Effect of MgO on reduction swelling of Bayan Obo iron ore pellets
Due to the presence of more harmful elements such as K,Na and F,the Bayan Obo iron ore pellets show abnormal reduction swelling or even catastrophic swelling,which limits its application in pelletizing process.With the progress of beneficiation technology and the development of Bayan Obo west mine,the harmful elements such as K,Na and F are reduced year by year,which provides an opportunity for the realization of 100％Bayan Obo iron concentrate pellet production.In order to eliminate the influence of other components,pure chemical reagent MgO was selected as additive,and Bayan Obo iron ore was used as raw material to prepare Bayan Obo iron ore pellets by balling and roasting.The effects of MgO on the microstructure and properties of Bayan Obo iron ore pellets were studied by means of mineral phase microscope and SEM-EDS.With the increase of MgO content,the content of magnesium-bearing magnetite increases gradually,the content of hematite decreases,and the change of slag phase volume is not obvious.When the content of MgO increases,the porosity of Bayan Obo iron ore pellets increases,resulting in a downward trend in the compressive strength of pellets.When the mass percent of MgO increased from 1.5％to 4.5％,the compressive strength of the pellets decreased from 2 720.2 N to about 2 000.0 N.With the increase of MgO addition,the reduction swelling rate of Bayan Obo iron ore pellets showed a downward trend.When the MgO content increased from 1.5％to 4.5％,the reduction swelling rate of pellets decreased from more than 35.9％to 26.5％.Increasing the MgO content in Bayan Obo iron ore pellets can improve the reduction swell-ing performance of pellets.
MgOBayan Obo iron ore pelletsorganizationreduction swellingcompressive strength
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