Modification preparation method based on coal series kaolin

Abstract

The invention discloses a modification preparation method based on coal series kaolinite, which is characterized in that coal gangue is taken as a raw material, performance modification is carried out, local characteristics of Da Guangdong kiln porcelain are combined, accurate formula development is carried out, requirements of Da Guangdong kiln porcelain products are met, and the Da Guangdong kiln porcelain products are enabled, so that technical innovation of the products is expected to be achieved; therefore, the purpose of serving local economy to realize research and application of the performance of the smoothing coal-series kaolins is achieved. The invention relates to the technical field of kaolin modification treatment. According to the modification preparation method based on coal series kaolinite, different reagents such as citric acid, urea, potassium acetate, triethanolamine and ammonium fluoride are used for modifying kaolinite, the modified kaolinite is applied to a ceramic blank, the performance of a ceramic sample is greatly improved, the breaking strength of ceramic can be improved, and the firing temperature of the ceramic can be reduced; and the energy consumption required by ceramic production can be reduced.

Description

Technical Field

[0001] The invention relates to the technical field of kaolin modification and treatment, in particular to a modification and preparation method based on coal-based kaolin. Background Art

[0002] Kaolin is one of the most widely distributed and commonly used clay minerals on earth. Its main mineral component is kaolinite, which is formed by the long-term weathering process of aluminum silicate minerals such as feldspar and common pyroxene in nature. Kaolin is mostly dense or loose blocks, the aggregate is dull or waxy, generally white, and if it contains impurities, it will be another color. It is a typical layered clay mineral. Due to its abundant reserves, low price and environmental friendliness, kaolin minerals have become a raw material widely used in hundreds of industries such as ceramic industry, papermaking industry, refractory materials and cement industry, petrochemical industry, medicine and textiles, and have become one of the most important industrial minerals at present. Naturally produced kaolin ores can generally be divided into three types: hard (coal-based) kaolin, soft kaolin and sandy kaolin according to their quality (physical and chemical properties), plasticity and sand content.

[0003] Coal-bearing kaolin, also known as coal gangue, is a solid waste discharged during the coal mining and coal washing process. It is a black-gray rock with a low carbon content and harder than coal that is associated with coal seams during the coal formation process. Its main components are Al 2 O 3 、SiO 2 , and also contains varying amounts of Fe 2 O 3 , CaO, MgO, Na 2 O.K 2 O.P 2 O 5 、SO 3 and trace rare elements (gallium, vanadium, titanium, cobalt). Gangue is a mixture of carbonaceous, muddy and sandy shales with low calorific value. It contains 20% to 30% carbon, and some contain humic acid. Gangue is abandoned and occupies large tracts of land. The escape or leaching of sulfides in gangue will pollute the atmosphere, farmland and water bodies. Gangue can also spontaneously combust and cause fires, or collapse in the rainy season, silting up rivers and causing disasters.

[0004] In the papermaking industry, kaolin is often used as a filler for paper because it is not easy to react with other ingredients. Kaolin particles are fine and have strong fluidity, which can ensure the uniform thickness of paper coating. Kaolin can fill the gaps between paper fibers, reduce the transparency of paper, improve flatness, and enhance the ink absorption capacity of paper. Therefore, it can partially replace other expensive fillers without affecting product quality.

[0005] Kaolin has high refractoriness and is often used in the processing of refractory products. Some low-quality kaolin has various defects, such as low whiteness and large particle size, and is usually not used in the ceramic and paper industries, but can be used as an excellent raw material for refractory materials.

[0006] In the rubber industry, kaolin is often mixed into colloid mixtures to improve the wear resistance, mechanical properties and chemical stability of rubber. As a filler, kaolin also reduces the use of other raw materials in rubber production, significantly reducing rubber production costs without affecting rubber performance.

[0007] In the building materials industry, kaolin becomes metakaolin after the moisture is removed, which can be prepared into geopolymer or added to concrete to improve the compressive strength and durability of the concrete, and to a certain extent can resist the shrinkage phenomenon caused by the solidification of concrete.

[0008] Kaolin can also be used in the field of FCC catalysts, mainly as a catalyst carrier to improve the anti-wear performance of the catalyst carrier. It is also possible to grow Y-type molecular sieve catalysts directly on kaolin microspheres by hydrothermal crystallization, a FCC catalyst carrier with great development potential. The application of kaolin in the ceramic field is much earlier than in other fields, and the amount used in traditional ceramic blanks can account for 20% to 30% of the composition. In ceramic blanks, kaolin can increase the Al2O 3 content, promotes the formation of mullite, improves the stability of ceramics and the strength of products. At the same time, kaolin can also increase the firing temperature range of ceramics, the ceramic body is not easy to change shape, and to a certain extent can improve the whiteness of the product. However, in the ceramic process, there are high requirements for the fineness and crystallinity of kaolin. Therefore, kaolin needs to be modified to improve the quality of kaolin and increase the utilization rate of kaolin.

[0009] Hu Xueting and others successfully prepared aluminum sulfate and polyaluminum sulfate by reacting sulfuric acid with kaolin without calcination. The flocculation effect of polyaluminum sulfate was much better than that of ordinary polyaluminum sulfate.

[0010] Kaolinite will form metakaolin when calcined at 600℃-900℃. The treatment of kaolinite with inorganic acid can change the Al content in the phase transition process. 3+ The chemical environment makes Al 3+ With acid reaction activity, kaolin will more easily react with acidic substances to leach out Al 2 O 3 and Fe 2 O 3 Impurities, thereby changing the pore size, surface area, etc. of kaolin.

[0011] Kaolin reacts with hydrochloric acid, the reaction formula is as follows:

[0012] Al 2 O 3 ·2SiO 2 ·2H 2 O→Al 2 O 3 ·2SiO 2 +2H 2 O

[0013] Al 2 O 3 ·2SiO 2 +6HCl→2AlCl 3 6H 2 O+2SiO 2

[0014] 2AlCl 3 6H 2 O→Al 2 (OH) n Cl 6-n +nHCl+(12-n)H 2 O

[0015] React with sulfuric acid, the reaction formula is as follows:

[0016] Al 2 O 3 ·2SiO 2 ·2H 2 O+3H 2 SO 4 →Al 2 (SO 4 ) 3 18H 2 O+2SiO2

[0017] Ou Yan et al. used Longyan kaolin as raw material, treated kaolin with hydrochloric acid after calcination, and prepared acid-activated clay. Their research showed that acid treatment can increase the number of pores in kaolin and the average pore size of kaolin, while increasing the specific surface area and improving the reaction activity of catalytic cracking.

[0018] Liu Lina and her colleagues modified kaolin with hydrochloric acid of different concentrations. After analyzing the modified kaolin using infrared spectroscopy and scanning electron microscopy, they found that hydrochloric acid modification did not change the structure of kaolin. However, as the concentration of hydrochloric acid increased, the modified kaolin would gradually condense into flakes, stack tightly, and the pores would become smaller.

[0019] Liu Yajing et al. modified kaolin with hydrochloric acid and analyzed the adsorption of zinc ions in wastewater by hydrochloric acid-modified kaolin, and found that the modified kaolin had a significantly improved ability to remove zinc ions. EI Unuabonah et al. modified kaolin with NTB (sodium tetraborate), and the modified kaolin had an improved adsorption capacity for lead ions and other ions in wastewater.

[0020] Zhuo Yanyu et al. mixed kaolin with sulfuric acid solution evenly and reacted it in a water bath at 90°C for a period of time to prepare sulfuric acid-modified kaolin. The modified kaolin was characterized by programmed temperature desorption technology. The study showed that the specific surface area and the number of acid sites of kaolin could be increased by treating kaolin with sulfuric acid after calcination. Summary of the invention

[0021] 1. Technical issues to be resolved

[0022] In view of the shortcomings of the prior art, the present invention provides a modification and preparation method based on coal-based kaolin. Coal gangue has the advantages of strong refractoriness, high temperature resistance, high titanium and selenium content, etc., but poor viscosity is its main disadvantage. Combined with the requirements of Daguan kiln porcelain for kaolin, enhancing its viscosity and producing high-performance Daguan kiln porcelain is a key problem to be solved urgently.

[0023] (II) Technical solution

[0024] To achieve the above objectives, the present invention is implemented by the following technical scheme: a modification preparation method based on coal-based kaolin, specifically comprising the following steps:

[0025] S1. Modifying kaolin with a modifier;

[0026] S2. Analyze the modification effect of kaolin using Fourier infrared spectroscopy, calcine the modified kaolin, analyze the phase composition changes of the modified kaolin and the unmodified kaolin using XRD, and comprehensively evaluate the modification effect of the modifier on kaolin;

[0027] S3. Then, the modified kaolin is applied to different ceramic blanks. Kaolin modified with different modifiers is added to two ceramic blanks in different proportions. After preparing the samples, the flexural strength and water absorption of the samples are tested. The influence of the modified kaolin on the ceramic properties is analyzed. The samples are subjected to scanning electron microscopy analysis to study the influence of the modified kaolin on the microscopic morphology of the ceramics.

[0028] Preferably, the method for modifying kaolin in step S1 is as follows:

[0029] T1. The coal-based kaolin to be processed is first crushed and screened by a crushing and screening processing equipment, and passed through a 100-200 mesh sieve;

[0030] T2, placing the kaolin sieved in step T1 in a mixing device, adding a modifier, sodium tripolyphosphate and water, and mixing and stirring at a speed of 400-500 r / min and a temperature of 35-45° C. for 20-30 minutes to obtain a primary mixture;

[0031] T3, ball-milling the primary mixture of step T2, and then standing and dehydrating for 20-24 hours to obtain a secondary mixture;

[0032] T4. The secondary mixture obtained in step T3 is heated in a aging device at a temperature of 70-90° C. for 30-40 minutes, and then taken out to complete the modification treatment of the coal-based kaolin.

[0033] Preferably, during the aging process in step T4, the material is turned over once every 5-10 minutes by a turning device.

[0034] Preferably, the different ceramic blanks in step S3 are high-temperature ceramic blanks fired at 1300° C. and low-temperature ceramic blanks fired at 1200° C.

[0035] Preferably, the modifier is one of citric acid, urea, potassium acetate, triethanolamine or ammonium fluoride.

[0036] Preferably, the Fourier transform infrared spectroscopy analysis in step S2 is infrared spectroscopy, which is an effective method for identifying materials and analyzing the chemical structure of substances. It is widely used in qualitative, quantitative and phase analysis of substances, and studies the interactions between molecules. The most common use of infrared spectroscopy is to judge unknown substances by the position and shape of the absorption frequency of the spectrum, and can quantitatively analyze substances according to the intensity of the absorption peak.

[0037] Preferably, the XRD analysis in step S2 is an X-ray diffraction analysis, which is used to determine the atomic and molecular structure of the crystal. Due to the crystal structure inside the material, the incident X-ray beam can be diffracted to many specified directions, and the angles and intensities of these diffraction beams are measured to obtain a lot of information such as the chemical bonds of the particles.

[0038] Preferably, the scanning electron microscopy analysis in step S3 is performed using a scanning electron microscope, which utilizes secondary electron signal imaging to explore the surface morphology of the sample, observe the shape of the sample, and the crystal size structure. The resolution of the secondary electron image is high, and there is no obvious shadow effect, which is very conducive to the morphology observation of the rough surface and the fracture surface. A field emission electron microscope is used, and the sample is corroded with hydrofluoric acid for 2-3 minutes and ultrasonically cleaned before testing. The crystal phase distribution, morphology, quantity, size and microstructure of the fractured sample are observed using a scanning electron microscope.

[0039] (III) Beneficial effects

[0040] The present invention provides a modified preparation method based on coal-based kaolin. Compared with the prior art, the modified preparation method based on coal-based kaolin has the following beneficial effects: the modified preparation method based on coal-based kaolin uses coal gangue as raw material, and through performance modification, combines the local characteristics of Daguan kiln porcelain, and conducts precise formula development to meet the needs of Daguan kiln porcelain products, and empowers it, in order to achieve product technology innovation, thereby achieving the purpose of serving the local economy and realizing the performance research and application of Fushun coal-based kaolin, and uses different reagents such as citric acid, urea, potassium acetate, triethanolamine, ammonium fluoride and other reagents to modify kaolin, and the modified kaolin is applied to ceramic blanks, which greatly improves the performance of ceramic samples, can improve the flexural strength of ceramics and reduce the firing temperature of ceramics, and can reduce the energy consumption required for ceramic production. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 This is a flow chart of kaolin modification of the present invention;

[0042] Figure 2 This is an application diagram of the modified kaolin of the present invention. DETAILED DESCRIPTION

[0043] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0044] See also Figure 1-2 The embodiment of the present invention provides two technical solutions: a modification preparation method based on coal-based kaolin, specifically including the following embodiments:

[0045] Example 1: A modified preparation method based on coal-based kaolin, specifically comprising the following steps:

[0046] S1. Modifying kaolin with a modifier;

[0047] S2. Analyze the modification effect of kaolin using Fourier infrared spectroscopy, calcine the modified kaolin, analyze the phase composition changes of the modified kaolin and the unmodified kaolin using XRD, and comprehensively evaluate the modification effect of the modifier on kaolin;

[0048] S3. Then, the modified kaolin is applied to different ceramic blanks. Kaolin modified with different modifiers is added to two ceramic blanks in different proportions. After preparing the samples, the flexural strength and water absorption of the samples are tested. The influence of the modified kaolin on the ceramic properties is analyzed. The samples are subjected to scanning electron microscopy analysis to study the influence of the modified kaolin on the microscopic morphology of the ceramics.

[0049] In the embodiment of the present invention, the method for modifying kaolin in step S1 is specifically as follows:

[0050] T1. The coal-based kaolin to be processed is first crushed and screened by a crushing and screening processing equipment, and passed through a 100-200 mesh sieve;

[0051] T2, placing the kaolin sieved in step T1 in a mixing device, adding a modifier, sodium tripolyphosphate and water, and mixing and stirring at a speed of 400-500 r / min and a temperature of 35-45° C. for 20-30 minutes to obtain a primary mixture;

[0052] T3, ball-milling the primary mixture of step T2, and then standing and dehydrating for 20-24 hours to obtain a secondary mixture;

[0053] T4. The secondary mixture obtained in step T3 is heated at 70-90° C. for 30-40 minutes in a aging device, and then taken out to complete the modification of the coal-based kaolin. During the aging process in step T4, the material is turned over once every 5-10 minutes by a turning device.

[0054] In the embodiment of the present invention, the different ceramic blanks in step S3 are high-temperature ceramic blanks fired at 1300° C. and low-temperature ceramic blanks fired at 1200° C.

[0055] In the embodiment of the present invention, the modifier is one of citric acid, urea, potassium acetate, triethanolamine or ammonium fluoride.

[0056] In the embodiment of the present invention, the Fourier transform infrared spectroscopy analysis in step S2 is an effective method for identifying materials and analyzing the chemical structure of substances. It is widely used in qualitative, quantitative and phase analysis of substances and studies the interactions between molecules. The most common use of infrared spectroscopy is to judge unknown substances by the position and shape of the absorption frequency of the spectrum, and to quantitatively analyze substances according to the intensity of the absorption peak.

[0057] Example 2: The technical solution of the embodiment of the present invention compared to Example 1 is that the XRD analysis in step S2 is X-ray diffraction analysis, which is used to determine the atomic and molecular structure of the crystal. Due to the crystal structure inside the material, the incident X-ray beam can be diffracted to many specified directions, and the angles and intensities of these diffraction beams are measured to obtain a lot of information such as the chemical bonds of the particles.

[0058] In the embodiment of the present invention, the scanning electron microscopy analysis in step S3 adopts a scanning electron microscope, and utilizes secondary electron signal imaging to explore the surface morphology of the sample, and observe the shape, crystal size structure of the sample. The resolution of the secondary electron image is high, and there is no obvious shadow effect, which is very conducive to the morphology observation of the rough surface and the fracture surface. A field emission electron microscope is used, and the sample is corroded with hydrofluoric acid for 2-3 minutes and ultrasonically cleaned before testing. The crystal phase distribution, morphology, quantity, size and microstructure of the fracture sample are observed using a scanning electron microscope.

[0059] The modified kaolin is added to different ceramic blanks in different proportions to prepare test bars, which are fired at different temperatures and tested and characterized. The application process is as follows: Figure 2 shown.

[0060] Flexural strength: Although the design of many materials is generally based on the tensile strength of the material, inorganic materials are usually very brittle. During tensile tests, the specimens are prone to break at the clamped position and will be affected by the additional bending moment caused by the inconsistency between the fixture and the axis of the specimen. Therefore, in practical applications, only the bending method can be used to determine the material's fracture strength, that is, the sample's flexural strength.

[0061] The "Test Method for Flexural Strength of Engineering Ceramics" formulated by my country stipulates that the flexural strength of ceramic materials can be determined by three-point bending or four-point bending tests.

[0062] Water absorption rate: Among the many performance indicators of ceramics, water absorption rate is one of the important indicators of ceramic performance. For most inorganic materials, the elastic modulus decreases with the increase of the porosity of the material. Since the fracture surface energy refers to the energy consumed by the newly formed fracture surface per unit area of ​​the material, it is obvious that with the increase of porosity, the fracture surface energy of the material also tends to decrease; in addition, the pores themselves as a defect may also become the most dangerous cracks inside the material. Therefore, under normal circumstances, the increase of porosity, especially the increase of apparent porosity, will also reduce the fracture strength of the material, and the increase of apparent porosity will increase the water absorption rate of the material. In addition, the magnitude of water absorption rate is also related to the sintering degree and sintering density of the ceramic, so water absorption rate becomes one of the indicators to characterize the degree of vitrification of the sample after firing. Generally speaking, the water absorption rate below 0.5% is fine porcelain, the water absorption rate less than 1% is ordinary porcelain, the water absorption rate less than 5% is stoneware, and the water absorption rate of pottery is generally greater than 10%.

[0063] Meanwhile, the contents not described in detail in this specification belong to the prior art known to those skilled in the art.

[0064] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0065] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A modified preparation method based on coal-based kaolin, characterized in that: The specific steps include: S1. Modifying kaolin with a modifier; S2. Analyze the modification effect of kaolin using Fourier infrared spectroscopy, calcine the modified kaolin, analyze the phase composition changes of the modified kaolin and the unmodified kaolin using XRD, and comprehensively evaluate the modification effect of the modifier on kaolin; S3. Then, the modified kaolin is applied to different ceramic blanks. Kaolin modified with different modifiers is added to two ceramic blanks in different proportions. After preparing the samples, the flexural strength and water absorption of the samples are tested. The influence of the modified kaolin on the ceramic properties is analyzed. The samples are subjected to scanning electron microscopy analysis to study the influence of the modified kaolin on the microscopic morphology of the ceramics.

2. The modified preparation method based on coal-based kaolin according to claim 1, characterized in that: The method for modifying kaolin in step S1 is specifically as follows: T1. The coal-based kaolin to be processed is first crushed and screened by a crushing and screening processing equipment, and passed through a 100-200 mesh sieve; T2, placing the kaolin sieved in step T1 in a mixing device, adding a modifier, sodium tripolyphosphate and water, and mixing and stirring at a speed of 400-500 r / min and a temperature of 35-45° C. for 20-30 minutes to obtain a primary mixture; T3, ball-milling the primary mixture of step T2, and then standing and dehydrating for 20-24 hours to obtain a secondary mixture; T4. The secondary mixture obtained in step T3 is heated in a aging device at a temperature of 70-90° C. for 30-40 minutes, and then taken out to complete the modification treatment of the coal-based kaolin.

3. A modified preparation method based on coal-based kaolin according to claim 2, characterized in that: In the step T4, during the aging process, the material is turned over once every 5-10 minutes by a turning device.

4. The modified preparation method based on coal-based kaolin according to claim 1, characterized in that: The different ceramic blanks in step S3 are high-temperature ceramic blanks fired at 1300° C. and low-temperature ceramic blanks fired at 1200° C.

5. A modified preparation method based on coal-based kaolin according to any one of claims 1 to 4, characterized in that: The modifier is one of citric acid, urea, potassium acetate, triethanolamine or ammonium fluoride.

6. The modified preparation method based on coal-based kaolin according to claim 1, characterized in that: The Fourier transform infrared spectroscopy analysis in step S2 determines unknown substances by the position and shape of the absorption frequency of the spectrum, and can quantitatively analyze substances according to the intensity of the absorption peak.

7. The modified preparation method based on coal-based kaolin according to claim 1, characterized in that: The XRD analysis in step S2 is an X-ray diffraction analysis, which is used to determine the atomic and molecular structure of the crystal. Due to the crystal structure inside the material, the incident X-ray beam can be diffracted to many specified directions, and the angle and intensity of these diffraction beams are measured to obtain a lot of information such as the chemical bonds of the particles.

8. The modified preparation method based on coal-based kaolin according to claim 1, characterized in that: The scanning electron microscope analysis in step S3 adopts a scanning electron microscope, and utilizes secondary electron signal imaging to explore the surface morphology of the sample, observe the shape of the sample, and the crystal size structure. The resolution of the secondary electron image is high, and there is no obvious shadow effect, which is very conducive to the morphology observation of the rough surface and the fracture surface. A field emission electron microscope is used. The sample is corroded with hydrofluoric acid for 2-3 minutes and ultrasonically cleaned before testing. The crystal phase distribution, morphology, quantity, size and microstructure of the fracture sample are observed using a scanning electron microscope.

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