Recovery of silver residues from dental amalgam
J. appl. oral sci
; 18(2): 121-126, Mar.-Apr. 2010. ilus, tab
Article
de En
| LILACS
| ID: lil-550403
Bibliothèque responsable:
BR1.1
ABSTRACT
Dental amalgam residues are probably the most important chemical residues generated from clinical dental practice because of the presence of heavy metals among its constituents, mainly mercury and silver. OBJECTIVE:
The purpose of this study was to develop an alternative method for the recovery of silver residues from dental amalgam. MATERIAL ANDMETHODS:
The residue generated after vacuum distillation of dental amalgam for the separation of mercury was initially diluted with 32.5 percent HNO3, followed by precipitation with 20 percent NaCl. Sequentially, under constant heating and agitation with NaOH and sucrose, the sample was reduced to metallic silver. However, the processing time was too long, which turned this procedure not viable. In another sequence of experiments, the dilution was accomplished with concentrated HNO3 at 90ºC, followed by precipitation with 20 percent NaCl. After washing, the pellet was diluted with concentrated NH4OH, water and more NaCl in order to facilitate the reaction with the reducer.RESULTS:
Ascorbic acid was efficiently used as reducer, allowing a fast reduction, thus making the procedure viable.CONCLUSIONS:
The proposed methodology is of easy application and does not require sophisticated equipment or expensive reagents.Mots clés
Texte intégral:
1
Indice:
LILACS
Sujet Principal:
Argent
/
Déchets dentaires
/
Amalgame dentaire
/
Assainissement et restauration de l'environnement
langue:
En
Texte intégral:
J. appl. oral sci
Thème du journal:
ODONTOLOGIA
Année:
2010
Type:
Article
/
Project document