Converter retaining operation method of preventing splash slag and reducing iron loss

Abstract

The present invention discloses that before and during tapping, carbon containing reductant coal powder, coke powder or graphite powder is added to the surface of slag liquid inside converter so as to reduce FeO in slag liquid, raise slag viscosity and smelting point and protect converter. The method is simple and low in cost, and can reduce steel making cost of converter obviously.

Description

Technical field [0001] The invention relates to a converter slag splashing furnace protection process, in particular to a converter slag splashing furnace protection operation method for reducing iron loss. Background technique [0002] Splashing the furnace to protect the furnace requires "splashing, sticking, and not falling off". "Splashing" means to pour the slag as little as possible, keep the slag, and make a fuss about smelting a hit; "sticky" means to ensure that the slag has a certain viscosity, control the peroxide, control the end carbon, and reduce the tapping temperature; "No drop" means to increase the melting point of the slag, reduce the iron oxide content, and increase the alkalinity and magnesium oxide content. The raw materials used in my country's converter steelmaking plants are very different in the final slag composition due to the large differences in production products and process systems. [0003] The main components MgO, TFe and alkalinity (CaO / SiO) th...

AI Technical Summary

Problems solved by technology

Even so, due to the large number of smelted steels and the large passive range of end point components, after adopting the technology of slag splashing to protect the furnace, only Baosteel still has 7% of the furnaces whose MgO content in the end slag has not reached saturation, which directly affects the slag splash protection. The effect of the furnace

[0005] At present, the operation method of slag splashing to protect the furnace is adopted at home and abroad: one is to add light-burned magnesium balls and light-burned dolomite (or magnesite) in the early stage or process of smelting, and make the slag sticky at the end of smelting, and the final slag of the converter is The content of MgO can meet the requirements of the refractoriness of the slag-splashing layer. When the superheat of the slag is not high, nitrogen can be injected directly after tapping to carry out the slag splashing operation; another method is that the MgO content in the slag after tapping cannot reach For the value required by the slag splash layer, it is necessary to add a slag adjusting agent to increase the MgO content in the slag, so that when the slag reaches a certain viscosity, the slag splashing protection operation is carried out, but the difficulty of slag adjustment after tapping is that the amount of slag and the composition of the slag are different. Easy to estimate accurately, adding slag is not easy to melt completely

[0006] Both of the above-mentioned processes have serious deficiencies: in order to balance the adverse effects of FeO, excessive magnesium material is added, and the consumption of slag is too large. Because the content of MgO in the slag is higher than that of the traditional process, the viscosity of the slag increases. From a kinetic point of view, How much is not conducive to the removal of P and S; on the one hand, it reduces the spreadability of the slag and increases the blowing loss; on the other hand, it increases the iron loss in the slag significantly (Appendix III), which is because the iron beads in the slag are difficult to settle as the viscosity of the slag increases. to

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