Slurry-Phase Carbonation Reaction Characteristics of AOD Stainless Steel Slag

Argon oxygen decarburization stainless steel slag (AOD slag) has high mineral carbonation activity. AOD slag carbonation has both the resource utilization of metallurgical waste slag and the carbon reduction effect of CO2 storage. This paper aimed to study carbonation reaction characteristics of AOD slag. Under the slurry-phase accelerated carbonation route, the effect of stirring speed (r) and reaction temperature (T) on AOD slag’s carbonation was studied by controlling the reaction conditions. Mineral composition analysis and microscopic morphology analysis were used to explore the mineral phase evolution of AOD slag during the carbonation process. Based on the unreacted core model, the kinetic model of the carbonation reaction of AOD slag was analyzed. The results showed that the carbonation ratio of AOD slag reached its maximum value of 66.7% under the reaction conditions of a liquid to solid ratio (L/S) of 8:1, a CO2 partial pressure of 0.2 MPa, a stirring speed of 450 r.min−1, and a reaction temperature of 80 °C. The carbonation reaction of AOD slag was controlled by internal diffusion, and the calculated apparent activation energy was 22.28 kJ/mol.

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Carbonation of EAF Stainless Steel Slag and Its Effect on Chromium Leaching Characteristics

Crystals ◽

10.3390/cryst11121498 ◽

2021 ◽

Vol 11 (12) ◽

pp. 1498

Author(s):

Ya-Jun Wang ◽

Meng-Jie Tao ◽

Jun-Guo Li ◽

Ya-Nan Zeng ◽

Song Qin ◽

...

Keyword(s):

Stainless Steel ◽

Steel Slag ◽

Co2 Uptake ◽

Stainless Steel Slag ◽

Carbonation Process ◽

Mineral Phases ◽

Slurry Phase ◽

Soluble Calcium ◽

Eaf Slag ◽

Identification Analysis

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 CO2. 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 Ca3Mg(SiO4)2 and Ca2SiO4, with mass percentages of 56.9% and 23%, respectively. During the carbonation process, Ca2SiO4 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 Ca2+ in the EAF slag combined with CO2 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 CO2 uptake ratio was 11.49%.

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High-capacity adsorbents from stainless steel slag for the control of dye pollutants in water

Environmental Science and Pollution Research ◽

10.1007/s11356-020-12174-0 ◽

2021 ◽

Author(s):

Lorenzo Plaza ◽

Marta Castellote ◽

Roman Nevshupa ◽

Eva Jimenez-Relinque

Keyword(s):

Stainless Steel ◽

Steel Slag ◽

High Capacity ◽

Stainless Steel Slag ◽

Dye Pollutants

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Experimental Study on Precipitation Behavior of Spinels in Stainless Steel-Making Slag under Heating Treatment

Processes ◽

10.3390/pr7080487 ◽

2019 ◽

Vol 7 (8) ◽

pp. 487 ◽

Cited By ~ 5

Author(s):

Jianli Li ◽

Qiqiang Mou ◽

Qiang Zeng ◽

Yue Yu

Keyword(s):

Particle Size ◽

Stainless Steel ◽

Steel Slag ◽

Calcium Content ◽

Heating Time ◽

X Ray Diffraction ◽

Stainless Steel Slag ◽

Steel Making ◽

Heating Treatment ◽

The Stability

The stability of chromium in stainless steel slag has a positive correlation with spinel particle size and a negative correlation with the calcium content of the spinel. The effect of heating time on the precipitation of spinel crystals in the CaO-SiO2-MgO-Al2O3-Cr2O3-FeO system was investigated in the laboratory. Scanning electron microscopy with energy-dispersive and X-ray diffraction were adopted to observe the microstructure, test the chemical composition, and determine the mineral phases of synthetic slags, and FactSage7.1 was applied to calculate the crystallization process of the molten slag. The results showed that the particle size of the spinel crystals increased from 9.42 to 10.73 μm, the calcium content in the spinel crystals decreased from 1.38 at% to 0.78 at%, and the content of chromium in the spinel crystal increased from 16.55 at% to 22.78 at% with an increase in the heating time from 0 min to 120 min at 1450 °C. Furthermore, the species of spinel minerals remained constant. Therefore, an extension in the heating time is beneficial for improving the stability of chromium in stainless steel slag.

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