ZEOLITE-BASED BINDER FOR SOLIDIFICATION/STABILIZATION OF INDUSTRIAL HAZARDOUS WASTE
A zeolite-based binding material for solidification/stabilization of industrial hazardous waste has been developed. This binding material will quickly solidify the hazardous waste, physically and chemically absorb the hazardous ions, and stabilize them by substitution in hydration products.
A zeolite-based binding material has the following desirable characteristics:
- Stabilizing heavy metal ions, e.g. cadmium, zinc, mercury, etc., and radioactive ions, e.g. strontium, cesium, etc. in hazardous waste;
- Quick setting solidification (setting time in the range of 10-30 minutes);
- Sufficient strength for solidified forms (compressive strength in the range of 7-15 Mpa);
- Cost Effective
The zeolite-based binding material can be manufactured with commercially available raw materials, existing cement mixing equipment and low energy cost processes.
The use of zeolite as a binding material in the formulation of hazardous waste encapsulating concrete capitalizes on the unique properties of high porosity, surface area, and exchange capacity as well as its pozzolanic activity. Zeolites are alumino-silicate minerals with a three dimensional porous molecular framework. The excess net negative charge imbalance gives them a high cation exchange capacity. The regular void spaces in the lattice allow molecular sieving and capturing based on size and charge. The porosity creates a large effective surface area for adsorption. The combined large surface area and charge character import pozzolanic activity to the mineral grains by improving hydraulic cementing properties while increasing buffering capability and corrosion resistance to resulting concrete.