Impurity removal method of bone china raw material

Abstract

The invention relates to the technical field of ceramic production, in particular to a bone china raw material impurity removal method which comprises the following steps: step 1, primarily screening mixed slurry by using a 120-mesh grading mesh screen; step 2, carrying out primary fine screening on the mixed slurry subjected to primary screening by using a 180-mesh grading mesh screen; and 3, iron impurities are removed through a seven-step progressive electromagnetic iron removal method. According to the invention, a seven-filtering and five-screening process is applied, that is, slurry passes through a high-strength electromagnetic iron remover for seven times and passes through a high-mesh rotary vibration sieve for five times, iron impurities are removed by a progressive electromagnetic iron removal method, harmful impurities are completely removed, and the ceramic prepared from the raw materials is good in light transmittance, fine, smooth and transparent in texture, pure white and mild as jade in hue, and high in quality. And the product grade is obviously improved.

Description

Technical Field

[0001] The invention relates to the technical field of ceramic production, and in particular to a method for removing impurities from bone china raw materials. Background Art

[0002] In the production process of daily-use ceramics, the raw material preparation process is the basic process, the purpose of which is to add water to the multi-component formula raw materials and crush them into slurry to obtain fine raw material particles that are conducive to the sintering reaction. At the same time, the iron-containing color-developing impurities and trace amounts of coarse particles in the slurry are removed, which seriously affect the whiteness and light transmittance of the porcelain, affecting the appearance of the porcelain. Bone china belongs to the category of daily-use ceramics and is a world-recognized high-end porcelain. It uses exquisite materials, is finely made, and has strict standards. It is characterized by high porcelain whiteness, delicate and transparent, and a moist and bright glaze.

[0003] The most feared problem in bone china production is iron contamination, which may affect the whiteness of the porcelain body at the least and cause mud defects that may downgrade the product. The raw material preparation and impurity removal process requires the use of electromagnetic iron removers and rotary vibrating screens. Generally, the electromagnetic iron removers used by factories have a magnetic field strength between 10,000 and 30,000 gauss, and the number of rotary vibrating screens ranges from 180 to 325 meshes. The slurry is removed from the iron and screened in series to complete the raw material preparation process. At present, most bone china manufacturers have a raw material preparation process in which the slurry undergoes two iron removals and two screenings (such as Figure 1 As shown in the figure, a very small number of enterprises adopt the three-time iron removal and three-time screening process, which has the following disadvantages: (1) There are residual fine impurities in the slurry, and the residual amount is unstable as the impurity content in the raw materials changes, resulting in a yellowish color of the porcelain - fine iron impurities are colored and have poor light transmittance; (2) The magnetic field strength of the electromagnetic iron remover is between 10,000 and 30,000 gauss, which does not remove iron fully; (3) The recycled blank is ground into a slurry together with the formulated raw materials, mixed evenly, and then subjected to the iron removal and screening processes. The harmful impurities in the recycled blank are ground, which increases the difficulty of removing fine impurities. Summary of the invention

[0004] In order to solve the above problems, the present invention provides a method for removing impurities from bone china raw materials, comprising the following steps: Step 1: Use a 120-mesh graded screen to coarsely screen the mixed slurry; Step 2: Use a 180-mesh graded screen to perform preliminary fine screening on the mixed slurry after the initial screening; Step 3: Remove iron impurities through a seven-step progressive electromagnetic iron removal method.

[0005] The present invention improves the particle size of adsorption of fine iron-containing impurities through a seven-step progressive enhanced electromagnetic iron removal process, and prepares bone porcelain raw materials with ultra-low iron content (iron content ≤ 1‰). At the same time, the granular harmful impurities in the recovered blank are removed through the rotary vibration screening process to prevent them from being ground again, effectively reducing the difficulty of removing fine impurities. Among them, the progressive method of the present invention refers to a series of stage-enhanced electromagnetic iron removers and a step-by-step increase in mesh size to gradually improve the adsorption capacity and screening effect of iron impurities in a progressive manner, and each iron remover may have different magnetic field strengths and fluctuations to ensure that smaller iron impurities of different sizes can be removed. The progressive electromagnetic iron removal method can reduce material waste and equipment maintenance costs, and has good cost-effectiveness in the long run.

[0006] Furthermore, in step 1, the mixed slurry is processed by a ball mill, and the material of the mesh screen is stainless steel.

[0007] Furthermore, the mesh screen is in the shape of round holes.

[0008] Furthermore, the vibration intensity of the rotary vibrating screen in step 2 is 1.2 times that of the vibration intensity in step 1. The strength improvement is mainly due to the fact that the aperture size of the 180-mesh screen is 1.5 times smaller than that of the 120-mesh screen, and the corresponding specific surface area of ​​the particles to be sorted is larger. Increasing the vibration intensity can effectively improve the screening efficiency, and the 1.2-fold vibration intensity is the result of comprehensive consideration of the resonance characteristics of the screen and the overall stability of the equipment.

[0009] Furthermore, step 3 includes the following steps: Step 3-1. Use a 30,000 gauss variable electromagnetic iron remover to remove ferrous impurities from the mixed slurry. The variable magnetic field fluctuation can cause the ferromagnetic impurities inside the slurry to produce dynamic fluctuations, which can promote the disorder of the ferromagnetic impurities and create a certain agitation inside the slurry, thereby enhancing the separation effect of ferromagnetic impurities and non-magnetic materials. The impurities are pushed to the surface or edge of the slurry through the action of fluctuations, causing the ferromagnetic impurities to gather at the boundary.

[0010] Step 3-2: Use a 30,000 Gauss constant electromagnetic iron remover to remove ferrous impurities from the mixed slurry. The purpose of using a constant magnetic field iron remover is to efficiently adsorb the ferromagnetic impurities that gather at the boundary and surface after the action of the variable magnetic field through a stable electromagnetic iron remover. The stable electromagnetic characteristics can ensure that the ferromagnetic impurities after adsorption are not easy to fall off again, thereby improving the removal effect.

[0011] Step 3-3, use a 250-mesh graded rotary vibrating screen to finely grade and screen the particles after electromagnetic iron removal; Step 3-4: Use a 30,000 gauss variable electromagnetic iron remover to remove ferromagnetic impurities in the mixed slurry; Step 3-5: Use a 30,000 gauss constant electromagnetic iron remover to remove iron impurities in the mixed slurry; Step 3-6: Use a 325-mesh grading screen to ultra-finely screen the mixed slurry to remove impurity particles; Step 3-7: Use a 40,000 gauss constant electromagnetic iron remover to absorb heavier and finer ferromagnetic impurities, effectively capture and separate refined impurities, and absorb ferromagnetic particles; Step 3-8: Use a 325-mesh graded screen to remove impurities that have not been completely removed; Step 3-9: Use 30,000 Gauss constant electromagnetic iron remover to enhance iron removal; Step 3-10, use a 30,000 gauss constant electromagnetic iron remover to enhance iron removal. 30,000 gauss is repeated twice, and the first iron removal preferentially adsorbs impurities with strong ferromagnetism and larger particle size. As the adsorption amount accumulates, the surface adsorption capacity after the ferromagnetic impurities are aggregated will be reduced, which will cause some small-sized, weak ferromagnetic impurities in a mixed state to be unable to be well adsorbed on the surface for removal. Therefore, a further 30,000 gauss repeated adsorption process is adopted to further remove the impurities missed in the previous stage, which can significantly improve the impurity removal effect. The second time is mainly to remove the residual ferromagnetic properties and the missed impurities. At the same time, the repeated iron removal process with two constant low magnetic field strengths can not only reduce the heavy load of the equipment itself, but also reduce equipment wear and tear, and extend the service life of the equipment.

[0012] Furthermore, in step 3-1, the magnetic field intensity fluctuation of the 30,000 Gauss variable electromagnetic iron remover is ±15%. This is mainly because the particle size of the ferromagnetic impurities after the flowing slurry passes through the 120-mesh and 180-mesh rotary vibration screens is below 0.08 mm. When ferromagnetic impurities of this particle size are in a fluctuating non-uniform magnetic field, the size and direction of the magnetic field to which the particles are subjected changes with the position, resulting in an unbalanced force on the particles in the magnetic field. After analysis and experiments, the ±15% magnetic field intensity fluctuation will cause the ferromagnetic impurity particles to move more significantly toward high magnetic field intensity, making them easier to be captured and separated by magnetic separation.

[0013] Furthermore, in step 3-4, the magnetic field intensity of the 30,000 Gauss variable electromagnetic iron remover fluctuates by ±10%. The reason for adjusting the fluctuation to ±10% is that step 3-4 is based on step 3-1, and the particle size of the ferromagnetic impurities treated by the 250-mesh rotary vibration screen in step 3-3 is smaller. Therefore, according to the optimal non-equilibrium force movement mechanism of ferromagnetic impurities under the non-uniform magnetic field described in step 3-1, adjusting the magnetic field fluctuation intensity to ±10% is the best effect.

[0014] Furthermore, in step 5, the 325-mesh grading screen is a 325-mesh rotary vibrating screen.

[0015] Furthermore, the material of the 325-mesh grading screen is stainless steel.

[0016] Furthermore, the mesh surface of the 325 mesh grading screen is attached with dot-shaped spikes with a diameter of less than 3 microns, so as to filter out harmful material particles with a diameter of more than 40 microns, while significantly reducing the adhesion of the screen to the raw material, enhancing the filtering effect and efficiency. In addition, on the surface where the fluid flows, the round spikes help prevent the accumulation of dirt or sediment.

[0017] Beneficial effects of the present invention: (1) The present invention improves the magnetic field strength of the electromagnetic iron remover to 30,000 gauss or 40,000 gauss, thereby increasing the suction and removal of fine iron-containing impurities; the vibrating screen adopts a 325-mesh stainless steel screen and abandons a low-mesh screen, effectively screening out harmful material particles with a diameter of more than 40 microns.

[0018] (2) After many tests, the present invention found that it takes 7 passes of the electromagnetic iron remover and 5 passes of the rotary vibrating screen to completely remove the iron-containing impurities in the slurry.

[0019] (3) The recycled blanks contain large particles of impurities mixed in during the molding process, but no fine iron-containing impurities. Therefore, the recycled blanks are stirred with water in the material well to form slurry, and the slurry is passed through a rotary vibrating screen once to remove large particles of impurities. This avoids the large particles of impurities from being crushed, but directly screened out by the rotary vibrating screen. The recycled blank slurry is then mixed with the formula raw material slurry, and then passed through an electromagnetic iron remover 7 times and a rotary vibrating screen 5 times before reaching the next filtration process. This achieves complete and thorough removal of harmful impurities in the slurry.

[0020] Based on the above effects, the present invention has good application effect in the field of ceramic production technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the existing iron removal screening process.

[0022] Figure 2 It is a schematic diagram of the seven-filtration and five-screening process of the present invention.

[0023] Figure 3 It is a schematic diagram of the structure of a 325 mesh vibrating screen.

[0024] Figure 4 The ceramic is fired based on the raw materials prepared by the method of the present invention. DETAILED DESCRIPTION

[0025] In order to make the objectives, technical solutions and advantages of the present application more clearly understood, the present application is further described in detail below with reference to the accompanying drawings and examples.

[0026] The present invention provides a method for removing impurities from bone china raw materials, such as Figure 2 As shown. The method of the present invention mainly includes 3 main steps. In order to clearly illustrate the present invention, the 3 steps are described as follows: Step 1: Use a 120-mesh graded screen to coarsely screen the mixed slurry.

[0027] In this step, the mixed slurry prepared by the ball mill is coarsely screened through a 120-mesh stainless steel graded mesh screen to remove coarse particles. The 120-mesh stainless steel mesh screen is designed to have round holes, which increases the collision and refinement effect on the surface of irregular particles during the rotary vibration screening.

[0028] Step 2: Use a 180-mesh graded sieve to perform preliminary fine screening on the mixed slurry after the initial screening.

[0029] In this step, the mixed slurry after the initial screening is sent to a 180-mesh grading screen for preliminary fine screening, so that the mixed slurry achieves a more uniform particle size distribution; in this level of screening, the vibration intensity of the rotary vibrating screen is increased to 1.2 times the vibration intensity in step 1 to improve the efficiency of fine screening.

[0030] Step 3: Remove iron impurities through a seven-step progressive electromagnetic iron removal method.

[0031] The progressive method of the present invention refers to gradually improving the adsorption capacity and screening effect of iron impurities by a series of stage-by-stage enhancement of the electromagnetic iron remover and the gradual increase of the mesh size of the screen, and each iron remover may have different magnetic field strengths and fluctuations to ensure that smaller iron impurities of different sizes can be removed. This step includes the following 10 sub-steps.

[0032] Step 3-1: Use a 30,000 gauss variable electromagnetic iron remover to remove iron impurities from the mixed slurry.

[0033] The finely screened slurry is sent to a 30,000 gauss electromagnetic iron remover to remove iron impurities from the raw material. The electromagnetic iron remover at this level is set to a fluctuating magnetic field strength of ±15%. The variable magnetic field helps to treat the material more evenly, ensuring that all parts are properly iron-removed.

[0034] Step 3-2: Use a 30,000 gauss constant electromagnetic iron remover to remove iron impurities in the mixed slurry.

[0035] The mixed slurry treated in step 3-1 is sent to a 30,000 gauss constant electromagnetic iron remover to increase the attraction of ferromagnetic impurities, thereby improving the iron removal efficiency.

[0036] Step 3-3: Use a 250-mesh grading rotary vibrating screen to finely grade and screen the particles after electromagnetic iron removal.

[0037] The mixed slurry treated in step 3-2 is sent to a 250-mesh grading rotary vibrating screen to finely grade and screen the particles after primary electromagnetic iron removal.

[0038] Step 3-4: Use a 30,000 gauss variable electromagnetic iron remover to remove ferromagnetic impurities in the mixed slurry.

[0039] The mixed slurry screened in step 3-3 is passed through a 30,000 gauss electromagnetic iron remover to remove the ferromagnetic impurities. The magnetic field intensity fluctuation of this level of 30,000 gauss variable electromagnetic iron remover is ±10%. The lower fluctuation magnetic field can better adapt to the differences in ferromagnetic impurities of different fine particle types, thereby improving the flexibility and effect of iron removal.

[0040] Step 3-5: Use a 30,000 gauss constant electromagnetic iron remover to remove iron impurities in the mixed slurry.

[0041] The mixed slurry treated in step 3-4 is sent to a 30,000 gauss constant electromagnetic iron remover for progressive and enhanced iron removal.

[0042] Step 3-6: Use a 325-mesh grading screen to ultra-finely screen the mixed slurry to remove impurity particles.

[0043] The mixed slurry after the treatment in step 3-5 is passed through a 325 mesh grading screen to further ultra-finely screen and remove impurity particles. The 325 mesh grading screen is a 325 mesh rotary vibrating screen. The material of the 325 mesh grading screen is stainless steel. The mesh surface of the 325 mesh grading screen is attached with dot-shaped spikes with a diameter of less than 3 microns. Figure 3 This is a structural diagram of a 325-mesh stainless steel vibrating screen. The 325-mesh vibrating screen uses a stainless steel screen, and the mesh surface of the stainless steel screen is attached with dot-shaped spikes with a diameter of less than 3 microns. The shape of the spikes can reduce the adhesion of slurry raw materials on the surface of the screen, because the spikes break the continuous layer of slurry on the screen, making it difficult for impurities to adhere, thereby reducing the blockage of the screen pores, keeping the screen unobstructed, and extending the service life of the screen. In addition, the spikes can enhance the hydrophobicity of the screen and help drain the moisture on the surface of the screen. Especially when processing wet slurry, the spike design helps to more effectively separate the solid particles and liquid in the slurry and improve the separation efficiency.

[0044] Step 3-7: Use a 40,000 variable Gaussian iron remover to absorb heavier and finer ferromagnetic impurities, effectively capture and separate refined impurities, and absorb ferromagnetic particles.

[0045] The mixed slurry after fine screening in steps 3-6 is sent to a 40,000 variable iron remover to adsorb heavier and finer ferromagnetic impurities, thereby achieving effective capture of fine impurities and separation and adsorption of ferromagnetic particles.

[0046] Step 3-8: Use a 325-mesh graded sieve to remove impurities that have not been completely removed.

[0047] The mixed slurry after the treatment in steps 3-7 is sent to a 325-mesh grading screen for a second time to remove the impurities that have not been removed, thereby further removing and improving the purity of the slurry.

[0048] Step 3-9: Use 30,000 Gauss constant electromagnetic iron remover to enhance iron removal.

[0049] The mixed slurry after the treatment in step 3-8 is sent to a 30,000 gauss constant electromagnetic iron remover for enhanced iron removal.

[0050] Step 3-10: Use 30,000 Gauss constant electromagnetic iron remover to enhance iron removal.

[0051] The mixed slurry treated in steps 3-9 is repeatedly passed through a 30,000 Gauss constant electromagnetic iron remover for a second time to perform progressive and enhanced iron removal to improve the purity of the slurry.

[0052] Figure 4 It is a ceramic fired on the basis of the raw materials prepared by the method of the present invention. As can be seen from the figure, the ceramic fired by the method of the present invention is good in light transmittance, delicate and transparent in porcelain, and white and warm in color like jade, which significantly improves the grade of the product. In addition, the product quality is significantly improved, the mud defect is reduced from more than 1.2% to 0.2%, and the first-class rate of the product is increased by more than 1%. At present, the monthly output is 1.2 million pieces, and more than 12,000 first-class products are added each month. The company reduces costs and increases benefits by more than 50,000 yuan each month.

[0053] In summary, the present invention provides a method for removing impurities from bone china raw materials, including: step 1, using a 120-mesh graded mesh screen to preliminarily screen the mixed slurry; step 2, using a 180-mesh graded mesh screen to preliminarily finely screen the preliminarily screened mixed slurry; step 3, removing iron impurities through a seven-step progressive electromagnetic iron removal method. The present invention uses a "7-filter 5-screen" process, that is, the slurry passes through a high-intensity electromagnetic iron remover 7 times, passes through a high-mesh rotary vibrating screen 5 times, and removes iron impurities through a progressive electromagnetic iron removal method, achieving a relatively complete removal of harmful impurities. The ceramics prepared using these raw materials have good light transmittance, delicate and moist porcelain, and a white and warm color like jade, which significantly improves the product grade.

[0054] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application shall be included in the scope of protection of the present application.

Claims

1. A method for removing impurities from bone china raw materials, characterized in that: The steps include: Step 1: Use a 120-mesh graded rotary vibrating screen to coarsely screen the mixed slurry; Step 2: Use a 180-mesh graded rotary vibrating screen to perform preliminary fine screening on the mixed slurry after the initial screening; Step 3: Remove iron impurities through a seven-step progressive electromagnetic iron removal method.

2. The method for removing impurities from bone china raw materials according to claim 1, characterized in that: In step 1, the mixed slurry is processed by a ball mill, and the material of the mesh screen is stainless steel.

3. The method for removing impurities from bone china raw materials as claimed in claim 2, characterized in that: The mesh screen is in the shape of a circular hole.

4. The method for removing impurities from bone china raw materials as claimed in claim 3, characterized in that: The vibration intensity of the rotary vibrating screen in step 2 is 1.2 times the vibration intensity in step 1.

5. The method for removing impurities from bone china raw materials according to any one of claims 1 to 4, characterized in that: The step 3 comprises the following steps: Step 3-1, use a 30,000 gauss variable electromagnetic iron remover to remove iron impurities in the mixed slurry; Step 3-2: Use a 30,000 gauss constant electromagnetic iron remover to remove iron impurities in the mixed slurry; Step 3-3, use a 250-mesh graded rotary vibration screen to finely grade and screen the particles after electromagnetic iron removal; Step 3-4: Use a 30,000 gauss variable electromagnetic iron remover to remove ferromagnetic impurities in the mixed slurry; Step 3-5: Use a 30,000 gauss constant electromagnetic iron remover to remove iron impurities in the mixed slurry; Step 3-6: Use a 325-mesh graded rotary vibration screen to perform ultra-fine screening on the mixed slurry to remove impurity particles; Step 3-7: Use a 40,000 gauss constant electromagnetic iron remover to absorb heavier and finer ferromagnetic impurities, effectively capture and separate refined impurities, and absorb ferromagnetic particles; Step 3-8: Use a 325-mesh graded rotary vibration screen to remove impurities that have not been completely removed; Step 3-9: Use 30,000 Gauss constant electromagnetic iron remover to enhance iron removal; Step 3-10: Use 30,000 Gauss constant electromagnetic iron remover to enhance iron removal.

6. The method for removing impurities from bone china raw materials as claimed in claim 5, characterized in that: In step 3-1, the magnetic field intensity fluctuation of the 30,000 gauss variable electromagnetic iron remover is ±15%.

7. The method for removing impurities from bone china raw materials according to claim 6, characterized in that: In step 3-4, the magnetic field intensity fluctuation of the 30,000 gauss variable electromagnetic iron remover is ±10%.

8. The method for removing impurities from bone china raw materials as claimed in claim 7, characterized in that: In step 5, the 325-mesh grading screen is a 325-mesh rotary vibrating screen.

9. The method for removing impurities from bone china raw materials as claimed in claim 8, characterized in that: The material of the 325-mesh grading screen is stainless steel.

10. The method for removing impurities from bone china raw materials according to claim 9, characterized in that: The mesh surface of the 325-mesh grading screen is attached with dot-shaped spikes with a diameter less than 3 microns.

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