Method and vertical kiln for producing magnetic ferrous powder

Abstract

A method for producing magnetic ferrous refined powder and its apparatus are disclosed. The process is carried out by crushing, sieving, mixing, reducing by vertical kiln, magnetic polishing, ball grinding and magnetic selecting for twice. Raw material inlet is arrange at top of vertical kiln, feed section, reduction section and cooling section are placed in internal cavity successively, internal diameter of feed section is smaller than that of reduction section, which limits feeding speed and forms rest angle during process of drop of granular material, a space is formed between materials and internal wall of reduction section of vertical kiln, fuel coal is jetted into space to burn. It ensures reducer for reaction and makes full reaction with Fe2O3. It's fast and continuous.

Description

technical field [0001] The invention relates to a method for producing magnetic Fe 3 o 4 The production method and equipment of fine iron powder, particularly relate to a kind of will contain Fe 2 o 3 The iron ore is reduced to magnetite by vertical kiln and further magnetically separated to obtain magnetic iron concentrate powder and the vertical kiln. Background technique [0002] Magnetic iron concentrate refers to powdery Fe 3 o 4 . At present, the production method of magnetic iron concentrate is usually to obtain magnetite with magnetism by magnetic separation of magnetite, and magnetite can be reduced from iron ore such as hematite in a shaft kiln. At present, the technological process of producing magnetic iron concentrate powder by reducing iron ore such as hematite generally includes: crushing, screening, mixing, shaft kiln reduction, magnetic throwing, ball milling, and magnetic separation. The shaft kiln belongs to intermittent production. It is negative p...

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Problems solved by technology

There are following defects in this iron ore vertical kiln reduction method: 1, the qualified rate of products of the intermittent production mode of vertical kiln is not high, and production efficiency is low; However, the magnetic separation is only performed once, and the non-magnetic and magnetic substances produced after the ball milling are not separated, the processing volume is large, and the efficiency of the ball milling and magnetic separation is not high; the structure of the shaft kiln has the following defects: 1. Due to the feeding section and reduction The inner diameters of the cooling section and the cooling section are equal. After feeding, the inner cavity of the vertical kiln is basically filled with solid materials. There is not enough space in the inner cavity to accommodate the reducing gas, and a sufficient reducing environment is not formed in the vertical kiln, resulting in insufficient interaction between the reducing gas and the solid material. The contact opportunity can only be achieved by increasing the residence time of the reactants to achieve a complete reaction. Often there is insufficient iron ore reduction, and the reaction effect can only be guaranteed by one kiln method at a time; 2. The reduction reaction needs the participation of oxygen. The prior art is to use The inner cavity of the vertical kiln is in a negative pressure state and sucks air through the feed port to ensure that oxygen enters the reduction section continuously. The side effect is that oxygen will inevitably enter the cooling section. 3. Coal is usually used as both a reducing agent and a fuel, and they all enter from the upper end of the shaft kiln. There is no artificial distinction between the coals used for different purposes, and the temperature in the kiln is difficult to control. The temperature in the kiln is too high, and the Fe in the iron ore 2 o 3 Combined with silica to form iron silicate, which is not conducive to magnetic separation in subsequent processes

4. Due to the limited combustion space, the coal injection combustion method cannot be used, and only the intermittent production method of one-time feeding can be used

In summary, the existing iron ore vertical kiln reduction method for producing magnetic iron concentrate powder and the vertical kiln belong to intermittent production, the pass rate is generally only about 50%, the production efficiency is low, and it is impossible to realize industrialized continuous production. Improve

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