Dolomite pellets for adding to molten steel during converter refining - so dolomite enters slag to reduce attack on converter lining by aggressive slags

• Main Author: ARISTIDE BERTHET, GUY DENIER, PAUL-VICTOR RIBOUD ET PIERRE VAYSSIERE
• Format: Patent
• Language: English; French
• Published: 02.11.1979
• Subjects: CHEMISTRY; METALLURGY; METALLURGY OF IRON; PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OFWROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS

The pellets are made by the compaction of a mixt. contg. dolomite fines and a flux. The mixt. pref. contains by wt. 20-50% flux, which is esp. slag obtd. at the end of refining molten steel in an oxygen converter; and 30% slag is the esp. pref. amt. employed in the mixt. used to make the pellets. Instead of using slag, the flux may alternatively consists of manganese ore forming 20-50% of the mixt. employed to make the pellets. When the converter lining is based on MgO, is its usual to saturate the slag with roasted dolomite, so the attack by aggressive slags on the converter lining is reduced. The invention permits the use of fine material obtd. by roasting dolomite; such fine material was hitherto unsuitable for adding to the slag. L'invention concerne un produit dolomitique destiné à l'enfournement dans un convertisseur sidérurgique pour l'affinage de la fonte. L'invention se caractérise en ce que le produit se présente sous forme de boulets obtenus par compactage d'un mélange contenant essentiellement des fines de dolomie et un fondant constitué de préférence par du laitier de fin d'affinage au convertisseur de type LD ou par du minerai de manganèse.