Technology Commercialization and Partnerships | BSA 99-09: Improved Ex-Situ Mercury Remediation

BSA 99-09: Improved Ex-Situ Mercury Remediation

BNL Reference Number: BSA 99-09

Patent Status: U.S. Patent Number 6,399,849 was issued on June 4, 2002

Summary

The present invention provides a process for the treatment of mercury containing waste in a single reaction vessel. The process is effective in treating various types of mercury contaminated waste; such as elemental mercury or mercury compounds, mercury contaminated bulk material, or mercury contaminated debris. The process is also effective for the treatment of mercury containing waste that also contains radionuclides, i.e. mixed wastes.

Description

This invention provides a process for the treatment of mercury containing waste, which includes a) stabilizing the waste with sulfur polymer cement under an inert atmosphere to form a resulting mixture and b) encapsulating the resulting mixture by heating the mixture to form a molten product and casting the molten product as a monolithic final waste form. The first step of the process (step (a)) is the stabilization of the mercury containing waste. This stabilization step includes combining mercury containing waste with sulfur polymer cement under an inert atmosphere to form a resulting mixture. Argon or nitrogen are preferred. The second step of the process (step (b)) is the encapsulation of the waste. In the encapsulation step, the resulting mixture of step (a) is heated to form a molten product, which is then cast as a monolithic final waste form. Additional sulfur polymer cement can be added in the encapsulation step if needed, and a stabilizing additive can be added in the process to improve the leaching properties of the waste form. The preferred weight ratio of SPC to mercury containing waste in step (a) is typically between about 0.2 to about 3.0, preferably about 1.0. The initial combining of mercury containing waste with the sulfur polymer cement can occur at a preferred temperature range of from about 20° C. to about 80° C. To facilitate the reaction, it is preferred that the sulfur polymer cement be reduced to a particle size of less than about 3000 microns, before being added as a reagent.

Benefits

This invention satisfies the standing need for a method of stabilizing and solidifying mercury containing waste so that it can be stored or disposed of without presenting a pollution problem.