Quicklime Carburizer Composition for High-Ash Molten Iron Charging

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Solution Overview

Problem

The use of carbon materials with high ash content in carburization processes leads to reduced carburization rates due to the formation of an ash film on the carbonaceous surface, which impedes contact with molten iron, especially under conditions of weak agitation intensity, and there is a need for a cost-effective solution to enhance the carburization efficiency.

Innovation Solution

A carburizer comprising a mixture of quicklime and carbon material with specific ash content ratios, formulated to modify the ash film composition and increase the reaction efficiency by adding quicklime to the carbon material, thereby promoting carburization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a carbon material with high ash content is used as carburizer, then cost is reduced, but carburization rate becomes significantly lower

Engineering Contradiction:

ImprovecostVSAvoidcarburization rate

Core Design Contradiction:

Ease of manufactureVSProductivity

Solution Approach 1:

The patent introduces a fluxing agent as an intermediary substance that reacts with ash components to form a liquid film. This liquid film acts as a mediator that prevents ash from coating the carbon material surface, thereby enabling high-ash carbon materials to achieve effective carburization rates comparable to low-ash materials.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the chemical composition parameters of the carburizer by adding fluxing agents (such as CaF2, SiO2, Al2O3, TiO2, B2O3, or ZnO) in specific proportions (0.1-10 mass%). This parameter modification transforms the ash film from a harmful coating into a beneficial liquid film that enhances carbon transfer efficiency.

Inventive Principle:

Principle #35Parameter changes

2Ease of manufacture

If ash content in carbon material is increased, then cost is suppressed, but carburization efficiency decreases due to ash film formation

Engineering Contradiction:

ImprovecostVSAvoidcarburization efficiency

Core Design Contradiction:

Ease of manufactureVSProductivity

Solution Approach 1:

The patent converts the harmful ash film into a beneficial liquid film by adding fluxing agents. The ash components (SiO2, Al2O3, CaO, etc.) that would normally form a coating are transformed into a liquid film through fluxing agent reactions, which actually enhances the contact between carbon material and molten iron, turning the harmful ash into a useful component.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent creates a composite carburizer material combining carbon material with high ash content and fluxing agents in specific ratios. This composite structure allows the harmful ash components to work together with the fluxing agents to form a beneficial liquid film, achieving both cost reduction and high carburization efficiency.

Inventive Principle:

Principle #40Composite materials

3Ease of manufacture

If carbon material with high ash content is used, then material cost is reduced, but reaction efficiency is lowered due to ash coating

Engineering Contradiction:

Improvematerial costVSAvoidreaction efficiency

Core Design Contradiction:

Ease of manufactureVSPower

Solution Approach 1:

The fluxing agent serves as a chemical intermediary that facilitates the reaction between carbon material and molten iron. It modifies the ash film properties to create a liquid film that enhances mass transfer, thereby improving reaction efficiency despite using high-ash, low-cost carbon materials.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

By adjusting the chemical composition parameters through fluxing agent addition (0.1-10 mass%), the patent changes the physical and chemical properties of the ash film from a solid coating to a liquid film, significantly improving reaction efficiency and carbon transfer rates.

Inventive Principle:

Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The modified carburizer achieves improved carburization rates by altering the ash film composition, reducing sulfur concentration, and enhancing the contact area between molten iron and carbon material, resulting in cost savings and increased efficiency.

Implementation Method 1

the formation of an ash film on the carbonaceous surface, which impedes contact with molten iron

Methodology Applied

Scientific EffectAsh film formation:

Implementation Method 2

adding quicklime to the carbon material, thereby promoting carburization

Methodology Applied

Scientific EffectQuicklime modification:

Implementation Method 3

enhancing the contact area between molten iron and carbon material

Methodology Applied

Scientific EffectContact area enhancement:

Implementation Method 4

addition of a solid carbon material to molten iron as a carburizer to carburize the molten iron

Methodology Applied

Scientific EffectCarburization: Carburizing

Data Source

PatentUS20260043120A1Carburizer and carburization method using the same

Publication Date: 2026.02.12 NIPPON STEEL CORPORATION

AI summary

A carburizer, which effects carburization with respect to molten iron accommodated in an electric furnace or a ladle, includes a mixture of quicklime and a carbon material having an ash content of from 5 mass % to 18 mass %, and satisfies the conditions 0.6≤(mc+Mc)/ms≤2.7 and 0.7≤(mc+Mc)/ma≤6.5. A method of carburization uses this carburizer. Here, mc represents the mass of CaO in the carbon material, ms represents the mass of SiO2 in the carbon material, ma represents the mass of Al2O3 in the carbon material, and Mc represents the mass of the quicklime.