Recycling of Basic Oxygen Furnace (BOF) sludge in iron and steel works

Singh, Abhishek; Raju, M.; Jha, Usha

doi:10.1504/ijetm.2011.039255

Cited by 19 publications

(16 citation statements)

References 2 publications

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“…Recycling of the off-gas dust from the BOF to the BF has been successfully achieved using both cold-bonded briquettes [1] and sinter [8]. Again, one of the limiting factors in recycling the dust generated in the BOF process is the zinc content.…”

Section: Residuementioning

confidence: 99%

“…Thus, if other recycling routes are considered, the raw-material efficiency within the integrated steel plant can be improved. The BOF has been acknowledged as an alternative route for recycling off-gas dust [8,[17][18][19][20]. In one publication, recycling to the BOF by replacing the sinter coolant was recognized to be limited in tonnage [17].…”

Section: Residuementioning

confidence: 99%

“…Furthermore, cold-bonded briquettes were shown to be suitable for the recycling of all BOF sludge back to the BOF [20]. In addition, hot briquetting has been employed to recycle the BOF dust back to the BOF in industrial practice [8]. Nonetheless, adopting the BOF recycling route still requires considerations of zinc, especially when BOF dust is recycled to the BF.…”

Section: Residuementioning

confidence: 99%

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A Holistic and Experimentally-Based View on Recycling of Off-Gas Dust within the Integrated Steel Plant

Andersson

Gullberg²,

Kullerstedt³

et al. 2018

Metals

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Ore-based ironmaking generates a variety of residues, including slags and fines such as dust and sludges. Recycling of these residues within the integrated steel plant or in other applications is essential from a raw-material efficiency perspective. The main recycling route of off-gas dust is to the blast furnace (BF) via sinter, cold-bonded briquettes and tuyere injection. However, solely relying on the BF for recycling implicates that certain residues cannot be recycled in order to avoid build-up of unwanted elements, such as zinc. By introducing a holistic view on recycling where recycling via other process routes, such as the desulfurization (deS) station and the basic oxygen furnace (BOF), landfilling can be avoided. In the present study, process integration analyses were utilized to determine the most efficient recycling routes for off-gas dust that are currently not recycled within the integrated steel plants of Sweden. The feasibility of recycling was studied in experiments conducted in laboratory, pilot, and full-scale trials in the BF, deS station, and BOF. The process integration analyses suggested that recycling to the BF should be maximized before considering the deS station and BOF. The experiments indicated that the amount of residue that are not recycled could be minimized.

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Section: Residuementioning

confidence: 99%

Section: Residuementioning

confidence: 99%

Section: Residuementioning

confidence: 99%

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A Holistic and Experimentally-Based View on Recycling of Off-Gas Dust within the Integrated Steel Plant

Andersson

Gullberg²,

Kullerstedt³

et al. 2018

Metals

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“…There is a decreasing trend in landfilling of these materials, due to increasingly stringent environmental legislation and an increasing focus on waste minimization. The high moisture content of BOF sludge is a major obstacle in its recycling [7].…”

Section: Introductionmentioning

confidence: 99%

Selective Removal of Zinc from BOF Sludge by Leaching with Mixtures of Ammonia and Ammonium Carbonate

Rodriguez

Gijsemans

Bussé

et al. 2020

J. Sustain. Metall.

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The zinc content of basic oxygen furnace (BOF) sludges is too high for direct recycling into the blast furnace via the sinter plant, as excessive zinc concentrations are detrimental for the refractory lining of the blast furnace. However, by partial and selective removal of zinc from the BOF sludge, the residual sludge can be used as a secondary iron resource in the blast furnace. In this paper, BOF sludge was leached with aqueous ammonia, aqueous solutions of ammonium salts (chloride, carbonate, and sulfate), and aqueous mixtures of ammonia and ammonium salt. The mixtures of ammonia and ammonium salt could leach more zinc with respect to either the aqueous ammonia or the aqueous ammonium salt solution. The ammonia–ammonium carbonate (AAC) mixture was selected as the most suitable lixiviant due to the high zinc leaching efficiency in combination with a high selectivity towards iron; furthermore, this combination does not introduce unwanted chloride or sulfate impurities in the residue. The leaching process was optimized in terms of the liquid-to-solid ratio, total ammonia concentration, ammonium:ammonia molar ratio, temperature, and leaching time. The co-dissolved iron was precipitated as a hydroxide after oxidation of ferrous to ferric ions by an air stream, without co-precipitation of zinc, while the dissolved zinc could be easily recovered as zinc sulfide by precipitation with ammonium sulfide. The (almost) closed-loop process was successfully up-scaled from 10 mL to 1 L scale. Graphical Abstract

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“…No caso específico do setor siderúrgico, um dos resíduos que merece atenção é a lama de aciaria LD. Esse resíduo contém elevados teores de ferro total, da ordem de 50% a 60%, sendo coletado nos sistemas de limpeza de gases da aciaria durante a produção de aço via convertedores LD (1) e normalmente classificado nas frações fina e grossa, a depender da sua granulometria. Diversas aplicações têm sido sugeridas, dentre elas, a incorporação da lama na fabricação de materiais cerâmicos, o uso da lama como adsorvente de metais presentes em efluentes, a briquetagem da lama em substituição ao minério de ferro usado como refrigerante no processo de produção de aço, a reciclagem da lama fina na sinterização sob a forma de pelotas visando substituir o sinter feed na carga metálica.…”

Section: Introductionunclassified

Avaliação De Rota Híbrida Aplicada À Remoção Seletiva De Zinco Contido Na Lama De Aciaria Ld

Cantarino¹,

Cotta²,

Mansur

2012

TMM

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ResumoUma rota híbrida (pirometalúrgica + hidrometalúrgica) é avaliada na remoção seletiva de zinco presente na lama fina de aciaria LD. A rota consiste das seguintes etapas: i) decomposição térmica da franklinita (ZnO.Fe 2 O 3 ) contida na lama, na presença de NaOH, ii) lixiviação estagiada da lama fundida em solução de NaOH visando a remoção seletiva de zinco, e iii) lavagem da lama tratada com água para a remoção dos álcalis remanescentes do tratamento. As duas primeiras etapas são avaliadas em três condições operacionais distintas: branda, intermediária e severa. Observa-se que a etapa de decomposição da franklinita é fundamental para garantir elevadas remoções de zinco. Nas condições investigadas, obteve-se, como melhor resultado, uma remoção de 90% de zinco e perda insignificante de ferro, demonstrando que o método é altamente seletivo. A lavagem da lama tratada também se mostra eficaz, com remoção total de sódio e potássio. Assim, alcança-se um enriquecimento de aproximadamente 10 vezes na razão Fe/Zn presente na lama, passando originalmente de 11,6 para 128,8. Palavras-chave: Lama de aciaria; Zinco; Tratamento de resíduo; Meio ambiente. EVALUATION OF A HYBRID ROUTE FOR THE SELECTIVE REMOVAL OF ZINC FROM BASIC OXYGEN FURNACE SLUDGES AbstractA hybrid (pyro + hydrometallurgical) route is evaluated for the selective removal of zinc from the fine fraction of basic oxygen furnace sludges. The route consists of the following steps: i) thermal decomposition of the franklinite (ZnO. Fe 2 O 3 ) present in the sludge, in the presence of NaOH, ii) staged leaching of the sludge in NaOH solution in order to selectively remove zinc, and iii) washing of the sludge for the removal of reminiscent alkalis from the treatment. The first two steps are evaluated accordingly to three distinct operating conditions: soft, intermediate and severe. It is verified that the thermal decomposition of franklinite is a crucial step to assure the effective removal of zinc. A maximum of 90% of zinc was removed in the best tested condition with practically no loss of iron content, thus demonstrating that the route is very selective. The washing step is also efficient, with total removal of sodium and potassium. Finally, enrichment around 10 times on the Fe/Zn ratio is obtained, from originally 11.6 to 128.8.

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Recycling of Basic Oxygen Furnace (BOF) sludge in iron and steel works

Cited by 19 publications

References 2 publications

A Holistic and Experimentally-Based View on Recycling of Off-Gas Dust within the Integrated Steel Plant

A Holistic and Experimentally-Based View on Recycling of Off-Gas Dust within the Integrated Steel Plant

Selective Removal of Zinc from BOF Sludge by Leaching with Mixtures of Ammonia and Ammonium Carbonate

Avaliação De Rota Híbrida Aplicada À Remoção Seletiva De Zinco Contido Na Lama De Aciaria Ld

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