Method for preparing high-lubricity continuous casting covering slag from magnesium reducing slag

Abstract

The invention provides a method for preparing high-lubricity continuous casting covering slag from magnesium reducing slag, and belongs to the technical field of metallurgy. The method provided by the invention comprises the following steps: uniformly mixing magnesium reducing slag, coal and a fluxing agent, pressing into blocks, and then roasting at high temperature; a product obtained through high-temperature roasting is crushed and then subjected to magnetic separation, a non-magnetic material obtained through magnetic separation is mixed with a binder, slurry making and granulation are conducted, and the high-lubricity continuous casting covering slag is obtained. The method provided by the invention not only has lower production cost, but also has remarkable environmental benefits, reduces the dependence on mineral resources, reduces the accumulation problem of industrial wastes, is widely applicable to the metallurgical industry, and has wide application prospects and important practical significance.

Description

Technical Field

[0001] The invention relates to the technical field of metallurgy, and in particular to a method for preparing high-lubricity continuous casting protection slag by utilizing magnesium reduction slag. Background Art

[0002] my country's magnesium enterprises mainly use silicon thermal reduction to smelt magnesium metal. This process produces a large amount of magnesium reduction slag during the production process. At present, the accumulated amount of magnesium reduction slag in China has exceeded 100 million tons. Due to the lack of effective treatment methods, these magnesium reduction slags not only lead to serious waste of resources, but also cause significant damage to the local ecological environment.

[0003] Magnesium reduction slag is an alkaline industrial waste. Random accumulation will not only cause dust pollution and form smog weather, but long-term exposure to this environment may also cause people to suffer from respiratory diseases and lung diseases. In addition, the large amount of magnesium reduction slag accumulation not only wastes land resources, but also easily leads to soil agglomeration and salinization, which harms the growth of crops. With the erosion of rainwater, some magnesium reduction slag will also enter rivers or seep into the ground, polluting water resources and further endangering human health. Therefore, how to realize the comprehensive utilization of magnesium reduction slag resources has become an important and urgent issue.

[0004] The resource utilization of magnesium reduction slag not only helps to reduce the environmental burden, but also has important significance for promoting the sustainable development of the metallurgical industry. At present, researchers have studied the resource utilization of magnesium reduction slag and achieved certain results, mainly focusing on the fields of building materials, fertilizers, industrial desulfurization and mine filling. However, most of these methods have the disadvantages of high processing cost, low utilization of magnesium reduction slag and strong substitutability, which makes it difficult to effectively solve the large-scale processing needs of magnesium reduction slag.

[0005] In the prior art, patent CN116219186A discloses a pre-melted slag and its preparation method and application, using CaF 2 、CaO、Al 2 O 3 , MgO and rare earth oxides to prepare pre-melted slag, which can reduce the rare earth, magnesium and SiO 2The reaction of impurities such as magnesium and rare earths can inhibit the burning of rare earths and magnesium during electroslag remelting. This patent takes into account the advantages of magnesium and rare earths and exerts synergistic benefits to improve the recovery rate of metals. Patent CN104058590B discloses a method for preparing foam glass from magnesium reduction slag, mixing magnesium reduction slag with silicate broken glass, adding foaming agent and flux, crushing and mixing in proportion, microwave heating and sintering to make foam glass. This patent takes into account the resource utilization and management of magnesium reduction slag, and combines it with broken glass to prepare a new type of material, aiming to create added value of new materials through waste slag resource utilization. However, the above patents still have problems such as high process complexity and difficulty in large-scale industrial application, resulting in the problem of magnesium reduction slag accumulation has not been fundamentally solved. With the gradual increase in the annual output of magnesium, the accumulation problem of magnesium reduction slag has become increasingly serious and has become an important factor restricting the development of the magnesium industry. Therefore, ensuring that magnesium reduction slag resources are fully utilized and realizing large-scale industrialization, harmless treatment and resource utilization of magnesium reduction slag has become an important focus of industry attention and an important direction for future research. Summary of the invention

[0006] In view of the low utilization rate and treatment difficulties of magnesium reduction slag at present, the object of the present invention is to provide a method for preparing high-lubricity continuous casting protection slag using magnesium reduction slag.

[0007] In order to achieve the above object, the present invention provides the following technical solutions:

[0008] One of the technical solutions of the present invention is a method for preparing high-lubricity continuous casting mold slag using magnesium reduction slag, comprising the following steps:

[0009] The magnesium reduction slag, coal and flux are mixed and pressed into blocks, and then calcined at high temperature;

[0010] The product obtained by high-temperature roasting is crushed and then subjected to magnetic separation. The non-magnetic material separated by the magnetic separation is mixed with a binder, slurried, and granulated to obtain the high-lubricity continuous casting protection slag.

[0011] A second technical solution of the present invention is a high-lubricity continuous casting protection slag prepared by the above method.

[0012] The present invention discloses the following technical effects:

[0013] The present invention prepares continuous casting protection slag with high-efficiency lubricating performance by mixing magnesium reduction slag with coal and flux, pressing them into blocks, treating them with high-temperature roasting process, and separating slag from iron and magnetic separation process. The method makes full use of the effective components in magnesium reduction slag.

[0014] The method provided by the present invention has a simple process flow, and this method not only has a low production cost, but also has significant environmental benefits, reduces dependence on mineral resources, and reduces the problem of accumulation of industrial waste. It is widely applicable to the metallurgical industry and has broad application prospects and important practical significance. DETAILED DESCRIPTION

[0015] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0016] It should be understood that the terms described in the present invention are only for describing a particular embodiment and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. The intermediate value in any stated value or stated range, and each smaller range between any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0017] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0018] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to the skilled artisan. The present invention description and examples are exemplary only.

[0019] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0020] In the present invention, "%" means mass percentage.

[0021] The present invention prepares high-lubricity continuous casting protection slag by adding coal and flux to magnesium reduction slag, and then undergoing high-temperature roasting and magnetic separation processes. This method makes full use of the effective components in magnesium reduction slag, reduces dependence on mineral raw materials, and not only contributes to the recycling of resources in the metallurgical industry, but also provides a new way for the large-scale resource processing of magnesium reduction slag, with significant economic and environmental benefits.

[0022] A first aspect of the present invention provides a method for preparing high-lubricity continuous casting mold slag using magnesium reduction slag, comprising the following steps:

[0023] The magnesium reduction slag, coal and flux are mixed and pressed into blocks, and then calcined at high temperature;

[0024] The product obtained by high-temperature roasting is crushed and then subjected to magnetic separation. The non-magnetic material separated by the magnetic separation is mixed with a binder, slurried, and granulated to obtain the high-lubricity continuous casting protection slag.

[0025] In some embodiments of the present invention, the magnesium reduction slag comprises the following components in percentage by weight: CaO 30%-50%, SiO 2 15%-28%, Fe 2 O 3 2%-10%, the rest is Al 2 O 3 , MgO and inevitable impurities. In the present invention, by mass percentage, Al 2 O 3 It is 2%-2.8%, and MgO is 3.1%-5.6%.

[0026] In some embodiments of the present invention, before the magnesium reduction slag, coal and flux are mixed, the step of crushing the magnesium reduction slag to a particle size range of 0.05 mm-0.15 mm accounts for ≥90% is also included.

[0027] In some embodiments of the present invention, the coal is high-volatile coal with a volatile content of 35%-60%; the amount of the coal used is 8%-15% of the mass of the magnesium reduction slag.

[0028] In some embodiments of the present invention, the average particle size of the coal is ≤0.02 mm, and the particle size range of 0.01 mm-0.03 mm accounts for ≥90%.

[0029] In some embodiments of the present invention, the flux is calcium fluoride and / or sodium fluoride; the amount of the flux is 1%-5% of the mass of the magnesium reduction slag.

[0030] In some embodiments of the present invention, the particle size of the flux is 0.05 mm-0.2 mm.

[0031] In some embodiments of the present invention, the high temperature calcination is specifically as follows: after keeping the temperature at 1150°C-1250°C for 40min-120min, the temperature is further increased to 1300°C-1400°C and kept for 10min-20min.

[0032] In some embodiments of the present invention, the pressure during pressing into blocks is 20 MPa-45 MPa.

[0033] In some embodiments of the present invention, the iron content in the non-magnetic material is less than 0.03%.

[0034] In some embodiments of the present invention, the binder is water glass; the amount of the binder is 1%-2% of the mass of the magnesium reduction slag.

[0035] In some embodiments of the present invention, the water glass particle size range is 0.02 mm to 0.05 mm, and the proportion is ≥ 85%. The present invention has no special requirements for the selection of the modulus of the water glass, and conventional technical means of those skilled in the art can be selected.

[0036] A second aspect of the present invention provides a high-lubricity continuous casting protection slag prepared by the method described above.

[0037] The technical solutions described in the present invention, unless otherwise specified, are all conventional solutions in the art, and the reagents or raw materials used, unless otherwise specified, are purchased from commercial channels or have been disclosed.

[0038] In order to better understand the present invention, the content of the present invention is further explained below in conjunction with the embodiments, but the content of the present invention is not limited to the following embodiments.

[0039] Example 1

[0040] In this embodiment, the parameters of each raw material are as follows:

[0041] Magnesium reduction slag: CaO is 47.22%, SiO 2 24.55%, Fe 2 O 3 4.10%, Al 2 O 3 The magnesium reduction slag has a particle size range of 0.05-0.15 mm and accounts for 92.88%.

[0042] High volatile coal: The volatile content of high volatile coal is 45.74%, the particle size range of 0.01mm-0.03mm accounts for 95.19%, and the average particle size is 0.017mm.

[0043] Calcium fluoride: The particle size range of calcium fluoride is 0.05-0.16mm.

[0044] Water glass: The water glass with a particle size range of 0.02mm-0.05mm accounts for 89.46%.

[0045] The method for preparing high lubricity continuous casting mold slag using magnesium reduction slag in this embodiment comprises the following steps:

[0046] Step 1. Mix the magnesium reduction slag, high volatile coal and calcium fluoride, press them into blocks at a pressure of 35 MPa, and then perform high-temperature roasting; wherein the amount of high volatile coal is 10% of the mass of the magnesium reduction slag, and the amount of calcium fluoride is 1.8% of the mass of the magnesium reduction slag; the parameters of the high-temperature roasting are set as: first keep warm at 1180°C for 60 minutes, then continue to heat to 1350°C and keep warm for 15 minutes.

[0047] Step 2. The product obtained by high temperature roasting is crushed, and then subjected to magnetic separation treatment, and the iron content of the selected non-magnetic material is 0.01%. Then, the selected non-magnetic material is mixed with 1.5% water glass of the mass of magnesium reduction slag, slurried, and granulated to finally obtain high lubricity continuous casting protection slag.

[0048] The main components of the high lubricity continuous casting protection slag obtained in this embodiment are: CaO 48.54%, SiO 2 25.92%,Fe 2 O 3 3.42%,Al 2 O 3 2.86%, MgO 5.80%, C 7.53%, CaF 2 1.59%, Na 2 O·nSiO 2 The obtained high lubricity continuous casting mold slag has a melting point of 1053.84°C and a viscosity of 0.04 Pa·s at 1300°C.

[0049] Example 2

[0050] In this embodiment, the parameters of each raw material are as follows:

[0051] Magnesium reduction slag: CaO is 42.73%, SiO 2 21.58%, Fe 2 O 3 6.44%, Al 2 O 3 The magnesium reduction slag has a particle size range of 0.05-0.15 mm and accounts for 94.34%.

[0052] High volatile coal: The volatile content of high volatile coal is 49.34%, the particle size range of 0.01mm-0.03mm accounts for 94.19%, and the average particle size is 0.014mm.

[0053] Calcium fluoride: The particle size range of calcium fluoride is 0.07-0.18mm.

[0054] Water glass: The water glass with a particle size range of 0.02mm-0.05mm accounts for 90.91%.

[0055] The method for preparing high lubricity continuous casting mold slag using magnesium reduction slag in this embodiment comprises the following steps:

[0056] Step 1. Mix the magnesium reduction slag, high volatile coal and calcium fluoride, press them into blocks at a pressure of 30 MPa, and then perform high-temperature roasting; wherein the amount of high volatile coal is 8% of the mass of the magnesium reduction slag, and the amount of calcium fluoride is 3.1% of the mass of the magnesium reduction slag; the parameters of the high-temperature roasting are set as: first keep warm at 1200°C for 60 minutes, then continue to heat to 1350°C and keep warm for 20 minutes.

[0057] Step 2. The product obtained by high temperature roasting is crushed, and then subjected to magnetic separation treatment, and the iron content of the selected non-magnetic material is 0.01%. Then, the selected non-magnetic material is mixed with 1.2% water glass of the mass of magnesium reduction slag, slurried, and granulated to finally obtain high lubricity continuous casting protection slag.

[0058] The main components of the high lubricity continuous casting protection slag obtained in this embodiment are as follows: CaO 50.32%, SiO 2 25.74%,Fe 2 O 3 6.37%,Al 2 O 3 1.83%, MgO 3.86%, C 6.68%, CaF 2 2.64%, Na 2 O·nSiO 2 The obtained high lubricity continuous casting mold slag has a melting point of 1051.44°C and a viscosity of 0.04 Pa·s at 1300°C.

[0059] Example 3

[0060] In this embodiment, the parameters of each raw material are as follows:

[0061] Magnesium reduction slag: CaO is 48.65%, SiO 2 20.41%, Fe 2 O 3 4.19%, Al 2 O 3 The magnesium reduction slag has a particle size range of 0.05-0.15 mm and accounts for 96.34%.

[0062] High volatile coal: The volatile content of high volatile coal is 55.12%, the particle size range of 0.01mm-0.03mm accounts for 95.46%, and the average particle size is 0.019mm.

[0063] Calcium fluoride: The particle size range of calcium fluoride is 0.05-0.17mm.

[0064] Water glass: The water glass particle size range is 0.02mm-0.05mm, accounting for 90.01%.

[0065] The method for preparing high lubricity continuous casting mold slag using magnesium reduction slag in this embodiment comprises the following steps:

[0066] Step 1. Mix the magnesium reduction slag, high volatile coal and calcium fluoride, press them into blocks at a pressure of 35 MPa, and then perform high-temperature roasting; wherein the amount of high volatile coal is 9% of the mass of the magnesium reduction slag, and the amount of calcium fluoride is 3.8% of the mass of the magnesium reduction slag; the parameters of the high-temperature roasting are set as: first keep warm at 1210°C for 90 minutes, then continue to heat to 1350°C and keep warm for 20 minutes.

[0067] Step 2. The product obtained by high temperature roasting is crushed, and then subjected to magnetic separation treatment, and the iron content of the selected non-magnetic material is 0.01%. Then, the selected non-magnetic material is mixed with 1.5% water glass of the mass of magnesium reduction slag, slurried, and granulated to finally obtain high lubricity continuous casting protection slag.

[0068] The main components of the high lubricity continuous casting mold slag obtained in this embodiment are as follows: CaO 53.89%, SiO 2 22.61%,Fe 2 O 3 4.19%, Al 2 O 3 2.28%, MgO 3.90%, C 7.81%, CaF 2 2.51%, Na 2 O·nSiO 2 The obtained high lubricity continuous casting mold slag has a melting point of 1047.91°C and a viscosity of 0.03 Pa·s at 1300°C.

[0069] Comparative Example 1

[0070] The only difference from Example 3 is that the amount of high volatile coal used is 3% of the mass of the magnesium reduction slag, and the other steps and parameters are the same as those in Example 3.

[0071] The continuous casting mold slag obtained in this comparative example has a melting point of 1107.83°C and a viscosity of 0.06 Pa·s at 1300°C.

[0072] Comparative Example 2

[0073] The only difference from Example 3 is that the amount of high volatile coal used is 20% of the mass of the magnesium reduction slag, and the other steps and parameters are the same as those in Example 3.

[0074] The continuous casting mold slag obtained in this comparative example has a melting point of 1032.18°C and a viscosity of 0.03 Pa·s at 1300°C.

[0075] The melting point and viscosity of the continuous casting mold slag in this comparative example are slightly reduced, but it does not meet the performance of the mold slag. It has too strong fluidity in the liquid state and is difficult to form a stable slag film.

[0076] Comparative Example 3

[0077] The only difference from Example 3 is that the parameters of high-temperature roasting are set to: 1210° C. for 30 min, and the remaining steps and parameters are the same as those in Example 3.

[0078] The continuous casting mold slag obtained in this comparative example has a melting point of 1062.13° C. and a viscosity of 0.04 Pa·s at 1300° C.

[0079] Comparative Example 4

[0080] The only difference from Example 3 is that the parameters of high-temperature roasting are set as: heating to 1350° C. without keeping warm, and the remaining steps and parameters are the same as those of Example 3.

[0081] The continuous casting mold slag obtained in this comparative example has a melting point of 1060.85°C and a viscosity of 0.04 Pa·s at 1300°C.

[0082] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing high lubricity continuous casting mold slag using magnesium reduction slag, characterized in that: The following steps are involved: The magnesium reduction slag, coal and flux are mixed and pressed into blocks, and then calcined at high temperature; The product obtained by high-temperature roasting is crushed and then subjected to magnetic separation. The non-magnetic material separated by the magnetic separation is mixed with a binder, slurried, and granulated to obtain the high-lubricity continuous casting protection slag.

2. The method for preparing high lubricity continuous casting mold slag using magnesium reduction slag according to claim 1, characterized in that: The magnesium reduction slag comprises the following components in percentage by mass: CaO 30%-50%, SiO2 15%-28%, Fe2O3 2%-10%, and the rest are Al2O3, MgO and inevitable impurities.

3. The method for preparing high lubricity continuous casting mold slag using magnesium reduction slag according to claim 1, characterized in that: The coal is high-volatile coal with a volatile content of 35%-60%; the amount of the coal used is 8%-15% of the mass of the magnesium reduction slag.

4. The method for preparing high lubricity continuous casting mold slag using magnesium reduction slag according to claim 1, characterized in that: The flux is calcium fluoride and / or sodium fluoride; the amount of the flux is 1%-5% of the mass of the magnesium reduction slag.

5. The method for preparing high lubricity continuous casting mold slag using magnesium reduction slag according to claim 1, characterized in that: The high temperature calcination is specifically as follows: after keeping the temperature at 1150° C.-1250° C. for 40 min-120 min, the temperature is further raised to 1300° C.-1400° C. and kept for 10 min-20 min.

6. The method for preparing high lubricity continuous casting mold slag using magnesium reduction slag according to claim 1, characterized in that: The iron content in the non-magnetic material is less than 0.03%.

7. The method for preparing high lubricity continuous casting mold slag using magnesium reduction slag according to claim 1, characterized in that: The binder is water glass; the amount of the binder is 1%-2% of the mass of the magnesium reduction slag.

8. A high lubricity continuous casting protection slag prepared by the method according to any one of claims 1 to 7.