Teresa Annunziata Branca

A way to reduce environmental impact of ladle furnace slag

Abstract In the last decades the European steel industry has made continuous efforts to reduce residues and byproducts and to increase recycling in order to reduce its environmental impact. While some steelmaking slags have been widely characterised and, to a certain extent reused, ladle furnace (LF) slag is used in different applications because of its specific properties. The main purpose of the case study presented in this paper concerns the reduction of potential LF slag environmental impacts, because of its intrinsic physicochemical properties. During the handling and cooling of LF slag, it disintegrates into a powder due to instability of the dicalcium silicate, causing an increase in dust emissions to the environment. The approach presented in this paper aims to reduce this phenomenon in order to achieve a more sustainable solution in term of reduction of powder dispersion in the environment, of costs saving and of nuisance reduction in the surroundings areas.

Possible Uses of Steelmaking Slag in Agriculture: An Overview

Over the past decades, the steel production has increased and, consequently, the higher volumes of by-products and residues generated have driven to the reuse of these materials in an increasingly efficient way. In recent years new technologies have been expanded, and some of them are still under developing, in order to improve the recovery rates of slags. On this subject material separation technologies and carbon sequestration could dramatically reduce CO2 emissions from steelmaking processes. On the other hand, the increase of slags recovery and use in different fields of application, such as in agriculture, allowed to reduce landfill slags and to preserve natural resources. In addition to the environmental achievements, these practices produced economic benefits, by providing sustainable solutions that can allow the steel industry to achieve its ambitious target of “zero-waste” in the incoming years (worldsteel, 2008).

Process Integration in Energy and Carbon Intensive Industries Through Exploitation of Optimization Techniques and Decision Support

Process industries show an ever-increasing interest in reducing their environmental impact and energy consumption as well as maintaining an acceptable profit. This is particularly true for industries such as the steel one, which is among the highest energy consumers worldwide. Process modelling and optimization are techniques by which this problem can be effectively addressed, particularly if the overall system is optimised as a whole. In this article we describe a model for a discrete dynamic optimization of the process gas network in an integrated steel plant. The main sub-plants are modelled in order to calculate mass and energy balances in different scenarios of operation. The scenarios are then exploited within a multi-objective optimization problem, where cost and CO2 emissions are simultaneously minimised. The optimization is carried out by exploitation of evolutionary algorithms that enable a flexible problem formulation and to effectively generate a set of different trade-off solutions. Application of the model to an industrial case study results in an interesting potential for reduction of CO2 emissions and costs. The described optimisation model is embedded in a more general software tool to help the plant managers in their daily decision-making process.