A method and device for determining the content of free flaky mica in sand samples

Abstract

The present invention discloses a method and a device for determining the content of free flaky mica in a sand sample, comprising the following steps: obtaining two sand samples of different particle size ranges of a certain mass through drying, cooling, screening and grading; manually selecting mica for the sand sample of a larger particle size range under a magnifying glass, and measuring the mass of the manually selected mica; putting the sand sample of a smaller particle size range into an air separator, obtaining free flaky mica and a primary air-selected sand sample through air separation, and then repeatedly performing air separation operations on the primary air-selected sand sample until no free flaky mica is separated, and measuring the mass of the air-selected mica; and calculating the content of free flaky mica in the sand sample using the mass of the manually selected mica, the mass of the air-selected mica and the mass of the sand sample. The method and device for determining the content of free flaky mica in a sand sample disclosed by the present invention can reduce the difficulty of manually selecting free mica, and the detection method is more efficient; so that the accuracy of the free flaky mica content finally obtained is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of building material detection, and particularly relates to a method for determining the content of free flaky mica in a sand sample and a device thereof. Background Art

[0002] With the ever-increasing scale of construction projects and the strengthening of national efforts to protect natural resources, the availability of natural fine aggregate in concrete is decreasing. In particular, in water conservancy and hydropower projects, where limited material sources are available, fine aggregate is often obtained by crushing the parent rock to produce manufactured sand. Mica is often found in the parent rock of sandstone, such as marble and granite. After crushing, it is peeled from the rock mass and exposed. Mica particles are flaky, with a smooth, jointed surface. Their low adhesion to cement binders contributes to the generation of cracks and defects in concrete and is a harmful substance in concrete fine aggregate.

[0003] Current domestic standards and specifications clearly stipulate limits for free mica content in sand. For example, the "Specifications for Construction of Hydraulic Concrete" (DL / T 5144-2015), the "Specifications for Construction of Hydraulic Concrete" (SL 677-2014), and the "Regulations for the Investigation of Natural Building Materials for Hydropower and Water Conservancy Projects" (DL / T 5388-2007) all require a mica content of less than 2%. The "Specifications for Construction of Concrete for Water Transport Engineering" (JTJ 202-2011) and the "Standard for Quality and Inspection Methods of Sand and Stone for Ordinary Concrete" (JGJ 52-2006) require a mica content of less than 1.0% (for projects with frost resistance requirements) and ≤ 2% (for other projects). The "Construction Sand" (GB / T 14684-2011) requires a mica content of ≤ 1% (Class I sand) and ≤ 2% (Class II and III sand). Current specifications and standards all utilize a quantitative test method involving manual selection of samples under a 3x to 5x magnification. This method is time-consuming and laborious, and can cause some eye damage to the tester. Furthermore, test results often suffer from significant human error due to varying mica selection criteria and operational procedures. The misuse of manufactured sand with a high mica content as the primary fine aggregate in concrete projects can lead to significant quality issues. Testing for mica content in fine aggregate is essential for project quality control. Therefore, developing new, accurate, and efficient methods for measuring mica content is essential for adapting to the current era of construction and quality control. Summary of the Invention

[0004] The purpose of the present invention is to overcome the deficiencies in the prior art and to provide a method and a device for determining the content of free flaky mica in a sand sample.

[0005] To achieve the above object, the present invention is implemented by adopting the following technical solutions:

[0006] In one aspect, the present invention provides a method for determining the content of free flaky mica in a sand sample, comprising the following steps:

[0007] After drying, cooling, screening and grading, two sand samples of a certain mass and different particle size ranges are obtained;

[0008] For sand samples with a larger particle size range, mica was manually selected under a magnifying glass, and the quality of the manually selected mica was measured;

[0009] The sand sample with a smaller particle size range is put into the air separator, and the free flake mica and the primary air-selected sand sample are obtained through air separation. The primary air-selected sand sample is then repeatedly subjected to air separation and separation operations until no free flake mica is separated. The quality of the air-selected mica is then measured.

[0010] The content of free flake mica in the sand sample was calculated using the mass of manually selected mica, the mass of wind-selected mica and the mass of the sand sample.

[0011] Furthermore, the method for obtaining two sand samples with different particle size ranges by grading is as follows:

[0012] Weigh the shrunken sand sample and dry it in an oven at 105±5℃ to constant weight, cool it to room temperature, place the sand sample on a sieve with the sieve holes arranged from top to bottom and from large to small, and sieve out particles >5mm and <0.315mm to obtain 2-5mm sand samples and 0.315-2mm sand samples, where the basic sizes of the sieve holes are 5, 2, and 0.315mm.

[0013] Furthermore, the air separator is equipped with a funnel-shaped feed barrel, a hollow chamber is connected to the bottom of the feed barrel, a blower with an air outlet facing the lower port of the feed barrel is arranged inside the hollow chamber and located obliquely below the lower port of the feed barrel, the hollow chamber is provided with a funnel-shaped sand discharge port extending downward in the same vertical direction as the feed barrel, and a semi-funnel-shaped mica discharge port connected to the hollow chamber is arranged on the side of the sand discharge port away from the blower, and the height of the dividing part between the sand discharge port and the mica discharge port is not higher than the blower.

[0014] Furthermore, the air separator further includes a multi-channel screening assembly, which is located obliquely below the lower end of the feed barrel, away from the blower and above the sand discharge port and the mica discharge port; the multi-channel screening assembly divides the hollow chamber into a first mica cavity, an intermediate mixing cavity and a first sand cavity in sequence from the side away from the blower toward the sand discharge port;

[0015] The cavity inlet end faces of the first mica cavity, the intermediate mixing cavity and the first sand cavity are staggered step-shaped oblique surfaces, the first mica cavity extends downward into the mica discharge port in an arc shape, the first sand cavity extends downward into the sand discharge port, the intermediate mixing cavity extends downward in an arc shape and bifurcates in the middle to form a second sand cavity extending to the sand discharge port and a second mica cavity extending to the mica discharge port, the second sand cavity and the second mica cavity are separated and connected at the cavity bifurcation by a separation screen that only allows sand to pass and is detachable and replaceable with different apertures, and the inlet end of the second sand cavity is connected and arranged below the separation screen;

[0016] An arc-shaped baffle is further provided in the intermediate mixing cavity. The arc-shaped baffle is provided on the inner wall above the separation screen, extends downward, and the concave surface of the arc-shaped baffle faces the inlet end face of the intermediate mixing cavity.

[0017] Furthermore, the sand sample is put into the air separator for air separation and separation operation method is as follows:

[0018] The blower angle is adjusted to 0-45°, the wind speed is controlled to 4.2-4.9 m / s, and the temperature is controlled to 15-25°C. The sand samples are put into the feed barrel of the air separator in sequence, so that the free flake mica slows down the sedimentation speed under the action of wind and deviates from the vertical falling direction to be discharged into the mica discharge port. At the same time, the sand particles are discharged from the sand particle discharge port in a vertical direction to obtain free flake mica and the primary air-selected sand sample; the primary air-selected sand sample is repeatedly subjected to the air separation operation until the amount of free flake mica no longer changes.

[0019] Furthermore, it also includes: putting the sand samples with larger particle size range that have been manually selected into an air separator for air separation.

[0020] Furthermore, the mica content calculation formula is expressed as:

[0021] ;

[0022] Where: is the mica content of sand sample, %; To manually select the quality of mica, is the mass of wind-selected mica, G is the mass of sand sample, g.

[0023] On the other hand, the present invention also provides a device for determining the content of free flaky mica in sand samples, which is equipped with a funnel-shaped feed barrel, a hollow chamber is connected to the bottom of the feed barrel, and a blower with an air outlet facing the lower port of the feed barrel is arranged inside the hollow chamber and obliquely below the lower port of the feed barrel. The hollow chamber is provided with a funnel-shaped sand grain discharge port extending downward in the same vertical direction as the feed barrel, and a semi-funnel-shaped mica discharge port connected to the hollow chamber is arranged on the side of the sand grain discharge port away from the blower, and the height of the dividing part between the sand grain discharge port and the mica discharge port is not higher than the blower.

[0024] Furthermore, it also includes a multi-channel screening assembly, which is located obliquely below the lower end of the feed barrel, away from the blower and above the sand discharge port and the mica discharge port; the multi-channel screening assembly divides the hollow chamber into a first mica cavity, an intermediate mixing cavity and a first sand cavity in sequence from the side away from the blower toward the sand discharge port;

[0025] The inlet end faces of the first mica cavity, the intermediate mixing cavity and the first sand cavity are staggered stepped bevel surfaces, the first mica cavity extends downward into the mica discharge port in an arc shape, the first sand cavity extends downward into the sand discharge port, the intermediate mixing cavity extends downward in an arc shape and forks in the middle to form a second sand cavity extending to the sand discharge port and a second mica cavity extending to the mica discharge port, the second sand cavity and the second mica cavity are separated and connected at the cavity bifurcation by a separation screen that only allows sand to pass through and is detachable and replaceable with different apertures, and the inlet end of the second sand cavity is connected and arranged below the separation screen.

[0026] Furthermore, an arc-shaped baffle is provided in the intermediate mixing cavity. The arc-shaped baffle is provided on the inner wall above the separation screen, extends downward, and the concave surface of the arc-shaped baffle faces the inlet end face of the intermediate mixing cavity.

[0027] Furthermore, the pore size of the separation screen is in the range of 0.4 to 0.6 mm.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] The present invention provides a method and a device for determining the content of free flaky mica in a sand sample. The method adopts a combination of manual selection and air separation, and adds a 2mm sieve grading on the basis of standard screening, thereby greatly reducing the difficulty of manual selection of free mica. The addition of air separation equipment on the basis of manual selection improves the mechanization degree of the test and makes the detection method more efficient. The method also improves the accuracy of the free flaky mica content finally obtained. The method has the advantages of a high degree of mechanization in operation and good actual measurement effect, and is suitable for experimental research on determining the content of free flaky mica in sand samples. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 A flow chart of a method for determining the content of free flake mica in a sand sample provided by an embodiment of the present invention;

[0031] Figure 2 A schematic diagram of a device for determining the content of free flake mica in a sand sample provided by an embodiment of the present invention;

[0032] Figure 3 A cross-sectional view of a device for determining the content of free flake mica in a sand sample provided by an embodiment of the present invention;

[0033] Figure 4 A schematic diagram of a multi-channel screening assembly provided in an embodiment of the present invention.

[0034] In the picture:

[0035] 1. Feed barrel; 2. Hollow chamber; 3. Blower; 4. Sand discharge port; 5. Mica discharge port; 6. First mica cavity; 7. First sand cavity; 8. Intermediate mixing cavity; 9. Second mica cavity; 10. Second sand cavity; 11. Separation screen; 12. Arc baffle; 13. Support frame; 14. Arc plate. DETAILED DESCRIPTION

[0036] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention.

[0037] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0038] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances. Example

[0039] like Figure 1 As shown, an embodiment of the present invention provides a method for determining the content of free flaky mica in a sand sample, comprising the following steps:

[0040] Step S1: obtaining two sand samples of a certain mass and different particle size ranges through drying, cooling, screening and classification;

[0041] Step S2: manually selecting mica from the sand sample with a larger particle size range under a magnifying glass, and measuring the mass of the manually selected mica;

[0042] Step S3: The manually selected sand samples in the larger particle size range and the sand samples in the smaller particle size range are respectively fed into an air separator to obtain free flake mica and primary air-selected sand samples through air separation;

[0043] Step S4: Repeated air separation and separation operations are performed on the initial air-selected sand sample until no free flake mica is separated, and the quality of the air-selected mica is measured;

[0044] Step S5: The free flaky mica content in the sand sample is calculated using the mass of manually selected mica, the mass of air-selected mica, and the mass of the sand sample.

[0045] In this embodiment, the method for obtaining two sand samples with different particle size ranges is as follows:

[0046] Weigh the shrunken sand sample and dry it in an oven at 105±5℃ to constant weight, cool it to room temperature, place the sand sample on a sieve with the sieve holes arranged from top to bottom and from large to small, and sieve out particles >5mm and <0.315mm to obtain 2-5mm sand samples and 0.315-2mm sand samples, where the basic sizes of the sieve holes are 5, 2, and 0.315mm.

[0047] In this embodiment, if Figure 2 As shown, the air separator is equipped with a funnel-shaped feeding barrel 1, a hollow chamber 2 is connected to the bottom of the feeding barrel 1, and a blower 3 with an air outlet facing the lower port of the feeding barrel 1 is arranged inside the hollow chamber 2 and located obliquely below the lower port of the feeding barrel 1. The hollow chamber 2 extends downward in the same vertical direction as the feeding barrel 1 and is equipped with a funnel-shaped sand discharge port, and a semi-funnel-shaped mica discharge port 5 connected to the hollow chamber 2 is arranged on the side of the sand discharge port away from the blower 3, and the height of the dividing part between the sand discharge port and the mica discharge port 5 is not higher than the blower 3.

[0048] The air separator also includes a multi-channel screening assembly, which is located obliquely below the lower end of the feed barrel 1, away from the blower 3 and above the sand discharge port and the mica discharge port 5; the multi-channel screening assembly divides the hollow chamber 2 from the side away from the blower 3 to the sand discharge port in sequence into a first mica cavity 6, an intermediate mixing cavity 8 and a first sand cavity 7.

[0049] The inlet end faces of the first mica cavity 6, the intermediate mixing cavity 8, and the first sand cavity 7 are staggered stepped beveled surfaces, or the inlet end faces of the above cavities are in the same plane and are beveled surfaces as a whole, with the beveled surfaces facing the discharge port of the feed barrel. The first mica cavity 6 extends downward into the mica discharge port 5 in an arc shape, the first sand cavity 7 extends downward into the sand discharge port 4, the intermediate mixing cavity 8 extends downward in an arc shape and bifurcates in the middle to form a second sand cavity 10 extending toward the sand discharge port and a second mica cavity 9 extending toward the mica discharge port 5. The second sand cavity 10 and the second mica cavity 9 are separated and connected at the cavity bifurcation by a separation screen 11 that only allows sand to pass through and is removable and replaceable with different apertures. The inlet end of the second sand cavity 10 is connected and arranged below the separation screen 11.

[0050] Specifically, the slope of the separation screen 11 should be set to be gentler so that the sand particles can roll over the separation screen 11 and fall through the meshes to separate, rather than falling directly into the mica discharge port when the slope is too steep. Here, the slope range can be 5% to 45%.

[0051] An arc-shaped baffle 12 is further provided in the middle mixing cavity. The arc-shaped baffle 12 is provided on the inner wall above the separation screen, extends downward, and the concave surface of the arc-shaped baffle faces the inlet end face of the middle mixing cavity.

[0052] Specifically, in this embodiment, the multi-channel screening assembly uses an arc-shaped plate 14, such as stainless steel, plastic, etc. Figure 2 、 Figure 3 、 Figure 4 As shown, the hollow chamber 2 is divided into channels by a plurality of curved plates 14 to form the above-mentioned first mica channel 6, intermediate mixing channel 8, first sand channel 7, second mica channel 9, and second sand channel 10. In order to facilitate the rapid and smooth transportation of sand and mica through the channels by blowing air, the curved concave surfaces of the first mica channel 6, intermediate mixing channel 8, first sand channel 7, second mica channel 9, and second sand channel 10 are all oriented toward the blower 3.

[0053] It should be noted that, in the embodiment of the present invention, the multi-channel screening assembly can also adopt a structure such as an arc-shaped cylindrical pipe, which can be arranged in the hollow chamber 2. With slight adaptive adjustments, it can also play the above-mentioned functions and effects. In addition, in order to facilitate the display of the internal cavity structure of the hollow chamber 2, Figure 3 A simplified structural cross-sectional diagram is used and some side walls of the hollow chamber 2 and the fixed connection details of the multi-channel screening assembly are omitted. However, the omission and simplification in the above diagram does not affect the understanding and implementation of the technical solution of the present invention by those skilled in the art.

[0054] In this embodiment, the different settling velocities of mica and sand determine the wind speed control range. It can be seen that within the particle size range of 0.315 to 2 mm, a wind speed of approximately 2.5 to 3.5 m / s can separate the two. Furthermore, based on the upward angle of blower 3, which is 0 to 45°, the wind speed is calculated to be controlled at approximately 4.2 to 4.9 m / s. Furthermore, if manually selected sand samples with larger particle sizes (2 to 5 mm) are fed into the air separator for separation, the wind speed needs to be increased from 4.2 to 4.9 m / s to separate the larger flake mica particles.

[0055] Then, the operation method of feeding the sand sample into the air separator for air separation is as follows: adjust the angle of the blower 3 to be controlled at 0-45°, the wind speed to be controlled at 4.2-4.9 m / s, and the temperature to be controlled at 15-25°C, and feed the sand sample into the feed barrel 1 of the air separator in sequence, so that the free flake mica slows down the sedimentation speed under the action of wind and deviates from the vertical falling direction to be discharged into the mica discharge port 5, while the sand particles maintain the vertical direction and are discharged from the sand particle discharge port 1 to obtain free flake mica and the first air-separated sand sample; then the first air-separated sand sample is repeatedly subjected to the air separation operation until the amount of free flake mica no longer changes.

[0056] In this embodiment, the mica content calculation formula is expressed as:

[0057] ;

[0058] Where: is the mica content of sand sample, %; To manually select the quality of mica, is the mass of wind-selected mica, G is the mass of sand sample, g.

[0059] An embodiment of the present invention also provides a device for determining the content of free flaky mica in a sand sample, which is equipped with a funnel-shaped feeding barrel 1, a hollow chamber 2 connected to the bottom of the feeding barrel 1, a blower 3 with an air outlet facing the lower port of the feeding barrel 1 is arranged inside the hollow chamber 2 and located obliquely below the lower port of the feeding barrel 1, the hollow chamber 2 is downwardly extended in the same vertical direction as the feeding barrel 1 and is equipped with a funnel-shaped sand grain discharge port, and a semi-funnel-shaped mica discharge port 5 connected to the hollow chamber 2 is arranged on the side of the sand grain discharge port away from the blower 3, and the height of the dividing part between the sand grain discharge port and the mica discharge port 5 is not higher than the blower 3.

[0060] In this embodiment, a multi-channel screening assembly is further included, which is located obliquely below the lower end of the feed barrel 1, away from the blower 3 and above the sand discharge port and the mica discharge port 5. The multi-channel screening assembly divides the hollow chamber 2 into a first mica cavity 6, an intermediate mixing cavity 8, and a first sand cavity 7 in sequence from the side away from the blower 3 toward the sand discharge port.

[0061] The inlet end faces of the first mica cavity 6, the intermediate mixing cavity 8 and the first sand cavity 7 are staggered step-like oblique surfaces. The first mica cavity 6 extends downward into the mica discharge port 5 in an arc shape, and the first sand cavity 7 extends downward into the sand discharge port 4. The intermediate mixing cavity 8 extends downward in an arc shape and forks in the middle to form a second sand cavity 10 extending to the sand discharge port and a second mica cavity 9 extending to the mica discharge port 5. The second sand cavity 10 and the second mica cavity 9 are separated and connected at the cavity bifurcation by a separation screen that only allows sand to pass through and can be removed and replaced with different apertures, and the inlet end of the second sand cavity 10 is connected and arranged below the separation screen 11.

[0062] The aperture size of the detachable separation screen 11 ranges from 0.4 to 0.6 mm. Specifically, the aperture can be 0.4, 0.45, 0.5, 0.55, or 0.60 mm.

[0063] The above are only preferred embodiments of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for determining the content of free flaky mica in a sand sample, characterized in that: The steps include: After drying, cooling, screening and grading, two sand samples of a certain mass and different particle size ranges are obtained; For sand samples with a larger particle size range, mica was manually selected under a magnifying glass, and the mass of the manually selected mica was measured; The sand samples with larger particle size range and the sand samples with smaller particle size range after manual selection are respectively put into the air separator, and the free flake mica and the primary air-selected sand samples are obtained through air separation, and then the primary air-selected sand samples are repeatedly air-selected and separated until the free flake mica is no longer separated, and the quality of the air-selected mica is measured; The content of free flake mica in the sand sample was calculated using the mass of manually selected mica, the mass of wind-selected mica and the mass of the sand sample. The method for obtaining two sand samples with different particle size ranges is as follows: Weigh the shrunken sand sample and dry it in an oven at 105±5℃ to constant weight, cool it to room temperature, and place the sand sample on a sieve arranged from top to bottom and from large to small according to the sieve holes, and sieve out particles >5mm and <0.315mm to obtain 2-5mm sand samples and 0.315-2mm sand samples, wherein the basic sizes of the sieve holes are 5, 2, and 0.315mm; The sand sample is put into the air separator for air separation and the operation method is as follows: The sand samples are sequentially put into the feeding barrel of the air separator, so that the free flaky mica slows down the settling speed under the action of wind and deviates from the vertical falling direction to be discharged into the mica discharge port, while the sand particles are discharged from the sand particle discharge port in a vertical direction, thereby obtaining the free flaky mica and the primary air separation sand sample; The first air-selected sand sample is then repeatedly subjected to air-selection operation until the amount of free flake mica no longer changes; The air separator is provided with a funnel-shaped feed barrel, a hollow chamber is connected below the feed barrel, a blower with an air outlet facing the lower port of the feed barrel is provided inside the hollow chamber and at a position obliquely below the lower port of the feed barrel, the hollow chamber is provided with a funnel-shaped sand discharge port extending downward in the same vertical direction as the feed barrel, and a semi-funnel-shaped mica discharge port connected to the hollow chamber is provided on the side of the sand discharge port away from the blower, and the height of the dividing portion between the sand discharge port and the mica discharge port is not higher than the blower; The air separator also includes a multi-channel screening assembly, which is located obliquely below the lower end of the feed barrel, away from the blower and above the sand discharge port and the mica discharge port; the multi-channel screening assembly divides the hollow chamber from the side away from the blower to the sand discharge port in sequence into a first mica cavity, an intermediate mixing cavity and a first sand cavity; The cavity inlet end faces of the first mica cavity, the intermediate mixing cavity and the first sand cavity are staggered step-shaped oblique surfaces, the first mica cavity extends downward into the mica discharge port in an arc shape, the first sand cavity extends downward into the sand discharge port, the intermediate mixing cavity extends downward in an arc shape and bifurcates in the middle to form a second sand cavity extending to the sand discharge port and a second mica cavity extending to the mica discharge port, the second sand cavity and the second mica cavity are separated and connected at the cavity bifurcation by a separation screen that only allows sand to pass and can be detached and replaced with different apertures, and the inlet end of the second sand cavity is connected and arranged below the separation screen; An arc-shaped baffle is also arranged in the middle mixing cavity. The arc-shaped baffle is arranged on the inner wall above the separation screen and extends downward, and the concave surface of the arc-shaped baffle faces the inlet end surface of the middle mixing cavity.

2. The method for determining the content of free flaky mica in a sand sample according to claim 1, characterized in that: The blower angle is adjusted to be controlled within the range of 0 to 45 degrees, the wind speed is controlled within the range of 4.2 to 4.9 m / s, and the temperature is controlled within the range of 15 to 25 degrees Celsius, wherein the wind speed increases as the blower angle increases.

3. The method for determining the content of free flaky mica in a sand sample according to claim 1, characterized in that: The calculation formula of mica content is expressed as: ； Where: Q m is the mica content of sand sample, %; m 1 To manually select the quality of mica, m 2 To determine the quality of wind-selected mica, G is the mass of sand sample, g.

4. The method for determining the content of free flaky mica in a sand sample according to claim 1, characterized in that: The aperture size of the separation screen is in the range of 0.4 to 0.6 mm.

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