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Method for preparing chromium-containing iron powder by direct reduction of calcium-free chromium slag

A technology of calcium-chromium-free slag and ferrochromium powder, applied in the direction of improving process efficiency, can solve the problems of high energy consumption, serious secondary pollution, low degree of resource utilization, etc., and achieves high recovery rate, reduced energy consumption, The effect of increasing the degree of resource utilization

Active Publication Date: 2012-11-28
HUBEI ZHENHUA CHEMICAL CO LTD +1
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0009] The purpose of the present invention is to overcome many problems such as low degree of resource utilization, serious secondary pollution, and high energy consumption in the prior art of calcium-free chromium slag treatment technology, and to provide a calcium-free chromium slag prepared by direct reduction to contain chromium The method of iron powder, the present invention uses calcium-free chromium slag as the main raw material, adds suitable reducing agent and flux, adopts direct reduction roasting-high-efficiency magnetic separation separation process to prepare reduced chromium-containing iron powder, and the prepared reduced product contains chromium, The sum of iron grades reaches over 80%, and the recovery rates of chromium and iron reach over 78% respectively

Method used

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  • Method for preparing chromium-containing iron powder by direct reduction of calcium-free chromium slag
  • Method for preparing chromium-containing iron powder by direct reduction of calcium-free chromium slag
  • Method for preparing chromium-containing iron powder by direct reduction of calcium-free chromium slag

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Embodiment 1

[0032] A method of preparing chromium-containing iron powder through direct reduction of calcium-free chromium slag in this embodiment, its process flow chart is as follows figure 1 As shown, the specific steps are as follows:

[0033] (1) Ingredients: mix calcium-chromium-free slag with reducing agent and flux, take 100 g calcium-chromium-free slag in the present embodiment, take 30 g anthracite coal powder as reducing agent, adopt X-ray fluorescence spectrometer and chemical analysis method to the above-mentioned The raw materials were analyzed. The physical and chemical indicators of calcium-free chromium slag and anthracite coal are shown in Table 1 and Table 2. X-ray diffraction analysis of calcium-free chromium slag shows that the minerals mainly include iron chromate, magnetite, forsterite, magnesium-iron Composition of olivine and silicate, from the chemical and phase analysis of calcium-free chromium slag, it can be seen that chromium slag mainly contains three eleme...

Embodiment 2

[0054] A kind of calcium-free chromium slag of the present embodiment prepares the method for chromium-containing iron powder through direct reduction, basically with embodiment 1, and the process parameter of its concrete steps is:

[0055] (1) Ingredients: Mix 100 g of calcium-free chromium slag with reducing agent and flux, wherein the flux is 9 g of alumina and 3 g of calcium fluoride, and the reducing agent is 30 g of anthracite coal powder. The quaternary alkalinity of the mixture is m(MgO+CaO) / m(SiO 2 +Al 2 o 3 )=0.9;

[0056] (2) Agglomeration: press the mixture in step (1) into cakes or pellets to obtain agglomerates;

[0057] (3) Reduction roasting: roast the blocks in step (2) in a reducing atmosphere, the reduction temperature is 1300 °C, and the time is 80 min;

[0058] (4) Crushing and fine grinding: crush the roasted block in step (3) and finely grind it to 80 meshes;

[0059] (5) Magnetic separation: The finely ground powder in step (4) was subjected to ma...

Embodiment 3

[0063] A kind of calcium-free chromium slag of the present embodiment prepares the method for chromium-containing iron powder through direct reduction, basically with embodiment 1, and the process parameter of its concrete steps is:

[0064] (1) Ingredients: Mix 100 g of calcium-free chromium slag with reducing agent and flux, wherein the flux is 1 g of alumina and 3 g of calcium fluoride, and the reducing agent is 30 g of anthracite coal powder. The quaternary alkalinity of the mixture is m(MgO+CaO) / m(SiO 2 +Al 2 o 3 )=1.3;

[0065] (2) Agglomeration: press the mixture in step (1) into cakes or pellets to obtain agglomerates;

[0066] (3) Reduction roasting: roast the blocks in step (2) in a reducing atmosphere, the reduction temperature is 1300 °C, and the time is 50 min;

[0067] (4) Crushing and fine grinding: crush the roasted block in step (3) and finely grind it to 120 mesh;

[0068] (5) Magnetic separation: The finely ground powder in step (4) was subjected to mag...

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Abstract

The invention discloses a method for preparing chromium-containing iron powder by direct reduction of calcium-free chromium slag, which belongs to the technical field of comprehensive utilization of chromium slag. The method comprises the following steps of: firstly, material preparation, wherein the calcium-free chromium slag is mixed with a reducing agent and fluxing agents comprising alumina, and the four-element alkalinity m(MgO+CaO) / m(SiO2+Al2O3) of the mixed material is equal to 0.9 to 1.3; secondly, agglomeration, wherein the mixed material is pressed or pelletized to obtain agglomerates; thirdly, reduction roasting, wherein the agglomerates are roasted in reducing atmosphere at a reduction temperature of 1,250 to 1,350 DEG C for 30 to 240 minutes; fourthly, crushing and fine grinding, wherein the roasted agglomerates are crushed and ground to be fine; and fifthly, magnetic separation, wherein the finely ground powder is subjected to magnetic separation at magnetic induction intensity of 100 to 200 mT, thereby separating the chromium-containing iron powder. According to the method, the calcium-free chromium slag is completely detoxified and fully recycled, the grade sum of calcium and iron in the prepared chromium-containing iron powder is over 80 percent, the chromium recovery rate and the iron recovery rate are respectively over 78 percent, and the method is low in energy consumption and free from secondary pollution.

Description

technical field [0001] The invention relates to the technical field of comprehensive utilization of chromium slag, and more specifically relates to a method for preparing chromium-containing iron powder through direct reduction of calcium-free chromium slag. Background technique [0002] Chromium salt is one of the main series of inorganic chemical products in my country. It is widely used in industries such as metallurgy, tanning, pigments, dyes, spices, metal surface treatment, wood preservation, and military industry. It is listed as the eight most competitive resources. One of the raw material products, the main products of chromium salt are sodium dichromate and chromic anhydride. [0003] The traditional production method of chromium salt is the calcium roasting process. Due to the use of calcium fillers such as dolomite, marble or quicklime, the amount of slag discharge is large (about 1.5~2.5 tons of slag based on the product of sodium chromate), and it contains a lar...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22B7/04
CPCY02P10/20
Inventor 蔡再华龙红明柯愈胜孟庆民石大学王平程西川王阿朋王学军赵刚
Owner HUBEI ZHENHUA CHEMICAL CO LTD
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