Study On The High-temperature Reduction Reaction Characteristics Of Iron Concentrate Particles Based On Microtitration

In this paper,a micro titration method of ferric chloride decomposition potassium dichromate for the determination of total iron content in iron concentrate was established.The concentration,dosage and dissolving stirring time of ferric chloride suitable for the micro titration method were confirmed.Based on the established micro titration method and high temperature hot stage microscope in situ technology,the effects of gas flow rate,particle size and reduction temperature on the high temperature reduction reaction of iron concentrate powder were studied,and the high temperature reduction kinetics characteristics of iron concentrate powder were obtained.The main contents include:(1)An iron trichloride decomposition-potassium dichromate microtitration method was established to determine the total iron content in iron fine powders(<100?g).The ammonium ferrous sulfate calibration experiment is used to determine the decomposition of ferric chloride-potassium dichromate can be used for the titration of trace iron elements,the experimental error is 0.40%;The titration of the total iron content in the iron powder is used to determine the concentration,dosage,decomposition and stirring time of ferric chloride suitable for the microtitration process,and the experimental error is 0.31%;The titration experiment of fine iron powder is used to verify that the microtitration method can be used to determine the total iron content in the fine iron powder.The experimental error is 0.51%.(2)The effects of gas flow rate and particle size on the high temperature reduction reaction of iron concentrate are studied by high temperature hot stage microscope.The study found that when the reducing gas flow rate is above 200 mL/min,the reduction degree does not change with the increase of the gas flow rate,and the external diffusion is eliminated..Taking the smallest particle size as the standard,the reaction time is 25 s,the reduction degree of the iron fine powder with a particle size of 100 ?m is 0.95,Compared with iron fine powder with a particle size of 150 ?m and 180 ?m,and the reduction degree decreases by 2.20%and 8.18%,respectively.The fine iron powder with a particle size of 100 ?m is selected to eliminate the influence of internal diffusion.(3)The kinetics of high temperature reduction of iron concentrate in CO atmosphere was studied by means of high temperature microscope.The study found that the surface of the sample after reduction at 1000? and 1100? showed a loose and porous structure,and the surface of the sample after reduction at 1200?to 1400? showed a "nodular" raised structure(elemental iron),accompanied by melting.Compared with the reduction rate at 1000? the increase in the initial reaction rate from 1100? to 1400? is 6.26%-56.25%.The unreacted nucleus model was used to determine the kinetic parameters of the reduction reaction of iron fine powder from 1000? to 1300?.The control step of small particle size is interfacial chemical reaction,and the activation energy is 147.0 kJ/mol.