A production method and equipment for removing bismuth and silver from lead smelting

Abstract

The invention relates to the technical field of crude lead smelting, and in particular to a production method and equipment for a bismuth-removing and silver-removing agent for lead smelting. The bismuth-removing and silver-removing agent for lead smelting is composed of a bismuth-removing layer and a silver-removing layer sequentially consolidated on the outer surface of a substrate. The production method of the bismuth-removing and silver-removing agent for lead smelting comprises the following specific steps: step one: material preparation: weighing a bismuth-removing raw material and a silver-removing raw material as needed and mixing them respectively; step two: consolidation of the bismuth-removing layer: preparing a substrate, spraying a sintering layer containing the bismuth-removing raw material outside the substrate and sintering in isolation to form a bismuth-removing layer; step three: consolidation of the silver-removing layer: spraying a sintering layer containing the silver-removing raw material outside the bismuth-removing layer and sintering in isolation to form a silver-removing layer; step four: after the bismuth-removing layer and the silver-removing layer are cooled to room temperature, the bismuth-removing and silver-removing agent for lead smelting is obtained. A production equipment for the bismuth-removing and silver-removing agent for lead smelting is also provided, which is used for one-step production of molding and sintering of a large-diameter lead smelting bismuth-removing and silver-removing agent.

Description

Technical Field

[0001] The invention relates to the technical field of crude lead smelting, and in particular to a production method and equipment for a bismuth and silver removal agent for lead smelting. Background Art

[0002] The refining of crude lead is mainly divided into pyro refining and electrolytic refining. Pyro refining has the advantages of small footprint, simple equipment, short production cycle, and easy product diversification. The process of pyro refining of lead mainly includes copper removal, arsenic, antimony, tin removal, silver removal, zinc removal, bismuth removal, final refining and ingot casting, among which silver and bismuth are difficult to remove.

[0003] In the prior art, when refining crude lead after copper, arsenic, antimony and tin are removed, it is necessary to add impurity removers (silver removers and bismuth removers), which are mainly added to the molten lead liquid in the form of powder or solid. The main difficulty is that the density of these impurity removers is very different from that of lead, and they tend to float on the surface of the lead liquid, and they are seriously oxidized by contact with air, so the impurity removers are usually added by adding lead alloys. However, such an addition method usually requires a large amount of lead to be added to the lead melting pot in the form of alloys. For example, in order to maintain the stability of calcium and magnesium in the lead liquid, a lead alloy containing 1% calcium is usually added to the lead melting pot, which requires the addition of a large amount of lead alloy. Usually, 13 to 15 tons of lead alloy are needed to refine 100 tons of lead to make the impurity removers sufficient. Such a method not only generates a large amount of raw material accumulation and occupation, but also generates considerable fire consumption. If the lead liquid is added in the form of calcium-magnesium alloy blocks, the calcium-magnesium alloy blocks only slowly dissolve but do not melt. The speed is very slow, the processing time is long, and the high temperature requires a large amount of fuel for heating, resulting in a high cost of lead pyrometallurgical refining. Summary of the invention

[0004] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a method and equipment for producing a bismuth-removing and silver-removing agent for lead smelting. The bismuth-removing and silver-removing agent for lead smelting produced by the method can be dissolved in lead liquid at a reasonable speed, and gradually release effective impurity-removing components, thereby improving material utilization, solving product quality problems, and effectively reducing production costs.

[0005] The present invention is realized by the following technical scheme: a production method of a bismuth-removing and silver-removing agent for lead smelting, the bismuth-removing and silver-removing agent for lead smelting is a solid spherical preparation, the solid spherical preparation is based on the outer surface of the substrate to solidify the bismuth-removing layer and the silver-removing layer in sequence; the bismuth-removing layer and the silver-removing layer both contain a metal mixture and a slag-reducing material; the bismuth-removing layer also includes a calcium compound;

[0006] The production method of the lead smelting bismuth and silver removal agent comprises the following specific steps:

[0007] Step 1: preparing materials: weighing a bismuth-removing raw material and a silver-removing raw material as needed and mixing them separately, wherein the bismuth-removing raw material and the silver-removing raw material are both ground into 100-200 meshes;

[0008] Step 2: Consolidation of the bismuth removal layer: prepare a substrate, spray a sintering layer containing a bismuth removal raw material on the outside of the substrate and sinter with oxygen isolation, and the sintering temperature is 580° C. to 620° C.; wherein the metal mixture in the bismuth removal raw material contacts and eutectics to form a network skeleton, and the calcium compound and the slag material constitute entrained components, and the entrained components are dispersed in the skeleton to form a bismuth removal layer;

[0009] Step 3: consolidation of the desilvering layer: spraying a sintering layer containing a desilvering raw material on the bismuth layer and sintering with oxygen isolation, the sintering temperature is 400° C. to 420° C., the metal mixture in the desilvering raw material contacts and eutectics to form a mesh skeleton, and the slag material forms an entrained component, and the entrained component is dispersed in the skeleton to form a desilvering layer;

[0010] Step 4: After the bismuth removal layer and the silver removal layer are cooled to room temperature, the lead smelting bismuth removal and silver removal agent is obtained.

[0011] In the prior art, various impurity removers are usually added directly in the form of metal blocks (usually calcium and magnesium metal blocks) or in the form of alloy blocks of the metal and lead. When added in the form of metal blocks, an immersion cage or a pressing device must be used to press the block metal into the lead liquid. At this time, since the melting point of the impurity remover is higher than the melting point of the lead liquid, the metal block only dissolves but does not melt, and the speed is very slow. Increasing the temperature can accelerate the dissolution, but increasing the temperature will also cause calcium to oxidize and burn in the air, resulting in a large amount of raw material loss. Metals added in the form of alloys (such as lead-calcium alloys) ), will melt quickly because of its lower melting point than lead, dissolving calcium in the lead liquid. Such calcium can react quickly in the lead liquid, but in order to achieve a suitable reaction speed, a large amount of lead is needed in the lead-calcium alloy. Usually, 13% to 15% of the total weight of crude lead is added to meet the requirements. This requires a large amount of alloy to be added, which not only generates a large amount of fire consumption, but also requires a very large alloy storage space. If added in the form of powder (metal compound), the added powder will float on the surface of the lead liquid because the density is less than that of lead, and it is difficult to enter the lead liquid, and then it will be entrained by the slag and no longer contact the lead liquid, resulting in waste.

[0012] The present invention adopts a sintering method to make the metal components of the bismuth removal layer and the silver removal layer contact each other during the sintering process to form an alloy eutectic region with a relatively low melting point. The powder particle size is very small, has a high surface energy, and the contact area between the particles is also very small. The total surface area is large and is in a high energy state. During the sintering process, the system will spontaneously change to the lowest energy state, thereby realizing the densification process. Low-melting-point substances in the metal mixture are precipitated, and part of the precipitated phases are concentrated and distributed at the grain boundaries, surrounding the grains to form obvious grain boundaries. After sintering, a three-dimensional network skeleton structure is formed, and the infusible parts of the components are dispersed in the skeleton structure to form a spherical blended material. This The skeleton of the mesh structure is pressed into the lead liquid by an immersed cage, and the part in contact with the lead liquid can quickly dissolve and release the entrained part. The skeleton part, due to its loose structure, dissolves faster than the block metal in the prior art, and releases the entrained part into the lead liquid. After releasing the entrained part, the skeleton part can contact the lead liquid more to transfer heat and continue to dissolve or melt quickly. Such a lead smelting bismuth and silver removal agent can be dissolved in the lead liquid at a reasonable speed, and does not need to be added in the form of lead alloy. Only the main materials are added, which greatly reduces the weight of the raw materials, and does not cause waste of raw materials due to the addition of powder floating on the surface of the lead liquid, thereby reducing the cost of pyrometallurgical refining.

[0013] After the lead smelting bismuth and silver removal agent of the present invention is added to the lead liquid, while the pseudo-boehmite decomposes to generate water molecules, the calcium-magnesium alloy and the bismuth in the lead generate Bi3Ca and Bi3Mg2 slag shells that are insoluble in lead and have a density lower than that of lead. Since the present invention uses an immersion cage to fix the bismuth removal agent at the bottom of the bismuth removal pot, the disturbance caused by the slow overflow process of water molecules in the lead liquid can prolong the contact time between the calcium-magnesium alloy and the bismuth in the lead, and ensure the full contact between the calcium-magnesium alloy and the bismuth in the lead liquid, thereby improving the bismuth removal effect.

[0014] Furthermore, the substrate is a sphere that is insoluble in lead liquid and does not react with lead liquid, and the substrate is made of stainless steel or alumina ceramics, and the substrate is preferably an alumina ceramic ball.

[0015] Furthermore, the metal mixture in the bismuth removal raw material includes aluminum powder, metal magnesium particles, metal calcium particles, and metal antimony particles, the calcium compound includes calcium chloride powder and calcium carbide powder, the slag reduction material includes fluorite powder and pseudo-boehmite, and the components are arranged in descending order by volume as follows: aluminum powder, metal magnesium particles, metal calcium particles, metal antimony particles, calcium chloride powder, calcium carbide powder, fluorite powder, pseudo-boehmite, and the sum of the volumes of the aluminum powder, metal magnesium particles, and metal calcium particles accounts for 60% to 80% of the total volume of the bismuth removal layer raw material.

[0016] When calcium and magnesium are present, adding antimony can remove bismuth to any desired degree (K. Mallaley et al., "Analysis of the Betterton-Kroll Process: Removal of Bismuth from Crude Lead", Nonferrous Metallurgy). Therefore, the present invention selects aluminum, metal magnesium, metal calcium and metal antimony as skeleton components, and calcium chloride powder, calcium carbide powder, fluorite powder and pseudo-boehmite as entrained components. On the one hand, the part where antimony contacts with metal aluminum, metal magnesium and metal calcium can form a low melting point area, and a sintering state can be achieved at a lower temperature, thereby increasing the speed of metal skeleton formation and reducing consumption. On the other hand, such a metal skeleton is easier to melt and dissolve in lead liquid, thereby increasing the speed at which the raw materials enter the lead liquid. The calcium chloride powder and calcium carbide powder, as the entrained parts, can enter the lead liquid when the skeleton is dissolved (or melted), react with aluminum or lead to generate calcium or lead-calcium combination, and also produce a bismuth removal effect. The specific reaction is as follows:

[0017] 3CaCl2+2Al=3Ca+2AlCl3

[0018] 8Al+3CaC2=2Al4C3+3Ca

[0019] 3Pb+CaC2=Pb3Ca+2C

[0020] Ca + 3Pb = Pb3Ca

[0021] Pb3Ca+3Bi=Bi3Ca+3Pb

[0022] Compared with the prior art, the dissolution of metallic calcium in the skeleton of the lead smelting bismuth and silver removal agent of the present invention and the release of calcium chloride and calcium carbide in the entrained part enhance the dispersion of calcium in the lead liquid, increase the contact opportunity of calcium with bismuth, silver and antimony, and improve the bismuth removal effect.

[0023] Aluminum dissolves very little in lead (the solubility is about 0.005% at 350°C), and most of it enters the slag and does not need to be removed separately, which further improves the impurity removal effect of calcium in the lead liquid. At the same time, the skeleton dissolution (or melting) rate is moderate, and calcium forms a long-lasting release process in the lead liquid, which enhances the bismuth removal effect. The main component of fluorite powder is calcium fluoride, which helps to melt and reduce slag in metal smelting, improves metal fluidity, and reduces slag inclusions. Pseudo-boehmite is an aluminum oxide crystal containing crystal water molecules. It will dehydrate to form γ-Al2O3 when roasted at 450°C to 700°C, and become a porous adsorption material. It acts as a slag reducer to promote the separation of lead liquid and slag.

[0024] Furthermore, the metal mixture in the desilvering raw material includes zinc powder and aluminum powder, and the slag-reducing material includes fluorite powder and pseudo-boehmite. The components are arranged in descending order by volume as follows: zinc powder, aluminum powder, fluorite powder, pseudo-boehmite, and the sum of the volumes of the zinc powder and the aluminum powder accounts for 60% to 80% of the total volume of the desilvering layer raw material.

[0025] Silver and zinc can form a silver-zinc shell with high melting point and low density, floating on the surface of molten lead. Excess zinc and silver that cannot be reacted with zinc also form intermetallic compounds with calcium and magnesium, such as MgAg with a melting point of 1088K and AgCa with a melting point of 993k, which can effectively remove silver from lead.

[0026] Under the premise that alkali metals can also remove silver, the present invention still chooses to make a silver removal layer outside the bismuth removal layer because the silver removal layer of the present invention also has another purpose, namely, isolation. The silver removal layer of the present invention can isolate the bismuth removal layer from contact with the air, avoid oxidation of calcium and magnesium in the bismuth removal layer, and avoid water absorption and decomposition of calcium carbide. Because the calcium and magnesium in the present application are sintered in the state of metal elements, a part of the calcium and magnesium particles that are in contact with each other form a lower temperature eutectic region, but there is still a part of the calcium and magnesium that exist alone and need to be isolated from the air to avoid oxidation failure.

[0027] The skeleton components in the silver removal layer are zinc powder and aluminum powder. On the one hand, zinc powder has the function of removing silver, and the zinc powder has a low melting point, and forms a low melting point area with aluminum to produce a sintering effect. The solubility of aluminum powder in lead liquid is very small, and basically only cooling is needed to remove the aluminum in the lead. After aluminum is precipitated in the lead, it floats on the surface, which can separate the slag from the lead liquid, play a role in filtering the lead liquid and slag, reduce the slag production, reduce the amount of lead liquid entrained in the slag, and make the slag easier to pick up. In addition, the aluminum powder also plays a role in increasing the metal component and the skeleton volume, and minimizes the addition of zinc, so that the zinc content after silver removal is still insufficient to reach the concentration that needs to be removed separately. Then, in the process of removing bismuth, alkali metals and their compounds have a certain effect of removing zinc (recorded in "Nonferrous Metal Metallurgy", compiled by the Japan Metal Society and translated by Xu Xiuzhi, pages 163-164, Metallurgical Industry Press, August 1988). The present invention does not require separate zinc removal, and reduces the operation process steps.

[0028] Furthermore, the oxygen-insulated sintering method is radiation heating sintering.

[0029] By using radiation heating, only a small area is heated up, and the heating and cooling speeds are fast. Only a very small amount of pseudo-boehmite is decomposed by heat, and most of the pseudo-boehmite is not affected.

[0030] Through experiments, it was found that the volume and structure of the bismuth and silver removing agent for lead smelting have a certain influence on its effect. For example, when the diameter of the bismuth and silver removing agent for lead smelting is small, more bismuth and silver removing agent spheres are needed. They are piled up in the immersion cage, and the outer layer of the pile is dissolved first, while the time for the inner layer of the pile to change is delayed, resulting in overlapping of bismuth removal and silver removal. Not only is it difficult to distinguish between silver slag and bismuth slag after slag removal, which is inconvenient for later classification and recovery, but the alkali metal in the bismuth removal layer that is preferentially dissolved in the outer layer of the pile also consumes the zinc in the silver removal layer that is delayed in dissolving in the inner layer of the pile, resulting in incomplete bismuth and silver removal and a lot of raw material waste. Therefore, the present invention adopts large-diameter spheres to increase the volume of the lead smelting bismuth and silver removing agent and reduce the number to avoid the above problems. The matrix of the present invention is based on the effect of increasing the volume of the spheres on the one hand, and on the other hand, it is also for the convenience of making bismuth and silver removing agent spheres for lead smelting.

[0031] The existing technology is not suitable for producing large-diameter lead smelting bismuth and silver removal agent spheres, so a device capable of producing large-diameter spherical multilayer structures is needed.

[0032] A production device for a bismuth-removing and silver-removing agent for lead smelting, comprising a shell, a feeding part, a heating part and a supporting roller group, wherein the shell has a connecting pipe for vacuuming, and a supporting roller group is arranged in the shell, wherein the supporting roller group is composed of three supporting rollers, and the three supporting rollers enable a substrate to produce horizontal rotation during a vertical rolling process, wherein the feeding part is located outside the shell and has a feeding pipe extending into the shell, wherein the feeding part sprinkles bismuth-removing raw materials onto the surface of the substrate and silver-removing raw materials onto the surface of the bismuth-removing layer through the feeding pipe, wherein the heating method of the heating part is radiation heating, and the heating part is inclined toward a projection area of ​​the feeding pipe on the surface of the substrate.

[0033] By using radiation heating, at the same mass fraction, the smaller the particle size, the greater the number of particles, the greater the probability of reflection and scattering of electromagnetic waves in the medium, and the various absorption effects can be fully exerted. After the raw material absorbs the radiation energy, the molecules and atoms inside it vibrate faster and produce resonance, thereby increasing the thermal motion energy and causing the temperature to rise. Since the melting points of calcium-magnesium-aluminum alloy and zinc-aluminum in the raw materials are relatively low, they preferentially form liquid alloys, and high-melting-point substances are dispersed in the liquid alloy. As the cooling process proceeds, the infusible part will eventually be dispersed in the calcium-magnesium-aluminum alloy metal matrix or the zinc-aluminum alloy metal matrix to form a spherical shell-shaped blended material.

[0034] The three support rollers of the present invention can make the substrate produce horizontal rotation during the rolling process in the vertical direction. When the substrate rotates, each point on the substrate surface has the opportunity to face upward. Both feeding and radiation heating can be fixed at specific positions. The substrate surface can be fed and heated only by fixing it, which greatly simplifies the equipment structure.

[0035] Furthermore, two of the three support rollers produce a vertical rolling effect on the base, and the other support roller not only produces a vertical rolling effect on the base but also makes the base produce a rotation tendency in the horizontal direction, that is, two of the three support rollers are on a vertical plane, and the plane where the other support roller is located is at an angle to the vertical direction.

[0036] Furthermore, the feeding part includes two storage bins, a screw conveyor and a feeding pipe, the two storage bins are storage spaces with a accommodating cavity, the top of the storage bin is provided with a cover, the screw conveyor connects the two storage bins, the middle part of the screw conveyor is connected to the feeding pipe, and the feeding pipe is a double-layer or multi-layer tubular body.

[0037] Furthermore, a reflective cover is provided on the heating part, and the reflective cover concentrates the radiation area of ​​the heating part on the surface of the substrate, and the radiation area wraps the projection of the feeding tube on the surface of the substrate.

[0038] Because radiation heating is used and the radiation area is concentrated in a fixed-direction area on the surface of the substrate, only the area facing the heating part is heated up, while other parts not subject to radiation are cooled down. This facilitates rapid heating and sintering and cooling of the sphere, and is beneficial for the rapid formation of a spherical structure. Sintering and wrapping are carried out simultaneously, and multiple processes are carried out at the same time, which saves process time and does not require the use of adhesives in advance to shape the shape.

[0039] Since the workshop takes a long time to process molten lead, one device can meet the supply of bismuth and silver removal agents for lead smelting in multiple lead melting pots. It does not require other equipment such as molding (ball making), sintering, cooling, etc., reducing cost investment.

[0040] The beneficial effects of the present invention are:

[0041] The present invention adopts a sintering method to make the metal components in the bismuth removal layer and the silver removal layer contact each other to form an alloy eutectic region with a relatively low melting point. After sintering, a three-dimensional network skeleton structure is formed to wrap the infusible part. Such a structural network skeleton is pressed inside the lead liquid by an immersed cage, and can be quickly dissolved or melted when in contact with the lead liquid, releasing the entrained part. The skeleton part can contact the lead liquid more and continue to be quickly dissolved or melted, and can be dissolved in the lead liquid at a reasonable speed, which can ensure that metal elements such as calcium and magnesium are quickly dissolved in the lead liquid and diffuse upward from the bottom of the lead liquid with stirring. Compared with adding in the form of lead-calcium alloy, the present invention does not require a large amount of alloy, nor does it require excessive fire consumption. Compared with adding in the form of powder, the present invention has less loss, and the added elements such as calcium and magnesium do not need to be too excessive as in the prior art, but only slightly excessive.

[0042] The present invention uses the metal parts in the bismuth removal layer material and the silver removal layer material as the main skeleton raw materials, and other materials with relatively high melting points as entrained materials. The skeleton melting point of the bismuth removal layer is higher than that of the silver removal layer, so that the materials of each layer are released step by step, and each raw material for removing impurities is also accompanied by the release of slag reduction components when added, so that impurity removal and slag reduction are carried out simultaneously, thereby reducing the entrainment of lead liquid in the slag, and better achieving the bismuth removal and silver removal effects.

[0043] The present invention adopts an immersion cage to fix the bismuth and silver removal agent for lead smelting at the bottom of the lead liquid, which can overcome the technical problem in the prior art that the bismuth removal agent and the slag reduction agent have low densities and the added amounts of the bismuth removal agent and the slag reduction agent are greater than the theoretical values, thereby greatly reducing the added amount of the bismuth removal agent; in addition, the bismuth removal agent is fixed by the immersion cage, which can prolong the contact time and path of the relevant components in the bismuth removal agent and the impurities in the lead liquid, thereby promoting the bismuth removal, silver removal and slag reduction effects.

[0044] The production equipment for the bismuth and silver removing agent for lead smelting of the present invention can realize the one-step production of the bismuth and silver removing agent for lead smelting with a large diameter, does not need the participation of too much equipment, and uses the bismuth and silver removing agent for lead smelting with a larger weight and a smaller number to remove bismuth and silver, thereby avoiding the accumulation of a large number of small-diameter additives, achieving the separation of bismuth removal and silver removal, avoiding the mutual interference between bismuth removal and silver removal, enabling the slag phases to be distinguished, and facilitating the later recovery of components in the slag; the structure is simple, and the wrapping and sintering are carried out simultaneously, thereby avoiding a large number of equipment occupying the production space. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 This is a schematic structural diagram of a bismuth and silver removal agent for lead smelting according to the present invention;

[0046] Figure 2 It is a structural schematic diagram of a production device for removing bismuth and silver from lead smelting according to the present invention;

[0047] Figure 3 It is a sectional front view of a production device for removing bismuth and silver from lead smelting according to the present invention;

[0048] Figure 4 yes Figure 3 AA section view;

[0049] Figure 5 It is a motion state diagram of the substrate on the support roller group.

[0050] Among them: 1. shell; 2. feeding part; 3. heating part; 4. support roller group; 5. connecting pipe; 6. storage bin; 7. screw conveyor; 8. feeding pipe; 9. sealing cover; 10. substrate; 11. bismuth removal layer; 12. silver removal layer. DETAILED DESCRIPTION

[0051] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0052] A method for producing a bismuth-removing and silver-removing agent for lead smelting, wherein the bismuth-removing and silver-removing agent for lead smelting is a solid spherical preparation, and the solid spherical preparation is composed of a bismuth-removing layer 11 and a silver-removing layer 12 sequentially solidified on the outer surface of a substrate 10; the bismuth-removing layer 11 and the silver-removing layer 12 both contain a metal mixture and a slag-reducing material; the bismuth-removing layer 11 also contains a calcium compound;

[0053] The production method of the lead smelting bismuth and silver removal agent comprises the following specific steps:

[0054] Step 1: Prepare materials: weigh bismuth removal raw materials and silver removal raw materials as needed and mix them separately;

[0055] The raw materials of the bismuth removal layer 11 include aluminum powder, metal magnesium particles, metal calcium particles, metal antimony particles, calcium chloride powder, calcium carbide powder, fluorite powder, and pseudo-boehmite in descending order, and the sum of the volumes of the aluminum powder, metal magnesium particles, and metal calcium particles accounts for 60% to 80% of the volume of the raw materials of the bismuth removal layer 11;

[0056] The mass of magnesium in the bismuth removal layer 11 is calculated by the weight of metal magnesium particles, and the mass of calcium is calculated by the sum of the weights of calcium elements in metal calcium particles, calcium chloride powder, and calcium carbide powder. The weight ratio of calcium to magnesium is 5:12.

[0057] The raw materials of the silver removal layer 12 include zinc powder, aluminum powder, fluorite powder, and pseudo-boehmite in descending order, and the volume sum of the zinc powder and the aluminum powder accounts for 60% to 80% of the total volume of the raw materials of the silver removal layer 12;

[0058] The bismuth removal raw material and the silver removal raw material are ground into 100-200 meshes;

[0059] Step 2: Consolidation of the bismuth-removing layer: prepare a substrate 10, which is an alumina ceramic ball that is insoluble in lead liquid and does not react with lead liquid. Spray a sintering layer containing a bismuth-removing raw material on the outside of the substrate 10 and sinter it in an oxygen-proof manner. In this embodiment, the bismuth-removing raw material sprinkled from the feeding tube falls on the surface of the substrate 10 to form a sintering layer, and the sintering temperature is 580° C. to 620° C.; wherein the metal mixture in the bismuth-removing raw material contacts and eutectics to form a network skeleton, and at the same time, the calcium compound and the slag material constitute entrained components, and the entrained components are dispersed in the skeleton to form a bismuth-removing layer 11;

[0060] Step 3: consolidation of the silver removal layer: spray a sintering layer containing a silver removal raw material on the bismuth layer 11 and sinter with oxygen isolation. The silver removal raw material sprinkled from the feeding tube falls on the surface of the substrate 10 to form a sintering layer. The sintering temperature is 400° C. to 420° C. The metal mixture in the silver removal raw material contacts and eutectics to form a mesh skeleton. At the same time, the slag material forms an entrained component, which is dispersed in the skeleton to form a silver removal layer 12.

[0061] The specific thickness of the bismuth removal layer 11 and the silver removal layer 12 is adjusted according to the impurity content and the target content in the crude lead;

[0062] Step 4: After the bismuth removal layer 11 and the silver removal layer 12 are cooled to room temperature, the lead smelting bismuth removal and silver removal agent is obtained.

[0063] The metals or metal compounds that play a major role in the above-mentioned bismuth removal raw materials and silver removal raw materials are all prior art. K. Mallaley et al.'s "Analysis of the Betterton-Kroll Process: Removal of Bismuth from Crude Lead", JRMRHTA AHLARSON's "Removal of Silver from Low-Silver Crude Lead", Dian-kun LU et al.'s "Mechanism of debismuthizing with calcium and magnesium" and the like have disclosed their bismuth removal and silver removal mechanisms and methods for calculating the amount of addition. Therefore, the weight, thickness and other production parameters required for the bismuth removal layer and the silver removal layer of the present invention can be calculated from the weight of the required bismuth removal raw materials and the silver removal raw materials, the outer diameter of the substrate and other parameters. The present invention is more about improving the lead smelting effect with special components and different addition methods as the research object.

[0064] A production equipment for removing bismuth and silver from lead smelting, used for producing the bismuth and silver from lead smelting, such as Figure 1 As shown, the lead smelting bismuth and silver removal agent is a solid spherical preparation, and the lead smelting bismuth and silver removal agent includes a substrate 10, a bismuth removal layer 11 and a silver removal layer 12 from the inside to the outside. Figure 2 and Figure 3 As shown, the production equipment includes a shell 1, a feeding part 2, a heating part 3 and a support roller group 4. The shell 1 has a connecting pipe 5 for vacuuming. The shell 1 has a support roller group 4. The support roller group 4 is composed of three support rollers. The three support rollers make the substrate 10 produce horizontal rotation during the rolling process in the vertical direction. Two of the three support rollers produce a vertical rolling effect on the substrate 10, and the other support roller not only produces a vertical rolling effect on the substrate 10 but also makes the substrate 10 produce a rotation tendency in the horizontal direction, as shown in FIG. Figure 4As shown, three support rollers are driven by three motors through the rotating shaft that penetrates the shell 1. Two of the three support rollers are in the vertical direction (the rotating shaft is horizontal), and the other support roller is in the inclined direction (the rotating shaft is inclined), and the rotation speed is higher than that of the other two support rollers. The feeding part 2 is located outside the shell 1. The feeding part 2 includes two storage bins 6, a screw conveyor 7 and a feeding pipe 8. The two storage bins 6 are storage spaces with a accommodating cavity. The top of the storage bin 6 is provided with a cover 9. The two ends of the screw conveyor 7 are respectively connected to the two storage bins 6, and the middle of the screw conveyor 7 is connected to the feeding pipe 8. The feeding part 2 is used to sprinkle the raw materials of the bismuth layer 11 onto the surface of the substrate 10 by the feeding pipe 8. The raw material of the silver layer 12 is sprinkled onto the surface of the bismuth removal layer 11. When the screw conveyor 7 rotates forward, the raw material of the bismuth removal layer 11 is conveyed into the feeding tube 8. When the screw conveyor 7 rotates reversely, the raw material of the silver removal layer 12 is conveyed into the feeding tube 8. The feeding tube 8 is a double-layer or multi-layer tubular body extending into the shell 1. The double-layer or multi-layer tubular body can effectively isolate the temperature and prevent the raw material from adhering to the feeding tube 8. The heating method of the heating part 3 is radiation heating. The heating part 3 is inclined toward the projection area of ​​the feeding tube 8 on the surface of the substrate 10. A reflective cover is provided on the heating part 3. The reflective cover makes the radiation area of ​​the heating part 3 concentrated on the upward ball of the substrate 10, and the radiation area wraps the projection of the feeding tube 8 on the surface of the substrate 10.

[0065] The present invention uses silicon carbide as a heating element for radiation heating, and sets a temperature probe facing the substrate on the outer wall of the feeding tube 8. As the substrate rolls, the bismuth-removing raw material in the feeding tube 8 falls onto the substrate 10 to form a material strip with a thickness of 0.5 mm to 1 mm. Figure 5 As shown in the figure, the contour i is the radiation area of ​​the heating part 3, the contour j is the projection area of ​​the feeding pipe 8, and the rotation direction of the substrate 10 is as shown in Figure 5In the direction marked on the middle substrate 10, the material strip can remain in the radiation area for a relatively long time. The time from the beginning of radiation heating to the eutectic melting of the bismuth-removing raw material and bonding with the substrate is 15 seconds. The surface temperature of the bismuth-removing raw material is 580°C~620°C, and the average temperature is 600°C, which is basically close to the melting point of the alloy. When the substrate continues to roll, the raw material is transferred out of the radiation area and no longer receives radiation. The temperature drops rapidly, and the eutectic area solidifies rapidly to form a skeleton. When the substrate rolls, the bismuth-removing raw material in the feeding tube 8 continues to fall onto the substrate 10. The multi-layer material strip formed on the surface of the substrate 10 forms a bismuth-removing layer 11. When the mass of the bismuth-removing layer 11 reaches When required (calculated based on the quality of the lead liquid and the bismuth content), stop the rotation of the screw conveyor 7, and stop making the bismuth removal layer 11. Then, reduce the heating power of the heating unit 3 so that the heating temperature of the bismuth removal layer 11 by the heating unit 3 is maintained at 400°C ~ 420°C, and then reverse the screw conveyor 7. At this time, the feeding pipe 8 scatters the raw materials of the silver removal layer 12 onto the surface of the bismuth removal layer 11. The raw materials of the silver removal layer 12 are also radiation sintered to form a material belt of the silver removal layer 12. When making the silver removal layer, the method is the same as the method for making the bismuth removal layer, except that the radiation power of the heating unit 3 is lower than the radiation power when making the bismuth removal layer or the rotation speed of the substrate is accelerated.

[0066] In the sintering process of the present invention, since radiation heating is used, the material is in powder or granular form, the heat conduction and reflection are small, the temperature rises quickly after radiation, and the temperature can be quickly raised to produce eutectic.

[0067] The lead smelting bismuth and silver removal agent of the present invention is produced by using the above-mentioned lead smelting bismuth and silver removal agent production equipment, the bismuth removal layer 11 wraps the substrate 10 and the oxygen-isolating sintering is carried out simultaneously, and the silver removal layer 12 wraps the bismuth removal layer 11 and the oxygen-isolating sintering is carried out simultaneously, that is, the substrate 10 produces horizontal rotation during the rolling process in the vertical direction, and the raw materials of the bismuth removal layer 11 are scattered from a fixed position to the surface of the substrate 10. The scattered raw materials are subjected to radiation heating when falling on the surface of the substrate 10, and the metal parts in the raw materials contact each other to produce a eutectic region, forming a mesh skeleton, which will melt the high-melting The point part is wrapped and entrained inside, and as the substrate 10 rolls, the sintered part turns out of the radiation area for cooling, and a sintered belt composed of bismuth-removing raw materials is formed on the surface of the substrate 10. As the number of rotations of the substrate 10 increases, the sintered belt forms a spherical shell-shaped sintered layer outside the substrate, constituting a bismuth-removing layer, and the thickness becomes thicker and thicker. After the weight of the bismuth-removing layer 11 reaches the requirement, the raw materials of the silver-removing layer 12 are scattered and sintered outside the bismuth-removing layer 11, and the above process is repeated to form the silver-removing layer 12. When the silver-removing layer 12 reaches a certain thickness, the production of the bismuth-removing and silver-removing agent for lead smelting is completed.

[0068] If the production equipment of the bismuth and silver removal agent for lead smelting of the present invention is not used, the bismuth removal raw material and the silver removal raw material can also be mixed into a colloid by using an organic adhesive, and then sprayed on the substrate in sequence, and placed in a Ma furnace for oxygen isolation sintering. However, this method requires two coatings and two sinterings, with a long process time and high cost. It is better to use the production equipment of the bismuth and silver removal agent for lead smelting of the present invention, which has a simple process, fast production speed and low cost.

[0069] The lead smelting bismuth and silver removal agent of the present invention is used for refining crude lead after copper, arsenic, antimony and tin are removed. An immersion cage is used to control the bismuth and silver removal agent spheres in the lower part of the lead liquid. The lead liquid is first heated to 380°C to 400°C, at which time the silver removal layer begins to dissolve. Increasing the temperature will accelerate the dissolution rate. When the silver removal layer dissolves, the mark at this time is that there is no slag floating for a long time at 380°C to 400°C and the surface of the lead liquid tends to be stable, indicating that the silver removal layer dissolves. At this time, the lead liquid temperature is reduced to 330°C to 400°C. 350℃, clarification for 10 minutes and then slag is removed, the removed slag is used to recover silver, after the slag removal is completed, the lead liquid temperature is raised to 540℃~550℃, at this time, the dissolution of the bismuth removal layer is accelerated, and bismuth removal begins. When the dissolution of the bismuth removal layer is completed, the above-mentioned signs also appear, and the performance is very obvious. At this time, the lead liquid temperature is lowered to 330℃~350℃, clarification for 10 minutes and then slag is removed to obtain slag with higher bismuth content. In the bismuth removal stage, the lead liquid temperature is repeatedly lowered to below 400℃, and multiple intermediate slag removals will make the bismuth removal effect better.

[0070] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for producing a bismuth-removing and silver-removing agent for lead smelting, characterized in that: The lead smelting bismuth and silver removal agent is a solid spherical preparation, which is based on the outer surface of a substrate (10) and is composed of a bismuth removal layer (11) and a silver removal layer (12) sequentially solidified; the bismuth removal layer (11) and the silver removal layer (12) both contain a metal mixture and a slag reduction material; the bismuth removal layer (11) also contains a calcium compound; The production method of the lead smelting bismuth and silver removal agent comprises the following specific steps: Step 1: preparing materials: weighing a bismuth-removing raw material and a silver-removing raw material as needed and mixing them separately, wherein the bismuth-removing raw material and the silver-removing raw material are both ground into 100-200 meshes; Step 2: Consolidation of the bismuth-removing layer: preparing a substrate (10), spraying a sintering layer containing a bismuth-removing raw material on the outside of the substrate (10), and sintering the layer in an oxygen-insulated state, wherein the sintering temperature is 580° C. to 620° C.; wherein the metal mixture in the bismuth-removing raw material comes into contact and eutectics to form a network skeleton, and at the same time, the calcium compound and the slag material constitute entrained components, and the entrained components are dispersed in the skeleton to form a bismuth-removing layer (11); Step 3: consolidation of the desilvering layer: spraying a sintering layer containing a desilvering raw material on the bismuth layer (11) and sintering in an oxygen-insulated manner, the sintering temperature being 400° C. to 420° C., the metal mixture in the desilvering raw material comes into contact and eutectics to form a network skeleton, while the slag material forms an entrained component, and the entrained component is dispersed in the skeleton to form a desilvering layer (12); Step 4: After the bismuth removal layer (11) and the silver removal layer (12) are cooled to room temperature, a lead smelting bismuth removal and silver removal agent is obtained; The matrix (10) is a sphere that is insoluble in lead liquid and does not react with the lead liquid.

2. The method for producing a bismuth-removing and silver-removing agent for lead smelting according to claim 1, characterized in that: The substrate (10) is a sphere made of stainless steel or alumina ceramics.

3. The method for producing a bismuth-removing and silver-removing agent for lead smelting according to claim 1, characterized in that: The metal mixture in the bismuth removal raw material includes aluminum powder, metal magnesium particles, metal calcium particles, and metal antimony particles, the calcium compound includes calcium chloride powder and calcium carbide powder, and the slag reduction material includes fluorite powder and pseudo-boehmite. The components are arranged in descending order by volume as follows: aluminum powder, metal magnesium particles, metal calcium particles, metal antimony particles, calcium chloride powder, calcium carbide powder, fluorite powder, and pseudo-boehmite, and the sum of the volumes of the aluminum powder, metal magnesium particles, and metal calcium particles accounts for 60% to 80% of the total volume of the raw material for the bismuth removal layer (11).

4. The method for producing a bismuth-removing and silver-removing agent for lead smelting according to claim 1, characterized in that: The metal mixture in the desilvering raw material includes zinc powder and aluminum powder, and the slag-reducing material includes fluorite powder and pseudo-boehmite. The components are arranged in descending order by volume as follows: zinc powder, aluminum powder, fluorite powder, pseudo-boehmite, and the total volume of the zinc powder and the aluminum powder accounts for 60% to 80% of the total volume of the desilvering layer (12) raw material.

5. The method for producing a bismuth-removing and silver-removing agent for lead smelting according to claim 1, characterized in that: The heating method of the oxygen-insulating sintering is radiation heating.

6. A production device for removing bismuth and silver from lead smelting, which realizes the production method for removing bismuth and silver from lead smelting according to any one of claims 1 to 5, characterized in that: The invention comprises a shell (1), a feeding part (2), a heating part (3) and a supporting roller group (4), wherein the shell (1) has a connecting pipe (5) for vacuuming, the shell (1) has a supporting roller group (4), the supporting roller group (4) is composed of three supporting rollers, and the three supporting rollers enable the substrate (10) to generate horizontal rotation during the rolling process in the vertical direction, the feeding part (2) is located outside the shell (1) and has a feeding pipe (8) extending into the shell (1), the feeding part (2) sprinkles raw materials for removing bismuth layer (11) onto the surface of the substrate (10) and sprinkles raw materials for removing silver layer (12) onto the surface of the bismuth layer (11) through the feeding pipe (8), the heating method of the heating part (3) is radiation heating, and the heating part (3) is inclined toward the projection area of ​​the feeding pipe (8) on the surface of the substrate (10).

7. The production equipment for removing bismuth and silver from lead smelting according to claim 6, characterized in that: Two of the three support rollers produce a rolling effect on the base body (10) in the vertical direction, and the other support roller, in addition to producing a rolling effect on the base body (10) in the vertical direction, also causes the base body (10) to produce a tendency to rotate in the horizontal direction.

8. The production equipment for removing bismuth and silver from lead smelting according to claim 6, characterized in that: The feeding part (2) comprises two storage bins (6), a screw conveyor (7) and a feeding pipe (8), the two storage bins (6) are storage spaces with a containing cavity, the top of each storage bin (6) is provided with a sealing cover (9), the screw conveyor (7) is connected to the two storage bins (6), the middle of the screw conveyor (7) is connected to the feeding pipe (8), and the feeding pipe (8) is a double-layer or multi-layer tubular body.

9. The production equipment for removing bismuth and silver from lead smelting according to claim 6, characterized in that: The heating portion (3) is provided with a reflective cover, which concentrates the radiation area of ​​the heating portion (3) on the surface of the substrate (10), and the radiation area wraps around the projection of the feeding tube (8) on the surface of the substrate (10).

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