Study On Pulverization And Vanadium Extraction Of Stone Coal Modified Converter Steel Slag

As steelmaking waste,steel slag has a huge output and contains many valuable elements.After treatment,it can be used in various industries with considerable economic value.However,its application is limited by its poor stability and grindability.It must be disposed before recycling.In this paper,the steel slag is modified to promote the precipitation of dicalcium silicate?C₂S?and to pulverize the comminuted steel slag by the principle of crystal transformation.Modifying the phosphorus and non-phosphorus steel slag by stone coal respectively,the influences of different basicity and the presence of element P on the phase change and self-pulverization of steel slag were studied The results show:C₂S is abundant in element P which inhibits its transformation.In order to make steel slag powdered,phosphorus must be removed;C₂S will precipitated first in a certain range of basicity,and C₂S decreases gradually when basicity is pretty high or lower than 2.0,and the efficiency of slag pulverization decrease.Because of the low content of element V and the high requirement of enrichment?basicity is lower than 1.6?,it is difficult to enrich and extract element V.At the same time,in order to study the influence of SiO₂ modification on the distribution of P element and the effect of slag pulverization,the experiment of carbothermal reduction and modification of SiO₂ under high temperature was carried out.It was found that element P only existed in C₂S and could be removed by reduction method and gasify it or transfer into iron phase and lower basicity at high temperature can help increase reduction rate of P;After reaction,C₂S is still solid which lower kinetics and lead to bad pulverization effect.To increase the reaction rate,the experiment of Si reaction under high temperature was carried out.It proved:kinetics of solid-liquid reaction is better than solid-solid reaction but still not good enough and reaction effect is not ideal;Low addition of Si elament will cause low reduction of P and high addition of Si will cause disapper of C₂S,the steel slag is difficult to be pulverized;The simultaneous use of a variety of components for modification can promote phosphorus removal and C₂S precipitation.Finally,to further improve the reaction conditions and study the effect of liquid-liquid reaction on rate of phosphorus removal and self-pulverization,The experiment of stone coal modification and reduction in melting slag under high temperature was carried out.The results showed:the absolutely reduction of P,Fe and V element could greatly increase the recovery rate of Fe,V and P element;When major P element is reduced,the pulverization rate of steel slag is high,slag and iron can be well separated.