Encontrados 8 documentos, a visualizar página 1 de 1
Valorização de lamas galvânicas por via hidrometalúrgica
Silva, João Eudes daTese de doutoramento em Engenharia Mecânica ; As empresas portuguesas do sector metalúrgico e metalomecânico abrangem uma vasta gama de actividades industriais e processos produtivos, sendo normalmente de pequena e média dimensão. Entre os processos, inclui-se o sub-sector dos tratamentos de superfície, que tem sido identificado como um daqueles com maior potencial de impacto em termos de poluição. Isto, devid...
Solvent extraction aplied to the recovery of heavy metals from galvanic sludges
Silva, João Eudes da; Paiva, A. P.; Soares, Delfim; Labrincha, J. A.; Castro, F.In this study, a hydrometallurgical treatment involving the solvent extraction and recovery of some heavy metals from a sulphuric acid leach solution of galvanic sludge, using di-(2-ethylhexyl)-phosphoric acid (D2EHPA) and bis-(2,4,4- trimethylpentyl)-phosphinic acid (Cyanex 272), both diluted in kerosene, has been investigated. The preliminary tests revealed the necessity to remove other metal species than zin...
Physical and chemical characterisation of metal finishing industrial wastes
Magalhães, Jorge M.; Silva, João Eudes da; Castro, F.; Labrincha, J. A.In EU countries approximately 150,000 ons/year of galvanic sludges are generated by 4000 industrial units from the orresponding wastewater treatment plants. These sludges are generally classified as hazardous (European Waste Catalogue as adopted in Council Decision 2000/532/CE and as amended by Decisions 2001/118/EC, 2001/119/EC and 2001/573/CE), basically due to the presence of heavy metals. This work attemp...
Leaching behaviour of a galvanic sludge in sulphuric acid and ammoniacal media
Silva, João Eudes da; Soares, Delfim; Paiva, A. P.; Labrincha, J. A.; Castro, F.Leaching studies of a sludge produced by the physico-chemical treatment of astewaters generated by a Ni/Cr plating plant were carried out in both sulphuric acid and ammoniacal media aiming to decide which of them would be the best treatment for this kind of waste material. The dissolution behaviour of some metals (Cu, Ni, Cr and Zn) was studied in order to assure the best metal recovery conditions in subsequent...
Effect of experimental variables on the inertization of galvanic sluges in clay...
Magalhães, Jorge M.; Silva, João Eudes da; Castro, F.; Labrincha, J. A.The incorporation of several industrial wastes in ceramic matrixes had been attempted as an effective low expense technique for the fixation of metallic species in usable products or simply to reduce the residue volume for further disposal. However, the dominant mechanism of the inertization process and the relevant influent parameters are still unknown, mostly due to the complexity of the systems. This work re...
Role of the mixing conditions and composition of galvanic sludges on the inerti...
Magalhães, Jorge M.; Silva, João Eudes da; Castro, F.; Labrincha, J. A.Hydroxide-metal sludges from electroplating industry are a potential source of environmental contamination due to their high content of heavy metals. The incorporation of these residues in a ceramic matrix can be a promising way to suppress the harmful effect of metals normally present in those sludges. This work reports the role of the mixing time between the waste and ceramic materials and of the calcination ...
Cations extraction of sandy-clay soils from cavado valley, portugal, using sodi...
Silva,João Eudes da; Castro,FernandoCases of contamination by metals in the water wells of the Cavado Valley in north-west Portugal can be attributed to the heavy leaching of clay soils due to an excess of nitrogen resulting from the intensive use of fertilisers in agricultural areas. This work focuses on the natural weathering characteristics of soils, particularly the clay material, through the study of samples collected near the River Cavado. ...
Cations extraction of sandy-clay soils from Cavado valley, Portugal, using sodi...
Silva, João Eudes da; Castro, F.Cases of contamination by metals in the water wells of the Cavado Valley in north-west Portugal can be attributed to the heavy leaching of clay soils due to an excess of nitrogen resulting from the intensive use of fertilisers in agricultural areas. This work focuses on the natural weathering characteristics of soils, particularly the clay material, through the study of samples collected near the River Cavado. ...
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