Recovery of chromium from chromium-bearing slags produced in the stainless-steel smelting: A review

Gu, Foquan; Zhang, Yuanbo; Su, Zijian; Tu, Yikang; Liu, Shuo; Jiang, Tao

doi:10.1016/j.jclepro.2021.126467

Cited by 47 publications

(26 citation statements)

References 86 publications

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“…Note the trivalent Cr (III) in the form of oxide is less toxic but it can be oxidized to harmful Cr (VI) at high oxygen concentrations or high MnO oxides. In general, the methods for recovering valuable metals/metal oxides from the BOS slags are categorized into physical separation, [121][122][123][124][125][126][127][128][129] reduction process, [130][131][132][133][134][135][136] and oxidation process. [137][138][139]…”

Section: Materials Recyclingmentioning

confidence: 99%

“…The highest reduction ratio of Fe and Cr achieved was 93.92% and 72.76%, respectively, under the condition of carbon equivalent 2, reduction temperature 1600 ºC, and binary basicity 1.2. [133][134][135] Adamczyk et al [136] compared the efficiency of the reducing agents of C, Al, FeSi, and SiC for reduction of chromium in the SSS slag. Al was the strongest reducing agent; however, it leads to reducing a lot of SiO 2 because of the strong reactivity of aluminum.…”

Section: Reduction Processmentioning

confidence: 99%

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Basic Oxygen Steelmaking Slag: Formation, Reaction, and Energy and Material Recovery

Spooner

et al. 2021

steel research int.

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The basic oxygen steelmaking (BOS) process produced over 70% of the global crude steel in 2018, [1] generating 100 to 150 kg of slag ("BOS slag") for every tonne of crude steel produced. BOS slag, a product of hot metal element (e.g., Si, Mn, Fe, P) oxidation and flux (e.g., lime, dolomite) dissolution, plays a critical role in the production of high-quality crude steel.All elements present in the hot metal charged in the BOS converter are thermodynamically very unstable with respect to their oxides when exposed to the oxygen jet at the BOS operating temperatures. Thus, carbon, silicon, manganese, phosphorus, and the iron itself all tend to oxidize very rapidly to form CO (or CO 2 ), SiO 2 , MnO, P 2 O 5 , and FeO (or Fe 2 O 3 ), respectively. In the BOS practice, large quantities of iron and silicon are initially oxidized to give a liquid, predominantly binary, FeO-SiO 2 slag, which floats on top of the metal pool. Usually lime (CaO) is rapidly added to "neutralize" this acid FeO-SiO 2 slag and produce a "basic" multicomponent FeO-SiO 2 -CaO-MnO-Al 2 O 3 -MgO-P 2 O 5 slag. This basic slag produces the correct partition of metalloids, particularly phosphorus, between the slag and metal and also protects the basic vessel lining (usually magnesite, MgO). Over the entire blowing period of the BOS process, this basic slag is emulsified with a large amount of gas bubbles and metal droplets, and the gas-slag-metal droplet reactions control the element transfer between the steel and slag (e.g., phosphorus removal and reversion) and subsequently the productivity and crude steel quality, which greatly attracts great interest from academics to understand the transient phenomena in the gas-BOS slag-metal droplet system. After completing its refining function in the BOS process, the hot BOS slag is poured into a slag pot. The BOS slag was considered a waste in old times but now as a secondary resource because it contains a large amount of thermal energy (temperature up to 1700 C), chemical energy (metallic and low-valence metallic oxides), and valuable materials (e.g., iron oxides).The behavior of BOS slag inside the BOS vessel, e.g., formation and reaction with gas and metal droplets, is still not clear and its recycling, including energy and material recovery, has always been challenging. This article introduces some BOS-slag-related research conducted by the present authors, in addition to a critical review of relevant research reported in the literature. It covers the topics of lime dissolution (slag formation), high-temperature-behavior interrogation through in situ observation, slag-metal droplet reaction mechanisms (spontaneous emulsification), and recovery of energy and materials from the molten BOS slag. This article aims to provide state-of-the-art understanding on relevant research topics and point out new research directions.

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Section: Materials Recyclingmentioning

confidence: 99%

Section: Reduction Processmentioning

confidence: 99%

Basic Oxygen Steelmaking Slag: Formation, Reaction, and Energy and Material Recovery

Spooner

et al. 2021

steel research int.

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“…Formation of chromium carbides (i.e. Cr 3 C 2 , Cr 7 C 3 and Cr 23 C 6 ) during the carbothermic reduction of Cr 2 O 3 has been detected in the experiments by Mori et al [17], who also concluded that the carbide formation may hinder the conversion of Cr 2 O 3 into metallic chromium [12,17]. To avoid this hindrance caused by the carbide formation, Wu et al [18] studied the effect of Fe 2 O 3 on the chromium reduction and found out that the presence of Fe 2 O 3 in the initial system results in the formation of Fe-C-alloys into which the reducing chromium is dissolved (rather than forming carbide precipitates) [12,18].…”

Section: Chromium Recoverymentioning

confidence: 91%

“…These volumetric changes cause solidified slag to disintegrate into very small particle size, which hinders the slag utilisation. In their recent review on the recovery of chromium from chromium-containing slags Gu et al [12] pointed out that although the recovery of chromium from molten slags is relatively high in comparison to e.g. physical separation techniques and bioleaching, in which chromium is recovered from solidified slags, the smelting reduction also faces disadvantages such as high energy consumption and high recycling costs [12].…”

Section: Introductionmentioning

confidence: 99%

“…In their recent review on the recovery of chromium from chromium-containing slags Gu et al [12] pointed out that although the recovery of chromium from molten slags is relatively high in comparison to e.g. physical separation techniques and bioleaching, in which chromium is recovered from solidified slags, the smelting reduction also faces disadvantages such as high energy consumption and high recycling costs [12]. In order to decrease the high energy consumption, it would be beneficial to recover chromium from the molten state before it is solidified at all.…”

Section: Introductionmentioning

confidence: 99%

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A computational study on the mixing and reduction of slags from ferrochrome and stainless steel production

Heikkinen

Heikkilä

Vallo

et al. 2021

Calphad

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Redox‐Functionalized Semiconductor Interfaces for Photoelectrochemical Separations

Cho

Chen

Elbert

et al. 2023

Small

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Redox‐mediated electrosorption is a promising platform for selective electrochemical (EC) separations, due to its molecular selectivity, high uptake, and tunability for target ions. However, the electrical energy required is mainly generated by non‐renewable energy sources, which limits its sustainability and overall impact to decarbonization. Here, a redox‐mediated photoelectrochemical (PEC) separation process using polyvinyl ferrocene functionalized TiO2 nanorod electrodes is proposed, which integrates direct solar energy as a driver for the selective electrosorption. The photoelectrochemically‐driven oxidation and reduction with both homogeneous and heterogeneous ferrocene‐systems is investigated to establish the underlying mechanism. The PEC system can separate heavy metal oxyanions at lower voltages or even without electrical energy. At 0.3 V versus SCE, a 124 mg g−1 uptake for Mo is achieved, which is comparable to the performance of EC cells at 0.75 V versus SCE. Thus, PEC systems not only can generate energy for spontaneous redox‐separations, but also can reduce electrical energy consumption by 51.4% compared to EC cells for separation processes when coupled with an external electrical energy.

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Recovery of chromium from chromium-bearing slags produced in the stainless-steel smelting: A review

Cited by 47 publications

References 86 publications

Basic Oxygen Steelmaking Slag: Formation, Reaction, and Energy and Material Recovery

Basic Oxygen Steelmaking Slag: Formation, Reaction, and Energy and Material Recovery

A computational study on the mixing and reduction of slags from ferrochrome and stainless steel production

Redox‐Functionalized Semiconductor Interfaces for Photoelectrochemical Separations

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