Method for preparing magnesium refractory material from magnesium-rich tailings

Abstract

The invention provides a method for preparing a magnesium refractory material from magnesium-rich tailings. Magnesium-rich slag and an additive are used as raw materials, the magnesium-rich slag and the additive are matched with each other, after a binder is added, compression molding and sintering are conducted, the magnesium refractory material is obtained, the additive is selected from at least one of magnesium oxide, aluminum oxide and zirconium oxide, the addition amount of the additive is 5-50% of the mass of the magnesium-rich slag, and the binder is a magnesium chloride solution; the magnesium-rich slag is magnesium slag with MgO greater than or equal to 40%. According to the invention, high-proportion application of the magnesium-rich slag is realized for the first time, and the process has the characteristics of simple flow, solid waste resource utilization and the like. All components of magnesium, iron and silicon in the tailings are utilized, technical support is provided for efficient utilization of the magnesium-rich tailings in China, and the method has very wide popularization and application prospects.

Description

Technical Field

[0001] The invention relates to the technical field of refractory materials, and in particular to a method for preparing a magnesia refractory material by utilizing magnesium-rich tailings. Background Art

[0002] Magnesium refractory materials are indispensable basic materials for high temperature industries. They have excellent high refractoriness and strong slag resistance. They can maintain stable performance in extremely high temperature environments and are widely used in key fields in high temperature environments such as metallurgy and cement production. Magnesium is the main raw material of magnesium refractory materials, and its main sources are natural magnesite, seawater, salt lake brine, calcite, serpentine, brucite, slag and waste refractory materials. Among the existing magnesium refractory patents, such as CN118561613B and CN117865653B, waste magnesium refractory materials are used as magnesium sources; CN115073142B, CN108840692A, and CN107686339A use fused magnesia as magnesium sources.

[0003] With the continuous development of metallurgical technology, a large number of ores are mainly extracted with boron, iron, aluminum, calcium, etc., while magnesium enters the tailings, which fails to realize resource utilization and causes waste. Therefore, the study of the method of preparing excellent magnesium refractory materials from magnesium-rich tailings is of great economic value and social benefit and is of great significance.

[0004] There are records of using tailings to prepare magnesia refractory materials in the prior art. For example, our team has mentioned in patent CN113060741B that a simple method of using leached slag to prepare refractory materials is involved. The leached slag for extracting boron and iron is pressed and formed at a pressure of 100-150MPa and dried. After treatment, it is roasted at 1300-1350℃ in an oxidizing atmosphere for 2-3h to obtain a magnesia refractory material, preferably with a refractoriness of 1650℃~1680℃, a bulk density and an apparent porosity of 1.53g / cm3 and 1.89% respectively. In this patent, no additives are added in the preparation process of the refractory material, the preparation method is simple, and the refractory material performance is poor. In patent C N106810281B describes a method for preparing forsterite refractory materials from nickel-iron alloy tailings. In the patent, magnesium oxide is used as an additive, and the ratio of MgO / SiO2, MgO / FeO, MgO / Al2O3, Al2O3 / SiO2, (MgO+CaO) / (SiO2+Al2O3) is adjusted to a specific ratio, and a magnesium refractory material is obtained after roasting. However, under the preferred conditions, the refractoriness of the refractory material is 1610-1660°C, the compressive strength is 87.5-89.6MPa, the bulk density is 2.27-2.33g / cm3, and the apparent porosity is 26.88-27.78%. Therefore, the current method for preparing refractory materials from magnesium-rich tailings has low refractoriness and compressive strength, and cannot meet the requirements of the metallurgical industry that require higher refractoriness.

[0005] Therefore, it is very meaningful to use magnesium-rich tailings to prepare magnesium refractory materials with high refractoriness and high compressive strength. Summary of the invention

[0006] In view of the above technical problems, in order to further improve the compressive strength and refractory temperature of the product, the present invention provides a method for preparing a magnesia refractory material using magnesium-rich tailings, which not only realizes the comprehensive utilization of tailings, but also further improves the comprehensive performance of the refractory material. In the present invention, the magnesia refractory material prepared using magnesium-rich tailings can reach a refractoriness of 1800°C and a compressive strength of 106.7 MPa.

[0007] The present invention realizes for the first time the utilization of magnesium-rich slag in a large proportion and can also obtain refractory materials with extremely superior performance.

[0008] The technical solution adopted by the present invention is: The present invention provides a method for preparing a magnesia refractory material from magnesium-rich tailings, wherein magnesium-rich slag and an additive are used as raw materials, the magnesium-rich slag and the additive are matched with each other, a binder is added, the magnesia refractory material is obtained by pressing and molding, and sintering, wherein the additive is selected from at least one of magnesium oxide, aluminum oxide, and zirconium oxide, and the additive is added in an amount of 5 wt.% to 50 wt.% of the mass of the magnesium-rich slag, and the binder is a magnesium chloride solution. The prepared refractory material has excellent thermal shock resistance, refractoriness, bulk density, compressive strength and apparent porosity.

[0009] The present invention provides a method for preparing magnesia refractory materials from magnesium-rich tailings, wherein the binder is preferably 1.4 g / cm 3 The amount of binder used is 3-5% of the raw material mass.

[0010] The present invention provides a method for preparing a magnesia refractory material from magnesium-rich tailings, wherein the magnesium-rich slag is magnesium slag with MgO≥35%. In the present invention, the magnesium slag may be at least one of beneficiation slag and smelting slag. The water content of the magnesium-rich tailings is reduced after pre-baking treatment, and the finally obtained magnesium refractory material has better performance, and the pre-baking temperature is 400°C or above, preferably 800°C. The adsorbed water / crystallized water content in the magnesium-rich tailings is ≥5 wt.%.

[0011] After pre-baking, the magnesium-rich slag was mixed with the additives and 1.4 g / cm 3 The solution is used as a binder and is formed through a pressing process. The pressure range of the pressing process is 50-10000 MPa, preferably 50-2000 MPa, and more preferably 100 MPa.

[0012] The sintering includes: calcining at 800-1700°C, preferably 1000-1500°C, and more preferably 1300°C; the calcining time is more than 30 minutes, preferably 90-180 minutes, and more preferably 180 minutes.

[0013] Preferably, the present invention provides a method for preparing a magnesia refractory material from magnesium-rich tailings, wherein the magnesium-rich slag mainly contains the following chemical components (expressed in the form of oxides) in terms of mass percentage, including: MgO 40-55%, preferably 44-55%, more preferably 55%; SiO2 0-30%, preferably 0-20%, more preferably 20%; Fe2O30-40%, preferably 5-20%, further preferably 8%; FeO 0-40%, preferably 5-20%, more preferably 8%; B2O3 0-10%, preferably 0-5%, more preferably 0-1%; Al2O3 1-20%, preferably 1-11%, more preferably 9-11%; CaO 0-10%, preferably 0-5%, more preferably 5%; Na2O 0-10%, preferably 0-5%, more preferably 0-1%.

[0014] As a further preference, the raw materials are composed of magnesium-rich slag, magnesium oxide, aluminum oxide and zirconium oxide, wherein the ratio (in mass percentage) is: magnesium-rich slag 70%-90%, magnesium oxide 0-12%, aluminum oxide 0-12%, zirconium oxide 0-10%, and at least one of magnesium oxide, aluminum oxide and zirconium oxide is not zero.

[0015] As a further preference, the raw materials are composed of magnesium-rich slag, magnesium oxide, aluminum oxide and zirconium oxide, wherein the ratio (in mass percentage) is: magnesium-rich slag 75%-85%, magnesium oxide 5%~10%, aluminum oxide 5%~10%, zirconium oxide 0~10%, and the sum of the mass percentages of magnesium-rich slag, magnesium oxide, aluminum oxide and zirconium oxide is 100%.

[0016] As a further preferred embodiment, the raw material is composed of magnesium-rich slag, magnesium oxide and aluminum oxide, wherein the proportion (by mass percentage) is: the mass percentage of magnesium-rich slag is 80-82%, magnesium oxide is 10%, and aluminum oxide is 8-10%.

[0017] As a further preferred embodiment, the raw material is composed of magnesium-rich slag, magnesium oxide and aluminum oxide in a mass ratio of magnesium-rich slag: magnesium oxide: aluminum oxide = 82:10:8.

[0018] The method for preparing the magnesia refractory material of the present invention comprises the following steps: (1) preparing raw materials according to the proportion, stirring and mixing the raw materials according to the design, adding a binder and mixing evenly to obtain a mixture; (2) pouring the mixture in step (1) into a mold, applying a pressure of 50-10000 MPa, preferably 50-2000 MPa, and more preferably 100 MPa, to press and shape the mixture to obtain an initial mass; (3) Then the initial mass obtained in step (2) is placed at 800-1700°C, preferably 1000-1500°C, and more preferably 1300°C for roasting, and the roasting time is more than 30 minutes, preferably 90-180 minutes, and more preferably 180 minutes, to obtain a magnesia refractory material. The optimized process of the present invention realizes for the first time that at a relatively low temperature (such as 1300°C), a high-quality product with a compressive strength greater than 105 MPa, a refractoriness of 1800°C, and a thermal shock resistance (test temperature 1100°C) of more than or equal to 6 times can be obtained.

[0019] After optimization, the product obtained by the present invention has an apparent porosity of 15.9%, a bulk density of 3.05 g / cm3, a compressive strength of 106.7 MPa, a refractoriness of 1800°C, and a thermal shock resistance (test temperature 1100°C) of 7 times.

[0020] The advantages of the present invention are: 1. In the present invention, the addition ratio of magnesium-rich slag is high, which can fully realize the value-added utilization of solid waste. 2. The process of the present invention can realize the preparation of excellent magnesia refractory materials, and the proportion and type of additives used can be adjusted according to demand. 3. The raw materials of the present invention are widely available, and the refractory materials prepared are excellent in performance and high in added value.

[0021] In summary, the present invention has the characteristics of simple process flow, low energy consumption, low cost, high product added value, etc. It provides a feasible way to prepare products for the efficient development and utilization of abundant magnesium-rich tailings resources in my country, and has a very broad prospect for promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Attached Figure 1 Graph showing particle size distribution of magnesium-rich slag used in the examples and comparative examples of the present invention. DETAILED DESCRIPTION

[0023] In the embodiments and comparative examples of the present invention, the specific composition of the magnesium-rich slag used is shown in Table 1 below, and the particle size is as follows: Figure 1 As shown:

[0024] Example 1

[0025] A method for preparing a magnesia refractory material, which is prepared from the following proportioned components: magnesium-rich slag (100%).

[0026] The method for preparing the magnesia refractory material described in this embodiment comprises the following steps: 1. Prepare the raw materials according to the ratio: pre-roast the magnesium-rich slag at 800℃ for 1h to obtain the pre-roasted magnesium-rich slag, add 1.4g / cm 3 A magnesium chloride solution is used as a binder, and the solution is added in an amount of 4% of the total amount, and stirred and mixed evenly to obtain a mixture; 2. Pour the mixture in step (1) into a briquetting mold, and then apply a force of 100 MPa for 1 min to obtain an initial briquette; 3. The agglomerate in step (2) is roasted at 1300°C for 3 hours to obtain a magnesia refractory material.

[0027] 4. The performance test results of the magnesia refractory material prepared in this embodiment are as follows: the apparent porosity is 6.56%, the bulk density is 3.36 g / cm 3 The compressive strength is 111.7 MPa, the thermal shock resistance (test temperature 1100℃) is 2 times, and the refractoriness is 1700℃.

[0028] Comparative Example 1 The other conditions are the same as those in Example 1, except that the agglomerate described in step (2) of Example 1 is calcined at 1100°C for 3 hours to obtain a magnesia refractory material. The magnesia refractory material obtained in this comparative example has poorer performance than that of Example 1, and its performance test results are as follows: apparent porosity is 46.71%, sample volume density is 2.13 g / cm3, compressive strength is 37.8 MPa, refractoriness is 1700°C, and thermal shock resistance (test temperature 1100°C) is 2 times.

[0029] Example 2

[0030] The other conditions are consistent with those in Example 1, except that the component ratio is changed to: magnesium-rich slag (90 wt.%), magnesium oxide (10 wt.%), and the magnesium oxide particle size is -200 mesh. The performance test results of the magnesium refractory material prepared in this example are: apparent porosity is 2.76%, bulk density is 3.41 g / cm3, compressive strength is 110.6 MPa, thermal shock resistance (test temperature 1100°C) is 4 times, and refractoriness is 1720°C.

[0031] Comparative Example 2 The other conditions are the same as those in Example 1, except that the raw material composition ratio in Example 2 is changed to: magnesium-rich slag (95 wt.%), magnesium oxide (5 wt.%). The magnesia refractory material prepared in this comparative example is inferior to that in Example 2, and its performance test results are: apparent porosity is 3%, and the sample volume density is 3.35 g / cm 3 , the compressive strength is 107 MPa, the refractoriness is 1720℃, and the thermal shock resistance (test temperature 1100℃) is 3 times.

[0032] Example 3

[0033] The other conditions are the same as those in Example 1, except that the composition ratio is changed to: magnesium-rich slag (80 wt.%), magnesium oxide (10 wt.%), zirconium oxide (10 wt.%), and the particle size of magnesium oxide and zirconium oxide is -200 mesh; the performance test results of the magnesia refractory material prepared in this example are: the apparent porosity is 2.1%, and the bulk density is 3.45 g / cm 3, compressive strength is 103MPa, refractoriness is 1700℃, thermal shock resistance (test temperature 1100℃) is 3 times.

[0034] Example 4

[0035] The other conditions are the same as those in Example 1, except that the raw material composition ratio is changed to: magnesium-rich slag (86 wt.%), magnesium oxide (10 wt.%), aluminum oxide (4 wt.%), and the particle size of magnesium oxide and aluminum oxide is -200 mesh. The performance test results of the prepared product are: apparent porosity is 8%, and the sample volume density is 3.23 g / cm 3 , the compressive strength is 102 MPa, the refractoriness is 1780℃, and the thermal shock resistance (test temperature 1100℃) is 4 times.

[0036] Example 5

[0037] The other conditions are the same as those in Example 4, except that: magnesium-rich slag (84 wt.%), magnesium oxide (10 wt.%), and aluminum oxide (6 wt.%). The product performance test results are: apparent porosity 16%, sample volume density 3.03 g / cm 3 The compressive strength is 98MPa, the refractoriness is 1780℃, and the thermal shock resistance (test temperature 1100℃) is 6 times.

[0038] Example 6

[0039] The other conditions are the same as those in Example 4, except that the raw material composition ratio is changed to: magnesium-rich slag (82 wt.%), magnesium oxide (10 wt.%), and aluminum oxide (8 wt.%). The performance test results of the magnesium refractory material prepared in this example are: the apparent porosity is 15.9%, and the bulk density is 3.05 g / cm 3 The compressive strength is 106.7 MPa, the refractoriness is 1800 ℃, and the thermal shock resistance (test temperature 1100 ℃) is 7 times.

[0040] The embodiments described above are merely descriptions of preferred implementation modes of the present invention and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for preparing magnesia refractory materials from magnesium-rich tailings, characterized in that: The magnesium-rich slag and additives are used as raw materials, the magnesium-rich slag and the additives are mixed with each other, and after adding a binder, they are pressed into shape and roasted to obtain a magnesium refractory material. The additive is selected from at least one of magnesium oxide, aluminum oxide, and zirconium oxide, and the additive is 5-50% of the mass of the magnesium-rich slag. The binder is a magnesium chloride solution; the magnesium-rich slag is a magnesium slag with MgO≥40%.

2. The method for preparing magnesia refractory material from magnesium-rich tailings according to claim 1, characterized in that: The binder is 1.3g / cm 3 The amount of binder is 3-5% of the weight of the raw material.

3. The method for preparing magnesia refractory material from magnesium-rich tailings according to claim 1, characterized in that: The magnesium-rich slag mainly contains the following chemical components, expressed in the form of oxides and in terms of mass percentage, including: MgO 40-55%, preferably 44%-55%, more preferably 55%; SiO2 0-30%, preferably 0%-20%, more preferably 20%; Fe2O3 0-40%, preferably 5%-20%, more preferably 8%; FeO 0-40%, preferably 5%-20%, more preferably 8%; B2O3 0-10%, preferably 0%-5%, more preferably 0-1%; Al2O31-20%, preferably 1%-11%, more preferably 9-11%; CaO 0-10%, preferably 0-5%, more preferably 5%; Na2O 0-10%, preferably 0-5%, more preferably 0-1%.

4. The method for preparing magnesia refractory material from magnesium-rich tailings according to claim 1, characterized in that: The raw materials are composed of magnesium-rich slag, magnesium oxide, aluminum oxide and zirconium oxide, wherein the proportion (by mass percentage) is: magnesium-rich slag 70%-90%, magnesium oxide 0-12%, aluminum oxide 0-12%, zirconium oxide 0-10%; and at least one of magnesium oxide, aluminum oxide and zirconium oxide is not zero.

5. The method for preparing magnesia refractory material from magnesium-rich tailings according to claim 1, characterized in that: The raw materials are composed of magnesium-rich slag, magnesium oxide, aluminum oxide and zirconium oxide, wherein the proportions (by mass percentage) are: magnesium-rich slag 75%-85%, magnesium oxide 5%~10%, aluminum oxide 5%~10%, zirconium oxide 0~10%, and the sum of the mass percentages of magnesium-rich slag, magnesium oxide, aluminum oxide and zirconium oxide is 100%.

6. The method for preparing magnesia refractory material from magnesium-rich tailings according to claim 1, characterized in that: The raw materials are composed of magnesium-rich slag, magnesium oxide and aluminum oxide, wherein the proportion (by mass percentage) is: magnesium-rich slag 80%-82%, magnesium oxide 10%, and aluminum oxide 8%-10%.

7. The method for preparing magnesia refractory material from magnesium-rich tailings according to claim 1, characterized in that: The raw materials are magnesium-rich slag, magnesium oxide, and aluminum oxide in a mass ratio of magnesium-rich slag: magnesium oxide: aluminum oxide = 82: 10:8 composition.

8. The method for preparing magnesia refractory material from magnesium-rich tailings according to claim 1, characterized in that: The magnesium-rich tailings are pre-calcined, and the water content of the magnesium-rich tailings after the pre-calcination is reduced. The pre-calcination temperature is 400° C. or above, preferably 800° C.; the adsorbed water / crystallized water content in the magnesium-rich tailings is ≥5wt.%.

9. The method for preparing magnesia refractory material from magnesium-rich tailings according to claim 1, characterized in that: After the magnesium-rich slag is mixed with the additive, 1.4 g / cm 3 The magnesium chloride solution is used as a binder and is formed through a pressing process, wherein the pressure range of the pressing process is 50-10000 MPa, preferably 50-2000 MPa, and more preferably 100 MPa; The sintering includes: calcining at 800-1700°C, preferably 1000-1500°C, and more preferably 1300°C; the calcining time is more than 30 minutes, preferably 90-180 minutes, and more preferably 180 minutes.

10. The method for preparing magnesia refractory material from magnesium-rich tailings according to claim 1, characterized in that: The following steps are involved: (1) preparing raw materials according to a ratio, stirring and mixing the raw materials according to the ratio, adding a binder and mixing them evenly to obtain a mixture; (2) pouring the mixture in step (1) into a mold, applying 50-10000 MPa, 50-10000 MPa, preferably 50-2000 MPa, more preferably 100 MPa, to form a compression mold to obtain an initial mass; (3) Then the initial agglomerate obtained in step (2) is placed at 800-1700° C., preferably 1000-1500° C., and more preferably 1300° C. for roasting, and the roasting time is more than 30 minutes, preferably 90-180 minutes, and more preferably 180 minutes, to obtain a magnesia refractory material.

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