CO–H<sub>2</sub> Gas-Based Reduction Behavior of Cr-Rich Electroplating Sludge Mixed with Iron Ore Powder
Cr-rich electroplating sludge (CRES) is a complicated solid waste with high contents of chromium and iron. It can be used as a main feed of the FINEX ironmaking process, which requires gas-based reduction before smelting reduction to produce molten iron with the proper addition of iron ore powder. I...
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MDPI AG
2024-03-01
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| Series: | Metals |
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| Online Access: | https://www.mdpi.com/2075-4701/14/3/325 |
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| author | Jian Zhang Zhiwei Peng Lingyun Yi Mingjun Rao |
| author_facet | Jian Zhang Zhiwei Peng Lingyun Yi Mingjun Rao |
| author_sort | Jian Zhang |
| collection | DOAJ |
| description | Cr-rich electroplating sludge (CRES) is a complicated solid waste with high contents of chromium and iron. It can be used as a main feed of the FINEX ironmaking process, which requires gas-based reduction before smelting reduction to produce molten iron with the proper addition of iron ore powder. In this study, the CO–H<sub>2</sub> gas-based reduction behavior of CRES mixed with iron ore powder was evaluated between 700 °C and 850 °C, with a focus on the variations of key components containing Fe, Cr, and S with reduction temperature and time. It was found that the iron oxides in CRES had stepwise conversions to metallic iron as the reduction reaction proceeded. The iron metallization degree of the mixture of CRES and iron ore powder increased obviously below 750 °C and then grew minorly with the further increase of temperature. Moreover, this index varied similarly with an extension of reduction time up to 80 min. After reduction at 750 °C for 60 min with the volume concentration of H<sub>2</sub> of 30% and flow rate of 160 mL/min, the iron metallization degree reached 79.08%. The rate in the process was limited by a chemical reaction with an activation energy of 41.32 kJ/mol. Along with the stepwise reduction of iron oxides to metallic iron, the chromium hydroxide and sulfates in CRES were reduced to Cr<sub>2</sub>O<sub>3</sub> and sulfites and sulfides, respectively. |
| first_indexed | 2024-04-24T18:01:15Z |
| format | Article |
| id | doaj.art-291c92d0e0cd4c6e9747a2f40b073485 |
| institution | Directory Open Access Journal |
| issn | 2075-4701 |
| language | English |
| last_indexed | 2024-04-24T18:01:15Z |
| publishDate | 2024-03-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Metals |
| spelling | doaj.art-291c92d0e0cd4c6e9747a2f40b0734852024-03-27T13:54:26ZengMDPI AGMetals2075-47012024-03-0114332510.3390/met14030325CO–H<sub>2</sub> Gas-Based Reduction Behavior of Cr-Rich Electroplating Sludge Mixed with Iron Ore PowderJian Zhang0Zhiwei Peng1Lingyun Yi2Mingjun Rao3School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, ChinaSchool of Minerals Processing and Bioengineering, Central South University, Changsha 410083, ChinaSchool of Minerals Processing and Bioengineering, Central South University, Changsha 410083, ChinaSchool of Minerals Processing and Bioengineering, Central South University, Changsha 410083, ChinaCr-rich electroplating sludge (CRES) is a complicated solid waste with high contents of chromium and iron. It can be used as a main feed of the FINEX ironmaking process, which requires gas-based reduction before smelting reduction to produce molten iron with the proper addition of iron ore powder. In this study, the CO–H<sub>2</sub> gas-based reduction behavior of CRES mixed with iron ore powder was evaluated between 700 °C and 850 °C, with a focus on the variations of key components containing Fe, Cr, and S with reduction temperature and time. It was found that the iron oxides in CRES had stepwise conversions to metallic iron as the reduction reaction proceeded. The iron metallization degree of the mixture of CRES and iron ore powder increased obviously below 750 °C and then grew minorly with the further increase of temperature. Moreover, this index varied similarly with an extension of reduction time up to 80 min. After reduction at 750 °C for 60 min with the volume concentration of H<sub>2</sub> of 30% and flow rate of 160 mL/min, the iron metallization degree reached 79.08%. The rate in the process was limited by a chemical reaction with an activation energy of 41.32 kJ/mol. Along with the stepwise reduction of iron oxides to metallic iron, the chromium hydroxide and sulfates in CRES were reduced to Cr<sub>2</sub>O<sub>3</sub> and sulfites and sulfides, respectively.https://www.mdpi.com/2075-4701/14/3/325hazardous solid wasteelectroplating sludgegas-based reductionchromiumiron |
| spellingShingle | Jian Zhang Zhiwei Peng Lingyun Yi Mingjun Rao CO–H<sub>2</sub> Gas-Based Reduction Behavior of Cr-Rich Electroplating Sludge Mixed with Iron Ore Powder Metals hazardous solid waste electroplating sludge gas-based reduction chromium iron |
| title | CO–H<sub>2</sub> Gas-Based Reduction Behavior of Cr-Rich Electroplating Sludge Mixed with Iron Ore Powder |
| title_full | CO–H<sub>2</sub> Gas-Based Reduction Behavior of Cr-Rich Electroplating Sludge Mixed with Iron Ore Powder |
| title_fullStr | CO–H<sub>2</sub> Gas-Based Reduction Behavior of Cr-Rich Electroplating Sludge Mixed with Iron Ore Powder |
| title_full_unstemmed | CO–H<sub>2</sub> Gas-Based Reduction Behavior of Cr-Rich Electroplating Sludge Mixed with Iron Ore Powder |
| title_short | CO–H<sub>2</sub> Gas-Based Reduction Behavior of Cr-Rich Electroplating Sludge Mixed with Iron Ore Powder |
| title_sort | co h sub 2 sub gas based reduction behavior of cr rich electroplating sludge mixed with iron ore powder |
| topic | hazardous solid waste electroplating sludge gas-based reduction chromium iron |
| url | https://www.mdpi.com/2075-4701/14/3/325 |
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