Method for inhibiting malignant reduction swelling of iron pellets

Abstract

The invention discloses a method for inhibiting malignant reduction swelling of iron pellets. The method comprises the following steps of, (1), determining proper preheating and roasting temperatures through a pellet test, and carrying out fine tuning optimization by controlling the preheating temperature to be 800-850 DEG C and the roasting temperature to be 1200-1220 DEG C; (2) finely grinding iron ore concentrate until the particle size of -500 meshes accounts for more than 70%; (3) adding minerals of which the main component is silicon dioxide or the iron ore concentrate of which a small amount of gangue component is mainly silicon dioxide into pelletizing raw materials as a promoting agent to promote the diffusion of volatile components generated during preheating roasting, so as to effectively inhibit the reduction swelling of the pellets; and (4) taking at least one of the steps (1), (2) and (3) to control the reduction swelling rate of the pellets within 20%. According to the method, the reduction swelling rate of the pellets subjected to malignant reduction swelling can be reduced to be within the normal reduction swelling range.

Description

technical field [0001] The invention relates to the field of pellets for smelting raw materials and ore pretreatment in the metallurgical industry, in particular to a method for inhibiting the malignant reduction and expansion of iron pellets. Background technique [0002] Pellets are one of the main raw materials for blast furnace ironmaking, and the reduction expansion rate of pellets is one of the main indicators to measure its quality. If the reduction expansion of the pellets exceeds the normal expansion range, it will lead to the increase of furnace dust in the blast furnace, the poor air permeability of the furnace charge, and cause hazards such as hanging material collapse and furnace wall nodulation, which will seriously affect the normal production of the blast furnace. , The problem of malignant reduction and expansion of pellets is a problem that must be solved in pellet production. [0003] The reduction expansion rate of ordinary iron ore pellets is generally ...

AI Technical Summary

Problems solved by technology

Although the reduction expansion rate of malignantly expanded pellets can be controlled within the normal expansion range by increasing the proportion of bentonite and other additives, the proportion often needs to be more than 5% to 6%, which is uneconomical and not suitable for popularization and application.

[0005] In short, the commonly used measures to suppress the reduction and expansion of pellets have great limitations. When 100% of the easily expandable polymetallic iron ore is used, the reduction expansion rate cannot be controlled within the normal expansion range.