Corrosion mechanisms of magnesia-chrome refractories in copper slag and concurrent formation of hexavalent chromium

Xu, Tengteng; Xu, Yong; Li, Yawei; Sang, Shaobai; Wang, Qinghua; Zhu, Tianbin; Nath, Mithun; Zhang, Bo

doi:10.1016/j.jallcom.2019.01.314

Cited by 31 publications

(12 citation statements)

References 33 publications

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“…Newly formed (Mg, Cu) (Cr, Fe) 2 O 4 spinel dense layer between the slag and penetration layer effectively hinders further penetration of slag and well protects the specimens. TiO 2 addition can suppress the formation of Cr (VI) effectively [ 13 ].…”

Section: Introductionmentioning

confidence: 99%

Research and Development of Novel Refractory of MgO Doped with ZrO2 Nanoparticles for Copper Slag Resistance

et al. 2021

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This study investigates the corrosion mechanism on 100 wt.% MgO and 95 wt.% MgO with 5 wt.% nano-ZrO2 ceramic composites. First, MgO powder and powder mixtures (MgO + nano ZrO2) were uniaxially and isostatically pressed; then, they were sintered at 1650 °C. Corrosion by copper slag was studied in sintered samples. Physical properties, microstructure, and penetration of the slag in the refractory were studied. Results reveal that ZrO2 nanoparticles enhanced the samples’ densification, promoting grain growth due to diffusion of vacancies during the sintering process. Additionally, magnesia bricks were severely corroded, if compared with those doped with nano-ZrO2, mainly due to the dissolution of MgO grains during the chemical attack by copper slag.

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Section: Introductionmentioning

confidence: 99%

Research and Development of Novel Refractory of MgO Doped with ZrO2 Nanoparticles for Copper Slag Resistance

et al. 2021

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“…With the advancement of society and the development of science and technology, the performance requirements of refractory materials are getting higher and higher. Many researchers have studied and improved the corrosion resistance of refractories [ 2 , 3 , 4 , 5 , 6 ], thermal shock resistance [ 7 , 8 , 9 ], and anti-wear properties [ 10 ]. M. Yoshikawa et al [ 11 ] studied the erosion resistance of MgO-based spinel and Al 2 O 3 -based spinel refractories and found that these two refractories can replace Al 2 O 3 -Cr 2 O 3 refractories with low chromium content and are more suitable for alkali furnaces.…”

Section: Introductionmentioning

confidence: 99%

Analysis and Prediction of Corrosion of Refractory Materials by Sodium Salts during Waste Liquid Incineration—Thermodynamic Study

et al. 2020

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Incineration of high-content sodium salt organic waste liquid will corrode the refractory material in the incinerator, causing the refractory material to peel off and be damaged. A thermodynamics method was used to study the thermodynamic properties of three common sodium salts (NaCl, Na2CO3 and Na2SO4) on the corrosion of refractory materials (MgO·Cr2O3, MgO·Al2O3, Al2O3, MgO and Cr2O3). The results determined that MgO has the best corrosion resistance and is not corroded by the three sodium salts. On this basis, the thermodynamic corrosion experiments of NaCl corrosion of magnesium oxide at three temperatures of 600, 1000 and 1200 °C were carried out. Analysis of the corrosion product by X-ray diffraction (XRD) showed no corrosion product formation. Studies have shown that thermodynamic calculation can accurately predict the thermodynamic mechanism of alkali metal corrosion to refractory materials, and MgO is a good anti-alkali metal corrosion refractory material.

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“…Al 2 O 3 -Cr 2 O 3 refractories have high corrosion resistance due to the extremely low solubility and high chemical stability of Cr 2 O 3 in molten slag, and are therefore widely used as lining materials in incinerators, gasi ers, glass furnaces and non-ferrous smelting, etc. [1][2][3][4][5][6]. Recently, the Al 2 O 3 -Cr 2 O 3 refractories as castables are applied successfully since they are much more energy saving as well as convenient for installation and repairing compared with the bricks or shaped refractory products [7,8].…”

Section: Introductionmentioning

confidence: 99%

“…For the Cr 2 O 3 containing refractory linings, since the operation conditions and service atmosphere in a given furnace can hardly be changed in practical production, most of the related work have focused on Cr(VI) minimization using some additives at high temperatures. And the results suggested that acidic components such as SiO 2 , TiO 2 , Fe 2 O 3 and P 2 O 5 can effectively suppress the Cr(III) oxidation during thermal treatment of Cr 2 O 3 containing refractories [4,[23][24][25][26][27][28][29]. However, these oxide additives usually result in formation of low melting point phases in the matrix, which would obviously deteriorate the thermo-mechanical properties or slag corrosion resistance of the refractories [30][31][32].…”

Section: Introductionmentioning

confidence: 99%

“…Cr 2 O 3 -CaO-MgO system con rmed that composite spinel Mg(Al,Cr) 2 O 4 could co-exist with CA 2 ,where chromium existed in + 3 state[25, 34]. And for the magnesia-chrome refractories, adding a certain amounts of Al 2 O 3 and TiO 2 can effectively lower the concentrations of Cr(VI) as chromium mainly exists in the form of Mg(Al,Cr,Ti) 2 O 4 composite spinel[4].Recent research work demonstrated that for the Al 2 O 3 -CaO-Cr 2 O 3 castables, the CAC would facilitate the formation of very high concentrations of Cr(VI) compounds CaCrO 4 and Ca 4 Al 6 CrO 16 in air at mid-temperature (700-1100 o C), while nearly all the Cr 2 O 3 would convert into (Al 1 − x ,Cr x) 2 O 3 (0< x < 1) solid solution at 1500 o C, which lead to signi cant decrease of Cr(VI) compounds amounts [23]. Again, our recent research work showed that the formation of glasses phases in the Al 2 O 3 -CaO-Cr 2 O 3 castables could promote the (Al 1 − x ,Cr x ) 2 O 3 formation at high temperature, which drastically lowered the formation of Cr(VI) phases simultaneously [35].…”

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Inhibition of Cr(VI) in the Al2O3-CaO-Cr2O3 castables by using (Al1-x,Crx)2O3 solid solution

Xu¹,

Xu²,

Li³

et al. 2020

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Al2O3-CaO-Cr2O3 castables are required for various furnaces due to excellent corrosion resistance and sufficient early strength. However, generation of toxic Cr(VI) caused subsequent problems with disposal. The present work aimed at achieving Cr(VI) reduction by replacing Cr2O3 with (Al1 − x,Crx)2O3 solid solution. The phase evolutions and Cr(VI) formation in castables were systemically investigated. Compared with Cr2O3, stability of (Al1 − x,Crx)2O3 in CAC was much higher and improved gradually with Al3+ proportion. The substitution of Cr2O3 with (Al1 − x,Crx)2O3 completely inhibited CaCrO4 formation at 300–1100 oC, and drastically suppressed Ca4Al6CrO16 generation at 900–1300 °C. Thus, a remarkable Cr(VI) reduction of 98.1% could be achieved. Moreover, In comparison with CA and CA2, CA6 was much more stable, which would not take chemical reaction with (Al1 − x,Crx)2O3. Thus, incorporating some Al2O3 powders in Al2O3-CaO-Cr2O3 castables to form CA6 at temperature above 1300 oC was also essential for inhibiting Cr(VI) formation when using (Al1 − x,Crx)2O3 as substitute for Cr2O3.

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Corrosion mechanisms of magnesia-chrome refractories in copper slag and concurrent formation of hexavalent chromium

Cited by 31 publications

References 33 publications

Research and Development of Novel Refractory of MgO Doped with ZrO2 Nanoparticles for Copper Slag Resistance

Research and Development of Novel Refractory of MgO Doped with ZrO2 Nanoparticles for Copper Slag Resistance

Analysis and Prediction of Corrosion of Refractory Materials by Sodium Salts during Waste Liquid Incineration—Thermodynamic Study

Inhibition of Cr(VI) in the Al2O3-CaO-Cr2O3 castables by using (Al1-x,Crx)2O3 solid solution

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