Reuse of EAF Slag as Reinforcing Filler for Polypropylene Matrix Composites

Abstract

Electric-arc furnace (EAF) slag, the by-product of steel fabricated at the EAF, is in most cases still sent to dumps, with serious environmental consequences. This work shows an innovative, economically convenient application for EAF slag: its use as reinforcing filler for polypropylene. Composites based on polypropylene containing 10–40 wt.% of EAF slag particles were prepared by melt compounding followed by injection molding. A physical–chemical analysis of the EAF slag was performed to determine microstructural features and main component phases. Leaching tests demonstrated that, although EAF slag can release small amounts of toxic elements, such as heavy metals, incorporating such material into the polymeric matrix immobilizes the heavy metals inside that matrix. The mechanical characterization of the polymer-based composites was performed. Incorporating EAF slag particles raises the Young’s modulus and the tensile strength at yield, whereas elongation at break and the impact strength of the polymer-based composite are significantly reduced only when large amounts of filler are added, i.e., 30% or more

A Circular Economy Virtuous Example—Use of a Stabilized Waste Material Instead of Calcite to Produce Sustainable Composites

“…The influence of stabilized FA as filler in epoxy resin matrix on the elongation at break is similar to that of calcium carbonate. As expected, increasing the filler amount in the epoxy matrix the elongation and the straight at break decrease, while the flexural modulus increases [45][46][47]. In general, the same content [% wt] of ash and calcium carbonate affects the composite flexural behavior similarly.…”

Grain Size Effect in Elution Test of Electric Arc Furnace Slag

“…Indeed, it was shown that aggregates containing EAF slags have excellent physical and chemical characteristics, and thus can be used in cement-treated materials [13]. EAF slags are also used in wastewater treatment [14][15][16], CO 2 sequestration [17], agriculture fertilizer or remedy for soil acidity [18], and reinforcing filler for composite materials [19,20]. The recycling of steel slag may be restricted because of the presence of potentially toxic elements-like Cr, V, Ba and Mo [21]-and leaching tests are mandatory to verify the release of toxic elements in the water [22].…”

Innovative Reuse of Electric Arc Furnace Slag as Filler for Different Polymer Matrixes

“…The slag employed in this research as filler has been produced by an electric arc furnace process, so that it is a "black" slag. In particular after slagging it has been treated by a specific system named Slag-Rec [17,31].…”

“…EAF slag used as filler for PP matrix in [31] was produced by the same Slag-Rec system, but it derived from a different casting with respect to that used as filler for NBR, ELT, and epoxy matrixes.…”

“…The reuse of EAF slag as filler for a polymer matrix was assessed for the first time in 2015 by Cornacchia et al [31]. Nevertheless, it is interesting to evaluate the influence of EAF slag also in materials which belong to a very different class of polymers characterized by different applications, production process and behavior.…”