A method for separating a tin-lead-bismuth ternary alloy

Abstract

The present application belongs to the technical field of alloy separation, and particularly relates to a separation method of tin-lead-bismuth ternary alloy. The present application provides a separation method of tin-lead-bismuth ternary alloy, comprising the following steps: subjecting a molten tin-lead-bismuth ternary alloy to first fractional crystallization treatment to obtain precipitated crystals and residual liquid; subjecting the precipitated crystals to vacuum distillation to obtain volatiles and refined tin respectively; mixing the volatiles and the residual liquid, and sequentially subjecting to melting treatment and second fractional crystallization treatment to obtain refined bismuth and lead-bismuth alloy respectively. The present application realizes the separation of tin-lead-bismuth ternary alloy by using a physical method, and no new impurities are introduced in the separation process, and the purity of the obtained products is high; and the separation method is simple and suitable for industrial application.

Description

Technical Field

[0001] This invention belongs to the field of alloy separation technology, specifically relating to a method for separating tin-lead-bismuth ternary alloys. Background Technology

[0002] Tin-lead-bismuth ternary alloys are common intermediate products in the smelting of non-ferrous metals such as tin and lead. The traditional separation method is to obtain refined tin and lead-bismuth alloys by vacuum distillation of the tin-lead-bismuth ternary alloys. However, the above method can only separate tin and cannot separate the lead-bismuth alloy.

[0003] Currently, the main method for separating lead-bismuth alloys is wet separation, including chlorination and electrolysis. However, wet separation generates harmful gases and consumes a large amount of energy. Chinese patent CN112899489A discloses a highly efficient lead removal method during bismuth refining. After bismuth slag is smelted, chlorine gas is passed through for preliminary lead removal. The resulting crude bismuth alloy is then subjected to deep lead removal using a combination of borax and a lead-removing agent. The advantage of this method is that it avoids the large-scale use of chlorine gas. However, the above method still suffers from drawbacks such as complex procedures and the introduction of new impurities. Summary of the Invention

[0004] The purpose of this invention is to provide a method for separating tin-lead-bismuth ternary alloys. The separation method provided by this invention is simple and does not introduce new impurities.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] This invention provides a method for separating tin-lead-bismuth ternary alloys, comprising the following steps:

[0007] The molten tin-lead-bismuth ternary alloy was subjected to a first melting and condensation treatment to obtain precipitated crystals and residual liquid;

[0008] The precipitated crystals were subjected to vacuum distillation to obtain volatiles and refined tin, respectively.

[0009] The volatiles and residual liquid are mixed and then subjected to a melt treatment and a second melt-condensation treatment to obtain refined bismuth and lead-bismuth alloys, respectively.

[0010] Preferably, the tin-lead-bismuth ternary alloy melt comprises the following components by mass percentage: 74.01% to 99.99% tin, 0.01% to 11.83% lead, and 0.01% to 14.17% bismuth.

[0011] Preferably, the starting temperature of the first melting and condensation treatment is 230-250°C, and the ending temperature is 160-190°C.

[0012] The first melting and condensation treatment takes 2 to 3 hours.

[0013] Preferably, the vacuum distillation temperature is 900–950°C, the vacuum degree is 5–20 Pa, and the holding time is 40–60 min.

[0014] Preferably, the melting temperature is 350–650°C.

[0015] Preferably, the liquid obtained from the melt treatment comprises the following components by mass percentage: lead 1.0% to 44.4% and bismuth 55.6% to 99.0%.

[0016] Preferably, the starting temperature of the second melting and condensation treatment is 330–360°C, and the ending temperature is 120–150°C;

[0017] The second melting and condensation treatment takes 3 to 1 hour.

[0018] Preferably, the purity of the refined tin is greater than 99.99%.

[0019] Preferably, the purity of the refined bismuth is greater than 99%.

[0020] Preferably, the lead-bismuth alloy comprises, by mass percentage, 40.0% to 44.5% lead and 55.5% to 60.0% bismuth.

[0021] This invention provides a method for separating a tin-lead-bismuth ternary alloy, comprising the following steps: subjecting the molten tin-lead-bismuth ternary alloy to a first melting-condensation treatment to obtain precipitated crystals and residual liquid; subjecting the precipitated crystals to vacuum distillation to obtain volatiles and refined tin; mixing the volatiles and residual liquid, and sequentially subjecting the mixture to a melting treatment and a second melting-condensation treatment to obtain refined bismuth and a lead-bismuth alloy. This invention employs a physical method to separate metallic tin and metallic bismuth from the tin-lead-bismuth ternary alloy, without introducing new impurities during the separation process, resulting in high-purity products; furthermore, the separation method is simple and suitable for industrial applications. Attached Figure Description

[0022] Figure 1 This is a schematic flowchart of the separation method provided by the present invention. Detailed Implementation

[0023] This invention provides a method for separating tin-lead-bismuth ternary alloys, comprising the following steps:

[0024] The molten tin-lead-bismuth ternary alloy was subjected to a first melting and condensation treatment to obtain precipitated crystals and residual liquid;

[0025] The precipitated crystals were subjected to vacuum distillation to obtain volatiles and refined tin, respectively.

[0026] The volatiles and residual liquid are mixed and then subjected to a melt treatment and a second melt-condensation treatment to obtain refined bismuth and lead-bismuth alloys, respectively.

[0027] In this invention, unless otherwise specified, all raw materials are commercially available products well known to those skilled in the art.

[0028] This invention involves subjecting a first melting and condensation treatment of a tin-lead-bismuth ternary alloy molten liquid to precipitated crystals and residual liquid.

[0029] In this invention, the tin-lead-bismuth ternary alloy melt preferably comprises the following components by mass percentage: 74.01% to 99.99% tin, 0.01% to 11.83% lead, and 0.01% to 14.17% bismuth.

[0030] In this invention, the preferred method for preparing the tin-lead-bismuth ternary alloy molten liquid includes:

[0031] The tin-lead-bismuth ternary alloy is melted to obtain the tin-lead-bismuth ternary alloy melt.

[0032] The present invention does not have any special limitation on the source of the tin-lead-bismuth ternary alloy; any source well known to those skilled in the art may be used.

[0033] In this invention, the melting temperature is preferably 350-650°C, more preferably 400-600°C, and even more preferably 450-550°C.

[0034] The present invention does not impose any particular limitation on the melting process; any process well known to those skilled in the art can be used. In the present invention, the melting is preferably carried out in a melting furnace.

[0035] In this invention, the temperature of the tin-lead-bismuth ternary alloy melt during the first melting and condensation treatment is preferably 450°C.

[0036] In this invention, the initial temperature of the first melting and condensation treatment is preferably 230–250°C, more preferably 235–245°C, and even more preferably 238–240°C; the termination temperature is preferably 160–190°C, more preferably 165–185°C, and even more preferably 170–180°C. In this invention, the duration of the first melting and condensation treatment is preferably 2–3 hours. This invention does not impose any particular limitation on the process of the first melting and condensation treatment; any process well-known to those skilled in the art can be used. In this invention, the first melting and condensation treatment is preferably carried out in a refining furnace.

[0037] In a specific embodiment of the present invention, the first melting and condensation treatment preferably includes:

[0038] The molten tin-lead-bismuth ternary alloy was placed in a refining furnace and stirred and cooled in sequence.

[0039] The present invention does not impose any special limitations on the stirring process; any process known to those skilled in the art can be used.

[0040] After the first melting and condensation treatment, the present invention preferably further includes separating the obtained precipitated crystals and residual liquid, and cooling the separated precipitated crystals to room temperature.

[0041] The present invention does not impose any special limitations on the separation and cooling process; any process well known to those skilled in the art can be used.

[0042] After obtaining the precipitated crystal, the present invention performs vacuum distillation on the precipitated crystal to obtain volatiles and refined tin, respectively.

[0043] In this invention, the vacuum distillation temperature is preferably 900–950°C, more preferably 910–940°C, and even more preferably 920–930°C; the vacuum degree is preferably 5–20 Pa, more preferably 8–18 Pa, and even more preferably 10–15 Pa; the holding time is preferably 40–60 min, more preferably 42–58 min, and even more preferably 45–55 min. This invention does not impose any special limitations on the vacuum distillation process; any process well-known to those skilled in the art can be used. In this invention, the vacuum distillation is preferably carried out in a vacuum furnace.

[0044] In this invention, the purity of the refined tin is preferably greater than 99.99%. In this invention, the volatiles preferably include lead and bismuth.

[0045] After obtaining the volatiles and the residual liquid, the present invention mixes the volatiles and the residual liquid, and performs a melting treatment and a second melting and condensation treatment in sequence to obtain refined bismuth and lead-bismuth alloy, respectively.

[0046] The present invention does not impose any special limitations on the mixing process; any process known to those skilled in the art can be used.

[0047] In this invention, the temperature of the melting treatment is preferably 350–650°C, more preferably 400–600°C, and even more preferably 450–550°C. This invention does not impose any particular limitation on the melting treatment process; any process well-known to those skilled in the art can be used. In this invention, the melting treatment is preferably carried out in a smelting furnace.

[0048] In this invention, the liquid obtained from the melt treatment preferably includes the following components by mass percentage: lead 1.0% to 44.4% and bismuth 55.6% to 99.0%.

[0049] In this invention, the temperature of the liquid obtained from the melting process during the second melting and condensation process is preferably 450°C.

[0050] In this invention, the initial temperature of the second melting and condensation treatment is preferably 330–360°C, more preferably 335–355°C, and even more preferably 340–350°C; the termination temperature is preferably 120–150°C, more preferably 125–145°C, and even more preferably 130–140°C. In this invention, the duration of the second melting and condensation treatment is preferably 3–4 hours. This invention does not impose any special limitations on the process of the second melting and condensation treatment; any process well-known to those skilled in the art can be used. In this invention, the second melting and condensation treatment is preferably carried out in a refining furnace.

[0051] In a specific embodiment of the present invention, the second melting and condensation treatment is preferably:

[0052] The liquid obtained from the melting process is placed in a refining furnace and stirred and cooled in sequence.

[0053] The present invention does not impose any special limitations on the stirring process; any process known to those skilled in the art can be used.

[0054] Following the second melting and condensation treatment, the present invention preferably further includes separating and cooling the obtained refined bismuth and lead-bismuth alloy. The present invention does not impose any particular limitation on the separation and cooling process; any process well-known to those skilled in the art can be used.

[0055] In this invention, the purity of the refined bismuth is preferably greater than 99%.

[0056] In this invention, the lead-bismuth alloy preferably comprises the following components by mass percentage: 40.0% to 44.5% lead and 55.5% to 60.0% bismuth. In this invention, when the mass percentage of lead is 44.5% and the mass percentage of bismuth is 55.5%, the lead-bismuth alloy is a lead-bismuth eutectic alloy.

[0057] The separation method provided by this invention is a continuous production process that is green and pollution-free. The separated products can be sold directly, realizing the high-value utilization of raw materials. It is an economical, efficient and environmentally friendly alloy separation method.

[0058] To further illustrate the present invention, a method for separating a tin-lead-bismuth ternary alloy provided by the present invention will be described in detail below with reference to the accompanying drawings and embodiments, but these should not be construed as limiting the scope of protection of the present invention.

[0059] Example 1

[0060] 250 kg of tin-lead-bismuth alloy (containing 81.7% tin, 7.8% lead, and 10.5% bismuth by mass percentage) was heated to 500°C to fully melt it, resulting in a tin-lead-bismuth ternary alloy melt. After the temperature of the tin-lead-bismuth ternary alloy melt stabilized at 450°C, it was transferred to a refining furnace. In the refining furnace, the melt was stirred and allowed to stand and cool down for the first melting and condensation treatment. The initial temperature was 240°C and the final temperature was 170°C. During the cooling process, the precipitated slag was removed and cooled to room temperature to obtain precipitated crystals and residual liquid.

[0061] The precipitated crystals were placed in a vacuum furnace and vacuum distilled at a temperature of 930℃ and a vacuum degree of 10Pa for 50 minutes to obtain volatiles and refined tin (purity of 99.995%).

[0062] The obtained volatiles and residual liquid were mixed and placed in a melting furnace and heated to 500°C to fully melt them. After the temperature of the molten liquid stabilized at 450°C, it was transferred to a refining furnace. In the refining furnace, the molten liquid was stirred and allowed to stand and cool down for a second melting and condensation treatment. The initial temperature was 340°C and the final temperature was 130°C. The slag precipitated during the cooling process was removed and cooled to obtain refined bismuth (purity of 99.1%) and lead-bismuth alloy (containing 44.5% lead and 55.5% bismuth by mass percentage, i.e., lead-bismuth eutectic alloy).

[0063] The flowchart of the separation method provided in this embodiment is shown below. Figure 1 As shown.

[0064] Example 2

[0065] 250 kg of tin-lead-bismuth alloy (containing 81.7% tin, 7.8% lead, and 10.5% bismuth by mass percentage) was heated to 500°C to fully melt it, resulting in a tin-lead-bismuth ternary alloy melt. After the temperature of the tin-lead-bismuth ternary alloy melt stabilized at 450°C, it was transferred to a refining furnace. In the refining furnace, the melt was stirred and allowed to stand and cool down for the first melting and condensation treatment. The initial temperature was 240°C and the final temperature was 180°C. The slag precipitated during the cooling process was removed and cooled to room temperature to obtain precipitated crystals and residual liquid.

[0066] The precipitated crystals were placed in a vacuum furnace and vacuum distilled at a temperature of 930℃ and a vacuum degree of 15Pa for 50 minutes to obtain volatiles and refined tin (purity of 99.993%).

[0067] The obtained volatiles and residual liquid were mixed and placed in a melting furnace and heated to 500°C to fully melt them. After the temperature of the molten liquid stabilized at 450°C, it was transferred to a refining furnace. In the refining furnace, the molten liquid was stirred and allowed to stand and cool down for a second melting and condensation treatment. The initial temperature was 350°C and the final temperature was 140°C. The slag precipitated during the cooling process was removed and cooled to obtain refined bismuth (purity of 99.3%) and lead-bismuth alloy (containing 43.8% lead and 56.2% bismuth by mass percentage).

[0068] Example 3

[0069] 250 kg of tin-lead-bismuth alloy (containing 81.7% tin, 7.8% lead, and 10.5% bismuth by mass percentage) was heated to 500°C to fully melt it, resulting in a tin-lead-bismuth ternary alloy melt. After the temperature of the tin-lead-bismuth ternary alloy melt stabilized at 450°C, it was transferred to a refining furnace. In the refining furnace, the melt was stirred and allowed to stand and cool down for the first melting and condensation treatment. The initial temperature was 240°C and the final temperature was 185°C. During the cooling process, the precipitated slag was removed and cooled to room temperature to obtain precipitated crystals and residual liquid.

[0070] The precipitated crystals were placed in a vacuum furnace and vacuum distilled at 920℃ and 15Pa for 50 minutes to obtain volatiles and refined tin (purity 99.991%).

[0071] The obtained volatiles and residual liquid are mixed and placed in a melting furnace, heated to 500°C to fully melt them. After the temperature of the molten liquid stabilizes at 450°C, it is transferred to a refining furnace. In the refining furnace, the molten liquid is stirred and allowed to stand and cool down for a second melting and condensation treatment. The initial temperature is 360°C and the final temperature is 150°C. The precipitated slag during the cooling process is removed and cooled to obtain refined bismuth (purity of 99.1%) and lead-bismuth alloy (containing 40.3% lead and 59.7% bismuth by mass percentage).

[0072] Example 4

[0073] 250 kg of tin-lead-bismuth alloy (containing 81.7% tin, 7.8% lead, and 10.5% bismuth by mass percentage) was heated to 500°C to fully melt it, resulting in a tin-lead-bismuth ternary alloy melt. After the temperature of the tin-lead-bismuth ternary alloy melt stabilized at 450°C, it was transferred to a refining furnace. In the refining furnace, the melt was stirred and allowed to stand and cool down for the first melting and condensation treatment. The initial temperature was 240°C and the final temperature was 190°C. During the cooling process, the precipitated slag was removed and cooled to room temperature to obtain precipitated crystals and residual liquid.

[0074] The precipitated crystals were placed in a vacuum furnace and vacuum distilled at a temperature of 910℃ and a vacuum degree of 15Pa for 50 minutes to obtain volatiles and refined tin (purity of 99.991%).

[0075] The obtained volatiles and residual liquid were mixed and placed in a melting furnace and heated to 500°C to fully melt them. After the temperature of the molten liquid stabilized at 450°C, it was transferred to a refining furnace. In the refining furnace, the molten liquid was stirred and allowed to stand and cool down for a second melting and condensation treatment. The initial temperature was 360°C and the final temperature was 160°C. The slag precipitated during the cooling process was removed and cooled to obtain refined bismuth (purity of 99.1%) and lead-bismuth alloy (containing 43.3% lead and 56.7% bismuth by mass percentage).

[0076] Comparative Example 1

[0077] 250 kg of tin-lead-bismuth alloy (containing 81.7% tin, 7.8% lead, and 10.5% bismuth by mass percentage) was heated to 500°C to fully melt it, resulting in a tin-lead-bismuth ternary alloy melt. After the temperature of the tin-lead-bismuth ternary alloy melt stabilized at 450°C, it was transferred to a refining furnace. In the refining furnace, the melt was stirred and allowed to stand and cool down for the first melting and condensation treatment. The initial temperature was 220°C and the final temperature was 190°C. During the cooling process, the precipitated slag was removed and cooled to room temperature to obtain precipitated crystals and residual liquid.

[0078] The precipitated crystals were placed in a vacuum furnace and vacuum distilled at 900℃ and 30Pa for 50 minutes to obtain volatiles and refined tin (purity 90.983%).

[0079] The obtained volatiles and residual liquid were mixed and placed in a melting furnace and heated to 500°C to fully melt them. After the temperature of the molten liquid stabilized at 450°C, it was transferred to a refining furnace. In the refining furnace, the molten liquid was stirred and allowed to stand and cool down for a second melting and condensation treatment. The initial temperature was 340°C and the final temperature was 130°C. The slag precipitated during the cooling process was removed and cooled to obtain refined bismuth (purity of 99.1%) and lead-bismuth alloy (containing 44.3% lead and 45.7% bismuth by mass percentage).

[0080] Comparative Example 2

[0081] 250 kg of tin-lead-bismuth alloy (containing 81.7% tin, 7.8% lead, and 10.5% bismuth by mass percentage) was heated to 500°C to fully melt it, resulting in a tin-lead-bismuth ternary alloy melt. After the temperature of the tin-lead-bismuth ternary alloy melt stabilized at 450°C, it was transferred to a refining furnace. In the refining furnace, the melt was stirred and allowed to stand and cool down for the first melting and condensation treatment. The initial temperature was 240°C and the final temperature was 170°C. During the cooling process, the precipitated slag was removed and cooled to room temperature to obtain precipitated crystals and residual liquid.

[0082] The precipitated crystals were placed in a vacuum furnace and vacuum distilled at a temperature of 930℃ and a vacuum degree of 10Pa for 50 minutes to obtain volatiles and refined tin (purity of 99.995%).

[0083] The obtained volatiles and residual liquid were mixed and placed in a melting furnace and heated to 500°C to fully melt them. After the temperature of the molten liquid stabilized at 450°C, it was transferred to a refining furnace. In the refining furnace, the molten liquid was stirred and allowed to stand and cool down for a second melting and condensation treatment. The initial temperature was 320°C and the final temperature was 150°C. The slag precipitated during the cooling process was removed and cooled to obtain refined bismuth (purity of 95.5%) and lead-bismuth alloy (containing 38.2% lead and 61.8% bismuth by mass percentage).

[0084] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. Other embodiments can be obtained based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for separating a tin-lead-bismuth ternary alloy, characterized by, Includes the following steps: The molten tin-lead-bismuth ternary alloy was subjected to a first melting and condensation treatment to obtain precipitated crystals and residual liquid; the initial temperature of the first melting and condensation treatment was 230-250℃, and the final temperature was 160-190℃. The precipitated crystals were subjected to vacuum distillation to obtain volatiles and refined tin, respectively. The volatiles and residual liquid are mixed and then subjected to a melt treatment and a second melt-condensation treatment to obtain refined bismuth and lead-bismuth alloys, respectively. The starting temperature of the second melting and condensation treatment is 330–360°C, and the ending temperature is 120–150°C.

2. The separation method according to claim 1, characterized in that, The tin-lead-bismuth ternary alloy melt comprises the following components by mass percentage: 74.01%–99.99% tin, 0.01%–11.83% lead, and 0.01%–14.17% bismuth.

3. The separation method according to claim 1, characterized in that, The first melting and condensation treatment takes 2 to 3 hours.

4. The separation method according to claim 1, characterized in that, The vacuum distillation temperature is 900–950℃, the vacuum degree is 5–20 Pa, and the holding time is 40–60 min.

5. The separation method according to claim 1, characterized in that, The melting temperature is 350–650°C.

6. The separation method according to claim 1, characterized in that, The liquid obtained from the melt treatment comprises the following components by mass percentage: lead 1.0% to 44.4% and bismuth 55.6% to 99.0%.

7. The separation method according to claim 1, characterized in that, The second melting and condensation treatment takes 3 to 4 hours.

8. The separation method according to claim 1 or 4, characterized in that, The purity of the refined tin is greater than 99.99%.

9. The separation method according to claim 1 or 7, characterized in that, The purity of the refined bismuth is greater than 99%.

10. The separation method according to claim 9, characterized in that, The lead-bismuth alloy comprises, by mass percentage, 40.0% to 44.5% lead and 55.5% to 60.0% bismuth.

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