Complex Reducing Agent Slag Viscosity Control

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Solution Overview

Problem

Current methods for reducing slag in iron-making and steel-making processes do not achieve optimal reduction efficiency, particularly in terms of valuable metal recovery, due to suboptimal composition ratios and utilization of reducing agents.

Innovation Solution

A method involving the use of complex reducing agents with specific composition ratios of aluminum, calcium, silicon, carbon, and iron, along with lime as a slag forming agent, to achieve a target composition ratio of calcium oxide, silicon dioxide, and aluminum oxide in the slag, thereby minimizing viscosity and melting point and maximizing reduction efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional reducing agents are used in standard proportions, then the slag reduction process can proceed, but the reduction efficiency and valuable metal recovery remain suboptimal

Engineering Contradiction:
Improvereduction efficiencyVSAvoidvaluable metal recovery
Core Design Contradiction:
ProductivityVSLoss of substance

Solution Approach 1:

The patent applies parameter changes by precisely controlling the chemical composition ratios of the reducing agent (Al: 7.5-37%, Ca: 19.5-28.5%, Si: 37-55.5%, C: 0.2-0.4%, Fe: 6.3-9.8%) and the target slag composition (CaO: 39.5-40.5%, SiO2: 39.5-40.5%, Al2O3: 19.5-20.5%). This optimization of compositional parameters maximizes the reduction efficiency and valuable metal recovery from slag, transforming conventional suboptimal reduction into a highly efficient process.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs a composite reducing agent containing multiple elements (Al, Ca, Si, C, Fe) in specific proportions rather than using a single reducing agent. This composite approach allows synergistic effects where different components contribute to various aspects of the reduction process, improving overall reduction efficiency and metal recovery while minimizing harmful byproducts.

Inventive Principle:
Principle #40Composite materials

2Productivity

If the slag composition is not optimized, then the reduction process can occur, but the viscosity and melting point remain high, reducing reduction efficiency

Engineering Contradiction:
Improvereduction efficiencyVSAvoidmelting point
Core Design Contradiction:
ProductivityVSTemperature

Solution Approach 1:

The patent optimizes the slag composition parameters to achieve a target composition of CaO (39.5-40.5%), SiO2 (39.5-40.5%), and Al2O3 (19.5-20.5%). This precise parameter control results in slag with minimized viscosity and melting point, creating optimal conditions for efficient reduction and rapid phase separation, thereby significantly improving reduction efficiency.

Inventive Principle:
Principle #35Parameter changes

3Loss of substance

If non-optimized reducing agent composition is used, then reduction can proceed, but the phase separation is slow and metal recovery is reduced

Engineering Contradiction:
Improvemetal recoveryVSAvoidphase separation time
Core Design Contradiction:
Loss of substanceVSLoss of time

Solution Approach 1:

The patent optimizes the reducing agent composition parameters (Al: 7.5-37%, Ca: 19.5-28.5%, Si: 37-55.5%, C: 0.2-0.4%, Fe: 6.3-9.8%) to achieve rapid and complete phase separation. This optimized composition facilitates faster reaction kinetics and more efficient metal-slag separation, reducing processing time while maximizing metal recovery and minimizing losses.

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 approach enhances the recovery of valuable metals by optimizing the reduction process, efficiently utilizing various reducing agents, and reducing costs by achieving the lowest viscosity and melting point at the target composition ratio, thereby accelerating phase separation and improving metal recovery.

Implementation Method 1

supplying an optimal reducing agent into slag generated from an iron-making or steel-making process to improve the reduction effect of slag

Methodology Applied
Scientific EffectChemical reduction: Reduction

Implementation Method 2

heating the mixture sufficiently for an aluminothermical reaction to start if Al is present as reducing agent above the melting point to reduce the smelter slag to a metal alloy

Methodology Applied
Scientific EffectAluminothermical reaction: Exothermic Reaction

Implementation Method 3

separating the metal alloy from the secondary slag

Methodology Applied
Scientific EffectPhase separation: Phase Change

Data Source

PatentEP2811038B1Method for reducing slag
Publication Date: 2019.02.27 HYUNDAE STEEL CO LTD
  • EP2811038B1 patent drawingFigure 1
  • EP2811038B1 patent drawingFigure 2
  • EP2811038B1 patent drawingFigure 3

AI summary

Disclosed herein is a method of reducing slag, including the steps of: examining the components of slag to be reduced, and setting a target composition ratio after reduction; determining the mixing ratio and input amount of a complex reducing agent of a plurality of reducing agents in accordance with the set target composition ratio to determine the complex reducing agent; and supplying the complex reducing agent into molten slag to reduce the slag. The method is advantageous in that the reduction efficiency of slag can be maximized, various kinds of reducing agents can be efficiently used, and the recovery amount of valuable metals can be increased, thus reducing cost.