A production method of flux-based composite carbon-containing pellets for blast furnaces

Abstract

The invention provides a production method of fluxed composite carbon-containing pellets used in a blast furnace, wherein a mixture A is composed of 65-80% of iron ore concentrate, 1-2% of a binding agent and 10-20% of a carbon-containing material with addition of a flux to enable the ratio of (CaO+MgO) / SiO2 of the mixture A to be 1-1.4. The mixture A is added with water and is mixed uniformly to form self-fluxing pellet cores being 5-7 mm in granularity. A mixture B is composed of 75-85% of the iron ore concentrate, 1-2% of the binding agent and 5-15% of the carbon-containing material, wherein a flux is added until the ratio of (CaO+MgO) / SiO2 of the mixture A is 0.2-0.5. The production method includes the steps of placing the self-fluxing pellet cores in a pelletizer, adding the mixture B for performing pelletizing continuously to obtain raw carbon-containing pellets being 10-16 mm in granularity, and roasting the raw carbon-containing pellets to obtain the fluxed composite carbon-containing pellets. The method solves the problems of roast bonding of the fluxed pellets and internal self-reduction delay of the carbon-containing pellets, enables the alkalinity and reduced carbon in the pellets to be distributed in a gradient manner, can greatly improve high-temperature metallurgical performances of the carbon-containing pellets, can reach 2081 N / pellet in compressive strength and is 40% in metallization rate.

Description

Technical field [0001] The invention belongs to the technical field of ironmaking raw material production, and particularly relates to a method for producing flux-based composite carbon-containing pellets for blast furnaces. Background technique [0002] Blast furnace ironmaking is a key process for energy saving and emission reduction in the steel process. In the current situation of increasingly stringent requirements for energy conservation and emission reduction in the world, there is an urgent need to develop innovative technologies that can greatly save energy and reduce pollutant emissions. In addition, in recent years, high-quality raw fuel resources have become increasingly scarce, and in the case of rising raw fuel prices, it is necessary to develop new charge materials to flexibly deal with this situation. Carbon-containing pellets are a new type of blast furnace charge developed for this need. [0003] Carbon-containing pellets are a kind of pellets with a certain con...

AI Technical Summary

Problems solved by technology

[0009] The invention provides a production method of flux-based composite carbon-containing pellets for blast furnaces, aiming to produce flux-based composite carbon-containing pellets with double alkalinity and gradient distribution of carbon-containing raw materials in the inner and outer layers of the pellets through two pelletizations to solve the problem of flux-based pellet roasting bonding and internal self-reduction delay of carbon-containing pellets