Optimization of experimental conditions on preparation of oxidized pellets with New Zealand sea sand ore

Abstract

In the iron and steel industry, improving the usage amount of New Zealand sea sand ore as a raw material for ironmaking can reduce the production costs of iron and steel enterprises to a certain extent. In this paper, the New Zealand sea sand ore without any grinding pretreatment was used as raw material, oxidized pellets were prepared by using a disc pelletizer, and the experimental conditions for preparing oxidized pellets were investigated and optimized. The effects of binder dosages, roasting temperature and roasting time on the properties of pellets were mainly investigated, and the effects of roasting temperature and roasting time on the microstructure of oxidized pellets was discussed by researching XRD patterns and SEM-EDS. With the increase of binder dosages, the drop strength of green pellets and the compressive strength of oxidized pellets were gradually increased. With the increase of roasting temperature and roasting time, the compressive strength of oxidized pellets increased gradually. When the amount of New Zealand sea sand ore was increased to 40–50%, the optimal process conditions for the preparation of oxidized pellets were as follows: the dosage of binder was 1.5%, the roasting temperature was 1200 °C, and the roasting time was 20 min.