1. Federal University of Minas Gerais, Department of Chemical Engineering, Antônio Carlos Avenue 6627, 31270-901 Belo Horizonte, Minas Gerais, Brazil.
2. Centro de Desenvolvimento da Tecnologia Nuclear, CDTN, 31270-901 Belo Horizonte, Minas Gerais, Brazil.
3. Federal Universityof Rio Grande do Sul, Department of Metallurgy, Bento Gonçalves Av. 9500, 91501-970 Porto Alegre, Rio Grande do Sul, Brazil.