Direct Reduction Experiment on Iron-Bearing Waste Slag

Xiang-li, Cheng; Zhao, Kai; Qi, Yuan-hong; Shi, Xuefeng; Zhen, Chang-liang

doi:10.1016/s1006-706x(13)60064-3

Cited by 19 publications

(13 citation statements)

References 5 publications

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“…Reactive FeO can react with SiO 2 to form fayalite at high temperature (Equation (6)), which hinders the reduction of FeO to metallic Fe. While the CaO is added, the fayalite may readily react with fixed carbon and/or CaO to form Fe and wollastonite (Equations (7) and (8)) [41,42], which generates more metallic iron. The results revealed that higher alkalinity (w(CaO)/w(SiO 2 )) of slag phase could promote more gold allocated in iron phase rather than in slag phase.…”

Section: Effect Of Cao Dosagementioning

confidence: 99%

Recovery of Gold and Iron from Cyanide Tailings with a Combined Direct Reduction Roasting and Leaching Process

Feng

et al. 2018

Metals

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Cyanide tailings are the hazardous waste discharged after gold cyanidation leaching. The recovery of gold and iron from cyanide tailings was investigated with a combined direct reduction roasting and leaching process. The effects of reduction temperature, coal dosage and CaO dosage on gold enrichment into Au-Fe alloy (FexAu1−x) were studied in direct reduction roasting. Gold containing iron powders, i.e., Au-Fe alloy, had the gold grade of 8.23 g/t with a recovery of 97.46%. After separating gold and iron in iron powders with sulfuric acid leaching, ferrous sulfate in the leachate was crystallized to prepare FeSO4·7H2O with a yield of 222.42% to cyanide tailings. Gold enriched in acid-leaching residue with gold grade of 216.58 g/t was extracted into pregnant solution. The total gold recovery of the whole process reached as high as 94.23%. The tailings generated in the magnetic separation of roasted products, with a yield of 51.33% to cyanide tailings, had no toxic cyanide any more. The gold enrichment behaviors indicated that higher reduction temperature and larger dosage of coal and CaO could promote the allocation of more gold in iron phase rather than in slag phase. The mechanism for enriching gold from cyanide tailings into iron phase was proposed. This work provided a novel route to simultaneously recover gold and iron from cyanide tailings.

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Section: Effect Of Cao Dosagementioning

confidence: 99%

Recovery of Gold and Iron from Cyanide Tailings with a Combined Direct Reduction Roasting and Leaching Process

Feng

et al. 2018

Metals

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“…Hence, the liquid slag conclusion is strengthened. Additionally, previous investigations have shown that for a slag containing Fe, Si, and O as the main elements, whereby they account for 90% of the slag, the main phase is fayalite and has a melting point of 1200 • C [25]. The slags in Trials 1 and 2 also contain the main ion elements Fe, Si, and O, with a combined amount of 90.6 mass-%.…”

Section: Trialsmentioning

confidence: 95%

Experimental Determinations of Mixing Times in the IronArc Pilot Plant Process

Bölke

Ersson

Andersson

et al. 2019

Metals

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IronArc is a newly developed technology and an emerging future process for pig iron production. The long-term goal with this technology is to reduce the CO2 emissions and energy consumption compared to existing technologies. The production rate of this process is dependent on the stirring, which was investigated in the pilot plant process by measuring the mixing time in the slag bath. Moreover, slag investigations were done both based on light optical microscope studies as well as by Thermo-Calc calculations in order to determine the phases of the slag during operation. This was done because the viscosity (which is another important parameter) is dependent on the liquid and solid fractions of the slag. The overall results show that it was possible to determine the mixing time by means of the addition of a tracer (MnO2 powder) to the slag. The mixing time for the trials showed that the slag was homogenized after seconds. For two of the trials, homogenization had already been reached in the second sample after tracer addition, which means ≤8 s. The phase analysis from the slag indicated that the slag is in a liquid state during the operation of the process.

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“…( 4), with an equilibrium temperature of approximately 910 °C: ΔG = 12 477 -10.55T (4) Thermodynamic calculation results of fayalite reduction by CO indicates that addition of an alkaline oxide like CaO can improve the fayalite reduction by chemically combining with SiO2 to form wollastonite (CaO•SiO2) as shown in eqn. ( 5) (Xian-Lin et al, 2015;Cheng et al, 2013) (5) ΔG = -79 956 + 13.06T…”

Section: Fig 18 Metallic Iron Nuggets Formed From Slag Sample After Firingmentioning

confidence: 99%

“…Using the chars produced at 1550 °C as reductants they were able to achieve about 90% iron oxide reduction (Dankwah et al, 2016 oxide because the slag typically exists as a spinel fayalite, which is difficult to reduce carbothermally. Cheng et al (2013) investigated the direct reduction experiment on iron-bearing waste slag. They observed that addition of Al2O3 to the slag can improve the metallisation rate from between 74-77% to over 88% at temperatures around 1250 °C.…”

Section: Introductionmentioning

confidence: 99%

Production of Iron Nuggets from the Akpafu-Todzi Iron Ore and Artisanal Ferrous Slag using Post Consumer Thermosets (Waste Electrical Sockets) as Reductants

Baah¹,

Dankwah²,

Dankwah³

et al. 2019

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Post-consumer thermosets are difficult to recycle because, unlike thermoplastics, they cannot be remoulded to create other items as a result of the extensive cross-linkages in their structure. The increased production of thermoset blends and composites in recent years has greatly increased the amount of waste materials. However, higher levels of carbon and hydrogen present in thermosets make them a potential reductant in the iron extractive industries. In this research work, postconsumer thermoset was transformed into carbon resource through a charring process. The resulting carbonaceous material from the thermoset was used as reductant in the production of metallic iron from the Akpafu-Todzi iron ore and artisanal slag using the microwave technology through the composite pellet approach at varying firing times. Analyses by XRF, XRD and SEM/EDS showed that the Akpafu Todzi iron ore is comprised of the iron oxides hematite (Fe2O3) and wustite (Fe0.942O), while the artisanal slag was predominantly fayalite (Fe2SiO4). Complete reduction of the ore was attained after 120 min reduction but the maximum extent of reduction was 78.84% for the slag, demonstrating the potential of postconsumer thermosets to function effectively as a reductant in the iron extractive industry. Keywords: Reduction; Akpafu-Todzi Iron Ore; Post Consumer Thermosets; Waste Electrical Sockets

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Direct Reduction Experiment on Iron-Bearing Waste Slag

Cited by 19 publications

References 5 publications

Recovery of Gold and Iron from Cyanide Tailings with a Combined Direct Reduction Roasting and Leaching Process

Recovery of Gold and Iron from Cyanide Tailings with a Combined Direct Reduction Roasting and Leaching Process

Experimental Determinations of Mixing Times in the IronArc Pilot Plant Process

Production of Iron Nuggets from the Akpafu-Todzi Iron Ore and Artisanal Ferrous Slag using Post Consumer Thermosets (Waste Electrical Sockets) as Reductants

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