Experimental Study On Recovering Iron And Dephosphorization From Converter Steelmaking Slag In Microwave Processing

The converter steel slag is a kind of important secondary resource, which is rich in CaO, Fe, Mn.Part of slag is usually recycled in the iron and steel plant. In this process, the key is to solve theproblem of phosphorus enrichment. Removing the phosphorus away from the converter steel slag andrecycling Fe, Mn and other metal elements not only make full use of resources, but also protect theenvironment and make a efficient comprehensive utilization of converter steel slag. Microwaveheating relies on the material’s dielectric loss to generate thermal effects, which stands out for itstimeliness, selectivity, uniformity while comparing with the traditional heating modes. Microwaveheating has a broad application prospect in the field of metallurgy.The experiment was taken in an industrial microwave oven under the protection nitrogen. Mainlystudies on the influences of different process parameters such as reduction temperature, carbonequivalent, reducing agent, particle size, holding time on the iron yield and dephosphorization, thedistribution of phosphorus in slag, iron and gas.On the study of the iron yield, the results show that when the reduction temperature is1400℃,the carbon equivalent is in the double amount, granularity is0.15mm, holding time is45min withanthracite as reducing agent, the highest iron yield is93.6%. When using the anthracite as reducingagent, the higher temperature, the more carbon equivalent and the longer holding time then the higheriron yield is. Besides within a certain scope of the particle size, the iron yield is increase, with theincrease of particle size.On the study of the dephosphorization effect of steel slag in the microwave, the results show thatthe highest dephosphorization rate is93.8%when the reduction temperature is1400℃, the carbonequivalent is in the double amount, the granularity is0.15mm and the holding time is45min by usingthe anthracite as reducing agent. With the increase of temperature, carbon equivalent and holding time,the total rate of dephosphorization and gasification rate of dephosphorization also increases. The typeof the reducer conducts an impressive influence on the total rate of dephosphorization while has aunconspicuous influence on the gasification rate of dephosphorization, With the decrease of theparticle size, the total dephosphorization rate increases, while the gasification rate ofdephosphorization declines.Different steel slags contain different iron yield and dephosphorization rate, the iron yield and thedephosphorization rate can be improved by adding SiO2.The reaction product of XRD, SEM/EDS analysis results show that the main elements in the slagare Ca, Mg, Si and O elements, the phase composition is Ca3Mg(SiO4)2, C2S, C3S, Ca2Al2SiO7, theiron bead is mainly composed by Fe as well as Mn, P, C elements.