CN114835471A

CN114835471A - High white porcelain blank and manufacturing method thereof

Info

Publication number: CN114835471A
Application number: CN202210673513.3A
Authority: CN
Inventors: 高玉贵; 孟敬; 孟春和; 孟春雯; 冯博雅; 高娃
Original assignee: Inner Mongolia Longxing New Material Technology Co ltd
Current assignee: Inner Mongolia Longxing New Material Technology Co ltd
Priority date: 2022-06-14
Filing date: 2022-06-14
Publication date: 2022-08-02

Abstract

The application provides a high-whiteness porcelain blank and a manufacturing method thereof, wherein kaolin and bentonite are mixed to prepare a premix, the premix is purified to remove heavy sand and large granular substances in the premix, the fineness of slurry is improved, the contents of iron and titanium in the slurry are reduced, the purified premix is mixed with quartz, talc, feldspar and industrial alumina powder, fine grinding is carried out, the compatibility among all components is improved, a basic blank is prepared, and impurities are removed from the basic blank, so that the high-whiteness porcelain blank is prepared. The high-white porcelain blank prepared by the method has low iron and titanium contents, good lubricity and plasticity, and the advantages of high firing stability, good strength of semi-finished products and good transparency of finished products. In addition, the method also has the characteristic of high whiteness of the fired finished product.

Description

High white porcelain blank and manufacturing method thereof

Technical Field

The application relates to the technical field of ceramics, in particular to a high-whiteness porcelain blank and a manufacturing method thereof.

Background

A high-whiteness porcelain is made up of kaolin through deep processing and high-temp reduction firing. The porcelain glaze is pure, fine and smooth in color, high in cleanness and free of defects, and can be used for making the skin and the bone. The blank of the high-white porcelain is the key for firing the high-white porcelain, but the lubricity and plasticity of the existing blank of the high-white porcelain need to be further improved, so that the high-white porcelain prepared from the blank has the advantages of semi-finished product strength, firing stability and finished product transparency which need to be further improved.

Disclosure of Invention

The application provides a method for manufacturing a high-white porcelain blank, which is used for improving the lubricity and plasticity of the manufactured high-white porcelain blank.

The application also provides a high white porcelain blank for improving the firing stability, the semi-finished product strength and the transparency of the high white porcelain blank.

In a first aspect, the application provides a method for manufacturing a high-whiteness porcelain blank, which comprises the following steps:

uniformly mixing 65-75 parts of kaolin and 0.8-2 parts of bentonite according to parts by weight to prepare a premix;

purifying the premix to obtain a purified premix;

mixing 8-15 parts by weight of quartz, 5-10 parts by weight of talc, 3-8 parts by weight of feldspar and 4-7 parts by weight of industrial alumina powder with a purification premix to obtain a pre-blank, and finely grinding the pre-blank to obtain a basic blank;

and removing impurities from the basic blank to obtain the high-white porcelain blank.

According to the manufacturing method of the high-white porcelain blank, the raw materials of the high-white porcelain blank are sequentially subjected to purification, fine grinding, impurity removal and mud squeezing, so that the compatibility, lubricity and plasticity of the components of the high-white porcelain blank are improved, iron and titanium impurities in the components of the high-white porcelain blank are further removed through the impurity removal operation, and the whiteness of a finished product can be improved.

Alternatively, the purification comprises the following operations:

uniformly mixing the premix with water, and mashing to obtain a first slurry;

performing gravity suspension on the first slurry, and removing a precipitate layer to obtain a second slurry;

carrying out centrifugal purification on the second slurry to obtain centrifugal slurry;

carrying out iron and titanium removal operation on the centrifugal slurry to obtain iron and titanium removal slurry;

and dehydrating the slurry with iron and titanium removed to obtain the purified premix.

According to the manufacturing method of the high-whiteness porcelain blank, the premix is purified through the operations of slurry smashing, gravity suspension, centrifugal purification, iron and titanium removal and dehydration, the purity of the premix can be improved, the content of iron and titanium in the premix is reduced, and the whiteness of finished porcelain is improved.

Optionally, the mashing is: mixing premix and water at a weight ratio of W _{Premix compound} :W _{Water (W)} Mixing at the ratio of 1: 4-2: 3, and stirring at the stirring speed of 3200-3800 rpm for 6-8 h;

the gravity suspension is as follows: adding the first slurry into a sedimentation tank, and standing for 10-15 hours;

the centrifugal purification comprises the following steps: adding the second slurry into a centrifuge, and centrifuging to obtain slurry with the particle size of less than 2 microns, wherein the rotating speed of a rotary drum of the centrifuge is 3200-3800 rpm, and the differential rotating speed is 3-5%;

the iron and titanium removing operation comprises the following steps: adding the centrifugal slurry into a magnetic separator at a flow rate of 60-100 kg/h, and removing iron and titanium in the centrifugal slurry;

the dehydration is as follows: and adding the slurry for removing iron and titanium into a filter press, and carrying out filter pressing at the pressure of 0.5-0.7 MPa to obtain the purified premix.

Optionally, the fine milling is: putting the pre-blank and water into a ball mill according to the weight ratio of 1: 0.8-1.2, ball-milling for 48-60 h, and then sieving with a 325-mesh sieve to obtain a basic blank.

In the application, the premix, quartz, talc, feldspar and industrial alumina powder are mixed and then finely ground, so that a blank with a finer particle size can be obtained, the compatibility among the raw materials can be increased, the lubricity of the blank can be increased, and the transmittance of a finished product fired from the blank and the plasticity of the blank can be improved.

Optionally, removing impurities is: and adding the basic blank into a magnetic separator at a flow rate of 60-100 kg/h for magnetic separation, and removing iron and titanium in the centrifugal slurry to obtain the magnetic separation blank.

And squeezing the iron and titanium removing blank to obtain the high-whiteness porcelain blank.

Optionally, the pressed mud is: and adding the slurry for removing iron and titanium into a filter press, and carrying out filter pressing at the pressure of 0.5-0.7 MPa to obtain the high-whiteness porcelain blank.

Optionally, the water content in the purification premix is 28-32 wt%.

Optionally, the water content in the high-white porcelain blank is 28-32 wt%.

Optionally, the pre-blank further comprises 3-7 parts by weight of calcium phosphate.

In a second aspect, the present application provides a high white porcelain blank comprising a ceramic body obtained by the method of any one of the first aspect.

The high-white porcelain blank prepared by the method has low iron and titanium contents and good lubricity and plasticity, and the kaolin contained in the blank increases the plasticity of the blank; the feldspar can enhance the strength of the prepared blank; the bentonite as the adhesive can inhibit the deformation rate of the green body in the drying process and improve the strength of the semi-finished product; the addition of talc can enhance the whiteness and light transmittance of the fired finished product, and the addition of the industrial alumina powder can enhance the strength and deformation resistance of the prepared blank. The high-white porcelain blank provided by the application has the advantages of high firing stability, good strength of a semi-finished product, good transparency of a finished product and high whiteness.

The high-whiteness porcelain blank and the manufacturing method thereof provided by the application are characterized in that kaolin and bentonite are mixed to prepare a premix, the premix is purified to remove heavy sand and large-particle substances in the premix, the fineness of slurry is improved, the iron and titanium contents in the slurry are reduced, the purified premix is mixed with quartz, talc, feldspar and industrial alumina powder, fine grinding is carried out, the compatibility among the components is improved, a basic blank is prepared, impurities are removed from the basic blank, the iron and titanium contents in the basic blank are further reduced, and therefore the high-whiteness porcelain blank is prepared. According to the manufacturing method of the high-white porcelain blank, the raw materials of the high-white porcelain blank are sequentially subjected to purification, fine grinding, impurity removal and mud squeezing, so that the purity of the high-white porcelain blank can be improved, the compatibility, lubricity and plasticity of the components can be increased, and the characteristic of improving the whiteness of a finished product is achieved.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application are clearly and completely described below, and it is obvious that the described embodiments are a part of the embodiments of the present application, but not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

step one, uniformly mixing 65-75 parts of kaolin and 0.8-2 parts of bentonite by weight to prepare a premix;

step two, purifying the premix to obtain a purified premix;

mixing 8-15 parts by weight of quartz, 5-10 parts by weight of talc, 3-8 parts by weight of feldspar and 4-7 parts by weight of industrial alumina powder with the purification premix to obtain a pre-blank, and finely grinding the pre-blank to obtain a basic blank;

and step four, removing impurities from the basic blank and squeezing mud to obtain the high-whiteness porcelain blank.

The kaolin can ensure that the porcelain has good mechanical strength, thermal stability and chemical stability. In actual use, the kaolin is selected from Yunnan kaolin, Longyan kaolin or Jiepai kaolin with low contents of iron and titanium.

The function of feldspar in the blank: drying is accelerated, and drying shrinkage and deformation are reduced. The feldspar is used as a flux substance, so that the sintering temperature of the product can be reduced. When the feldspar is heated to 1100 ℃, the glass state substance generated after melting has the capacity of dissolving other substances, and can promote the mutual diffusion and the mutual permeation of the kaolin and the particles of other porcelain clay, so that the generation and the development of mullite crystals are accelerated. After the feldspar is melted into a glass state, the feldspar is filled among all crystal particles, so that the porosity is obviously reduced, the gaps are reduced, the blank is compact, and the mechanical strength of the product can be improved.

Quartz is a non-plastic raw material, so that drying shrinkage of a blank can be reduced, and deformation of the blank is prevented; the volume expansion generated by polycrystalline transformation of quartz at high temperature can partially offset the shrinkage generated during the firing of the blank, and the stress caused by large firing shrinkage is weakened, so that the firing performance is improved; in the process of sintering, the quartz is partially fused in the glass phase, so that the concentration of the liquid phase is improved, and the residual quartz forms the framework of the blank body, so that the blank body has the capability of resisting deformation at high temperature, and the mechanical strength of the blank body can be improved.

The introduction of the talc raw material increases the viscosity of the liquid phase of the blank in a high-temperature state, thereby being beneficial to widening the sintering range of the blank; the introduction of a small amount of talc raw material reduces the moisture absorption expansion of the green body; meanwhile, the semi-transparency of the blank can be improved by the talc; the talc having Mg therein ²⁺ Can be reacted with Fe ²⁺ To form a solid solution (Mg. FeO) ₃ (ii) a If it is TiO ₂ Then MgO & TiO is formed ₂ Thus adding Fe ² ⁺ And TiO ₂ Fixed to avoid Fe ²⁺ And TiO ₂ The combined action causes the condition that the whiteness of the finished porcelain is low, and simultaneously, the talc introduces Mg ²⁺ Has opacifying function and is also beneficial to improving the whiteness of products.

The bentonite is added into the blank of the porcelain, so that the blank of the porcelain product is not easy to crack in the drying and forming process, and the plasticity of the blank can be increased.

The addition of the industrial aluminum oxide can increase the solid phase quantity of the green body in a high-temperature state and reduce the proportion of the liquid phase quantity. Therefore, due to Al ₂ O ₃ The addition of the composition has good enhancing effect on the strength and the deformation resistance of the green body.

In the application, 65-75 parts of kaolin and 0.8-2 parts of bentonite are uniformly mixed to be used as a premix, because the kaolin and the bentonite are fine and close in texture, the kaolin and the bentonite are convenient to be mixed in advance, and the kaolin is the most in content in the blank, namely the kaolin is an essential raw material for manufacturing the high-whiteness porcelain blank; secondly, a series of phase changes and chemical changes occur to the kaolin in the firing process, so that the porcelain has good whiteness, mechanical strength, thermal stability and chemical stability; the bentonite is added as a binder, so that the instability of the green body in the forming process can be reduced; and secondly, the plasticity of the blank can be increased.

In the application, the purification can remove heavy sand and large particle substances in the premix, improve the fineness of the slurry, and reduce the contents of iron and titanium in the slurry, thereby improving the whiteness of the porcelain fired from the white porcelain blank.

In the application, the feldspar is added, so that the mechanical strength of the fired porcelain can be improved; the addition of quartz enables the green body to have the capability of resisting deformation at high temperature in the firing process, and can also improve the mechanical strength of the green body; the addition of the talc can improve the semi-transparency and whiteness of the fired porcelain; the addition of the industrial aluminum oxide has good enhancement effect on the strength and the deformation resistance of the green body. Therefore, quartz, talc, feldspar and industrial alumina powder are selected and mixed with the obtained purification premix according to a certain proportion: 8-15 parts of quartz, 5-10 parts of talc, 3-8 parts of feldspar and 4-7 parts of industrial alumina powder, and mixing to obtain a pre-blank.

In the application, the obtained pre-blank is finely ground, and the pre-blank is finely ground into the basic blank with smaller granularity and finer texture, so that the mixing process of the raw materials is realized while the pre-blank is finely ground, the compatibility of the raw materials can be increased, and the transparency and the quality of the white porcelain can be improved.

In this application, carry out the edulcoration operation with basic blank, the edulcoration helps reducing the content of iron, titanium in the blank to promote the blank and make the whiteness degree of finished product porcelain, and still press the mud operation, press the unnecessary moisture in the mud operation dischargeable blank, make the blank have certain water content, be convenient for make the body.

According to the manufacturing method of the high-whiteness porcelain blank, kaolin and bentonite are mixed to form the premix, the premix is purified to remove heavy sand and large-particle substances in the premix, the fineness of the slurry is improved, the iron and titanium contents in the slurry are reduced, the purified premix is mixed with quartz, talc, feldspar and industrial alumina powder, fine grinding is carried out, the compatibility among the components is improved, a basic blank is manufactured, impurities are removed from the basic blank, the iron and titanium contents in the basic blank are further reduced, and therefore the high-whiteness porcelain blank is manufactured. According to the manufacturing method of the high-white porcelain blank, the raw materials of the high-white porcelain blank are sequentially subjected to purification, fine grinding, impurity removal and mud squeezing, so that the purity of the high-white porcelain blank can be improved, and the compatibility, lubricity and plasticity of the components can be increased. In addition, the method also has the characteristic of improving the whiteness of the finished product.

Alternatively, the purification comprises the following operations:

and S1, uniformly mixing the premix with water, and mashing to obtain a first slurry.

In this application, the thick liquid of smashing makes premix disperse evenly in aqueous for the first thick liquids that make are more exquisite.

And S2, performing gravity suspension on the first slurry, and discarding a sediment layer to obtain a second slurry.

In the present application, gravity suspension can remove large-mass impurities such as sand and stone in the first slurry, so that the purity of the second slurry is higher.

And S3, carrying out centrifugal purification on the second slurry to obtain centrifugal slurry.

In this application, great particulate matter in the thick liquids that gravity suspension can not be removed can further be removed in the centrifugation purification, promotes the fineness of thick liquids, further promotes the purity of the centrifugal slurry who obtains.

S4, performing iron and titanium removal operation on the centrifugal slurry to obtain iron and titanium removal slurry.

In the application, the iron and titanium removing operation can remove iron and titanium associated with iron in the slurry, reduce the content of iron and titanium in the slurry and be beneficial to improving the whiteness of a fired product.

And S5, dehydrating the slurry with iron and titanium removed to obtain the purified premix.

In this application, the dehydration can remove unnecessary moisture in the thick liquids, the follow-up operation of being convenient for to the moisture of taking off can recycle once more among the dehydration process.

In the application, the premix and water are mixed and then are subjected to a pulping operation, and the premix and the water are mixed according to a weight ratio of W _{Premix compound} ∶W _{Water (W)} The premix can be fully dispersed by mixing according to the proportion of 1: 4-2: 3, and in the process of slurry tamping, the premix is stirred for 6-8 hours at the stirring speed of 3200-3800 rpm, and the high-speed stirring can ensure that the dispersion of the premix in water is more uniform, so that the separation of light substances (namely, main components of the premix, namely kaolin and bentonite) and precipitable substances with higher specific gravity (such as sand and stone and other impurities mixed in the raw materials of the premix) in the premix is facilitated, and the next gravity suspension operation is facilitated; in addition, the high-speed and long-time stirring enables the granularity of the premix to be finer and finer in the stirring process, and is beneficial to improving the quality of the finally prepared high-white porcelain blank.

In the application, the first slurry is added into a sedimentation tank to be kept stand, gravity suspension operation is carried out, kaolin and bentonite in the first slurry obtained after slurry smashing are completely dispersed, the first slurry is kept stand in the sedimentation tank, precipitable substances with large specific gravity (such as impurities mixed in the raw materials of the premix, such as sand and stone) in the first slurry are settled under the action of gravity, sediment at the bottom layer is discarded, and light suspension at the upper layer is taken to be subjected to next operation. Because the precipitable material granule in kaolin and the bentonite is tiny in this application, so need the time of stewing of a relatively long time to remove it, the time of stewing is 10 ~ 15h in this application, this is in order to guarantee that the precipitable material of as much as possible deposits, if the time of stewing is too long, then the composition loss of kaolin and bentonite in the thick liquids is great.

In this application, centrifugal purification is in adding the second thick liquids into centrifuge, and wherein centrifuge is horizontal spiral shell centrifuge, and the second thick liquids are added to centrifuge drum in with 3200 ~ 3800 rpm's rotational speed centrifugation, collect the thick liquids that upper granularity is less than 2 μm, abandon the impurity that lower floor's granule is greater than 2 μm, and centrifugal purification can further remove great particulate matter in the thick liquids, promotes the fineness of thick liquids, further promotes the purity of the centrifugal thick liquids that obtains. The differential rotation speed is 3-5%, and in actual use, if the materials are high in viscosity and difficult to separate, a higher differential rotation speed is needed; if material viscidity is little, the big easy sedimentation of granule separates, can select the less poor rotational speed of using, select for use 3 ~ 5% in this application can guarantee the handling capacity, can guarantee the effect of centrifugal purification again.

In the absence of TiO ₂ In the case of (1), Fe in porcelain ₂ O ₃ Even if the content reaches 0.5%, the color development of the porcelain is not affected. Only in Fe ₂ O ₃ And TiO ₂ When existing at the same time, the color of the product is influenced. For example: 1% of TiO ₂ Same 0.4% Fe ₂ O ₃ In combination, the porcelain contains 0.7 percent of Fe in a color ratio ₂ O ₃ Without TiO ₂ It is strong. This is because the following compounds are formed depending on the ratio of oxides, the firing temperature of porcelain and the strength of firing reducing atmosphere: dark gray iron titanate (Fe) ₂ O ₃ ·TiO ₂ ) Black ilmenite (FeO. TiO) ₂ ) Black spinel (FeO. Fe) ₂ O ₃ ) And light gray 2Fe ₂ O ₃ ·TiO ₂ A compound of the formula (I). These compounds impart a yellowish or grayish hue to porcelainThe whiteness and transmittance of porcelain are lowered, and Fe is often contained in the raw material of high-whiteness porcelain ₂ O ₃ And TiO ₂ And the coexistence makes it necessary to reduce the iron and titanium contents in the blank to improve the whiteness of the finished high-whiteness porcelain.

In the application, the centrifugal slurry is added into the magnetic separator, and magnetic substances, mainly iron and Fe, in the centrifugal slurry are separated by utilizing the magnetic force of the magnetic separator ₃ O ₄ And with Fe ₃ O ₄ Associated TiO-containing compounds ₂ And (4) removing minerals. Because the blank contains iron and Fe in the firing process of the high white porcelain ₃ O ₄ Will generate Fe ₂ O ₃ ，Fe ₂ O ₃ And TiO ₂ The combined action can lead the color of the fired high white porcelain to be red and yellow, seriously affect the whiteness of the high white porcelain and reduce the quality of the high white porcelain. The centrifugal slurry is added into a magnetic separator at a flow rate of 60-100 kg/h, so that the treatment capacity can be ensured, and iron and titanium in the centrifugal slurry can be sufficiently removed. In practical operation, the operation of removing iron and titanium can be repeated for a plurality of times, so as to achieve better effect of removing iron and titanium.

In the application, the dehydration step is to add the slurry with iron and titanium removed into a filter press, and filter-press is carried out under the pressure of 0.5-0.7 MPa, so that the water content of the purified premix obtained after dehydration can reach the preset content range, and the purified premix is ensured to have certain wettability and is convenient for subsequent operation.

Optionally, the water content in the purified premix is 28-32 wt%.

In the application, the dehydration operation is to remove redundant water in the blank, and the removed water can be continuously added into the step needing water for continuous use, so that the waste of water resources can be avoided, the water content in the purified premix obtained after dehydration is 28-32 wt%, the purified premix keeps certain humidity, and the subsequent fine grinding operation is facilitated.

Optionally, the fine milling is: putting the pre-blank and water into a ball mill according to the weight ratio of 1: 0.8-1.2, ball-milling for 48-60 h, and sieving with a 325-mesh sieve to obtain a basic blank.

In the application, the fine grinding is to obtain the basic blank with smaller granularity and finer texture, the quality of the prepared high-white porcelain blank is further improved, the texture of the basic blank is finer, the whiteness of the porcelain blank obtained by firing is higher, and the transparency of the porcelain blank is also higher, so that the quality of the high-white porcelain blank is improved, and the long-time fine grinding (ball milling for 48-60 h in the application) is not only used for crushing the components in the blank, but also has the effects of stirring and mixing, so that the fine grinding for 48-60 h in the application is beneficial to improving the compatibility of the components in the blank, and is beneficial to improving the transparency of the fired porcelain. The first step of sieving with a 325-mesh sieve is to filter out large granular substances in the basic blank and improve the fineness of the slurry, so that the materials in the basic blank are kept at a certain granularity level (the granularity is smaller than the 325-mesh sieve in the application); and secondly, detecting whether the granularity of the basic blank and the fine grinding process reach the standard or not.

In the application, the pre-blank and water are put into a ball mill according to the weight ratio of 1: 0.8-1.2 for ball milling, and the water with the weight 0.8-1.2 times of that of the pre-blank is added, so that the pre-blank can be uniformly dispersed, and the effect of ball milling is promoted.

In the application, the magnetic separation operation is the same as the iron and titanium removing operation, and the purpose is to remove iron and titanium associated with iron in the corresponding blank so as to reduce the iron and titanium content in the blank and improve the whiteness of the finished product.

In this application, press the mud operation and also carry out the filter-pressing with the magnetic separation blank, detach unnecessary moisture in the magnetic separation blank, the moisture of press filter simultaneously can retrieval and utilization once more.

Optionally, the water content in the high-white porcelain blank is 28-32 wt%.

The high white porcelain blank keeps a certain content of moisture, 28-32 wt% in the application, so that the high white porcelain blank can be conveniently made into a required blank, if the moisture content is too high (greater than 32 wt%), the blank is too soft and is not easy to form, and if the moisture content is too low (less than 28 wt%), the made blank is easy to crack.

The addition of calcium phosphate can improve the whiteness of the fired porcelain because a silicate glass phase is generated in the firing process of the high-white porcelain, and the high-white porcelain adopts a reduction firing method to ensure that Fe is generated in the firing process of the high-white porcelain ₂ O ₃ Is reduced to Fe ²⁺ To reduce Fe ₂ O ₃ Yellow color brought by the reaction, and in the silicate glass phase, even if a small amount of Fe is contained ²⁺ Also cyan, and Fe in phosphate ²⁺ The color is colorless when the amount reaches 2-3%; trace amount of Fe ³⁺ In the silicic acid glass phase with [ FeO ₄ ]The tetrahedra present has a strong coloring power, and in the phosphate glass phase, it forms [ FeO ₈ ]Octahedron, with little tinting power. Therefore, a certain amount of phosphate is added into the pre-blank to improve the whiteness of the finished high-whiteness porcelain.

In a second aspect, the present application provides a high white porcelain blank, obtainable by the method of any one of the above first aspects.

The high-white porcelain blank prepared by the method has low iron and titanium contents and good lubricity and plasticity, and the kaolin contained in the blank increases the plasticity of the blank; the feldspar can enhance the strength of the prepared blank; the bentonite as the adhesive can inhibit the deformation rate of the green body in the drying process and improve the strength of the semi-finished product; the addition of talc can enhance the whiteness and light transmittance of the fired finished product, and the addition of the industrial alumina powder can enhance the strength and deformation resistance of the prepared blank. The high-white porcelain blank provided by the application has the advantages of high firing stability, good strength of a semi-finished product and good transparency of a finished product. In addition, the method also has the advantage of high whiteness.

Example 1

A high-white porcelain blank is prepared by the following steps:

(1) according to the weight portion, 70 portions of kaolin and 1 portion of bentonite are evenly mixed to prepare the premix.

(2) Mixing the premix and water according to the weight ratio of W _{Premix compound} ∶W _{Water (W)} The first ratio was mixed homogeneously 2:3 and stirred at 3600rpm for 6h to give a first slurry.

(3) And adding the first slurry into a sedimentation tank, standing for 10 hours, and discarding a sediment layer to obtain a second slurry.

(4) Adding the second slurry into a centrifuge, and centrifuging to obtain slurry with the particle size of less than 2 mu m to obtain centrifugal slurry; wherein the rotating speed of a rotary drum of the centrifuge is 3600rpm, and the differential rotating speed is 5 percent.

(5) Adding the centrifugal slurry into a magnetic separator at a flow rate of 80kg/h, and removing iron and titanium in the centrifugal slurry to obtain iron and titanium removed slurry.

(6) Adding the slurry with iron and titanium removed into a filter press, and carrying out filter pressing at the pressure of 0.6MPa to obtain a purified premix; the water content in the purification premix was 30 wt%.

(7) Mixing 10 parts by weight of quartz, 8 parts by weight of talcum, 5 parts by weight of feldspar, 6 parts by weight of industrial alumina powder and a purification premix to obtain a pre-blank, and mixing the pre-blank and water according to a mass ratio W _{Preliminary blank} ∶W _{Water (W)} Mixing the materials according to the proportion of 1: 1, adding the mixture into a ball mill, and carrying out ball milling and crushing for 58 hours to obtain a base blank.

(8) And (3) sieving the basic blank by a 325-mesh sieve, adding the basic blank into a magnetic separator at a flow rate of 80kg/h, and removing iron and titanium in the basic blank to obtain the magnetic separation blank.

(9) And then adding the magnetic separation blank into a filter press, and carrying out filter pressing at the pressure of 0.6MPa to obtain a high-whiteness porcelain blank with the water content of 30 wt%.

Example 2

A high-white porcelain blank is prepared by the following steps:

(1) according to the weight portion, 65 portions of kaolin and 2 portions of bentonite are evenly mixed to prepare the premix.

(2) Mixing the premix and water according to the weight ratio of W _{Premix compound} ∶W _{Water (W)} The first slurry was obtained by mixing homogeneously at a first ratio of 1:4 and stirring at 3800rpm for 6 h.

(3) And adding the first slurry into a sedimentation tank, standing for 15h, and discarding a sediment layer to obtain a second slurry.

(4) Adding the second slurry into a centrifuge, and centrifuging to obtain slurry with the particle size of less than 2 mu m to obtain centrifugal slurry; wherein the rotating speed of the rotary drum of the centrifuge is 3800rpm, and the differential rotating speed is 5%.

(5) Adding the centrifugal slurry into a magnetic separator at a flow rate of 60kg/h, and removing iron and titanium in the centrifugal slurry to obtain iron and titanium removed slurry.

(6) Adding the slurry with iron and titanium removed into a filter press, and carrying out filter pressing at the pressure of 0.5MPa to obtain a purified premix; the water content in the purification premix was 32 wt%.

(7) Mixing 12 parts by weight of quartz, 10 parts by weight of talcum, 3 parts by weight of feldspar, 4 parts by weight of industrial alumina powder and a purification premix to obtain a pre-blank, and mixing the basic blank and water according to a mass ratio W _{Preliminary blank} ∶W _{Water (W)} Mixing the materials according to the proportion of 1:0.8, adding the mixture into a ball mill, and carrying out ball milling and crushing for 48 hours to obtain a base blank.

(8) And (3) after the basic blank is sieved by a 325-mesh sieve, adding the basic blank into a magnetic separator at a flow rate of 60kg/h, and removing iron and titanium in the basic blank to obtain the magnetic separation blank.

Example 3

A high-white porcelain blank is prepared by the following steps:

(1) according to the weight portion, 75 portions of kaolin and 0.8 portion of bentonite are evenly mixed to prepare the premix.

(2) Mixing the premix and water according to the weight ratio of W _{Premix compound} ：W _{Water (W)} The first ratio was mixed homogeneously 2:3 and stirred at 3200rpm for 7h to give a first slurry.

(3) And adding the first slurry into a sedimentation tank, standing for 12 hours, and discarding a sediment layer to obtain a second slurry.

(4) Adding the second slurry into a centrifuge, and centrifuging to obtain slurry with the particle size of less than 2 mu m to obtain centrifugal slurry; wherein the rotating speed of a rotary drum of the centrifuge is 3200rpm, and the differential rotating speed is 5 percent.

(6) Adding the slurry with iron and titanium removed into a filter press, and carrying out filter pressing at the pressure of 0.7MPa to obtain a purified premix; the water content in the purified premix was 28 wt%.

(7) Mixing 8 parts by weight of quartz, 5 parts by weight of talcum, 6 parts by weight of feldspar, 5 parts by weight of industrial alumina powder and a purification premix to obtain a pre-blank, and mixing the pre-blank and water according to a mass ratio W _{Preliminary blank} ∶W _{Water (W)} Mixing the materials according to the proportion of 1: 1.2, adding the mixture into a ball mill, and carrying out ball milling and crushing for 50 hours to obtain a base blank.

(9) And then adding the magnetic separation blank into a filter press, and carrying out filter pressing at the pressure of 0.5MPa to obtain a high white porcelain blank with the water content of 32 wt%.

Example 4

A high-white porcelain blank is prepared by the following method:

(1) 67 parts of kaolin and 1.5 parts of bentonite are uniformly mixed according to the parts by weight to prepare the premix.

(2) Mixing the premix and water according to the weight ratio of W _{Premix compound} ：W _{Water (W)} The first ratio was mixed homogeneously at 1:4 and stirred at 3400rpm for 8h to give a first slurry.

(4) Adding the second slurry into a centrifuge, and centrifuging to obtain slurry with the particle size of less than 2 mu m to obtain centrifugal slurry; wherein the rotating speed of a rotary drum of the centrifuge is 3400rpm, and the differential rotating speed is 3-5%.

(5) Adding the centrifugal slurry into a magnetic separator at the flow rate of 90kg/h, and removing iron and titanium in the centrifugal slurry to obtain iron and titanium removed slurry.

(7) Mixing 10 parts by weight of quartz, 7 parts by weight of talcum, 8 parts by weight of feldspar, 6 parts by weight of industrial alumina powder and a purification premix to obtain a pre-blank, and mixing the pre-blank and water according to a mass ratio W _{Preliminary blank} ∶W _{Water (W)} Mixing at the ratio of 1: 1.1: and adding into a ball mill for ball milling and crushing for 55h to prepare a base blank.

(8) And (3) sieving the basic blank by a 325-mesh sieve, adding the basic blank into a magnetic separator at a flow rate of 90kg/h, and removing iron and titanium in the basic blank to obtain the magnetic separation blank.

Example 5

A high-white porcelain blank is prepared by the following method:

(1) according to the weight portion, 72 portions of kaolin and 1.2 portions of bentonite are evenly mixed to prepare the premix.

(2) Mixing the premix and water according to the weight ratio of W _{Premix compound} ：W _{Water (W)} The first ratio was mixed homogeneously 2:3 and stirred at 3600rpm for 8h to give a first slurry.

(5) Adding the centrifugal slurry into a magnetic separator at the flow rate of 100kg/h, and removing iron and titanium in the centrifugal slurry to obtain iron and titanium removed slurry.

(7) Mixing 15 parts by weight of quartz, 9 parts by weight of talcum, 5 parts by weight of feldspar, 7 parts by weight of industrial alumina powder and a purification premix to obtain a pre-blank, and mixing the pre-blank with waterIn mass ratio of W _{Preliminary blank} ∶W _{Water (W)} Mixing the materials according to the proportion of 1: 1.2, adding the mixture into a ball mill, and carrying out ball milling and crushing for 60 hours to obtain a base blank.

(8) And (3) after the basic blank is sieved by a 325-mesh sieve, adding the basic blank into a magnetic separator at the flow rate of 75kg/h, and removing iron and titanium in the basic blank to obtain the magnetic separation blank.

(9) And then adding the magnetic separation blank into a filter press, and carrying out filter pressing at the pressure of 0.7MPa to obtain a high white porcelain blank with the water content of 28 wt%.

Example 6

A high-white porcelain blank is prepared by the following steps:

the rest of the operation of this example is exactly the same as example 5, except that 3 parts by weight of calcium phosphate are also added in step (7) to mix with the basic batch.

Comparative example 1

A high-white porcelain blank is prepared by the following steps:

(2) Mixing 15 parts by weight of quartz, 9 parts by weight of talcum, 5 parts by weight of feldspar, 7 parts by weight of industrial alumina powder and premix to obtain a pre-blank, and mixing the pre-blank and water according to the mass ratio of W _{Preliminary blank} ∶W _{Water (W)} Mixing the materials according to the proportion of 1: 1.2, adding the mixture into a ball mill, and carrying out ball milling and crushing for 60 hours to obtain a base blank.

(3) And (3) after the basic blank is sieved by a 325-mesh sieve, adding the basic blank into a magnetic separator at the flow rate of 75kg/h, and removing iron and titanium in the basic blank to obtain the magnetic separation blank.

(4) And then adding the magnetic separation blank into a filter press, and carrying out filter pressing at the pressure of 0.7MPa to obtain a high white porcelain blank with the water content of 28 wt%.

Comparative example 2

A high-white porcelain blank is prepared by the following method:

the rest of the operation of this example is identical to that of example 5, except that in step (7) the ball milling time is 8 h.

Experimental example 1

The high white porcelain blanks obtained in the above examples 1 to 6 and comparative example 1 were subjected to composition analysis, and the results are shown in table 1:

TABLE 1

As can be seen from the data of examples 1 to 6 in table 1, the content of ferric oxide in the high-white porcelain blank prepared by the method of the present application is below 0.27%, and the content of titanium dioxide is below 0.06%, which indicates that the high-white porcelain blank prepared by the method of the present application has low iron and titanium contents, and has a positive significance for improving the whiteness of the finished porcelain, and the high-white porcelain blank prepared by the method of the present application has a small percentage of thermal weight loss, which indicates that the volatile content in the blank is small, which is beneficial to reducing the deformation rate of the blank during the firing process and improving the firing stability of the blank.

In contrast, comparative example 1 has no purification operation, the thermal weight loss ratio reaches 6.74%, and the iron and titanium contents are high, wherein the iron content is higher than 0.5%, and the titanium content is higher than 0.1%, and the whiteness of the fired finished porcelain is affected by the iron and titanium, and the color, luster and whiteness of the finished porcelain are inferior to those of examples 6 to 6.

Experimental example 2

Performance testing of high-whiteness ceramic blanks

The high white porcelain blanks prepared in the above examples 1 to 6 and the comparative example 2 are made into bowl blanks with the caliber of 120 to 125mm, 100 bowl blanks are manufactured in each example, and after drying in the shade, the bowl blanks are heated and reduced and fired by the following method:

(1) placing the bowl blanks dried in the shade in the embodiments 1 to 6 in a kiln, and uniformly heating the bowl blanks from room temperature to 400 ℃ for 3h and from 400 ℃ to 800 ℃ for 4 h; when the composition is used again, the temperature is uniformly raised from 800 ℃ to 1270 ℃ for 5h, the temperature is kept at 1270 ℃ for 5h, and then the fire is stopped.

(2) After stopping the fire, the temperature of the kiln is naturally reduced from 1270 ℃ to 200 ℃, the kiln is opened, the fired bowl is taken out, the bowl is cooled to the room temperature, and the yield is measured, and the result is shown in table 2.

Bowls made of the high-white porcelain blanks prepared in the examples 1-6 and the comparative examples 1 and 2 are measured by a method in GB/T3532-2009 daily porcelain, and 50 bowls in the finished product bowls are randomly selected for measurement of whiteness, deformation rate and water absorption, and the results are shown in Table 3; and the transmittance of bowls made of the high white porcelain blanks obtained in examples 1 to 6 and comparative examples 1 and 2 was evaluated. The results are shown in Table 4.

TABLE 2

Numbering	Number of finished products/piece	Percent of yield%
			Example 1	97	97
Example 2	98	98
			Example 3	98	98
Example 4	99	99
			Example 5	99	99
Example 6	99	99
			Comparative example 2	90	90

As can be seen from table 2, the high-white porcelain blank obtained by the method of the present application has a high yield in the firing process of the blank made of the blank, which indicates that the firing stability is high. The finished product rate of the porcelain fired from the blank prepared in the comparative example 2 is only 90%, which shows that the raw materials in the blank are low in compatibility and poor in blank lubricity without long-time (48-60 h) ball milling, so that the firing stability of the blank is negatively affected to a certain extent.

TABLE 3

As can be seen from the examples 1 to 6 in Table 3, after the high-whiteness porcelain blank prepared by the method is fired into a finished porcelain, the whiteness of the finished porcelain is over 85 and reaches the whiteness of a first-grade porcelain, which indicates that the whiteness is high, and the water absorption rate is low and is not more than 0.10 percent, which indicates that the finished porcelain has a compact surface, a high glass body content, and a high glass body content, which also indicates that the light transmittance of the porcelain is high. The number of the caliber deformation rate of less than or equal to 1.0 percent in 50 samples is more than 47, which shows that the green body has high firing stability, good mechanical strength and difficult deformation in the firing process. As can be seen from the comparison between example 5 and example 6, the addition of calcium phosphate to the ingot with high iron and titanium contents is beneficial to improving the whiteness of the fired finished product.

As can be seen from the data of comparative example 1, the whiteness of the porcelain fired from the blank obtained without the purification step was only 68, while the water absorption thereof was 0.11%, indicating that the whiteness of the porcelain fired from the blank obtained without the purification step was low; as can be seen from the data of comparative example 2, the whiteness of the porcelain made from the billet which was not ball-milled for a long time was slightly decreased, and the surface was not dense. High water absorption indicates that the porcelain has low vitreous body content and rough surface.

TABLE 4

Numbering	Transmittance/%)
		Example 1	53
Example 2	54
		Example 3	52
Example 4	53
		Example 5	53
Example 6	53
		Comparative example 1	48
Comparative example 2	44

Finally, the transmittance of the finished porcelain in the embodiments 1 to 6 is evaluated, and the result shows that the transmittance of the porcelain fired from the high white porcelain blank prepared by the method is 52 to 54 percent, which indicates that the transmittance is good.

The light transmittance of the porcelain prepared in the comparative example 1 is less than 50%, which shows that the porcelain prepared without blank purification has low transparency, and the light transmittance of the porcelain prepared in the comparative example 2 is 44%, which shows that the blank not milled for a long time has low transparency, and the blank not milled for a long time has coarse granularity and poor lubricity.

Finally, it should be noted that the above embodiments are only used for illustrating the technical solutions of the present application, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, it will be understood by those skilled in the art; the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present application.

Claims

1. The manufacturing method of the high-white porcelain blank is characterized by comprising the following steps of:

purifying the premix to obtain a purified premix;

and removing impurities and squeezing mud from the basic blank to obtain the high-whiteness porcelain blank.

2. The method for manufacturing a high-whiteness porcelain blank according to claim 1, wherein the purification comprises the following operations:

uniformly mixing the premix with water, and mashing to obtain a first slurry;

and dehydrating the slurry for removing iron and titanium to obtain the purified premix.

3. The method for manufacturing high white porcelain blank according to claim 2, wherein the slurry is prepared by the following steps: mixing the premix and water according to the weight ratio of W _{Premix compound} :W _{Water (W)} Mixing at the ratio of 1: 4-2: 3, and stirring at the stirring speed of 3200-3800 rpm for 6-8 h;

the dehydration comprises the following steps: and adding the slurry for removing iron and titanium into a filter press, and carrying out filter pressing at the pressure of 0.5-0.7 MPa to obtain the purified premix.

4. The method for manufacturing the high-whiteness porcelain blank according to claim 1, wherein the fine grinding is as follows: and putting the pre-blank and water into a ball mill according to the weight ratio of 1: 0.8-1.2, ball-milling for 48-60 h, and sieving with a 325-mesh sieve to obtain a basic blank.

5. The method for manufacturing the high-whiteness porcelain blank according to claim 1, wherein the impurity removal is as follows: and adding the basic blank into a magnetic separator at a flow rate of 60-100 kg/h for magnetic separation, and removing iron and titanium in the centrifugal slurry to obtain the magnetic separation blank.

6. The method for manufacturing the high-whiteness porcelain blank according to claim 5, wherein the squeeze mud is: and adding the magnetic separation blank into a filter press, and carrying out filter pressing at the pressure of 0.5-0.7 MPa to obtain a high-whiteness porcelain blank.

7. The method for manufacturing the high-whiteness porcelain blank according to claim 1 or 3, wherein the water content in the purified premix is 28-32 wt%.

8. The method for manufacturing the high-white porcelain blank according to claim 1 or 6, wherein the moisture content in the high-white porcelain blank is 28-32 wt%.

9. The method for manufacturing a high-whiteness porcelain blank according to claim 1 or 4, wherein the pre-blank further comprises 3-7 parts by weight of calcium phosphate.

10. A high-white porcelain blank characterized by being produced by the method for producing a high-white porcelain blank according to any one of claims 1 to 9.