Carbonation of EAF Stainless Steel Slag and Its Effect on Chromium Leaching Characteristics
EAF stainless steel slag (EAF slag) is one kind of chromium-bearing metallurgical solid waste, which belongs to alkaline steel slag, and contains a large number of alkaline mineral phases. The carbonation activity of these minerals gives EAF slag the capability to effectively capture CO<sub>2&...
| Main Authors: | , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2021-12-01
|
| Series: | Crystals |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2073-4352/11/12/1498 |
| _version_ | 1797505677060472832 |
|---|---|
| author | Ya-Jun Wang Meng-Jie Tao Jun-Guo Li Ya-Nan Zeng Song Qin Shao-Hua Liu |
| author_facet | Ya-Jun Wang Meng-Jie Tao Jun-Guo Li Ya-Nan Zeng Song Qin Shao-Hua Liu |
| author_sort | Ya-Jun Wang |
| collection | DOAJ |
| description | EAF stainless steel slag (EAF slag) is one kind of chromium-bearing metallurgical solid waste, which belongs to alkaline steel slag, and contains a large number of alkaline mineral phases. The carbonation activity of these minerals gives EAF slag the capability to effectively capture CO<sub>2</sub>. In this paper, EAF slag samples with different carbonation degrees were prepared by the slurry-phase accelerated carbonation route. The mineralogical identification analysis was used to qualitatively and semi-quantitatively determine the types and contents of the carbonatable mineral phases in the EAF slag. The sequential leaching test was used to study the chromium leachabilities in EAF slags with different carbonation degrees. The results showed that the main minerals with carbonation activity in EAF slag were Ca<sub>3</sub>Mg(SiO<sub>4</sub>)<sub>2</sub> and Ca<sub>2</sub>SiO<sub>4</sub>, with mass percentages of 56.9% and 23%, respectively. During the carbonation process, Ca<sub>2</sub>SiO<sub>4</sub> was the main reactant and calcite was the main product. As the degree of carbonation increased, the pH of the EAF slags’ leachate gradually decreased while the redox potential (Eh) gradually increased. At the same time, a large amount of Ca<sup>2+</sup> in the EAF slag combined with CO<sub>2</sub> to form slightly soluble calcium carbonate, which led to a significant decrease in the conductivity of the leachate. With the gradual increase in carbonation ratio, the leachability of chromium in the EAF slag first decreased and then increased, and reached its lowest value when the CO<sub>2</sub> uptake ratio was 11.49%. |
| first_indexed | 2024-03-10T04:21:52Z |
| format | Article |
| id | doaj.art-5cd28568cfd94dda8bd0fae6ce0d9d91 |
| institution | Directory Open Access Journal |
| issn | 2073-4352 |
| language | English |
| last_indexed | 2024-03-10T04:21:52Z |
| publishDate | 2021-12-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Crystals |
| spelling | doaj.art-5cd28568cfd94dda8bd0fae6ce0d9d912023-11-23T07:48:35ZengMDPI AGCrystals2073-43522021-12-011112149810.3390/cryst11121498Carbonation of EAF Stainless Steel Slag and Its Effect on Chromium Leaching CharacteristicsYa-Jun Wang0Meng-Jie Tao1Jun-Guo Li2Ya-Nan Zeng3Song Qin4Shao-Hua Liu5School of Metallurgy and Energy, North China University of Science and Technology, Tangshan 063009, ChinaSchool of Metallurgy and Energy, North China University of Science and Technology, Tangshan 063009, ChinaSchool of Metallurgy and Energy, North China University of Science and Technology, Tangshan 063009, ChinaSchool of Metallurgy and Energy, North China University of Science and Technology, Tangshan 063009, ChinaSchool of Metallurgy and Energy, North China University of Science and Technology, Tangshan 063009, ChinaSchool of Metallurgy and Energy, North China University of Science and Technology, Tangshan 063009, ChinaEAF stainless steel slag (EAF slag) is one kind of chromium-bearing metallurgical solid waste, which belongs to alkaline steel slag, and contains a large number of alkaline mineral phases. The carbonation activity of these minerals gives EAF slag the capability to effectively capture CO<sub>2</sub>. In this paper, EAF slag samples with different carbonation degrees were prepared by the slurry-phase accelerated carbonation route. The mineralogical identification analysis was used to qualitatively and semi-quantitatively determine the types and contents of the carbonatable mineral phases in the EAF slag. The sequential leaching test was used to study the chromium leachabilities in EAF slags with different carbonation degrees. The results showed that the main minerals with carbonation activity in EAF slag were Ca<sub>3</sub>Mg(SiO<sub>4</sub>)<sub>2</sub> and Ca<sub>2</sub>SiO<sub>4</sub>, with mass percentages of 56.9% and 23%, respectively. During the carbonation process, Ca<sub>2</sub>SiO<sub>4</sub> was the main reactant and calcite was the main product. As the degree of carbonation increased, the pH of the EAF slags’ leachate gradually decreased while the redox potential (Eh) gradually increased. At the same time, a large amount of Ca<sup>2+</sup> in the EAF slag combined with CO<sub>2</sub> to form slightly soluble calcium carbonate, which led to a significant decrease in the conductivity of the leachate. With the gradual increase in carbonation ratio, the leachability of chromium in the EAF slag first decreased and then increased, and reached its lowest value when the CO<sub>2</sub> uptake ratio was 11.49%.https://www.mdpi.com/2073-4352/11/12/1498EAF slagleachingcarbonationchromiummineral phase |
| spellingShingle | Ya-Jun Wang Meng-Jie Tao Jun-Guo Li Ya-Nan Zeng Song Qin Shao-Hua Liu Carbonation of EAF Stainless Steel Slag and Its Effect on Chromium Leaching Characteristics Crystals EAF slag leaching carbonation chromium mineral phase |
| title | Carbonation of EAF Stainless Steel Slag and Its Effect on Chromium Leaching Characteristics |
| title_full | Carbonation of EAF Stainless Steel Slag and Its Effect on Chromium Leaching Characteristics |
| title_fullStr | Carbonation of EAF Stainless Steel Slag and Its Effect on Chromium Leaching Characteristics |
| title_full_unstemmed | Carbonation of EAF Stainless Steel Slag and Its Effect on Chromium Leaching Characteristics |
| title_short | Carbonation of EAF Stainless Steel Slag and Its Effect on Chromium Leaching Characteristics |
| title_sort | carbonation of eaf stainless steel slag and its effect on chromium leaching characteristics |
| topic | EAF slag leaching carbonation chromium mineral phase |
| url | https://www.mdpi.com/2073-4352/11/12/1498 |
| work_keys_str_mv | AT yajunwang carbonationofeafstainlesssteelslaganditseffectonchromiumleachingcharacteristics AT mengjietao carbonationofeafstainlesssteelslaganditseffectonchromiumleachingcharacteristics AT junguoli carbonationofeafstainlesssteelslaganditseffectonchromiumleachingcharacteristics AT yananzeng carbonationofeafstainlesssteelslaganditseffectonchromiumleachingcharacteristics AT songqin carbonationofeafstainlesssteelslaganditseffectonchromiumleachingcharacteristics AT shaohualiu carbonationofeafstainlesssteelslaganditseffectonchromiumleachingcharacteristics |