| Grant number: | 06/03164-0 |
| Support Opportunities: | Scholarships in Brazil - Scientific Initiation |
| Start date: | August 01, 2006 |
| End date: | July 31, 2007 |
| Field of knowledge: | Health Sciences - Dentistry - Dental Materials |
| Principal Investigator: | Marília Afonso Rabelo Buzalaf |
| Grantee: | Heloisa Aparecida Barbosa da Silva Pereira |
| Host Institution: | Faculdade de Odontologia de Bauru (FOB). Universidade de São Paulo (USP). Bauru , SP, Brazil |
Abstract The Laboratory of Chemical Residues of Bauru, located in the Department of Biological Sciences/Biochemistry of Bauru Dental School/USP, has been developing a program of recovery of chemical residues generated in the clinics and laboratories of research of the campus and the Hospital of Cranio Facial Abnormalities (HRAC). The residues of xylenes, acetone, alcohol and amalgam receive the due treatment and come back toward the productive chain. However, in the residues of the amalgam after distillation for withdrawal of mercury, other metals still remain. Among these is the silver, with 32.5 - 37%. Due to this, a methodology for its recovery is being searched. Knowing that the process of casting for this residue could not be used, due to the existence of mercury traces, we opted to a methodology where another resource was used. From the methodologies of Pécora et al. (1998), Alekseevskii; Goldberg (1931) and Bendassolli, et al. (2003) some adaptations for the reduction of the metallic silver have been made. In a pilot study, 25 g of residue after removal of mercury were used, from which 9 g of metallic silver were obtained. The treatment consisted in the dissolution of this residue with the use of 32.5%HNO3, followed by precipitation with 20%NaCl. In the sequence, under constant heating and agitation with 10% NaOH and 2.5% Sucrose, the sample was reduced to metallic silver. With this, it was possible to minimize the environment contamination, besides returning the silver to the productive chain, reducing financial wastefulness. Thus, the objective of this study will be to implant in a higher scale the methodology developed through this study pilot, searching solutions to optimize the recovery of the silver from processed amalgam residues, after mercury removal. In addition, the efficiency of the recovery process will also be evaluated by the method of Volhard (Gaubeur et al., 2004). | |
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