The Long Term Stability of Virotec Reagents
The reagents used in Virotec technology have several remarkable characteristics that make them ideal for environmental remediation on land and in water. They have an excellent trace metal and metalloid binding capacity and, equally importantly, elements that are bound when the material is used to treat contaminated water or soil are held very tightly and only a small proportion can be released, even if the solid residue is leached at a pH of 2.88 (TCLP procedure). Furthermore, the longer the spent Virotec reagents are left to age after use, the more tightly the bound elements are held. As the residue ages some new metal-trapping capacity develops.
Virotec reagents are typically dry red solid powders that are a by product of bauxite refining and consist of a complex cocktail of minerals that include: abundant hematite, boehmite, gibbsite, sodalite, quartz and cancrinite, minor aragonite, brucite, calcite, diaspore, ferrihydrite, gypsum, hydrocalumite, hydrotalcite, p-aluminohydrocalcite, and portlandite, and a few low solubility trace minerals. Virotec reagents, unlike seawater-neutralised red muds, are manufactured products, where the manufacturing can be manipulated to alter the mineral composition based on the salts used to convert soluble alkalinity to insoluble forms. The exact composition and geochemical character of the Virotec reagents depends on operational conditions in the alumina refinery, the efficiency of Virotec’s Platform Technology Reagent their caustic recovery systems, the concentration and Ca:Mg ratio used for the alkalinity precipitation, and the type and quantity of additives used.