A method for preparing ceramic blank materials using kaolin as raw material

Abstract

This application relates to the technical field of ceramic raw materials, and particularly to a method for preparing ceramic blank materials using kaolin as a raw material. A method for preparing ceramic blank materials using kaolin as a raw material, through process steps such as classification, delamination, low-temperature superconducting magnetic separation, beneficiation, pickling for whitening, pressure filtration and dehydration, especially through the synergistic effect of permanent magnet, electromagnetic, and superconducting high-gradient magnetic separators for efficient purification, pickling for whitening and other processes, greatly improves the grade of kaolin and obtains high-grade kaolin with a whiteness value not lower than 93%. The obtained high-grade kaolin is applied to the ceramic field.

Description

Technical Field

[0001] This application relates to the technical field of ceramic raw materials, and particularly to a method for preparing ceramic blank materials using kaolin as a raw material. Background Art

[0002] Currently, ceramic raw materials mainly come from various natural minerals such as clay and feldspar, and these raw materials are all non-renewable resources. The production of ceramics will inevitably lead to the consumption of natural resources. With the continuous innovation of technology, the performance of products has been continuously developed in depth, and the application scope of products has also been continuously broadened. Preparing standard general raw materials for ceramics is conducive to optimizing the rational utilization of natural resources. Construction waste soil contains a large amount of kaolin. If the construction waste soil can be utilized to prepare general ceramic raw materials, waste utilization can be achieved and energy can be saved. The preparation of general ceramic raw materials necessarily requires a more refined raw material classification system to clarify the applicable scope of raw materials, standardize and systematize the specifications of raw materials, so as to replace some natural resources of porcelain clay and reduce the consumption of natural energy. At present, there are many impurities in the kaolin contained in construction waste soil, so it is necessary to select useful kaolin through physical and chemical treatment means, remove impurity components, and reduce the content of harmful elements to meet the technical indicators of ceramic blank materials. Summary of the Invention

[0003] In order to solve the problems of removing impurity components from kaolin and reducing the content of harmful elements to meet the requirements of ceramic blank materials, this application provides a method for preparing ceramic blank materials using kaolin as a raw material.

[0004] The following technical scheme is adopted:

[0005] A method for preparing ceramic blank materials using kaolin as a raw material, comprising the following steps:

[0006] S1. Classification: Put the kaolin raw material into a pulp tank, beat the pulp and add a dispersant, then stir to obtain a slurry with a mass concentration of 16 - 20%, and pass the slurry through a small-diameter hydrocyclone for precise classification, and take the underflow for standby;

[0007] S2. Flaking: Subject the classified kaolin underflow to high-speed shear flaking through a flaker.

[0008] S3. Low-temperature superconducting magnetic separation: Remove weakly magnetic minerals from the flaked slurry through the collaborative operation of a permanent magnet, electromagnetic, and superconducting magnetic separator. The magnetic field strength of the superconducting magnetic separator is 5 - 5.5T to obtain coarse-grained kaolin.

[0009] S4. Screening: Screen the slurry with a mass concentration of 50 - 65% of coarse - grained kaolin. The screening is carried out in two steps, the first screening and the second screening. In the first screening, the coarse - grained kaolin is added to the screening tank, water is added for mixing and pulping, and stirring is started to control the mass concentration of the slurry at 50 - 65% and the slurry temperature at 40 - 50°C. During the stirring process, a dispersant, a first - screening collector, and a foaming agent are added in sequence for the first screening. After the first screening is completed, the kaolin obtained after the first screening is then subjected to the second screening. During the stirring process, a second - screening collector is added again. After the second screening, high - grade kaolin A is obtained;

[0010] S5. Acid pickling and whitening: For the high - grade kaolin A with a mass concentration of 25% after screening, the pH is adjusted to 1.8 - 2.5 with sulfuric acid. While stirring, a reducing agent is slowly added. After the addition of the medicine, stirring continues for 30 min to allow sufficient reaction. After that, iron ions are removed by filling and pressure filtration, and kaolin B after iron removal by acid pickling is obtained;

[0011] S6. Pressure filtration: The kaolin B after iron removal treatment is pressure - filtered with a filter press to obtain a filter cake. The filter cake is rinsed 3 - 4 times with circulating water, and the rinsing liquid after rinsing the filter cake is collected and recycled;

[0012] S7. Drying: The filter cake treated in step S6 is dried to obtain kaolin for ceramic billets.

[0013] By adopting the above technical solutions, each step plays a specific role and cooperates with each other to obtain high-quality kaolin for ceramic billet. In step S1, the purpose of classification is to remove impurities and coarse particles from the kaolin raw material to obtain relatively pure kaolin slurry. The use of a hydrocyclone can achieve particle size classification and separation. In step S2, the high-speed shearing and peeling of the peeler can further refine the kaolin underflow, increasing its surface area and dispersibility. In step S3, the purpose of low-temperature superconducting magnetic separation is to remove magnetite and other weakly magnetic minerals from the kaolin slurry, which can efficiently separate the weakly magnetic impurities in construction waste (kaolin), thereby significantly reducing the iron and titanium content in construction waste (kaolin), while improving the whiteness of the sample. The superconducting magnetic separation process has advantages such as environmental friendliness, low processing cost, and high automation. In step S4, by adjusting the slurry concentration, temperature, and added agents, the first and second selections of kaolin can be achieved to obtain high-grade kaolin. In step S5, the purpose of acid washing and whitening is to remove iron elements from kaolin. First, the oxides of trivalent iron in kaolin are converted into solution with acid, and then the trivalent iron ions are reduced to divalent iron ions soluble in water by the hydrogen generated by the reaction of acid with active metal zinc powder or aluminum powder, further improving the whiteness value of high-grade kaolin A. In step S6, the iron-removed kaolin is filtered and washed by a filter press to remove excess water and obtain a relatively dry kaolin filter cake. In step S7, drying the filter cake can make the kaolin reach the moisture content suitable for preparing ceramic billet materials. Through the synergistic effect of each of the above steps, high-quality kaolin for ceramic billet with a whiteness value not lower than 93% can be obtained. Each step plays a key role in removing impurities, improving purity, and improving particle state and dispersibility, thus ultimately improving the quality of kaolin for ceramic billet.

[0014] Preferably, in step S1 and step S4, the dispersant is a composition of sodium silicate, carboxymethyl cellulose, and polyvinylpyrrolidone k30 in a mass ratio of 6:1 - 3:1 - 2, and the addition amount is 0.6 - 2.0 g / L.

[0015] By adopting the above technical solution, in the present application, the role of the dispersant is to disperse the kaolin raw material evenly and prevent its agglomeration, so as to obtain a slurry with stable performance. The composition of sodium silicate, carboxymethyl cellulose, and polyvinylpyrrolidone k30 as a dispersant can effectively reduce the adsorption force and electrostatic interaction between kaolin particles, making it easier to disperse. In step S4, the role of the dispersant is to further disperse kaolin during the beneficiation process. At the same time, the dispersant can also reduce the adsorption force between kaolin and the collector, increasing the beneficiation effect. The composition of sodium silicate, carboxymethyl cellulose, and polyvinylpyrrolidone k30 has a synergistic effect in the present application. Through complementary actions, the dispersion effect of the dispersant is enhanced. Sodium silicate can improve the adsorption ability of the dispersant to kaolin; carboxymethyl cellulose can improve the dispersion effect of the dispersant and has a gelling effect; polyvinylpyrrolidone k30 can increase the viscosity of the dispersant and increase the dispersion effect. Using these three dispersants in combination can better achieve the dispersion of kaolin and improve the quality of the ceramic blank material.

[0016] Preferably, in step S4, the first beneficiation collector is prepared from the following raw materials in parts by mass: 3 - 5 parts of sodium petroleum sulfonate, 2 - 4 parts of polyacrylamide, 1 - 2 parts of oleic acid, 1 - 2 parts of alkylphenol polyoxyethylene ether, 1 - 2 parts of cetyltrimethylammonium bromide, 1 - 2 parts of disodium oxalate, and 20 - 25 parts of water.

[0017] Preferably, the preparation method of the first beneficiation collector is: according to the parts by mass, mix sodium petroleum sulfonate, polyacrylamide, oleic acid, alkylphenol polyoxyethylene ether, cetyltrimethylammonium bromide, disodium oxalate, and water and stir evenly to obtain a mixture. Then add the mixture into a reaction kettle, heat it to boiling, and keep the solution boiling for 20 - 30 min. Then naturally cool the solution to room temperature to obtain the first beneficiation collector.

[0018] Preferably, the addition amount of the first beneficiation collector is 0.6 - 2.5 g / L.

[0019] By adopting the above technical solution, the first-stage beneficiation collector is an important formula raw material, which is composed of sodium petroleum sulfonate, polyacrylamide, oleic acid, alkylphenol polyoxyethylene ether, cetyltrimethylammonium bromide, disodium oxalate and water. The first-stage beneficiation collector plays an important role and synergistic effect during the beneficiation process. Specifically: Sodium petroleum sulfonate: Changes the surface properties of mineral particles and improves the beneficiation effect. Polyacrylamide: Has strong adsorption ability, can adsorb on the surface of mineral particles to form a protective film, and improves the beneficiation effect. Oleic acid: Can form chelates with cations on the surface of mineral particles, increases the hydrophobicity of particles, and improves the beneficiation effect. Alkylphenol polyoxyethylene ether: Has good dispersion performance, can disperse mineral particles, avoid particle aggregation, and improves the beneficiation effect. Cetyltrimethylammonium bromide: Is a cationic surfactant, can improve the hydrophilicity of mineral particles, and improves the beneficiation effect. Disodium oxalate: Can undergo a complexation reaction with calcium ions, reduce the adhesion substances on the surface of mineral particles, and improves the beneficiation effect. These raw materials interact synergistically during the preparation of the first-stage beneficiation collector to improve the effect of the kaolin beneficiation process and reduce the content of undesirable minerals.

[0020] Preferably, in step S4, the second-stage beneficiation collector is one or more of polyacrylamide, cetyltrimethylammonium bromide, and sodium polyphosphate, and the addition amount of the second-stage beneficiation collector is 0.3 - 1.5 g / L.

[0021] By adopting the above technical solution, the second-stage beneficiation collector can selectively adsorb impurities and minerals on the surface of kaolin B, thereby achieving a separation effect. By selecting a suitable second-stage beneficiation collector, the beneficiation rate of kaolin B during the beneficiation process can be increased, and the grade of kaolin can be improved. The second-stage beneficiation collector can also act as a dispersant and a foaming agent, helping kaolin B to better disperse in the slurry and form fine bubbles during the beneficiation process. This helps to improve the beneficiation effect and increase the recovery rate of kaolin B. The second-stage beneficiation collector plays a role in separating and purifying kaolin. By reasonably selecting the second-stage beneficiation collector and controlling its addition amount, the purpose of improving the grade and recovery rate of kaolin B can be achieved.

[0022] Preferably, in step S4, the foaming agent is No. 2 oil, and its addition amount is 0.2 - 0.5 g / L.

[0023] By adopting the above technical solution, the function of the No. 2 oil foaming agent is to introduce air foam. Through the adhesion and separation with impurities, the impurities float on the surface of the slurry, so as to achieve the purpose of reducing the impurity content and improving the quality of kaolin. The foaming agent can enhance the dispersibility and foamability of the slurry, and promote the separation of kaolin from the impurities in the slurry. The No. 2 oil foaming agent acts together with the dispersant, the first beneficiation collector and the second beneficiation collector, etc., and synergistically plays a better effect of removing impurities and improving the quality of kaolin.

[0024] Preferably, in step S5, the reducing agent is zinc powder or aluminum powder, and the addition amount is 0.1%-0.2% of the mass of high-grade kaolin A.

[0025] By adopting the above technical solution, first, the oxides of trivalent iron in kaolin are converted into the solution with acid, and then the hydrogen gas generated by the reaction of the acid with the active metal zinc powder or aluminum powder reduces the trivalent iron ions into divalent iron ions soluble in water, so as to further improve the whiteness value of high-grade kaolin A.

[0026] Preferably, in step S7, the filter cake is dried to form a block sample, and after calcination at 1280°C, the whiteness value of the sample is not less than 93%.

[0027] In summary, the beneficial technical effects of the present application: The method of the present application uses kaolin as the raw material to prepare ceramic blank materials. Through steps such as classification, delamination, low-temperature superconducting magnetic separation, beneficiation, reduction bleaching, pressure filtration and drying, through the synergistic effect of permanent magnet, electromagnetic and superconducting high-gradient magnetic separators for efficient purification, pickling and whitening and other processes, the grade of kaolin is greatly improved, and high-grade kaolin with a whiteness value not less than 93% is obtained. The obtained kaolin can be used to prepare high-quality ceramic blanks, has better physical properties and appearance effects, and the obtained high-grade kaolin is applied to the ceramic field. Specific Embodiments

[0028] The following will describe the implementation plan of the present application in detail in conjunction with the embodiments. However, those skilled in the art will understand that the following embodiments are only used to illustrate the present application and should not be regarded as limiting the scope of the present application. Those not specified in the embodiments are carried out according to the conventional conditions or the conditions recommended by the manufacturer. Those reagents or instruments not specified by the manufacturer can be obtained as conventional products through commercial purchase.

[0029] Example 1

[0030] A method for preparing ceramic blank materials with kaolin as the raw material, including the following steps:

[0031] S1. Classification: Put 1000 kg of kaolin raw materials into a pulp tank for pulping and add a dispersant. The dispersant is a composition of sodium silicate, carboxymethyl cellulose, and polyvinylpyrrolidone k30 in a mass ratio of 6:3:2, with an addition amount of 2.0 g / L. Stir to obtain a slurry with a mass concentration of 20%. Pass the slurry through a small-diameter hydrocyclone for precise classification, and take the underflow for standby;

[0032] S2. Flaking: Subject the classified kaolin underflow to high-speed shear flaking through a flaker.

[0033] S3. Low-temperature superconducting magnetic separation: Remove weakly magnetic minerals from the flaked slurry through the collaborative operation of a permanent magnet, electromagnetic, and superconducting magnetic separator. The magnetic field intensity of the superconducting magnetic separator is 5 T to obtain coarse-grained kaolin.

[0034] S4. Concentration: Concentrate the slurry of coarse-grained kaolin with a mass concentration of 65%. The concentration is carried out by the first concentration and the second concentration. In the first concentration, add the coarse-grained kaolin to a concentration tank, add water for mixing and adjusting the slurry, and start stirring to control the mass concentration of the slurry at 65% and the slurry temperature at 50 °C. During the stirring process, add a dispersant, a first-concentration collector, and a foaming agent in sequence. The foaming agent is No. 2 oil with an addition amount of 0.5 g / L for the first concentration. After the first concentration is completed, then subject the kaolin obtained after the first concentration to the second concentration. During the stirring process, add a second-concentration collector. The second-concentration collector is polyacrylamide with an addition amount of 1.5 g / L. After the second concentration, obtain high-grade kaolin A. The dispersant is a composition of sodium silicate, carboxymethyl cellulose, and polyvinylpyrrolidone k30 in a mass ratio of 6:3:2, with an addition amount of 2.0 g / L; The first-concentration collector is prepared from the following raw materials in parts by mass: 5 kg of sodium petroleum sulfonate, 4 kg of polyacrylamide, 2 kg of oleic acid, 2 kg of alkylphenol polyoxyethylene ether, 2 kg of cetyltrimethylammonium bromide, 2 kg of disodium oxalate, and 25 kg of water. The addition amount of the first-concentration collector is 2.5 g / L. The preparation method of the first-concentration collector is: Mix the above sodium petroleum sulfonate, polyacrylamide, oleic acid, alkylphenol polyoxyethylene ether, cetyltrimethylammonium bromide, disodium oxalate, and water evenly to obtain a mixture, then add the mixture into a reaction kettle, heat to boiling, keep the solution boiling for 30 min, and then naturally cool the solution to room temperature to obtain the first-concentration collector;

[0035] S5, pickling and whitening: 400 kg of high-grade kaolin A with a mass concentration of 25% after selection was adjusted to a pH of 1.8 with sulfuric acid, and 0.1 kg of zinc powder was slowly added while stirring. After the addition of the drug, stirring was continued for 30 minutes to allow it to react fully, and then the iron ions were removed by filling and pressing to obtain kaolin B after acid washing and iron removal;

[0036] S6, filter pressing: filter the kaolin B after iron removal treatment with a filter press to obtain a filter cake, rinse the filter cake with circulating water for 4 times, collect the rinse liquid after rinsing the filter cake and recycle it;

[0037] S7, drying: drying the filter cake after being processed in step S6 to obtain kaolin for ceramic blank.

[0038] Example 2

[0039] A method for preparing ceramic blank material using kaolin as raw material comprises the following steps:

[0040] S1. Classification: 1000 kg of kaolin raw material was put into a slurry pool for slurrying and adding a dispersant, which was a composition of water glass, carboxymethyl cellulose and polyvinyl pyrrolidone k30 in a mass ratio of 6:1:1, with an addition amount of 0.6 g / L, and stirred to obtain a slurry with a mass concentration of 16%. The slurry was subjected to Small-caliber cyclones are used for accurate classification, and the bottom flow is taken for standby use;

[0041] S2, flaking: the classified kaolin bottom flow is passed through a flaking machine for high-speed shearing flaking;

[0042] S3, low-temperature superconducting magnetic separation: the flaked slurry is subjected to a three-way synergistic process of permanent magnet, electromagnetic and superconducting magnetic separators to remove weakly magnetic minerals. The magnetic field strength of the superconducting magnetic separator is 5.5T, and coarse-grained kaolin is obtained;

[0043] S4. Selection: The slurry with a mass concentration of 50% of coarse-grained kaolin is selected. The selection adopts the first selection and the second selection. In the first selection, the coarse-grained kaolin is added to the selection tank, water is added for mixing and pulping, and stirring is started to control the mass concentration of the slurry at 50%, the slurry temperature is 40 °C. During the stirring process, a dispersant, a collector for the first selection, and a foaming agent are added in sequence. The foaming agent is No. 2 oil, and its addition amount is 0.2 g / L for the first selection. After the first selection is completed, the kaolin obtained after the first selection is then subjected to the second selection. During the stirring process, a collector for the second selection is added again. The collector for the second selection is cetyltrimethylammonium bromide, and its addition amount is 0.3 g / L. After the second selection, high-quality kaolin A is obtained. The dispersant is a composition of sodium silicate, carboxymethyl cellulose, and polyvinylpyrrolidone k30 in a mass ratio of 6:1:1, and the addition amount is 0.6 g / L. The collector for the first selection is prepared from the following raw materials in parts by mass: 3 kg of petroleum sulfonate, 2 kg of polyacrylamide, 1 kg of oleic acid, 1 kg of alkylphenol polyoxyethylene ether, 1 kg of cetyltrimethylammonium bromide, 1 kg of disodium oxalate, and 20 kg of water. The addition amount of the collector for the first selection is 0.6 g / L. The preparation method of the collector for the first selection is: mix the above petroleum sulfonate, polyacrylamide, oleic acid, alkylphenol polyoxyethylene ether, cetyltrimethylammonium bromide, disodium oxalate, and water and stir evenly to obtain a mixture, then add the mixture into the reaction kettle, heat it to boiling, keep the solution boiling for 20 min, and then naturally cool the solution to room temperature to obtain the collector for the first selection;

[0044] S5. Acid pickling and whitening: 400 kg of high-quality kaolin A with a mass concentration of 25% after selection is adjusted to a pH of 2.5 with sulfuric acid. While stirring, 0.2 kg of zinc powder is slowly added. After the addition of the medicine, stirring continues for 30 min to fully react, and then iron ions are discharged through filling and pressure filtration and dehydration to obtain kaolin B after acid pickling and iron removal;

[0045] S6. Pressure filtration: The kaolin B after iron removal treatment is pressure-filtered with a filter press to obtain a filter cake, and the filter cake is rinsed 3 times with circulating water. The rinsing liquid after rinsing the filter cake is collected and recycled;

[0046] S7. Drying: The filter cake treated in step S6 is dried to obtain kaolin for ceramic blank materials.

[0047] Example 3

[0048] A method for preparing kaolin for ceramic blank materials using kaolin as a raw material, comprising the following steps:

[0049] S1. Classification: Put 1000 kg of kaolin raw materials into a pulp tank for pulping and add a dispersant. The dispersant is a composition of sodium silicate, carboxymethyl cellulose, and polyvinylpyrrolidone k30 in a mass ratio of 6:2:1.5, with an addition amount of 1.3 g / L. Stir to obtain a slurry with a mass concentration of 18%. Pass the slurry through a small-diameter hydrocyclone for precise classification, and take the underflow for standby;

[0050] S2. Flaking: Subject the classified kaolin underflow to high-speed shear flaking through a flaker;

[0051] S3. Low-temperature superconducting magnetic separation: Remove weakly magnetic minerals from the flaked slurry through the collaborative operation of a permanent magnet, electromagnetic, and superconducting magnetic separator. The magnetic field strength of the superconducting magnetic separator is 5.3 T to obtain coarse-grade kaolin;

[0052] S4. Concentration: Concentrate the slurry of coarse-grade kaolin with a mass concentration of 58%. The concentration is carried out by the first concentration and the second concentration. In the first concentration, add the coarse-grade kaolin to a concentration tank, add water for mixing and adjusting the slurry, and start stirring to control the mass concentration of the slurry at 58% and the slurry temperature at 45°C. During the stirring process, add a dispersant, a first-concentration collector, and a foaming agent in sequence. The foaming agent is No. 2 oil with an addition amount of 0.3 g / L for the first concentration; after the first concentration is completed, then subject the kaolin obtained after the first concentration to the second concentration. During the stirring process, add a second-concentration collector. The second-concentration collector is sodium polyphosphate with an addition amount of 0.9 g / L. After the second concentration, high-quality kaolin A is obtained. The dispersant is a composition of sodium silicate, carboxymethyl cellulose, and polyvinylpyrrolidone k30 in a mass ratio of 6:2:1.5, with an addition amount of 1.3 g / L; the first-concentration collector is prepared from the following raw materials in parts by mass: 4 kg of sodium petroleum sulfonate, 3 kg of polyacrylamide, 1.5 kg of oleic acid, 1.5 kg of alkylphenol polyoxyethylene ether, 1.5 kg of cetyltrimethylammonium bromide, 1.5 kg of disodium oxalate, and 22 kg of water. The addition amount of the first-concentration collector is 1.5 g / L. The preparation method of the first-concentration collector is: Mix the above sodium petroleum sulfonate, polyacrylamide, oleic acid, alkylphenol polyoxyethylene ether, cetyltrimethylammonium bromide, disodium oxalate, and water evenly to obtain a mixture, then add the mixture to a reaction kettle, heat to boiling, keep the solution boiling for 25 min, and then naturally cool the solution to room temperature to obtain the first-concentration collector;

[0053] S5. Pickling and Whitening: 400 kg of high-grade kaolin A with a mass concentration of 25% after screening is adjusted to a pH of 2.2 with sulfuric acid. While stirring slowly, 0.15 kg of zinc powder is added. After the addition of the medicine, stirring continues for 30 min. After sufficient reaction, iron ions are removed by filling and pressure filtration and dewatering to obtain kaolin B after iron removal by pickling.

[0054] S6. Pressure Filtration: The iron-removed kaolin B is pressure-filtered with a filter press to obtain a filter cake. The filter cake is rinsed 4 times with circulating water, and the rinsing liquid after rinsing the filter cake is collected and recycled.

[0055] S7. Drying: The filter cake treated in step S6 is dried to obtain kaolin for ceramic blank.

[0056] Comparative Example 1

[0057] Same as Example 3, except that: in the steps, it does not go through S4, screening treatment.

[0058] Comparative Example 2

[0059] Same as Example 3, except that: in the steps, it goes through the first screening in S4, screening treatment and does not adopt the second screening treatment.

[0060] Comparative Example 3

[0061] Same as Example 3, except that: in the steps, it goes through the second screening in S4, screening treatment and does not adopt the first screening treatment first.

[0062] Comparative Example 4

[0063] Same as Example 3, except that: in the steps, it does not go through S5, pickling and whitening process.

[0064] Comparative Example 5

[0065] Same as Example 3, except that: in the steps, it does not go through S3, low-temperature superconducting magnetic separation process.

[0066] Performance Test

[0067] Samples are taken from the kaolin for ceramic blank obtained in Examples 1 - 3 and Comparative Examples 1 - 5 and calcined at 1280 °C. The whiteness and chemical composition of the samples are tested according to GB / T 14563 - 2020: Kaolin and Its Test Methods. The test results are shown in Table 1.

[0068] Table 1

[0069]

[0070] From the analysis of Examples 1-3 in Table 1, the kaolin used to prepare the ceramic blank has a whiteness value between 93.3% and 95.3% after calcination at 1280°C. The whiteness value is very high, and the obtained kaolin meets the requirements of the ceramic industry for raw materials.

[0071] From the comparative analysis of Example 3 and Comparative Examples 1-3 in Table 1, the whiteness value of the kaolin obtained by using the selected process of this application after calcination is higher than that of the kaolin obtained without the selected process or only with the first or second selection process in the selected process. This shows that the selected process of this application has a greater impact on the whiteness value of kaolin. By stirring and adding dispersants, the first collector, foaming agents, etc., the mass concentration and particle size of the slurry can be better controlled, the selection effect can be improved, the first and second selections of kaolin can be realized, and impurities can be better removed and high-grade kaolin can be obtained synergistically.

[0072] From the comparative analysis of Example 3 and Comparative Example 4 in Table 1, for the acid pickling and whitening of this application, first, the oxides of ferric iron in kaolin are converted into the solution with acid, and then the hydrogen generated by the reaction of the acid with active metal zinc powder or aluminum powder reduces the ferric iron ions into water-soluble ferrous iron ions, so as to further improve the whiteness value of high-grade kaolin A.

[0073] From the comparative analysis of Example 3 and Comparative Example 5 in Table 1, the purpose of using the low-temperature superconducting magnetic separation of this application is to remove magnetite and other weakly magnetic minerals from the kaolin slurry, and the weakly magnetic impurities in construction waste (kaolin) can be efficiently separated. Furthermore, the iron and titanium contents in construction waste (kaolin) can be significantly reduced, and at the same time, the whiteness of the sample can be improved. The superconducting magnetic separation process has the advantages of environmental friendliness, low treatment cost, high automation degree, etc.

[0074] The above embodiments are only used to explain and illustrate the technical solutions of the present invention rather than to limit it. Although the above embodiments have specifically described the present invention, those skilled in the art should understand that the specific implementation manners of the present invention can still be modified or equivalently replaced. Any modification and equivalent replacement without departing from the spirit and scope of the present invention shall be covered by the scope of the claims of the present invention.

Claims

1. A method for preparing ceramic blank materials using kaolin as a raw material, characterized in that, The following steps are involved: S1. Classification: Put the kaolin raw material into a pulp tank for pulping, add a dispersant, and stir to obtain a slurry with a mass concentration of 16 - 20%. Pass the slurry through a small-diameter hydrocyclone for precise classification, and take the underflow for standby; S2, flaking: the classified kaolin bottom flow is passed through a flaking machine for high-speed shearing flaking; S3, low-temperature superconducting magnetic separation: the flaked slurry is subjected to a three-way synergistic process of permanent magnet, electromagnetic and superconducting magnetic separators to remove weakly magnetic minerals. The magnetic field strength of the superconducting magnetic separator is 5-5.5T to obtain coarse-grained kaolin; S4, selection: the slurry with a mass concentration of 50-65% of coarse-grained kaolin is selected, and the selection adopts the first selection and the second selection. The first selection is to add the coarse-grained kaolin into the selection tank, add water to mix and slurry and start stirring, so that the mass concentration of the slurry is controlled at 50-65%, the slurry temperature is 40-50°C, and the dispersant, the first selection collector, and the foaming agent are added in sequence during the stirring process to perform the first selection; after the first selection is completed, the kaolin obtained after the first selection is then subjected to the second selection, and the second selection collector is added during the stirring process, and the high-grade kaolin A is obtained after the second selection; S5, pickling and whitening: adjust the pH of the selected 25% high-grade kaolin A to between 1.8 and 2.5 with sulfuric acid, slowly add the reducing agent while stirring, continue stirring for 30 minutes after the addition of the agent, allow it to react fully, and then dehydrate it through a filter press to remove iron ions, thereby obtaining the kaolin B after acid washing and iron removal; S6, filter pressing: filter the kaolin B with a filter press to obtain a filter cake, rinse the filter cake with circulating water for 3-4 times, collect the rinse liquid after rinsing the filter cake and recycle it; S7, drying: drying the filter cake after being processed in step S6 to obtain kaolin for ceramic blank; In step S4, the first cleaning collector is prepared from the following raw materials in parts by weight: 3-5 parts of sodium petroleum sulfonate, 2-4 parts of polyacrylamide, 1-2 parts of oleic acid, 1-2 parts of alkylphenol polyoxyethylene ether, 1-2 parts of hexadecyltrimethylammonium bromide, 1-2 parts of disodium oxalate, and 20-25 parts of water; The preparation method of the first selection collector is as follows: according to the mass fractions, sodium petroleum sulfonate, polyacrylamide, oleic acid, alkylphenol polyoxyethylene ether, hexadecyltrimethylammonium bromide, disodium oxalate and water are mixed and stirred uniformly to obtain a mixture, and then the mixture is added into a reaction kettle, heated to boiling, and the solution is kept in a boiling state for 20-30 minutes, and then the solution is naturally cooled to room temperature to obtain the first selection collector; The amount of the first cleaning collector added is 0.6-2.5 g / L; In step S4, the second selection collector is one or more of polyacrylamide, hexadecyltrimethylammonium bromide, and sodium polyphosphate, and the addition amount of the second selection collector is 0.3-1.5 g / L.

2. The method for preparing ceramic blank material using kaolin as raw material according to claim 1, characterized in that, In step S1, the dispersant is a composition of water glass, carboxymethyl cellulose and polyvinyl pyrrolidone k30 in a mass ratio of 6:1-3:1-2, and the added amount is 0.6-2.0 g / L.

3. The method for preparing ceramic blank materials using kaolin as raw material according to claim 1, characterized in that, In step S4, the dispersant is a composition of water glass, carboxymethyl cellulose and polyvinyl pyrrolidone k30 in a mass ratio of 6:1-3:1-2, and the added amount is 0.6-2.0 g / L.

4. The method for preparing ceramic blank material using kaolin as raw material according to claim 1, characterized in that, In step S4, the foaming agent is No. 2 oil, and its addition amount is 0.2 - 0.5 g / L.

5. The method for preparing ceramic blank material using kaolin as raw material according to claim 1, characterized in that, In step S5, the reducing agent is zinc powder or aluminum powder, and its addition amount is 0.1% - 0.2% of the mass of high-grade kaolin A.

6. The method for preparing ceramic blank material with kaolin as raw material according to claim 1, characterized in that, In step S7, the filter cake is dried to form a block sample. After calcination at 1280 °C, the whiteness value of the sample is not less than 93%.

Images