Sulfur Concentrate Roasting Process Kinetics Of The Preparation Of Iron Ore Concentrate

In this paper, the kinetics and mechanism of the oxidation of pyrite was studied, and the optimum technical condition were determined by the experiment, which can slove the promble of rational using mine resource and provide a new way to utilization.The effect of heating rate was studied by thermal gravimetry/differrntial thermal ananlysis and a contracting core model was adopted in the oxidation processes of pyrite. The TG data were analyzed by means of the Coats-Resfen method and the Achar method on the conditions which obtained from the kinetic analysis. The results show that: high-, medium-grade ore in the first phase of oxidation process were accordance with the surface chemical reaction controlling step, and the second phase was fitted to the gas diffusion-controlled step in solid phase layer. Low-grade ore in the oxidation was controlled by the surface chemical reaction and the gas proliferation; coarse-grained level in medium-grade ore in the oxidation was controlled by the surface chemical reaction and gas diffusion reaction too, while the fine-grade minerals in the oxidation process is in line with gases in the solid-phase product layer of controlling step. The matching mineral of the high-grade ore in the oxidation was accordance with gases diffusion controlled step in the solid phase layer after matching with the compound additive TF, and the low-grade matching ore was controlled by two-step; the low-grade matching ore with the TF was controlled by the surface chemical reaction and diffusion reaction in the oxidation process.Using the kinetic analysis, the experiment condition of iron ore was gained in the baking pyrite. The results show that: in the temperature of 1073K and 4 hours' baking study, the qualified iron ore was available of TFe>65% and S>0.38%; and the low grade pyrite ore was not very good with TFe=52.62% and S=0.93% under 1223K and 8 hours' baking; The effect of particle size on the results of medium grade pyrite ore baking is less, the qualified iron ore of TFe>66% and S<0.25% was obtained under the temperature of 1073K and 3 hours' baking in the five particle size. In the same experiment condition, the qualified iron ore of TFe>65% and S<0.10% was available in the four matching mineral which was compounding with the TF; with the decreasing of the particle, the iron ore grade was also reducing while the matching mineral was baked in the 1073K and 3 hours, and the qualified iron ore was got of TFe>66% and S<0.5% excepting the matching ore of +0.15mm which was S>0.5%. The low grade pyrite ore with the addictive of TF was baked in the temperature of 1073K. and 8 hours, and the qualified iron ore was unavailable with TFe=60% and S=0.8%.