Sulfur-Emission-Free Process of Molybdenum Carbide Synthesis by Lime-Enhanced Molybdenum Disulfide Reduction with Methane

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• 作者：Samad Ghasemi ; Mohammad Hasan Abbasi ; Ali Saidi ; Jae Yul Kim ; Jae Sung Lee
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2011
• 出版时间：December 7, 2011
• 年：2011
• 卷：50
• 期：23
• 页码：13340-13346
• 全文大小：1017K
• 年卷期：v.50,no.23(December 7, 2011)
• ISSN：1520-5045

文摘

To investigate a sulfur-emission-free process of molybdenum carbide synthesis from molybdenite, the reaction pathways of MoS₂ reduction with methane in the presence of lime (CaO) have been studied. A mixture of MoS₂ + 2CaO was reduced isothermally with CH₄ in a microreactor, and the composition of effluent gases and the reduced fraction were determined as a function of reaction time. Analysis of the solid phase at different reaction times at 800 掳C showed the formation of CaMoO₄ as an intermediate phase. Hence, the reaction pathways proposed for reduction of MoS₂ + CaO with CH₄ involves the direct reduction of MoS₂ with CH₄ to form Mo₂C and sulfur-containing gases. The sulfur-containing gases are captured by CaO to form CaS, CO(g), CO₂(g), and H₂O(g). The unreacted MoS₂ is oxidized by CO₂(g) and H₂O(g) to form MoO₃(g), which reacted with CaO to form CaMoO₄ on CaO particles. Finally, CaMoO₄ and remaining MoS₂ are further reduced with CH₄. Characterization of solid samples was carried out by XRD, CHN, and FE-SEM equipped with EDS, providing results consistent with the proposed reaction pathways. Carbon content of solid sample increased with reduction time, and in fully reduced sample at 800 掳C it was well above the stoichiometric amount indicating considerable excess carbon deposition due to CH₄ cracking.