The differences of reduction behaviors between iron ore lump and pellets were studied by conducting low temperature reduction degradation,static load reduction and droplet tests.These tests simulated the conditions of reduction temperature and hydrogen-containing gas in COREX.Due to its dense structure and low porosity compared with pellets,lump ore possesses poor reduction degradation index (RDI) and slower reduction rate in early and medium reaction stages,showing signs of lower strength,lower softening and melting temperatures,as well as a wider melting zone and higher △P.That provides some basis to explain the phenomena of differential pressure rise,metallization decline and more sticking after the usage of lump ore in COREX plant.