Catalyst On Coke Reactivity And Mechanism

The hot reactivity of coke, it can accurately reflect the ability of anti-dissolves in the blast furnace and the ability to undertake the load as the Skeleton of the stock column. Therefore improving coke quality, specially to improve it's thermal state performance which has already becomes a hot topic in the field of ironmaking. However, at present the research mainly focus on finding out the positive and negative catalytic material to the coke, which are relatively few to the catalyzed mechanism.In this experiment, we has compared several common materials to the coke which has positive and negative catalysis effect. As a basis on this, we choose each one positive catalysis and negative catalysis material to analyze its catalytic effect's mechanism.(1) Boric acid has the best negative catalytic effect on Coke, with the concentration increasing, it's negative catalytic effect increased. When the boric acid solution concentration of 3%, the reactivity of coke can reduce of 5.85%, and the immersion time of boric acid solution have no any impact on the catalytic effect.(2) The calcium oxide has the positive catalysis effect to coke, but it has different impact on the reactivity with it's different concentration. When the calcium oxide concentration is less than 1%, the reactivity has obvious change with the concentration, but when the calcium oxide concentration from 1%to 5%, the reactivity increases very much slightly, in 0.5%, and the immersion time have no any impact on the catalytic effect.(3) The reaction of coke with CO2 which not only includes the surface reaction, but also the internal reaction. In this paper, we according to different control steps to derive to the corresponding rate equation, Then bring the experimental data according to the thermal analysis into the equation, we can get under 1100℃, the controlling step of the reaction is internal proliferation. After according to the equation and the data, we can obtain the kinetic parameters of the process, namely the diffusion coefficient Dε=1.5×10-9m2/s.(4) Based on the reaction of C and CO2, we analyze the suppression Mechanism of the reaction. The boric acid contact with the carbon of the most edge's carbon net, the atom of the boric acid will first substitute for the carbon of the most edge's carbon net to prevent the reaction occur. Then replace the carbon of the inferior edge's carbon net, so as to improve the coke structure and enhance it's strength; at the same time, after the boric acid completely substitutes for the carbon of the edge's carbon net, because of boric acid have the strong negative electric, it can form negative ion on the surface of coke, which can prevent the formation of CO complexes and decrease the loss reaction of coke. Lead to the reactivity to drop unceasingly.(5) When add calcium oxide into, CaO combine with the activated atoms of the coke surface to generate two types of oxygen-containing intermediate product. Planar-type oxygen complexes Cf(Ca·O) and non-planar oxygen complexes C(Ca-O)Cf(Ca·O), the two kinds of complex compounds are easy to decompose, thus it has accelerated the response and play the role of positive catalysis.