Red clay nickel ore rotary kiln firebrick, preparation method and application thereof

Abstract

The application provides a kind of firebrick for laterite nickel ore rotary kiln and its preparation method and application, it relates to the technical field of shaped refractory material.The firebrick for laterite nickel ore rotary kiln is mainly made of mixed granular material formed by calcium hexaluminate particles and fused zirconia corundum particles, mixed fine powder material formed by calcium hexaluminate fine powder, corundum fine powder, clay fine powder and zirconite fine powder, and binder and water;By the cooperation of the above raw materials, the firebrick for laterite nickel ore rotary kiln has the characteristics of high temperature mechanical strength, low thermal conductivity, good thermal shock resistance, strong anti-erosion and anti-permeation ability, improves the problem of insufficient high temperature mechanical properties, low anti-erosion and anti-permeation ability of existing firebrick for laterite nickel ore rotary kiln.In addition, the raw materials required by the application are widely available, easy to obtain, and have no toxic components, which is friendly to the environment.The application also provides a preparation method of the above-mentioned firebrick for laterite nickel ore rotary kiln, which has simple preparation process, energy saving and environmental protection.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of shaped refractory materials. Specifically, it relates to a kind of red clay nickel ore rotary kiln refractory brick and its preparation method and application. BACKGROUND

[0002] The red clay nickel ore rotary kiln is an important smelting equipment in the fire nickel smelting process. During calcination, the material in the kiln is heated and dehydrated, and by adjusting the reduction reaction process and the alkalinity and viscosity of the melt, the nickel-iron is directly reduced and the slag-iron is separated inside the rotary kiln. As can be seen, the red clay nickel ore rotary kiln is accompanied by large amount of slag, low viscosity of molten slag, high alkalinity fluctuation and other process characteristics under smelting conditions, thus putting forward strict requirements on the service performance of the kiln lining refractory material.

[0003] At present, the refractory materials for red clay nickel ore rotary kiln mainly include castables and shaped bricks, and relevant patent documents have also been reported. For example, the Chinese patent application with the application number 201910658415.0 and the invention name "Improved red clay nickel ore rotary kiln special castable and its manufacturing method" discloses a red clay nickel ore rotary kiln castable, the main raw materials of which are bauxite, fused mullite and South African chrome sand, etc. The distribution uniformity of the castable is improved by adjusting the particle size distribution, and the anti-erosion property is improved by using South African chrome sand. However, due to the influence of the change of the atmosphere in the red clay nickel ore rotary kiln, combined with the interfacial reaction between the high alkalinity molten slag and the castable, it is easy to form toxic Cr 6+ components, which causes environmental hazards, and this is also the disadvantage of chromium-containing refractory materials.

[0004] The Chinese patent application with the application number 201610316974.X and the invention name "Red clay nickel ore rotary kiln calcium titan-aluminate brick and its preparation method" discloses a red clay nickel ore rotary kiln fired brick, the main raw materials of which include titanium-iron slag and high-purity magnesia, and the micro-powder is used to promote sintering, on the one hand to improve the utilization rate of solid waste resources, and on the other hand to reduce the thermal conductivity of the material by in-situ reaction of the components. However, due to the complex composition and variable reaction of the multi-phase material system, the in-situ firing of calcium titan-aluminate brick is difficult to control. In addition, the red clay nickel ore rotary kiln belongs to a dynamic thermal equipment, and the kiln body generates obvious axial force during rotation, which also requires high temperature mechanical properties (reducing the glass phase content at high temperature) of the kiln lining brick.

[0005] The document "Development and Practice of Low Magnesia Conductivity Zirconia Brick for Rotary Kiln of Laterite Nickel Ore" (Pan Liuting, Ma Shulong. Ferroalloy, 2015, (3): pp19-42) reports the preparation of low magnesia conductivity zirconia brick using microporous magnesia-alumina synthetic material, fused magnesia-alumina spinel and zircon source fine powder, which effectively reduces the cylinder temperature and load of the rotary kiln, and achieves the purpose of energy saving and consumption reduction. Compared with magnesia-alumina spinel brick, the ZrO2 in the magnesia-alumina zirconia brick has poor wettability with the molten slag, which significantly improves the corrosion and penetration resistance. However, the use of microporous magnesia-alumina synthetic material reduces the mechanical strength of the kiln lining brick, weakens the high temperature mechanical properties of the kiln lining, and increases the apparent porosity of the material, which reduces the density of the material, which poses a hidden danger to the corrosion and penetration resistance of the kiln lining brick under the cyclic service condition.

[0006] Therefore, the present application is proposed. SUMMARY

[0007] The present application provides a kind of laterite nickel ore rotary kiln refractory brick and its preparation method and application, the laterite nickel ore rotary kiln refractory brick has the characteristics of high temperature mechanical strength, low thermal conductivity, good thermal shock resistance, strong corrosion resistance and penetration resistance.

[0008] In order to achieve the above purpose, the present application provides the following technical solutions:

[0009] The present application provides a kind of laterite nickel ore rotary kiln refractory brick, which is mainly made of mixed granular material, mixed fine powder material, binder and water;

[0010] The mixed granular material includes the following raw materials: calcium hexaluminate particles and fused zirconia corundum particles;

[0011] The mixed fine powder material includes the following raw materials: calcium hexaluminate fine powder, corundum fine powder, clay fine powder and zircon fine powder.

[0012] Further, in the above technical solution of the present application, the mass ratio of calcium hexaluminate particles and fused zirconia corundum particles in the mixed granular material is 100: (25-30).

[0013] Further, in the above technical solution of the present application, the particle size of the calcium hexaluminate particles is 0.5-8mm;

[0014] And / or, the main chemical composition and mass content of the calcium hexaluminate particles are: CaO 8-9wt%, Al2O3≥90wt%;

[0015] And / or, the particle size of the fused zirconia corundum particles is 0.1-5mm;

[0016] And / or, the main chemical composition and mass content of the fused zirconia corundum particles are: Al2O3 40-45wt%, ZrO2 45-50wt%.

[0017] Furthermore, based on the above-mentioned technical solution of the present invention, the mass ratio of calcium hexaaluminate fine powder, corundum fine powder, clay fine powder and zircon fine powder in the mixed fine powder is 100:(40-45):(4-6):(3-5).

[0018] Furthermore, based on the above-mentioned technical solution of the present invention, the particle size of the calcium hexaaluminate fine powder is 70-80 μm;

[0019] And / or, the main chemical composition and mass content of the calcium hexaaluminate fine powder are: CaO 8-9wt%, Al2O3 ≥90wt%;

[0020] And / or, the particle size of the corundum powder is 40-50 μm;

[0021] And / or, the main chemical composition and mass content of the corundum fine powder are: Al2O3≥99.5wt%, Na2O≤0.1wt%.

[0022] Furthermore, based on the above-mentioned technical solution of the present invention, the particle size of the clay powder is 50-60 μm;

[0023] And / or, the main chemical composition and mass content of the clay powder are: Al2O3 25-30wt%, SiO2 35-40wt%;

[0024] And / or, the particle size of the zircon fine powder is 60-70 μm;

[0025] And / or, the main chemical composition and mass content of the zircon fine powder are: ZrO2 62-65wt%, SiO2 32-33wt%.

[0026] Furthermore, based on the above-described technical solution of the present invention, the binder includes dextrin;

[0027] Preferably, the particle size of the dextrin is ≤40μm;

[0028] Preferably, the mass ratio of the mixed granules, mixed fine powder, binder and water is 100:(45-50):(3-5):(5-7).

[0029] This invention also provides a method for preparing refractory bricks for rotary kilns using laterite nickel ore, comprising the following steps:

[0030] (a) The mixture of mixed granules, mixed fine powder, binder and water is sealed and cured, then pressed into shape using a mold, and dried after demolding to obtain raw brick blanks;

[0031] (b) The raw brick blanks are fired to obtain refractory bricks for rotary kilns of laterite nickel ore.

[0032] Furthermore, based on the above technical solution of the present invention, in step (a), the temperature for sealing and curing is 20-25°C, and the time for sealing and curing is 8-10 hours;

[0033] And / or, in step (a), the pressing pressure is 60-80 MPa;

[0034] And / or, in step (a), the drying temperature is 100–110°C and the drying time is 10–12 h;

[0035] And / or, in step (b), the firing temperature is 1500-1600℃, and the holding time at the firing temperature is 4-5h.

[0036] The present invention also provides the application of the above-mentioned refractory bricks for laterite nickel ore rotary kilns or the refractory bricks for laterite nickel ore rotary kilns prepared by the above-mentioned preparation method in laterite nickel ore rotary kilns.

[0037] Compared with the prior art, the technical solution of the present invention has at least the following technical effects:

[0038] (1) This invention provides a refractory brick for rotary kilns of laterite nickel ore, mainly composed of a mixed granular material formed by calcium hexaaluminate particles and fused zirconium corundum particles, a mixed fine powder material formed by calcium hexaaluminate fine powder, corundum fine powder, clay fine powder and zircon fine powder, as well as a binder and water. Through the combination of the above raw materials, this refractory brick for rotary kilns of laterite nickel ore has the characteristics of high high-temperature mechanical strength, low thermal conductivity, good thermal shock resistance, and strong erosion and impermeability, thus improving the problems of insufficient high-temperature mechanical properties and low erosion and impermeability of existing refractory bricks for rotary kilns of laterite nickel ore. In addition, the raw materials required by this invention are widely available, easy to obtain, and contain no toxic components, making it environmentally friendly.

[0039] (2) The present invention provides a method for preparing the above-mentioned refractory bricks for rotary kilns of laterite nickel ore. The preparation process is simple, energy-saving and environmentally friendly, and has no special equipment requirements, which reduces the development cost of refractory bricks for rotary kilns of laterite nickel ore and is suitable for large-scale industrial production.

[0040] (3) This invention also provides the application of the above-mentioned refractory bricks for laterite nickel ore rotary kilns in laterite nickel ore rotary kilns. In view of the advantages of the above-mentioned refractory bricks for laterite nickel ore rotary kilns, they have good application prospects in laterite nickel ore rotary kilns. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions in the embodiments of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. Those skilled in the art should understand that the embodiments described are merely illustrative of the invention and should not be considered as specific limitations thereof. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention. Process parameters not specifically specified in the following embodiments are generally performed under conventional conditions.

[0042] The endpoints and any values ​​of the ranges disclosed in this invention are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this invention.

[0043] According to a first aspect of the present invention, a refractory brick for a rotary kiln of laterite nickel ore is provided, which is mainly made of mixed granular material, mixed fine powder, binder and water;

[0044] The mixed granular material includes the following raw materials: calcium hexaaluminate granules and fused zirconia corundum granules;

[0045] The mixed fine powder includes the following raw materials: calcium hexaaluminate fine powder, corundum fine powder, clay fine powder and zircon fine powder.

[0046] The refractory bricks for rotary kilns made from laterite nickel ore provided by this invention are mainly composed of a mixed granular material formed by calcium hexaaluminate particles and fused zirconium corundum particles, a mixed fine powder material formed by calcium hexaaluminate fine powder, corundum fine powder, clay fine powder and zircon fine powder, a binder and water. Calcium hexaaluminate with low thermal conductivity is selected as the raw material to reduce the thermal conductivity of the material system. Simultaneously, the in-situ sintering reaction of the calcium-aluminum-silicon ternary system is regulated to form anorthite, further reducing the thermal conductivity of the brick and achieving energy saving and consumption reduction in the kiln lining bricks. Clay is used as the binding system to provide a liquid phase environment at high temperatures, promoting the diffusion and mass transfer of components. The liquid phase promotes sintering and improves the mechanical strength of the material. At the same time, the calcination decomposition of zircon forms a free ZrO2 component that is resistant to erosion and penetration. Combined with the crystal transformation of the silicon source, this absorbs the thermal stress inside the brick body, effectively improving the thermal shock resistance of the kiln lining bricks. By combining various raw materials, the refractory bricks for rotary kilns using laterite nickel ore possess characteristics such as high high-temperature mechanical strength, low thermal conductivity, good thermal shock resistance, and strong resistance to erosion and permeation. Furthermore, the raw materials required for this invention are widely available, easily obtained, and contain no toxic components, making them environmentally friendly.

[0047] Further optimization of the particle size, chemical composition, or dosage of each raw material is needed.

[0048] As an optional embodiment of the present invention, the mass ratio of calcium hexaaluminate particles to fused zirconia corundum particles in the mixed granules is 100:(25-30), and typical but non-limiting mass ratios are 100:25, 100:26, 100:27, 100:28, 100:29 or 100:30, etc.

[0049] As an optional embodiment of the present invention, the particle size of the calcium hexaaluminate particles is 0.5 to 8 mm; typical but non-limiting particle sizes are 0.5 mm, 1 mm, 2 mm, 4 mm, 5 mm, 6 mm, 7 mm or 8 mm.

[0050] As an optional embodiment of the present invention, the main chemical components of the calcium hexaaluminate particles are: CaO content 8-9wt%, Al2O3 content ≥90wt%.

[0051] As an optional embodiment of the present invention, the particle size of the fused zirconia corundum particles is 0.1 to 5 mm; typical but non-limiting particle sizes are 0.1 mm, 0.5 mm, 1 mm, 2 mm, 4 mm or 5 mm, etc.

[0052] As an optional embodiment of the present invention, the chemical composition of the fused zirconia corundum particles is: Al2O3 content 40-45wt%, ZrO2 content 45-50wt%.

[0053] In one optional embodiment of the present invention, the mass ratio of calcium hexaaluminate fine powder, corundum fine powder, clay fine powder, and zircon fine powder in the mixed fine powder is 100:(40-45):(4-6):(3-5). Typical but non-limiting mass ratios are 100:40:4:3, 100:42:4:3, 100:45:4:3, 100:40:5:3, 100:40:6:3, 100:40:4:5, 100:42:5:4, 100:45:5:5, or 100:45:6:5, etc.

[0054] As an optional embodiment of the present invention, the particle size of the calcium hexaaluminate fine powder is 70-80 μm; typical but non-limiting particle sizes are 70 μm, 72 μm, 74 μm, 75 μm, 76 μm, 78 μm or 80 μm, etc.

[0055] As an optional embodiment of the present invention, the chemical composition of the calcium hexaaluminate fine powder is: CaO content 8-9wt%, Al2O3 content ≥90wt%;

[0056] As an optional embodiment of the present invention, the particle size of the corundum fine powder is 40-50 μm; typical but non-limiting particle sizes are 40 μm, 42 μm, 44 μm, 45 μm, 46 μm, 48 μm or 50 μm, etc.

[0057] As an optional embodiment of the present invention, the chemical composition of the corundum fine powder is: Al2O3 content ≥ 99.5 wt%, Na2O content ≤ 0.1 wt%.

[0058] As an optional embodiment of the present invention, the particle size of the clay powder is 50-60 μm; typical but non-limiting particle sizes are 50 μm, 52 μm, 54 μm, 55 μm, 56 μm, 58 μm or 60 μm, etc.

[0059] As an optional embodiment of the present invention, the chemical composition of the clay powder is: Al2O3 content 25-30wt%, SiO2 content 35-40wt%.

[0060] As an optional embodiment of the present invention, the particle size of the zircon fine powder is 60-70 μm; typical but non-limiting particle sizes are 60 μm, 62 μm, 64 μm, 65 μm, 66 μm, 68 μm or 70 μm, etc.

[0061] As an optional embodiment of the present invention, the chemical composition of the zircon fine powder is: ZrO2 content 62-65wt%, SiO2 content 32-33wt%.

[0062] By further defining the chemical composition and particle size of each raw material, the particle size distribution of the material is made to achieve close packing, thereby improving the tight bonding of the material system.

[0063] In one optional embodiment of the present invention, the binder includes dextrin. Using dextrin effectively improves the plasticity of the mixture while not introducing other impurities and causing pollution.

[0064] As an optional embodiment of the present invention, the particle size of the dextrin is ≤40μm, and typical but non-limiting particle sizes are 10μm, 15μm, 20μm, 25μm, 30μm, 35μm or 40μm, etc.

[0065] As an optional embodiment of the present invention, the mass ratio of the mixed granules, mixed fine powder, binder, and water is 100:(45-50):(3-5):(5-7). Typical but non-limiting mass ratios are 100:45:3:5, 100:48:3:5, 100:50:3:5, 100:45:4:5, 100:45:5:5, 100:45:5:7, 100:48:4:6, or 100:50:5:7, etc.

[0066] As an optional embodiment of the present invention, the apparent porosity of the refractory bricks used in rotary kilns for laterite nickel ore is measured to be 15.5%–16.2%, the compressive strength at room temperature is 75–82 MPa, the flexural strength at high temperature (1100℃) is 8.3–9.6 MPa, the thermal shock test (1100℃ water cooling) is ≥18 times, the thermal conductivity is 3.65–3.71 W / (m·K), and the erosion index of the static crucible method slag resistance test at 1400℃×3h is 1.6–2.2%.

[0067] Typical, but not limiting, apparent porosities are 15.5%, 15.6%, 15.8%, 16.0%, or 16.2%, etc., and typical, but not limiting, room temperature compressive strengths are 75 MPa, 76 MPa, 78 MPa, 80 MPa, or 82 MPa, etc. Typical, but not limiting, high-temperature flexural strengths (1100℃) are 8.3 MPa, 8.5 MPa, 8.6 MPa, 8.8 MPa, 9.0 MPa, 9.2 MPa, 9.4 MPa, 9.5 MPa, or 9.6 MPa, etc. Typical but non-limiting thermal shock tests (1100℃ water cooling) are 18, 20, 22, 24, or 25 times, etc., and typical but non-limiting thermal conductivity is 3.65W / (m·K), 3.66W / (m·K), 3.68W / (m·K), 3.70W / (m·K), or 3.71W / (m·K), etc., and typical but non-limiting erosion index of static crucible method slag resistance test at 1400℃×3h is 1.6%, 1.7%, 1.8%, 1.9%, 2.0%, 2.1%, or 2.2%, etc.

[0068] According to a second aspect of the present invention, a method for preparing refractory bricks for laterite nickel ore rotary kilns is also provided, comprising the following steps:

[0069] (a) The mixture of mixed granules, mixed fine powder, binder and water is sealed and cured, then pressed into shape using a mold, and dried after demolding to obtain raw brick blanks;

[0070] (b) The raw brick blanks are fired to obtain refractory bricks for rotary kilns of laterite nickel ore.

[0071] The preparation process of the refractory bricks for rotary kilns of laterite nickel ore is simple, requires no special equipment, reduces the development cost of refractory bricks for rotary kilns of laterite nickel ore, and is suitable for large-scale industrial production.

[0072] The preparation of the mixed granules in step (a) can be carried out using conventional mixing methods.

[0073] As an optional embodiment of the present invention, calcium aluminate particles and fused zirconia corundum particles are mixed in a certain proportion for 3 to 5 minutes (e.g., 3 minutes, 4 minutes or 5 minutes) to obtain mixed granular material.

[0074] As an optional embodiment of the present invention, fine powders of calcium hexaaluminate, corundum, clay, and zircon are mixed in proportion for 25 to 40 minutes (e.g., 25 minutes, 28 minutes, 30 minutes, 32 minutes, 35 minutes, 38 minutes, or 40 minutes) to obtain a mixed fine powder.

[0075] In one optional embodiment of the present invention, in step (a), the temperature for sealing and curing is 20–25°C, and the time for sealing and curing is 8–10 hours. Typical but non-limiting sealing and curing temperatures are 20°C, 22°C, 24°C, or 25°C, and typical but non-limiting sealing and curing times are 8 hours, 9 hours, or 10 hours, etc.

[0076] As an optional embodiment of the present invention, in step (a), the pressing pressure is 60-80 MPa. Typical but non-limiting pressures are 60 MPa, 62 MPa, 64 MPa, 65 MPa, 68 MPa, 70 MPa, 72 MPa, 74 MPa, 75 MPa, 78 MPa, or 80 MPa, etc.

[0077] As an optional embodiment of the present invention, in step (a), the drying temperature is 100-110°C and the drying time is 10-12h; typical but non-limiting drying temperatures are 101°C, 102°C, 104°C, 105°C, 106°C, 108°C or 110°C and any range between any two points, and typical but non-limiting drying times are 10h, 11h or 12h.

[0078] In one optional embodiment of the present invention, in step (b), the firing temperature is 1500–1600°C, and the holding time at the firing temperature is 4–5 hours. Typical but non-limiting firing temperatures include 1500°C, 1520°C, 1540°C, 1550°C, 1560°C, 1580°C, or 1600°C, etc., and typical but non-limiting holding times include 4 hours, 4.5 hours, or 5.0 hours, etc.

[0079] By further limiting the above process parameters, the decomposition of zircon is made complete, and the sintering reaction of the material is fully carried out.

[0080] According to a third aspect of the invention, the invention also provides the application of refractory bricks for laterite nickel ore rotary kilns in laterite nickel ore rotary kilns.

[0081] Given the advantages of the refractory bricks used in rotary kilns for laterite nickel ore, they have good application prospects in laterite nickel ore rotary kilns and can effectively improve the service life of laterite nickel ore rotary kilns.

[0082] The present invention will now be described in further detail with reference to specific embodiments and comparative examples. The particle size and composition of the raw materials in the embodiments and comparative examples are explained below:

[0083] The particle size of calcium hexaaluminate granules is 0.5-8 mm. The main chemical components of calcium hexaaluminate granules are: CaO content 8-9 wt%, Al2O3 content ≥90 wt%.

[0084] The particle size of the fused zirconia corundum particles is 0.1-5 mm, and the main chemical composition of the fused zirconia corundum particles is: Al2O3 content 40-45 wt%, ZrO2 content 45-50 wt%.

[0085] The particle size of calcium hexaaluminate fine powder is 70-80 μm. The main chemical components of calcium hexaaluminate fine powder are: CaO content 8-9 wt%, Al2O3 content ≥90 wt%.

[0086] The particle size of corundum fine powder is 40-50 μm, and the main chemical components of corundum fine powder are: Al2O3 content ≥99.5wt%, Na2O content ≤0.1wt%.

[0087] The particle size of the clay powder is 50-60 μm, and the main chemical components of the clay powder are: Al2O3 content 25-30 wt%, SiO2 content 35-40 wt%.

[0088] The particle size of zircon fine powder is 60-70 μm, and the main chemical composition of zircon fine powder is: ZrO2 content 62-65 wt%, SiO2 content 32-33 wt%.

[0089] The yellow dextrin is of industrial purity, and its particle size is 10–40 μm.

[0090] The particle size of magnesia is 0.5-8mm, and the main chemical composition of magnesia is: MgO content ≥97wt%.

[0091] The particle size of the magnesia fine powder is 70-80 μm, and the main chemical composition of the magnesia fine powder is: MgO content ≥97wt%.

[0092] The particle size of the silicon micro powder is 50-60 μm, and the main chemical composition of the silicon micro powder is: SiO2 content ≥95wt%.

[0093] The particle size of mullite fine powder is 60-70 μm, and the main chemical components of mullite fine powder are: Al2O3 content 70-72 wt%, SiO2 content 27-28 wt%.

[0094] Example 1

[0095] This embodiment provides a refractory brick for a rotary kiln of laterite nickel ore, which is mainly made of mixed granular material, mixed fine powder, binder xanthus dextrin and water;

[0096] The mixed granular material includes the following raw materials: calcium hexaaluminate granules and fused zirconia corundum granules, with a mass ratio of calcium hexaaluminate granules to fused zirconia corundum granules of 100:25.

[0097] The mixed fine powder includes the following raw materials: calcium hexaaluminate fine powder, corundum fine powder, clay fine powder and zircon fine powder, with the mass ratio of calcium hexaaluminate fine powder, corundum fine powder, clay fine powder and zircon fine powder being 100:42:4:4.

[0098] The mass ratio of the mixed granules, mixed fine powder, binder dextrin, and water is 100:48:5:7.

[0099] The preparation method of refractory bricks for rotary kilns of laterite nickel ore in this embodiment includes the following steps:

[0100] (a) Mix calcium aluminate particles and fused zirconium corundum particles in a certain proportion for 3 minutes to obtain mixed granular material;

[0101] (b) Mix calcium hexaaluminate fine powder, corundum fine powder, clay fine powder and zircon fine powder for 30 minutes to obtain a mixed fine powder material;

[0102] (c) Mix the mixed granules, mixed fine powder, binder dextrin and water in a mixer for 12 minutes to obtain the mixture;

[0103] (d) After sealing and curing the mixture at 22°C for 8 hours, it is added to a mold and pressed at 70MPa. After demolding, it is dried at 100°C for 10 hours to obtain green bricks.

[0104] (e) The green bricks are transferred to a tunnel kiln and kept at 1600°C for 4 hours to produce refractory bricks for rotary kilns of laterite nickel ore.

[0105] Example 2

[0106] This embodiment provides a refractory brick for a rotary kiln of laterite nickel ore, which is mainly made of mixed granular material, mixed fine powder, binder xanthus dextrin and water;

[0107] The mixed granular material includes the following raw materials: calcium hexaaluminate granules and fused zirconia corundum granules, with a mass ratio of calcium hexaaluminate granules to fused zirconia corundum granules of 100:28.

[0108] The mixed fine powder includes the following raw materials: calcium hexaaluminate fine powder, corundum fine powder, clay fine powder and zircon fine powder, with the mass ratio of calcium hexaaluminate fine powder, corundum fine powder, clay fine powder and zircon fine powder being 100:45:6:3.

[0109] The mass ratio of the mixed granules, mixed fine powder, binder dextrin, and water is 100:46:3:7.

[0110] The preparation method of refractory bricks for rotary kilns of laterite nickel ore in this embodiment includes the following steps:

[0111] (a) Mix calcium aluminate particles and fused zirconium corundum particles in a certain proportion for 5 minutes to obtain mixed granular material;

[0112] (b) Mix calcium hexaaluminate fine powder, corundum fine powder, clay fine powder and zircon fine powder in proportion for 35 minutes to obtain mixed fine powder material;

[0113] (c) Mix the mixed granules, mixed fine powder, binder dextrin and water in a mixer in proportion and mix for 15 minutes to obtain the mixture.

[0114] (d) After sealing and curing the mixture at 25°C for 8 hours, it is added to a mold and pressed at 75MPa. After demolding, it is dried at 100°C for 10 hours to obtain green bricks.

[0115] (e) The green bricks are transferred to a tunnel kiln and kept at 1500°C for 5 hours to produce refractory bricks for rotary kilns of laterite nickel ore.

[0116] Example 3

[0117] This embodiment provides a refractory brick for a rotary kiln of laterite nickel ore, which is mainly made of mixed granular material, mixed fine powder, binder xanthus dextrin and water;

[0118] The mixed granular material includes the following raw materials: calcium hexaaluminate granules and fused zirconia corundum granules, with a mass ratio of calcium hexaaluminate granules to fused zirconia corundum granules of 100:26.

[0119] The mixed fine powder includes the following raw materials: calcium hexaaluminate fine powder, corundum fine powder, clay fine powder and zircon fine powder, with the mass ratio of calcium hexaaluminate fine powder, corundum fine powder, clay fine powder and zircon fine powder being 100:43:5:3;

[0120] The mass ratio of the mixed granules, mixed fine powder, binder dextrin, and water is 100:50:4:6.

[0121] The preparation method of refractory bricks for rotary kilns of laterite nickel ore in this embodiment includes the following steps:

[0122] (a) Mix calcium aluminate particles and fused zirconium corundum particles in a certain proportion for 4 minutes to obtain mixed granular material;

[0123] (b) Mix calcium hexaaluminate fine powder, corundum fine powder, clay fine powder and zircon fine powder in proportion for 40 minutes to obtain mixed fine powder material;

[0124] (c) Mix the mixed granules, mixed fine powder, binder dextrin and water in a mixer in proportion and mix for 15 minutes to obtain the mixture.

[0125] (d) After sealing and curing the mixture at 23°C for 10 hours, it is added to a mold and pressed at 70MPa. After demolding, it is dried at 110°C for 12 hours to obtain green bricks.

[0126] (e) The green bricks are transferred to a tunnel kiln and kept at 1550°C for 4 hours to produce refractory bricks for rotary kilns of laterite nickel ore.

[0127] Example 4

[0128] This embodiment provides a refractory brick for a rotary kiln of laterite nickel ore and its preparation method. Except for replacing the type of binder with yellow dextrin and using pulp waste liquor, with a pH of 6.5-7, the other raw materials, types and preparation methods are the same as in Example 1.

[0129] Example 5

[0130] This embodiment provides a refractory brick for a rotary kiln of laterite nickel ore and its preparation method. Except for replacing the type of binder with dextrin instead of aluminum dihydrogen phosphate solution with a mass fraction of 3% and a pH of 9-10, the other raw materials, types and preparation methods are the same as in Example 2.

[0131] Example 6

[0132] This embodiment provides a refractory brick for a rotary kiln of laterite nickel ore and its preparation method. Except for adjusting the mass ratio of calcium hexaaluminate particles and fused zirconium corundum particles in the mixed granular material from 100:25 to 100:40, the other raw materials, types and preparation methods are the same as in Example 2.

[0133] Example 7

[0134] This embodiment provides a refractory brick for a rotary kiln of laterite nickel ore and its preparation method. Except for adjusting the mass ratio of calcium hexaaluminate fine powder, corundum fine powder, clay fine powder and zircon fine powder in the mixed fine powder from 100:45:6:3 to 100:45:3:3, the other raw materials, types and preparation methods are the same as in Example 2.

[0135] Comparative Example 1

[0136] This comparative example provides a refractory brick for a rotary kiln of laterite nickel ore and its preparation method. Except that the calcium hexaaluminate particles in the mixed granular material are replaced with an equal amount of magnesia particles, and the calcium hexaaluminate fine powder in the mixed fine powder is replaced with an equal amount of magnesia fine powder, the other raw materials, types and preparation methods are the same as in Example 2.

[0137] Comparative Example 2

[0138] This comparative example provides a refractory brick for a rotary kiln made of laterite nickel ore and its preparation method. Except that no clay powder is added to the mixed fine powder, the other raw materials, types and preparation methods are the same as in Example 2.

[0139] Comparative Example 3

[0140] This comparative example provides a refractory brick for a laterite nickel ore rotary kiln and its preparation method. Except for replacing the clay powder in the mixed fine powder with an equal amount of silica powder, the other raw materials, types and preparation methods are the same as in Example 2.

[0141] Comparative Example 4

[0142] This comparative example provides a refractory brick for a rotary kiln made of laterite nickel ore and its preparation method. Except for the absence of zircon powder in the mixed fine powder, the raw materials, types and preparation methods are the same as in Example 2.

[0143] Comparative Example 5

[0144] This comparative example provides a refractory brick for a rotary kiln of laterite nickel ore and its preparation method. Except for replacing the zircon fine powder in the mixed fine powder with an equal amount of mullite fine powder, the other raw materials, types and preparation methods are the same as in Example 2.

[0145] To further verify the technical effects of the above embodiments and comparative examples, the following experimental examples are provided.

[0146] Experimental Example 1

[0147] The performance of the refractory bricks for rotary kilns using laterite nickel ore provided in each embodiment and comparative example was tested. Specifically, apparent porosity was tested according to GB / T 2997-2015, room temperature compressive strength according to GB / T5072-2008, high-temperature flexural strength (1100℃) according to GB / T3002-2017, the number of thermal shock tests (1100℃ water-cooled) according to GB / T 30873-2014, thermal conductivity according to GB / T36133-2018, and the erosion index of the static crucible method slag resistance test according to GB / T8931-2007. Specific results are shown in Table 1.

[0148] Table 1

[0149]

[0150] As shown in Table 1, the experimental data above indicate that the binder has a significant impact on the bonding performance and mechanical strength of the material. Yellow dextrin, by not introducing other impurity components, effectively ensures the high-temperature mechanical properties of the material. The decomposition and thermal stress absorption of components such as zircon can improve the thermal shock resistance of the material, while also improving the room temperature compressive strength, high temperature flexural strength, thermal conductivity, and corrosion resistance. The liquid phase medium environment of clay powder is superior to that of alternative products such as silicon micropowder and mullite powder, which is mainly due to the overall sintering of the aluminum-silicon components.

[0151] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A refractory brick for a rotary kiln in laterite nickel ore production, characterized in that, It is made from mixed granules, mixed fine powders, dextrin, and water; The mass ratio of the mixed granules, mixed fine powder, dextrin and water is 100:(45~50):(3~5):(5~7); The mixed granular material is composed of the following raw materials: calcium hexaaluminate granules and fused zirconium corundum granules; The mixed fine powder is composed of the following raw materials: calcium hexaaluminate fine powder, corundum fine powder, clay fine powder and zircon fine powder; The particle size of the calcium hexaaluminate particles is 0.5~8mm; the particle size of the fused zirconium corundum particles is 0.1~5mm. The fine calcium hexaaluminate powder has a particle size of 70-80 μm; the fine corundum powder has a particle size of 40-50 μm; the fine clay powder has a particle size of 50-60 μm; and the fine zircon powder has a particle size of 60-70 μm. In the mixed granular material, the mass ratio of calcium hexaaluminate particles to fused zirconia corundum particles is 100:(25~30). In the mixed fine powder, the mass ratio of calcium hexaaluminate fine powder, corundum fine powder, clay fine powder and zircon fine powder is 100: (40~45): (4~6): (3~5).

2. The refractory brick for rotary kilns of laterite nickel ore according to claim 1, characterized in that, The main chemical composition and mass content of the calcium hexaaluminate particles are: CaO 8~9wt%, Al2O3 ≥90wt%; And / or, the main chemical composition and mass content of the fused zirconia corundum particles are: Al2O3 40~45wt%, ZrO2 45~50wt%.

3. The refractory brick for rotary kilns of laterite nickel ore according to claim 1, characterized in that, The main chemical components and mass content of the calcium hexaaluminate fine powder are: CaO 8~9wt%, Al2O3 ≥90wt%; And / or, the main chemical composition and mass content of the corundum fine powder are: Al2O3 ≥ 99.5wt%, Na2O ≤ 0.1wt%.

4. The refractory brick for rotary kilns of laterite nickel ore according to claim 1, characterized in that, The main chemical components and mass content of the clay powder are: Al2O3 25~30wt%, SiO2 35~40wt%; And / or, the main chemical composition and mass content of the zircon fine powder are: ZrO2 62~65wt%, SiO2 32~33wt%.

5. The refractory brick for rotary kilns of laterite nickel ore according to any one of claims 1-4, characterized in that, The particle size of the dextrin is ≤40μm.

6. The method for preparing refractory bricks for rotary kilns of laterite nickel ore according to any one of claims 1-5, characterized in that, Includes the following steps: (a) The mixture of mixed granules, mixed fine powder, binder and water is sealed and cured, then pressed into shape using a mold, and dried after demolding to obtain raw brick blanks; (b) The raw brick blanks are fired to obtain refractory bricks for rotary kilns of laterite nickel ore.

7. The method for preparing refractory bricks for rotary kilns of laterite nickel ore according to claim 6, characterized in that, In step (a), the temperature for sealing and curing is 20~25℃, and the time for sealing and curing is 8~10h; And / or, in step (a), the pressing pressure is 60~80 MPa; And / or, in step (a), the drying temperature is 100~110℃ and the drying time is 10~12h; And / or, in step (b), the firing temperature is 1500~1600℃, and the holding time at the firing temperature is 4~5h.

8. The application of the refractory bricks for laterite nickel ore rotary kilns as described in any one of claims 1-5, or the refractory bricks for laterite nickel ore rotary kilns prepared by the preparation method described in claim 6 or 7, in laterite nickel ore rotary kilns.

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