A kind of operation method of silicon reduction in molten iron

Abstract

The invention relates to the field of molten iron smelting, in particular to an operation method for molten iron silicon reduction. The operation method for the molten iron silicon reduction is characterized in that indirect oxidation silicon reduction operation of molten iron needed silicon reduction is conducted in a tundish, and the molten iron after the silicon reduction process returns to a smelting furnace for deoxidation, slight silicon increase or slight manganese increase is conducted to the molten iron in the smelting furnace, and the problem of overoxidation of the molten iron is solved. compared with the prior art, the operation method for the molten iron silicon reduction has the advantages that (1) by the adoption that the molten iron contacts with Na2CO3 powder to produce self-boiling effects, the fact that silicon in the molten iron reacts fully with oxide scales can be ensured to achieve targeted silicon reduction of the molten iron containing silicon, (2) a molten iron silicon reduction process is simple, silicon reduction effects are good, silicon reduction cost is low, (3) an operation step of 'silicon increase or manganese increase' is added to solve the problem of overoxidation of the molten iron after silicon reduction, comprehensive quality performance of the molten iron needed silicon reduction can be effectively ensured such as oxygen content, molten iron chilling property, and stability of flowability. The processed molten iron can be directly used for pouring cast iron products.

Description

technical field [0001] The invention relates to the field of molten iron smelting, in particular to an operation method for reducing silicon in molten iron. Background technique [0002] At present, in order to reduce the production cost of cast iron products, a large number of waste furnace materials are used in the molten iron smelting process, and the main technical problem brought about is that the "silicon" content exceeds the standard. During the molten iron smelting process, the "silicon" element mainly exists in the molten iron in two forms: solid solution free state and oxidized state. The "silicon" element in the oxidized state compound is insoluble in molten iron and exists in the slag, and the "silicon" element in the oxidized state can be removed by the slag removal operation method; while the "silicon" element existing in the molten iron in the form of solid solution and free state, if It can be "oxidized" to form SiO which is insoluble in molten iron 2 And i...

AI Technical Summary

Problems solved by technology

[0005] In the prior art, most of them use blowing, oxygen blowing, filling of desiliconization materials in the furnace, or flow down the silicon outside the furnace. The disadvantages of these operating methods are: 1) the process operation is complicated, and the cost of silicon reduction is high ( equipment cost and material cost), the silicon reduction effect is unstable, and the oxidation and burning loss of molten iron is not easy to control; 2) when the silicon is reduced in the furnace, the reaction product-slag is not easy to remove; 3) the existence of residual silicon reduction materials and the oxidation and burning of molten iron Improper control of the degree of damage can lead to a decline in the overall quality of molten iron; 4) The silicon reduction in the launder outside the furnace is unstable, and the reaction is largely affected by the flow rate of the molten iron and whether the silicon reduction material is fully reacted, which can easily lead to instability in the silicon reduction effect

[0006] "Method for desiliconization of blast furnace hot metal pretreatment (patent number; 02153413.6)", "a manufacturing method of hot metal desulfurization and low-silicon hot metal (patent number: 03802274.5)", "high chromium-containing molten iron silicon reduction process (patent number 200610028377.3)" , "Substantial desulfurization in front of molten iron furnace or simultaneous three desulfurization to completely liberate blast furnace and converter" (Patent No.: 200510071571.5), or use injection, oxygen blowing, filling of desiliconization materials in the furnace, or flow down the silicon outside the furnace, The biggest common point of these operation methods is only the oxidation and silicon reduction operation of molten iron, and does not discuss how to deal with the peroxidation of molten iron in essence. The molten iron after silicon reduction according to the above method is only used as the main material for steelmaking, and cannot be directly poured into products.