Reduced iron powder production process for improving performance of reduced iron powder

Reduced iron powder production process for improving performance of reduced iron powder

  • CN 107,008,914 B
  • Filed: 04/06/2017
  • Issued: 09/07/2021
  • Est. Priority Date: 04/06/2017
  • Status: Active Grant
First Claim
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1. A production process of reduced iron powder for improving the performance of the reduced iron powder is characterized by comprising the following steps:

  • uniformly mixing iron-containing powder, coke powder and a flux, adding the mixture into a kiln for primary reduction, wherein the temperature of the primary reduction is controlled to be 1160 +/-10 ℃

    , and obtaining sponge iron raw powder after the primary reduction is finished;

    adding sponge iron raw powder into a fine reduction furnace, and adopting a furnace containing H2The reducing gas is finely reduced to obtain reduced iron, wherein the TFe of the sponge iron raw powder is more than or equal to 97.2 percent, the C is less than or equal to 0.30 percent, and the normal reduction temperature of fine reduction is 940-950 ℃

    ;

    crushing the reduced iron, and batching to obtain reduced iron powder, wherein the mass ratio of the reduced iron powder to 200 meshes is controlled to be 48-54%;

    the reduced iron powder production process for improving the performance of the reduced iron powder;

    the iron-containing powder is also added with an additive, and the mass ratio of the iron-containing powder to the additive is 20;

    the additive comprises biomass powder, urea and plastic powder, wherein the mass percentages of the biomass powder, the urea and the plastic powder are as follows;

    biomass powder;

    80% and urea;

    10%, plastic powder;

    10 percent;

    the method comprises the following specific steps;

    s100, pretreating and uniformly mixing raw materialsFinely grinding the iron-containing powder until the mass percentage of the powder is 88-90% of-60 meshes, mixing the iron-containing powder, part of coke powder and a flux to obtain a mixture, and filling the raw material of the mixture into a SiC tank;

    s200, primary reduction of mixturePutting the canned mixture into a tunnel kiln, and controlling the temperature of a reduction zone as follows;

    reducing at 1160 ℃ and

    10 ℃

    to obtain sponge iron;

    s300, raw meal fine reductionAfter sponge iron is crushed, H-containing gas is firstly filled into a fine reduction furnace2Adding the sponge iron raw powder into a fine reduction furnace, wherein the charging indexes of the sponge iron raw powder are that TFe is more than or equal to 97.2 percent and C is less than or equal to 0.30 percent;

    the reduction zone temperature is;

    940-950 ℃

    ; and

    alsoPressure of raw gas>

    0.018Mpa, and obtaining pressed powder after reduction;

    s400, crushing and screening combined batchThe iron powder after crushing, screening and magnetic separation is classified according to different particle sizes, and the sizes of the classified screens are respectively 100 meshes, 150 meshes and 200 meshes;

    the method comprises the following steps of (1) batching the iron powder and mixing in a batching machine, wherein the granularity of the reduced iron powder after batching is as follows;

    +100 mesh;

    0.5-1%, 100 meshes to +150 meshes;

    25-30%, 200 mesh;

    48-54 percent of the total weight, and the balance of-150 meshes to +200 meshes;

    s100, the raw material pretreatment and the uniform mixing specifically comprise the following steps;

    sl10 pretreatment of raw materialsFirstly, drying the iron-containing powder at 500-600 ℃

    , and then carrying out ball milling on the dried iron-containing powder, wherein the mass percentage of-60 meshes of the iron-containing powder is 88-90%, and the mass percentage of-200 meshes of the iron-containing powder is 34-38%;

    screening out particles larger than 3mm in the coke powder and the flux by using a 3mm sieve;

    s120, uniformly mixing and canningMixing the iron-containing powder, part of the coke powder and the flux to obtain a mixture, filling the raw material of the mixture into a SiC tank, and covering the top of the mixture with the residual coke powder;

    the iron-containing powder, the coke powder and the flux are mixed according to the mass ratio of;

    (1.5-2.0);

    1;

    (1/8-1/6);

    s300, the specific steps of the raw starch fine reduction are as follows;

    s310, crushing and magnetic separationCrushing sponge iron to obtain sponge iron raw powder, wherein the granularity of the raw powder is more than or equal to 97 percent when the raw powder is 80 meshes;

    then, selecting particles with the particle size of 0-2mm by using a magnetic separator;

    s320, preparing reducing gasGasifying nitrogen in a gasifier before the nitrogen enters the cracking furnace, and filling ammonia gas in the cracking furnace to prepare H2And N2Mixing reducing gas;

    wherein the cracking temperature of the cracking furnace is 900-;

    0.25-0.60 MPa, the cracking gas pressure gauge pressure is;

    0.0175-0.023 MPa;

    s330, fine reduction, namely filling H into a fine reduction furnace2And N2Mixing the reducing gas, and pulverizing sponge ironAdding the sponge iron raw powder into a fine reduction furnace, wherein the charging indexes of the sponge iron raw powder are that TFe is more than or equal to 97.2 percent and C is less than or equal to 0.30 percent;

    wherein the temperature of a preheating zone in the fine reduction furnace is as follows;

    750-900 ℃

    , and the temperature of a reduction zone is as follows;

    940-950 ℃

    , and the temperature of the cooling zone is as follows;

    760 to 900 ℃

    ;

    pressure of reducing gas>

    0.018 MPa; and

    obtaining the pressed powder after the reduction is finished.

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