| 摘要 |
A phosphate mineral based reactive barrier system. Phosphate minerals are known to be sinks for heavy metal contaminants. The reactive barrier prevents the release of contaminants from waste materials, sediments or dredged materials via reaction with the contaminants at the interface between the barrier and the waste material, sediments or dredged material. The barrier is comprised of a phosphate mineral material where the form of the phosphate mineral is variable but primarily insoluble. This barrier is placed below, around, and/or on top of the contaminated materials such that the contaminated materials are completely enveloped, capped, or contained by a grout curtain. The barrier can be in a (i) slurry form, (ii) blended matrix form with other inorganic agents, or (iii) composite form with a geotextile or geofabric. These methods of construction can be used singly or jointly. In some cases, pH control may be used to optimize the chemical reactions within the barrier system. The barrier mechanism relies on the phenomena of adsorption, surface precipitation and co-precipitation of metal phosphate surface precipitates to chemically retard diffusion from the waste material. Immobilization may also occur secondarily when a small percentage of the phosphate minerals partially dissolve and the phosphate precipitates with metals to form metal phosphate precipitates in the pore water system of the reactive barrier. The contaminated wastes, sediments or dredged materials may have been subjected to solidification or chemical stabilization or other forms of treatment prior to disposal. |
