, University of Parma)

The general perception of the "waste, waste disposal and waste recycling" problem does not involve the basic fact that for a great part they are made of solid crystalline material, with a counterpart in natural minerals. By this respect mineralogy, in its broad sense, provides a global perspective, from the composition of the earth crust to the processes of geochemical differentiation, mineral crystallization and growth, and, last but not least, mineral alteration. For instance, major challenges in waste disposal and recycling can be described as reactions between mineral, minerals and hydrosphere and minerals and biosphere. A successful recycling of secondary waste material will depend on solid state and melting reactions among the mineralogical constituents, and on their physical properties; leaching in disposal and recycling will be strongly affected by mineral alteration at some stage.  The literature in the waste management community is rather scarce, but the same conceptual and experimental methods which are used in academic investigation of rock weathering can be used in the applied studies to predict leaching behavior of wastes, and pollution of water sources by heavy elements.

Here we will discuss a few examples on minerals in waste and environmental media. More in detail we will show the differences and similarities in chemical, structural and mineralogical features between the mineral processes occurring in bottom and fly ashes from incinerator plants and in their natural counterparts, and how we can interpret them.