Production of precipitated calcium carbonate (PCC) from steelmaking slag for fixation of CO₂

A1 Originalartikel i en vetenskaplig tidskrift (referentgranskad)


Interna författare/redaktörer


Publikationens författare: Arshe Said, Hannu-Petteri Mattila, Mika Järvinen, Ron Zevenhoven
Förläggare: ELSEVIER SCI LTD
Publiceringsår: 2013
Tidskrift: Applied Energy
Tidskriftsakronym: APPL ENERG
Volym: 112
Artikelns första sida, sidnummer: 765
Artikelns sista sida, sidnummer: 771
Antal sidor: 7
ISSN: 0306-2619
eISSN: 1872-9118


Abstrakt

Producing precipitated calcium carbonate (PCC) from steelmaking slag is a technology that contributes to the reduction of carbon dioxide emissions from iron and steel industries. While the carbon dioxide emissions from the sector are large, it could benefit from this option by utilizing its own by-products, i.e. steelmaking slags for fixation of CO2. Since the calcium content of the steelmaking slag is high, a calcium carbonate precipitate can be produced with the method which we have recently developed, and, if fulfilling the requirements (e.g. purity and crystal shape), it can be utilized as PCC. Therefore, the objective of this study is to further evaluate the feasibility of this method. Calcium was extracted selectively from the slag with aqueous solution of ammonium salt (NH4NO3, CH3COONH4 or NH4Cl) in an extraction reactor. After removal of the residual slag, the calcium-rich solution reacted with CO2 in a carbonation reactor producing PCC. Based on the experimental results, the slag's grain size has a clear effect on the calcium extraction efficiency; the smaller the steel converter slag's grain size, the larger the surface area, and the better the mass transfer rate which in turn results in a higher extraction efficiency. Grinding to smaller sizes is therefore one strategy towards improved efficiencies and chemical conversion rates. Solid to liquid ratio is another important parameter for improving extraction efficiency. The smallest solid to liquid ratio 5 g/l resulted in the maximum calcium extraction efficiency (73%) while the highest solid to liquid ratio 100 g/l resulted in the lowest extraction efficiency (6%). Consequently this option will be operationally expensive because of larger reactor volumes. The PCC produced from the calcium rich solution is comparable to the PCC produced with conventional methods.


Nyckelord

Extraction of calcium, Mineral carbonation, Precipitated calcium carbonate (PCC), Steelmaking slag

Senast uppdaterad 2020-20-01 vid 03:31