A method for resource-based treatment of iron and steel slag

Abstract

This invention relates to the field of pyrometallurgical technology, and in particular to a method for the resource-based treatment of iron and steel slag. The invention involves blowing oxygen-containing gas into molten iron and steel slag to oxidize free iron, obtaining oxidized molten iron and steel slag; mixing the oxidized molten iron and steel slag with silica-containing powder to undergo a silicification reaction, obtaining silicified molten iron and steel slag; and shaping the silicified molten iron and steel slag to obtain building materials. The method provided by this invention achieves complete resource utilization of iron and steel slag, eliminating the need for water quenching of the molten iron and steel slag, saving water resources, reducing liquid, gas, and solid pollution sources, and, more importantly, recovering and utilizing thermal energy, thus reducing carbon emissions and protecting the environment. Furthermore, the resulting product can be directly used as a building material, reducing the amount of natural stone and gravel required.

Description

Technical Field

[0001] This invention relates to the field of pyrometallurgical technology, and in particular to a method for the resource-based treatment of iron and steel slag. Background Technology

[0002] Iron and steel slag is a solid waste emitted by equipment such as converters and electric furnaces during the iron and steel metallurgical process. The amount emitted is about 15%-20% of crude iron and steel. Its main components are oxides of metals such as calcium, magnesium, silicon, iron, aluminum, and manganese. The mineral phases of the slag are dicalcium silicate, tricalcium silicate, calcium magnesium olivine, and metal oxide phases, as well as a small amount of free metallic iron and calcium oxide.

[0003] Currently, the main uses of steel slag are in the preparation of cement additives, roadbed fillers, wastewater adsorbents, and steel slag bricks. These methods not only consume small amounts of slag but also easily cause secondary pollution. For example, Baowu Steel Group, in collaboration with Wuhan University of Technology, developed a rapid mechanical stirring drum-type steel slag treatment process. This process utilizes rolling metal balls for crushing and rapid cooling, multi-point spray fine cooling, and online separation and sorting to rapidly cool molten steel slag from 1600℃ to below 100℃ and crush it into particles smaller than 15mm. Due to the high cooling rate and thorough crushing, the free calcium oxide content in the slag is effectively suppressed, dispersed, homogenized, and hydrated. Although the treated granular steel slag can be used for asphalt pavement, 3% calcium oxide residue remains, which may have adverse effects, resulting in low utilization. Another example is the process of grinding steel slag and then subjecting it to pressure carbonation to produce soluble calcium bicarbonate and calcium carbonate, but a large amount of refined residue still remains. Summary of the Invention

[0004] In view of this, the present invention provides a method for the resource-based treatment of steel slag, which realizes the complete resource utilization of steel slag and can also make full use of the heat of molten steel slag.

[0005] This invention provides a method for the resource-based treatment of iron and steel slag, comprising the following steps:

[0006] (1) Inject oxygen-containing gas into molten steel slag to oxidize free iron and obtain oxidized molten steel slag;

[0007] (2) The oxidized molten steel slag is mixed with silicon dioxide powder and subjected to a silicification reaction to obtain silicified molten steel slag;

[0008] (3) The silicified molten steel slag is shaped to obtain building materials.

[0009] Optionally, in step (1), the oxygen-containing gas is air, and the air is bubbled in at a rate of 1-4 m / s. 3 / (tons of steel slag·min), with a feed rate of 1-6m³. 3 / (tons of steel slag).

[0010] Optionally, the oxidation temperature of the free iron is 1700-1800℃.

[0011] Optionally, in step (2), the silica-containing powder has a mesh size of 20-50 mesh, and the silica content in the silica-containing powder is ≥60wt%.

[0012] Optionally, the silica-containing powder includes at least one of silica powder, fly ash, quartz sand, and non-toxic tailings.

[0013] Optionally, the stoichiometric ratio of silica to metal oxide in the mixture of the silica-containing powder and the oxidized molten steel slag is 1.2-1.5:1.

[0014] Optionally, the silanization reaction is carried out at a temperature of 1700-1800℃ for 1-2 hours.

[0015] Optionally, the forming method in step (3) is either casting or granulation; the casting method specifically involves injecting the silicified molten steel slag into a mold for pressure forming, wherein the pressure of the pressure forming is 13-20 MPa; the granulation method specifically involves injecting the silicified molten steel slag into a mold for extrusion granulation.

[0016] Optionally, after molding, the molded product undergoes heat recovery.

[0017] Optionally, after the heat is recovered, the residue and defective products generated in step (3) are returned to step (2) for recycling.

[0018] This invention provides a method for the resource-based treatment of steel slag. Oxygen-containing gas is bubbled into molten steel slag to oxidize free iron, resulting in oxidized molten steel slag. The oxidized molten steel slag is then mixed with silica-containing powder to undergo a silicification reaction, yielding silicified molten steel slag. The silicified molten steel slag is then shaped to obtain building materials, thus achieving full resource utilization of steel slag. This invention uses molten steel slag as raw material, eliminating the need to cool it into a solid state, and directly processes it, fully utilizing the heat generated during the smelting process. The raw material is oxidized, silicified, and shaped to directly obtain high-strength building materials, achieving complete utilization of steel slag. Furthermore, the method eliminates the need for water quenching of molten steel slag, saving water resources and reducing liquid, gas, and solid pollution sources, thus reducing carbon emissions and protecting the environment. The slag can also be directly used as a building material, reducing the amount of natural stone and gravel required. As can be seen from the examples, the parameters of the products obtained in this application are in line with or higher than the technical parameters of similar building materials. The prepared boards can be used to replace conventional building boards, and the obtained granular materials can be used to replace natural gravel and pebbles as building materials. Detailed Implementation

[0019] The present invention will be described below through specific embodiments. Those skilled in the art will understand that the specific embodiments described below are for illustrative purposes only and do not limit the scope of the invention in any way. Furthermore, in the following embodiments, unless otherwise specified, the reagents and equipment used are commercially available. If specific processing conditions and methods are not explicitly described in the following embodiments, conditions and methods known in the art can be used for processing.

[0020] This invention provides a method for the resource-based treatment of steelmaking slag, comprising the following steps:

[0021] (1) Inject oxygen-containing gas into molten steel slag to oxidize free iron and obtain oxidized molten steel slag;

[0022] (2) The oxidized molten steel slag is mixed with silicon dioxide powder and subjected to a silicification reaction to obtain silicified molten steel slag;

[0023] (3) The silicified molten steel slag is shaped to obtain building materials.

[0024] The resource utilization method for steel slag provided by this invention directly uses molten steel slag as raw material, oxidizes, silicifies, and shapes the raw material to directly obtain building materials with high strength, realizing the complete utilization of steel slag. It eliminates the need for water quenching of molten steel slag, saving water resources, reducing liquid, gas, and solid pollution sources, reducing carbon emissions and protecting the environment. Furthermore, it can be directly used as a building material, reducing the amount of natural stone and gravel used.

[0025] This invention first introduces oxygen-containing gas into molten steel slag to oxidize free iron, obtaining oxidized molten steel slag. The chemical reactions occurring during this process are shown in the following equation:

[0026] 4Fe + 3O₂ = 2Fe₂O₃

[0027] In this invention, the introduction of oxygen-containing gas can oxidize the free iron in the molten steel slag on the one hand, and the disturbance generated by the gas introduction is conducive to the full oxidation of the free iron on the other hand.

[0028] In some embodiments of the present invention, the oxygen-containing gas is air, and the air is bubbled in at a rate of 1-4 m / s. 3 / (tons of steel slag·min) (that is, 1-4m³ / min is required per ton of steel slag per minute) 3 (Air), specifically 1, 2, 2.5, 3 or 4 m 3 / (tons of steel slag·min); the air injection rate is 1-6m³. 3 / (tons of steelmaking slag), specifically 2, 4, or 6 m³ 3 / (tons of steel slag). In some embodiments of the present invention, air is used to oxidize the steel slag. Air is widely available and inexpensive, making it more suitable for industrial application. In actual operation, to ensure a more complete reaction, air can be introduced in batches, such as introducing air for 2 minutes every 20 minutes. Those skilled in the art can adjust this according to the specific circumstances. The aforementioned air introduction rate and amount ensure sufficient oxidation of the steel slag while minimizing heat loss.

[0029] In some embodiments of the present invention, the oxidation temperature of the free iron is 1700-1800℃, specifically 1700℃, 1750℃, or 1800℃. Below 1700℃, the viscosity of the molten steel slag is too high, resulting in poor fluidity and hindering air induction; above 1800℃, energy consumption is high. The aforementioned temperatures ensure smooth air induction while maintaining low energy consumption.

[0030] This invention does not specifically limit the source of the steel slag; any waste residue generated during steel smelting is acceptable. In this invention, molten steel slag is directly used as raw material for processing. This method can be directly integrated with the smelting process, avoiding energy loss caused by slag cooling.

[0031] After obtaining the oxidized molten steel slag, the present invention mixes the oxidized molten steel slag with silica-containing powder and carries out a silicification reaction to obtain silicified molten steel slag. The chemical reactions occurring in this process include the following:

[0032] Fe2O3+3SiO2=Fe2(SiO3)3MgO+SiO2=MgSiO3 CaO+SiO2=CaSiO3

[0033] MnO+SiO2=MnSiO3 Al2O3+3SiO2=Al2(SiO3)3

[0034] In some embodiments of the present invention, the silica-containing powder has a mesh size of 20-50 mesh, specifically 25 mesh, 35 mesh, or 45 mesh. A mesh size less than 20 mesh results in a slow silanization reaction and a long processing time; a mesh size greater than 50 mesh makes the silica-containing powder easily dispersed by hot air when added to steel slag. When the mesh size of the silica-containing powder is outside the above range, those skilled in the art can use conventional methods to grind it to the above range.

[0035] In some embodiments of the present invention, the silica-containing powder contains at least 60 wt% silica, specifically 60 wt%, 70 wt%, or 80 wt%. In some embodiments of the present invention, the silica-containing powder includes at least one of silica powder, fly ash, quartz sand, and non-toxic tailings. The present invention does not specifically limit the source of the silica-containing powder, as long as it meets the aforementioned content requirements. Furthermore, the silica-containing powder does not contain harmful metallic elements (such as mercury, lead, cadmium, thallium, and hexavalent chromium), nor does it contain harmful non-metallic elements (arsenic, fluorine, sulfur oxides, and chlorine compounds), and it does not contain radioactive substances.

[0036] In some embodiments of the present invention, the stoichiometric ratio of silica to metal oxide in the mixture of the silica-containing powder and the oxidized molten steel slag is 1.2-1.5:1, specifically 1.2:1, 1.3:1, or 1.4:1. A stoichiometric ratio within this range ensures that all metal oxidation undergoes silanization, generating highly stable silicates. Simultaneously, the resulting silanized molten steel slag exhibits high strength after molding. A ratio less than 1.2:1 results in incomplete metal silanization, while a ratio greater than 1.5:1 leads to vitrification and brittleness in the final product.

[0037] In some embodiments of the present invention, the temperature of the silanization reaction is 1700-1800℃, specifically 1700℃, 1750℃, or 1800℃. Temperatures below this range result in poor fluidity of the molten slag, which is detrimental to the silanization reaction; temperatures above this range result in excessive energy consumption.

[0038] In some embodiments of the present invention, the silanization reaction takes 1-2 hours, specifically 1 hour, 1.5 hours, or 2 hours. A reaction time shorter than this range results in incomplete silanization, while a reaction time longer results in high energy consumption. The aforementioned reaction time ensures both sufficient silanization and low energy consumption. Furthermore, using the aforementioned silica-containing powder and temperature conditions for the silanization reaction guarantees the shorter reaction time. Those skilled in the art can also monitor the silanization reaction products using a scanning electron microscope (such as the JSM-6390LV from Varian Scientific) to determine the reaction time, further reducing energy consumption.

[0039] In some embodiments of the present invention, steps (1) and (2) are carried out in a 20t / 12500KVA-EBT (industrial grade) electric arc steelmaking furnace with an arc temperature of 2000-6000℃. This furnace is a large-scale steelmaking furnace used for the production of high-quality carbon steel and alloy steel, with a steel output of 15 tons.

[0040] After obtaining the silicified molten steel slag, the present invention shapes the silicified molten steel slag to obtain building materials.

[0041] In some embodiments of the present invention, the molding method is a casting method or a granulation method. Specifically, the casting method involves injecting the silicified molten steel slag into a mold for pressure molding. The pressure of the pressure molding is 13-20 MPa, specifically 13 MPa, 15 MPa, 18 MPa, or 20 MPa. In an embodiment of the present invention, the pressure molding uses an LX series hot chamber die casting machine. The LX38T-LX400T has a clamping force of 308-4000 kN, an injection quantity of 7.2 kg, a system pressure of 105-140 Mbar, and the mold module has variable dimensions of 30-100 cm in length and 30-100 cm in width. In some embodiments of the present invention, the granulation method specifically involves injecting the silicified molten steel slag into a mold for extrusion granulation; in an embodiment of the present invention, the equipment used for extrusion granulation is an improved MGSL-30128 hot extrusion granulator (Guangzhou Putong), specifically improved by replacing some components with high-temperature alloys, with an experimental capacity of 500 kg / h, a granulation particle size of 10-20 mm, and the specific particle size data being measured by a laser particle size analyzer Rise-2008 (produced by Jinan Runzhi Technology Co., Ltd.).

[0042] In some embodiments of the present invention, after the silicified molten steel slag is formed, the formed product is subjected to heat recovery. The present invention does not have any special requirements for the heat recovery method. Any technology known in the art that can recover the heat during the product cooling process can be used. For example, the product is placed in a heat exchange device, and the heat released by the product is absorbed by the heat exchange medium.

[0043] In some embodiments of the present invention, after the silicified molten steel slag is formed, residues and defective products will be generated, and these residues and defective products will be returned to step (2) for recycling.

[0044] The method of the present invention can fully utilize the resources of steel slag, which has a low added value of metal elements.

[0045] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments. The embodiments of this application are only examples, and all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0046] The steel slag composition used in the following examples, by weight percentage, is as follows: CaO 46.3%, SiO2 33.7%, Fe2O3 (free iron converted to Fe2O3) 9.1%, MgO 8.3%, Al2O3 1.3%, TiO2 1.2%, MnO 0.1%.

[0047] Example 1

[0048] (1) Place 4 tons of molten steel slag in an electric arc furnace, set the furnace temperature to 1750℃, and spray water at a depth of 3m. 3 Air is bubbled in at a rate of / (tons of steel slag·min), with a bubbling volume of 6m³. 3 / ton of steel slag, to obtain oxidized molten steel slag;

[0049] (2) Add 35-mesh silica powder (of which the mass fraction of each component in the silica powder is 98.4% SiO2, 0.2% Fe2O3, 1.1% Al2O3, 0.2% Ca, and 0.1% Ti) to the oxidized molten steel slag according to the chemical equivalent ratio of silica to metal oxide in the final mixture of 1.5:1. Set the furnace temperature to 1750℃ and react for 1 hour to obtain silanized molten steel slag.

[0050] (3) The molten steel slag after siliconization is injected into the mold of the hot die casting machine and pressed under a pressure of 15MPa to form a building panel;

[0051] (4) The molded building panels are transferred to the heat recovery line for heat recovery and cooling, resulting in a panel with an area of ​​1m². 2 Building panels with a thickness of 3cm; the residue and defective products are returned to step (2) as raw materials for further processing.

[0052] Elemental analysis revealed that the obtained building materials contained 60% SiO2, 28% Ca, 5.3% Fe2O3, 1.2% Al2O3, 0.7% Ti, 0.05% MnO, and 4.7% MgO. X-ray diffraction (D8 Advance, Bruker, Switzerland) phase analysis showed that the metal oxides existed entirely in the form of silicates within the material.

[0053] Example 2

[0054] The building panels were prepared according to the method described in Example 1, except that the stoichiometric ratio of silica to total metal oxides in the mixture of the silica-containing powder and the oxidized molten steel slag was 1.1:1. X-ray diffraction (D8 Advance, Bruker, Switzerland) phase analysis showed that a small amount of metal oxides still existed in the material in the form of metal oxides.

[0055] Example 3

[0056] The building panels were prepared according to the method described in Example 1, except that the stoichiometric ratio of silica to metal oxide in the mixture of the silica-containing powder and the oxidized molten steel slag was 1.2:1. X-ray diffraction (D8 Advance, Bruker, Switzerland) phase analysis showed that the metal oxides existed entirely in the material as silicates.

[0057] Example 4

[0058] The building panels were prepared according to the method described in Example 1, except that the stoichiometric ratio of silica to metal oxide in the mixture of the silica-containing powder and the oxidized molten steel slag was 1.4:1. X-ray diffraction (D8 Advance, Bruker, Switzerland) phase analysis showed that the metal oxides existed entirely in the material as silicates.

[0059] Example 5

[0060] The building panels were prepared according to the method described in Example 1, except that the stoichiometric ratio of silica to metal oxide in the mixture of the silica-containing powder and the oxidized molten steel slag was 1.6:1. X-ray diffraction (D8 Advance, Bruker, Switzerland) phase analysis showed that the metal oxides existed entirely in the material as silicates.

[0061] Example 6

[0062] The building panels were prepared according to the method described in Example 1, except that the silica powder had a mesh size of 15. X-ray diffraction (D8 Advance, Bruker, Switzerland) phase analysis revealed that a small amount of metal oxides still existed in the material in the form of metal oxides.

[0063] Example 7

[0064] The building panels were prepared according to the method described in Example 1, except that the air inlet volume was 0.5 m³. 3 / (tons of steel slag). X-ray diffraction (D8Advance, Bruker, Switzerland) phase analysis showed that the metal oxides existed entirely in the form of silicates in the material, with some metals remaining unsiliconized and existing as free metals.

[0065] The compressive strength of the building materials obtained in Examples 1-7 was tested using a TYE-2000 compression testing machine (manufactured by Wuxi Jianyi Instrument Machinery Co., Ltd., testing machine class CLASS1, pressure 2000kN). The flexural strength of the obtained building materials was tested using a microcomputer-controlled electro-hydraulic servo universal testing machine (manufactured by Jinan Shidai Shijin Testing Machine Co., Ltd., pressure 2000kN). The strength was compared with that of cement board, ceramic board and cast iron board. The test results are shown in Table 1.

[0066] Table 1. Strength Comparison of Cement Board / Cast Iron Board / Ceramic Board / Modified Steel Slag Hot Casting Press Plate

[0067]

[0068] As shown in Table 1, the compressive strength of the building board prepared in this application is much higher than that of high-density cement board, ordinary ceramic board, and HT200 cast iron board, and the flexural strength is higher than that of cement board (higher than high-density cement board, medium-density cement board, and low-density cement board). When the stoichiometric ratio of silica to metal oxide in the mixture of silica-containing powder and oxidized molten steel slag is 1.2-1.5:1, the compressive strength of the building board gradually increases and the flexural strength gradually decreases with the increase of silicon content, but the overall compressive and flexural strengths remain high. When the stoichiometric ratio of silica to metal oxide is 1.1:1, a small amount of metal oxide cannot react completely, resulting in lower compressive and flexural strengths. When the stoichiometric ratio of silica to metal oxide is 1.6:1, although the metal oxides can be completely siliconized, the excessive silica leads to a decrease in both the compressive and flexural strengths of the resulting board. The silica-containing powder used in Example 6 has a slightly larger particle size, which means that the metal oxide cannot be completely silicified under the same conditions as in Example 1, resulting in varying degrees of reduction in compressive and flexural strength. In Example 7, due to the small amount of air blown in, not all iron was oxidized and therefore could not be silicified, existing as free iron, which reduced the compressive and flexural strength of the resulting board.

[0069] Example 8

[0070] Following steps (1) and (2) of the method in Example 1, silicified molten steel slag is prepared, and then the silicified molten steel slag is injected into the mold of a hot extrusion granulator for hot extrusion molding to obtain building pebbles with a diameter of 2 cm.

[0071] Example 9

[0072] The building pebbles were prepared according to the method of Example 8, except that the silica-containing powder added to the oxidized molten steel slag was 4 tons of power plant coal ash (SiO2 62.3%, Al2O3 27.4%, Fe2O3 3.5%, MgO 2.1%, CaO 4.7%).

[0073] Example 10

[0074] Following steps (1) and (2) of Example 2, silicified molten steel slag is prepared, and then the silicified molten steel slag is injected into the mold of a hot extrusion granulator for hot extrusion molding to obtain building pebbles with a diameter of 2 cm.

[0075] Example 11

[0076] Following steps (1) and (2) of Example 3, silicified molten steel slag is prepared, and then the silicified molten steel slag is injected into the mold of a hot extrusion granulator for hot extrusion molding to obtain building pebbles with a diameter of 2 cm.

[0077] Example 12

[0078] Following steps (1) and (2) of Example 4, silicified molten steel slag is prepared, and then the silicified molten steel slag is injected into the mold of a hot extrusion granulator for hot extrusion molding to obtain building pebbles with a diameter of 2 cm.

[0079] Example 13

[0080] Following steps (1) and (2) of Example 5, silicified molten steel slag is prepared, and then the silicified molten steel slag is injected into the mold of a hot extrusion granulator for hot extrusion molding to obtain building pebbles with a diameter of 2 cm.

[0081] Example 14

[0082] Following steps (1) and (2) of Example 6, silicified molten steel slag is prepared, and then the silicified molten steel slag is injected into the mold of a hot extrusion granulator for hot extrusion molding to obtain building pebbles with a diameter of 2 cm.

[0083] Example 15

[0084] Following steps (1) and (2) of Example 7, silicified molten steel slag is prepared, and then the silicified molten steel slag is injected into the mold of a hot extrusion granulator for hot extrusion molding to obtain building pebbles with a diameter of 2 cm.

[0085] The crushing value of the building pebbles prepared in Examples 8-15 was tested using a TYE-2000 pressure testing machine during the pressure process. The results are shown in Table 2.

[0086] Table 2. Indicators of Building Pebbles

[0087] Classification Crushing value GB / T14685 <10% (Class I, crushed stone) Example 8 7.4％ Example 9 8.0％ Example 10 8.5％ Example 11 8.1％ Example 12 7.8％ Example 13 8.7％ Example 14 8.8％ Example 15 9.0％

[0088] As shown in Table 2, the crushing values ​​of the building pebbles prepared in this application are all below 10%, which conforms to GB / T 14685. When the stoichiometric ratio of silica to total metal oxides in the mixture of the silica-containing powder and the oxidized molten steel slag is 1.2-1.5:1, the crushing value of the building pebbles gradually decreases with the increase of silicon content; while when the stoichiometric ratio of silica to total metal oxides is not within the above range, the crushing value of the building pebbles increases; in Examples 14 and 15, the crushing values ​​of the building pebbles are increased because some metals are not silicified.

[0089] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for the resource-based treatment of iron and steel slag, comprising the following steps: (1) Inject oxygen-containing gas into molten steel slag to oxidize free iron and obtain oxidized molten steel slag; (2) The oxidized molten steel slag is mixed with silicon dioxide powder and subjected to a silicification reaction to obtain silicified molten steel slag; (3) The silicified molten steel slag is shaped to obtain building materials; The silanization reaction is carried out at a temperature of 1700-1800℃ for 1-2 hours. The oxidation temperature of the free iron is 1700-1800℃; The stoichiometric ratio of silicon dioxide to metal oxide in the mixture of the silicon dioxide-containing powder and the oxidized molten steel slag is 1.2-1.5:

1.

2. The method for resource-based treatment of iron and steel slag according to claim 1, characterized in that, The oxygen-containing gas is air, and the air is bubbled in at a rate of 1-4 m / s. 3 / (tons of steel slag·min), with a feed rate of 1-6m³. 3 / (tons of steel slag).

3. The method for resource-based treatment of iron and steel slag according to claim 1, characterized in that, The silica-containing powder has a mesh size of 20-50 mesh, and the silica content in the silica-containing powder is ≥60wt%.

4. The method for resource-based treatment of iron and steel slag according to claim 3, characterized in that, The silica-containing powder includes at least one of silica powder, coal ash, quartz sand, and non-toxic tailings.

5. The method for resource-based treatment of iron and steel slag according to claim 1, characterized in that, The molding method is either casting or granulation. Specifically, the casting method involves injecting the silicified molten steel slag into a mold and then pressing it into shape, wherein the pressure of the pressing process is 13-20 MPa. The granulation method specifically involves injecting the silicified molten steel slag into a mold for extrusion granulation.

6. The method for resource-based treatment of iron and steel slag according to claim 1, characterized in that, After molding, the process also includes heat recovery of the molded product.

7. The method for resource-based treatment of iron and steel slag according to claim 1, characterized in that, It also includes returning the residue and defective products generated in step (3) to step (2) for recycling.

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