Effects of CaO on Reduction of Copper Slag by Biomass Based on Ion and Molecule Coexistence Theory and Thermogravimetric Experiments

Zuo, Zongliang; Yu, Qingbo; Liu, Junxiang; Qin, Qin; Xie, Huaqing; Yang, Fan; Duan, Wenjun

doi:10.2355/isijinternational.isijint-2016-402

Cited by 22 publications

(8 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Ca and Mg were also seen prominent in the XRD diagram of granulated slag because of which this type of slag has a dolomitic stoichiometry 12 . The higher presence of Ca in the granulated slag may have stimulated the separation of Fe and Si from 2FeO.SiO 2 for better slag reduction at high temperature, but a higher amount of Ca in the form of CaO may have also resulted in increasing the viscosity of the slag due to the higher presence of insoluble solid in the slag 23 . The presence of magnesium and aluminium also indicates that their oxides might be the residues of magnetite present in the slag.…”

Section: Resultsmentioning

confidence: 99%

Archaeometallurgical characterisation of ancient copper slags from pre‐Harappan site, Kunal, India

Kanth

Singh²,

Mani

2022

Analytical Science Advances

View full text Add to dashboard Cite

The copper slags collected during the excavation of the Early Harappan period site at Kunal in northern India were studied to understand the advancement of smelting technology and the achieved smelting temperature in the furnace by undertaking archaeometallurgical characterisation of the slags. In this research, two types of slags such as slag with glassy appearance and granulated slag were selected for the study. The microscopic structure and distribution of slag components were investigated using optical microscopy and phase determination was done by X‐ray diffraction (XRD). Chemical characterization of the slags was conducted using scanning electron microscopy–energy‐dispersive X‐ray spectroscopy, X‐ray fluorescence analysis (XRF) and inductively coupled plasma–mass spectrometry to build a complete chemical profile of the slags. Fayalite and magnetite were the dominant phases in the glassy slag; however, the granulated slag showed the dominance of calcite as secondary phase which reflected the dolomitic stoichiometry of the slag. The presence of dominant fayalite mineral phase as detected by XRD and higher concentration of iron as detected by XRF indicated the reducing environment during the smelting process. In this study, the absence of sulphur is reported which is unique to the ancient copper slag.

show abstract

Section: Resultsmentioning

confidence: 99%

Archaeometallurgical characterisation of ancient copper slags from pre‐Harappan site, Kunal, India

Kanth

Singh²,

Mani

2022

Analytical Science Advances

View full text Add to dashboard Cite

show abstract

“…Nonisothermal and isothermal kinetics study methods have been carried out on the kinetics and mechanism research of gaseous and solid reduction of iron oxides. , Nowadays, the diffusion model, Avrami–Erofeev equation (random nucleation) model, shrinking core model, and chemical reaction model have been applied to describe different reaction mechanisms. ,,, In particular, carbon-based direct reduction of iron ores has been studied for decades . Many different direct reduction mechanism functions have been established .…”

Section: Resultsmentioning

confidence: 99%

Effects of CaO on Two-Step Reduction Characteristics of Copper Slag Using Biochar as Reducer: Thermodynamic and Kinetics

Zuo

Luo

et al. 2019

Energy Fuels

Self Cite

View full text Add to dashboard Cite

A technology system of copper slag thermal energy recovery and direct reduction (TER-DR) was proposed in this paper. The effects of CaO addition and C/O on the reduction characteristics were discussed. CaO can improve the reduction reaction of 2FeO•SiO 2 in copper slag and decreases the Gibbs free energy significantly. Besides, CaO improves the reduction mass loss (RML) and reduction rate, and peaks of the DTG curves move to lower temperature. The temperature of the DTG peaks decreases by 54 K. CaO decreases the activation energy. When CaO/S is 0.3, copper slag has the highest RML and reduction rate and lowest activation energy. Furthermore, with an increase of the biochar addition ratio, values of RML and DTG peaks increased sharply. On the basis of Coats−Redfern method, reaction kinetics copper slag reduction is acquired: 960−1478 K, C and [O] diffusion in copper slag is the reaction rate-controlling step; 1478−1703 K, chemical reaction rate of C and CO with [O] in copper slag is the rate-controlling step. Mechanism function does not change with the variation of CaO/S and C/O in experiments. Without CaO addition, CO 2 is difficult to be produced; when CaO is added, reduction of the 2FeO• SiO 2 rate is improved. CaO•SiO 2 , CO 2 , and CO will be produced together.

show abstract

“…The mass ratio of the copper slag to CaO is based on the molar ratio of SiO 2 and CaO. In this experiment, the molar ratios of C/O and CaO/SiO 2 , regarded as the optimum reaction conditions, were all 1.0, and based on previous experimental results (Zuo et al, 2017;Zuo et al, 2020b). The masses of lignite and CaO were calculated based on Eqs 7, 8.…”

Section: Direct Reduction and Smelting Separationmentioning

confidence: 99%

Element Distribution and Migration Behavior in the Copper Slag Reduction and Separation Process

et al. 2021

Self Cite

View full text Add to dashboard Cite

Copper slag is a solid pollutant with high recyclability. Reduction and separation are regarded as effective disposal methods. However, during the melting process, the separation and migration behavior of elements in the copper slag is complicated. Thus, the formation of pollutants cannot be controlled merely by optimizing the operation parameters. The elemental distribution and migration behavior are discussed in this work. In reduction experiments, the copper slag smelting liquid was divided into three layers: a reduction slag layer, a reactive boundary layer, and an iron ingot layer. Reduction slag and ingot iron were on the top and bottom of the liquid, respectively. Residual carbon oozed at the interface. C can react with reducible “O” atoms, which exist in 2FeO·SiO2, Fe3O4, and CuO. Meanwhile, CO was generated and overflowed from the liquid layer. After reduction by C or CO, metallic iron and copper were produced and migrated to the iron ingot layer. In the liquid, S gradually diffused into the upper layer. Some of the ZnO and CuS spilled from the liquid into the flume. After reduction, CaO·SiO2 was generated and moved to the upper layer.

show abstract

Effects of CaO on Reduction of Copper Slag by Biomass Based on Ion and Molecule Coexistence Theory and Thermogravimetric Experiments

Cited by 22 publications

References 18 publications

Archaeometallurgical characterisation of ancient copper slags from pre‐Harappan site, Kunal, India

Archaeometallurgical characterisation of ancient copper slags from pre‐Harappan site, Kunal, India

Effects of CaO on Two-Step Reduction Characteristics of Copper Slag Using Biochar as Reducer: Thermodynamic and Kinetics

Element Distribution and Migration Behavior in the Copper Slag Reduction and Separation Process

Contact Info

Product

Resources

About