1. a CTM – Centre Tecnològic , Av. Bases de Manresa 1, 08242 , Manresa , Spain Phone: Fax:
2. d Department of Mining Engineering and Natural Resources , Polytechnic University of Catalonia , Av Bases de Manresa 61, 08242 , Manresa , Spain
3. b ICREA, Polytechnic University of Catalonia , Av. Diagonal 647, 08028 , Barcelona , Spain
4. c Department of Chemical Engineering , Polytechnic University of Catalonia , Av. Diagonal 647, 08028 , Barcelona , Spain