Reduction of Carbon-bearing Pellets of Oolitic Hematite in a Shaft Furnace

Abstract

AbstractWhen carbon-bearing pellets of oolitic hematite are treated in a shaft furnace, some problems are typically encountered: the metallization ratio of the metal pellets is low; the carbon-bearing pellets bond with each other at high temperatures; and the separation of phosphorus from iron is difficult. To solve these problems, experiments were conducted on oolitic hematite reduction in a resistance furnace and semi-industrial test shaft furnace. The results showed that the metallization rate reached 90% or greater under the conditions of a reduction temperature of 1150 °C, an atmosphere of simulated flue gas, and a reduction time between 1. 5 and 2. 0 h. The problem of high-temperature bonding among pellets can be solved by increasing the strength of the pellets, coating their surface with a surface transfer agent and maintaining an even temperature inside the shaft furnace. The basicity of the ore blend exerted no obvious effect on the magnetic concentrate and phosphorus content. The phosphorus content in the magnetic concentrate can be further reduced by improving the grinding capacity of the ball mills used in the experiments. On the basis of the experimental results related to oolitic hematite reduction with carbon-bearing pellets in a shaft furnace, the experimental requirements were satisfied with an average 88. 27% total Fe content and 0. 581% P content in the pellets.