A process 1, characterized in that the iron oxides to be coated are γ Fe2 O3, {HEAD ~ Fe3 O4} or {TAIL ~ a bertholoid compound} having an FeO content of from 0 to 30% 
A process 1 , characterized in that the iron oxides to be coated are γ Fe2 O3 , { HEAD ~ Fe3 O4 } or { TAIL ~ a bertholoid compound } having an FeO content of from 0 to 30 %
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH