Extraction of mercury and mercury compounds from contaminated material and solutions

• US 5,226,545 A
• Filed: 10/19/1992
• Issued: 07/13/1993
• Est. Priority Date: 10/19/1992
• Status: Expired due to Fees

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Foust, Donald F.
• Primary Examiner(s): DAYOAN, DARRELL G
• Application Number:
  US07/963,225
• Time in Patent Office: 267 Days
• Field of Search: 209/3, 209/12, 209/15, 209/16
• US Class Current: 588/303
• CPC Class Codes: A62D 2101/24 containing heavy metals
• CPC Class Codes: A62D 2101/43 containing heavy metals, in the bonded or free state
• CPC Class Codes: A62D 2203/04 Combined processes involving two or more non-distinct steps covered by groups A62D3/10 - A62D3/40
• CPC Class Codes: A62D 3/33 by chemical fixing the harmful substance, e.g. by chelation or complexation
• CPC Class Codes: A62D 3/38 by oxidation; by combustion
• CPC Class Codes: B03B 1/00 Conditioning for facilitating separation by altering physical properties of the matter to be treated
• CPC Class Codes: B03B 9/062 the refuse being glass
• CPC Class Codes: B09C 1/02 Extraction using liquids, e.g. washing, leaching , flotation
• CPC Class Codes: C21C 2005/4666 for charging with organic contaminated scrap
• CPC Class Codes: C21C 2005/5282 with organic contaminated scrap
• CPC Class Codes: C22B 43/00 Obtaining mercury
• CPC Class Codes: Y02P 10/134 by avoiding CO2, e.g. using hydrogen
• CPC Class Codes: Y02P 10/20 Recycling
• CPC Class Codes: Y02W 30/60 Glass recycling

Abstract

Mercury and mercury-containing compounds can be removed from soil, sand, and similar materials by a remediation method in which the contaminated material is treated with an aqueous composition comprising an oxidant, such as iodine, and a complexing or solubilizing agent, such as potassium iodide, the liquid and solid phases are separated, and further processed as needed.

Claims

1. A process for removing mercury from mercury contaminated solid materials which comprises treating the contaminated materials with an aqueous extractant-composition comprising an oxidizing agent in an amount sufficient to oxidize elemental mercury to the mercuric oxidation state and a complexing agent in an amount sufficient to form a water-soluble complex with mercuric compounds and separating the aqueous extractant composition from the solid materials.

2. The process of claim 1 in which the oxidizing agent is iodine and the complexing agent is a water soluble halide having the formula RX or RX₂ wherein R is selected from the group consisting of potassium, lithium, sodium, calcium, and ammonium and X is iodide or chloride.

3. The process according to claim 1 in which the extractant composition contains from about 0.005 to about 1 mole per liter of potassium iodide and from about 0.0001 to about 0.5 moles of iodine per liter.

4. The process of claim 1 in which the extractant composition contains about 1 mole of potassium iodide and about one-half mole of iodine per liter.

5. A process according to claim 1 for removing elemental mercury and chemically combined mercury from mercury-contaminated solid material which comprises contacting the mercury-containing solid material with an aqueous extractant composition containing from about 0.1 to about 1 mole of potassium iodide and from about 0.0001 to about 0.5 mole of iodine per liter for a period of time sufficient to solubilize substantially all of the mercury contaminant, separating the solid material from the mercury-containing extractant, and electrochemically removing the mercury from the aqueous extractant to regenerate a mercury-free aqueous extractant composition.