Research On Change Of Slag Composition And Phase In ESR

The slag composition in electroslag metallurgy process was in a continuouschange,as a result, slag properties will be changed, the product quality, relavanttechnical and economic index in electroslag remelting process（ESR）can be affected incorrespondance up to now, the machnism and the influence of this change to theremelting process is not systematically studied. The relavant research will be oftheoretical and practical significance. Segregationcrystallization of slag skell which mayinfluence on the change of slag composition was researched in this paper.Based on the theoretical discussion and research of domestic and foreign relevantreferences,several representative slag system from the binary to three-element andquaternionic slag system was studied. The difference of chemical composition and themechanism of formation of slag crust produced in different periods of smelting process,and the change of composition and crystallization conditions of clinker which wasformed of solidification slag pool in the end of smelting was analysised by phaseobservation, X-ray diffraction analysis and SEM analysis.The research of clinker phase indicated that there was a greater difference ofcomposition.Between the began smelting slag and the end of smelting slag, the oxygencontent is increased obviously in the final slag.It have a tendency of CaF2contentdecrease from top to bottom side in smelted slag of binary and ternary slag series, and inredical direction, the CaF2content is increased and then go down from outside to inside.The distribution of Al2O3is negative correlation with CaF2.In the smelted slag withquaternionicsystem, the distribution of MgO Al2O3is increased from top to bottom, anddecreased first and then down again from outside to inside.Research on the slag skin showed that, There was a delaminating phenonmenon in ESR, and its composition and thickness changed a lot which was all decided to by thetemperature of slag pool and the―micro-circular slag pool‖.The segregation(选分)crystallization in slag skell is high aluminum compounds and MgO Al2O3.The contentof segregation crystallizationrising is gradually increased from outside to inside intwo-layer slag skell, and is increased first and then decreased in three-layer slag skell.From bottom up, content of segregation crystallization, i.e, Al2O3and MgO Al2O3isreduced gradually. the The segregation crystallinity can directly lead to continuouschanges in the slag pool ingredient.