Desulfurization Slag Treatment via High-Temp Oxidation
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Solution Overview
Problem
Current methods for processing desulfurization slag are economically inefficient and allow sulfur to be reintroduced into the pig iron production cycle, leading to landfill issues and environmental concerns.
Innovation Solution
A method involving heating desulfurization slag above 1400°C in a rotary converter with an oxidizing atmosphere, using a separate oxygen lance for sufficient turbulence and excess oxygen to release sulfur as SO2, which is then converted into sulfuric acid, allowing for the reuse of iron content in the slag while minimizing sulfur return to pig iron production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If desulfurization slag is reused in pig iron production, then iron content is recovered and utilized, but sulfur is reintroduced into the production cycle causing environmental problems
Solution Approach 1:
The patent extracts sulfur from the desulfurization slag through oxidation treatment before the slag is reused in pig iron production. By removing the harmful sulfur component while retaining the iron-bearing slag for reuse, the process prevents sulfur reintroduction into the production cycle while maintaining iron recovery benefits
Solution Approach 2:
The patent selectively discards sulfur from the desulfurization slag through oxidation and gas-phase removal, while recovering and reusing the iron-containing slag material in pig iron production. This separation allows beneficial iron recovery while eliminating harmful sulfur
2Object-generated harmful factors
If wet-chemical processing methods are used to treat desulfurization slag, then sulfur removal is achieved, but processing costs become very expensive
Solution Approach 1:
The patent changes the processing parameters from wet-chemical methods to high-temperature oxidation (above 1400°C) in a basic oxygen converter. This parameter change transforms the treatment approach into a more cost-effective process that utilizes the existing steelmaking infrastructure and achieves sulfur removal through oxidation rather than expensive chemical treatments
Solution Approach 2:
The patent replaces wet-chemical processing systems with a thermal oxidation process using a basic oxygen converter. This substitution leverages mechanical/thermal energy and existing steelmaking equipment instead of expensive chemical reagents and wet-processing infrastructure
3Object-generated harmful factors
If desulfurization slag is heated to high temperatures above 1400°C, then sulfur is effectively removed as SO2, but energy consumption increases
Solution Approach 1:
The patent merges the desulfurization slag treatment process with the existing basic oxygen converter used for pig iron oxidation. By combining sulfur removal from slag with the primary function of the converter, the process utilizes the same high-temperature environment and oxygen supply system, thereby reducing additional energy requirements compared to dedicated heating processes
Solution Approach 2:
The basic oxygen converter serves multiple functions: it oxidizes sulfur from the desulfurization slag, processes pig iron, and provides the high-temperature environment needed for slag treatment. This multi-functionality reduces the need for separate energy-intensive heating equipment
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 process effectively removes sulfur from the slag, enabling its recycling and production of sulfuric acid, reducing landfill needs and sulfur input in pig iron production, with the slag having a guaranteed sulfur content of less than 0.1% by mass.
Implementation Method 1
heating desulfurization slag above 1400°C in a rotary converter with an oxidizing atmosphere, using a separate oxygen lance for sufficient turbulence and excess oxygen to release sulfur as SO2
Implementation Method 2
using a separate oxygen lance for sufficient turbulence
Data Source
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AI summary
The invention relates to a method for treating desulfurization slag. In said method, desulfurization slag obtained from a pig iron desulfurization process is fed to a suitable unit by liquefying the desulfurization slag at a minimum temperature of 1400 °C, the unit in which the treatment is carried out at slightly oxidizing conditions ensures that the slag is thoroughly mixed, and the released SO2 is collected from the roasting gas and is made available for further use.