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Yang Z.,Hubei University | Qiao L.,Hubei University | He Y.,Hubei University | Tao H.,Hubei University | And 2 more authors.
Applied Mechanics and Materials | Year: 2013

Copper slag, containing more than 40 wt% iron, is often used for pavement of roads, building bricks and cement etc. The level of this traditional utilization technology is very poor. In this study, a new method of comprehensive utilization of copper slag was investigated. The iron of copper slag was recovered and the residual slag was transformed into glass-ceramics within the same process involving iron reduction, iron-glass separation and glass crystallization. The experimental results indicated that the ratio of iron recovery was more than 99% and the crystalline phase of the obtained glass-ceramics was diopside. With the extension of crystallization time, the content of crystalline phase and the size of crystals of the glass-ceramics increase. © (2013) Trans Tech Publications, Switzerland.

Yang Z.,Hubei University | Lin Q.,Hubei University | Lu S.,Hubei University | He Y.,Hubei University | And 2 more authors.
Ceramics International | Year: 2014

Glass-ceramics were synthesized successfully from iron-rich copper slag and the iron was recovered in the same process so that iron-rich copper slag was recycled efficiently. The influence of CaO/SiO2 ratio on the preparation of glass-ceramics was emphasized using differential scanning calorimetry (DSC), X-ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The results show that the residual iron concentration of the quenched glass is less than 1.43 mass% and Fe concentration in recovery of copper slag is more than 96.6 mass%, highlighting that the iron is extracted effectively from copper slag. Crystallization kinetics result shows an increase in the activation energies of crystallization with an increase in CaO/SiO2 ratio up to 0.38 and subsequently a decrease with further increase in CaO/SiO2 ratio up to 0.42. Anorthite with lamellar shape and diopside with irregular column shape are developed as the major phases in all the glass-ceramics samples with different CaO/SiO2 ratios. The increase in CaO/SiO2 ratio hinders the crystal growth of lamellar anorthite but benefits the formation of diopside crystals. For CaO/SiO2=0.42, the optimal comprehensive properties of the glass-ceramics are achieved: low porosity of 0.11%, low bibulous rate of 0.04%, high density of 2.75 g/cm and high hardness of 85.75 HBa. © 2013 Elsevier Ltd and Techna Group S.r.l.All rights reserved.

Yang Z.,Hubei University | Lin Q.,Hubei University | Xia J.,Hubei University | He Y.,Hubei University | And 2 more authors.
Journal of Alloys and Compounds | Year: 2013

In this paper, the glass-ceramics were prepared and the iron was recovered from the iron-rich copper slag in the same process, which includes slag-melting, iron-glass separation and glass-crystallization. The results show that the iron was separated from copper slag and the residual slag was transformed into light-color glass-ceramics successfully. The crystallization kinetics, crystal phase and microstructure of glass-ceramics heated at different crystallization temperatures between 900 °C and 1100 °C were estimated by DSC, FTIR, XRD and SEM. It is found that the crystallization of the glass samples takes place via surface crystallization mechanism. The major crystalline phase is anorthite and the minor phases are quartz and diopside, the size of which increases with the rise in crystallization temperature. The optimal physical-chemical properties are achieved at 950 °C, with bulk density of 2.69 g/cm 3, water absorption of 0.05% and porosity of 0.06%. © 2013 Elsevier B.V. All rights reserved.

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