Indirect Cooling of Black Slag in Steel Production

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Solution Overview

Problem

Current methods for treating black slag generated in steel production are lengthy, require extensive handling and storage spaces, involve high costs, and necessitate complex leachate treatment, while maintaining high quality and safety standards.

Innovation Solution

A method and apparatus for indirectly cooling black slag immediately after its generation using a rotating tubular reactor with indirect heat exchange, reducing handling and storage needs, and achieving rapid cooling to stabilize mineral structures without free lime formation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If black slag is cooled by direct water contact in a collection area, then cooling efficiency is improved, but leachate pollution is generated requiring complex treatment plants

Engineering Contradiction:
Improvecooling efficiencyVSAvoidleachate pollution
Core Design Contradiction:
TemperatureVSObject-generated harmful factors

Solution Approach 1:

The patent introduces an intermediary cooling medium (air or water) that indirectly cools the slag through heat exchange surfaces, preventing direct contact between water and slag, thus eliminating leachate generation while maintaining cooling efficiency

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the mechanical direct-contact cooling system with a thermal field-based indirect cooling system using heat exchange surfaces, eliminating the need for leachate collection and treatment infrastructure

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If black slag is stored for 3-6 months in a large storage area, then complete extinguishing of residual quicklime is achieved, but extensive space and handling means are required

Engineering Contradiction:
Improvecomplete extinguishing of quicklimeVSAvoidstorage area extension
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

The patent applies preliminary rapid cooling treatment to the slag immediately after discharge, achieving quicklime stabilization in minutes rather than months, thereby eliminating the need for large long-term storage areas

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent rushes through the traditional 3-6 month storage period by implementing intensive rapid cooling that achieves complete quicklime extinguishing in minutes, skipping the lengthy waiting period and associated storage space requirements

Inventive Principle:
Principle #21Skipping (Rushing through)

3Ease of manufacture

If multiple handling means are used to transport slag between areas, then treatment process is completed, but handling costs and treatment time are increased

Engineering Contradiction:
Improvetreatment process completionVSAvoidtreatment time
Core Design Contradiction:
Ease of manufactureVSLoss of time

Solution Approach 1:

The patent merges the cooling and stabilization operations into a single integrated rapid cooling process, eliminating the need for separate storage, handling, and waiting operations, thereby reducing both time and handling costs

Inventive Principle:
Principle #5Merging (Combining)

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 method significantly reduces treatment time and space requirements, eliminates the need for leachate treatment plants, and produces a stable, high-quality secondary raw material with improved energy efficiency and safety.

Implementation Method 1

A method and apparatus for indirectly cooling black slag immediately after its generation using a rotating tubular reactor with indirect heat exchange

Methodology Applied
Scientific EffectIndirect heat exchange: Heat Exchanger

Data Source

PatentEP4301881B1An improved method for the treatment of the black slag
Publication Date: 2025.11.12 TRUYOINS SRL
  • EP4301881B1 patent drawingFigure 1
  • EP4301881B1 patent drawingFigure 2~3
  • EP4301881B1 patent drawingFigure 4

AI summary

Method for the treatment of black slag (1), which contains lime (CaO) or lime- based compounds, and which is generated in an electric furnace (2) to produce steel starting from scrap, characterized by the fact that said black slag is indirectly cooled, immediately after its exit from said electric furnace (2) or after its collection in a cauldron (3), for a period of time between about 10 minutes and about 45 minutes, preferably between about 10 minutes and about 30 minutes.