Low Carbon Ferroalloy Production via Integrated Converter Vacuum Decarburization

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Solution Overview

Problem

Conventional methods for producing ferroalloys with low carbon content, such as chromium and manganese alloys, are inefficient in terms of treatment time and material consumption, and require multiple process stages with significant energy expenditure.

Innovation Solution

The method involves adding oxygen to the melt before completing the converter process, allowing for slag formation and subsequent reduction in the vacuum process, where high temperatures and deep vacuum conditions facilitate complete decarburization without external oxygen supply, integrating the converter and vacuum processes in a single metallurgical vessel.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional converter process with slag reduction is used, then carbon content can be reduced, but treatment time increases and energy consumption increases

Engineering Contradiction:
Improvecarbon contentVSAvoidtreatment time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The invention extracts and eliminates the slag reduction step from the conventional converter process sequence. By removing this intermediate step and proceeding directly from converter to vacuum treatment, the process reduces treatment time while achieving the same carbon content reduction through the combined converter-vacuum process.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention merges the converter process and vacuum process into an integrated flow where the converter produces a specific type of slag that is directly suitable for vacuum treatment. This merging eliminates the need for separate slag reduction operations and enables continuous processing.

Inventive Principle:
Principle #5Merging (Combining)

2Manufacturing precision

If conventional converter process with slag reduction is used, then carbon content can be reduced, but energy consumption increases

Engineering Contradiction:
Improvecarbon contentVSAvoidenergy consumption
Core Design Contradiction:
Manufacturing precisionVSUse of energy by moving object

Solution Approach 1:

The invention extracts and eliminates the energy-intensive slag reduction step from the process sequence. By removing this step and proceeding directly to vacuum treatment, the process reduces overall energy consumption while maintaining effective carbon reduction through the integrated converter-vacuum approach.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention ensures continuous useful action by eliminating idle or redundant steps between converter and vacuum treatment. The slag from the converter is directly utilized in the vacuum process without intermediate reduction, maintaining process continuity and reducing energy waste.

Inventive Principle:
Principle #20Continuity of useful action

3Manufacturing precision

If multiple process stages are used, then carbon content can be reduced to below 0.1%, but process complexity increases

Engineering Contradiction:
Improvecarbon contentVSAvoidprocess complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The invention merges multiple process stages into a streamlined sequence where the converter process is optimized to produce slag specifically suited for vacuum treatment. This integration reduces process complexity by eliminating intermediate steps while maintaining the multi-stage nature necessary for achieving carbon content below 0.1%.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The invention applies preliminary action by optimizing the converter process to produce slag with specific characteristics (high basicity, high CaF2 content) that are pre-conditioned for the subsequent vacuum treatment. This preliminary preparation simplifies the overall process by ensuring the slag is ready for direct vacuum processing without additional reduction steps.

Inventive Principle:
Principle #10Preliminary action

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

This approach significantly reduces treatment time, minimizes inert gas consumption, and lowers refractory material usage, achieving carbon contents below 0.1% with improved energy efficiency and reduced slag formation.

Implementation Method 1

a melt of the ferroalloy is first primarily decarburized and treated by adding oxygen in a converter process

Methodology Applied
Scientific EffectOxidation: Oxidation

Implementation Method 2

the melt thus prepared is refined to the low carbon content in a subsequent vacuum process

Methodology Applied
Scientific EffectVacuum: Vacuum

Implementation Method 3

oxygen is added to the melt before the end of the converter process, forming slag

Methodology Applied
Scientific EffectOxidation: Oxidation

Implementation Method 4

a reduction of the slag only takes place in the subsequent vacuum process

Methodology Applied
Scientific EffectReduction: Reduction

Data Source

PatentEP4056721A1Method for producing a ferrous alloy with low carbon content
Publication Date: 2022.09.14 SMS GROUP GMBH
  • EP4056721A1 patent drawingFigure 1
  • EP4056721A1 patent drawingFigure 2
  • EP4056721A1 patent drawingFigure 3

AI summary

The invention relates to a process for producing a ferroalloy with a low carbon content, in particular a chromium alloy or a manganese alloy with a carbon content of less than 0.1%, in which a melt of the ferroalloy is first treated by adding oxygen in a converter process, and then the prepared melt is decarburized in a subsequent vacuum process. To shorten the treatment time of the melt and also reduce the consumption of the required raw materials, the invention provides that oxygen is added to the melt before the end of the converter process, forming slag. No reduction of the slag takes place in the converter process, and that slag reduction occurs only in the subsequent vacuum process.