Study On The Iron Sulfide Oxidation Process And Kinetics Under Low Temperatures

In this paper, the oxidized intermediates at solid phase and surface properties and the released law of gaseous products for equipment corrosion samples are studied. Combining with homogeneous precipitation sample, oxidation induction time and oxidation kinetics of sulfide iron is studied.The analysis of corrosion of equipment intermediate solid samples by using Raman spectroscopy and X-ray diffraction though low temperature pre-oxidation experiments showed that the former equipment corrosion sample is mainly in form of ferrous sulfide amorphous, the pre-oxidation sample presented to a multiphase system; its surface characteristics by BET method analysis concluded that with the extension of the pre-oxidation time, the product surface area decreases, the porosity decreases.Release of the formation mechanism and the use of various oxidation stage TG-FTIR analysis tools combined with research equipment corrosion samples. The study found: oxidized pyrolysis gaseous products including SO2, SO3 and a small amount of water, the amount of precipitation reaches its maximum when the temperature reached 715℃. Pyrolysis residual products indicate that S8 is not suitable for quantitative analysis of sulfur compounds in the oxidation of the iron index of product in the form of sulfur vapor.Study sample using equipment corrosion and oxidation induction experiments homogeneous precipitation sample thermal stability. Both samples in the 125~200 ℃ in active self-heating stage, poor thermal stability. Studies have shown that ultrafine particle size and sample the large particles are not conducive to the oxidation of iron sulfur compounds, oxidation induction time sample size range 44 ~ 74μm shortest higher propensity to spontaneous combustion; heating rate resulted in lower than the surface area of the sample at the same time enhance the desorption of the sample gas energy.The oxidation pyrolysis mechanism is analyzed by using TG-DSC sample heating rate of corrosion of the equipment. The results show that: the samples within 151.4~417 ℃ gradually phase transformation, starting pyrolytic oxidation Fe S2 within 450.5~533.5 ℃, within 668.8~840.7 ℃ sulfate(or sulphite) stepwise decomposition, pyrolysis weightlessness maximum value; weightlessness phase pyrolysis are SO2 precipitation, low temperature phase, SO2 mainly by phase oxidation of elemental sulfur precipitation generates your conversion, and high-temperature pyrolysis step segment generated SO2 sulfate is the main reason.