Improvement of strength of carbon-bearing pellets containing magnesium oxide

摘要

Carbon bearing pellet is widely known to have very good performance such as low fuel rate and excellent metallurgical properties in the blast furnace style iron making process compared to the traditional method. However, carbon bearing pellet is difficult to produce by the disc pelletizer method because of the lower compressive strength. Furthermore, the bonding problem at high firing temperature makes it difficult to develop by the common method. In this study, an experimental investigation on carbon bearing pellet with magnesium oxide (MgO) was performed to improve the compressive strength of the pellet. Under the condition of 6% coal and 1.5% bentonite and the firing temperature in the range 1200-1300 degrees C, the compressive strength of the carbon bearing pellet increased with increasing firing temperature; however, the compressive strength decreased later with the continuous increase in temperature according to the experiment. The optimized temperature for the maximum compressive strength of pellet was in the range 1250-1300 degrees C. If the firing temperature was out of the optimized range, the high compressive strength of the pellet was lost.