Effect of Lead and Zinc Impurities in Ironmaking and the Corresponding Removal Methods: A Review

Mustafa, Sayaf; Luo, Liqun; Zheng, Botao; Wei, Chenxi; Christophe, Niyonzima

doi:10.3390/met11030407

Cited by 11 publications

(5 citation statements)

References 70 publications

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“…These materials can use coke, pulverized coal, and lime or limestone as reducing agents, heat sources, and fluxing agents, respectively. BOF ironmaking mainly aims to produce a hot metal with consistent quality [6].…”

Section: Geological Characterization Of Xinjiang Iron Orementioning

confidence: 99%

“…Impurities of Pb and Zn are present in iron, and form complex ores, which are difficult to remove at high temperatures. These impurities lead to a decrease in iron productivity [6], which seriously affects the lifetime of blast furnaces and the benefits of ironmaking [12]. These impurities are easy to reduce or oxidize, and can expand and form lead-containing precipitations and zinc-containing dust, seriously affecting the production of the blast furnace.…”

Section: Impurities In Iron Orementioning

confidence: 99%

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Mineralogical and Chemical Changes after Reduction Roasting of Xinjiang Iron Ore, China

Mustafa

Luo

Zheng

et al. 2022

Metals

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The mineralogical and chemical changes in Chinese Xinjiang iron ore containing impurities, lead, and zinc as a result of reduction roasting were studied via chemical analysis, optical microscopy, X-ray fluorescence (XRF), electron probe microanalysis (EPMA), and energy-dispersive spectroscopy (EDS). Analysis showed that hematite was the main iron-bearing mineral, with small amounts of magnetite and iron silicate; lead impurities were mainly lead oxide and lead–iron alum, while zinc oxide was the main zinc impurity. X-ray fluorescence analysis for raw samples indicated the presence of quartz, hematite, magnetite, chlorite, calcite, and dolomite. The results of the analysis of roasted samples showed an increase in hematite at temperatures of 750 °C and 950 °C, while the elemental iron increased at a temperature of 1200 °C, along with the conversion of galena to lead oxide and sphalerite to zinc oxide, with a stable quartz ratio. The chemical analysis of the raw sample showed that the TFe grade of the sample was 47.04%, while the contents of harmful Pb and Zn impurities were 0.39% and 0.30%, respectively, both of which exceed the index (less than 0.10%) required by the iron industry for raw materials. The content of harmful sulfur impurities was also high, at 1.19%, which needs to be eliminated or reduced. The results of EPMA and EDS analysis of pre-roasting raw samples showed that chemical compositions vary in different locations in the hematite, magnetite, sphalerite, and galena micro-zones. It has also been observed that quartz is mostly diffused with magnetite and hematite, and sulfur appears in small quantities in most regions. The analysis after roasting showed that the percentages of lead, zinc, and sulfur impurities decreased by a large rate. It is clear that the roasting process plays a major role in removing impurities such as sulfur, which appears in a small percentage after the roasting process, and also helps in oxidizing the impurities of lead and zinc, which helps in removing them.

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Section: Geological Characterization Of Xinjiang Iron Orementioning

confidence: 99%

Section: Impurities In Iron Orementioning

confidence: 99%

Mineralogical and Chemical Changes after Reduction Roasting of Xinjiang Iron Ore, China

Mustafa

Luo

Zheng

et al. 2022

Metals

Self Cite

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“…The apparent association of Pb and Zn in several samples, with diverse other mineralogical associations, would require further investigation to interpret confidently. Possible sources of material with association of Pb and Zn include historic Zn-Pb galvanising material [30] (no longer produced locally), pyrotechnic compositions for fireworks (which may also contain additionally Cu) [25, [31][32][33] and potentially stack emissions from integrated steelmaking which are known to contain concentrations of both elements [34,35]. Beyond the specific examples in sample 21, we do not speculate further on which, if any, of these sources contribute to the Zn associated Pb-rich pixels in the current samples.…”

Section: Character and Potential Provenance Of The Detected Pb-rich Phase Occurrencesmentioning

confidence: 99%

Screening Coarse Airborne Dust for Lead-Rich Phase Occurrence during Characterisation of Particle Mineralogy, Chemistry and Provenance: Application to Deposits in the Vicinity of an Integrated Steelworks

et al. 2021

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A method has been developed to screen large numbers (~103–104 per sample) of coarse airborne dust particles for the occurrence of Pb-rich phases, together with quantification of the particles’ mineralogy, chemistry, and inferred provenance. Using SEM-EDS spectral imaging (SI) at 15 kV, and processing with the custom software PARC, screening of individual SI pixels is performed for Pb at the concentration level of ~10% at a length-scale of ~1 µm. The issue of overlapping Pb-Mα and S-Kα signal is resolved by exploiting peak shape criteria. The general efficacy of the method is demonstrated on a set of NIST particulate dust standard reference materials (SRMs 1649b, 2580, 2584 and 2587) with variable total Pb concentrations, and applied to a set of 31 dust samples taken in the municipalities surrounding the integrated steelworks of Tata Steel in IJmuiden, the Netherlands. The total abundances of Pb-rich pixels in the samples range from none to 0.094 area % of the (total) particle surfaces. Overall, out of ca. 92k screened particles, Pb was found in six discrete Pb-phase dominated particles and, more commonly, as superficial sub-particles (sub-micron to 10 µm) adhering to coarser particles of diverse and Pb-unrelated provenance. No relationship is apparent between the samples’ Pb-rich pixel abundance and their overall composition in terms of particle provenance.

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“…The Pb concentration continues to decrease with smelting progress, so Pb slag is divided into low-lead slag and high-lead slag [1][2][3][4]. Pb and Zn are easily converted into volatile substances such as PbO(g), Zn(g) under reasonable conditions [4][5][6][7]. These substances volatilise at high temperatures and form heavy metal dust [8,9].…”

Section: Introductionmentioning

confidence: 99%

Volatilisation Behaviour and Mechanism of Lead-Containing Slag during Physical Property Tests

Tang,

Zhao

2024

Materials

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According to physical property tests of lead-containing slag, the volatilisation behaviour of lead slag will have adverse impacts on test accuracy and further affect the control of chemical reactions, solidification and removal of inclusions during smelting. To analyse the volatilisation characteristics of lead slag, in this paper, four kinds of lead slags from lead direct reduction smelting with different PbO and ZnO content are taken. thermogravimetry, ISP-TOF were used. Additionally, the changes in volatiles and slag composition and phases were analysed with XRD and ICPS, and the volatilisation reaction mechanism was discussed. The results indicated that the volatilisation of lead slag can lead to a big weight loss of about to the slag with higher PbO content. The weight loss increases with the PbO content in slag increases. The volatile corresponding to the weight loss above 900 °C is mainly PbO and less ZnO. The higher the temperature is, the stronger the volatilisation is. With the increase in temperature and keeping time, most of the PbO can be evaporated and leaves little PbO in the residual slag. This will has great effect to physico-chemical property measurement of the slag with higher PbO content, especially to the property measurement that be kept at high temperature for a long time. Because the volatiles is trend to condense with the temperature decrease, mass spectrometer is limited by the condensation of volatiles, i.e., PbO, ZnO and so on, in the connection pipeline. The device should be modified for this use.

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Effect of Lead and Zinc Impurities in Ironmaking and the Corresponding Removal Methods: A Review

Cited by 11 publications

References 70 publications

Mineralogical and Chemical Changes after Reduction Roasting of Xinjiang Iron Ore, China

Mineralogical and Chemical Changes after Reduction Roasting of Xinjiang Iron Ore, China

Screening Coarse Airborne Dust for Lead-Rich Phase Occurrence during Characterisation of Particle Mineralogy, Chemistry and Provenance: Application to Deposits in the Vicinity of an Integrated Steelworks

Volatilisation Behaviour and Mechanism of Lead-Containing Slag during Physical Property Tests

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