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Etude du comportement hydraulique d'une gehlénite synthétique et de l'élimination d'inclusions de chaux, en vue de la valorisation de deux sous-produits de la sidérurgie : les laitiers cristallisés et les scories issues du procédé Linz-Donawitz

Abstract : In a first part, we studied the hydraulic reactivity of gehlenite, principal component of the crystallized slags, with the principal components of Portland cements, i.e. the silicates and the tricalcium aluminates and the dicalcium silicate, as well as with aluminates CA and C12A7. We showed the inertia of gehlenite when it is used alone and a low reactivity in the presence of the additions, mainly with C3S, where the formation of C4ACH11 confirms the surface hydraulic reactivity of gehlenite. Tests in basic environment confirmed that the increase in the alkalinity of the environment promotes the hydration of gehlenite. It is shown that the reactivity of gehlenite increases when it is crushed finely; there is then hydrated gehlenite formation C2ASH8. The mechanical performances of mortars containing crystallized slags (made up primarily of gehlenite) and cements such as the use of crystallized slags, when they are crushed finely, is possible. In one second part, our objective went on tests of neutralization of the quicklime present in slags of steel-works. It was noted that the addition of acid salts to slag is effective only at the time of th,e attack of the slags crushed by the acid solutions. The formation of the hydrates oflarnite [beta]C2S (portlandite and ettringite), allows the direct contact between acid salts and the lime which then is completely neutralized. Tests at high temperature were carried out on sintered pastilles, placed under conditions close to those of the converter. The results obtained by addition of 5 % of alumina-silica mixtures or fly ash showed that the free lime had completely disappeared to be trapped in the form of silicate and of aluminate. With the additives less rich in acid oxides, like the crystallized or granulated slags or aluminate C12A7, the capacity of inertage is limited.
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http://docnum.univ-lorraine.fr/prive/SCD_T_2000_0133_PRIN_FERREIRA.pdf
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https://hal.univ-lorraine.fr/tel-01746499
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Submitted on : Thursday, March 29, 2018 - 10:39:05 AM
Last modification on : Wednesday, March 24, 2021 - 10:24:04 AM

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Laurence Prin-Ferreira. Etude du comportement hydraulique d'une gehlénite synthétique et de l'élimination d'inclusions de chaux, en vue de la valorisation de deux sous-produits de la sidérurgie : les laitiers cristallisés et les scories issues du procédé Linz-Donawitz. Autre [cond-mat.other]. Université Henri Poincaré - Nancy 1, 2000. Français. ⟨NNT : 2000NAN10133⟩. ⟨tel-01746499⟩

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