| In recent years, the technology of steel-making in China has made new progress. To begin with, in order to improve product efficiency, steel ladle above 90 tons is increased rapidly. At the same time, the requirement on high-purity and high-cleanliness steel is increasingly high, and refining steel is used widely. Those directly leads to the increment of tapping temperature (For instance, in HanDan Steel Company, the tapping temperature is even up to 1700癈 ) and steel water being kept in ladle longer than before. As a result, steel ladle working condition becomes increasingly bad. In order to increase serving life of ladle, to reduce production costs and the labour intensity, it is necessary to develop alkaline gunning mixes for part repairing.Based on analyzing the main composition of ladle slagline and some corresponding atlas, the materials such as magnesite, magnesite-sinter-calcium-oxide, alumina-magnesite spinel, magnesite-chrome spinel and chromite are respectively used as the main material composition. Through experimenting, the best materials is ascertained, and two-double spraying method is expounded, in which magnesite-chrome spinel, chromite are the most suitable inboard material, and alumina-magnesite spinel is the most suitable outboard material. Through theoretically deducing and consulting other research, such grain size separation as follows are ascertained: the inboard material is composed of powder, in the outboard material, big particle (3mm~1mm) : small particle (1mm~0.088mm) : powder (<0.088mm) =35 : 30 : 35.Through studying, the best binder and their dose is ascertained: every 100g chromite needs 10g Al (H2PO4) 3 liquor, every 100g magnesite-chrome spinel needs 17g (NaPO3) n liquor, and every 100g alumina-magnesite spinel needs 13g (NaPO3)n liquor. Beside this, some suitable addition is very important to the properties of gunning refractor. Theexperiment's conclusion indicates that adding some alumina super-powder makes conglutinant strength increase by 5%.
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