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| Overview: |
A molten metal bath is at the core of the Catalytic Extraction Process (CEP), developed by Molten Metal Technology Inc., which converts hazardous wastes into products of commercial value. The liquid metal acts as a catalyst and solvent in the dissociation of waste feed and the synthesis of products. Molten metal causes complex compounds in the feed to be dissociated into their elements, which readily dissolve in the liquid metal solution. By adding select co-reactants and/or controlling operating conditions, the dissolved elemental intermediates can be reacted to form desired products of commercial value. Thermodynamics determine product synthesis, while solution equilibria determine partitioning between the metallic, ceramic, and gaseous product streams.
The gaseous product stream contains mostly synthesis gas, a mixture of carbon monoxide and hydrogen, which can be used as a feedstock by the chemical industry or as a low NOx fuel. Synthesis gas can also be separated to form pure hydrogen and carbon monoxide, both useful feedstocks for the chemical industry. The gaseous product stream can also contain commercially valuable acids such as hydrochloric acid. The ceramic product stream will contain alumina (Al2O3) and silica (SiO2) along with the oxide forms of other non-reducible metals. The ceramic material contains no detectable levels of organic compounds and passes the Toxic Characteristic Leaching Procedure (TCLP) extraction test for all metal constituents. The ceramic material can be processed into industrial abrasives, construction materials, or refractory base. By tapping the metal bath, reducible metals in the feed can be recovered as metal alloys and recycled. Volatile heavy metals in the feed, such as mercury, zinc, and lead, may evolve from the metal bath as vapors and can be recovered from the gas phase using a cold trap or high-efficiency filter. Feed conversion efficiency in the metal bath is driven by solvation effects with the carbon concentration being a key variable affecting feed conversion efficiency. The lower the carbon concentration relative to saturation, the more efficient feed conversion per unit time is achieved. Reducing the carbon concentration in the liquid metal at constant operating conditions can increase the destruction efficiency by several orders of magnitude. At high carbon concentrations, the addition of oxygen from the feed or as a co-reactant will convert the carbon into carbon monoxide which will be removed as a gaseous product. The CEP process has been designated by the U.S. Environmental Protection Agency (EPA) as Best Demonstrated Available Technology (BDAT) for all waste streams. In addition, the CEP process has received a determination as a recycling technology by the EPA, Texas, Massachusetts, Tennessee, and Ohio. The CEP process can also process low level radioactive wastes achieving an eight to 100 fold volume reduction. |
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| Compliance Benefit: | The use of molten metal processing of
hazardous waste can be used to meet land disposal limits under 40 CFR 268. Molten
metal processing may require an air permit under 40 CFR 70 and 71.
The compliance benefits listed here are only meant to be used as general guidelines and are not meant to be strictly interpreted. Actual compliance benefits will vary depending on the factors involved, e.g., the amount of workload involved. |
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| Materials Compatibility: | The molten metal process can handle a wide variety of organic, inorganic, and low level radioactive wastes. |
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| Safety and Health: | Proper design, operation, and maintenance of molten metal process system is required to ensure safe operation. All operators must be properly trained in the operation and maintenance of the system. Operators must also be trained in hazardous waste operations as required by Occupational Safety and Health Administration (OSHA) and EPA regulations.
Consult your local industrial health specialist, your local health and safety personnel, and the appropriate MSDS prior to implementing this technology. |
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| Benefits: |
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| Disadvantages: |
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| Economic Analysis: | The following cost elements for the recycling of hazardous wastes using the CEP is compared to incineration. Molten Metal Technology is interested in building regional processing centers, at their expense, at or near bases that can guarantee 5 to 10 years of wastes. They state that prices will be at or below Defense Reutilization and Marketing Service prices. Expected prices range from $0.38 to $5.37/lb depending on type of waste.
Assumptions:
Table 1. Annual Operating Cost Comparison for Molten Metal Process and Incineration
Economic Analysis Summary:
Click Here to view an Active Spreadsheet for this Economic Analysis and Enter Your Own Values. To return from the Active Spreadsheet, click the Back arrow on the Tool Bar. |
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| NSN/MSDS: | None identified.
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| Approving Authority: | Appropriate authority for making process changes should always be sought and obtained prior to procuring or implementing any of the technology identified herein.
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| Points of Contact: | For more information |
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| Vendors: |
This is not meant to be a complete list, as there may be other manufacturers of this type of equipment. Note: Molten Metal Technology may no longer be in operation. Molten Metal Technology, Inc. Technical Test Center 1000 Clearview Ct. Oak Ridge, TN 37830 Phone: (423) 220-5007 FAX: (423) 220-5047
Molten Metal Technology, Inc. |
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| Related Links: |
None. |
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| Sources: | Molten Metal Technology, Technical Attachments. Mr. Robert Sameski, M4 Environmental Management Inc., May 1996. Mr. Randy Davis, M4 Environmental Management Inc., May 1996. |