Protective method for hearth of vanadium titano-magnetite rotary hearth furnace used for coal-based direct reduction

Abstract

The invention discloses a protective method for the hearth of a rotary hearth furnace used for the direct reduction of the vanadium titano-magnetite. A common refractory material is laid on the lower part of the hearth of the rotary hearth furnace; titanium slag obtained from a directly reduced metallic pellet which is subjected the electric furnace fusion and separation is crushed to 2 to 10mm and is laid on the refractory material on the surface of the hearth of the rotary hearth furnace. A soft hearth working surface is formed by the titanium slag between the refractory material on the surface of the hearth of the rotary hearth furnace and the reduced furnace charge; and then the preset thickness of the soft hearth working surface is reduced due to the loss, and the crushed titanium slag can be loaded into the hearth of the rotary hearth furnace. As the titanium slag has a higher fusion point, the vanadium titano-magnetite can be prevented from being atomized and sticking to the hearth in the 1,300 to 1,400 DEG C direct reduction process during use. As the hearth is a loose and soft hearth, the vanadium titano-magnetite does not stick to the hearth even with expansion. Therefore, the method has the advantages of protecting the hearth and a screw discharger, protecting the titanium slag from being polluted by the refractory material, bringing about the cycle use of the titanium slag, reducing the furnace maintenance cost, and having obvious economic and social benefits.

Description

technical field [0001] The invention relates to a furnace protection method for a rotary hearth furnace used for coal-based direct reduction, in particular to a method for protecting the bottom of a rotary hearth furnace where vanadium-titanium magnetite is made of titanium slag obtained by melting in an electric furnace . Background technique [0002] The life of the rotary hearth furnace is an important indicator of the production of various metal elements in the direct reduction and comprehensive recovery of vanadium-titanium magnetite. According to our production practice, the cracking and damage of the bottom of the furnace are the decisive factors affecting the life of the rotary hearth furnace. [0003] When the rotary hearth furnace directly reduces ordinary iron ore, since only iron is recycled and other elements are not recovered, the rotary hearth furnace mainly reduces iron oxides to metallic iron. This reduced iron is also called sponge iron. In the next step, ...

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Problems solved by technology

Since the refractory material or sand at the bottom of the furnace will seriously pollute the titanium slag, it will significantly reduce the grade and quality of the titanium slag obtained after melting in the electric furnace

[0007] Chinese patent CN1242074 discloses a furnace start-up method for prolonging the service life of the blast furnace. Since blast furnace ironmaking is finally separated from slag and iron in a liquid state, and the melting point of blast furnace slag is low, the liquid metal and slag can easily damage the blast furnace lining refractory material.

Moreover, when the discharging screw at the outlet of the rotary hearth furnace discharges the reduced furnace charge, due to the existence of the furnace bottom adhesive, the discharging screw needs to be frequently repaired and the discharging screw cleaned, which constitutes a relatively difficult continuous and stable production. big impact and trouble

On the other hand, due to the fact that the furnace bottom refractory materials are mostly bonded into the melting electric furnace, the titanium slag is polluted, which affects the grade and quality of the titanium slag, so that the direct reduction of vanadium-titanium magnetite can not be obtained after melting in the electric furnace. Higher grade titanium slag is unfavorable to the utilization of titanium slag

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