Effect of South Africa Reductants on Ferrochrome Production

Pan, Xiaowei

doi:10.3182/20130825-4-us-2038.00116

Cited by 5 publications

(4 citation statements)

References 1 publication

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“…More so, to separate the Cr-containing alloy from the slag phase, high operating temperatures are required [34]. Electrical energy is the main energy supply required for smelting [35], and various C sources are used as the reductant, e.g., coke, coal, and charcoal [14,33]. In general, reductants with low ash, phosphorous, and sulfur contents are preferred for FeCr production [22,36].…”

Section: Chromite Smelting Principlesmentioning

confidence: 99%

“…Beukes and Guest (2001) reported elevated Cr(VI) levels in samples gathered from a dry-milling circuit at a FeCr producer. As appose to dry milling, wet milling does not generate Cr(VI) [35]. More so, wet milling would be the obvious choice considering that the preceding beneficiation steps (spiral concentrators and hydrocyclones) are wet processes.…”

Section: Chromite Ore Beneficiationmentioning

confidence: 99%

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An Overview of Currently Applied Ferrochrome Production Processes and Their Waste Management Practices

du Preez,

van Kaam,

Ringdalen

et al. 2023

Minerals

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Ferrochrome (FeCr) is the main source of virgin chromium (Cr) units used in modern-day chromium (Cr) containing alloys. The vast majority of produced Cr is used during the production of stainless steel, which owes its corrosion resistance mainly to the presence of Cr. In turn, stainless steel is mainly produced from Cr-containing scrap metal and FeCr, which is a relatively crude alloy between iron (Fe) and Cr. The production of FeCr is an energy and material-intensive process, and a relatively wide variety of by-products, typically classified as waste materials by the FeCr industry, are created during FeCr production. The type and extent of waste generation are dictated by the smelting route used and the management practices thereof employed by a specific smelter. In some cases, waste management of hazardous and non-hazardous materials may be classified as insufficient. Hazardous materials, such as hexavalent Cr, i.e., Cr(VI), -containing wastes, are only partially mitigated. Additionally, energy-containing wastes, such as carbon monoxide (CO)-rich off-gas, are typically discarded, and energy-invested materials, such as fine oxidative sintered chromite, are either stockpiled or sold as ordinary chromite. In cases where low-value containing wastes are generated, such as rejects from ore beneficiation processes, consistent and efficient processes are either difficult to employ or the return on investment of such processes is not economically viable. More so, the development of less carbon (C)-intensive (e.g., partial replacement of C reductants) and low-temperature pellet curing processes are currently not considered by the South African FeCr smelting industry. The reasoning for this is mainly due to increased operation costs (if improved waste management were to be implemented/higher cost reductants were used) and a lack of research initiatives. These reasons result in the stagnation of technologies. From an environmental point of view, smelting industries are pressured to reduce C emissions. An attractive approach for removing oxygen from the target metal oxides, and the mitigation of gaseous C, is by using hydrogen as a reductant. By doing so, water vapor is the only by-product. It is however expected that stable metal oxides, such as the Cr-oxide present in chromite, will be significantly more resistive to gaseous hydrogen-based reduction when compared to Fe-oxides. In this review, the various processes currently used by the South African FeCr industry are summarized in detail, and the waste materials per process step are identified. The limitations of current waste management regimes and possible alternative routes are discussed where applicable. Various management regimes are identified that could be improved, i.e., by utilizing the energy associated with CO-rich off-gas combustion, employing a low-temperature alternative chromite pelletization process, and considering the potential of hydrogen as a chromite reductant. These identified regimes are discussed in further detail, and alterative processes/approaches to waste management are proposed.

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Section: Chromite Smelting Principlesmentioning

confidence: 99%

Section: Chromite Ore Beneficiationmentioning

confidence: 99%

An Overview of Currently Applied Ferrochrome Production Processes and Their Waste Management Practices

du Preez,

van Kaam,

Ringdalen

et al. 2023

Minerals

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“…The country's production accounted for around 34% of global ferrochrome production in 2013. Most South African producers have smelting facilities and chromite mines within the BIC [17].…”

Section: The Ferrochrome Industrymentioning

confidence: 99%

“…Open furnaces had an intensity of 4.23 ± 0.32 kWh/kg FeCr whilst closed furnaces with preheated ore had an intensity of 3.32 ± 0.24 kWh/kg FeCr and closed furnaces without preheated ore had an intensity of 4.38 ± 0.48 kWh/kg FeCr. The closed furnace enables the use of hot furnace gas to preheat ore. Pan [17] estimated a range of 3.3-3.8 kWh/kg FeCr for varying South African ore types. The reported electrical intensities by the companies are mostly within the ranges stated in these two studies, though since 2015, Glencore-Merafe has consistently performed better than these benchmarks.…”

Section: Energy Intensity Trendsmentioning

confidence: 99%

Resource Intensity Trends in the South African Ferrochrome Industry from 2007 to 2020

Dlamini

Blottnitz

2022

Minerals

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Processing resource requirements in mineral extractive industries tend to increase over time as ore grades decrease, which consequently increases the environmental footprint of operations and products. This phenomenon may be alleviated by cleaner production interventions. South Africa is the largest global supplier of chromium. This study investigates the impact of cleaner production process improvements on selected resource intensities of the South African ferrochrome industry. Sustainability data, available since the start of regular sustainability reporting in 2007, were used to compile resource intensity trends. This was followed by a review of industry capital projects relating to resource-use optimisation, interrogated in interviews with industry experts, to ascertain their effect on resource intensities. The emergence of a symbiotic relationship with the platinum-group metals industry was identified as a major development, with chromite ore intensity decreasing from 2.54 to 1.98 kg per kg ferrochrome. Electrical energy intensity was observed to decrease from 3.47 to 2.86 kWh per ton ferrochrome, mainly as a result of cleaner smelting technology, though cogeneration fired by furnace off-gases also contributed significantly. The introduction of cleaner production interventions in the South African ferrochrome industry was thus documented to have resulted in decreased resource use intensities.

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Effect of Stoichiometric Reductants on the Process of Ferrochrome Production at 1200–1550°C

2017

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Effect of South Africa Reductants on Ferrochrome Production

Cited by 5 publications

References 1 publication

An Overview of Currently Applied Ferrochrome Production Processes and Their Waste Management Practices

An Overview of Currently Applied Ferrochrome Production Processes and Their Waste Management Practices

Resource Intensity Trends in the South African Ferrochrome Industry from 2007 to 2020

Effect of Stoichiometric Reductants on the Process of Ferrochrome Production at 1200–1550°C

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