Characterization and Reduction Behavior of Mill Scale

Abstract

This paper presents an initial part of a project devoted to the recycling of mill scale in the form of selfreducing briquettes. First chemical and morphological characteristics of mill scale were investigated and next its gaseous reduction behavior was studied by thermogravimetry. The chemical characterization showed that wustite is the major constituent of this waste matter, with small amounts of magnetite, hematite and metallic iron. The microscopic examination of the scale revealed its complex and layered microstructure with three distinct zones. The outer layer is relatively thin and porous. It is mainly composed of hematite and magnetite. The intermediate layer is made of the dense, columnar grains of wustite. The inner layer is a very porous wustite. The gaseous reduction by carbon monoxide has a topochemical character regardless of initial morphology of scale and, depending on temperature and reducing gas composition it produces a porous iron or the iron whiskers. The unreacted shrinking core model with one interface fits quite well the kinetic data and the activation energy of reduction is about 80 kJ/mol.

Characterization of steel billet scales generated during the continuous casting process in SIDERPERU steel plant

“…Its related parameters are listed in Table 2. These results obtained by XRD are similar to the reported by Bagatini et al in their studies on mill scale and Farahat et al in their work in the reduction of mill scale [11,12]. Note that the mineral phases are in well agree to compositional elements found by EDX and XRF.…”

Characterization of steel billet scales generated during the continuous casting process in SIDERPERU steel plant

“…Its related parameters are listed in Table 2. These results obtained by XRD are similar to the reported by Bagatini et al in their studies on mill scale and Farahat et al in their work in the reduction of mill scale [11,12]. Note that the mineral phases are in well agree to compositional elements found by EDX and XRF.…”

Thermal Analysis Study on the Carbothermic Reduction of Chromite Ore with the Addition of Mill Scale

“…The as‐reduced iron has very high active surfaces and carbon will dissolve in the iron. The dissolution of carbon in the iron is validated by SEM/EDS analysis, and this is also consistent to Bagatini et al's observation that carbon was picked up by iron during the reduction of mill scale As temperature increases, more and more carbon diffuses into the as‐reduced iron, and iron starts to soften and coalesce to form a network structure, in which chromite ore are surrounded.…”

Direct Reduction Recycling of Mill Scale Through Iron Powder Synthesis

“…Similar observation of presence of spongy iron at higher temperatures and whisker form of iron at low temperatures is reported by Bagatini and co-workers. 2) SEM and XRD results shown in Fig. 5 also supports the dependency of sintering on metallic iron formation.…”

Characterization of steel billet scales generated during the continuous casting process in SIDERPERU steel plant

“…Its related parameters are listed in Table 2. These results obtained by XRD are similar to the reported by Bagatini et al in their studies on mill scale and Farahat et al in their work in the reduction of mill scale [11,12]. Note that the mineral phases are in well agree to compositional elements found by EDX and XRF.…”

Thermal Analysis Study on the Carbothermic Reduction of Chromite Ore with the Addition of Mill Scale

“…The as‐reduced iron has very high active surfaces and carbon will dissolve in the iron. The dissolution of carbon in the iron is validated by SEM/EDS analysis, and this is also consistent to Bagatini et al's observation that carbon was picked up by iron during the reduction of mill scale As temperature increases, more and more carbon diffuses into the as‐reduced iron, and iron starts to soften and coalesce to form a network structure, in which chromite ore are surrounded.…”

Direct Reduction Recycling of Mill Scale Through Iron Powder Synthesis

“…Similar observation of presence of spongy iron at higher temperatures and whisker form of iron at low temperatures is reported by Bagatini and co-workers. 2) SEM and XRD results shown in Fig. 5 also supports the dependency of sintering on metallic iron formation.…”

Characterization of steel billet scales generated during the continuous casting process in SIDERPERU steel plant

“…Its related parameters are listed in Table 2. These results obtained by XRD are similar to the reported by Bagatini et al in their studies on mill scale and Farahat et al in their work in the reduction of mill scale [11,12]. Note that the mineral phases are in well agree to compositional elements found by EDX and XRF.…”

Thermal Analysis Study on the Carbothermic Reduction of Chromite Ore with the Addition of Mill Scale

“…The as‐reduced iron has very high active surfaces and carbon will dissolve in the iron. The dissolution of carbon in the iron is validated by SEM/EDS analysis, and this is also consistent to Bagatini et al's observation that carbon was picked up by iron during the reduction of mill scale As temperature increases, more and more carbon diffuses into the as‐reduced iron, and iron starts to soften and coalesce to form a network structure, in which chromite ore are surrounded.…”

Direct Reduction Recycling of Mill Scale Through Iron Powder Synthesis

“…Similar observation of presence of spongy iron at higher temperatures and whisker form of iron at low temperatures is reported by Bagatini and co-workers. 2) SEM and XRD results shown in Fig. 5 also supports the dependency of sintering on metallic iron formation.…”