Aluminothermic Gradient Reduction for Titanium Alloy Preparation

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Solution Overview

Problem

Conventional methods for preparing titanium alloys, such as vacuum fusion casting and powder metallurgy, are energy-intensive and costly due to the need for titanium sponge production, and the aluminothermic reduction method struggles with incomplete reduction of TiO2 and control of aluminum content.

Innovation Solution

A method involving aluminothermic self-propagating gradient reduction and slag-washing refining, using rutile, high-titanium slags, or titanium dioxide as raw materials, with a gradient feeding process and slag-washing refining to achieve complete reduction and controlled aluminum content in titanium alloys.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional vacuum fusion casting or powder metallurgy methods are used to prepare titanium alloys, then the alloy quality and performance can be ensured, but the energy consumption is high and the production cost is high due to the complex titanium sponge production process

Engineering Contradiction:
Improvealloy qualityVSAvoidenergy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The invention segments the reduction process into multiple stages with different oxygen partial pressures. The first stage uses high oxygen partial pressure for initial reduction, and the second stage uses low oxygen partial pressure for complete reduction, allowing each stage to operate under optimized conditions and reducing total energy consumption

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention changes the oxygen partial pressure parameter during the reduction process. By controlling the oxygen partial pressure to first be high and then be low, the method optimizes the reduction efficiency at different stages, achieving complete TiO2 reduction with lower overall energy input compared to conventional single-stage methods

Inventive Principle:
Principle #35Parameter changes

2Reliability

If conventional vacuum fusion casting or powder metallurgy methods are used to prepare titanium alloys, then the alloy quality and performance can be ensured, but the technological process is complex and the production cost is high

Engineering Contradiction:
Improvealloy qualityVSAvoidprocess complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention merges the reduction process and alloying process into a single integrated aluminothermic reduction reaction. Titanium dioxide, aluminum powder, and alloying element oxides are reduced simultaneously in one process, eliminating the need for separate titanium sponge production and alloying steps, thereby simplifying the overall technological process

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The aluminothermic reduction reaction is self-propagating and self-heating, utilizing the exothermic nature of the reaction to maintain the required temperature for complete reduction without external heating, simplifying the process control and reducing equipment complexity

Inventive Principle:
Principle #25Self-service

3Use of energy by moving object

If aluminothermic reduction method is used to prepare titanium alloys, then the energy consumption is reduced and the process is simplified, but the reduction of TiO2 is incomplete and the aluminum content cannot be controlled

Engineering Contradiction:
Improveenergy consumptionVSAvoidaluminum content control
Core Design Contradiction:
Use of energy by moving objectVSManufacturing precision

Solution Approach 1:

The invention segments the reduction process into two stages with different oxygen partial pressures. The first stage with high oxygen partial pressure prevents excessive aluminum reduction, while the second stage with low oxygen partial pressure completes the TiO2 reduction, thereby controlling the final aluminum content in the alloy

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention uses oxygen partial pressure as a feedback control parameter. By monitoring and adjusting the oxygen partial pressure during the reduction process, the method ensures complete TiO2 reduction while preventing excessive aluminum content, achieving precise control of the alloy composition

Inventive Principle:
Principle #23Feedback

4Use of energy by moving object

If aluminothermic reduction method is used to prepare titanium alloys, then the energy consumption is reduced and the process is simplified, but the reduction of TiO2 is incomplete

Engineering Contradiction:
Improveenergy consumptionVSAvoidreduction completeness
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The invention segments the reduction process into two stages: first stage with high oxygen partial pressure for initial reduction, and second stage with low oxygen partial pressure for complete reduction. This segmentation ensures that TiO2 is completely reduced while maintaining energy efficiency

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention changes the oxygen partial pressure parameter during the reduction process. By controlling the oxygen partial pressure to first be high and then be low, the method optimizes the reduction efficiency at different stages, achieving complete TiO2 reduction with lower overall energy input

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

This method reduces energy consumption, simplifies the process, and effectively controls aluminum content, resulting in high-quality titanium alloys with improved properties.

Implementation Method 1

aluminothermic self-propagating gradient reduction

Methodology Applied
Scientific EffectAluminothermic reduction: Redox Reactions

Implementation Method 2

self-propagating reaction

Methodology Applied
Scientific EffectExothermic reaction: Exothermic Reaction

Implementation Method 3

melt separation

Methodology Applied
Scientific EffectDensity separation: Density Gradient

Implementation Method 4

slag-washing refining

Methodology Applied
Scientific EffectSlag washing refining: Purification

Implementation Method 5

cooling

Methodology Applied
Scientific EffectSolidification: Freezing

Data Source

PatentUS11060166B2Method for preparing titanium alloys based on aluminothermic self-propagating gradient reduction and slag-washing refining
Publication Date: 2021.07.13 NORTHEASTERN UNIV CHINA

AI summary

The invention relates to a method for preparing titanium alloys based on aluminothermic self-propagating gradient reduction and slag-washing refining, and belongs to the technical field of titanium-aluminum alloys. The method comprises the following steps of pre-treating raw materials, weighing the raw materials in the mass ratio of rutile or high-titanium slags or titanium dioxide to aluminum powder to V2O5 powder to CaO to KClO3 being 1.0:(0.60-0.24):(0.042-0.048):(0.12-0.26):(0.22-0.30), performing an aluminothermic self-propagating reaction in a gradient feeding manner to obtain high-temperature melt, performing a gradient reduction melting, performing heat insulation and separating the melt after the feeding is completed, then adding CaF2—CaO—TiO2—V2O5 based refining slags into the high-temperature melt, performing slag washing refining, and finally removing slags to obtain titanium alloys. This method has the advantages including short flow, low energy consumption, easy operation, easy control on Al and V contained in alloys, and so on.