CN109534785B - Artificial spherical ceramic composite sand - Google Patents
Artificial spherical ceramic composite sand Download PDFInfo
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- CN109534785B CN109534785B CN201811606338.6A CN201811606338A CN109534785B CN 109534785 B CN109534785 B CN 109534785B CN 201811606338 A CN201811606338 A CN 201811606338A CN 109534785 B CN109534785 B CN 109534785B
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Abstract
The invention relates to ceramic sand for castingThe field is artificial spherical ceramic composite sand which can be widely applied to molding materials in the industries of common sand casting, shell mold casting, precision casting and the like. The structure of the ceramic composite sand is mainly divided into an inner layer and an outer layer, and the inner core adopts powder with a larger grain diameter: one or more of nickel tailing slag, coal gangue and fly ash, wherein the outer layer adopts powder with a fine particle size: one or more of flint clay, bauxite and corundum. The grain diameter of the core powder is required to be D50Not more than 25 mu m, the grain diameter of the bauxite powder on the outer layer is required to be D50Less than or equal to 13 mu m. The obtained ceramic composite sand has good surface quality, excellent performance, high refractoriness and low breakage rate, and can be used for producing non-ferrous alloy castings, iron castings and steel castings.
Description
Technical Field
The invention relates to the field of ceramic sand for casting, in particular to artificial spherical ceramic composite sand which can be widely applied to molding materials in the industries of common sand casting, shell mold casting, precision casting and the like.
Background
Since WTO was added, the casting yield in China is steadily increasing, China is undoubtedly the first major casting country in the world, and with the improvement of casting quality, because of certain characteristics of silica sand, for example: the angle coefficient is large, the thermal expansion rate is large, and the like, and obviously the requirements of the casting industry are not met, and for example: the high-quality natural sand such as zircon sand, chromite sand and the like has limited reserves and high price, and the application of the high-quality natural sand is limited. On the other hand, the traditional sand casting method has poor regeneration performance and great damage to resources and environment because a large amount of silica sand is adopted, and the artificial spherical sand used as casting raw sand has excellent performance, is low in price compared with zircon sand, is easy to regenerate, saves resources and is green and environment-friendly. The first appearance of ceramic sand is shale ceramsite fired by a rotary kiln by American Rehmannide, which is widely applied to industries such as buildings, bridges and the like during the period of the second war, and the ceramsite is widely applied to industries such as petroleum fracturing propping agents, sewage treatment and the like in recent decades, for example: patent publication No. CN 105152629A discloses a ceramic sand for oil fracturing proppant, which is a basalt ceramic sand, and the main components of the ceramic sand comprise: 30-70% of bauxite, 5-15% of basalt, 5-10% of manganese powder, 5-15% of ceramic grinding waste and 15-30% of clay, wherein the ceramic grain sand has large component change, larger performance difference and lack of improvement of surface quality, and although the performance of the ceramic grain sand can meet the use as a petroleum fracturing propping agent, the requirement of sand for casting is difficult to meet.
In recent years, some manufacturers originally used as ceramsite oil fracturing propping agents begin to apply the ceramsite produced by the manufacturers to casting molding materials, such as: flint clay ceramic sand produced by Shandong Diamond New materials GmbH. There are also some traditional molding material manufacturing enterprises that are beginning to deal with sintered ceramic sand for casting, such as: ceramic sand for casting produced by Shandong Shengquan New Material Co. There is also a group of patents filed by enterprises and scientific institutions, for example: patent publication No. CN105344919A discloses a ceramic sand for casting molding materials, the main component of which is SiO2The ceramic sand for casting is low-aluminum or even aluminum-free ceramic sand, and comprises the following components: based on the weight of the ceramic sand as 100 percent, the ceramic sand contains 5 to 44.5 weight percent of Al2O355 to 94.5 weight percent of SiO2And the balance other materials. Its advantages are low content of Al or even no Al, and low cost. But the defects are obvious because the raw materials are low-aluminum or even non-aluminum materials, the refractoriness is poor, the performance is general, and the method is suitable for the modeling material used by the casting of the low-melting-point alloy and can not be used for the modeling of the casting (such as high manganese steel and the like) with the temperature of more than 1600 ℃; in order to meet the performance requirements of high-melting-point alloy casting production on raw sand, casting sand with high refractoriness, small thermal expansion coefficient and good particle roundness must be designed to improve the casting quality and promote the development of the casting industry. Patent publication No. CN107298584A discloses a ceramic sand for casting molding materials, which comprises the following components: SiO 2235-65% of Al2O330-50% of Fe2O31-10% of MnO21-4% of Cr2O3The content of the aluminum or aluminum-free ceramsite sand is 2-8%, the refractoriness of the aluminum or aluminum-free ceramsite sand is improved, but the sintering temperature is up to 1550-1700 ℃, the sintering time is 3.5-5 hours, the sintering temperature is too high, the heat preservation time is too long, the energy is wasted, the cost is increased, and the roasting temperature of the conventional sintering rotary kiln is not as high as the sintering temperature of the conventional sintering rotary kilnTemperature, there is a major technical bottleneck. Therefore, designing a casting sand with low sintering temperature, high refractoriness, small thermal expansion coefficient, good particle roundness and low cost is an important problem to be solved urgently in the field of molding materials.
Disclosure of Invention
Aiming at the technical problems in the field of the existing ceramic sand for casting, the invention aims to provide the artificial spherical ceramic composite sand which has high refractoriness, low sintering temperature, low cost and excellent performance, can replace the original ceramic sand with a single structure, and meets the requirement of actual casting production.
In order to realize the purpose of the invention, the technical scheme is as follows:
the structure of the artificial spherical ceramic composite sand is mainly divided into an inner layer and an outer layer, and the inner core adopts main powder with a coarser grain diameter as follows: one or more than two of nickel tailing slag, coal gangue and fly ash, wherein the outer layer adopts main powder with smaller grain size as follows: one or more of flint clay, bauxite and corundum; wherein the grain diameter of the core powder is required to be D50Not more than 25 mu m, the grain diameter of the bauxite powder on the outer layer is required to be D50≤13μm。
The artificial spherical ceramic composite sand is preferably selected, and the particle size of the inner core powder is not less than 13D50Less than or equal to 25 mu m, and the grain diameter of the powder material at the outer layer is less than or equal to 10D50≤13μm。
The binder in the core powder of the artificial spherical ceramic composite sand is bentonite, and the addition amount of the bentonite is 3-5% of the weight of the core powder.
The binder in the outer powder of the artificial spherical ceramic composite sand is bentonite, and the sintering aid in the outer powder is MgO and CaO; the powder material of the outer layer comprises the following components in percentage by weight: 85-95% of one or more than two of flint clay, bauxite and corundum, 1-10% of bentonite, 1-5% of MgO and 1-5% of CaO.
The artificial spherical ceramic composite sand is preferably MgO 2% and CaO 2%.
The artificial spherical ceramic composite sand is granulated by adopting a rolling granulation method, placed in a rotary kiln for high-temperature sintering, and taken out of the kiln for natural cooling; the sintering process parameters are as follows: the sintering temperature is 1300-1500 ℃, and the sintering time is 1-5 h.
The rolling granulation method granulation of the artificial spherical ceramic composite sand comprises two steps: firstly, manufacturing an inner core structure; and secondly, coating outer layer powder on the surface.
The design idea of the invention is as follows:
the ceramic composite sand has an inner layer structure and an outer layer structure, wherein the inner core is made of nickel tailing slag, coal gangue or coal ash with relatively large grain diameter and other powder with general performance, the outer layer is made of high-grade flint clay, bauxite, corundum and other powder with relatively small grain diameter and excellent performance, and a proper amount of MgO and CaO are added into the bauxite to serve as sintering aids, so that the sintering temperature of the ceramic sand is reduced, the surface appearance of the ceramic sand is improved, and the economic efficiency is considered while the performance of the ceramic sand is ensured. The ceramic composite sand has the advantages of low density, good sphericity and surface smoothness, manually controllable components and particle size, strong customization, high strength and refractoriness.
Compared with the prior art, the invention has the following advantages and beneficial effects:
1. the ceramic composite sand of the invention is a 'core + outer layer' double-layer composite structure provided on the basis of the existing ceramic sand system, the core material adopts nickel tailing slag, coal gangue or fly ash with general performance, the shell material adopts high-grade flint clay, bauxite or corundum powder with excellent performance, compared with the existing single-structure ceramic sand, the performance of the outer layer material of the ceramic composite sand is obviously improved, and proper amount of MgO and CaO is added, the sintering temperature is reduced while the refractoriness of the ceramic sand is improved (the refractoriness can reach more than 1700 ℃), the ceramic sand has higher economy and better surface performance than the ceramic sand with the single structure, and can be widely used in the industry of molding materials for casting.
2. The bulk density of the composite ceramic sand is only 1.4-1.6 g/cm3The density is further reduced compared to single structure ceramic sand and compared to firing at over 1500 ℃ during the preparation of single structure ceramic sandThe sintering temperature of the composite ceramsite sand is only about 1350 ℃, so that the energy is saved, and the production cost is greatly reduced.
Drawings
Fig. 1 is a schematic structural diagram of the ceramic composite sand. Wherein, (a) is an outline drawing, and (b) is a cross-sectional drawing.
Detailed Description
The present invention will be described in further detail below with reference to examples.
Example 1:
in the embodiment, the inner core of the ceramic composite sand is fly ash, the shell is first-grade bauxite, and the bauxite comprises the following chemical components in percentage by weight: al (Al)2O3：82％，SiO2：10％，MgO：4％，CaO：1％，TiO2：2％，Fe2O3：1％。
The specific preparation process of the ceramic composite sand comprises the following steps:
(1) preparing materials: adding bentonite into the fly ash powder, wherein the bentonite accounts for 5% of the weight of the powder, putting the powder into a ball mill, performing dry grinding for 2 hours, fully mixing, and taking out the powder as a core raw material for preparing the ceramic composite sand;
(2) milling: adding bauxite powder, bentonite, MgO and CaO into a ball mill according to a weight ratio of 92:3:4:1, adding water, and mixing the materials in the ball mill according to the weight ratio: water: wet grinding the material at a ratio of 1.5:1:1 for 4h, taking out, drying and crushing the material into particles with the particle size of D50Bauxite powder with the particle size less than or equal to 13 mu m;
(3) and (3) granulation: adding a core raw material of the ceramic composite sand into a round pot type granulator, adjusting the rotating speed to 40r/min, adding atomized water into the material by using an atomization sprinkling can in the rotating process to form green pellets, adding bauxite powder with fine particle size when the particle size of more than 60 wt% of the green pellets reaches about 150 mu m, stopping the machine when the particle size of the green pellets reaches about 212 mu m, and taking out the green pellets to obtain the ceramic composite sand green pellets, wherein the total water addition amount is 15% of the total weight of the ceramic composite sand green pellets, and the granulation time is 1 h;
(4) screening and grading: sieving the granulated ceramic composite sand green balls by using a screen, crushing the part with the particle size of more than 380 mu m, and then granulating again, wherein the part with the particle size of less than 109 mu m is used as a primer to be directly used in the next granulation process;
(5) drying: and (3) placing the qualified ceramic composite sand green balls in a drying oven for drying until the weight is constant, wherein the drying temperature is 150 ℃, and the drying time is 1 h.
(6) And (3) sintering: sintering the dried ceramic composite sand green balls in a rotary kiln at 1500 ℃ for 1h, and then cooling to room temperature;
(7) scrubbing: placing the sintered ceramic composite sand in scrubbing equipment to scrub for 1h, and removing burrs and attached small solid particle powder on the surface of the ceramic composite sand;
(8) screening and grading: and screening the washed ceramic composite sand to obtain finished ceramic composite sand with different granularity specifications.
In the present example, the performance index of the artificial spherical casting sand-ceramic composite sand was measured as follows:
TABLE 1 Performance index of the products of the invention
| Name (R) | Angular coefficient of shape | Degree of refractoriness | Bulk density | Coefficient of thermal expansion | Loss on ignition |
| Ceramic composite sand | Is close to 1 | >1840℃ | 1.40～1.50g/cm3 | 4.5～5.0×10-6/K | <0.1wt％ |
Example 2:
in the embodiment, the inner core of the ceramic composite sand is coal gangue, the outer layer of the ceramic composite sand is bauxite such as second-grade bauxite, and the bauxite comprises the following chemical components in percentage by weight: al (Al)2O3：72％，SiO2：20％，MgO：2％，CaO：2％，TiO2：3％，Fe2O3：1％。
The specific preparation process of the ceramic composite sand comprises the following steps:
(1) preparing materials: adding bentonite into the coal gangue powder, wherein the bentonite accounts for 5% of the weight of the powder, putting the mixture into a ball mill, performing dry grinding for 2 hours, fully mixing, and taking out the mixture as a core raw material for preparing the ceramic composite sand;
(2) milling: adding bauxite powder, bentonite, MgO and CaO into a ball mill according to a weight ratio of 92:4:2:2, adding water, and mixing the materials in the ball mill according to a weight ratio of: water: wet grinding the material at a ratio of 1.5:1:1 for 4h, taking out, drying and crushing the material into particles with the particle size of D50Bauxite powder with the particle size less than or equal to 13 mu m;
(3) and (3) granulation: adding a core raw material of the ceramic composite sand into a round pot type granulator, adjusting the rotating speed to 35r/min, adding atomized water into the material by using an atomization sprinkling can in the rotating process to form green pellets, adding bauxite powder with fine particle size when the particle size of more than 60 wt% of the green pellets reaches about 150 mu m, stopping the machine when the particle size of the green pellets reaches about 212 mu m, and taking out the green pellets to obtain the ceramic composite sand green pellets, wherein the total water addition amount is 18% of the total weight of the ceramic composite sand green pellets, and the granulation time is 2 hours;
(4) screening and grading: sieving the granulated ceramic composite sand green balls by using a screen, crushing the part with the particle size of more than 380 mu m, and then granulating again, wherein the part with the particle size of less than 109 mu m is used as a primer to be directly used in the next granulation process;
(5) drying: and (3) placing the qualified ceramic composite sand green balls in a drying oven for drying until the weight is constant, wherein the drying temperature is 150 ℃, and the drying time is 1 h.
(6) And (3) sintering: sintering the dried ceramic composite sand green balls in a rotary kiln at 1350 ℃ for 3h, and then cooling to room temperature;
(7) scrubbing: placing the sintered ceramic composite sand in scrubbing equipment to scrub for 1h, and removing burrs and attached small solid particle powder on the surface of the ceramic composite sand;
(8) screening and grading: and screening the washed ceramic composite sand to obtain finished ceramic composite sand with different granularity specifications.
In the present example, the performance index of the artificial spherical casting sand-ceramic composite sand was measured as follows:
TABLE 2 Performance index of the product of the invention
| Name (R) | Angular coefficient of shape | Degree of refractoriness | Bulk density | Coefficient of thermal expansion | Loss on ignition |
| Ceramic composite sand | Is close to 1 | >1800℃ | 1.40～1.50g/cm3 | 4.5～5.0×10-6/K | <0.1wt％ |
Example 3:
in the embodiment, the core of the ceramic composite sand is nickel tailing slag, the outer layer of the ceramic composite sand is second-grade bauxite such as B, and the bauxite comprises the following chemical components in percentage by weight: al (Al)2O3：65％，SiO2：28％，MgO：1％，CaO：3％，TiO2：1％，Fe2O3：2％。
The specific preparation process of the ceramic composite sand comprises the following steps:
(1) preparing materials: adding bentonite which accounts for 5 percent of the weight of the powder into the nickel tailing slag powder, putting the powder into a ball mill, performing dry grinding for 2 hours, fully mixing, and taking out the powder as a core raw material for preparing ceramic composite sand;
(2) milling: adding bauxite powder, bentonite, MgO and CaO into a ball mill according to a weight ratio of 93:3:1:3, adding water, and mixing the materials in the ball mill according to a weight ratio of the ball: water: wet grinding the material at a ratio of 1.5:1:1 for 4h, taking out, drying and crushing the material into particles with the particle size of D50Bauxite powder with the particle size less than or equal to 13 mu m;
(3) and (3) granulation: adding a core raw material of the ceramic composite sand into a round pot type granulator, adjusting the rotating speed to 35r/min, adding atomized water into the material by using an atomization sprinkling can in the rotating process to form green pellets, adding bauxite powder with fine particle size when the particle size of more than 60 wt% of the green pellets reaches about 150 mu m, stopping the machine when the particle size of the green pellets reaches about 212 mu m, and taking out the green pellets to obtain the ceramic composite sand green pellets, wherein the total water addition amount is 16% of the total weight of the ceramic composite sand green pellets, and the granulation time is 2 hours;
(4) screening and grading: sieving the granulated ceramic sand green balls by using a screen, crushing the part with the particle size of more than 380 mu m, and granulating again, wherein the part with the particle size of less than 109 mu m is used as a primer to be directly used in the next granulation process;
(5) drying: and (3) placing the qualified ceramic composite sand green balls in a drying oven for drying until the weight is constant, wherein the drying temperature is 150 ℃, and the drying time is 1 h.
(6) And (3) sintering: sintering the dried ceramic composite sand green balls in a rotary kiln at 1300 ℃ for 2h, and then cooling to room temperature;
(7) scrubbing: placing the sintered ceramic composite sand in scrubbing equipment to scrub for 1h, and removing burrs and attached small solid particle powder on the surface of the ceramic composite sand;
(8) screening and grading: and screening the washed ceramic composite sand to obtain finished ceramic composite sand with different granularity specifications.
In the present example, the performance index of the artificial spherical casting sand-ceramic composite sand was measured as follows:
TABLE 3 Performance index of the products of the invention
| Name (R) | Angular coefficient of shape | Degree of refractoriness | Bulk density | Coefficient of thermal expansion | Loss on ignition |
| Ceramic composite sand | Is close to 1 | >1780℃ | 1.40～1.50g/cm3 | 4.5～5.0×10-6/K | <0.1wt％ |
Example 4:
in the embodiment, the core of the ceramic composite sand is fly ash and nickel tailing slag, the shell is bauxite such as second-grade bauxite, and the bauxite comprises the following chemical components in percentage by weight: al (Al)2O3：62％，SiO2：24％，MgO：3％，CaO：3％，TiO2：4％，Fe2O3：4％。
The specific preparation process of the ceramic composite sand comprises the following steps:
(1) preparing materials: adding bentonite into fly ash and nickel tailing slag powder in a weight ratio of 1:1, wherein the bentonite accounts for 5% of the weight of the powder, putting the powder into a ball mill, performing dry grinding for 2 hours, fully mixing, and taking out the powder to serve as a core raw material for preparing ceramic composite sand;
(2) milling: adding bauxite powder, bentonite, MgO and CaO into a ball mill according to a weight ratio of 86:8:3:3, adding water, and mixing the materials in a ball mill according to a weight ratio of ball: water: wet grinding the material at a ratio of 1.5:1:1 for 4h, taking out, drying and crushing the material into particles with the particle size of D50Bauxite powder with the particle size less than or equal to 13 mu m;
(3) and (3) granulation: adding a core raw material of the ceramic composite sand into a round pot type granulator, adjusting the rotating speed to 35r/min, adding atomized water into the material by using an atomization sprinkling can in the rotating process to form green pellets, adding bauxite powder with fine particle size when the particle size of more than 60 wt% of the green pellets reaches about 150 mu m, stopping the machine when the particle size of the green pellets reaches about 212 mu m, and taking out the green pellets to obtain the ceramic composite sand green pellets, wherein the total water addition amount is 15% of the total weight of the ceramic composite sand green pellets, and the granulation time is 2 hours;
(4) screening and grading: sieving the granulated ceramic composite sand green balls by using a screen, crushing the part with the particle size of more than 380 mu m, and then granulating again, wherein the part with the particle size of less than 109 mu m is used as a primer to be directly used in the next granulation process;
(5) drying: and (3) placing the qualified ceramic composite sand green balls in a drying oven for drying until the weight is constant, wherein the drying temperature is 150 ℃, and the drying time is 1 h.
(6) And (3) sintering: sintering the dried ceramic composite sand green ball in a rotary kiln at 1280 ℃ for 4h, and then cooling to room temperature;
(7) scrubbing: placing the sintered ceramic composite sand in scrubbing equipment to scrub for 1h, and removing burrs and attached small solid particle powder on the surface of the ceramic composite sand;
(8) screening and grading: and screening the washed ceramic composite sand to obtain finished ceramic composite sand with different granularity specifications.
In the present example, the performance index of the artificial spherical casting sand-ceramic composite sand was measured as follows:
TABLE 4 Performance index of the products of the invention
| Name (R) | Angular coefficient of shape | Degree of refractoriness | Bulk density | Coefficient of thermal expansion | Loss on ignition |
| Ceramic composite sand | Is close to 1 | >1750℃ | 1.40～1.50g/cm3 | 4.5～5.0×10-6/K | <0.1wt％ |
Example 5:
in the embodiment, the inner core of the ceramic composite sand is fly ash, coal gangue and nickel tailing slag, the shell is three-level bauxite, and the bauxite comprises the following chemical components in percentage by weight: al (Al)2O3：60％，SiO2：30％，MgO：3％，CaO：3％，TiO2：2％，Fe2O3：2％。
The specific preparation process of the ceramic composite sand comprises the following steps:
(1) preparing materials: adding bentonite into fly ash, coal gangue and nickel tailing slag powder in a weight ratio of 1:1:1, wherein the bentonite accounts for 5% of the weight of the powder, putting the powder into a ball mill, performing dry grinding for 2 hours, fully mixing, and taking out the powder to serve as a core raw material for preparing ceramic composite sand;
(2) milling: adding bauxite powder, bentonite, MgO and CaO into a ball mill according to the weight ratio of 90:4:3:3, adding water, and mixing the materials in the ball mill according to the weight ratio: water: wet grinding the material at a ratio of 1.5:1:1 for 4h, taking out, drying and crushing the material into particles with the particle size of D50Bauxite powder with the particle size less than or equal to 13 mu m;
(3) and (3) granulation: adding a core raw material of the ceramic composite sand into a round pot type granulator, adjusting the rotating speed to 30r/min, adding atomized water into the material by using an atomization sprinkling can in the rotating process to form green pellets, adding bauxite powder with fine particle size when the particle size of more than 60 wt% of the green pellets reaches about 150 mu m, stopping the machine when the particle size of the green pellets reaches about 212 mu m, and taking out the green pellets to obtain the ceramic composite sand green pellets, wherein the total water addition amount is 20% of the total weight of the ceramic composite sand green pellets, and the granulation time is 3 hours;
(4) screening and grading: sieving the granulated ceramic composite sand green balls by using a screen, crushing the part with the particle size of more than 380 mu m, and then granulating again, wherein the part with the particle size of less than 109 mu m is used as a primer to be directly used in the next granulation process;
(5) drying: and (3) placing the qualified ceramic composite sand green balls in a drying oven for drying until the weight is constant, wherein the drying temperature is 150 ℃, and the drying time is 1 h.
(6) And (3) sintering: sintering the dried ceramic composite sand green balls in a rotary kiln at 1250 ℃ for 5h, and then cooling to room temperature;
(7) scrubbing: placing the sintered ceramic composite sand in scrubbing equipment to scrub for 1h, and removing burrs and attached small solid particle powder on the surface of the ceramic composite sand;
(8) screening and grading: and screening the washed ceramic composite sand to obtain finished ceramic composite sand with different granularity specifications.
In the present example, the performance index of the artificial spherical casting sand-ceramic composite sand was measured as follows:
TABLE 4 Performance index of the products of the invention
| Name (R) | Angular coefficient of shape | Degree of refractoriness | Bulk density | Coefficient of thermal expansion | Loss on ignition |
| Ceramic composite sand | Is close to 1 | >1700℃ | 1.40～1.50g/cm3 | 4.5～5.0×10-6/K | <0.1wt％ |
As shown in figure 1, the structure of the ceramic composite sand is mainly divided into an inner layer and an outer layer, the inner core is made of nickel tailing slag, coal gangue or fly ash with relatively large grain diameter and other powder with general performance, the outer layer is made of high-grade flint clay, bauxite or corundum and other powder with relatively small grain diameter and excellent performance, and the grain diameter of the inner core powder is required to be D50Not more than 25 mu m, the grain diameter of the bauxite powder on the outer layer is required to be D50Less than or equal to 13 mu m. The obtained ceramic composite sand has good surface quality, excellent performance, high refractoriness and low breakage rate, and can be used for producing non-ferrous alloy castings, iron castings and steel castings.
The above description is only an embodiment of the present invention, and is not intended to limit the present invention, and all technical solutions obtained by equivalent replacement or equivalent transformation fall within the protection scope of the present invention.
Claims (5)
1. The artificial spherical ceramic composite sand is characterized in that the structure of the ceramic composite sand is mainly divided into an inner layer and an outer layer, and the inner core adopts main powder with a coarse grain diameter as follows: one or more than two of nickel tailing slag, coal gangue and fly ash, wherein the outer layer adopts main powder with smaller grain size as follows: one or more of flint clay, bauxite and corundum; wherein the particle size of the core powder is not less than 13D50Less than or equal to 25 mu m, and the grain diameter of the powder material at the outer layer is less than or equal to 10D50≤13μm；
The binder in the outer layer powder is bentonite, and the sintering aid in the outer layer powder is MgO and CaO; the powder material of the outer layer comprises the following components in percentage by weight: 85-95% of one or more than two of flint clay, bauxite and corundum, 1-10% of bentonite, 1-5% of MgO and 1-5% of CaO.
2. The artificial spherical ceramic composite sand according to claim 1, wherein the binder in the core powder is bentonite, and the amount of bentonite added is 3 to 5% by weight of the core powder.
3. Artificial spherical ceramic composite sand according to claim 1, characterised in that preferably, MgO 2% and CaO 2%.
4. The artificial spherical ceramic composite sand according to claim 1, wherein the ceramic composite sand is granulated by a rolling granulation method, sintered at a high temperature in a rotary kiln, taken out of the kiln and naturally cooled; the sintering process parameters are as follows: the sintering temperature is 1300-1500 ℃, and the sintering time is 1-5 h.
5. Artificial spherical ceramic composite sand according to claim 4, wherein the granulation by the tumbling granulation method is divided into two steps: firstly, manufacturing an inner core structure; and secondly, coating outer layer powder on the surface.
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| CN107298584A (en) * | 2017-05-25 | 2017-10-27 | 宁夏共享模具有限公司 | A kind of casting ceramsite sand and preparation method thereof |
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