US 11,932,914 B2
Process for manufacturing a slag conditioning agent for steel desulfurization
Eric Perrin, Paris (FR); and Souliyann Chunlamani, Brussels (BE)
Assigned to S.A. LHOIST RECHERCHE ET DEVELOPPEMENT, Ottignies-Louvain-la-Neuve (BE)
Appl. No. 17/309,680
Filed by S.A. Lhoist Recherche et Developpement, Ottignies-Louvain-la-Neuve (BE)
PCT Filed Dec. 17, 2019, PCT No. PCT/EP2019/085338
§ 371(c)(1), (2) Date Jun. 15, 2021,
PCT Pub. No. WO2020/127039, PCT Pub. Date Jun. 25, 2020.
Claims priority of application No. 18213132 (EP), filed on Dec. 17, 2018.
Prior Publication US 2021/0395846 A1, Dec. 23, 2021
Int. Cl. C21C 7/064 (2006.01)
CPC C21C 7/0645 (2013.01) 7 Claims
 
1. Process for manufacturing a slag conditioning agent for steel desulfurization comprising the steps of:
providing a slag material obtained from secondary steelmaking process, in particular a slag material obtained after an Al-killing steel process, said slag material comprising at least calcium, aluminum, iron, moisture, and a phase of calcium aluminate;
mixing said slag material with quicklime particles having a predetermined maximum particle size, and drying said slag material by having at least a pan of the quicklime particles reacting at least partially with a moisture contained in the slag material thereby obtaining a first blend comprising slag material, hydrated lime and optionally unreacted quicklime,
sieving said first blend at a cut-size superior or equal to said predetermined minimum particle size of said quicklime to remove a passing fraction of said first blend from a retained dried fraction of said first blend, said passing fraction having a maximum particle size lower than said cut-size and comprising a majority of said hydrated time; and
mixing said retained dried fraction with a composition having an A2O3 mass fraction of at least 80 wt % relative to the weight of the composition, and collecting a slag conditioning agent having an equivalent mass ratio CaO/Al2O3 comprised between 0.55 and 1.5.