| A large amount of steel slag and will be produced in steelmaking process,in order to increase the recycling amount of steel slag in iron and steel enterprises,it is necessary to remove the phosphorus and sulfur elements in steel slag to avoid its enrichment in steelmaking process and harm quality of steel products.Based on the review of various treatment methods and recycling technologies of steel slag at home and abroad,according to the characteristics of molten steel slag and the electrochemistry theory of molten slag,this paper proposes to use electric field to treat molten steel slag and study the directional migration of phosphorus in slag,three kinds of electrode pairs,including Fe-Fe pair,Fe-C pair and C-C pair,are used to study the effects of voltage respectively,external electric field(EEF)direction and electric field type(frequency of pulsed electric field)on the removal of P2O5from Ca O-Si O2-Al2O3system slag.The Fe-C electrode pair takes the molten metal under the slag as one electrode and the graphite rod as the other electrode.During the cooling process,the electric field is applied until the slag solidifies.The results show that the content of P2O5in slag decreases with the increase of voltage under two electric fields:graphite rod as cathode and liquid steel as anode(reverse EEF)and graphite rod as anode and liquid steel as cathode(positive EEF).The decrease of P2O5content in the sample with reverse EEF is more obvious.At 6V,the P2O5content in the sample slag is reduced to 15%of the blank sample.In order to verify how the P2O5in the sample slag is separated from the slag,the electric field is applied during the heat preservation process,and the metal samples and slag samples are taken to analyze the composition.The results show that the phosphorus in the slag is mainly separated from the slag in the form of entering into the molten steel after the electric field is applied.In order to verify how the P2O5in the sample slag is separated from the slag,the electric field is applied during the heat preservation process,and the metal samples and slag samples are taken to analyze the composition.The results show that the phosphorus in the slag is mainly separated from the slag in the form of entering into the molten steel after the electric field is applied.In addition to changing the thermodynamic conditions of the reaction between the slag and the electrode,the applied electric field can also improve the kinetic conditions of the reaction due to the gas produced by the anodic reaction.Combined with the test results,it is speculated that the reaction between slag and metal in the test are not balanced,the stirring effect of anode gas in the sample with reverse EEF is stronger than that with positive EEF,so the effect of reverse EEF is more obvious.At the same time,the experimental results also show that the dynamics occupies the main position in the thermodynamic and dynamic changes caused by the EEF.The results show that the content of P2O5in the slag treated by the pulsed electric field is also significantly reduced,which is equivalent to that of the reverse EEF,but has nothing to do with the frequency of the pulsed electric field.The C-C electrode pair takes graphite rod and graphite crucible as the electrode,and only slag is contained in the crucible.The P2O5content in the sample with graphite crucible as cathode and graphite rod as anode(sample with reverse EEF)decreases with the increase of voltage.The P2O5content in the slag decreases to 58%of the blank sample at 6V.However,for the sample with graphite crucible as anode and graphite rod as cathode(sample with positive EEF),the content of P2O5first increases and then decreases slowly.When the voltage is 3V,the content of P2O5in the slag reaches the highest value,which is 118%of the blank sample.The effect of EEF on P2O5content in slag is not found in Fe-Fe electrode pair experiment. |
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