## 1 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. Wavelength-dispersive X-ray fluorescence (WDXRF) spectrometry is a well-established analytical technique in iron and steel industry and is routinely used to analyse raw materials, sinters, slags, and the elemental composition of cast iron and steels when coupled with optical emission spectrometry (OES) [2]. Although this technique can achieve great accuracy and precision, the instrumentation is not portable and is quite expensive. Furthermore, in iron and steel industry, the samples to be analysed must be representative of an enormous body of material, such as a shipload of iron ore, a stockpile of raw material, and intermediate and final products from the plant. This aspect involves a very marked reduction in size in deriving a laboratory-sized sample of a few kg from many thousands of tons of original material, thus it is important to implement an analytical procedure that can minimize the errors associated with sampling [2]. In recent years the demand for lower limits of detection (LOD), improved analytical reliability, strict control of alloy composition, and capability to place the analytical instrumentation as close as possible to the process so to facilitate and speed up any corrective actions during production have prompted manufacturers to design more sensitive and flexible instruments that could be easily incorporated into transportable equipment. Laser-induced breakdown spectroscopy (LIBS) has been used widely as a versatile alternative analytical technique in the steel industry, e.g., for iron ore selection, process control, and iron slag analysis [6; 7; 8; 9; 10]. Furthermore, in the last years, the technique has progressed so to allow the development of handheld, self-contained commercial instruments able to analyse samples of various nature directly on site [11; 12; 13; 14]. Although a set of recent manufacturer application notes have illustrated how the handheld (_h_) LIBS analysers could be used for material identification in steel industry [15; 16], thus far, few scientific papers have been published on this topic. [PERSON] et al. [17] used a first generation specifically designed _NanoLIBS-Q h_LIBS instrument produced by B&W Tek (Newark, DE, USA) for steel analysis.