Molten steel composite purifying agent for secondary refining and preparing method

Abstract

The compound purificant of external refining of molten steel and production method pertains to the field of smelting ferroalloy, in particular to the purificant dislodging impurity of molten steel and the purificant production method in external refining. The purificant comprises graphite, ferrosilicon, calcium-silicon and bauxite, according to the percentage of weight, is composed of the following components: the carbon content is from 18 per cent to 32 percent, the content of silicon is from 15 percent to 26 percent, the content of iron is from 3 percent to 8 percent, the content of calcium is from 3 percent to 10 percent, the content of aluminum oxide is from 26 percent to 38 percent, the content of water is less than or equal to 0.75 percent, and the remainder is the impurity and adhesion agent. The method producing the compound purificant of molten steel includes these steps of matching material, crashing, mixing, grain-making, drying, checking, piling and bagging, the purificant becomes graininess, and the grain size ranges from 3 mm to 30 mm. The method has the advantages of the extensive material, the convenient machining, the safety and reliability in production, storage and use, the strong capability of purifying molten steel, the low oxygen content of molten steel, promoting slag foaming, favorable submerged-arc operating in fining furnace, improving the thermal efficiency and the ladle age, the excellent effect of desulfurize, improving the recycle rate of manganese and silicon, saving the use of alloy.

Description

technical field [0001] The invention belongs to the treatment of molten iron alloys, in particular to a treatment agent for adding and removing impurities in steel by refining outside a furnace and a preparation method thereof. Background technique [0002] With the development of steelmaking technology, refining outside the furnace is an important part of modern steelmaking. In the process of tapping and refining, adding specific treatment agents can effectively deoxidize, desulfurize, and remove inclusions in steel, which is of great significance for improving the internal quality of steel, reducing production costs, and developing new products. Now a high-calcium series molten steel purifier is widely used, and its components and content by weight percentage are: 30-45% Ca, 12-15% Si, 10-25% C, ≤0.75H 2 O, although this type of molten steel purifying agent has a strong ability to purify molten steel and desulfurize [S], it has obvious shortcomings. Calcium carbide CaC 2...

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Problems solved by technology

Now a high-calcium series molten steel purifier is widely used, and its components and content by weight percentage are: 30-45% Ca, 12-15% Si, 10-25% C, ≤0.75H 2 O, although this type of molten steel purifying agent has a strong ability to purify molten steel and desulfurize [S], it has obvious shortcomings. Calcium carbide CaC 2 The content is large, and it is easy to deliquesce, and there are moisture-proof problems in production, storage and use, and there are potential safety hazards; the "Molten Steel Purifier" disclosed by the China Intellectual Property Office, application number: 02146152.x, its composition and content percentages are: calcium Ca, barium Ba, aluminum Al and silicon Si 5-18%, CaO 45-75%, Al 2 o 3 10-30%, SiO 2 ≤8%, this kind of molten steel purification agent has good ability to adsorb impurities in steel and remove [S], but the element containing [O] is too low, the ability to remove [O] is weak, the ability to purify molten steel is low, and the ability to foam slag Not strong

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