Eccentric stirring device for purifying metal silicon

Abstract

In order to solve the problem of poor effect of purifying metal silicon by adopting a wet method, the invention firstly provides the eccentric stirring device for purifying the metal silicon. Comprising a base, a power device and a stirring tank, an angle is formed between the power device and the supporting plate, and the stirring tank and the power device are eccentrically arranged. The stirring tank and the power device are eccentrically arranged, and silicon powder which is easily pressed at the bottom of the stirring tank originally can continuously flow out and emerge on the surface by utilizing the gravity of powder and centrifugal force generated during rotation of the stirring tank. The flowability of the powder in the stirring tank is improved, so that the purification efficiency is improved.

Description

Technical Field

[0001] The invention relates to the technical field of metal silicon preparation, and in particular to an eccentric stirring device for purifying metal silicon. Background Art

[0002] Metallic silicon is a product smelted from quartz and coke in an electric furnace. Its main component is silicon, which usually accounts for more than 99.99%, while the remaining impurities mainly include iron, aluminum, calcium and other elements. Metallic silicon is widely used in many fields, such as semiconductors, metallurgical industry, foundry industry and solar thermal power generation.

[0003] With the rapid development of high-end application fields such as semiconductors and solar energy, the purity requirements for metallic silicon are also increasing. High-purity metallic silicon has become an indispensable key material in these fields. Therefore, purifying metallic silicon to meet the needs of high-end application fields has become an inevitable choice.

[0004] In the process of metallurgical preparation of solar-grade silicon, wet acid leaching technology plays a pivotal role. The various metallurgical process routes for preparing solar-grade polysilicon currently proposed all include the key step of wet acid leaching. Wet acid leaching can not only directly process metallurgical-grade silicon and effectively remove impurities concentrated at silicon grain boundaries, but also further purify metallurgical-grade silicon after slag refining.

[0005] During the purification process, mechanical stirring or magnetic stirring is often used. Mechanical stirring is to directly act on the liquid or solid-liquid mixture through a mechanical stirring device (such as a stirring rod, propeller, etc.), and promote the mixing and homogenization of the materials through the shear force and eddy current effect generated by the rotation. Due to the small particle size and high density of metal silicon powder, it is difficult for mechanical stirring to fully stir the metal silicon powder deposited at the bottom, resulting in incomplete contact with the solution, so the wet treatment effect is greatly reduced. The magnetic stirrer uses magnets and rotating magnetic fields to achieve stirring. There is a rotating magnetic field inside the stirrer. When the stirrer (containing a magnet inside) is placed in the liquid to be stirred, the rotating magnetic field will drive the stirrer to rotate, thereby stirring the liquid. Compared with mechanical stirring, the magnetic stirrer can avoid the contamination of the metal silicon powder by the stirring components to a certain extent, and can produce a relatively uniform stirring effect, but for particularly viscous or high-density metal silicon slurry, its cost is relatively high when it is necessary to achieve a uniform stirring effect.

[0006] Therefore, how to improve the stirring uniformity under cost-controllable conditions and thereby improve the efficiency of metallic silicon in wet processing is an urgent problem to be solved by those skilled in the art. Summary of the invention

[0007] In order to solve the problem of poor effect in the existing wet method for purifying metallic silicon, the present invention first provides an eccentric stirring device for purifying metallic silicon. The specific technical scheme is as follows:

[0008] The eccentric stirring device for purifying metallic silicon comprises a base, a support plate is arranged on the base, a power device and a stirring tank; the power device is arranged at an angle to the support plate, and the stirring tank is eccentrically arranged to the power device.

[0009] Furthermore, the eccentricity between the stirring tank and the power device is less than 5 cm.

[0010] Furthermore, a frame is coaxially arranged outside the stirring tank.

[0011] Furthermore, a connecting plate is provided between the stirring tank and the power device.

[0012] Furthermore, an adjustment portion is provided between the power device and the support plate.

[0013] Furthermore, the power device is fixedly connected to the support plate.

[0014] The present invention proposes an innovative solution to the problem of uneven stirring of powder in a stirring tank during the wet treatment of metallic silicon. By eccentrically arranging the stirring tank and the power device, the weight of the powder and the centrifugal force generated by the rotation of the stirring tank are utilized, so that the silicon powder that was originally easily pressed at the bottom of the stirring tank can continuously flow out and float to the surface. This eccentric design causes the solution to be in an irregular flow state in the stirring tank, thereby effectively impacting the high places and compacting the bottom powder, significantly increasing the fluidity of the powder in the stirring tank. Due to the enhanced fluidity of the powder, its contact area and probability with the treatment solution are greatly improved. This means that the effect of the wet treatment will be significantly improved, because more silicon powder can fully react with the solution, thereby improving the purification efficiency. Secondly, the irregular flow generated by the eccentrically arranged power device helps to break the close combination between the powders, reduce the dead corners of stirring, and further improve the uniformity of stirring. Finally, this design also helps to reduce the energy consumption required for magnetic stirring, because the natural effects of gravity and centrifugal force assist the stirring process to a certain extent. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the eccentric stirring device for purifying metallic silicon of the present invention.

[0016] Reference numerals:

[0017] 1 tank cover, 2 mixing tank, 3 frame, 4 connecting plate, 5 power device, 6 adjustment part, 7 groove, 8 support plate, 9 base. DETAILED DESCRIPTION

[0018] In the description of the present invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc., indicating orientations or positional relationships, are 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 should not be understood as a limitation on the present invention.

[0019] In the description of the present invention, unless otherwise specified and limited, it should be noted that the terms "installed", "connected" and "connected" should be understood in a broad sense. For example, it can be a mechanical connection or an electrical connection, or it can be the internal connection of two components. It can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to the specific circumstances.

[0020] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "examples", "specific examples" or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0021] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0022] like Figure 1 As shown, the eccentric stirring device for purifying metallic silicon includes a base 9, a support plate 8 is arranged on the base 9, and also includes a power device 5 and a stirring tank 2; the power device 5 is arranged at an angle to the support plate 8, and the stirring tank 2 is eccentrically arranged to the power device 5.

[0023] In the present invention, the base 9 is used as the basis of this solution to stabilize and support other components. Therefore, in actual use, the base 9 can be made of a material with high density, or a weight block can be set on the base 9 to lower the center of gravity of the overall structure and improve the reliability of use. More than one support plate 8 is fixedly set on the base 9. For example, two support plates 8 can be set on the base 9 by welding or other methods, and the two support plates 8 correspond to each other. A power device 5 is set on the support plate 8. In this solution, the power device 5 can be a motor, and the motor is fixed to the support plate 8 by bolt connection. If the axial direction of the motor is set to A, and the direction of the connection between the support plate 8 and the motor along the support plate 8 is B, then A and B are set at an angle, which is generally best at 0-90°.

[0024] In this solution, by adding a support plate 8, the position of the motor can be better adjusted to improve the mixing uniformity. In actual installation, the output end of the motor is connected to a mixing tank 2, wherein the mixing tank 2 can be a rotary structure, including a feed inlet and a discharge port; the axis of the mixing tank 2 is parallel to the axis of the motor but eccentrically arranged.

[0025] The present invention proposes an innovative solution to the problem of uneven stirring of the powder in the stirring tank 2 during the wet treatment of metallic silicon. By eccentrically arranging the stirring tank 2 and the power device 5, the weight of the powder and the centrifugal force generated by the rotation of the stirring tank 2 are utilized to enable the silicon powder that was originally easily pressed at the bottom of the stirring tank 2 to continuously flow out and float to the surface. This eccentric design causes the solution to be in an irregular flow state in the stirring tank 2, thereby effectively impacting the high places and compacting the bottom powder, significantly increasing the fluidity of the powder in the stirring tank 2. Due to the enhanced fluidity of the powder, its contact area and probability with the treatment solution are greatly improved. This means that the effect of the wet treatment will be significantly improved, because more silicon powder can fully react with the solution, thereby improving the purification efficiency. Secondly, the irregular flow generated by the eccentrically arranged power device 5 helps to break the close combination between the powders, reduce the dead corners of stirring, and further improve the uniformity of stirring. Finally, this design also helps to reduce the energy consumption required for magnetic stirring, because the natural effects of gravity and centrifugal force assist the stirring process to a certain extent.

[0026] Furthermore, in other embodiments of the present application, the eccentricity between the stirring tank 2 and the power device 5 is less than 5 cm, and the speed of the motor is 0-200 rpm, which can further improve the purification effect. The following example illustrates that the main impurities of industrial silicon are Fe, Al, Ca, and Ti. The impurity content ppm of the selected sample tested by ICP is:

[0027]

[0028] The sample was evenly divided into three parts, and three methods were used for purification comparison, namely magnetic stirring and mechanical stirring in the prior art, and eccentric stirring in this scheme. During the purification process, the same process was used, that is, the same acid addition amount, sample solid-liquid ratio of 1:4, motor speed of 200rpm, room temperature purification, etc. After purification, the impurity content of each scheme was measured again and shown in the table below.

[0029]

[0030]

[0031] In summary, the eccentric structure involved in this solution can significantly improve the purity of metallic silicon under the same process conditions.

[0032] In other embodiments of the present application, in order to further optimize the connection structure between the stirring tank 2 and the power device 5 and improve the convenience and efficiency of the equipment, a connecting disk 4 can be optionally added between the stirring tank 2 and the power device 5. One end of the connecting disk 4 is tightly connected to the output shaft of the motor, and the other end is firmly connected to the corresponding part of the stirring tank 2, forming a stable and flexible transmission structure. In particular, an eccentric mode can be set on the connecting disk 4, that is, there is an offset between one end of the connecting disk 4 connected to the motor and the other end thereof at the geometric center. By setting the eccentric structure on the connecting disk 4, the connection efficiency between the stirring tank 2 and the power device 5 is significantly improved, ensuring efficient stirring operation.

[0033] In other embodiments of the present application, a frame 3 is coaxially arranged on the periphery of the stirring tank 2. The frame 3 adopts a frame structure, which is not only sturdy in structure, but also easy to assemble and disassemble, greatly improving the installation efficiency of the equipment. The stirring tank 2 is securely placed inside the frame 3, and can be directly connected to the connecting plate 4 through the frame 3, or can be firmly connected to the output end of the motor through the frame 3. Such a design not only simplifies the installation steps and reduces the difficulty of installation, but also effectively enhances the structural stability of the entire stirring equipment by fixing the stirring tank 2 in the frame 3, and can ensure the smooth and safe operation of the equipment even when stirring at high speed or handling heavy loads, further improving the reliability and service life of the equipment.

[0034] Furthermore, in other embodiments of the present application, the power device 5 is fixedly connected to the support plate 8, for example, the motor is fixed to the support plate 8 by welding; this makes the overall structure more stable and reliable. In another embodiment, an adjustment portion 6 is further provided between the power device 5 and the support plate 8. For example, an arc-shaped adjustment hole is provided on the support plate 8, and the adjustment screw is passed through the adjustment hole to connect with the motor, and the position of the bolt in the adjustment hole is changed to adjust the inclination angle between the motor and the support plate 8, which is more convenient to operate.

[0035] In other embodiments of the present application, in order to ensure that the connection between the power device 5 and the support plate 8 is stable and reliable, a variety of fixed connections or detachable connections can be selected. One typical way is to fix the motor directly on the support plate 8 by welding. The welded connection is not only high in strength, but also can effectively resist external vibration and impact, thereby ensuring the stability and durability of the overall structure, so that the mixing equipment maintains excellent performance during long-term operation. In another innovative embodiment, a connection method in which the power device 5 and the support plate 8 are adjusted by the adjustment part 6 can also be selected. Specifically, we cleverly set arc-shaped adjustment holes on the support plate 8, and these adjustment holes allow the position of the motor to be adjusted within a certain range. By adjusting the screws through these arc-shaped adjustment holes and connecting to the motor, the position of the bolts in the adjustment holes can be changed, and then the inclination angle between the motor and the support plate 8 can be accurately adjusted. This structure not only enhances the flexibility of the equipment, making it possible to quickly adjust according to different mixing requirements and working environments, but also greatly improves the convenience of operation and reduces maintenance and use costs.

[0036] Although embodiments of the present invention have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. Eccentric stirring device for purifying metallic silicon, characterized by: The invention comprises a base (9) on which a support plate (8) is arranged, and also comprises a power device (5) and a stirring tank (2); the power device (5) and the support plate (8) are arranged at an angle, and the stirring tank (2) and the power device (5) are arranged eccentrically.

2. The eccentric stirring device for purifying metallic silicon according to claim 1, characterized in that: The eccentricity between the stirring tank (2) and the power device (5) is less than 5 cm.

3. The eccentric stirring device for purifying metallic silicon according to claim 1 or 2, characterized in that: A frame (3) is coaxially arranged outside the stirring tank (2).

4. The eccentric stirring device for purifying metallic silicon according to claim 1 or 2, characterized in that: A connecting plate (4) is also provided between the stirring tank (2) and the power device (5).

5. The eccentric stirring device for purifying metallic silicon according to claim 3, characterized in that: A connecting plate (4) is also provided between the stirring tank (2) and the power device (5).

6. The eccentric stirring device for purifying metallic silicon according to claim 1, 2 or 5, characterized in that: An adjustment portion (6) is also provided between the power device (5) and the support plate (8).

7. The eccentric stirring device for purifying metallic silicon according to claim 3, characterized in that: An adjustment portion (6) is also provided between the power device (5) and the support plate (8).

8. The eccentric stirring device for purifying metallic silicon according to claim 4, characterized in that: An adjustment portion (6) is also provided between the power device (5) and the support plate (8).

9. The eccentric stirring device for purifying metallic silicon according to claim 1, 2 or 5, characterized in that: The power device (5) is fixedly connected to the support plate (8).

Images