Thermo-environmental evaluation of a modified Waelz process for hazardous waste treatment

Neto, Ascendino Pereira de Araújo; Sales, Fabricia Araújo; Ramos, Wagner Brandão; Brito, Romildo Pereira

doi:10.1016/j.psep.2020.11.021

Cited by 6 publications

(2 citation statements)

References 14 publications

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“…Zinc resources are nonrenewable and are becoming increasingly scarce with continuous exploitation and use. − Consequently, low-grade zinc ores and zinc-containing wastes are receiving increased attention, with researchers exploring ways to extract valuable metals from them. , Iron slag, a solid waste produced during the purification and impurity removal stage of the wet zinc smelting process, is of particular interest. Wet zinc smelting, which accounts for over 85% of the world’s zinc production, has become the dominant method for zinc smelting. − Iron slag, with its high iron and zinc content, has significant potential for comprehensive recovery and utilization. , However, as a viscous material, iron slag retains a high moisture content of over 40% even after treatment with a plate and frame filter press. − This high moisture content can cause slag dampness and stickiness, leading to clumping that severely affects the feeding systems of rotary kilns and smelting furnaces. , This can result in furnace feed disruptions, large fluctuations in furnace conditions, a decrease in zinc oxide quality, and increased labor intensity for workers. , Moreover, the high moisture content of iron slag makes subsequent dehydration processes difficult and energy-intensive. , …”

Section: Introductionmentioning

confidence: 99%

“…Zinc resources are nonrenewable and are becoming increasingly scarce with continuous exploitation and use. 1 − 3 Consequently, low-grade zinc ores and zinc-containing wastes are receiving increased attention, with researchers exploring ways to extract valuable metals from them. 4 , 5 Iron slag, a solid waste produced during the purification and impurity removal stage of the wet zinc smelting process, is of particular interest.…”

Section: Introductionmentioning

confidence: 99%

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Study on the Drying Kinetics of Zinc Smelting Iron Slag Assisted by Ultrasonic Waves

Cheng,

Dai,

Zhang

et al. 2024

ACS Omega

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This study investigates the impact of ultrasonic treatment on the drying kinetics of zinc smelting iron slag. Through the Arrhenius equation, it was found that the reaction order of zinc smelting iron slag remains constant at 1/2 before and after ultrasonic treatment, indicating a proportional relationship between the reaction rate and the square root of the reactant concentration. Despite the increased drying rate of the iron slag due to ultrasonic pretreatment, the reaction order remains at 1/2. Additionally, it was observed that the drying kinetics of untreated iron slag aligns with the Wang and Singh model, while the drying kinetics of ultrasonically pretreated iron slag fits the Page model. The Page model facilitates the prediction of drying rate and drying time for ultrasonically pretreated iron slag, enabling the optimization of the drying process, enhancing efficiency, and comparing drying performance under different conditions. Using ultrasonic pretreatment, the subsequent drying process of iron slag can significantly shorten the time and save energy. These findings provide essential theoretical foundations for optimizing the drying process of zinc smelting iron slag.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Study on the Drying Kinetics of Zinc Smelting Iron Slag Assisted by Ultrasonic Waves

Cheng,

Dai,

Zhang

et al. 2024

ACS Omega

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Comprehensive investigation of two environmentally-friendly imidazolium nitrate ionic liquids: from calorimetry to thermal risk evaluation

Liu

Chen³

2022

J Therm Anal Calorim

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Alternative Method for Treating Electric Arc Furnace Dust: Simulation and Life Cycle Assessment

Rinne

Halli

Aromaa

et al. 2022

J. Sustain. Metall.

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The technical and environmental aspects of treating electric arc furnace dust (EAFD) using a novel process including alkaline roasting and organic acid leaching were evaluated and compared to the globally applied conventional Waelz process. The global warming potentials of the roasting–organic acid leaching process (with co-product credits) and the Waelz processes were 7.48 and 4.71 kg CO2-eq with 33% Zn dust as the feed material. However, with decreasing Zn content, the novel process become environmentally more competitive, and with 12% Zn, the corresponding GWP values were 6.31 and 9.26 kg CO2-eq. Co-product recovery decreased the net environmental impacts from the processing of the dust, which gave some benefits to the novel process. The Waelz process was observed to be energy intensive; however, the high consumption of leaching and roasting chemicals was the issue in the novel process. The excess caustic soda in the roasting step was observed to be a significant factor in the overconsumption of the organic acid in the leaching stage, and therefore, optimization of the roasting step is crucial. Other ways to decrease leaching chemical consumption include investigating the possibility to reuse the raffinate in leaching, or scrubbing the leach calcine from acid-consuming alkali. Evaluating the impacts of novel processes early enables iterative and agile process development and the directing the focus on the problem areas. Graphical Abstract

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Thermo-environmental evaluation of a modified Waelz process for hazardous waste treatment

Cited by 6 publications

References 14 publications

Study on the Drying Kinetics of Zinc Smelting Iron Slag Assisted by Ultrasonic Waves

Study on the Drying Kinetics of Zinc Smelting Iron Slag Assisted by Ultrasonic Waves

Comprehensive investigation of two environmentally-friendly imidazolium nitrate ionic liquids: from calorimetry to thermal risk evaluation

Alternative Method for Treating Electric Arc Furnace Dust: Simulation and Life Cycle Assessment

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