Influence of the firing conditions upon the heat resistance of ceramic articles

Павлов, В. Ф.; Алексеева, Л. Л.; Mitrokhin, V. S.

doi:10.1007/bf00676868

Cited by 3 publications

(2 citation statements)

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“…The equilibrium phase diagram of the CuO–Al 2 O 3 binary system indicates that two aluminates (CuAl 2 O 4 and CuAlO 2 ) can coexist in a mixture of CuO and alumina heated to temperatures above 1000 °C. However, because the dwelling time of the ceramic sintering process can vary from a few minutes to several hours, − the metal incorporation reactions are kinetically limited. The dominant mechanism for hosting copper in crystal structures under different thermal conditions should be unambiguously identified, if not also quantitatively evaluated.…”

Section: Introductionmentioning

confidence: 99%

Stabilization Mechanisms and Reaction Sequences for Sintering Simulated Copper-Laden Sludge with Alumina

Tang

Shih

2013

ACS Sustainable Chem. Eng.

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To stabilize copper-laden sludge using alumina-based ceramic raw materials, this study quantifies the copper transformation behavior during the sintering process. Results indicate crystallochemical incorporation of hazardous copper through the formation of copper aluminate spinel (CuAl2O4) and cuprous aluminate (CuAlO2). To quantify the copper transformation and reveal reaction sequences, CuO was mixed with γ-Al2O3 and α-Al2O3 precursors and fired at 1050–1150 °C for 15–180 min. The sintered products were examined using X-ray diffraction (XRD), and copper transformations into both aluminate phases were quantitatively determined through Rietveld refinement analysis of XRD data. When γ-Al2O3 was used, CuAlO2 was predominately generated from CuAl2O4 decomposition. However, CuAlO2 was largely generated by the interaction between CuO and α-Al2O3. This study also compared the sintering behavior of both precursor systems and observed the relatively slower decomposition of CuAl2O4 in the γ-Al2O3 system. The reoxidation of CuAlO2 into CuAl2O4 with an extended sintering time was detected in the α-Al2O3 system. The sample leachability analysis reveals that both CuAl2O4 and CuAlO2 structures were superior in copper stabilization compared to the oxide forms. Such results suggest reliable mechanisms of incorporating hazardous copper into a ceramic matrix and demonstrate the potential of using waste materials as part of ceramic raw materials to produce detoxified products.

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Section: Introductionmentioning

confidence: 99%

Stabilization Mechanisms and Reaction Sequences for Sintering Simulated Copper-Laden Sludge with Alumina

Tang

Shih

2013

ACS Sustainable Chem. Eng.

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“…To identify the potential phases responsible for the metal incorporation mechanisms in a 3-h short sintering scheme, the pelletized powder mixture samples were fired in a high-temperature furnace (LHT 02/16 LB, LBR, Nabertherm Inc.) for a fixed 3-h dwelling time at targeted sintering temperatures. 25,26 For the NiO + g-Al 2 O 3 system, these temperatures ranged from 1000 to 1450 C; for the CuO + g-Al 2 O 3 system, they ranged from 650 to 1150 C. After sintering, the samples were air-quenched and ground into powder for XRD analysis to determine the formations of the nickel-or copper-bearing aluminate phases. The diffraction patterns were collected using a Bruker D8 diffractometer (Bruker Co., Ltd.) equipped with a Cu X-ray tube operated at 40 kV and 40 mA.…”

Section: Metal Incorporation By Aluminatesmentioning

confidence: 99%

Prolonged toxicity characteristic leaching procedure for nickel and copper aluminates

Shih

Tang

2011

J. Environ. Monit.

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The toxicity characteristic leaching procedure (TCLP) is a regulatory testing method widely employed to evaluate the environmental friendliness of waste materials. TCLP analysis provides a fast, easy and economical way to determine the mobility of waste pollutants under simulated landfill conditions. Recent studies on metal stabilization have reported the potential for nickel and copper aluminates to form in thermal treatment conditions, and suggested a more reliable method of stabilizing hazardous metals, particularly when products are to be reused. There is thus an urgent need for a convenient and effective method of quantifying metal leachability and identifying the metal leaching behavior of sparingly soluble materials. In this study, standard TCLP analysis was modified into a prolonged leaching experiment to investigate the leaching behavior of nickel and copper oxides (NiO and CuO) and their aluminates (NiAl(2)O(4), CuAl(2)O(4) and CuAlO(2)). The results demonstrate the difficulty of differentiating the leachability of highly insoluble phases, such as NiO and NiAl(2)O(4), using the standard TCLP. The prolonged TCLP method, however, confirmed NiAl(2)O(4) to have a lower degree of intrinsic leachability than NiO and that it could be expected to undergo congruent dissolution under landfill conditions. For the more soluble copper system, the aluminates were still found to possess a much lower degree of leachability, and their leaching behavior to follow an incongruent dissolution pattern. The results of this study prove prolonged TCLP analysis to be a convenient and effective way to evaluate the environmental friendliness of metal waste and to identify the leaching behavior of waste materials.

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Phase transformation during the sintering of γ-alumina and the simulated Ni-laden waste sludge

Wang

Shih

Jiang

2012

Ceramics International

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Influence of the firing conditions upon the heat resistance of ceramic articles

Cited by 3 publications

References 1 publication

Stabilization Mechanisms and Reaction Sequences for Sintering Simulated Copper-Laden Sludge with Alumina

Stabilization Mechanisms and Reaction Sequences for Sintering Simulated Copper-Laden Sludge with Alumina

Prolonged toxicity characteristic leaching procedure for nickel and copper aluminates

Phase transformation during the sintering of γ-alumina and the simulated Ni-laden waste sludge

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