Controllable atmosphere rotary hearth furnace process for producing direct reduction iron

Abstract

The invention relates to a controllable atmosphere rotary hearth furnace process for producing direct reduction iron, comprising the steps of: pressing iron ore concentrate powder into pellets with the diameter of 30-40mm or directly using lump ores with the granularity of 5-25mm; preheating to 700-1000 DEGC at first; then mixing with a reducing agent; adding the mixture into a controllable atmosphere rotary hearth furnace; laying materials with the thickness of 30-70mm, wherein during laying materials, if the common iron ore powder pellets are used 5-10mm of reducing agent is paved at the bottom of the furnace in advance, and 5-10mm of reducing agent is scattered to the mixture at last, and the step of scattering the reducing agent is not needed if internally arranged carbon pellets are used; enabling all materials to operate in the controllable atmosphere rotary hearth furnace for 3-8h at 1200-1400 DEG C; discharging the materials out of the furnace by a water-cooled spiral discharging machine introduced with protective gas; and carrying out magnetic separation on the discharged materials to obtain sponge iron pellets. The materials are preheated at first and then reduced by the controllable atmosphere rotary hearth furnace, and the controllable atmosphere rotary hearth furnace process is suitable for various kinds of materials; and the temperature in a furnace hearth is uniform, the automation degree of equipment is high, workers operate simply and conveniently, and sponge iron meeting the demand of steel-making can be produced.

Description

technical field [0001] The invention relates to a method for producing reduced iron, which adopts a two-step process of a controlled atmosphere rotary hearth furnace and can use iron-containing oxides such as iron concentrate powder / high-grade lump ore / rolled steel scale (Fe≥68%) Produce ground reduced iron that meets the needs of the steel industry. Background technique [0002] Direct reduced iron, also known as sponge iron, is a low-carbon porous substance formed by reducing iron-containing oxides such as iron concentrate powder / high-grade lump ore / rolled steel scale in a reduction furnace. Its chemical composition is stable and its impurity content is low. It is mainly used as a raw material for electric furnace steelmaking, and also as a coolant for converter steelmaking. In recent years, due to the development of iron and steel products in the direction of small and light weight, advanced functions, and composites, the proportion of non-metallic materials and non-ferr...

AI Technical Summary

Problems solved by technology

[0004] The development of rotary hearth furnace technology in China also has a certain history. In recent years, a number of rotary hearth furnace devices have been built successively to process special iron-containing materials such as compound ore, low-grade refractory iron ore, zinc-containing dust from iron and steel plants, and laterite ore. Good results have been obtained, but the traditional rotary hearth furnace has a large difference in the reduction temperature in the furnace, the reduction temperature is uneven, and the atmosphere in the furnace is poorly adjustable, resulting in the production of direct reduced iron with low iron content (TFe<85% ), high sulfur content (S: 0.1% ~ 0.2%) and other shortcomings, it is difficult to be directly used as DRI for steelmaking. Accidents such as material leakage and non-feeding often occur in the feeder

Images