A continuous smelting system and method for tin smelting aluminum slag

Abstract

The present invention discloses a continuous smelting system and method for tin smelting aluminum slag. The system comprises an electric furnace, a front bed, and a disc ingot casting machine. The electric furnace is equipped with a feed port, a tin discharge port, and a slag discharge port. The slag discharge port is located 250-350 mm above the tin discharge port, and the angle between the slag discharge port and the horizontal line is 25-30 degrees. The front bed is located below the tin discharge port, and the disc ingot casting machine is located below the tin discharge port of the front bed. The system can achieve multiple tin discharges and a single slag discharge, achieving the purpose of continuous smelting. It has low labor intensity, low investment, minimal safety and environmental risks, and low management difficulty, and has excellent technical and economic indicators.

Description

Technical Field

[0001] The invention belongs to the technical field of nonferrous metal smelting, and in particular relates to a continuous smelting system and a smelting method for tin smelting aluminum slag. Background Art

[0002] The electric furnace is one of the main metallurgical furnaces for tin smelting. The smelting process using the electric furnace has strong adaptability to raw materials and is suitable for processing some high-impurity, high-melting-point, small-batch tin-containing materials. The tin smelting electric furnace has always been responsible for processing aluminum slag, tin-containing intermediate products, return products, and secondary high-impurity tin-containing materials produced by the tin smelting system. With the increasing difficulty of tin mining, the shortage of tin resources, the complex composition of raw materials, and rising prices, the problems will continue to become more prominent, which will cause a backlog of aluminum slag, tin intermediate products, and return products, and occupy a large amount of funds. Therefore, the work of tapping the potential and creating benefits in the treatment of aluminum slag, intermediate products, and return products is urgent. This requires electric furnaces to carry out research on continuous smelting technology for aluminum slag, further expand the processing volume, increase production capacity, effectively reduce the accumulation of intermediate products and return products and capital occupation, reduce production operating costs, tap the potential and create benefits, improve quality and efficiency, and ensure the realization of the goal of high-quality development of tin smelting.

[0003] Furthermore, during the EAF slag tapping process, liquid slag can easily carry tin into the slag pond, increasing the tin content in the slag and affecting technical and economic indicators. Every time crude tin is tapped, workers must clean the front bed and slag pond in advance. This high-temperature environment in the front bed and slag pond creates high labor intensity and presents significant occupational health and safety risks. High-temperature slag requires timely cleaning and transportation, and its storage occupies space. Furthermore, manual slag removal increases the number of workers and poses certain safety risks. Large amounts of high-temperature slag are discharged from the furnace, dissipating a significant amount of heat during the tapping process, causing the furnace temperature to drop, impacting the next cycle of EAF smelting and wasting heat resources. Summary of the Invention

[0004] The purpose of the present invention is to solve the problems existing in the above-mentioned prior art and provide a continuous smelting system and method for tin smelting aluminum slag with low labor intensity, low investment, low safety and environmental protection risks and management difficulty, and good technical and economic indicators.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A continuous smelting system for tin smelting aluminum slag, comprising an electric furnace, a front bed, and a disc ingot casting machine;

[0007] The electric furnace is provided with a feed port, a tin discharge port and a slag discharge port;

[0008] The slag outlet is located 250-350 mm above the tin outlet, and the angle between the center line of the slag outlet and the tin outlet and the horizontal line is 25-30°;

[0009] The front bed is located below the tinning port;

[0010] The disc ingot casting machine is located below the tin discharge port of the front bed.

[0011] The beneficial effects of adopting the above technical solution are as follows: in the traditional tin smelting electric furnace, crude tin and aluminum slag are put into the front bed together, and the high-temperature slag flows into the slag pond through the front bed. The upper surface of the front bed contains a part of slag, and the front bed and slag pond must be cleaned and the slag must be removed each time tin is discharged. The present invention separates the tin discharge port and the slag discharge port of the electric furnace. After the high-temperature liquid tin flows out through the tin discharge port, it enters the front bed and is then cast on the disc ingot casting machine; the high-temperature liquid slag flows out through the slag discharge port and no longer passes through the tin discharge port, which can avoid mechanical inclusions, improve the technical and economic indicators of the electric furnace, and can achieve multiple tin discharges and one-time slag discharges to achieve the purpose of continuous smelting. The slag discharge port and the tin discharge port differ by 250-350mm, which can fully separate the liquid tin and liquid slag, and the liquid tin will not be released during slag discharge.

[0012] Furthermore, in the above-mentioned tin smelting aluminum slag continuous smelting system, it also includes: a batching hopper, an aluminum slag hopper, a conveying device and a screw feeder;

[0013] The batching hopper or aluminum slag hopper is transported to the feeding port of the screw feeder through the conveying device;

[0014] The discharge port of the screw feeder is connected to the feed port of the electric furnace.

[0015] The beneficial effects of the above technical solution are as follows: aluminum slag is fed directly into the electric furnace through the feed port through manual feeding. High pressure must be stopped before operation, and there is a risk of arsine gas poisoning and high-temperature burns (scalds) during operation. The prepared materials and aluminum slag of the present invention can be poured directly into the batching hopper or aluminum slag hopper. When needed, the valve is opened to directly feed the materials into the screw feeder, which then feeds the materials into the electric furnace. This avoids manual feeding in the early stage, achieves uninterrupted high-pressure smelting, reduces labor intensity, improves the working environment, and reduces safety and environmental risks.

[0016] Furthermore, the aluminum slag hopper includes a slag hopper and an exhaust hood covering the top of the slag hopper.

[0017] The exhaust hood completely seals the aluminum slag hopper and feeds the material under negative pressure conditions with exhaust. Arsine gas cannot overflow and the safety risk is low.

[0018] Furthermore, the above-mentioned tin smelting aluminum slag continuous smelting system further includes: a special slag ladle; when the slag is discharged, the special slag ladle is placed below the slag discharge port.

[0019] The dedicated slag bag of this invention prevents water-quenched slag from the slag pond from entering the furnace slag and circulating in the tin smelting system, thereby improving the overall tin smelting recovery rate. This prevents aluminum slag from entering the fore bed along with the molten tin through the tin tap, eliminating the traditional manual cleaning and crushing of the fore bed. The dedicated slag bag is transported to a designated location by slag bag truck for subsequent processing, eliminating the traditional manual lifting of slag and the safety risks of slag lifting and slag ponds.

[0020] The present invention also provides a method for continuously smelting tin smelting aluminum slag, which adopts the above-mentioned system for smelting, comprising the following steps:

[0021] Put the prepared materials into the batching hopper and the aluminum slag into the aluminum slag hopper, and then send them into the electric furnace through the transportation device and the screw feeder for continuous smelting.

[0022] After smelting, the high-temperature liquid tin flows out through the tin tapping port and enters the front bed, and then is cast in the disc ingot casting machine. After multiple tin tappings, the slag is tapped once, and the high-temperature liquid aluminum slag flows into a special slag bag through the slag tapping port.

[0023] Furthermore, quartz or limestone is added to the material to control the silicate acidity K value entering the furnace to be between 0.9 and 1.1 to ensure appropriate slag fluidity.

[0024] Furthermore, the material is fed into the electric furnace at a rate of 2.5-2.6 t / h, and after smelting for 20-30 minutes, aluminum slag is added, and after smelting for another 0.8-1.1 hours, the furnace is probed, and after the liquid tin probe is wrapped with a thickness of ≤3 mm, the tinning port is opened to discharge tin, and the tinning port is closed after the tinning is completed;

[0025] Start the screw feeder and continue to add aluminum slag. After adding, continue smelting for 2.0-2.5 hours and start to probe the furnace. Continue to use the liquid tin probe to probe the furnace, and also use the furnace-specific slag probe to probe the furnace. If the liquid tin probe wrapping thickness is ≤3mm and the furnace-specific slag probe wrapping thickness is >1.8cm, then open the tin opening to release tin, and then continue to add aluminum slag for smelting until the furnace-specific slag probe wrapping thickness is ≤1.8cm. Stop adding aluminum slag, smelt for 1.0-1.2 hours and use the liquid tin probe to probe the furnace. After confirming that all the materials are melted, open the slag opening to release the slag. After the slag is released, open the tin opening to release the tin. When the slag liquid flows out of the tin opening, block the tin opening. After releasing the tin, add the materials again for cycle smelting.

[0026] After the first liquid tin in each cycle flows out from the tin outlet, the slag remaining in the furnace continues to react with the aluminum slag. When the reduction reaction is completed, the tin in the raw material is reduced to liquid tin, and the iron, silicon, calcium and other substances in the raw material slag to form liquid slag. The density of liquid tin is ρ between 6.8-7.2 kg / m 3 The liquid slag density ρ is between 3.9-4.2kg / m 3 The density difference between the two is 2.6-3.3kg / m3 The slag and tin liquid are separated into layers due to their different densities and can be discharged through different discharge ports. After multiple tinning cycles, the slag can be discharged in one go, achieving the goal of continuous smelting. In traditional processes, a large amount of high-temperature slag is discharged from the furnace, which takes away a lot of heat during the slag discharge, causing the furnace temperature to drop, affecting the next cycle of electric furnace smelting and causing heat resource waste. In this invention, after tinning, the aluminum slag remains in the electric furnace, allowing the next smelting cycle to fully utilize the furnace slag temperature, reducing external heating of the electrodes and lowering the unit electricity consumption of the electric furnace.

[0027] The high-temperature liquid tin level in the electric furnace is controlled to be 1-2 cm lower than the slag outlet to prevent the liquid slag from bringing tin into the special slag bag. The tin content in the slag can be controlled to be ≤5%, the direct tin recovery rate of the electric furnace is ≥90.5%, and the tin metal balance is ≥99.2%.

[0028] The beneficial effects of the present invention are as follows:

[0029] (1) Low labor intensity. It reduces the steps of manual feeding, slag removal from the front bed, slag pond cleaning, and slag removal, thus significantly reducing labor intensity.

[0030] (2) Small investment. The equipment used in the tin smelting aluminum slag continuous smelting system of the present invention, the spiral feeder and the special slag bag, are all general equipment with simple structure and low price.

[0031] (3) Safety and environmental protection risks and management difficulty are small. The present invention can prevent personnel from directly putting aluminum slag into the electric furnace, eliminating the risk of arsenic hydrogen gas poisoning and high-temperature burns (scalds) caused by the addition of aluminum slag. The aluminum slag hopper is completely sealed and is fed under negative pressure conditions with ventilation. Arsenic hydrogen gas cannot overflow, and the safety and environmental protection risks are small. The tin smelting electric furnace continuous smelting method of the present invention only needs to focus on the safety management of arsenic hydrogen gas during the pulling and lifting of aluminum slag, which greatly reduces the management area and makes management more convenient.

[0032] (4) Good technical and economic indicators. The aluminum slag feeding process of the present invention no longer requires stopping high pressure, the high-temperature smelting time is extended, and the smelting efficiency is improved. In addition, the tin smelting electric furnace continuous smelting method reduces the number of slag discharges from three times a day to once, and can fully utilize the heat stored in the slag in the furnace to prepare for the next cycle of feeding, effectively improving the heat utilization rate and further enhancing the processing capacity of the electric furnace. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a structural schematic diagram of the continuous smelting system for tin smelting aluminum slag provided by the present invention.

[0034] In the figure: 1- material hopper, 2- screw feeder, 3- aluminum slag hopper, 4- electric furnace, 5- tin outlet, 6- slag outlet, 7- front bed, 8- disc ingot casting machine, 9- special slag bag. DETAILED DESCRIPTION

[0035] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0036] Example 1

[0037] like Figure 1 As shown, this embodiment provides a tin smelting electric furnace continuous smelting system, including a batching hopper 1, an aluminum slag hopper 3, a conveying device and a screw feeder 2, an electric furnace 4, a front bed 7, a disc ingot casting machine 8, and a dedicated slag bag 9. The electric furnace 4 is provided with a feed port, a tin discharge port 5, and a slag discharge port 6. The slag discharge port 6 is located 250-350 mm above the tin discharge port 5, and the angle between the slag discharge port 6 and the tin discharge port 5 and the horizontal line is 25°; the front bed 7 is located below the tin discharge port 5, and the disc ingot casting machine 8 is located below the tin discharge port of the front bed 7. It also includes: the batching hopper 1 or the aluminum slag hopper 3 is conveyed to the feed port of the screw feeder 2 by the conveying device, the discharge port of the screw feeder 2 is connected to the feed port of the electric furnace 4, and the aluminum slag hopper 3 includes a slag hopper and an exhaust hood covering the top of the slag hopper. When discharging slag, the dedicated slag bag 9 is placed below the slag discharge port 6.

[0038] A tin smelting electric furnace continuous smelting method includes the following steps: adding quartz or limestone to the material, controlling the silicate acidity K value of the material entering the furnace to be between 0.9 and 1.1, transporting the material to a screw feeder 2 via a conveyor belt at a rate of 2.5-2.6 t / h, and then feeding the material into an electric furnace 4. After the material is added, it is smelted for 20-30 minutes, and aluminum slag is added. The aluminum slag enters the screw feeder 2 through an aluminum slag hopper 3, and then is automatically transported into the electric furnace 4. After smelting for another 0.8-1.1 hours, the furnace is probed, and after the probe rod is wrapped with a thickness of ≤3 mm, the tinning port 5 is opened to release tin. After the tinning is completed, the tinning port 5 is closed, and the screw feeder 2 is opened to continue adding aluminum slag. After adding, continue smelting for 2.0-2.5 hours and then start to probe the furnace. Continue to use the liquid tin probe to probe the furnace, and also use the furnace-specific slag probe to probe the furnace. If the liquid tin probe wrapping thickness is ≤3mm and the furnace-specific slag probe wrapping thickness is >1.8cm, then open the tin opening to release tin, and then continue to add aluminum slag for smelting until the furnace-specific slag probe wrapping thickness is ≤1.8cm. Stop adding aluminum slag, smelt for 1.0-1.2 hours and then use the liquid tin probe to probe the furnace. After confirming that all the materials are melted, open the slag opening to release the slag. After the slag is released, open the tin opening to release the tin, and block the tin opening when slag liquid flows out of the tin opening. After releasing the tin, add the materials again for cycle smelting.

[0039] After flowing out of the tin tapping port 5, the high-temperature liquid tin enters the front bed 7 and is then cast in the disc ingot casting machine 8. When the slag reaches a certain amount, the high-temperature liquid slag flows out of the slag tapping port 6 and is discharged all at once into a dedicated slag bag 9. The slag bag is then transported to a designated location by a slag bag truck for the next process. Multiple tin discharges and one-time slag discharges can reduce the frequency of slag emptying, fully utilize the heat stored in the slag in the furnace to prepare for the next cycle of charging, play a role in continuous smelting, effectively reduce the tin content in the slag, and improve the direct recovery rate of tin in the electric furnace. The tin content in the slag can be achieved ≤5%, the direct recovery rate of tin in the electric furnace ≥90.5%, and the tin metal balance ≥99.2%.

[0040] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0041] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A continuous smelting system for tin smelting aluminum slag, characterized in that: Including electric furnace, front bed, and disc ingot casting machine; The electric furnace is provided with a feed port, a tin discharge port and a slag discharge port; The slag outlet is located 250-350 mm above the tin outlet, and the angle between the center line of the slag outlet and the tin outlet and the horizontal line is 25-30°; The front bed is located below the tinning port; The disc ingot casting machine is located below the tin discharge port of the front bed; It also includes: a batching hopper, an aluminum slag hopper, a conveying device and a screw feeder; The batching hopper or the aluminum slag hopper is transported to the feeding port of the screw feeder through the conveying device; The screw feeder outlet is connected to the electric furnace inlet; The aluminum slag hopper comprises a slag hopper and an exhaust hood covering the top of the slag hopper.

2. A tin smelting aluminum slag continuous smelting system according to claim 1, characterized in that: Also includes: Special slag bag; the special slag bag is placed below the slag discharge port.

3. A method for continuous smelting of aluminum slag from tin smelting, characterized in that: The smelting is carried out using the system according to any one of claims 1 to 2, comprising the following steps: placing the prepared materials into a batching hopper, placing the aluminum slag into an aluminum slag hopper, and feeding them into an electric furnace through a transport device and a screw feeder in sequence for continuous smelting; After smelting, the high-temperature liquid tin flows out through the tin tapping port and enters the front bed, and then is cast in the disc ingot casting machine. After multiple tin tappings, the slag is tapped once, and the high-temperature liquid aluminum slag flows into a special slag bag through the slag tapping port.

4. The method for continuous smelting of tin smelting aluminum slag according to claim 3, characterized in that: The material is configured with quartz or limestone, and the silica acidity K value entering the furnace is controlled to be between 0.9 and 1.

1.

5. The method for continuous smelting of tin smelting aluminum slag according to claim 3, characterized in that: The material is fed into the electric furnace at a rate of 2.5-2.6 t / h, and after smelting for 20-30 minutes, aluminum slag is added, and the furnace is probed after smelting for another 0.8-1.1 hours. After the liquid tin probe is wrapped with a thickness of ≤3 mm, the tinning port is opened to release tin, and the tinning port is closed after the tinning is completed; Start the screw feeder and continue to add aluminum slag. After adding, continue smelting for 2.0-2.5 hours and start to probe the furnace. Continue to use the liquid tin probe to probe the furnace, and also use the furnace-specific slag probe to probe the furnace. If the liquid tin probe wrapping thickness is ≤3mm and the furnace-specific slag probe wrapping thickness is >1.8cm, then open the tin opening to release tin, and then continue to add aluminum slag for smelting until the furnace-specific slag probe wrapping thickness is ≤1.8cm. Stop adding aluminum slag, smelt for 1.0-1.2 hours and use the liquid tin probe to probe the furnace. After confirming that all the materials are melted, open the slag opening to release the slag. After the slag is released, open the tin opening to release the tin. When the slag liquid flows out of the tin opening, block the tin opening. After releasing the tin, add the materials again for cycle smelting.

6. The method for continuous smelting of tin smelting aluminum slag according to claim 3, characterized in that: The liquid level of the high-temperature liquid tin in the electric furnace is controlled to be 1-2 cm lower than the slag outlet.

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