Process for removing cadmium from scrap metal
Abstract
A process is described for the recovery of a metal, in particular, cadmium contained in scrap, in a stable form. The process comprises the steps of mixing the cadmium-containing scrap with an ammonium carbonate solution, preferably at least a stoichiometric amount of ammonium carbonate, and/or free ammonia, and an oxidizing agent to form a first mixture so that the cadmium will react with the ammonium carbonate to form a water-soluble ammine complex; evaporating the first mixture so that ammine complex dissociates from the first mixture leaving carbonate ions to react with the cadmium and form a second mixture that includes cadmium carbonate; optionally adding water to the second mixture to form a third mixture; adjusting the pH of the third mixture to the acid range whereby the cadmium carbonate will dissolve; and adding at least a stoichiometric amount of sulfide, preferably in the form of hydrogen sulfide or an aqueous ammonium sulfide solution, to the third mixture to precipitate cadmium sulfide. This mixture of sulfide is then preferably digested by heating to facilitate precipitation of large particles of cadmium sulfide. The scrap may be divided by shredding or breaking up to expose additional surface area. Finally, the precipitated cadmium sulfidemore »
- Inventors:
- Issue Date:
- Research Org.:
- Savannah River Site (SRS), Aiken, SC (United States)
- OSTI Identifier:
- 35046
- Patent Number(s):
- 5405588
- Application Number:
- PAN: 8-276,721
- Assignee:
- Dept. of Energy, Washington, DC (United States)
- DOE Contract Number:
- AC09-89SR18035
- Resource Type:
- Patent
- Resource Relation:
- Other Information: PBD: 11 Apr 1995
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 05 NUCLEAR FUELS; CADMIUM; MATERIALS RECOVERY; RADIOACTIVE WASTE PROCESSING; SCRAP METALS; AMMONIUM CARBONATES; OXIDIZERS; AMMINES; CADMIUM CARBONATES; CADMIUM SULFIDES; PRECIPITATION; VITRIFICATION; WASTE FORMS
Citation Formats
Kronberg, J W. Process for removing cadmium from scrap metal. United States: N. p., 1995.
Web.
Kronberg, J W. Process for removing cadmium from scrap metal. United States.
Kronberg, J W. Tue .
"Process for removing cadmium from scrap metal". United States.
@article{osti_35046,
title = {Process for removing cadmium from scrap metal},
author = {Kronberg, J W},
abstractNote = {A process is described for the recovery of a metal, in particular, cadmium contained in scrap, in a stable form. The process comprises the steps of mixing the cadmium-containing scrap with an ammonium carbonate solution, preferably at least a stoichiometric amount of ammonium carbonate, and/or free ammonia, and an oxidizing agent to form a first mixture so that the cadmium will react with the ammonium carbonate to form a water-soluble ammine complex; evaporating the first mixture so that ammine complex dissociates from the first mixture leaving carbonate ions to react with the cadmium and form a second mixture that includes cadmium carbonate; optionally adding water to the second mixture to form a third mixture; adjusting the pH of the third mixture to the acid range whereby the cadmium carbonate will dissolve; and adding at least a stoichiometric amount of sulfide, preferably in the form of hydrogen sulfide or an aqueous ammonium sulfide solution, to the third mixture to precipitate cadmium sulfide. This mixture of sulfide is then preferably digested by heating to facilitate precipitation of large particles of cadmium sulfide. The scrap may be divided by shredding or breaking up to expose additional surface area. Finally, the precipitated cadmium sulfide can be mixed with glass formers and vitrified for permanent disposal. 2 figures.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Tue Apr 11 00:00:00 EDT 1995},
month = {Tue Apr 11 00:00:00 EDT 1995}
}