A method for delaying tin mold oxidation by spraying graphite

Abstract

This invention discloses a method for delaying the oxidation of tin molds by spraying graphite. The method involves uniformly mixing graphite and graphite flux, and then uniformly spraying the mixture onto the inner side of the tin mold. The mass ratio of graphite to graphite flux is 3-4:1-2, and the spray thickness is 0.8-1 mm. This method of spraying graphite onto the surface of the tin mold is simple to operate, avoids direct contact between the inner side of the tin mold and oxygen, and prevents contact between the inner side of the tin mold and water during water cooling. It slows down the oxidation and corrosion rate of the tin mold, extends its service life, reduces the cost of tin refining operations, and significantly reduces the entry of rust and other impurities into the tin ingot, thus improving product quality and enhancing the technical and economic indicators of tin refining.

Description

Technical Field

[0001] This invention relates to the field of metal surface treatment technology, and specifically to a method for delaying the oxidation of tin molds by spraying graphite. Background Technology

[0002] Casting, as the final step in tin smelting, is responsible for ensuring the quality of refined tin products. If rust enters the tin ingot due to corrosion of the tin mold, it may cause appearance quality accidents or refined tin product quality accidents, seriously affecting the company's reputation.

[0003] Tin molds are expensive, costing between 7,000 and 8,000 yuan each. Without coating, they can be used for 2.2 years under normal conditions, but after coating, the lifespan can be extended to more than 3.3 years. This can significantly reduce the operating costs of tin smelting and improve the economic benefits of tin smelting.

[0004] Replacing solder molds is time-consuming, physically demanding, and poses certain safety hazards. Each replacement takes more than 120 hours, each mold weighs 65 kilograms, and loading and unloading require manual operation, necessitating at least 20 people working simultaneously. Furthermore, because the molds are water-cooled, 70% of the screws require open flame heating to remove, posing certain safety risks to the operation.

[0005] Therefore, providing a way to delay the oxidation of tin molds and prevent rust from entering the tin ingots, thereby maximizing the service life of tin molds, is a problem that needs to be solved by those skilled in the art. Summary of the Invention

[0006] The purpose of this invention is to solve the problems existing in the prior art and provide a method for delaying tin mold oxidation by spraying graphite, which is easy to operate, requires little investment, has low safety risk, is easy to manage, and has good technical and economic indicators.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A method for delaying the oxidation of tin mold by spraying graphite, wherein the method involves uniformly mixing graphite and graphite flux and then uniformly spraying the mixture onto the inner side of the tin mold.

[0009] Preferably, the mass ratio of graphite to graphite flux is 3-4:1-2.

[0010] The ratio of graphite solvent to graphite is adjusted to ensure stable and even spraying by the air spray gun, with no liquid flow after spraying.

[0011] Preferably, the graphite flux includes CH3CH(CH3)CH2CH2OOCCH3, which is easily combustible and volatile, allowing the graphite layer to dry quickly after spraying.

[0012] Preferably, the thickness of the spray coating is 0.8-1 mm.

[0013] Preferably, the mixing speed is 2600-2800 r / min and the stirring time is 40-45 min.

[0014] Preferably, the spraying is performed using an air spray gun.

[0015] Preferably, the spraying conditions are as follows: after spraying when the tin mold temperature is 40-50℃, the temperature is raised to 100±5℃ and held for 30 minutes. Finally, the temperature is raised to 120-130℃ and then allowed to cool naturally. At this time, the solvent can evaporate completely and will not enter the tin ingot product during the casting process.

[0016] Preferably, the time to raise the temperature to 100±5℃ is 40-45 minutes, and the time to raise the temperature to 120-130℃ is 25-30 minutes.

[0017] Preferably, the tin mold needs to be polished to meet the St3 standard before spraying.

[0018] Preferably, if rust spots appear inside after spraying, the spraying can be repeated and the coating can be recycled until the coating corrosion is ≥3mm, at which point a new tin mold should be replaced.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] (1) Easy to operate: The raw materials used in this invention can be purchased directly. During the operation, it is only necessary to stir according to the graphite solvent and graphite ratio. Tin mold grinding and tin mold spraying can be done manually. The temperature only needs to reach the spraying and curing temperature. The whole process is easy to operate.

[0021] (2) Low investment: The raw materials used in this invention are inexpensive and used in small quantities. The air gun and mixer can be used for a long time after a one-time purchase.

[0022] (3) Low safety risk: The spraying and curing required by the method of the present invention are not high, and grinding and spraying can be carried out on a fixed platform. The process can be completed by rotating the tin mold, and the safety risk is relatively small.

[0023] (4) Good technical and economic indicators: The method of this invention can extend the service life of tin mold by 50%, greatly reduce the cost of tin refining operations, and prevent rust from entering tin ingots, thereby improving the qualification rate of refined tin products and enhancing the technical and economic indicators of tin refining. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. The drawings in this description are merely embodiments of the present invention.

[0025] Figure 1This is a schematic diagram of the process flow of a method for delaying tin mold oxidation by spraying graphite according to the present invention;

[0026] Among them, 1-graphite solvent, 2-graphite, 3-mixer, 4-air spray gun, 5-tin mold. Detailed Implementation

[0027] Embodiments of the present invention are described below, examples of which are shown in the accompanying drawings. The embodiments described with reference to the drawings are exemplary and intended to explain the present invention, but are not to be construed as limiting the present invention.

[0028] Example 1

[0029] Taking the tin mold of a tin smelter's refining and casting line as the research object, the casting temperature was controlled at the commonly used 340-370℃. The main component of the graphite solvent was CH3CH(CH3)CH2CH2OOCCH3 (content 85%). The graphite was provided by Fuzhou Zhongxin New Material Technology Co., Ltd., batch number ZX-7F-08. Figure 1 The tin mold employs a method for delaying tin mold oxidation by spraying graphite, as provided by this invention, specifically including the following steps:

[0030] The tin mold 5 is manually polished to the St3 standard. Graphite solvent 1 and powdered graphite 2 are poured into the mixer 3 in a 4:1 ratio. The mixer 3 is uniformly controlled at a speed of 2700 r / min and the mixing time is 45 min. After the mixing is completed, the mixture of graphite solvent 1 and graphite 2 is injected into the air spray gun 4 for later use.

[0031] While stirring, heat the tin mold 5 to 50°C and then hold it at that temperature. After the mixture of graphite solvent 1 and graphite 2 is injected into the air spray gun 4, it is evenly sprayed onto the inside of the tin mold 5. Throughout the process, the temperature of the tin mold 5 is controlled at 45-50°C, and the spray thickness is 1mm. After the spraying is completed, the tin mold 5 is heated from 40°C to 100°C over a period of 45 minutes. After reaching 100°C, it is held for 30 minutes, during which time the temperature of the tin mold 5 is 100±5°C. After the holding period, the tin mold 5 is steadily heated to 125°C over a period of 30 minutes. After the tin mold 5 reaches 125°C, the heating is stopped, and it is allowed to cool naturally until the temperature of the tin mold 5 is less than 30°C before normal use. During normal use, pay attention to the equipment. If rust spots are found inside, the above steps can be repeated. The tin mold 5 can be used repeatedly until the wall thickness corrosion is ≥3mm, at which point a new tin mold should be replaced.

[0032] In this embodiment, the average interval for tin mold spraying is 3 months, the tin product return rate is 2%, and the tin mold service life is 4.4 years.

[0033] Example 2

[0034] Taking the tin mold of a tin smelter's refining and casting line as the research object, the casting temperature was controlled at the commonly used 340-370℃. The main component of the graphite solvent was CH3CH(CH3)CH2CH2OOCCH3 (content 85%). The graphite was provided by Fuzhou Zhongxin New Material Technology Co., Ltd., batch number ZX-7F-08. Figure 1 This invention provides a method for delaying tin mold oxidation by spraying graphite, specifically including the following steps:

[0035] The tin mold 5 is manually polished to the St3 standard. Graphite solvent 1 and powdered graphite 2 are poured into the mixer 3 in a 4:1 ratio. The mixer 3 is uniformly controlled at a speed of 2700 r / min and the mixing time is 45 min. After the mixing is completed, the mixture of graphite solvent 1 and graphite 2 is injected into the air spray gun 4 for later use.

[0036] While stirring, heat the tin mold 5 to 45℃ and then hold it at that temperature. After the mixture of graphite solvent 1 and graphite 2 is injected into the air spray gun 4, it is evenly sprayed onto the inside of the tin mold 5. Throughout the process, the temperature of the tin mold 5 is controlled at 40-50℃, and the spraying thickness is 0.8mm. After the spraying is completed, the tin mold 5 is heated, first from 40℃ to 100℃, with a heating time of 45 minutes. After reaching 100℃, it is held at that temperature for 30 minutes, with the temperature of the tin mold 5 at 100±5℃. After the holding time is completed, the tin mold 5 is steadily heated to 130℃, with a heating time of 30 minutes. After the tin mold 5 reaches 130℃, the heating is stopped, and it is allowed to cool naturally until the temperature of the tin mold 5 is less than 30℃ before normal use. During normal use, pay attention to the equipment. If rust spots are found inside, the above steps can be repeated. The tin mold 5 can be used repeatedly until the wall thickness corrosion is ≥3mm, at which point a new tin mold should be replaced.

[0037] In this embodiment, the average interval for tin mold spraying is 2 months, the tin product return rate is 2%, and the tin mold has a service life of 4 years.

[0038] Comparative Example 1

[0039] After the tin mold rusts, it is polished every 0.5 months. No spraying is performed. The rest of the equipment is exactly the same as that used in the example, which specifically includes the following steps:

[0040] After the tin mold 5 is corroded, it should be polished to the St3 standard for normal use. If rust spots are found inside, the tin mold 5 can be polished again to the St3 standard for normal use. It can be used repeatedly until the wall thickness of the tin mold 5 is corroded to ≥3mm, at which point a new tin mold should be replaced. The tin product return rate is 35%, and the tin mold has a service life of 2.2 years.

[0041] Comparative Example 2

[0042] The difference from Example 2 is that the coating thickness is 0.6 mm, but otherwise it is exactly the same as Example 2. The average interval between tin mold coatings is 1.5 months, the tin product return rate is 2%, and the tin product mold service life is 4 years.

[0043] Comparative Example 3

[0044] The difference from Example 2 is that the coating thickness is 1.2 mm, but otherwise it is exactly the same as Example 2. The average interval between tin mold coatings is 4 months, the tin product return rate is 34%, and the tin product mold service life is 4.8 years.

[0045] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method of retarding tin mold oxidation by spray application of graphite, characterized by, The method is to mix graphite and graphite solvent uniformly, and then uniformly spray in the tin mold inside; The mass ratio of the graphite and graphite solvent is 3-4:1-2; The graphite solvent includes CH3CH(CH3)CH2CH2OOCCH3; The spraying condition is that when the tin mold temperature is 40-50℃, the temperature is raised to 100±5℃ after spraying, and then the temperature is kept for 30 min, and finally the temperature is raised to 120-130℃, and then the temperature is naturally reduced.

2. The method of claim 1, wherein the graphite is sprayed. The spraying thickness is 0.8-1mm.

3. The method of claim 1, wherein the graphite is sprayed. The rotation speed for mixing is 2600-2800r / min, and the stirring time is 40-45min.

4. The method of claim 1, wherein the graphite is sprayed. The spraying adopts air spray gun.

5. The method of claim 1 wherein the graphite is sprayed. The temperature raising to 100±5℃ is for 40-45min, and the temperature raising to 120-130℃ is for 25-30min.

6. The method of claim 1, wherein the graphite is sprayed. The tin mold needs to be polished to meet the St3 standard before spraying.

7. The method of claim 1, wherein the graphite is sprayed. After rust points appear in the inside after spraying, the spraying can be repeated, and the new tin mold is replaced when the coating corrosion is greater than or equal to 3mm.

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