F A Ortega Riejos
University of Seville, Spain

M Lega
Parthenope University of Naples, Italy

H Itoh
Raremetal Recovery Institute, Japan

C Ferreira
CERNAS, Polytechnic of Coimbra, Portugal

E Garrido Vazquez
Federal University of Rio de Janeiro, Brazil

B Krumay
Vienna University of Economics and Business, Austria

J Lu
UiT The Arctic University of Norway, Norway

M Marafi
Kuwait Institute for Scientific Research, Kuwait

J C Mora Barrantes
National University of Costa Rica, Costa Rica

F Ntuli
University of Johannesburg, South Africa

J B Park
Seoul National University, South Korea

G Passerini
Marche Polytechnic University, Italy

N Quaranta
National Technological University, Argentina

E C Rada
Insubria University, Italy

A Sgobbo
University of Naples Federico II, Italy

R Sjoblom
Lulea University of Technology, Sweden

R Teta
University of Naples Federico II, Italy

Y O Yusuf
Ahmadu Bello University, Nigeria