Kinetics of Siderite Ore Roasting in the Shaft Furnace

Kinetics of the siderite ore roasting in the air, helium and hydrogen flows has been studied in a gasometrical unit with continuous mass variation logging. We have derived the expression for determination of an apparent degree of calcination and identified its dependence on the size of the prill, the heat treatment duration, and gas-phase composition. Using a generalized chemical kinetics equation, we have obtained a formula for calculation of the decomposition period for siderite ore samples. It has been found that calcination rate increases with the temperature rise, irrespective of the sample size and atmospheric composition. Calcination process has been studied at low temperatures. We have demonstrated that it is feasible to describe the process of siderite ore thermal dissociation by a first-order kinetics equation. We have obtained the expression to calculate the duration of this process depending on different parameters. Using a generalized chemical kinetics equation, we have obtained a formula for checking the expressions that describe the experimental data. We have studied kinetics of the reduction of roasted ore samples at various temperatures using different sizes of the samples. The obtained results have been applied for optimization of the design values and operating conditions of the siderite ore roasting in shaft furnaces. These will also be used for designing a shaft furnace consisting of a calcination zone, reduction zone (metallization zone) and metallized product cooling zone, which will increase iron content in the end-product to 65-70%.

Study of the process of siderite ore thermal treatment in a shaft furnace

Results of a study of kinetics of siderite ore roasting process in flows of air, helium and hydrogen presented. The study was carried out at mass measuring device with continuous registration of mass changing. An expression received for determining of apparent decarburization degree and its dependence determined on a piece dimension, thermal treatment duration and gas phase content. Using a generalized chemical kinetics equation, a formula received for determining of decomposition time of siderite ore specimens. Increase of decarburization pace at temperature rise determined for specimens of all dimensions independent on the atmosphere content and mechanism of decarburization process at low temperatures considered. A possibility shown to describe the process of thermal dissociation of siderite ore by a kinetic equation of first order and an expression obtained for determining of this process duration depending on different parameters. By application of generalized chemical kinetics equation a formula obtained, which was used to check the expression, describing the test data. Kinetic of roasted ore specimens reduction studied at different temperatures and specimens dimensions.The results obtained in this work were used for optimization of structural and mode parameters of siderite ore roasting process in shaft furnaces. They will be applicable at designing of a shaft furnace, comprising decarburization zone, reduction zone (metallization zone) and cooling zone of the metalized product, that will enable to increase the iron content in the final product till 65–70%.