Potassium and chlorine distributions in high temperature halloysite formed deposits Piotr Plaza, Jorg Maier, Izabella Maj, Waldemar Gądek and Sylwester Kalisz E3S Web Conf., 82 (2019) 01011 Published online: 01 February 2019 DOI: 10.1051/e3sconf/20198201011