Abstract
The effect of microwave-supported leaching of electric arc furnace (EAF) slag by ammonium salts was investigated to improve calcium leaching ratio for CO2 mineral sequestration process. The results show that the calcium leaching ratio from EAF slag at the constant temperature in the microwave field increases about 10% than that under the water bath at the same leaching time. The greater the microwave power, the higher the impact of calcium leaching rate, which proves that microwave treatment can improve the leaching ratio of calcium. The rapid calcium leaching step (up to 5 min) is possibly due to the easy reaction of calcium silicate, while the slower calcium leaching step (after 5 min) is owing to the difficult reaction of calcium ferroaluminates for the hydrolysis of iron and aluminum. The leaching behaviors of magnesium and calcium ions affected by different leaching parameters are similar and the concentration of aluminum, iron and phosphorus can be neglected. Calcium ion is probably not precipitated in the real leaching solution from steel slag by ammonium chloride solution as its concentration is less than 0.32 mol/L. However, the concentration of magnesium ion starts to drop sharply when the pH value is higher than 10 and it has precipitated completely at pH value of 11.6.
Highlights
As fossil fuels will still be the main power source in the near future and its combustion would emit significant amounts of greenhouse gases, an economically viable approach to sequestrate CO2 is becoming more and more necessary
In order to improve the calcium leaching ratio from electric arc furnace (EAF) slag, this paper proposes the methods of assisting the calcium leaching in a microwave field and proves the possibility of improving calcium extraction efficiency from EAF
The leaching solutions are boiling within several minutes at constant power in the microwave field
Summary
As fossil fuels will still be the main power source in the near future and its combustion would emit significant amounts of greenhouse gases, an economically viable approach to sequestrate CO2 is becoming more and more necessary. The waste steelmaking slag are mainly used as fluxing agent of iron and steel smelting [4,5], fertilizer of agricultural production [6,7], construction materials (such as slag cement, brick, concrete and construction aggregate) [8], soil conditioner [9], as well as adsorbent of environmental protection [10]. For these applications only a small part of the slag can be utilized, especially in China, where the utilization rate of steel slag is only 22%, which is far behind the developed countries [11]. Large amounts of slag are stockpiled, which are costly and seriously harmful to the environment, such as damaging soil and vegetation or polluting air and water
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
