• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    The present invention provides an additive for tin dissolution containing 0.1 to 20% by weight of corrosion inhibitor for copper; and 0.1 to 20% by weight of corrosion inhibitor for nickel; wherein said weight percent is based on the total weight of said additive. The present additive can be used with nitric acid conventionally used for metal dissolution, not only to reduce the use of nitric acid, but also to improve the efficiency of tin dissolution. The present invention also provides a process for tin recycling and a metal recycling reaction vessel. Both favor the need for metal recycling (especially tin recycling) in the department.
    公开号:CH711235A2
    申请号:CH00892/15
    申请日:2015-06-22
    公开日:2016-12-30
    发明作者:Hsu Kenny
    申请人:Uwin Nonotech Co Ltd；
    IPC主号:
    专利说明:

    Technical area
    The present disclosure relates to an additive for metal stripping, particularly for tin stripping.
    State of the art
    [0002] Minerals have been closely linked to the development of human society and natural science since ancient times. Nowadays their importance in the electrical industry of modern technology is even greater. Various elements of the electronics industry, such as a central processing unit (CPU), a printed circuit board, a memory, a flip chip or even a concealed antenna fitted inside the outer shell of a mobile phone, contain metal plate parts. Indeed, those metal plate parts play important roles in the device. Mineral resources, however, are not unlimited; therefore, it has become an essential task in industry in consideration of sustainable development, how to recycle the metal materials from these metal plate parts.
    Conventional forms of recycling for printed circuit boards (PCBs) in the field include methods of incineration, acidification, mechanical physical recycling, etc. In the incineration method, the waste circuit boards shattered at high temperatures are incinerated to decompose and destroy the resin therein and then the Obtain precious metals from it. However, the incineration method may cause air pollution due to the bromine-containing waste gas and dioxin resulting from burning the printed circuit boards. The acidic method is to wash the waste circuit boards with strong acid and then obtain a wash-off solution containing precious metals. Then the precious metals are refined in it using electrolysis or acid-base precipitation processes. In the mechanical-physical recycling method, the waste circuit boards are smashed and the metal materials and non-metal materials are separated according to different densities. Then the metal materials are recycled magnetically. The purity of the metal obtained by this method is too low to be ideal.
    In 2003 the European Union announced the RoHS directives and officially banned electronic products containing lead, which resulted in an increased demand for Pb-free tin paste and thus the price of tin rose significantly. Therefore, a tin recycling method with high recycling efficiency and environmentally friendly properties is urgently needed.
    Summary of the invention
    One of the objects of the present invention is to find a novel additive for tin stripping and a tin stripping solution containing the same, which have good tin stripping efficiency while reducing the amount of nitric acid used; this makes their work process much safer and the environmental impact would be reduced.
    Another object of the present invention is to provide a novel process for the tin recycling method which favors the recycling of tin from waste electronic components with high efficiency and thereby achieves the goal of metal recycling.
    Still another object of the present invention is to provide a novel reaction vessel whose structure has been specially designed for metal recycling and especially for the operation of the above-mentioned tin recycling process.
    In order to achieve the aforementioned goals, the present invention offers an additive for tin stripping, containing:0.1 to 20% by weight of a corrosion inhibitor for copper; and 0.1 to 20% by weight of a corrosion inhibitor for nickel; wherein the remaining weight percent of said tin stripping additive is a solvent; wherein said weight percent is based on the total weight of said tin stripping additive.
    Preferably said corrosion inhibitor for copper is a phosphate salt.
    Preferably said phosphate salt is potassium phosphate, potassium dihydrogen phosphate, dipotassium phosphate, trisodium phosphate, or a combination thereof.
    Preferably said corrosion inhibitor for nickel is sodium oxalate, ammonium chloride, potassium carbonate, sodium metanitrobenzene, or a combination thereof.
    The present invention also provides a solvent for tin stripping containing: 20 to 50% (v / v) of the above-mentioned tin stripping additive; and 20 to 50% (v / v) nitric acid; wherein said% (v / v) is based on the total volume of said solution for tin stripping.
    Said nitric acid preferably has a concentration of 67 to 68% by weight.
    [0014] Said solution for the removal of tin preferably also has a solvent. Preferably said solvent is water.
    The present invention still provides a method of recycling tin, comprising the steps of: (A) immersing an object to be processed in the aforementioned tin stripping solution to obtain a washing-off solution; (B) adding an alkaline solution to said wash-off solution to obtain a precipitate; (C) heating said precipitate; and (D) performing a reduction reaction on said precipitate heated in said step (C) to obtain tin.
    Preferably, said immersion is achieved by placing said object to be processed in a tub of said solution for tin stripping.
    Preferably said tub has a temperature of 20 ° C to 60 ° C.
    Said alkaline solution is preferably a sodium hydroxide solution, potassium hydroxide or a combination thereof.
    Preferably said heating of said step (C) is carried out at a temperature of 600 ° C to 800 ° C.
    Said reduction reaction is preferably carried out by heating said precipitate of step (C) in a gas mixture atmosphere of hydrogen and nitrogen.
    Said gas mixture preferably contains: 20 to 30% (V / V) of hydrogen; and 70 to 80% (v / v) nitrogen; wherein said% (V / V) is based on the total volume of said gas mixture.
    Preferably, said gas mixture is fed to said reduction reaction as a gas stream at a flow rate of 100 to 500 ml / min.
    Preferably said reduction reaction is carried out at a temperature of 200 ° C to 800 ° C.
    Said method preferably also includes a filtration step after said step (A) and before said step (B).
    Preferably said filtration step is a filter paper filtration, a bag filtration, a filtration with filter press, a paddle filtration, a cross-flow filtration, a centrifugal filtration, a Dorr filtration, a hydraulic cyclone filtration, a membrane filtration, or a combination thereof.
    Said method preferably also includes a washing step after said step (B).
    The present invention also provides a reaction vessel comprising a body with an inlet, an outlet, a side wall and a gas inlet; said side wall defining an interior space; wherein a portion of said interior space adjacent said drain is a collection station; a first heater arranged to surround at least portions of said side wall; and a screen mounted within said interior space to divide said interior space into two rooms.
    Preferably, the shape of the body at said collecting station has a conical structure and is connected to said drain.
    Preferably, a collection basin is positioned inside said body at said collection point.
    Preferably said first heating device is in a position relative to said sieve within said interior space.
    Said reaction vessel preferably also has a second heating device; the position of said second heating device corresponding to the position of said collecting station.
    Preferably, said heating device is a blast furnace, a heating band, or a combination thereof.
    Preferably, said sieve has a plurality of pores with an average diameter of 0.1 to 1 mm.
    [0034] Said reaction container preferably also has a gas supply device; said gas supply device being in communication with said gas inlet for supplying gas to said interior space.
    Said reaction vessel is preferably used for refining tin.
    In summary, the present invention provides a tin stripping additive which can be used in conjunction with nitric acid (which is commonly used for metal stripping) as the present tin stripping solution. Use of the present tin stripping additive can advantageously reduce the amount of nitric acid used while maintaining tin stripping efficiency at a desired level; therefore it is gentler on the environment. The present invention also provides a method for recycling tin by means of the use of said tin stripping additive / solution and a reaction vessel which can accordingly be used with said tin recycling process. Said method for recycling tin has the advantages of easy handling and environmental friendliness. The present reaction vessel has a structure specifically designed to handle the recycling process more smoothly.
    Brief description of the figures
    Fig. 1 shows an embodiment of the reaction vessel of the present invention. Fig. 2 shows another embodiment of the reaction vessel of the present invention. Fig. 3 shows the stripping ratio of Samples 1, 3, and 4 of Example 2 of the present invention. Fig. 4 shows the change in the concentration of hydrogen inside said reaction container during the reduction reaction of Example 3 of the present invention. Fig. 5 shows the XRD spectrum of the tin paste obtained in Example 3 of the present invention. (A) Condition 1; (B) Condition 2.
    Detailed Description / Ways of Carrying Out the Invention
    The present invention relates to an additive for tin stripping and a tin stripping solution containing the same. The present invention also relates to a method for tin recycling by means of the use of said tin stripping solution and a reaction vessel which is especially suitable for tin recycling.
    The first aspect of the present invention is an additive for tin stripping which can be used together with nitric acid (which is usually used for metal stripping) as the present tin stripping solution and, meanwhile, the use amount of nitric acid can be reduced. The present tin stripping additive contains 0.1 to 20% by weight of the corrosion inhibitor for copper; and 0.1 to 20% by weight of the corrosion inhibitor for nickel; wherein the remaining weight percent of said tin stripping additive is a solvent; wherein said weight percent is based on the total weight of said tin stripping additive. Said solvent includes, but is not limited to, water. In an alternative embodiment, said tin stripping additive also contains a solvent for the advantageous mixing of said corrosion protection agent for copper and said corrosion inhibitor for nickel. Preferably said solvent is water.
    In an alternative embodiment, said corrosion inhibitor for copper is a phosphate salt. Preferably, said phosphate salt includes, but is not limited to: potassium phosphate, potassium dihydrogen phosphate, dipotassium phosphate, trisodium phosphate, or a combination thereof. In an alternative embodiment, said corrosion inhibitor for nickel includes, but is not limited to: sodium oxalate, ammonium chloride, potassium carbonate, sodium metanitrobenzene, or a combination thereof.
    It is important to note that while the present tin stripping additive is particularly well suited to be used with nitric acid, the use of said tin stripping additive is not so limited. In other words, said tin stripping additive can also be used with other conventionally functioning metal stripping operations to obtain the desired metal stripping effect.
    The second aspect of the present invention is a solvent for tin stripping with 20 to 50% (V / V) of said additive for tin stripping and 20 to 50% (V / V) of nitric acid; wherein said% (v / v) is based on the total volume of said solution for tin stripping. In a preferred embodiment of the present invention, the ratio in volume of said tin stripping additive to said nitric acid is 1: 1; nevertheless, in this preferred embodiment, the present additive for the removal of tin can replace half the amount of nitric acid used and thus significantly reduce the impact on the environment and also the risk of the operation. In an alternative embodiment, the nitric acid used for the preparation of said additive for the removal of tin has a concentration of 67 to 68% by weight; The commercially available nitric acid usually has a concentration of 68% by weight.
    In an alternative embodiment, said tin removal solution also has a solvent. Preferably said solvent is water. Adding a solvent can have some advantages, such as: obtaining a better mixing of said additive for the tin stripping and the nitric acid, and / or increasing the total volume of said tin stripping solution in order to advantageously immerse an object to be processed therein.
    The third aspect of the present invention is a method of recycling tin, comprising the steps of: (A) immersing an object to be processed in said solution for tin stripping to obtain a wash-off solution; (B) adding a basic solution to said wash-off solution to obtain a precipitate; (C) heating said precipitate; and (D) performing a reduction reaction on said precipitate heated in said step (C) to obtain tin.
    In an alternative embodiment, said immersion is achieved in that said object to be processed is placed in a tub of said solution for the tin stripping. In a preferred embodiment, said object to be processed is shaken in said tub in said step (A) in order to facilitate the reaction. In a preferred embodiment, during said immersion in said step (A), a circulating liquid is formed in said tub in order to facilitate the reaction. In an alternative embodiment, said tub has a temperature of 20 ° C to 60 ° C.
    After the processing in said step (A), said object is removed from said tub and said washing-up solution is collected. The resulting wash-off solution contains said tin stripping solution and metallic materials detached from said object. Thereafter, an alkaline solution is added to said washing-up solution to carry out said step (B). A precipitate composed mainly of stannous hydroxide can be obtained while the reaction between said alkaline solution and said washing-off solution is sufficiently carried out. In an alternative embodiment, said alkaline solution is a sodium hydroxide solution, potassium hydroxide or a combination thereof.
    Thereafter, said precipitate is collected and heated in air (step (Q). During the heating, tin (II) hydroxide reacts with the air, resulting in the formation of tin dioxide. In an alternative embodiment, said heating is used Step (C) carried out at a temperature of 600 ° C to 800 ° C.
    Thereafter, a reduction reaction is carried out on said tin dioxide to obtain tin (step (D)). In an alternative embodiment, hydrogen is introduced during said step (D) to allow said tin dioxide to react with hydrogen, as in the following chemical formula, to obtain tin:SnO2 + 2H2- → Sn + 2H2O.
    In a preferred embodiment, said reduction reaction is carried out by heating said precipitate of step (C) in a gas mixture atmosphere of hydrogen and nitrogen. Said gas mixture contains: 20 to 30% (V / V) of hydrogen; and 70 to 80% (v / v) nitrogen; wherein said% (V / V) is based on the total volume of said gas mixture. In an alternative embodiment, said gas mixture is fed to said reduction reaction as a gas stream with a flow rate of 100 to 500 ml / min. Preferably, said gas mixture is continuously fed into said reduction reaction so that the starting chemicals (the left half of the aforementioned chemical equation) are kept in saturation and the reaction is forced towards the right side where the product is formed in order to achieve balance in the Formula to achieve. In a preferred embodiment, said reduction reaction is carried out at a temperature of 600.degree. C. to 800.degree.
    In a preferred embodiment, the present method also includes a filtration step after said step (A) in order to filter out impurities in said washing solution. Said impurities can include precipitate containing silver.
    In a preferred embodiment, the present process also contains a washing step after said step (B). Said washing step consists in adding a large volume of water to said washing-up solution and mixing the two sufficiently so that the sodium salt contained in said washing-up solution can dissolve in the water. A further filtration step can then be carried out in order to separate the solid and liquid components of said washing-up solution.
    In another embodiment, said filtration step is a filter paper filtration, a bag filtration, a filtration with filter press, a paddle filtration, a cross-flow filtration, a centrifugal filtration, a Dorr filtration, a hydraulic cyclone filtration, a membrane filtration, or a combination thereof .
    The fourth aspect of the present invention is a reaction container. In another embodiment, the present reaction vessel is specially designed to work in conjunction with the present method of tin recycling and is therefore especially suitable for the recycling and refining of tin.
    Reference is made to Figures 1 and 2, each showing the two embodiments of the present reaction vessel. The present reaction vessel illustrated in the aforementioned figures comprises: a body 100 having an inlet 101, an outlet 102, a side wall 103, and a gas inlet 104; said side wall 103 defining an interior space 110; wherein a portion of said interior space 110 adjacent said drain is a collection station 111; at least one heating device (first heating device 201 and second heating device 202); and a screen 300 mounted within said interior space 110 and which divides said interior space 110 into two spaces.
    In the embodiments illustrated in Figures 1 and 2, the two bodies 100 differ in the structure of said collecting station 111. In Figure 1, said body 100 is configured as a conical structure 105 at said collecting station 111; wherein the width of said conical structure 105 is successively reduced along the vertical axis of said body and the end of said conical structure 105 is configured to connect with said drain 102. In Figure 2, said body 100 is configured as a sump 106 at said collection station 111; wherein said sump is positioned at said drain 102 to collect products (e.g. tin) and which can be separately removed from said body 100 for delivery of products.
    In the embodiments shown in FIGS. 1 and 2, the two present reaction vessels both have two heating devices 201 and 202. The arrangement is favorable in order to meet different requirements of the reaction temperature in different reaction sections. However, it is also possible for a person skilled in the art to use a single heating device to achieve the heating purposes in the process by adjusting the temperature therein. There are no particular restrictions in the present invention since those skilled in the art can use two or more heating devices for heating different reaction sections.
    Although said first heater 201 and said second heater 202 appear configured from the viewing angle in FIGS. 1 and 2 on the bilateral sides of the body, they are in fact positioned so as to surround at least portions of said sidewall 103. In a preferred embodiment, said first heating device 201 is positioned according to the position of said sieve 300 in said interior space 110. In a preferred embodiment, said second heating device 202 is positioned corresponding to the position of said collecting station 111. In another embodiment, said heating device is a blast furnace, a heating tape, or a combination thereof.
    In a preferred embodiment, said sieve 300 has a plurality of pores, with an average diameter of 0.1 to 1 mm (said pores are not shown in the figures). In a preferred embodiment, said reaction container also has a gas supply device; said gas supply device being in communication with said inlet 104 for supplying the gas into said interior 110.
    Using the tin recycling method as an example, the precipitate obtained from said step (B) of the present method for tin recycling is placed on said sieve 300 for the subsequent processes. The size of said precipitate is larger than the pores of said sieve 300 and it would not fall through them; on the other hand, after the heating in said step (C) and after the introduction of the gas mixture (H2 / N2) through said gas inlet 104 in said step (D) for the reduction reaction, the molten tin can fall through said pores onto said collecting station 111 .
    Example 1: Test 1 for tin stripping efficiency of the present tin stripping solution
    First, the tin stripping additive of the present invention was prepared. A corrosion inhibitor for copper and a corrosion inhibitor for tin were mixed in a solvent as shown in Table 1 below to obtain the present tin stripping additives for this example.
    Table 1: Samples of the present additives for removing tin.
    [0062]
    The following experiments were performed using sample B in Table 1 above. In this example, the efficiency of the tin stripping solution with the present tin stripping additive in the tin stripping was examined. Samples 1 and 2 of the tin stripping solution of this example were prepared as shown in Table 2 below and were used to peel off motherboards (Experiments 1 through 4).
    Table 2: Samples of the present tin stripping solutions. 1 300 mL 300 mL 400 mL 1000 mL 2 250 mL 250 mL 500 mL 1000 mL
    [Experiment 1]
    A motherboard was immersed in said sample 1 at 20 ° C for 30 minutes. The tin stripping solution from sample 1 A successfully stripped the tin from the motherboard in 30 minutes (photos not shown).
    [Experiment 2]
    A motherboard was immersed in said sample 2 at 25 ° C for 20 minutes. The tin stripping solution of sample 2 successfully stripped the tin from the motherboard in 20 minutes (photos not shown). In addition, it was found that the copper layer on the motherboard, the nickel layer on the plug and the legs of the fillet weld of the IC elements were not peeled off by the tin peeling solution. This has shown that with an adequate treatment period, the present tin stripping solution has specificity for tin stripping and would not stripping other metals on the object to be processed. In other words, the tin can then be recycled with improved purity in the tin recycling process.
    [Experiment 3]
    A motherboard was immersed in said sample 2 at 25 ° C for 20 minutes. The tin stripping solution of sample 2 successfully stripped the tin from the motherboard in 20 minutes (photos not shown). In addition, it was found that the copper layer on the motherboard, the nickel layer on the plug and the legs of the fillet weld of the IC elements were not peeled off by the tin peeling solution. This has shown that with an adequate treatment period, the present tin stripping solution has specificity for tin stripping and would not stripping other metals on the object to be processed. In other words, the tin can then be recycled with improved purity in the tin recycling process.
    [Experiment 4]
    Following the above-mentioned experiments 2 and 3, the components of the main circuit boards were additionally immersed in the tin stripping solution of sample 2 at 25 ° C. for 1000 minutes. It was found that the copper layer on the motherboard was peeled off and the legs of the fillet weld of the IC elements were severed, whereas the nickel layer on the connector was still intact (photos not shown).
    Example 2; Tin stripping efficiency test of the present tin stripping solution
    In this example, 6 circuit boards were each immersed in the tin stripping solution of Table 3 at 25 ° C. for 5 minutes. The strip ratio (SR) was calculated using the following formula to compare the tin stripping efficiency of the present tin stripping solutions.
    Table 3: Samples of the present tin stripping solutions. 1 300 mL 300 mL 400 mL 1000 mL 3 500 mL 500 mL 0 mL 1000 mL 4 0 mL 1000 mL 0 mL 1000 mL
    3 shows the separation ratio of samples 1, 3 and 4. The separation ratio of sample 3 was higher than that of sample 4. Sample 4 was not given the present tin-release additive; however, the results of this experiment have shown that adding the present tin stripping additive to replace half the amount of nitric acid can not only reduce the amount of nitric acid used but also increase the stripping efficiency. On the other hand, although the present tin stripping solution from sample 1 was not rated as the best result in the experiment, it was expected that it would be the safest to use because it requires the least nitric acid. Therefore, the example additionally examined the separation ratio of sample 1 by extending the treatment period to see if it could deliver reliable performance.
    The following Table 4 showed that after the treatment period was extended to 10, 20 or 30 minutes, the peeling ratio of sample 1 of the tin peeling solution gradually increased to 100%. This has proven that an excellent separation ratio can also be achieved for sample 1 by slightly extending the treatment period.
    Table 4: The test for the detachment ratio of sample 1. 10 10 20 30 30 100
    Example 3: The tin recycling method of the present invention.
    This example was carried out following Example 2 above to use the wash-off solution obtained by using Sample 1 to peel off circuit boards in the present tin recycling process. Since step (A) of the present process was completed in Example 2, this example started from step (B). Before step (B) was carried out, the said washing-off solution was analyzed by means of SEM-EDS and it was found that it contains the following components: Sn (contained 85.58% by weight), Cu (contained 0.46% by weight), Ag ( contained wt.%), and Na (contained 5.04 wt.%). In order to reduce the amount of silver therein, a filtration step (filter paper filtration) was carried out to remove the silver components therein. Sodium hydroxide was then added to the said washing-up solution until the equivalence point was reached and a precipitate was obtained accordingly. Tin (II) hydroxide was the main component of said precipitate.
    In addition, according to the determination of SEM-EDS, it was expected that said precipitate should also contain a significant amount of sodium component. Therefore, the said precipitate was mixed with a large volume of water and another filtration step (filter paper filtration) was carried out to remove the sodium component therein and obtain a refined precipitate. Another SEM-EDS confirmed that the precipitate contained: Sn (contained 94.76 wt.%), Cu (contained 0.43 wt.%, And Na (contained 4.81 wt.%) However, the aforementioned methods actually removed the silver component, reduced the sodium component and refined the tin component in it.
    Thereafter, said precipitate was dried to obtain a crude product containing tin. Since the main constituent of said precipitate was tin (II) hydroxide, the main constituent of said crude tin-containing product after heating of said step (C) should be tin dioxide. It has been found that the heating of said step (C) can also be carried out in the reaction vessel of the present invention.
    Thereafter, said tin-containing crude product (5 g) was placed on the sieve inside the reaction vessel of the present invention, and a H2 / N2 gas mixture (H2: N2 = 1: 4, volume ratio) was added thereto. A reduction reaction of tin dioxide was carried out at high temperatures using the first heater (i.e., said step (D) of the present invention). Said tin-containing crude product was melted into liquid metal droplets in the reduction reaction at high temperature and fell from the pores of the said sieve into the collecting station of the present reaction vessel. In this example, the procedures were tested according to the conditions listed in Table 5 below to determine the optimal conditions.
    Table 5: The reduction reaction conditions of this example. 1 800 ° C 2500 seconds 2 800 ° C 4500 seconds 3 700 ° C 4500 seconds 4 600 ° C 4500 seconds
    Said gas mixture was continuously added to the reaction and the concentration of H2 inside said reaction vessel was monitored (Fig. 4). The reaction was almost complete when the concentration of H2 inside said reaction vessel approached 20% (v / v). By means of calculations based on the information in FIG. 4, the conditions 1 of Table 5 (time of reaction was 2500 seconds) were insufficient to complete the reaction. The temperature around the collection station of the present reaction vessel was maintained at approximately 300 ° C. by the second heater to ensure that the tin metal droplets remained molten. The weight of the tin mass obtained was determined and listed in Table 6 below, in comparison with a theoretical value.
    Since the main component of said tin-containing crude product was tin dioxide, it was assumed that theoretically every 5 grams of said tin-containing crude product contained 3.93 grams of tin (molecular weight of tin / molecular weight of tin dioxide x 5 g = 3.93 G). According to these results, with the reduction reaction at 800 ° C. (Condition 2), the tin with the highest purity (closest to the theoretical value) was obtained.
    Table 6: the weight of the tin mass obtained under Condition 2, Condition 3 and Condition 4 (the theoretical value is 3.93 grams) 2,800 ° C 3.88 3 700 ° C 4.30 4 600 ° C 4, 89
    In addition, FIGS. 5A and 5B each show the XRD spectrum of the tin mass obtained in said conditions 1 and 2. According to the XRD spectrum, residual tin dioxide was present in the product of Condition 1, indicating that the reaction time was not enough to complete the reaction. In contrast, no tin dioxide remained in the Condition 2 product, indicating that the reaction was completed. In addition, the tin mass of said condition 2 was additionally analyzed by means of SEM-EDS and the results showed that the tin mass contained 99.68% by weight of tin and a small proportion of copper (0.32% by weight). In light of the foregoing, the present tin recycling process has been found to be capable of obtaining high purity tin.
    权利要求:
    Claims (16)
    [1]
    1. A tin dissolving additive containing:0.1 to 20% by weight of a corrosion inhibitor for copper; and0.1 to 20% by weight of a corrosion inhibitor for nickel;wherein the remaining% by weight of said tin dissolving additive is a solvent;wherein said weight% is based on the total weight of said tin release additive.
    [2]
    The tin dissolution additive of claim 1, wherein said copper corrosion inhibitor is a phosphate salt.
    [3]
    The tin dissolution additive of claim 2, wherein said phosphate salt is potassium phosphate, potassium dihydrogen phosphate, dipotassium phosphate, trisodium phosphate, or a combination thereof.
    [4]
    The tin dissolving additive according to claim 1, wherein said corrosion inhibitor for nickel is sodium oxalate, ammonium chloride, potassium carbonate, sodium metanitrobenzene, or a combination thereof.
    [5]
    5. A tin dissolving solution with:20 to 50% (v / v) of the tin releasing additive of claim 1; and20 to 50% (v / v) of nitric acid; wherein said% (V / V) is based on the total volume of said tin dissolution solution.
    [6]
    The tin dissolving solution according to claim 5, wherein said nitric acid has a concentration of 67 to 68% by weight.
    [7]
    The tin dissolution solution of claim 5, further containing a solvent.
    [8]
    The tin dissolution solution according to claim 7, wherein said solvent is water.
    [9]
    9. A process for tin recycling with the following steps:(A) immersing an object to be processed in the tin-dissolving solution according to claim 5 to obtain a washing-off solution;(B) adding an alkaline solution to said wash-off solution to obtain a precipitate;(C) heating said precipitate; and(D) carrying out a reduction reaction of the precipitate heated in step (C) to obtain tin.
    [10]
    The method of claim 9, wherein said dipping is achieved by placing said object to be processed in a pan of said tin dissolving solution.
    [11]
    The method of claim 10, wherein said trough has a temperature of 20 ° C to 60 ° C.
    [12]
    The method of claim 9, wherein said alkaline solution is a caustic soda, potassium hydroxide, or a combination thereof.
    [13]
    The process according to claim 9, wherein said heating of said step (C) is carried out at a temperature of 600 ° C to 800 ° C.
    [14]
    The method of claim 9, wherein said reduction reaction is carried out by heating said precipitate of step (C) in a gas mixture atmosphere of hydrogen and nitrogen.
    [15]
    15. The process of claim 14, wherein said gas mixture contains:20 to 30% (v / v) of hydrogen; and 70 to 80% (v / v) of nitrogen; wherein said% (V / V) is based on the total volume of said gas mixture.
    [16]
    16. A reaction vessel comprising:a body having an inlet, a drain, a sidewall, and a gas inlet; said sidewall defining an interior space; wherein a portion of the interior adjacent to said drain is a collection station;a first heater arranged to surround at least portions of said sidewall; anda screen disposed within said interior space to divide said interior space into two spaces.
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    同族专利:
    公开号 | 公开日
    CH711235B1|2019-05-15|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    法律状态:
    2019-02-28| PK| Correction|Free format text: BERICHTIGUNG INHABER |
    优先权:
    申请号 | 申请日 | 专利标题
    CH00892/15A|CH711235B1|2015-06-22|2015-06-22|Tin dissolving additive and its application.|CH00892/15A| CH711235B1|2015-06-22|2015-06-22|Tin dissolving additive and its application.|
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