applied
sciencesArticle
Quantitative Analysis of Pig Iron from Steel Industry
by Handheld Laser-Induced Breakdown Spectroscopy
and Partial Least Square (PLS) Algorithm
Giorgio S. Senesi 1,* , Olga De Pascale 1, Aldo Bove 2 and Bruno S. Marangoni 3
1 Istituto per la Scienza e Tecnologia dei Plasmi (ISTP-CNR)-Sede di Bari, 70126 Bari, Italy;
olga.depascale@istp.cnr.it2 Primary and Environmental Laboratories, ArcelorMittal Italia S.p.A., Taranto Steelworks,
74123 Taranto, Italy; aldo.bove@gruppoilva.com3 Physics Institute, Federal University of Mato Grosso do Sul, Campo Grande, MS 79070-900, Brazil;
bruno.marangoni@ufms.br
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Correspondence: giorgio.senesi@cnr.it; Tel.: +39-08-0592-9505
Received: 12 October 2020; Accepted: 25 November 2020; Published: 27 November 2020
Abstract: One of the main objectives in the steel production process is to obtain a blast furnace pig
iron of good quality and at the lowest possible cost. In general, the quality of pig iron is evaluated
on the basis of its chemical composition determined by X-ray fluorescence laboratory equipment.
In the present study, the performance of a handheld (h) laser-induced breakdown spectroscopy (LIBS)
instrument in the identification and the quantification of the relevant elements C, Mn, P, Si, and Ti
in forty-six blast furnace pig iron samples was tested successfully. The application of two different
models, i.e., univariate and multivariate partial least square (PLS) calibration and validation, to the
whole LIBS data set showed that the latter approach was much more efficient than the former one in
quantifying all elements considered, especially Si and Ti.
Keywords: handheld LIBS; pig iron; steel; PLS
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Introduction
The main metallic materials and intermediate products involved in iron and steel industry include
pig iron, cast iron, carbon steel, stainless steel, and tool steel, all of which require continuous, accurate,
and precise analyses to keep the entire production process under control. In particular, pig iron consists
of a carbon-rich intermediate product resulting from a mixture of iron ore, coke, and limestone burnt
together in a blast furnace, which is then refined into steel in an oxygen furnace [1,2]. The main goal of
the production process is to obtain pig iron of good quality at the lowest possible cost. Many factors
affect the quality of pig iron, among which are the quality of ferrous burden materials and coke as
well as the fuels and the methods used in the blast furnace process [3]. In particular, the content of the
elements Si, Mn, P, and S, which depend on their abundance in ferrous burden materials [3], and Ti,
which critically affects its precipitation with saturated carbon [4], have great importance for the quality
of pig iron. According to relevant customer requirements and standards, the chemical composition
of pig iron should include, besides the basic element, Fe, and a high C content, a number of other
alloying elements that are Si at 0.50–0.80% wt., Mn at >0.20% wt., P at <0.11% wt., and S at <0.030%
wt. for the production of rail steel and 0.14% wt. for other kinds of steel [3,5]. However, every steel
plant around the world requires a different elemental composition. For example, the best performance
of the blast furnace operating at the ArcelorMittal Italia S.P.A. steel plant located in Taranto, Italy,
where the samples examined in this work were collected, is achieved at an optimal Si content in pig
iron of 0.60% wt.
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