Jet Mill Versus Planetary Mill – Comparison of Properties of Milled ZnFe2O4 Pigment

Abstract

In this study the powders of zinc ferrite obtained by milling in a planetary mill and a jetmill were compared. The spinel ZnFe2O4 was prepared by calcination of initial mixture of ZnO and Fe2O3 in stoichiometric ratio at 1100°C/4h. The pressures from 4 to 10 bars were used for dry milling in the jet mill Labomill (FPS, S.r.l., Italy). The next samples were prepared with using the planetary mill Pulverisette 5 (Fritsch, Germany), i.e. by wet milling in ethanol for the grinding time from 10 to 40 min. The agate balls and the zircon beads were used. Our attention was focused on determining of the fundamental pigmentary properties, which could be affected by grinding. The particle size distribution was measured by Mastersizer 2000/MU (Malvern Instr., BG). The surface area was obtained with using NOVA 1200e (Quantachrome Instruments, USA). The colour properties were studied with help of ColourQuest XE (HunterLab, USA).