Material, and method of producing it, for immobilizing heavy metals later entrained therein

The field relates to structural material that immobilizes heavy metals impacting thereon, thus providing a safe environment for personnel in the area while preventing subsequent environmental degradation. More particularly, provided in one embodiment is a fiber reinforced foamed-concrete structure that includes constituents, including aluminum, that significantly reduce the mobility of heavy metals, including fine particles thereof, when the structure is subjected to various forms of erosion, including that from acidic aqueous solutions. Provided are structural material for bullet traps and the like, a method of producing it, and a structure comprising it. The material is suitable for entraining and immobilizing projectiles and fine particles in a sticky gel. It is prepared by mixing cement with a thickener to form a dry mixture. Water is mixed with a fine aggregate in a mixer. The dry mixture is combined with the aqueous mixture in the mixer to form a slurry. Calcium phosphate and an alumina compound are added, mixing each separately until homogeneous. The density of the mixture is measured and an aqueous foam is added to adjust the density to a pre-specified level. Fibers are mixed into the adjusted mixture to form a homogeneous slurry that may be poured into a mold or in place at a construction site. Upon curing, the material may be used as a structural component.