As @aldux suggested, procedimentos would be a literal translation, which may work. However, I haven't been able to find "Procedimentos ..." as an actual title of conference proceedings.
Another related word is anais (which would be a literal translation of the English "annals"), which is used in the real world of conference proceedings, e.g. Anais do CNMAC, or Anais do IX Congresso Brasileiro de Atividade Física e Saúde. (For more examples, just Google.)
Another related word is acta, which strictly speaking is Latin, but apparently is used untranslated in Portuguese, too, e.g. Acta de Engenharia de Pesca.
I think anais is best if you're looking for a good equivalent of "proceedings" (in the sense of conference proceedings), but if you're just providing a straight translation (of an English journal name), maybe the literal procedimentos is better.