Inclined multi-stage slag stopping chute

Abstract

The utility model discloses an inclined multi-stage slag stopping chute which comprises a chute body, and a plurality of slag stopping plates are arranged in the chute body. The two ends of the slag baffle are movably connected to the inner walls of the two sides of the chute body, and the bottom of the slag baffle is connected with the inner bottom of the chute body. An acute angle is formed between the slag baffle and the inner bottom of the chute body; the side face, facing the feeding end of the chute body, of the slag stopping plate is a slag stopping face, a plurality of V-shaped grooves are formed in the slag stopping face from top to bottom, and a slag adhering coating is arranged on the slag stopping face. The slag-liquid separation device is simple in structure, the retention time of silicon liquid in the chute can be prolonged, silicon slag in the silicon liquid is accumulated on the slag stopping face of the slag stopping plate, slag-liquid separation is achieved, the situation that the silicon slag is cast into an ingot mold along with the silicon liquid can be reduced, the product quality is improved, and silicon waste is reduced.

Description

Technical fields:

[0001] This utility model belongs to the field of melt discharge casting technology, specifically relating to an inclined multi-stage slag-blocking chute. Background technology:

[0002] In the industrial silicon smelting process, molten silicon enters a ladle from the furnace for refining. During refining, oxygen is blown in at high temperatures to oxidize impurities such as Al, Ca, and Fe, generating gases or silicon slag, thereby reducing impurities in the molten silicon. After refining, the molten silicon flows out of the ladle and is poured into ingot molds via chutes. The density of liquid silicon is 2.30–2.33 g / cm³. 3 The density of silicon slag is 2.5–2.8 g / cm³. 3 The small density difference means that even after refining and calming, silicon slag remains mixed in with the molten silicon during casting, then flows through a chute into the ingot mold for cooling. The presence of silicon slag in the cooled silicon plate reduces the quality of industrial silicon products.

[0003] Currently, the solution for silicon dross in silicon wafers is to manually break up the cooled wafers, then sort out the pure silicon, and sell the remaining dross. However, during manual sorting, fine particles of pure silicon cannot be collected, and silicon dross often gets mixed into the product, causing a decline in quality. Therefore, removing silicon dross at the upstream stage can reduce downstream product waste and prevent product quality degradation. Utility model content:

[0004] The purpose of this invention is to address the problems mentioned in the background art by providing an inclined multi-stage slag-blocking chute, which reduces the amount of silicon slag poured into the ingot mold along with the molten silicon, thereby improving product quality.

[0005] This utility model is implemented by the following technical solution:

[0006] An inclined multi-stage slag-blocking chute includes a chute body with a plurality of slag-blocking plates disposed within it. The two ends of each slag-blocking plate are movably connected to the inner walls of both sides of the chute body, and the bottom of each slag-blocking plate is connected to the inner bottom of the chute body. An acute angle is formed between the slag-blocking plate and the inner bottom of the chute body. The side of each slag-blocking plate facing the feed end of the chute body is a slag-blocking surface, which has a plurality of V-shaped grooves formed from top to bottom and is coated with a slag-coating layer. Industrial silicon impurities form silicon slag such as Al2O3, CaO, Fe2O3, and SiO2. At around 1500℃, the viscosity of silicon slag is 1-5 Pa·s, while the viscosity of industrial molten silicon is around 0.5 mPa·s. The viscosity of silicon slag is 2000-10000 times that of molten silicon. Therefore, taking advantage of this property, multiple levels of slag-blocking plates are set in the chute body. The surface of the slag-blocking plates has V-shaped grooves and is sprayed with a slag-coating coating. When molten silicon carrying silicon slag is poured from the silicon ladle and cast into the ingot mold through the chute, the low-viscosity molten silicon flows away, while the silicon slag accumulates and adheres to the slag-blocking surface of the slag-blocking plates. After one round of casting is completed, the chute is left to cool. Due to the difference in thermal expansion coefficients between the slag-coating coating and the slag-blocking plates, the silicon slag layer adhering to the surface of the slag-coating coating automatically cracks after cooling, making it easy to clean manually.

[0007] Furthermore, the inner walls on both sides of the chute body are provided with several insertion slots, and the two ends of the slag baffle are provided with tenons that mate with the insertion slots. The tenons slide within the insertion slots. This prevents the slag baffle from falling off when impacted by molten silicon.

[0008] Furthermore, the insertion groove is a dovetail groove, the tenon is a dovetail tenon, and the angle ratio of the dovetail tenon is 1:5 to 1:7.

[0009] Furthermore, the insertion groove is provided with a thermal stress buffer coating, which helps to reduce stress caused by thermal expansion differences.

[0010] Furthermore, the acute angle between the baffle plate and the bottom of the chute body is in the range of 55° to 65°. The baffle plate and the bottom of the chute body have a certain angle of inclination. If the angle is too small, it will be difficult to block the silicon slag, causing most of the slag to flow away with the molten silicon. If the angle is too large, some molten silicon will remain on the bottom side of the baffle plate's baffle surface, making it difficult to separate from the slag even after this portion of molten silicon is poured out. Therefore, through fluid dynamics calculations and experiments, the acute angle between the baffle plate and the bottom of the chute body is designed to be 55° to 65°.

[0011] Furthermore, the height of the baffle plate is 8-10 cm and the thickness is 5-6 cm; the depth of the V-groove is 1-3 mm. If the height of the baffle plate is too small, it will be difficult to block the silicon slag, and most of the silicon slag will flow away with the silicon liquid; if the height of the baffle plate is too large, some silicon liquid will remain on the bottom side of the baffle surface of the baffle plate, and even if this part of the silicon liquid is poured out later, it will be difficult to separate this part of the silicon liquid from the silicon slag.

[0012] Furthermore, several of the slag baffles are equidistantly arranged in the chute body, with the distance between two slag baffles being 5 to 10 cm.

[0013] The advantages of this invention are: It provides an inclined multi-stage slag-blocking chute with a simple structure, convenient operation, and suitability for industrial application. Multiple slag-blocking plates are inclinedly arranged within the chute body. The surfaces of the slag-blocking plates are provided with V-shaped grooves and a slag-coating coating, extending the residence time of the molten silicon within the chute. Silicon slag in the molten silicon accumulates on the slag-blocking surfaces of the plates, achieving slag-liquid separation. This reduces the amount of silicon slag cast into the ingot mold with the molten silicon, improving product quality and reducing silicon waste. Attached image description:

[0014] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 This is a side view schematic diagram of an inclined multi-stage slag-blocking chute.

[0016] Figure 2 This is a schematic diagram of the slag baffle plate.

[0017] Figure 3 This is a top view schematic diagram of an inclined multi-stage slag-blocking chute.

[0018] The attached diagram is described below:

[0019] 1. Sluice box body; 11. Insertion groove; 2. Slag baffle plate; 21. Tenon; 22. V-groove; 23. Slag coating. The hollow arrows in the figure indicate the direction of silicon liquid flow. Detailed implementation method:

[0020] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. In the description of the present utility model, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present utility model. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0021] Example 1

[0022] An inclined multi-stage slag-blocking chute, such as Figure 1-3 As shown: It includes a chute body 1, and seven insertion slots 11 are provided on the inner walls of both sides of the chute body 1; a thermal stress buffer coating (not shown in the figure) is provided in the insertion slots 11. In this embodiment, the thermal stress buffer coating is a boron nitride coating.

[0023] Seven baffle plates 2 are installed inside the chute body 1, with a distance of 5-10 cm between each baffle plate 2. The height of the baffle plate 2 is 8-10 cm and its thickness is 5-6 cm. Each end of the baffle plate 2 has a tenon 21 that mates with a slot 11. The slot 11 is a dovetail groove, and the tenon 21 is a dovetail tenon with an angle ratio of 1:5-1:7. A gap of 0.1-0.3 mm is maintained between the slot 11 and the tenon 21. The tenon 21 slides within the slot 11, allowing the two ends of the baffle plate 2 to be movably connected to the inner walls of both sides of the chute body 1. The bottom of the baffle plate 2 connects to the inner bottom of the chute body 1, forming an acute angle of 60° between the baffle plate 2 and the inner bottom of the chute body 1. The side of the slag baffle 2 facing the feed end of the chute body 1 is the slag baffle surface. The slag baffle surface has six V-shaped grooves 22 from top to bottom. The depth of the V-shaped grooves 22 is 1 to 3 mm. The slag baffle surface is provided with a slag-hanging coating 23. In this embodiment, the slag-hanging coating 23 is an alumina coating.

[0024] The working principle is as follows: When manufacturing the slag baffle 2, the Si3N4+SiN material plate is first cut to the required size, and a V-groove 22 is cut on the slag baffle surface. Then, an aluminum oxide layer is sprayed or brushed onto the slag baffle surface to form a slag-coating coating 23. Insertion grooves 11 are cut into the inner side walls of the chute body 1 according to the design drawing. A layer of boron nitride is sprayed or brushed onto the surface of the insertion grooves 11 to form a thermal stress buffer coating. Before casting, the tenons 21 on both sides of the slag baffle 2 are aligned with the insertion grooves 11 on the inner side walls of the chute body 1. Then, the slag baffle 2 is moved from top to bottom along the insertion grooves 11 into the chute body 1 until the bottom of the slag baffle 2 is connected to the inner bottom of the chute body 1.

[0025] During casting, silicon slag is mixed with molten silicon and poured into the ingot mold via a chute. At around 1500℃, the viscosity of silicon slag is 1-5 Pa·s, and the viscosity of molten silicon is around 0.5 mPa·s. The contact angle of silicon slag on the alumina surface is about 20°, and the contact angle of molten silicon is about 80°. Therefore, during the process of passing through the chute, due to the difference in viscosity and contact angle between silicon slag and molten silicon, coupled with the obstruction of the V-shaped groove 22, the silicon slag basically adheres to and remains on the slag-blocking surface of the slag-blocking plate 2. The molten silicon with the silicon slag basically removed flows along the bottom of the chute body 1 into the ingot mold. After one round of casting is completed, the chute is allowed to cool. Due to the difference in thermal expansion coefficients between the slag coating 23 and the slag-blocking plate 2, the silicon slag layer adhering to the surface of the slag coating 23 automatically cracks after cooling, making it easy to clean manually. Before the next round of casting, spray or brush a layer of alumina on the slag-blocking surface to form a slag-hanging coating 23. If the slag-blocking plate 2 is found to be heavily worn, the worn slag-blocking plate 2 can be removed along the insertion groove 11, and a layer of boron nitride can be sprayed or brushed on the surface of the insertion groove 11 to form a thermal stress buffer coating. Then, the new slag-blocking plate 2 can be inserted into the chute body 1 for use.

[0026] Example 2

[0027] The effectiveness of an inclined multi-stage slag-blocking chute in separating slag and liquid was statistically analyzed. Test subjects included: ① the inclined multi-stage slag-blocking chute of Example 1; ② a chute comprising a chute body. Molten silicon from the same furnace was poured from the silicon ladle into the ingot mold via chute ① or ②, and the results are shown in Table 1. Conventional sluices (i.e., ②) basically fail to block silicon slag. A large amount of silicon slag flows into the ingot mold along with the molten silicon. After cooling and forming, the silicon plates are manually broken into silicon blocks of 1-3 cm. The silicon slag is removed, totaling 0.1190 tons, accounting for 2.18%. This is mainly because the silicon slag contains a certain amount of silicon, making it difficult to separate the silicon slag from pure silicon during manual selection, resulting in some silicon being wasted during the removal of silicon slag. The inclined multi-stage slag-blocking sluice of this application (i.e., ①) can better perform the slag-blocking function. After casting, once the sluice cools, the silicon slag layer adhering to the slag coating surface automatically cracks. The total amount of silicon slag blocked by cleaning and weighing is 0.0313 tons. After the silicon plates in this ingot mold are broken, little or no silicon slag needs to be removed.

[0028] Table 1. Separation effect of different chute sludge and liquid.

[0029] test subjects Volume of molten silicon poured out (tons) Quantity of separated silicon slag (tons) Percentage (%) ① 5.45 0.1190 2.18％ ② 5.32 0.0313 0.59％

[0030] This application can also be used in other melt discharge casting technology fields, and is not limited to the field of silicon casting.

[0031] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A tilting multi-stage slag chute comprising a chute body, characterized by, The chute body is provided with a plurality of slag baffles; the two ends of the slag baffles are movably connected to the inner walls of both sides of the chute body, and the bottom of the slag baffles is connected to the inner bottom of the chute body; an acute angle is formed between the slag baffles and the inner bottom of the chute body; the side of the slag baffles facing the feed end of the chute body is a slag-blocking surface, and the slag-blocking surface is provided with a plurality of V-shaped grooves from top to bottom, and the slag-blocking surface is provided with a slag-coating coating.

2. A tilting multi-stage slag notch according to claim 1, characterized in that, The inner walls on both sides of the chute body are provided with a number of insertion slots, and the two ends of the slag baffle are provided with tenons that cooperate with the insertion slots, and the tenons slide in the insertion slots.

3. The inclined multi-stage slag-blocking chute according to claim 2, characterized in that, The insertion groove is a dovetail groove, the tenon is a dovetail tenon, and the angle ratio of the dovetail tenon is 1:5 to 1:

7.

4. The inclined multi-stage slag-blocking chute according to claim 2, characterized in that, The insertion slot is provided with a thermal stress buffer coating.

5. The inclined multi-stage slag-blocking chute according to claim 1, characterized in that, The acute angle between the slag baffle and the bottom of the chute body is in the range of 55° to 65°.

6. The inclined multi-stage slag-blocking chute according to claim 1, characterized in that, The height of the baffle plate is 8-10cm and the thickness is 5-6cm; the depth of the V-groove is 1-3mm.

7. The inclined multi-stage slag-blocking chute according to claim 1, characterized in that, Several slag baffles are equidistantly arranged in the chute body, and the distance between two slag baffles is 5 to 10 cm.

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