A method for preparing mullite refractory materials and mullite refractory materials

Abstract

The present invention discloses a method for preparing mullite refractory materials and the mullite refractory materials. The method includes: S1, mixing 5-15 parts by weight of gold tailings slag, 30-45 parts by weight of bauxite and a binder, and grinding to prepare a first mixture; S2, adding 3-8 parts by weight of alumina and 6-10 parts by weight of zirconia to the first mixture and grinding to prepare a second mixture; S3, dry-pressing the second mixture into a shape; S4, sintering to prepare the mullite refractory materials. The mullite refractory materials obtained by the present invention have a high content of mullite phase, uniform distribution, strong chemical erosion resistance, high stability, and good comprehensive performance of the refractory materials.

Description

Technical Field

[0001] The present invention relates to the technical field of mullite refractory materials, and particularly to a method for preparing mullite refractory materials and the mullite refractory materials. Background Art

[0002] As gold mineral resources are continuously exploited, the storage of gold tailings will occupy a large amount of land, and a large amount of gold tailings slag is mostly piled up in landfills. In contrast, the comprehensive utilization of gold tailings lags far behind that of other bulk solid wastes. At present, gold tailings have become bulk solid wastes with a relatively low industrial comprehensive utilization rate. After the gold tailings are classified, according to the definition and classification of tailings in "Reference Materials for Tailings Facility Design", those with a particle size greater than 75 mesh accounting for more than 40% (volume fraction) of the total particles are called coarse-grained tailings. The coarser-grained tailings can be used as concrete aggregates and construction sand, etc., and have a relatively large application range. Those with a particle size less than 75 mesh accounting for more than 85% (volume fraction) of the total particles are called fine-grained tailings. Since the use of the finer-grained tailings is relatively small, most of the tailings stored in the tailings pond are fine-grained gold tailings. At present, the main ways of comprehensive utilization of gold tailings are the filling of mined-out areas in underground mining, and secondly, for building materials. Summary of the Invention

[0003] The main purpose of the present invention is to overcome the defects of the above background art, and to provide a method for preparing mullite refractory materials and the mullite refractory materials.

[0004] To achieve the above purpose, the present invention adopts the following technical solutions:

[0005] A method for preparing mullite refractory materials includes the following steps: S1. Mix 5-15 parts by weight of gold tailings slag, 30-45 parts by weight of bauxite and a binder, and grind them to prepare a first mixture; S2. Add 3-8 parts by weight of alumina and 6-10 parts by weight of zirconia to the first mixture and grind to prepare a second mixture; S3. Dry-press the second mixture into a shape; S4. After sintering, prepare the mullite refractory materials.

[0006] In some embodiments of the present invention, the binder accounts for 1% of the total mass of the raw materials.

[0007] In some embodiments of the present invention, the binder is selected from one or more of industrial dextrin, sodium carboxymethylcellulose or calcium lignosulfonate.

[0008] In some embodiments of the present invention, in step S1, the grinding is performed until the particle size ≤ 5 μm.

[0009] In some embodiments of the present invention, in step S1, wet ball milling is carried out by adding water, and the mass of the added water accounts for 5%-15% of the total mass of the gold tailings slag, bauxite and binder; after grinding, drying treatment is carried out, the drying temperature is 100-110°C, and the drying time is 8-13h.

[0010] In some embodiments of the present invention, in step S2, grinding is carried out until the particle size ≤ 3 microns.

[0011] In some embodiments of the present invention, in step S2, dry ball milling is carried out, and the ball milling time is 4-6h.

[0012] In some embodiments of the present invention, in step S3, the pressure of dry pressing is 60-200 Mpa.

[0013] In some embodiments of the present invention, in step S4, the sintering includes heating to 1200-1300°C at a rate of 3-8°C / min, holding for 1-3h, then heating to 1400-1500°C at a rate of 3-6°C / min, holding for 3-5h, and then cooling with the furnace.

[0014] The present invention also provides a mullite refractory material, which includes 5-15 parts by weight of gold tailings slag, 30-45 parts of bauxite, 3-8 parts of alumina and 6-10 parts of zirconia.

[0015] The present invention has the following beneficial effects:

[0016] The mullite refractory material and the method for preparing the mullite refractory material proposed by the present invention use gold tailings slag as the raw material. The prepared mullite refractory material has mullite phase as the main crystal phase, with a high content of mullite phase and uniform distribution. Therefore, the material has good refractoriness and comprehensive properties. The refractory material uses gold tailings slag and bauxite as the main raw materials, compounded with industrial alumina and zirconia. The added industrial alumina and zirconia improve the alkali metal and alkaline earth metal erosion resistance of the refractory material. Moreover, the main component of the gold tailings slag used in the present invention has a high silicon dioxide content, few harmful impurities, and extremely fine particle size, with a particle size ≤ 10 microns. At the same time, the tailings slag does not contain cyanide and can be directly utilized without detoxification treatment.

[0017] Compared with the prior art, the present invention also has the following advantages: (1) The mullite refractory material of the present invention has a high content of mullite phase, uniform distribution, strong chemical erosion resistance, high stability, and good comprehensive properties of the refractory material; (2) By a simple and feasible method, low-value gold tailings slag is transformed into high-value mullite refractory material; (3) The extremely fine particle size of the gold tailings slag reduces the crushing cost and energy consumption.

[0018] Other beneficial effects in the embodiments of the present invention will be further described below. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a flowchart of a method for preparing mullite refractory materials in an embodiment of the present invention;

[0020] Figure 2 is a process flowchart of a method for preparing mullite refractory materials in an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0021] The present invention will be further described below with reference to the accompanying drawings and preferred embodiments. It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments may be combined with each other.

[0022] It should be noted that the orientation terms such as left, right, up, down, top, bottom, etc. in this embodiment are only relative concepts to each other or are referenced based on the normal use state of the product, and should not be considered restrictive.

[0023] Mullite is an aluminosilicate mineral with properties such as high refractoriness, good thermal shock resistance, chemical erosion resistance, creep resistance, high load softening temperature, good volume stability, and strong electrical insulation. It is an ideal high-grade refractory material and is widely used in industries such as metallurgy, glass, ceramics, chemistry, electric power, national defense, gas, and cement. Patent 202211284217.0 proposes a method for preparing mullite refractory materials using coal gangue as a raw material; Patent 201010265770.0 uses aluminum plant sludge and pyrophyllite as raw materials to produce mullite refractory materials; Patent 202210481752.9 proposes a high-strength and high-microporous mullite refractory material based on coal gangue and its preparation method; If fine-grained gold tailings slag can be used as a raw material for refractory materials, it will realize the development and value-added utilization of gold tailings slag in the field of refractory materials, and is also conducive to reducing the production cost of refractory materials, opening up a new way for the recycling of resources.

[0024] As described above, the following embodiments of the present invention propose a method for preparing mullite refractory materials, referring to Figure 1 and Figure 2 , which includes the following steps: S1. Grind 5 - 15 parts by weight of gold tailings slag, 30 - 45 parts by weight of bauxite, and a binder to prepare a first mixture; S2. Add 3 - 8 parts by weight of alumina and 6 - 10 parts by weight of zirconia to the first mixture and grind to prepare a second mixture; S3. Dry-press the second mixture into a shape; S4. After sintering, prepare the mullite refractory material.

[0025] An embodiment of the present invention also provides a mullite refractory material, which comprises 5-15 parts by weight of gold tailings slag, 30-45 parts by weight of bauxite, 3-8 parts by weight of alumina, and 6-10 parts by weight of zirconia.

[0026] In the method for preparing a mullite refractory material from gold tailings slag according to the embodiment of the present invention, the prepared mullite refractory material has mullite phase as the main crystal phase. Due to the high content and uniform distribution of the mullite phase, the material has good refractoriness and comprehensive properties. The refractory material uses gold tailings slag and bauxite as the main raw materials, and is compounded with industrial alumina and zirconia. The additionally added industrial alumina and zirconia improve the alkali metal and alkaline earth metal erosion resistance of the refractory material. The gold tailings slag used in the present invention has a high content of main component silicon dioxide, few harmful impurities, and extremely fine particle size, with a particle size ≤ 10 microns. At the same time, the tailings slag does not contain cyanide and can be directly utilized without detoxification treatment.

[0027] Refer to Figure 2 , in the method for preparing a mullite refractory material from gold tailings slag according to the embodiment of the present invention, the technological steps are as follows:

[0028] Material preparation

[0029] By weight, the mullite refractory material is composed of the following raw materials: 5-15 parts of gold tailings slag, 30-45 parts of bauxite, 3-8 parts of industrial alumina, and 6-10 parts of zirconia (ZrO2), and 1% of the total mass of the raw materials is a binder.

[0030] Among them, the chemical composition of the gold tailings slag is: SiO2 70.03wt%, Al2O3 20.40wt%, CaO 0.02wt%, MgO 2.51wt%, Fe2O3 3.56wt%, TiO2 0.15wt%, K2O 1.53wt%, Na2O 0.71wt%, and loss on ignition 1.09wt%.

[0031] The chemical composition of the bauxite is: SiO2 6.5wt%, Al2O3 84.45wt%, CaO 0.41wt%, MgO 0.1wt%, Fe2O3 2.27wt%, TiO2 3.64wt%, K2O 0.18wt%, Na2O 0.01wt%, and loss on ignition 0.03wt%.

[0032] The binder is preferably at least one or more of industrial dextrin, sodium carboxymethyl cellulose, or calcium lignosulfonate.

[0033] Mixing

[0034] S1. Wet ball milling is carried out on the mixture of gold tailings slag, bauxite and binder by adding water. The mass of the added water accounts for 5%-15% of the total mass of the mixture of gold tailings slag, bauxite and binder, and it is ground to a particle size of ≤5 μm; then drying treatment is carried out, the temperature of the drying treatment is 100-110 °C, and the drying time is 8-13 h to obtain the first mixture.

[0035] S2. Industrial alumina and zirconia are added to the first mixture for dry ball milling. The ball milling time is 4-6 h, and it is ground to a particle size of ≤3 μm to obtain the second mixture.

[0036] Dry pressing

[0037] S3. The second mixture is subjected to dry pressing, and the pressure is 60-200 MPa

[0038] Sintering

[0039] S4. Then sintering is carried out. The sintering is heated at a rate of 3-8 °C / min to 1200-1300 °C, held for 1-3 h, then heated at a rate of 3-6 °C / min to 1400-1500 °C, held for 3-5 h, and finally cooled with the furnace to obtain the mullite refractory material prepared from gold tailings slag as the raw material.

[0040] Example 1

[0041] 1. Preparation of materials

[0042] Calculated by weight, the mullite refractory material is composed of the following raw materials: 8 parts of gold tailings slag, 35 parts of bauxite, 3 parts of industrial alumina and 6 parts of zirconia, and 1% of the total mass of the raw materials as the binder.

[0043] Among them, the chemical composition of the gold tailings slag is: SiO2 70.03 wt%, Al2O3 20.40 wt%, CaO 0.02 wt%, MgO 2.51 wt%, Fe2O3 3.56 wt%, TiO2 0.15 wt%, K2O 1.53 wt%, Na2O 0.71 wt%, loss on ignition 1.09 wt%.

[0044] The chemical composition of the bauxite is: SiO2 6.5 wt%, Al2O3 84.45 wt%, CaO 0.41 wt%, MgO 0.1 wt%, Fe2O3 2.27 wt%, TiO2 3.64 wt%, K2O 0.18 wt%, Na2O 0.01 wt%, loss on ignition 0.03 wt%.

[0045] The binder is selected as industrial dextrin.

[0046] 2. Mixing

[0047] The mixture of gold tailings slag, bauxite and binder is wet ball-milled with water. The mass of the added water accounts for 15% of the total mass of the gold tailings slag, bauxite and binder mixture, and it is ground to a particle size of ≤5 μm; then it is dried. The drying temperature is 100 °C and the drying time is 13 h to obtain the first mixture. Industrial alumina and zirconia are added to the first mixture for dry ball-milling. The ball-milling time is 4 h and it is ground to a particle size of ≤3 μm to obtain the second mixture.

[0048] 3. Dry pressing

[0049] The second mixture is dry-pressed into shape under a pressure of 100 MPa

[0050] 4. Sintering

[0051] Then it is sintered. The sintering process is to heat up to 1250 °C at a rate of 3 °C / min, hold for 1 h, and finally heat up to 1400 °C at a rate of 3 °C / min and hold for 5 h. Finally, it is cooled in the furnace to obtain the mullite refractory material prepared from gold tailings slag.

[0052] Example 2

[0053] 1. Preparation of materials

[0054] By weight, the mullite refractory material is composed of the following raw materials: 15 parts of gold tailings slag, 30 parts of bauxite, 6 parts of industrial alumina, 10 parts of zirconia, and a binder accounting for 1% of the total mass of the raw materials.

[0055] Among them, the chemical composition of the gold tailings slag is: SiO2 70.03 wt%, Al2O3 20.40 wt%, CaO 0.02 wt%, MgO 2.51 wt%, Fe2O3 3.56 wt%, TiO2 0.15 wt%, K2O 1.53 wt%, Na2O 0.71 wt%, loss on ignition 1.09 wt%.

[0056] The chemical composition of the bauxite is: SiO2 6.5 wt%, Al2O3 84.45 wt%, CaO 0.41 wt%, MgO 0.1 wt%, Fe2O3 2.27 wt%, TiO2 3.64 wt%, K2O 0.18 wt%, Na2O 0.01 wt%, loss on ignition 0.03 wt%.

[0057] The binder is selected as sodium carboxymethyl cellulose.

[0058] 2. Mixing

[0059] A mixture of gold tailings slag, bauxite and binder is wet ball-milled with water. The mass of water added accounts for 5% of the total mass of the mixture of gold tailings slag, bauxite and binder, and it is ground to a particle size of ≤5 μm. Then, a drying treatment is carried out. The drying temperature is 105°C and the drying time is 10 h to obtain a first mixture. Industrial alumina and zirconia are added to the first mixture for dry ball-milling. The ball-milling time is 6 h, and it is ground to a particle size of ≤3 μm to obtain a second mixture.

[0060] 3. Dry pressing

[0061] The second mixture is dry-pressed, and the pressure is 60 MPa.

[0062] 4. Sintering

[0063] Then, sintering is carried out. The temperature is raised to 1300°C at a rate of 8°C / min, held for 3 h, and finally the temperature is raised to 1500°C at a rate of 6°C / min and held for 3 h. Finally, it is cooled with the furnace to obtain a mullite refractory material prepared from gold tailings slag as the raw material.

[0064] Example 3

[0065] 1. Preparation of materials

[0066] By weight, the mullite refractory material is composed of the following raw materials: 5 parts of gold tailings slag, 45 parts of bauxite, 3 parts of industrial alumina, 7 parts of zirconia, and 1% of the total mass of the raw materials as a binder.

[0067] Among them, the chemical composition of the gold tailings slag is: SiO2 70.03 wt%, Al2O3 20.40 wt%, CaO 0.02 wt%, MgO 2.51 wt%, Fe2O3 3.56 wt%, TiO2 0.15 wt%, K2O 1.53 wt%, Na2O 0.71 wt%, and loss on ignition 1.09 wt%.

[0068] The chemical composition of the bauxite is: SiO2 6.5 wt%, Al2O3 84.45 wt%, CaO 0.41 wt%, MgO 0.1 wt%, Fe2O3 2.27 wt%, TiO2 3.64 wt%, K2O 0.18 wt%, Na2O 0.01 wt%, and loss on ignition 0.03 wt%.

[0069] The binder is selected as calcium lignosulfonate.

[0070] 2. Mixing

[0071] The mixture of gold tailings slag, bauxite and binder is wet ball-milled with water. The mass of water added accounts for 12% of the total mass of the mixture of gold tailings slag, bauxite and binder, and it is ground to a particle size of ≤5 μm; then it is dried. The drying temperature is 110 °C and the drying time is 11 h to obtain the first mixture. Industrial alumina and zirconia are added to the first mixture for dry ball-milling. The ball-milling time is 5 h and it is ground to a particle size of ≤3 μm to obtain the second mixture.

[0072] 3. Dry pressing

[0073] The second mixture is dry-pressed, and the pressure is 200 Mpa.

[0074] 4. Sintering

[0075] Then it is sintered. The sintering process is to heat up to 1230 °C at a rate of 5 °C / min, hold for 2.5 h, and finally heat up to 1430 °C at a rate of 5 °C / min, hold for 4.2 h, and finally cool down with the furnace to obtain the mullite refractory material prepared from gold tailings slag.

[0076] Example 4

[0077] 1. Preparation of materials

[0078] By weight, the mullite refractory material is composed of the following raw materials: 10 parts of gold tailings slag, 40 parts of bauxite, 8 parts of industrial alumina, 8 parts of zirconia, and a binder accounting for 1% of the total mass of the raw materials.

[0079] Among them, the chemical composition of the gold tailings slag is: SiO2 70.03 wt%, Al2O3 20.40 wt%, CaO 0.02 wt%, MgO 2.51 wt%, Fe2O3 3.56 wt%, TiO2 0.15 wt%, K2O 1.53 wt%, Na2O 0.71 wt%, loss on ignition 1.09 wt%.

[0080] The chemical composition of the bauxite is: SiO2 6.5 wt%, Al2O3 84.45 wt%, CaO 0.41 wt%, MgO 0.1 wt%, Fe2O3 2.27 wt%, TiO2 3.64 wt%, K2O 0.18 wt%, Na2O 0.01 wt%, loss on ignition 0.03 wt%.

[0081] The binder is selected as industrial dextrin.

[0082] 2. Mixing

[0083] The mixture of gold tailings slag, bauxite and binder is wet ball-milled with water, and the mass of water added accounts for 8% of the sum of the masses of the gold tailings slag, bauxite and binder mixture, and is ground to a particle size ≤ 5 μm; then drying treatment is carried out, the drying temperature is 108 °C, and the drying time is 9 h to obtain the first mixture. Industrial alumina and zirconia are added to the first mixture for dry ball-milling, the ball-milling time is 5 h, and it is ground to a particle size ≤ 3 μm to obtain the second mixture.

[0084] 3. Dry pressing

[0085] The second mixture is dry-pressed, and the pressure is 150 MPa

[0086] 4. Sintering

[0087] Then sintering is carried out. The sintering is heated to 1260 °C at a rate of 7 °C / min, held for 1.5 h, and finally heated to 1470 °C at a rate of 4 °C / min and held for 4.2 h, and finally cooled in the furnace to obtain the mullite refractory prepared from gold tailings slag as the raw material.

[0088] Performance testing

[0089] The performance of the mullite refractories prepared in Examples 1 to 4 is tested. The test indexes include the compressive strength, apparent porosity, bulk density and thermal shock stability of the mullite refractory, and the test results are shown in Table 1.

[0090] Table 1

[0091]

[0092] In the method for preparing the mullite refractory in the embodiment of the present invention, using gold tailings slag as the raw material, through a simple and feasible preparation method, the cheap gold tailings resources are converted into high-value mullite refractories with good comprehensive performance, thus realizing the development and value-added utilization of gold tailings slag in the field of refractories, which is beneficial to reducing the production cost of refractories and opening up a new way for the recycling of resources. Therefore, it is of great significance to use cheap gold tailings slag to reduce the cost of synthesizing mullite in the present invention.

[0093] The above content is a further detailed description of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is only limited to these descriptions. For those skilled in the technical field to which the present invention belongs, without departing from the concept of the present invention, several equivalent substitutions or obvious modifications can be made, and if the performance or use is the same, they should all be regarded as belonging to the protection scope of the present invention.

Claims

1. A method for preparing mullite refractory materials, characterized in that, It includes the following steps: S1. Mix 5 - 15 parts by weight of gold tailings slag, 30 - 45 parts by weight of bauxite and a binder, and grind them until the particle size is ≤5 μm to obtain a first mixture; wherein, wet ball milling is carried out with water added, and the mass of water added accounts for 5% - 15% of the total mass of the gold tailings slag, bauxite and binder mixture; after grinding, drying treatment is carried out, the drying temperature is 100 - 110 °C, and the drying time is 8 - 13 h; S2. Add 3 - 8 parts by weight of alumina and 6 - 10 parts by weight of zirconia to the first mixture and grind until the particle size is ≤3 μm to obtain a second mixture; S3. Dry - press the second mixture, and the pressure for dry - pressing is 60 - 200 Mpa; S4. After sintering, the mullite refractory material is obtained. The sintering includes heating to 1200 - 1300 °C at a rate of 3 - 8 °C / min, holding for 1 - 3 h, then heating to 1400 - 1500 °C at a rate of 3 - 6 °C / min, holding for 3 - 5 h, and then cooling with the furnace.

2. The method according to claim 1, characterized in that, The binder accounts for 1% of the total mass of the raw materials.

3. The method according to claim 2, characterized in that The binder is selected from one or more of industrial dextrin, sodium carboxymethyl cellulose or calcium lignosulfonate.

4. The method according to claim 1, characterized in that In step S2, dry ball milling is carried out, and the ball - milling time is 4 - 6 h.

5. A mullite refractory material, characterized in that, Prepared by the method according to any one of claims 1 to 4.

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