Foamed ceramic material based on low-silica high-calcium type iron tailings and method for preparing same

Abstract

The application provides a foamed ceramic material based on low-silicon high-calcium type iron tailings, and raw materials include, in percentage by weight, 20-60wt% of low-silicon high-calcium type iron tailings, 24-60wt% of barren material, 15-35wt% of plastic material, and 0.1-0.5wt% of foaming agent; and the application also provides a preparation method of the foamed ceramic material, which comprises the following steps: S1, mechanically dry mixing after fine grinding of the raw materials; S2, adding water to disperse and mix uniformly to obtain slurry, and drying and forming the slurry to obtain a blank; and S3, sintering the blank, and cutting after cooling to obtain the foamed ceramic material. In the application, the high-calcium type iron tailings is used as a flux material, which can completely replace feldspar and other fluxing materials to reduce production cost, reduce the amount of foaming agent, and greatly reduce the sintering temperature, and can solve the problems of resource utilization of large-scale mining waste and high value of products by cooperating with other solid waste materials.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of porous ceramic materials, and particularly relates to a foamed ceramic material based on low-silicon high-calcium iron tailings and a preparation method thereof. BACKGROUND

[0002] Foamed ceramic is a kind of porous ceramic material, which is obtained by adding a foaming agent into ceramic slurry and high-temperature sintering to obtain a closed-cell lightweight thermal insulation and sound insulation material with good refractory performance and low thermal conductivity, and is commonly used in the field of building for the production of large fireproof sound-absorbing walls such as house partitions, soundstages and theaters.

[0003] Iron tailings are waste materials from iron ore beneficiation. Depending on the production location, the composition of the iron tailings is complex and variable, and the mineral phase composition is rich. Depending on the type, the iron tailings can be classified into high-calcium type, high-aluminum type, high-calcium magnesium type, low-calcium silicon aluminum type, and multi-metal type. The iron tailings contain elements such as sodium, iron, sulfur, and phosphorus. Depending on the composition, the secondary utilization approaches are also quite different.

[0004] Currently, the foamed ceramic based on iron tailings commonly used in China is prepared by adding clay, kaolin, porcelain stone and other high-silicon aluminum materials. The iron tailings serve as the source of aluminosilicate framework, and a certain amount of feldspar, waste glass and other solubility materials are required to be used to sinter the foamed ceramic. The sintering temperature is high (1150-1200℃), the process flow is complex, the solid waste utilization interval is narrow, and the mechanical properties of the material are insufficient, which makes the economic effect and performance advantage of the product too low.

[0005] Based on the defects of the prior art, the present application is proposed. SUMMARY

[0006] The present application aims to overcome the defects of the prior art and provides a foamed ceramic material based on low-silicon high-calcium iron tailings and a preparation method thereof.

[0007] The present application provides the following technical solutions:

[0008] The present application provides a foamed ceramic material based on low-silicon high-calcium iron tailings. The raw materials include, by weight percentage, 20-60wt% of low-silicon high-calcium iron tailings, 24-60wt% of barren material, 15-35wt% of plastic material, and 0.1-0.5wt% of foaming agent.

[0009] The low-silicon high-calcium iron tailings used in the present application have a low silicon content and cannot be used as a silicon source for the silicate framework. The calcite contained in the low-silicon high-calcium iron tailings can be decomposed to form calcium oxide at high temperatures, which not only reduces the liquid phase generation temperature, but also reacts with silicon dioxide to form calcium feldspar (the main ceramic crystal phase).

[0010] The silicon carbide foaming agent generates carbon dioxide bubbles and silicon dioxide at the same time, the silicon dioxide film layer can wrap the silicon carbide particles to prevent the reaction from occurring, but the iron tailings can react with the silicon dioxide film layer to improve the gas release reaction efficiency of the silicon carbide; meanwhile, the iron tailings have a certain loss on ignition, which is easier to generate micropores, so that the amount of foaming agent can be effectively reduced, and the bulk density of the sample can be reduced. Compared with feldspar, the fluxing ability of the same amount of iron tailings is obviously stronger than that of feldspar, and the sintering temperature can be reduced by 100-150 DEG C, and the sintering temperature of the present application is 990-1050 DEG C. Compared with waste glass, the proportion of iron tailings that can be used in the formula is larger, and the waste resource rate is improved.

[0011] Further, the said lean material is high-silica material, including quartz powder, fly ash.

[0012] Further, the said plastic material is clay mineral, including kaolin, bentonite.

[0013] Further, the said low-silicon high-calcium type iron tailings composition includes 8-20wt% SiO2, 2-8wt% Al2O3, 20-35wt% CaO, 1-3wt% MgO, 17-30wt% Fe2O3 and 15-30% loss on ignition.

[0014] Further, the said plastic material composition includes 30-55wt% SiO2, 40-70wt% Al2O3 and the balance of calcium, magnesium and iron oxides.

[0015] Further, the said lean material composition includes 65-99wt% SiO2, 0-40wt% Al2O3 and the balance of calcium, magnesium and iron oxides.

[0016] The present application also provides a preparation method of the above-mentioned foamed ceramic material, comprising the following steps:

[0017] S1, the raw materials are finely ground and mechanically mixed;

[0018] S2, adding water to disperse and mix uniformly to obtain a slurry, and the slurry is dried and formed to obtain a blank;

[0019] S3, the blank is sintered, and after cooling, it is cut to obtain the foamed ceramic material.

[0020] Further, in step S1, the fineness of the lean material, the plastic material and the low-silicon high-calcium type iron tailings after grinding is below 200 mesh, and the foaming agent is silicon carbide, and the fineness of the silicon carbide is between 325 mesh and 1000 mesh.

[0021] If the fineness of the raw material is too low, it will waste energy, and the high specific surface area will increase the difficulty of mixing. When the fineness of the finely ground raw material is below 200 mesh, the dry mixing dispersion is relatively uniform, which helps to improve the strength of the green body. The greater the fineness of the silicon carbide, the more uniform the pore distribution during foaming. In the present application, the fineness of the silicon carbide is between 325 mesh and 1000 mesh.

[0022] Further, in step S1, the raw materials in mechanical dry mixing are stirred at a speed of 5-20 r / s for 30-60 s to achieve a fully mixed state.

[0023] Further, in step S2, the drying method is natural drying and heating drying. When the solid phase content is greater than 65%, natural drying is used, and when the environmental temperature is 20±5℃, the drying time is 16-24 h. When the solid phase content is below 65%, high-temperature drying is used, the drying temperature is 60-90℃, and the drying time is 4-16 h.

[0024] Further, in step S3, the firing temperature is 990-1050℃, the heating rate is 10℃ / min between 0-400℃, the heating rate is 5-7℃ / min between 400-800℃, the heating rate is 3-4℃ / min between 800-1000℃, the heating rate is 3℃ / min from 1000℃ to the firing temperature, the holding time is 5-10 min, and the fired product is naturally cooled after heating. Air circulation is maintained throughout the heating process.

[0025] The present application uses low-silicon high-calcium type iron tailings as flux material, which can completely replace feldspar, waste glass and other fluxing materials to reduce production cost, reduce the amount of foaming agent, and significantly reduce the firing temperature. Combined with other solid waste materials, the problem of resource utilization and high value of bulk mining waste can be solved.

[0026] The present application has the following beneficial effects:

[0027] 1. The present application uses low-silicon high-calcium type iron tailings with strong fluxing effect to replace feldspar as fluxing raw material. Since it does not serve as a silicon source, it is more flexible to adjust the formula when facing different product pore requirements. By changing the amount, the liquid phase viscosity at a certain firing temperature can be increased or decreased, which indirectly controls the size of the pores. It can also be widely used in a variety of solid waste, and significantly reduce production energy consumption, realize green, low carbon, energy saving and emission reduction production.

[0028] 2. The present application is beneficial to improve the limitations of conventional iron tailings as foaming ceramic materials. The loss on ignition component of iron tailings can act as a pore former, and the rich iron oxide and alkali metal can increase the reaction rate of silicon carbide. The two can effectively reduce the amount of foaming agent. The calcium oxide produced by the decomposition of calcite (CaCO3) contained in the iron tailings can reduce the sintering temperature and reduce the production cost.

[0029] 3、The application is beneficial to improve the secondary resource utilization rate of mining solid waste, accelerate the development of high value-added industry, solve the pollution of mining solid waste to the ecological environment, reduce the economic loss caused by tailings pond construction and land filling, develop a new way of innovative product for building material industry, reduce the raw material cost, optimize the process route, and greatly increase the economic benefit of enterprises. BRIEF DESCRIPTION OF DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained without creative labor on the basis of these drawings.

[0031] Figure 1 The physical map of the foamed ceramic material prepared in Example 1 of the present application;

[0032] Figure 2 The pore appearance of the foamed ceramic material prepared in Example 1 of the present application;

[0033] Figure 3 The XRD pattern of the foamed ceramic material prepared in the present application. DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments of the present application will be described clearly and completely in the following with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0035] The present application provides a foamed ceramic material based on low-silicon high-calcium type iron tailings. The raw materials include, by weight percentage, 20-60wt% of low-silicon high-calcium type iron tailings, 24-60wt% of barren material, 15-35wt% of plastic material, and 0.1-0.5wt% of foaming agent.

[0036] In specific embodiments, the foaming agent is silicon carbide, and the firing temperature is 990-1050℃.

[0037] In specific embodiments, the barren material is high-silicon material, including quartz powder and fly ash.

[0038] In specific embodiments, the plastic material is clay mineral, including kaolin and bentonite.

[0039] The high calcium type iron tailings ingredient comprises 8-20 wt% SiO2, 2-8 wt% Al2O3, 20-35 wt% CaO, 1-3 wt% MgO, 17-30 wt% Fe2O3 and 15-30 wt% loss on ignition by weight.

[0040] The plastic material ingredient comprises 30-55 wt% SiO2, 40-70 wt% Al2O3 and the balance of calcium, magnesium and iron oxides by weight.

[0041] The infertile material ingredient comprises 65-99 wt% SiO2, 0-40 wt% Al2O3 and the balance of calcium, magnesium and iron oxides by weight.

[0042] The embodiment of the present application also provides a method for preparing a foamed ceramic material from low-silicon high calcium type iron tailings, comprising the following steps:

[0043] S1, mechanically dry mixing the raw materials after fine grinding;

[0044] S2, adding water to disperse and mix uniformly to obtain a slurry, and drying the slurry to form a blank;

[0045] S3, sintering the blank, and cutting after cooling to obtain a foamed ceramic material.

[0046] In specific embodiments, in step S1, the fineness of the infertile material, the plastic material and the low-silicon high calcium type iron tailings after fine grinding is below 200 mesh, the foaming agent is silicon carbide, and the fineness of the silicon carbide is between 325 mesh and 1000 mesh.

[0047] In specific embodiments, in step S1, the raw materials are fully mixed after stirring at a speed of 5-20 r / s for 30-60 s in the mechanical dry mixing.

[0048] In specific embodiments, the drying method is natural drying and heating drying, and when the solid phase content is greater than 65%, the natural drying is used, and when the ambient temperature is 20±5℃, the drying time is 16-24 h; when the solid phase content is below 65%, the high temperature drying is used, the drying temperature is 60-90℃, and the drying time is 4-16 h.

[0049] In specific embodiments, the sintering temperature is 990-1050℃, the heating rate is 10℃ / min between 0-400℃, the heating rate is 5-7℃ / min between 400-800℃, the heating rate is 3-4℃ / min between 800-1000℃, the heating rate is 3℃ / min from 1000℃ to the sintering temperature, the holding time is 5-10 min, and the product is naturally cooled after heating; the air is circulated throughout the heating process.

[0050] The present application is further illustrated by the following specific embodiments:

[0051] The chemical composition of the low-silicon high-calcium type iron tailings used in the embodiments of the present application is shown in the following table:

[0052] Chemical composition SiO2 Al2O3 CaO MgO Fe2O3 LOI Percentage / % 8～20 2～8 20～35 1～3 17～30 15～30

[0053] The iron tailings come from Changyang region in Hubei Province, and are beneficiation tailings of oolitic hematite.

[0054] The chemical composition of the kaolin used in the embodiments of the present application is shown in the following table:

[0055] Chemical composition SiO2 Al2O3 CaO MgO Fe2O3 LOI Percentage / % 30～55 40～68 0～1 0～2 0～2 0～1

[0056] The chemical composition of the quartz used in the embodiments of the present application is shown in the following table:

[0057] Chemical composition SiO2 Al2O3 CaO MgO Fe2O3 LOI Percentage / % 99 0～1 0～1 0～1 0～1 0

[0058] Embodiment 1

[0059] The present embodiment provides a foamed ceramic material based on low-silicon high-calcium type iron tailings, and the raw materials include low-silicon high-calcium type iron tailings 39.88wt%, kaolin 19.94wt%, quartz 39.88wt%, and silicon carbide 0.3wt% by weight percentage.

[0060] The preparation process is as follows:

[0061] 1. After the raw materials are finely ground, mechanical dry mixing is performed for 1 min;

[0062] 2. Water is added and uniformly dispersed to obtain a slurry, and the solid content of the slurry is 63%. The slurry is dried at 80℃ for 8h to form a green body;

[0063] 3. The green body is placed in a resistance furnace, and the sintering is performed in the whole process under the condition of air circulation. The heating rate is 10℃ / min between 0-400℃, 5-7℃ / min between 400-800℃, 3-4℃ / min between 800-1000℃, and the temperature is kept at 1000℃ for 5 min to obtain the foamed ceramic.

[0064] Embodiment 2

[0065] The present embodiment provides a foamed ceramic material based on low-silicon high-calcium type iron tailings, and the raw materials include low-silicon high-calcium type iron tailings 29.92wt%, fly ash 26.91wt%, kaolin 22.93wt%, quartz 19.94wt%, and silicon carbide 0.3wt% by weight percentage.

[0066] The preparation process is as follows:

[0067] 1. After the raw materials are finely ground, mechanical dry mixing is performed for 1 min;

[0068] 2, add water and mix to obtain slurry, the solid content of the slurry is 66%, and the slurry is dried at 80℃ for 12h to form a green body;

[0069] 3, place the green body in a resistance furnace, and sinter the green body in the air flow, the heating rate is 10℃ / min between 0-400℃, 5-7℃ / min between 400-800℃, 3-4℃ / min between 800-1000℃, 3℃ / min between 1000-1050℃, and keep 1050℃ for 5min to obtain the foamed ceramic.

[0070] Example 3

[0071] The example provides a foamed ceramic material based on low-silicon high-calcium type iron tailings, the raw materials include low-silicon high-calcium type iron tailings 44.88wt%, kaolin 17.94wt%, quartz 36.88wt%, and silicon carbide 0.3wt%.

[0072] The preparation process is as follows:

[0073] 1, mechanically dry-mix the raw materials after fine grinding for 1min;

[0074] 2, add water and mix to obtain slurry, the solid content of the slurry is 60%, and the slurry is dried at 60℃ for 12h to form a green body;

[0075] 3, place the green body in a resistance furnace, and sinter the green body in the air flow, the heating rate is 10℃ / min between 0-400℃, 5-7℃ / min between 400-800℃, 3-4℃ / min between 800-990℃, and keep 990℃ for 5min to obtain the foamed ceramic.

[0076] Example 4

[0077] The example provides a foamed ceramic material based on low-silicon high-calcium type iron tailings, the raw materials include low-silicon high-calcium type iron tailings 39.92wt%, kaolin 19.96wt%, quartz 39.92wt%, and silicon carbide 0.2wt%.

[0078] The preparation process is as follows:

[0079] 1, mechanically dry-mix the raw materials after fine grinding for 1min;

[0080] 2, add water and mix to obtain slurry, the solid content of the slurry is 60%, and the slurry is dried at 60℃ for 12h to form a green body;

[0081] 3. The embryo body is placed in the resistance furnace, the whole process is sintered under the condition of keeping air circulation, the temperature rising rate is 10 DEG C / min between 0-400 DEG C, 5-7 DEG C / min between 400-800 DEG C, 3-4 DEG C / min between 800-1010 DEG C, and 1010 DEG C is kept for 5 min to obtain the foamed ceramic.

[0082] Test example

[0083] The foamed ceramic materials prepared in examples 1-4 are tested for performance, and the specific method is as follows:

[0084] The volume density of the sample is measured by using Archimedes method;

[0085] The true density of the sample is measured after being finely ground, and the porosity is obtained by calculation;

[0086] The internal cross-sectional morphology of the sample is photographed by using a digital camera, and the average pore size of the sample is counted by using image analysis software Image-Pro plus;

[0087] The compressive strength of the sample is measured by using a compression and bending resistance measuring all-in-one machine (YAW-3000);

[0088] The phase analysis of the sample powder is carried out by using an X-ray diffractometer.

[0089] The performance of the foamed ceramic materials prepared in examples 1-4 is shown in the following table:

[0090] Average pore size / mm Porosity / % Bulk density / kg / m 3 ]] Compressive strength / MPa Example 1 0.37 83.50 380 3.00 Example 2 1.99 76.77 590 2.73 Example 3 0.68 73.41 710 4.80 Example 4 0.29 77.36 420 3.50

[0091] The XRD patterns of the sample powders of the foamed ceramic materials prepared in examples 1 and 3 are shown in Figure 3 It can be seen that it is mainly composed of silicates such as quartz, iron oxide, anorthite and amorphous phase materials.

[0092] The foamed ceramic materials prepared in examples 1 and 4 have uniform pore distribution, high porosity, small pore size, light weight, and the compressive strength is greater than the specified 0.3 MPa standard.

[0093] The present application uses low-silicon high-calcium type iron tailings as flux material, which can completely replace feldspar, waste glass and other fluxing materials to reduce production cost, reduce the amount of foaming agent, and greatly reduce the sintering temperature, and cooperate with other solid waste materials, so as to solve the problems of resource utilization and high value of bulk mining waste.

[0094] The above only describes the preferred embodiments of the present application, and is not used to limit the present application, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A foamed ceramic material based on low-silica high-calcium type iron tailings, characterized by, The raw materials include, in percentage by weight, 20-60 wt% of low-silicon high-calcium type iron tailings, 24-60 wt% of barren material, 15-35 wt% of plastic material, and 0.1-0.5 wt% of foaming agent, wherein the foaming agent is in percentage by weight of the total weight of the iron tailings, the barren material and the plastic material; the foaming agent is silicon carbide, and the firing temperature is 990-1050℃; the low-silicon high-calcium type iron tailings include, in parts by weight, 8-20 wt% of SiO2, 2-8 wt% of Al2O3, 20-35 wt% of CaO, 1-3 wt% of MgO, 17-30 wt% of Fe2O3, and 15-30 wt% of loss on ignition; the barren material is high-silica material including quartz powder and fly ash; and the plastic material is clay mineral including kaolin and bentonite.

2. The foamed ceramic material based on low-silica high-calcium type iron tailings according to claim 1, characterized by: The plastic material includes, in percentage by weight, 30-55 wt% of SiO2, 40-70 wt% of Al2O3, and the balance of calcium, magnesium and iron oxides.

3. The foamed ceramic material based on low-silica high-calcium type iron tailings according to claim 1, characterized by: The barren material includes, in percentage by weight, 65-99 wt% of SiO2, 0-40 wt% of Al2O3, and the balance of calcium, magnesium and iron oxides.

4. A method for the production of a foamed ceramic material based on low-silica high- calcium type iron tailings according to any one of claims 1 to 3, characterized in that, The method includes the following steps: S1, mechanically dry-mixing the raw materials after fine grinding; S2, adding water to disperse and mix to obtain a slurry, and drying and forming the slurry to obtain a green body; S3, sintering the green body, and cutting the sintered green body after cooling to obtain a foamed ceramic material; In step S3, the firing temperature is 990-1050℃, the heating rate is 10℃ / min between 0-400℃, 5-7℃ / min between 400-800℃, 3-4℃ / min between 800-1000℃, 3℃ / min from 1000℃ to the firing temperature, the holding time is 5-10 min, and the sintered product is naturally cooled; Air is circulated throughout the heating process.

5. The method for preparing a foamed ceramic material based on low-silica high- calcium type iron tailings according to claim 4, characterized in that: In step S1, the fineness of the barren material, the plastic material and the low-silicon high-calcium type iron tailings is below 200 mesh, and the foaming agent is silicon carbide with a fineness of 325-1000 mesh.

6. The method for preparing a foamed ceramic material based on low-silica high- calcium type iron tailings according to claim 4, characterized in that: In step S1, the raw materials are fully mixed after being stirred at a speed of 5-20 r / s for 30-60 s in the mechanical dry-mixing process.

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