Molten iron lime-based KR efficient desulfurizer and preparation method thereof

Abstract

The invention relates to a molten iron lime-based KR efficient desulfurizer and a preparation method thereof. The desulfurizer comprises the following components in percentage by mass: 70-85% of lime particles and 15-30% of an additive, the lime particles comprise active lime particles and passivated lime particles; the additive comprises, by mass, 37%-63% of sintered calcium aluminate, 6%-13% of used magnesia carbon brick particles, 15%-30% of industrial sodium carbonate, 6%-13% of fluorite and 10%-20% of silicon-aluminum-calcium-carbon alloy. The desulfurizer prepared by the invention has the advantages of high desulfurization efficiency, large sulfur capacity, strong deliquescence resistance, small environmental pollution, simple preparation, low cost and the like.

Description

technical field [0001] The invention relates to the field of iron and steel smelting, in particular to a hot metal lime-based KR high-efficiency desulfurizer. Background technique [0002] The molten iron KR mechanical stirring desulfurization process uses the rectangular or inverted right-angled trapezoidal blades immersed in the molten iron to rotate and stir with a single-layer criss-cross arrangement of agitators, so that the lime desulfurizer added on the molten iron surface is circulated into the molten iron, and the desulfurization agent in the molten iron is realized. The continuous dispersion and interfacial desulfurization reaction can achieve the purpose of stable and deep desulfurization of molten iron. Therefore, it has superior kinetic conditions for desulfurization reaction and low cost of desulfurization agent consumption, and has become the preferred process for deep desulfurization of molten iron. At present, the commonly used desulfurizer for KR stirring d...

AI Technical Summary

Problems solved by technology

However, the desulfurizer is simply mixed with lime and aluminum slag and added to molten iron for desulfurization, which has several disadvantages: 1) under this ratio, the surface of lime particles is easy to form aluminosilicate with high melting point, which reduces its surface activity, and then reduces its 2) After lime and aluminum slag are mixed, the contact area between aluminum slag and molten iron is small, and the deoxidation effect is low; 3) Due to the different densities of aluminum slag and lime, it is difficult to ensure the desulfurization effect of the composite desulfurizer after the two are mechanically mixed. Uniformity

It can be seen that the high proportion of aluminum slag and low proportion of lime in the desulfurization agent of this composite structure will lead to high consumption of desulfurization agent and large amount of desulfurization slag, which is not conducive to the reduction of desulfurization temperature drop and slag removal iron loss, which will inevitably lead to desulfurization production costs. At the same time, the particle size of the desulfurization agent is too large, reaching 2-4mm, which will lead to difficulty in stirring and entrainment mixing of the desulfurization agent KR, and poor fluid dynamic conditions of the desulfurization reaction, further deteriorating the progress of the desulfurization reaction; in addition, the molten aluminum in the induction furnace It is difficult to ensure the uniformity of aluminum slag coating on the surface of lime particles by adding slag to the granulated lime particles and stirring and mixing the surface of the lime particles, especially when there is peeling along the bonding interface of the aluminum slag layer during the crushing process after solidification, resulting in Composite structure desulfurizer granular aluminum slag layer is not completely coated, it is difficult to completely overcome the shortcomings of simple mixed desulfurizers with aluminum slag and lime

[0006] For example, the Chinese invention patent with the publication number CN111979376A discloses a lime-based molten iron desulfurizer and its preparation method, which reduces the oxygen level of molten iron through the deoxidation of molten iron of metal aluminum and metal silicon, improves the thermodynamic conditions of the desulfurization reaction of calcium oxide in molten iron, and achieves a low melting point. The formation of calcium aluminate phase promotes slag on the lime surface, realizes the non-fluorination of desulfurization agent, and improves the mass transfer process of lime desulfurization reaction; through high-temperature decomposition of carbonate and degassing, it strengthens the stirring and mixing of molten iron desulfurization , to improve the kinetic conditions of the desulfurization reaction, but the ratio of lime and additives in the desulfurizer has a large control range, resulting in poor stability of various functions. At the same time, Al in the additive 2 o 3 , MgO and SiO 2 The high total content of lime will inevitably increase the temperature drop of molten iron desulfurization and affect the thermodynamic conditions of molten iron desulfurization reaction. In addition, the problem of moisture in the highly active lime has not been fully considered to improve measures