OXYFINES Technique for Upgrading Zinc Containing Blast Furnace Sludge—Part 2: System Analysis

Katarina Lundkvist,Sara Rosendahl,Fredrik Nyman,Kristofer Bölke,Lennart Gustavsson,Anita Wedholm,Daniel Söderström

doi:10.3390/met10111471

Abstract

Integrating novel technology in production systems for the upgrading and further use of residual materials is a potential way of improving the resource efficiency. Assessing technology integration prospects, by performing system analysis, assists in the forecasting of effects and opportunities for different concepts. Based on pilot trials results, using Linde’s OXYFINES technique for upgrading zinc containing blast furnace sludge, a system analysis was performed on the prospects of integrating an OXYFINES concept in an iron and steel production route. The calculations were made based on one option for a full-scale OXYFINES concept for indicating the effects on the blast furnace zinc load, raw material consumption, energy use and carbon dioxide emissions from using the OXYFINES sinter product as a raw material in blast furnace ironmaking or in the basic oxygen furnace steelmaking. The summarised system analysis results showed that the most advantageous metallurgical, environmental, and economic potential was realised in the calculations of using the sinter in the basic oxygen furnace. However, the sinter was found as well suitable for use in the blast furnace when considering mainly the metallurgical and the economic effects.

Highlights

Decreased residual materials generation and extending the recycling and utilisation has gradually become more important
The system analysis results indicate the effects on blast furnace (BF) zinc load, raw materials consumption, energy use, and CO2 emission from using the OXYFINES sinter product as a raw material in BF ironmaking or alternatively in the basic oxygen furnace (BOF) steelmaking processes
A decreased BOF slag use in the BF with some 1.6 kg/tHM or about 3.2 ktonne/a to prevent the phosphorous content in the hot metal (HM) exceeding its maximum level of 0.035%

Summary

Introduction

Decreased residual materials generation and extending the recycling and utilisation has gradually become more important. Commission’s Circular Economy Package are promotors of the further strive for increased resource efficiency [1,2]. Avoiding landfill and making use of valuable contents of residual materials, thereby reducing the use of virgin raw materials entails positive effects on economy, space, and environment. In ore-based steel production at the SSAB steel plant in Luleå, Sweden, blast furnace (BF) sludge is one residual currently put on landfill or long-term storage. BF sludge contains substantial amounts of iron and carbon, all freshly generated sludge is deposited in settling ponds at the steel production site. The main reason for this is the zinc content in the sludge which due to process related restrictions makes it unsuitable for a direct recovery to the existing in-plant processes

Objectives

Methods

Results

Discussion

Conclusion