CN108862402B - Method for recycling iron resources in steel slag - Google Patents
Method for recycling iron resources in steel slag Download PDFInfo
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- CN108862402B CN108862402B CN201810997236.5A CN201810997236A CN108862402B CN 108862402 B CN108862402 B CN 108862402B CN 201810997236 A CN201810997236 A CN 201810997236A CN 108862402 B CN108862402 B CN 108862402B
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- steel slag
- iron
- steel
- slag
- oxidizing gas
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- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 114
- 239000010959 steel Substances 0.000 title claims abstract description 114
- 239000002893 slag Substances 0.000 title claims abstract description 104
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 title claims abstract description 85
- 229910052742 iron Inorganic materials 0.000 title claims abstract description 36
- 238000000034 method Methods 0.000 title claims abstract description 19
- 238000004064 recycling Methods 0.000 title claims description 11
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N iron oxide Inorganic materials [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 claims abstract description 36
- 238000007885 magnetic separation Methods 0.000 claims abstract description 16
- 230000001590 oxidative effect Effects 0.000 claims abstract description 16
- 238000001816 cooling Methods 0.000 claims abstract description 12
- 238000004321 preservation Methods 0.000 claims abstract description 11
- SZVJSHCCFOBDDC-UHFFFAOYSA-N iron(II,III) oxide Inorganic materials O=[Fe]O[Fe]O[Fe]=O SZVJSHCCFOBDDC-UHFFFAOYSA-N 0.000 claims abstract description 6
- 238000007664 blowing Methods 0.000 claims abstract description 5
- 239000007788 liquid Substances 0.000 claims abstract description 4
- 238000002844 melting Methods 0.000 claims abstract description 3
- 230000008018 melting Effects 0.000 claims abstract description 3
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 6
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 5
- 229910052681 coesite Inorganic materials 0.000 claims description 5
- 229910052593 corundum Inorganic materials 0.000 claims description 5
- 229910052906 cristobalite Inorganic materials 0.000 claims description 5
- 239000000377 silicon dioxide Substances 0.000 claims description 5
- 229910052682 stishovite Inorganic materials 0.000 claims description 5
- 229910052905 tridymite Inorganic materials 0.000 claims description 5
- 229910001845 yogo sapphire Inorganic materials 0.000 claims description 5
- 239000000126 substance Substances 0.000 claims description 2
- 239000002910 solid waste Substances 0.000 abstract description 5
- 238000004519 manufacturing process Methods 0.000 abstract description 3
- 238000007796 conventional method Methods 0.000 abstract description 2
- 239000000463 material Substances 0.000 abstract description 2
- 229910052596 spinel Inorganic materials 0.000 abstract description 2
- 239000011029 spinel Substances 0.000 abstract description 2
- 238000005516 engineering process Methods 0.000 description 4
- 238000011084 recovery Methods 0.000 description 4
- 238000001514 detection method Methods 0.000 description 3
- 238000011161 development Methods 0.000 description 3
- 238000001035 drying Methods 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- 239000002245 particle Substances 0.000 description 3
- 230000009467 reduction Effects 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- 229910001341 Crude steel Inorganic materials 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 238000004134 energy conservation Methods 0.000 description 2
- 229910052500 inorganic mineral Inorganic materials 0.000 description 2
- 229910052909 inorganic silicate Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 239000011707 mineral Substances 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000004568 cement Substances 0.000 description 1
- 238000002425 crystallisation Methods 0.000 description 1
- 230000008025 crystallization Effects 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 230000007717 exclusion Effects 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 239000002440 industrial waste Substances 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 238000005272 metallurgy Methods 0.000 description 1
- 239000010813 municipal solid waste Substances 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 238000001953 recrystallisation Methods 0.000 description 1
- 238000009270 solid waste treatment Methods 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
- C01G49/00—Compounds of iron
- C01G49/02—Oxides; Hydroxides
- C01G49/08—Ferroso-ferric oxide [Fe3O4]
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
- C01G49/00—Compounds of iron
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Manufacture And Refinement Of Metals (AREA)
- Carbon Steel Or Casting Steel Manufacturing (AREA)
Abstract
The invention provides a method for recovering iron resources in steel slag, which comprises the following steps: melting steel slag, and blowing adjustable oxidizing gas onto the liquid level of the steel slag to oxidize FeO in the steel slag; step two, cooling the reacted steel slag, and preserving heat after the temperature is stable; and step three, cooling the steel slag after heat preservation. After the steps, the finally generated MgFe2O4Spinel phase and Fe3O4All are the main iron-containing material phases in the steel slag utilized in the invention. Through the treatment steps provided by the invention, (1) the iron grade in the steel slag after magnetic separation is obviously improved, and the steel slag can be used as an iron ore resource for steel production; (2) compared with the conventional method for recovering and treating the steel slag iron resource, the method greatly improves the yield of iron in the steel slag; (3) obviously reduces the amount of steel slag after treatment and plays a role in reducing solid waste of the steel slag.
Description
Technical Field
The invention relates to the field of metallurgy and solid waste treatment, in particular to a method for recovering iron resources in steel slag, which is not specific to converter steel slag with certain fixed alkalinity, FeO content and specific heat preservation temperature.
Background
The steel industry in China has huge output, and as solid waste discharged in the steel production process, about 120kg of steel slag is discharged per ton of steel produced. According to the statistical data of steel in the world, the total yield of crude steel in the whole country in 2017 is 8.32 hundred million tons, and the problem of steel slag treatment is brought along with the back of huge crude steel data. As many steel mills in China adopt simpler 'crushing-screening-magnetic separation', only the metal iron particles in the steel mills are recovered, and the residual steel slag tailings are mostly piled up or backfilled, the method not only occupies land and pollutes the environment, but also causes serious waste of resources. The total utilization level of steel slag in China is not high, the comprehensive utilization rate is only about 20 percent, and the utilization level is far lower than that of steel slag in developed countries (for example, steel slag in America, Japan and Germany reaches the exclusion balance). At present, all countries in the world evaluate and develop solid wastes, the world iron and steel association brings the recycling and treatment stages of steel slag into life cycle evaluation (from raw material collection stage to life end stage), and governments also put the comprehensive utilization of solid wastes into an important agenda, continuously improve various regulations and provide related encouragement and preferential policies. In China, energy conservation and emission reduction of the steel industry become the key points of transformation of the current steel industry. The development planning of the state of thirteen five clearly indicates that the development of the resource recycling industry is accelerated, the comprehensive utilization of mineral resources is enhanced, the industrial waste recycling is encouraged, a renewable resource recycling system and a garbage classification recycling system are perfected, and the resource recycling industrialization is promoted. The method has the advantages of developing and applying sources, recycling, remanufacturing, zero emission and industrial linking technologies, and popularizing the circular economy typical mode. With the development of steel slag treatment and utilization technology, various large iron and steel enterprises can fully utilize beneficial components in slag and recover iron-containing resources, and simultaneously apply tailings in different ways such as steel slag cement, metallurgical raw materials, concrete and the like. The comprehensive utilization of the steel slag becomes one of the important subjects of steel enterprises and even the whole society, and the finding of a proper processing technology to treat the steel slag and the realization of energy conservation, consumption reduction, cost reduction and efficiency improvement is an important technical problem which needs to be solved urgently by the steel enterprises.
The steel slag not only contains metallic iron, but also has FeO content as high as 20-30%. According to investigation, at present, the recovery of iron resources in steel slag is mainly focused on a mode of partially reducing metallic iron or iron oxide, the recovery efficiency is low, at present, a new process for separating and recovering valuable metal elements is mainly developed, and the metal resources are selectively enriched and separated through a recrystallization technology.
Disclosure of Invention
The invention aims to solve the problem of improving the recovery rate of iron resources in the converter steel slag.
The invention provides a method for recovering iron resources in steel slag, which is characterized by comprising the following steps of:
melting steel slag, blowing adjustable oxidizing gas onto the liquid level of the steel slag to oxidize FeO in the steel slag, wherein the oxidizing gas is excessive so that the steel slag is fully oxidized, and the principle of the reaction of the molten steel slag and the oxidizing gas is as follows:
FeO(l)+Oxidizing Gas→Fe3O4
and step two, carrying out cooling operation on the reacted steel slag, and carrying out heat preservation after the temperature is stable, wherein the temperature is selected to be 1200-1400 ℃, and the heat preservation time t is more than or equal to 3 h.
Cooling the steel slag after heat preservation, wherein the cooling speed of the steel slag is 100-300 ℃/min;
and step four, crushing and magnetically separating the cooled steel slag, wherein the crushed steel slag is below 200 meshes, and the magnetic separation method is low-intensity magnetic separation.
The steel slag sample comprises the following chemical components: 36-10% of CaO and 20-24% of SiO220-24% of FeO, 6-10% of MgO, 5% of MnO and 5% of Al2O3。
The scheme disclosed by the invention has the following advantages:
1. the method for recovering iron resources in steel slag provided by the invention has the following main crystallization process of iron-containing phase in the steel slag:
after the steel slag is melted in the step I, elements in the steel slag exist in an ion form in the molten state, and then the steel slag is blown to the liquid surface of the molten steel slag by adopting the adjustable oxidizing gas to oxidize FeO in the steel slag, so that the FeO in the steel slag stably exists in a phase of Fe at high temperature after reacting with the oxidizing gas3O4；
Then, as the second step is carried out, the temperature is gradually reduced, and Ca in the steel slag is reduced2SiO4The phase begins to precipitate first, then part of free MgO begins to precipitate, and the solution enters Ca at a certain temperature2SiO4Formation of Ca in3MgSiO8When the temperature reaches the holding temperature set by the invention, MgO is precipitated from the phase and combined with the iron oxide to form stable MgFe2O4A spinel phase.
Finally, MgFe is produced2O4Tip crystalStone phase and Fe3O4All are the main iron-containing material phases in the steel slag utilized in the invention.
2. According to the method for recycling the iron resource in the steel slag, the iron grade in the steel slag after magnetic separation is obviously improved, and the steel slag can be used as an iron ore resource for steel production; compared with the conventional method for recovering and treating the steel slag iron resource, the method greatly improves the yield of iron in the steel slag; obviously reduces the amount of steel slag after treatment and plays a role in reducing solid waste of the steel slag.
Detailed Description
The technical solutions of the present invention will be described clearly and completely below, and it should be apparent that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In addition, the technical features involved in the different embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.
Example 1
In this example, 20g of steel slag was selected. The contents of the components in the steel slag are shown in table 1. Wherein, CaO accounts for 8 g; SiO 22Is 4 g; FeO 4 g; MgO accounts for 2 g; MnO is 1 g; al (Al)2O3Is 1 g.
After 20g of steel slag is kept to be molten at 1600 ℃, water vapor is blown to the surface of the molten steel slag to serve as oxidizing gas for more than 2 hours, and FeO in the steel slag is oxidized; reducing the temperature of the steel slag after reaction to 1200 ℃, and preserving the heat for 3 hours; the steel slag after heat preservation is rapidly cooled, and the cooling speed of the steel slag is 100 ℃/min; and crushing the cooled steel slag to obtain steel slag with granularity below 200 meshes and magnetic field intensity of 200mT for magnetic separation. Drying the magnetic separation product to obtain a magnetic phase 6.721g, and determining to recover Fe mainly as Fe in the magnetic phase through XRF and XRD detection3O4And MgFe2O4The iron grade was 24.5%, and the yield of iron element was 94.09%.
In this embodiment, the specific parameters are defined as follows:
1. iron grade: total iron content in the mineral, i.e. TFe.
2. The yield of iron element is as follows:
wherein M isGeneral assembly: the mass of the slag before magnetic separation; mMagnetic field: the quality of the slag after magnetic separation; TFeGeneral assembly: the iron content in the slag before magnetic separation; TFeMagnetic field: the iron content in the slag after magnetic separation.
Example 2
Example 2 is essentially the same as example 1, except that:
CaO content 36%, SiO224% of FeO, 25% of MgO, 5% of MnO, Al2O3Taking 20g of steel slag with the content of 5%, keeping the steel slag molten at 1600 ℃, blowing water vapor to the surface of the molten steel slag to serve as oxidizing gas for more than 2 hours, and oxidizing FeO in the steel slag; reducing the temperature of the steel slag after reaction to 1300 ℃, and preserving the temperature for 4 hours; the steel slag after heat preservation is rapidly cooled, and the cooling speed of the steel slag is 200 ℃/min; and crushing the cooled steel slag to obtain steel slag with granularity below 200 meshes and magnetic field intensity of 200mT for magnetic separation. Drying the magnetic separation product to obtain 5.990g of a magnetic phase, and determining that Fe in the recovered magnetic phase is mainly Fe through XRF and XRD detection3O4And MgFe2O4The iron grade is 25.9 percent, and the yield of the iron element is 88.65 percent.
Example 3
Example 3 is essentially the same as example 1, except that:
CaO content 38%, SiO222% of FeO, 22% of MgO, 5% of MnO, Al2O3Taking 20g of steel slag with the content of 5%, keeping the steel slag molten at 1600 ℃, blowing water vapor to the surface of the molten steel slag to serve as oxidizing gas for more than 2 hours, and oxidizing FeO in the steel slag; reducing the temperature of the steel slag after reaction to 1400 ℃, and preserving the temperature for 5 hours; the steel slag after heat preservation is rapidly cooled, and the cooling speed of the steel slag is 300 ℃/min; cooling the steel slagCrushing to obtain particles with particle size below 200 meshes and magnetic field strength of 200 mT. Drying the magnetic separation product to obtain 5.639g of a magnetic phase, and determining that Fe in the recovered magnetic phase is mainly Fe through XRF and XRD detection3O4And MgFe2O4The iron grade was 26.9%, and the yield of iron element was 86.68%.
Comparative example
In the comparative example, a common recovery method in the prior art is adopted, the grade of the recovered iron is 23%, and the yield of the iron element is 70%.
It can be seen that both the iron grade and the iron element yield are lower than those obtained by the methods of examples 1-3.
TABLE 1 Steel slag with contents of each component
| CaO/％ | SiO2/％ | FeO/％ | MgO/％ | MnO/％ | Al2O3/％ | |
| Example 1 | 40 | 20 | 20 | 10 | 5 | 5 |
| Example 2 | 36 | 24 | 24 | 6 | 5 | 5 |
| Example 3 | 38 | 22 | 22 | 8 | 5 | 5 |
It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications therefrom are within the scope of the invention.
Claims (2)
1. A method for recycling iron resources in steel slag is characterized by comprising the following steps:
melting steel slag, and blowing adjustable oxidizing gas onto the liquid level of the steel slag to oxidize FeO in the steel slag;
step two, cooling the reacted steel slag, and preserving heat after the temperature is stable;
step three, cooling the steel slag after heat preservation;
step four, crushing and magnetically separating the cooled steel slag;
selecting the heat preservation temperature at 1400 ℃;
step two, the heat preservation time is between 3h and 5 h;
in the third step, the cooling speed of the steel slag is 100-300 ℃/min;
in the fourth step, the steel slag is crushed to be below 200 meshes, and the magnetic separation method is low-intensity magnetic separation;
the steel slag sample comprises the following chemical components: 36-40% of CaO and 20-24% of SiO220-24% of FeO, 6-10% of MgO, 5% of MnO and 5% of Al2O3。
2. The method of claim 1, wherein the oxidizing gas is in excess in the first step, so that the steel slag is fully oxidized;
the principle of the reaction of the molten steel slag and the oxidizing gas is as follows:
FeO(l)+Oxidizing Gas→Fe3O4。
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| Application Number | Priority Date | Filing Date | Title |
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| CN201810997236.5A CN108862402B (en) | 2018-08-29 | 2018-08-29 | Method for recycling iron resources in steel slag |
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| CN201810997236.5A CN108862402B (en) | 2018-08-29 | 2018-08-29 | Method for recycling iron resources in steel slag |
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| CN108862402A CN108862402A (en) | 2018-11-23 |
| CN108862402B true CN108862402B (en) | 2020-09-04 |
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Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106191344A (en) * | 2016-07-18 | 2016-12-07 | 东北大学 | A kind of slag melting and reducing that mixes produces the method with modifier treatment |
| CN108070687A (en) * | 2017-12-01 | 2018-05-25 | 北方民族大学 | A kind of converter slag phase oxidative method for modifying |
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2018
- 2018-08-29 CN CN201810997236.5A patent/CN108862402B/en not_active Expired - Fee Related
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106191344A (en) * | 2016-07-18 | 2016-12-07 | 东北大学 | A kind of slag melting and reducing that mixes produces the method with modifier treatment |
| CN108070687A (en) * | 2017-12-01 | 2018-05-25 | 北方民族大学 | A kind of converter slag phase oxidative method for modifying |
Non-Patent Citations (2)
| Title |
|---|
| Formation of spinel phase in oxide bof slag under different cooling conditions;Liang jiang et al.;《Steel research international》;20171231;第88卷(第11期);1700066 * |
| 改性转炉渣中MgF2O4的形成与磁选提铁;薛鹏等;《钢铁》;20170731;第52卷(第7期);第104-110页 * |
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| CN108862402A (en) | 2018-11-23 |
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