An apparatus and method for producing a lead-based master alloy

Abstract

The application relates to a device and a method for preparing a lead-based master alloy, and belongs to the technical field of lead-based master alloys. The device and the method solve the problems of limited product, low quality and high cost of existing lead-based master alloy preparation devices and methods. The device comprises a shell, an inner container arranged in the shell and having an open upper end, an upper cover matched with the open upper end of the inner container, and a liquid discharge pipe. A heating element and a heat preservation layer are arranged between the shell and the inner container, a space for expansion of the heat preservation layer is reserved between the shell and the inner container, and the inner container is made of stainless steel. The upper cover is provided with an anode hole penetrating through the upper cover. One end of the liquid discharge pipe penetrates through the bottom of the shell and then communicates with the bottom of the inner container. The device has a wide application range, low product impurity and low cost.

Description

Technical Field

[0001] This invention relates to the field of lead-based master alloy technology, and more particularly to an apparatus and method for preparing lead-based master alloys. Background Technology

[0002] Lead-based master alloys are materials used to manufacture lead-acid battery grids. Existing lead-based master alloy preparation devices and methods generally fall into two categories: one is the use of an experimental glove box, which produces small quantities and has poor safety; the other is the direct-injection method, in which the required metal is directly added after the lead has been melted and heated to a constant temperature above 600°C, followed by stirring. This method results in significant burn-off. Moreover, both of these devices and methods can only add a portion of the metal (calcium, tin, aluminum, etc.), resulting in uneven content stratification. Adding reactive metals (magnesium, sodium, etc.) is also difficult. Furthermore, these methods suffer from drawbacks such as low first-pass yield, high product impurity content, and high unit power consumption. Summary of the Invention

[0003] In view of the above analysis, the present invention aims to provide an apparatus and method for preparing lead-based master alloys, so as to solve the problems of limited product production, low quality and high cost of existing lead-based master alloy preparation apparatus and methods.

[0004] On one hand, embodiments of the present invention provide an apparatus for preparing lead-based master alloys, the apparatus comprising a shell, an inner liner disposed within the shell and open at the top, an upper cover matching the upper opening of the inner liner, and a drain pipe;

[0005] A heating element and an insulation layer are provided between the shell and the inner liner. Space is reserved between the shell and the inner liner for the expansion of the insulation layer. The inner liner is made of stainless steel.

[0006] The top cover is provided with an anode hole that penetrates through the top cover; one end of the drain pipe penetrates through the bottom of the shell and communicates with the bottom of the inner liner.

[0007] Preferably, the housing includes a first housing and a second housing separated along a tangent passing through the central axis of the housing, and the inner liner is located within a cavity enclosed by the first housing and the second housing; one connecting surface of the first housing and the second housing is connected by a hinge, and the other connecting surface is connected by a fastener.

[0008] Preferably, the fastener includes a bolt, a nut, a spring, and two connecting members, which are respectively disposed on the first housing and the second housing, and the bolt passes through the spring, the two connecting members, and the nut in sequence.

[0009] Preferably, the upper end of the shell is open, and the upper end opening of the shell matches the upper end opening of the inner liner.

[0010] Preferably, the outer wall of the inner liner is provided with a plurality of L-shaped hooks, and the inner walls of the first shell and the second shell are provided with a plurality of reinforcing rods that match the L-shaped hooks. The reinforcing rods are movably connected to the L-shaped hooks in a one-to-one correspondence, and the reinforcing rods and the L-shaped hooks can move relative to each other in a limited horizontal direction.

[0011] Preferably, the heating element includes a vertical heating element that is perpendicular to the bottom of the housing and uniformly disposed around the inner liner, and a horizontal heating element that is parallel to the bottom of the housing and uniformly disposed between the bottom of the inner liner and the bottom of the housing.

[0012] Preferably, temperature sensors are provided in the upper, middle and lower parts of the housing.

[0013] Preferably, the upper cover is further provided with an air inlet and an exhaust outlet that penetrate the upper cover.

[0014] Preferably, the drain pipe is equipped with a lead liquid valve.

[0015] Secondly, embodiments of the present invention provide a method for preparing a lead-based master alloy, the method being carried out in the aforementioned apparatus for preparing a lead-based master alloy, comprising:

[0016] a. Add the raw materials into the inner liner, cover the top, fill the inner liner with slightly positive pressure nitrogen through the air inlet, and expel the oxygen from the inner liner through the exhaust outlet;

[0017] b. The raw materials in the inner liner are heated by a heating element to melt and form molten salt. The anode electrode is inserted into the molten salt through the anode hole, and the inner liner is used as the cathode to carry out electrolysis.

[0018] c. After electrolysis is complete, open the lead liquid valve and drain the lead-based master alloy from the bottom of the inner tank through the drain pipe.

[0019] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0020] 1. The apparatus for preparing lead-based master alloys of the present invention can be used to prepare lead-based master alloys of active metals. The apparatus of the present invention prepares lead-based master alloys by molten salt electrolysis. The active metals in the molten salt form eutectic lead-based master alloys by ion replacement. The metal content can be controlled by the amount of electrolysis, resulting in uniform content, safety and reliability. The molten salt can be reused, making it energy-efficient and convenient for mass production of products with good safety.

[0021] 2. This invention uses a stainless steel inner liner, which not only serves as a container and reaction vessel, but also as a cathode. This avoids the situation where the product is contaminated or even deteriorates due to corrosion and penetration of impurities during high-temperature molten salt electrolysis, making it difficult for the electrolysis to proceed normally. The product has a low impurity content (less than 0.005 wt%) and a high first-pass yield (greater than 99%).

[0022] 3. The present invention uses a heating element between the shell and the inner liner for heating, and reserves space between the shell and the inner liner for the expansion of the insulation layer. The heating element adopts silicon carbide rod radiation heating, controls the high melting point (up to 1000℃), and can be used for a long time below 1000℃.

[0023] 4. The heating element uses silicon carbide rod radiation heating, which avoids the phenomenon of short circuit in the inner tank caused by accidental breakage of heating wire, greatly improving safety and lifespan; after the temperature of this device reaches a stable state, the difference between the displayed temperature and the actual measured temperature inside the furnace is less than 10℃.

[0024] 5. Dividing the shell into a first shell and a second shell not only facilitates opening and closing for maintenance or replacement of the internal structure, but also provides expansion space for the insulation layer to expand under high temperature by setting spring-loaded fasteners.

[0025] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages may become apparent from the description or be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained from what is particularly pointed out in the description and drawings. Attached Figure Description

[0026] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0027] Figure 1 This is a front cross-sectional view of the apparatus for preparing lead-based master alloys according to the present invention;

[0028] Figure 2 This is a top cross-sectional view of the top cover of the present invention;

[0029] Figure 3 This is a top view of the housing of the present invention;

[0030] Figure 4 This is a top view of the arrangement of the heating elements according to the present invention.

[0031] Figure label:

[0032] 1-Shell; 101-First shell; 102-Second shell; 2-Inner liner; 201-Extension section; 3-Top cover; 4-Heating element; 401-Vertical heating element; 402-Horizontal heating element; 5-Insulation layer; 6-Anode hole; 7-Drain pipe; 8-Hinge; 9-Fastener; 10-Bolt; 11-Connector; 12-L-shaped hook; 13-Reinforcing rod; 14-Temperature sensor; 15-Air inlet; 16-Exhaust outlet; 17-Lead liquid valve; 18-Inner liner water cooling ring; 19-Water circulation port; 20-Top cover water cooling ring; 21-Bracket; 22-Roller; 23-Electrode interface. Detailed Implementation

[0033] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which form part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0034] One specific embodiment of the present invention provides an apparatus for preparing lead-based master alloys, such as... Figure 1-4 As shown, the device includes a housing 1, an inner liner 2 disposed inside the housing 1 and open at the top, an upper cover 3 matching the upper opening of the inner liner 2, and a drain pipe 7.

[0035] A heating element 4 and a heat insulation layer 5 are provided between the shell 1 and the inner liner 2. Space is reserved between the shell 1 and the inner liner 2 for the expansion of the heat insulation layer 5. The inner liner 2 is made of stainless steel.

[0036] The upper cover 3 is provided with an anode hole 6 that penetrates the upper cover 3; one end of the drain pipe 7 penetrates the bottom of the shell 1 and communicates with the bottom of the inner liner 2.

[0037] During implementation, the raw materials (pure lead and mixed salt) are added to the inner liner 2, the top cover 3 is placed on top, and the heating element 4 is used to heat the raw materials in the inner liner 2 to melt and form molten salt. The anode electrode is inserted into the molten salt through the anode hole 6, and the inner liner 2 is used as the cathode for electrolysis. After electrolysis, the lead-based master alloy and the molten salt are separated into layers, with the lead-based master alloy located in the lower layer. The lead-based master alloy at the bottom of the inner liner 2 is discharged through the drain pipe 7.

[0038] Compared with existing technologies, the device of this invention can be used to prepare lead-based master alloys of active metals. The lead-based master alloy is prepared by molten salt electrolysis, where the active metals in the molten salt form a eutectic lead-based master alloy through ion replacement. The metal content can be controlled by the amount of electrolysis, resulting in uniform content, safety, and reliability. The molten salt can be reused, making it energy-efficient and convenient for large-scale product preparation with good safety. This invention uses a stainless steel inner liner, which serves not only as a container and reaction vessel but also as a cathode. This prevents product contamination or even deterioration of the molten salt due to corrosion and penetration of impurities during high-temperature molten salt electrolysis, thus avoiding difficulties in the normal electrolysis process. The resulting product has low impurity content and a high first-pass yield.

[0039] It should be noted that the heating element 4 of this invention is a silicon carbide rod. The silicon carbide rod not only ensures efficient radiant heating and stable temperature, but also avoids short circuits in the inner liner caused by accidental breakage of the heating wire, greatly improving the safety and lifespan of the device. Furthermore, the silicon carbide rod has a higher heating temperature and longer service life; the silicon carbide rods are evenly distributed in a ring on the sides and bottom, and do not contact the inner liner, heating the inner liner 2 through thermal radiation. Compared to traditional methods using natural gas for heating and simple electric stoves, where the measured temperature differs from the displayed temperature by 50-100℃, this invention uses silicon carbide rod heating combined with an insulation layer. After the device reaches a stable temperature, the difference between the measured and displayed temperatures is less than 10℃.

[0040] This invention utilizes a heating element between the shell and the inner liner for heating, and reserves space between the shell and the inner liner for the expansion of the insulation layer. The heating element is a silicon carbide rod with radiant heating, controlling a high melting point (up to 1000℃), and can be used for extended periods below 1000℃. Typically, silicon carbide rods can reach 1500℃, and are generally used below 1000℃; while ordinary electric heating wires can only reach 1200℃, and the operating temperature is limited to around 700℃, as the wire will melt at higher temperatures.

[0041] In this invention, the insulation layer 5 is a fire-resistant insulating material, for example, the insulation layer 5 is insulation cotton.

[0042] It is worth noting that the inner liner 2 of this invention does not participate in the reaction and mainly serves a conductive function. The inner liner 2 is made of 316L stainless steel with a composition of 022Cr17Ni12Mo2. This stainless steel can further prevent corrosion and penetration of impurities during high-temperature molten salt electrolysis. Furthermore, the inner liner 2 is cylindrical.

[0043] According to a preferred embodiment of the present invention, the housing 1 includes a first housing 101 and a second housing 102 separated along a tangent passing through the central axis of the housing 1. The inner liner 2 is located within a cavity enclosed by the first housing 101 and the second housing 102. One connecting surface of the first housing 101 and the second housing 102 is connected by a hinge 8, and the other connecting surface is connected by a fastener 9. In this preferred embodiment, the housing 1 is configured as two parts, connected by both the hinge 8 and the fastener 9, facilitating opening and closing for maintenance or replacement of the internal structure. When internal maintenance or replacement of components is required, the housing is opened from the side where the fastener 9 is located, and the first housing 101 and the second housing 102 open and close under the action of the hinge 8. The hinge 8 is a mechanical device used to connect two solids and allow relative rotation between them; its specific structure can be a conventional hinge structure.

[0044] To further promote the long-term use of the device at high temperatures, preferably, the fastener 9 includes a bolt 10, a nut, a spring, and two connecting pieces 11. The two connecting pieces 11 are respectively disposed on the first housing 101 and the second housing 102. The bolt 10 passes through the spring, the two connecting pieces 11, and the nut in sequence. When the device is used at high temperatures, the insulation layer 5 will expand. The first housing 101 and the second housing 102 can be appropriately separated under the action of the spring, providing elastic space for the expansion of the insulation layer 5 and preventing damage to the device due to the expansion of the insulation layer 5.

[0045] Specifically, the connector 11 is a bent structure, with one end for connecting to the housing 1 and the other end having a through hole for the bolt 10 to pass through. The through holes of the two connectors are correspondingly arranged, and the bolt 10 passes through the spring, the through holes of the two connectors 11, and the nut in sequence, thereby connecting the first housing 101 and the second housing 102.

[0046] In this invention, the upper end of the shell 1 is open, and the upper end opening of the shell 1 matches the upper end opening of the inner liner 2.

[0047] Specifically, the first shell 101 or the second shell 102 includes a first horizontal section near the upper opening of the inner liner 2, a vertical section extending downward from the end of the first horizontal section away from the inner liner 2, and a second horizontal section extending from the lower end of the vertical section toward the inner liner 2. The upper opening edge of the inner liner 2 is provided with an extension section 201 extending outward along the upper surface of the first horizontal section. An inner liner water-cooling ring 18 is disposed inside the extension section 201, and the inner liner water-cooling ring 18 surrounds the upper edge of the inner liner. The inner liner water-cooling ring 18 is used to reduce the temperature at the upper end of the inner liner to prevent burns to equipment and personnel. The inner liner water-cooling ring 18 is provided with a water circulation port 19. A heat insulation layer 5 is provided between the first horizontal section and the upper end of the inner liner 2, between the vertical section and the inner liner 2, and between the second horizontal section and the lower bottom of the inner liner 2.

[0048] To prevent deformation of the shell 1 due to the expansion of the insulation layer, multiple L-shaped hooks 12 are provided on the outer wall of the inner liner 2. Multiple reinforcing rods 13, matching the L-shaped hooks 12, are provided on the inner walls of the first shell 101 and the second shell 102. The reinforcing rods 13 and L-shaped hooks 12 are movably connected in a one-to-one correspondence, allowing limited relative movement between the reinforcing rods 13 and L-shaped hooks 12 in the horizontal direction. In this preferred embodiment, when the insulation layer expands due to heat, if the reserved space between the shell 1 and the inner liner 2 is insufficient, the first shell 101 and the second shell 102 will also expand outwards under the expansion of the insulation layer. The reinforcing rods 13 on the shell and the L-shaped hooks 12 on the inner liner can only move relative to each other in the horizontal direction to a limited extent. This ensures that elastic space is provided for further expansion of the insulation layer while preventing deformation of the shell due to excessive expansion, controlling the shell's stretching amplitude while improving its strength.

[0049] Specifically, one end of the L-shaped hook 12 is connected to the outer wall of the inner liner 2, the reinforcing rod 13 is an inverted L-shape, the inverted L-shaped reinforcing rod passes through the insulation layer 5 and is connected to the inner wall of the shell 1, the other end of the L-shaped hook 12 is connected to the other end of the inverted L-shaped reinforcing rod by a hook, and the horizontal section of the L-shaped hook 12 is parallel to and overlaps with the horizontal section of the inverted L-shaped reinforcing rod, ensuring that the reinforcing rod 13 and the L-shaped hook 12 can move relative to each other in the horizontal direction only to a limited extent.

[0050] Furthermore, the reinforcing rod 13 is disposed on the upper part of the first housing 101 and the second housing 102, and the L-shaped hook 12 is disposed in a position corresponding to the reinforcing rod 13.

[0051] To ensure uniform heating of the molten salt in the inner liner 2 and improve heating efficiency, preferably, the heating element 4 includes a vertical heating element 401 that is perpendicular to the bottom of the shell 1 and uniformly arranged around the inner liner 2, and a horizontal heating element 402 that is parallel to the bottom of the shell 1 and uniformly arranged between the bottom of the inner liner 2 and the bottom of the shell 1.

[0052] Specifically, such as Figure 1 and Figure 4 As shown, there are multiple vertical heating elements 401 and multiple horizontal heating elements 402. The multiple vertical heating elements 401 are perpendicular to the bottom of the shell 1 and are evenly arranged around the inner liner 2. The multiple horizontal heating elements 402 are distributed around the center of the bottom of the shell 1. The projection of the multiple vertical heating elements 401 and the multiple horizontal heating elements 402 on the bottom of the shell 1 is spaced apart, which is more conducive to heating efficiency and heating uniformity.

[0053] For example, the heating element 4 also includes an electrode interface 23 disposed at one end of the silicon carbide rod, the electrode interface 23 penetrating the housing 1 for connecting to a power source.

[0054] It is worth noting that, in order to save energy, the vertical heating element 401 is located in the middle and lower part of the outer side of the inner liner 2.

[0055] To effectively control the temperature, preferably, temperature sensors 14 are respectively provided in the upper, middle, and lower parts of the housing 1 to monitor the temperature at the corresponding locations. The two temperature sensors in the middle and lower parts are used for temperature control, while the temperature sensor in the upper part is only used for temperature display at the corresponding location. It should be noted that the upper cover 3 is also provided with an air inlet 15 and an exhaust outlet 16 penetrating through the upper cover 3. The air inlet 15 and the exhaust outlet 16 are used to regulate the pressure of the inner liner 2 and to release oxygen.

[0056] In this invention, the anode hole 6 on the upper cover 3 is used to insert an anode, which can be graphite.

[0057] Furthermore, an insulation layer 5 and a sealing ring are provided between the upper cover 3 and the upper opening of the inner liner 2. An upper cover water-cooling ring 20 is also provided inside the upper cover 3, which is used to ensure effective sealing of the sealing ring and low-temperature operation.

[0058] For example, the anode hole 6 is located at the center of the upper cover 3, and the air inlet 15 and the exhaust port 16 are respectively located on both sides of the anode hole 6 and close to the edge of the upper cover 3. The air inlet 15, the anode hole 6, and the exhaust port 16 are located on a straight line.

[0059] Specifically, such as Figure 2As shown, the upper cover water-cooling ring 20 includes a large ring arranged along the edge of the upper cover 3 and a small ring arranged around the anode hole 6, with the large ring and the small ring connected. This arrangement of the upper cover water-cooling ring 20 can ensure the uniformity of water cooling of the upper cover 3.

[0060] For example, the upper cover water-cooling ring 20 includes a large ring, a first straight segment, a small ring, and a second straight segment. The large ring is arranged along the edge of the upper cover 3. The end of the large ring is connected to the first straight segment extending towards the anode hole 6. One end of the straight segment is connected to the end of the large ring, and the other end is connected to the small ring surrounding the anode hole 6. The end of the small ring is connected to the second straight segment extending towards the edge of the upper cover 3. The air inlet 15 and the exhaust outlet 16 are located between the large ring and the small ring, and the anode hole 6 is located inside the small ring. The large ring and the small ring are relative in terms of their diameter.

[0061] In this invention, the drain pipe 7 is used to drain the lead-based master alloy from the bottom of the inner liner. To control the draining process and avoid the discharge of impurities, preferably, a lead liquid valve 17 is provided on the drain pipe 7. The amount of lead flowing out is controlled by the lead liquid valve 17, so that a small amount (50-100 kg) of lead liquid remains in the inner liner 2. The temperature can also be appropriately lowered to allow the salt to solidify before the lead is released (the melting point of lead is lower than that of salt).

[0062] Considering the relative movement between the first housing 101 and the second housing 102 and the convenience of maintenance, preferably, the device further includes a bracket 21 respectively disposed at the bottom of the first housing 101 and the second housing 102 and a roller 22 disposed at the bottom of the bracket 21. The bracket 21 is used to support the first housing 101 and the second housing 102, and the roller 22 facilitates the opening and closing of the first housing 101 and the second housing 102.

[0063] Secondly, the present invention also provides a method for preparing a lead-based master alloy, the method being carried out in the above-described apparatus for preparing a lead-based master alloy, comprising:

[0064] a. Add the raw materials into the inner liner 2, cover the top cover 3, fill the inner liner 2 with slightly positive pressure nitrogen through the air inlet 15, and exhaust the oxygen in the inner liner 2 through the exhaust outlet 16.

[0065] b. The raw materials in the inner liner 2 are melted by heating element 4 to form molten salt. The anode electrode is inserted into the molten salt through anode hole 6, and the inner liner 2 is used as cathode for electrolysis.

[0066] c. After electrolysis is complete, open the lead liquid valve 17 and drain the lead-based master alloy at the bottom of the inner tank 2 through the drain pipe 7.

[0067] The anode electrode is graphite. During electrolysis, the metals or active metals in the molten salt form a eutectic lead-based master alloy through ion replacement. The metal content is controlled by the amount of electricity used in electrolysis, resulting in uniform content, safety, and reliability. The molten salt can be reused, making it energy-efficient and highly effective. The graphite anode is positioned 2-3 cm above the surface of the molten lead.

[0068] Constant current electrolysis is used, and the current is determined by the anode reaction area (the contact area between the graphite anode and the molten salt). For example, the current density is 1-1.5 A / cm². 2 The electrolysis voltage should not exceed 5V. The temperature should be less than 1000℃, the pressure 0.1-0.5MPa, and the electrolysis charge should be determined according to the required metal content.

[0069] The amount of lead-based master alloy flowing out is controlled by the lead liquid valve 17, so that a small amount (50-100kg) of lead liquid remains in the inner liner 2. The temperature can also be appropriately lowered to solidify the salt, and then the lead is released (the melting point of lead is lower than that of salt).

[0070] The apparatus and method for preparing lead-based master alloys of the present invention will be further illustrated below through specific embodiments.

[0071] Example 1

[0072] An apparatus for preparing a lead-based master alloy includes a shell, an inner liner disposed within the shell and open at its upper end, a top cover matching the upper opening of the inner liner, and a drain pipe. A heating element and an insulation layer are disposed between the shell and the inner liner, with space reserved between the shell and the inner liner for the expansion of the insulation layer. The inner liner is made of stainless steel. The top cover has an anode hole penetrating through it. One end of the drain pipe penetrates the bottom of the shell and communicates with the bottom of the inner liner. The insulation layer is insulation cotton, and the inner liner is a cylindrical 316L stainless steel with a composition of 022Cr17Ni12Mo2. The shell includes a first shell and a second shell separated along a tangent passing through the central axis of the shell. The inner liner is located within a cavity enclosed by the first shell and the second shell. One connecting surface of the first shell and the second shell is connected by a hinge, and the other connecting surface is connected by fasteners. The fasteners include a bolt, a nut, a spring, and two connecting members. The two connecting members are correspondingly disposed on the first housing and the second housing, respectively. The bolt passes through the spring, the two connecting members, and the nut in sequence. Each connecting member has a bent structure; one end of the bent structure connects to the housing, and the other end has a through hole for the bolt to pass through. The through holes of the two connecting members are correspondingly arranged, and the bolt passes through the spring, the through holes of the two connecting members, and the nut in sequence. The upper end of the housing is open, and this upper opening matches the upper opening of the inner liner. The first housing or the second housing includes a first horizontal section near the upper opening of the inner liner, a vertical section extending downwards from the end of the first horizontal section away from the inner liner, and a second horizontal section extending towards the inner liner from the lower end of the vertical section. The upper opening edge of the inner liner has an extension section extending outwards along the upper surface of the first horizontal section. An inner liner water-cooling ring is disposed inside the extension section, and the inner liner water-cooling ring surrounds the upper edge of the inner liner. The inner liner water-cooling ring has a water circulation port. An insulation layer is provided between the upper end of the first horizontal section and the inner liner, between the vertical section and the inner liner, and between the second horizontal section and the bottom of the inner liner. Multiple L-shaped hooks are provided on the outer wall of the inner liner, and multiple reinforcing rods matching the L-shaped hooks are provided on the inner walls of the first and second shells. The reinforcing rods and L-shaped hooks are movably connected in a one-to-one correspondence, allowing limited relative movement between them in the horizontal direction. One end of the L-shaped hook is connected to the outer wall of the inner liner. The reinforcing rod is an inverted L-shape, passing through the insulation layer and connecting to the inner wall of the shell. The other end of the L-shaped hook is connected to the other end of the inverted L-shaped reinforcing rod via a hook, and the horizontal section of the L-shaped hook is parallel to and overlaps with the horizontal section of the inverted L-shaped reinforcing rod. The reinforcing rods are located on the upper part of the first and second shells, with the L-shaped hooks corresponding to the reinforcing rods.The heating elements include vertical heating elements perpendicular to the bottom of the shell and uniformly arranged around the inner liner, and horizontal heating elements parallel to the bottom of the shell and uniformly arranged between the bottom of the inner liner and the bottom of the shell. There are multiple vertical and horizontal heating elements; the multiple vertical heating elements are perpendicular to the bottom of the shell and uniformly arranged around the inner liner, while the multiple horizontal heating elements are radiating outwards around the center of the bottom of the shell. The heating element is a silicon carbide rod, which does not contact the inner liner. One end of the silicon carbide rod has an electrode interface that penetrates the shell for connecting to a power source. The vertical heating elements are located in the middle and lower parts of the outer surface of the inner liner. The projections of the multiple vertical and horizontal heating elements on the bottom of the shell are spaced apart. Temperature sensors are respectively installed in the upper, middle, and lower parts of the shell. The top cover also has an air inlet and an exhaust outlet penetrating through it. A heat insulation layer and a sealing ring are provided between the top cover and the upper opening of the inner liner. A water-cooling ring is also provided inside the top cover. The upper cover water-cooling ring includes a large ring, a first straight segment, a small ring, and a second straight segment. The large ring is positioned along the edge of the upper cover. The end of the large ring connects to the first straight segment extending towards the anode hole. One end of the straight segment connects to the end of the large ring, and the other end connects to the small ring surrounding the anode hole. The end of the small ring connects to the second straight segment extending towards the edge of the upper cover. The air inlet and exhaust outlet are located between the large and small rings, and the anode hole is located within the small ring. A lead liquid valve is installed on the drain pipe. The device also includes supports respectively located at the bottom of the first and second housings, and rollers located at the bottom of the supports.

[0073] Example 2

[0074] Lead-based calcium master alloy (calcium content 2 wt%) was prepared using the apparatus of Example 1.

[0075] Add 1 ton of pure lead and 500 kg of mixed salt (mass ratio CaCl2:CaF2 = 6:1) to the inner liner and cover it with the top cover. Introduce pure nitrogen gas through the air inlet at a pressure of 0.3 MPa and a flow rate of 10 L / min, and expel oxygen from the inner liner through the exhaust port. Set the temperature to 800℃ and melt the lead and salt by heating with a silicon carbide rod. The molten lead and molten salt will separate into layers due to density differences and immiscibility, with the molten lead at the bottom and the molten salt at the top. Insert the graphite anode electrode into the molten salt through the anode hole, with the graphite anode 2 cm above the surface of the molten lead. Connect the graphite anode and cathode inner liner to the positive and negative terminals of the electrolysis power supply, respectively. Use constant current electrolysis, with the current determined by the anode reaction area (the contact area between the graphite anode and the molten salt), and a current density of 1.3 A / cm². 2 The electrolysis voltage is 4V; the electrolysis is completed after the predetermined electrolysis charge of 60000Ah is reached; the lead liquid valve is opened and the lead-based master alloy at the bottom of the inner tank is discharged through the drain pipe. To prevent molten salt from flowing out, 60kg of lead liquid remains in the inner tank.

[0076] During electrolysis, under the influence of electric current, calcium ions in the molten salt gain electrons at the cathode and become metallic calcium. The metallic calcium then enters the lead liquid to form a lead-calcium alloy. At the same time, chloride ions lose electrons at the graphite anode and are released as chlorine gas.

[0077] Reaction equation:

[0078] Anode: 2Cl- - 2e- = Cl2

[0079] Cathode: Ca 2+ +2e-=Ca

[0080] In Example 2, after the temperature reached a stable state, the difference between the displayed temperature and the actual measured temperature inside the furnace was less than 10°C, the impurity content of the lead-calcium alloy product was 0.004%, and the first-pass yield was 99.5%.

[0081] Example 3

[0082] Lead-based sodium master alloy (sodium content 3 wt%) was prepared using the apparatus of Example 1.

[0083] Add 1 ton of pure lead and 500 kg of mixed salt (NaCl:NaCO3 = 2:3 by mass) to the inner liner and cover it with the top cover. Introduce pure nitrogen gas through the air inlet at a pressure of 0.3 MPa and a flow rate of 10 L / min, and expel oxygen from the inner liner through the exhaust port. Set the temperature to 750℃ and melt the lead and salt by heating with a silicon carbide rod. The molten lead and molten salt will separate into layers due to density differences and immiscibility, with the molten lead at the bottom and the molten salt at the top. Insert the graphite anode electrode into the molten salt through the anode hole, with the graphite anode 3 cm above the surface of the molten lead. Connect the graphite anode and cathode inner liner to the positive and negative terminals of the electrolysis power supply, respectively. Use constant current electrolysis, with the current determined by the anode reaction area (the contact area between the graphite anode and the molten salt), and a current density of 1.3 A / cm². 2 The electrolysis voltage is 4V; the electrolysis is completed after the predetermined electrolysis charge of 70000Ah is reached; the lead liquid valve is opened and the lead-based master alloy at the bottom of the inner tank is discharged through the drain pipe. To prevent molten salt from flowing out, 60kg of lead liquid remains in the inner tank.

[0084] During electrolysis, under the action of current, sodium ions in the molten salt gain electrons at the cathode and become metallic sodium. The metallic sodium enters the lead liquid to form a lead-sodium alloy. At the same time, carbonate ions lose electrons at the graphite anode and consume part of the graphite anode to become carbon dioxide and carbon monoxide, which are then discharged.

[0085] Reaction equation:

[0086] Anode: CO3 2- -2e - +C=CO2+CO

[0087] Cathode: Na + +e- =Na

[0088] In Example 3, after the temperature reached a stable state, the difference between the displayed temperature and the actual measured temperature inside the furnace was less than 10°C, the impurity content of the lead-sodium alloy product was 0.003%, and the first-pass yield was 99.6%.

[0089] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. An apparatus for preparing lead-based master alloys, characterized in that, The device includes a housing (1), an inner liner (2) disposed inside the housing (1) and open at the top, an upper cover (3) matching the upper opening of the inner liner (2), and a drain pipe (7). A heating element (4) and a heat insulation layer (5) are provided between the shell (1) and the inner liner (2). A space is reserved between the shell (1) and the inner liner (2) for the heat insulation layer (5) to expand. The inner liner (2) is made of stainless steel. The upper cover (3) is provided with an anode hole (6) that penetrates the upper cover (3); one end of the drain pipe (7) penetrates the bottom of the shell (1) and communicates with the bottom of the inner liner (2); The housing (1) includes a first housing (101) and a second housing (102) separated along a tangent passing through the central axis of the housing (1), and the inner liner (2) is located in a cavity enclosed by the first housing (101) and the second housing (102); one connecting surface of the first housing (101) and the second housing (102) is connected by a hinge (8), and the other connecting surface is connected by a fastener (9); The fastener (9) includes a bolt (10), a nut, a spring, and two connectors (11). The two connectors (11) are respectively disposed on the first housing (101) and the second housing (102). The bolt (10) passes through the spring, the two connectors (11), and the nut in sequence. The outer wall of the inner liner (2) is provided with a plurality of L-shaped hooks (12), and the inner walls of the first shell (101) and the second shell (102) are provided with a plurality of reinforcing rods (13) that match the L-shaped hooks (12). The reinforcing rods (13) are movably connected to the L-shaped hooks (12) in a one-to-one correspondence. The reinforcing rods (13) and the L-shaped hooks (12) can move relative to each other in a limited horizontal direction. The reinforcing rods (13) are inverted L-shaped, and the other end of the L-shaped hooks (12) is connected to the other end of the inverted L-shaped reinforcing rods (13) by means of a hook. The heating element (4) is a silicon carbide rod.

2. The apparatus according to claim 1, characterized in that, The upper end of the shell (1) is open, and the upper end opening of the shell (1) matches the upper end opening of the inner liner (2).

3. The apparatus according to claim 1, characterized in that, The heating element (4) includes a vertical heating element (401) that is perpendicular to the bottom of the shell (1) and uniformly arranged around the inner liner (2) and a horizontal heating element (402) that is parallel to the bottom of the shell (1) and uniformly arranged between the bottom of the inner liner (2) and the bottom of the shell (1).

4. The apparatus according to claim 3, characterized in that, Temperature sensors (14) are respectively provided on the upper, middle and lower parts of the housing (1).

5. The apparatus according to claim 1, characterized in that, The upper cover (3) is also provided with an air inlet (15) and an exhaust outlet (16) that penetrate the upper cover (3).

6. The apparatus according to claim 1, characterized in that, A lead liquid valve (17) is installed on the drain pipe (7).

7. A method for preparing a lead-based master alloy, characterized in that, The method is carried out in the apparatus for preparing lead-based master alloys according to any one of claims 1-6, comprising: a. Add the raw materials into the inner liner (2), cover the top cover (3), fill the inner liner (2) with slightly positive pressure nitrogen through the air inlet (15), and exhaust the oxygen in the inner liner (2) through the exhaust outlet (16); b. The raw materials in the inner liner (2) are melted by heating element (4) to form molten salt. The anode electrode is inserted into the molten salt through anode hole (6) and the inner liner (2) is used as cathode for electrolysis. c. After electrolysis is completed, open the lead liquid valve (17) and discharge the lead-based master alloy at the bottom of the inner liner (2) through the drain pipe (7).

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