title: Submerged-arc welding slags: characterization and leaching strategies for the removal of aluminum and titanium.
abstract: In the present study, submerged-arc welding slags were characterized by applying a variety of methods, including X-ray fluorescence, X-ray diffraction, particle size, Raman spectroscopy, and scanning electron microscope with energy dispersive X-ray analysis. The content of Al proved to be quite similar within neutral and acid slags (10-14%), while that of Ti proved to be much higher in acid slags (approximately 10%) than in neutral slags (<1%). The presence of spinel structures associated with Al species could also be identified in the analyzed samples. This characterization study was accompanied by leaching tests performed under changing operating conditions in an attempt to evaluate to what extent the Al and Ti bearing components could be removed from the slags. The leaching work involved three distinct strategies: (i) NaOH leaching followed by H(2)SO(4) leaching, (ii) acid leaching (HCl and H(2)SO(4)) using oxidizing/reducing agents, and (iii) slag calcination followed by H(2)SO(4) leaching. In the best result, 80% of Al was extracted in one single leaching stage after calcination of the acid slag with NaCl+C at 900 °C. By contrast, the removal of Ti proved to be unsatisfactory.
authors.affiliation: Departamento de Engenharia Metalúrgica e de Materiais, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, Campus Pampulha, 31270-901 Belo Horizonte, MG, Brazil.
authors.forename: Raquel
authors.initials: R
authors.lastname: Annoni
authors.forename: Poliana Santos
authors.initials: PS
authors.lastname: Souza
authors.forename: Martina
authors.initials: M
authors.lastname: Petrániková
authors.forename: Andrea
authors.initials: A
authors.lastname: Miskufova
authors.forename: Tomáš
authors.initials: T
authors.lastname: Havlík
authors.forename: Marcelo Borges
authors.initials: MB
authors.lastname: Mansur
mesh_terms: D000535:Aluminum / Q000737:chemistry*; D006851:Hydrochloric Acid / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D007220:Industrial Waste; D008855:Microscopy, Electron, Scanning; D059027:Recycling / Q000379:methods; D012965:Sodium Chloride / Q000737:chemistry; D012972:Sodium Hydroxide / Q000737:chemistry; D013059:Spectrum Analysis, Raman; D013464:Sulfuric Acids / Q000737:chemistry; D014025:Titanium / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D014896:Welding; D014961:X-Ray Diffraction
chemical_list: D007220:Industrial Waste; D013464:Sulfuric Acids; D014874:Water Pollutants, Chemical; D012965:Sodium Chloride; D012972:Sodium Hydroxide; D000535:Aluminum; D014025:Titanium; C033158:sulfuric acid; D006851:Hydrochloric Acid