Search

CN-121972673-A - Method for preparing superfine iron powder by using pickling ferric oxide powder in steel mill

CN121972673ACN 121972673 ACN121972673 ACN 121972673ACN-121972673-A

Abstract

The invention belongs to the technical field of metallurgy, and provides a method for preparing superfine iron powder by using steel mill pickling ferric oxide powder, which fully utilizes the unique characteristics of fine granularity, high surface activation energy, low reduction temperature and 400-500 ℃ of furnace bottom generation temperature carried with waste heat of the steel mill pickling ferric oxide powder, combines the advantage of strong reducibility of plasma hydrogen, realizes waste heat recycling and low-temperature reduction, reduces the reduction temperature by 300-400 ℃ compared with the traditional hydrogen reduction process, obviously reduces energy consumption and has obvious energy-saving effect; the electromagnetic heating rotary kiln with the inner helical blades is adopted as a reduction device, the traditional push plate kiln and tunnel kiln are replaced, the boat pot is not required to hold materials, the contact area and the contact uniformity of plasma-state hydrogen and ferric oxide powder are greatly improved by matching with sonic stirring, the full reduction is ensured, and the defects that the boat pot is not permeable in hydrogen reduction and secondary reduction is required in the traditional process are effectively overcome.

Inventors

  • LI BAYU
  • Li Suixuan

Assignees

  • 石家庄岑顺磁业科技有限公司
  • 李绥暄

Dates

Publication Date
20260505
Application Date
20260209

Claims (10)

  1. 1. The method for preparing the superfine iron powder by using the pickling ferric oxide powder of the steel mill is characterized by comprising the following steps of: s01, selecting acid-washed iron oxide powder at the bottom of an acid regeneration spray roasting furnace of a steel mill as a raw material, and carrying out heat preservation and conveying of the acid-washed iron oxide powder to a reduction device; s02, heating the acid-washed ferric oxide powder to a reduction temperature through the reduction device, introducing plasma hydrogen into the reduction device to serve as a reducing agent, and completing a reduction reaction between the acid-washed ferric oxide powder and the plasma hydrogen under the stirring condition to generate iron powder; S03, sequentially carrying out cooling, magnetic separation purification and air flow classification treatment on the iron powder after the reduction reaction to obtain a superfine iron powder finished product; s04, conveying the incompletely reduced oxidized impurities separated in the magnetic separation and purification process back to the reduction device for reduction reaction again.
  2. 2. The method for preparing ultrafine iron powder by using the acid-washed iron oxide powder of steel mill as set forth in claim 1, wherein in step S01, the acid-washed iron oxide powder at the bottom of the regenerative spray roasting furnace is transported to the reduction apparatus by a heat-preserving transport apparatus; the heat preservation conveying device comprises a feeding device and a heat preservation layer arranged on the feeding device; The waste heat generated by the acid-washing ferric oxide powder at the bottom of the acid-regenerating spray roasting furnace is utilized to ensure that the temperature of the raw materials is not lower than 350 ℃ when the raw materials are conveyed to a reduction device.
  3. 3. The method for preparing superfine iron powder by utilizing the pickling ferric oxide powder of a steel mill according to claim 2, wherein the feeding device is a spiral feeding device, the conveying speed is 0.2-0.5 m/s, the heat preservation layer is a rock wool heat preservation layer, and the thickness is 60-100 mm.
  4. 4. The method for preparing superfine iron powder by utilizing the pickling ferric oxide powder of a steelworks according to claim 1, wherein in the step S02, the reduction device is an electromagnetic heating rotary kiln with inner spiral blades, the reduction temperature is 500-600 ℃, the reduction device is combined with raw material waste heat for supplementary heating, the plasma hydrogen is prepared by a plasma generator, and the inflow rate of the plasma hydrogen is 2-5 m3/h.
  5. 5. The method for preparing superfine iron powder by utilizing the pickling ferric oxide powder of a steel mill according to claim 4, wherein the stirring condition is realized by driving a material to flow through an inner spiral blade and matching with sound waves generated by a sound wave generator, the rotating speed of the reduction device is 2-4 r/min, and the residence time of the material in the reduction device is 1.5-3 h.
  6. 6. The method for preparing ultrafine iron powder by using the pickling iron oxide powder in a steel mill according to claim 5, wherein the pitch of the inner spiral blade is 200-300 mm, and the sound wave generator generates sound waves of 20-50 kHz.
  7. 7. The method for preparing superfine iron powder by utilizing the pickling ferric oxide powder of a steel mill according to claim 1, wherein in the step S03, the cooling is performed by adopting an air cooling mode, the magnetic separation and purification are performed by adopting a permanent magnet separator, the air classification is performed by adopting a horizontal air classifier, the classification air flow speed is 8-12 m/S, and the classification particle size is controlled to be 1-10 mu m.
  8. 8. The method for preparing superfine iron powder by utilizing the pickling ferric oxide powder of a steelworks according to claim 1, wherein in the step S03, the nitrogen gas inlet flow rate of a discharge hole is 1-3 m < 3 >/h, and the nitrogen gas inlet pressure is 0.1-0.2MPa when the finished product is packaged.
  9. 9. The method for preparing ultrafine iron powder from a steel mill pickled iron oxide powder as set forth in claim 1, wherein in step S04, the incompletely reduced oxidized impurities are fed back to the reduction unit through an inert feed passage.
  10. 10. The method for preparing ultrafine iron powder by pickling iron oxide powder in a steel mill according to claim 9, wherein the inert delivery channel is realized by introducing inert gas into the delivery channel.

Description

Method for preparing superfine iron powder by using pickling ferric oxide powder in steel mill Technical Field The invention belongs to the technical field of metallurgy, and particularly relates to a method for preparing superfine iron powder by using pickling iron oxide powder in a steel mill. Background The superfine iron powder is used as an important functional metal material, has broad application prospect in a plurality of high and new technical fields such as powder metallurgy, magnetic materials, superhard materials, catalysts, precision chemical industry and the like by virtue of the unique physical and chemical characteristics, and continuously increases the demand of the market for the superfine iron powder along with the rapid development of related industries and continuously increases the requirements for the preparation quality and the production efficiency of the superfine iron powder. At present, the industrial method for preparing the superfine iron powder mainly comprises a plurality of process routes such as a reduction method, an electrolytic method, an atomization method and the like, wherein the reduction method becomes one of the main methods for preparing the superfine iron powder at present due to the advantages of mature process, wide raw material sources, relatively controllable production cost and the like, and is widely applied to industrial production. However, the conventional process for preparing superfine iron powder by using a reduction method still has a plurality of technical defects to be solved, the specific process generally adopts hydrogen as a reducing agent, a push plate kiln or a tunnel kiln is adopted as a reduction device, in the reduction process, iron oxide powder is required to be filled into a boat bowl and then is fed into the kiln for reduction reaction, and in order to meet the quality requirement of superfine iron powder, secondary reduction treatment and even tertiary reduction treatment are required to be carried out. And the granularity of the produced superfine iron powder with better quality is usually 500 meshes, and the purity is usually about 97 percent. The defects of the traditional process are mainly characterized in that on one hand, the temperature required by the hydrogen reduction reaction is higher and is usually controlled to be more than 900 ℃, the energy consumption in the production process is greatly increased due to the excessively high reaction temperature, the production cost is improved, meanwhile, the traditional process is not in line with the current industry development trend of energy conservation and environmental protection, and on the other hand, the iron oxide powder is contained in a boat pot, hydrogen is difficult to effectively penetrate into the material in the reduction process, only the superficial layer on the surface of the material can be subjected to the reduction reaction, an effective reduction atmosphere cannot be formed in the deep part of the material, the reduction reaction is insufficient, and the reduction efficiency is low. In order to make up for the defect, the prior art needs to crush the primary reduction product under the protection of nitrogen and then carry out secondary reduction, thereby not only increasing the process steps and making the whole preparation process more complex, but also further increasing the production energy consumption and the production cost and limiting the large-scale and efficient development of the superfine iron powder industry. Disclosure of Invention The invention provides a method for preparing superfine iron powder by using pickling ferric oxide powder in a steel mill, which aims to solve the technical problems described in the background art. In order to achieve the aim, the technical scheme adopted by the invention is that the method for preparing superfine iron powder by utilizing the pickling ferric oxide powder of a steelworks comprises the following steps: s01, selecting acid-washed iron oxide powder at the bottom of an acid regeneration spray roasting furnace of a steel mill as a raw material, and carrying out heat preservation and conveying of the acid-washed iron oxide powder to a reduction device; s02, heating the acid-washed ferric oxide powder to a reduction temperature through the reduction device, introducing plasma hydrogen into the reduction device to serve as a reducing agent, and completing a reduction reaction between the acid-washed ferric oxide powder and the plasma hydrogen under the stirring condition to generate iron powder; S03, sequentially carrying out cooling, magnetic separation purification and air flow classification treatment on the iron powder after the reduction reaction to obtain a superfine iron powder finished product; s04, conveying the incompletely reduced oxidized impurities separated in the magnetic separation and purification process back to the reduction device for reduction reaction again. In a possible implementation