The Mineralogy, Corrosion Resistance and Properties of Six Commercial Rebonded Fused Grain Magnesite-Chrome Bricks

摘要

In 1991/1992, INCO undertook a successfulR&D program aimed at extending the lining lives of thetop blown rotary converters (TBRCs) at its Copper CliffNickel Refinery (CCNR) and the electric furnace atINMETCO. At the laboratory scale, this effort wasdivided into three phases. In the first part,mineralogical work was performed on six refractoriesthat were either currently being used to line thesevessels or were considered suitable alternatives. Inthe second art, this mineralogical knowledge was usedto help determine the compositions of slags that wouldnot corrode these bricks at the operating temperature(~1600 deg C) of the above furnaces. Finally, severalimportant properties of the six refractories weremeasured to complete their evaluation as candidatalinings. This paper reports the results of all threephases of the laboratory scale R&D work.The mineralogical work showed that rebonded fused grainmagnesite-chrome (RFG-MC) bricks consist principallyof periclase with minor amounts of free chromite andtrace quantities of the silicates monticellite andsometimes olivine. The bricks are principally heldtogether by periclase-periclase direct bonding. Ofnote, the bulk of the chromite exists as exsolvedprecipitated blebs within the periclase grains. Theselikely re-dissolve at high temperature.Slage on the periclase liquidus coexist stably withthese refractories. Examples are presented usingCaO-MgO-Al_2O_3-SiO_2 slags at ~1600 deg C.Finally, the two refractories manufactured using closeto 100% fused grain material generally outperformed theothers in terms of physical properties and certainlywere superior in their resistance to slag penetration damage.