A method for reducing smelting of low-sulfur and high-zinc oxide

Abstract

The present application provides a method for reducing and smelting low-sulfur high-zinc oxide. The low-sulfur high-zinc oxide is preliminarily reduced with a first reducing agent in a first reduction zone to obtain preliminarily reduced material. The preliminarily reduced material is subjected to a deep reduction reaction with oxygen-rich gas introduced through jet injection and a carbonaceous reducing agent in a second reduction zone to obtain an iron-containing metal material and zinc-containing vapor. The zinc-containing vapor is condensed to produce crude zinc liquid. The crude zinc liquid is rectified to obtain refined zinc. Among them, the volume ratio of CO to CO2 in the first reduction zone and the second reduction zone is 20-35:1. In the present application, through preliminary reduction and deep reduction, the low-sulfur high-zinc oxide is completely reduced and recovered into the iron-containing metal material, and at the same time, the reduction rate of zinc metal is greatly improved, having good social benefits and production economic benefits.

Description

Technical Field

[0001] This application relates to the field of metal reduction and recycling, and particularly to a reduction smelting method for low-sulfur and high-zinc oxides. Background Art

[0002] Pyrometallurgical zinc smelting has the characteristics of processing complex raw materials and simple process, and has been widely applied in the smelting of lead and zinc metals. Among them, the pyrometallurgical processes mainly include blast furnace, shaft furnace and electric furnace processes, and their processes all include the oxidation, reduction of zinc sulfide materials and the comprehensive recovery of crude zinc rectification, etc.

[0003] Currently, in the reduction stage of zinc-containing oxides, the zinc-containing oxides are added to a reduction furnace, pulverized coal is sprayed into the reduction furnace or natural gas is introduced into the reduction furnace, and at the same time oxygen is introduced and the temperature in the reduction furnace is controlled for reduction smelting. However, the form of adding the reducing agent in the reduction process is single, resulting in incomplete reduction of low-sulfur and high-zinc oxides, and it is difficult to recover other valuable metals therein, especially iron metal. Summary of the Invention

[0004] This application aims to solve at least one of the technical problems in the related art to some extent. This application provides a reduction smelting method for low-sulfur and high-zinc oxides. The low-sulfur and high-zinc oxides are preliminarily reduced and deeply reduced, and the volume ratio of CO to CO2 in the reduction process is controlled to be 20 - 35:1, so as to achieve complete reduction of the low-sulfur and high-zinc oxides and recover iron-containing metal materials. At the same time, the reduction rate of zinc metal is greatly increased, and it has good social benefits and production economic benefits.

[0005] According to an embodiment of this application, a reduction smelting method for low-sulfur and high-zinc oxides is provided, including the following steps:

[0006] The low-sulfur and high-zinc oxides and a first reducing agent are subjected to preliminary reduction in a first reduction zone to obtain preliminarily reduced materials;

[0007] The preliminarily reduced materials are subjected to a deep reduction reaction in a second reduction zone with oxygen-rich gas and a carbonaceous reducing agent introduced by jet injection to obtain iron-containing metal materials and zinc-containing vapor; the zinc-containing vapor is condensed to produce crude zinc liquid; the crude zinc liquid is rectified to obtain refined zinc;

[0008] Wherein the volume ratio of CO to CO2 in the first reduction zone and the second reduction zone is 20 - 35:1.

[0009] In some embodiments, based on the low-sulfur and high-zinc oxides, by mass percentage, the sulfur element content in the low-sulfur and high-zinc oxides is ≤1%, and the Zn element content is ≥25%;

[0010] And / or, the first reduction zone is electrically heated and reduced, and electrode heat supplement is adopted; the reduction smelting temperature is 1200-1300°C

[0011] And / or, the first reducing agent includes at least one of coke lumps, crushed coke, and anthracite lumps; it is added from the charging port of the first reduction zone;

[0012] And / or, the molar ratio of carbon element in the first reducing agent to zinc element in the low-sulfur high-zinc oxide is 0.8-1.2:1.

[0013] In some embodiments, the second reduction zone is jet injection combustion reduction; the reduction smelting temperature is 1350-1500°C;

[0014] And / or, the carbonaceous reducing agent includes coke powder and / or coal powder; the molar ratio of carbon element in the carbonaceous reducing agent to zinc element in the low-sulfur high-zinc oxide is 0.2-0.5:1;

[0015] And / or, the injection amount of the oxygen-rich gas is 0.1-0.5 of the total volume of oxygen required for complete combustion of the carbonaceous reducing agent in the second reduction zone;

[0016] And / or, the oxygen concentration of the oxygen-rich gas is 23-99.8%, and the pressure is 0.2-0.5 MPa.

[0017] In some embodiments, the time for the preliminary reduction and deep reduction reactions of the low-sulfur high-zinc oxide is 2-6 h per furnace;

[0018] And / or, the time for the preliminary reduction of the low-sulfur high-zinc oxide is 1-3 h per furnace;

[0019] And / or, the time for the deep reduction reaction of the preliminarily reduced material is 1-3 h per furnace.

[0020] In some embodiments, the heat supplement ratio of the first reduction zone to the second reduction zone is 2-5:1.

[0021] In some embodiments, the iron-containing metal material includes pig iron as well as copper metal, gold metal, and silver metal.

[0022] In some embodiments, during the rectification of the crude zinc liquid, the vapor temperature is first controlled at 900-950°C to separate and recover lead metal; then the vapor temperature is controlled at 500-600°C to obtain refined zinc while enriching cadmium metal, indium metal, and germanium metal into hard zinc.

[0023] In some embodiments, the recovery rate of zinc in the low-sulfur high-zinc oxide is 97%-98%, the recovery rate of lead is 97%-98%, the recovery rate of copper is 90%-95%, the recovery rate of cadmium is 90%-95%, the recovery rate of gold is 90%-95%, the recovery rate of silver is 90%-95%, the recovery rate of indium is 90%-95%, and the recovery rate of germanium is 90%-95%.

[0024] In some embodiments, the purity of the refined zinc > 99.995%.

[0025] The low-sulfur high-zinc oxide of the present application undergoes preliminary reduction and deep reduction, and high-temperature reduction is achieved by controlling the volume ratio of CO to CO2 during the reduction process to be 20-35:1, producing iron-containing metal materials and zinc vapor. Among them, copper, gold, and silver elements are also enriched in the iron-containing metal materials and recovered; the zinc element in the low-sulfur high-zinc oxide is reduced to form zinc vapor. Among them, valuable metals such as cadmium, lead, indium, and germanium in the low-sulfur high-zinc oxide volatilize into the zinc vapor and are discharged from the flue gas outlet of the second reduction zone. The zinc vapor is condensed by a zinc vapor condensation device to produce crude zinc liquid; the crude zinc liquid is rectified to obtain refined zinc. The present application realizes the complete reduction of the low-sulfur high-zinc oxide and recovers the iron-containing metal materials. At the same time, the overflow rate of zinc metal is greatly increased, with good social and production economic benefits.

[0026] Additional aspects and advantages of the present application will be given in part in the following description, will become apparent in part from the following description, or will be understood through the practice of the present application. Description of the Drawings

[0027] The above-mentioned and / or additional aspects and advantages of the present application will become apparent and easy to understand from the following description of the embodiments in conjunction with the drawings, where:

[0028] Figure 1 is a process flow chart of the reduction smelting of low-sulfur high-zinc oxide according to an embodiment of the present application. Detailed Embodiments

[0029] The embodiments of the present application will be described in detail below. The examples of the embodiments are shown in the drawings, where the same or similar reference numerals denote the same or similar elements or elements with the same or similar functions from beginning to end. The embodiments described below with reference to the drawings are exemplary only for explaining the present application and should not be construed as limiting the present application. On the contrary, the present application includes all changes, modifications, and equivalents falling within the spirit and scope of the appended claims.

[0030] The existing hydrometallurgical zinc smelting technology has a long process flow, complex processes, huge investment, and relatively high energy consumption. Most importantly, a large amount of leaching residues, iron slag, etc. are generated during the hydrometallurgical process, and their output rate exceeds 50%. All of them are hazardous wastes and need to be treated harmlessly, which causes a large amount of energy consumption and brings new pollution. The existing pyrometallurgical zinc smelting technology generally has high energy consumption, a complex batching process, low direct zinc recovery rate and recovery rate, small single-series production capacity, and cannot meet the requirements of modern large-scale industrial production.

[0031] In the current related technologies, a lead-zinc ore smelting method is mentioned. The lead-zinc ore is melted in an oxidative smelting furnace, and the melt is sent to a power frequency electric heating reduction furnace for reduction. Zinc vapor is condensed by traditional lead rain or zinc rain to obtain crude zinc; or zinc sulfide materials are melted in an oxygen bottom-blown smelting furnace, and the melt is sent to a side-blown reduction furnace for reduction. Zinc vapor is condensed by traditional lead rain or zinc rain to obtain crude zinc; zinc sulfide materials are melted in an oxygen bottom-blown smelting furnace, and then cast into blocks and sent to a blast furnace for reduction. Zinc vapor is condensed by traditional lead rain or zinc rain to obtain crude zinc. The above methods have solved many problems existing in hydrometallurgical zinc smelting, but compared with the existing pyrometallurgical zinc smelting methods, only the problem of complex batching systems has been mainly solved, and there is no obvious improvement in the smelting process and the recovery of valuable metals.

[0032] To solve the problem of low recovery rate of valuable metals, some related technologies mention using a blast furnace for smelting. The molten slag needs to be cast and cooled, the batching process is complex, the energy consumption is high, the zinc recovery rate has not increased compared with the traditional pyrometallurgical zinc smelting technology, and there is room for further improvement in the recovery rate of valuable metal recovery. There are also some related technologies that mention using two metallurgical furnaces. The molten slag flows from the bottom-blown furnace into the side-blown furnace, inevitably resulting in heat loss and increasing the flue gas escape points. The side-blown furnace reduction belongs to bath smelting, and a large amount of oxygen-rich air needs to be blown in, resulting in a low concentration of zinc vapor, which is more likely to cause secondary oxidation of zinc vapor and reduce the direct zinc recovery rate. The smelting temperature of the side-blown furnace is 1200 - 1250 °C, the zinc content in the slag is relatively high, the direct zinc recovery rate and recovery rate are low, iron cannot be recovered, and the subsequent flue gas treatment cost is high. There is room for further improvement in the recovery rate of valuable metal recovery. In addition, some related technologies mention using two metallurgical furnaces. The molten slag flows from the oxidative smelting furnace into the power frequency electric heating reduction furnace, inevitably resulting in heat loss and increasing the flue gas escape points. The smelting temperature of the power frequency electric heating reduction furnace is limited, which will cause a relatively high zinc content in the slag, low zinc recovery rate, and iron cannot be recovered. The single-series production capacity of the power frequency electric heating reduction furnace is limited, making it difficult to adapt to large-scale industrial production, and there is room for further improvement in the recovery rate of valuable metal recovery.

[0033] Based on this, the technical solution of the embodiment of the present application provides a reduction smelting method for low-sulfur high-zinc oxides, which realizes the complete reduction of low-sulfur high-zinc oxides and recovers them into iron-containing metal materials, while greatly improving the reduction rate of zinc metal, and has good social benefits and production economic benefits.

[0034] The "range" disclosed in this application is defined in the form of a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundaries of a particular range. The ranges defined in this way can include the end values or not include the end values, and can be combined arbitrarily, that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60 - 120 and 80 - 110 are listed for a specific parameter, ranges of 60 - 110 and 80 - 120 are also contemplated. In addition, if the minimum range values 1 and 2 are listed, and if the maximum range values 3, 4, and 5 are listed, then the following ranges are all contemplated: 1 - 3, 1 - 4, 1 - 5, 2 - 3, 2 - 4, and 2 - 5. In this application, unless otherwise stated, the numerical range "a - b" represents an abbreviated representation of any real number combination between a and b, where both a and b are real numbers. For example, the numerical range "0 - 5" means that all real numbers between "0 - 5" are fully listed herein, and "0 - 5" is only an abbreviated representation of these numerical combinations. Additionally, when stating that a certain parameter is an integer ≥ 2, it is equivalent to disclosing that the parameter is, for example, the integers 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0035] In the description of the embodiments of this application, the term "and / or" is merely a description of the association relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. Additionally, in this article, the character " / " generally indicates that the associated objects before and after are in an "or" relationship.

[0036] To achieve the above object, according to an embodiment of this application, a reduction smelting method for low - sulfur high - zinc oxide is proposed as Figure 1 , including the following steps:

[0037] S1: The low - sulfur high - zinc oxide is preliminarily reduced with a first reducing agent in a first reduction zone to obtain preliminarily reduced materials;

[0038] S2: The preliminarily reduced materials are subjected to a deep reduction reaction with oxygen - rich gas injected through jet injection and a carbonaceous reducing agent in a second reduction zone to obtain iron - containing metal materials and zinc - containing vapor; the zinc - containing vapor is condensed to produce crude zinc liquid; the crude zinc liquid is rectified to obtain refined zinc;

[0039] Wherein the volume ratio of CO to CO2 in the first reduction zone and the second reduction zone is 20 - 35:1.

[0040] Among them, in S1, based on the low-sulfur and high-zinc oxide, the sulfur element content is ≤1% and the Zn element content is ≥25% by mass percentage. It can be the product formed after the zinc sulfide material is oxidized. The zinc sulfide material includes zinc, lead, and sulfur elements, and usually also includes iron, sulfur, calcium, and silicon elements. In addition to the above elements, in some embodiments, the lead-zinc sulfide material may also include other elements, such as oxygen, magnesium, copper, aluminum, cadmium, arsenic, etc. Compared with other elements, the contents of zinc, lead, iron, sulfur, calcium, and silicon elements are relatively high. Exemplarily, based on the lead-zinc sulfide material, by weight percentage, the lead-zinc sulfide material includes Zn 10-40 wt.%; Pb 5-30 wt.%; S 10-30 wt.%; Fe 3-15 wt.%; Ca 1-10 wt.%; SiO2 2-10 wt.%. For example, Zn 20-40 wt.%, Pb 10-30 wt.%, S 15-30 wt.%, Fe 4-15 wt.%, Ca 1-5 wt.%, SiO2 2-6 wt.%. The lead-zinc sulfide material can be natural lead-zinc sulfide minerals or raw materials formed by smelting with relatively high contents of sulfur, lead, and zinc elements. Among them, according to the different elements with the highest content, the lead-zinc sulfide material can be divided into lead concentrate (the highest lead content) and zinc concentrate (the highest zinc content).

[0041] Exemplarily, the main elements and their component contents of the lead concentrate are Pb 36.82 wt.%, Zn 16.25 wt.%, S 13.86 wt.%, Fe 3.84 wt.%, Cu 0.40 wt.%, CaO 3.08 wt.%, SiO2 5.16 wt.%.

[0042] Exemplarily, the main elements and their component contents of the zinc concentrate are Zn 43.49 wt.%, Pb 3.09 wt.%, S 28.61 wt.%, Fe 11.10 wt.%, Cu 0.74 wt.%, Cd 0.39 wt.%, CaO 0.82 wt.%, SiO2 6.12 wt.%.

[0043] As can be seen from the above, the low-sulfur and high-zinc oxide also contains various recyclable metals such as cadmium, lead, indium, germanium, iron, copper, gold, and silver. The low-sulfur and high-zinc oxide is added to the first reduction zone. The first reducing agent includes at least one of coke lumps, crushed coke, and anthracite lumps and is added through the feeding port of the first reduction zone. The low-sulfur and high-zinc oxide and the first reducing agent are preliminarily reduced in the first reduction zone to obtain preliminarily reduced materials.

[0044] Exemplarily, the molar ratio of carbon element in the first reducing agent to zinc element in the low-sulfur high-zinc oxide is 0.8 - 1.2:1. Exemplarily, the molar ratio of carbon element in the first reducing agent to zinc element in the low-sulfur high-zinc oxide is (0.8, 0.9, 1.0, 1.1, 1.2):1. When the molar ratio of carbon element in the first reducing agent to zinc element in the low-sulfur high-zinc oxide is relatively small, such as less than 0.8, the zinc content in the reduction slag is too high, and the mass percentage of zinc element therein > 5%, resulting in a decrease in the direct recovery rate of zinc; when the molar ratio of carbon element in the first reducing agent to zinc element in the low-sulfur high-zinc oxide is relatively large, such as greater than 1.2, the surplus of the first reducing agent is too large, increasing the production cost.

[0045] Among them, the first reduction zone is electrically heated for reduction, and it adopts the method of electrode heat supplement. The reduction smelting temperature is 1200 - 1300 °C; Exemplarily, the reduction smelting temperatures of the first reduction zone are 1200 °C, 1230 °C, 1250 °C, and 1300 °C, etc. The time for the preliminary reduction of the low-sulfur high-zinc oxide is 1 - 3 h per furnace; Exemplarily, the time for the preliminary reduction of the low-sulfur high-zinc oxide is 1 h per furnace, 2 h per furnace, or 3 h per furnace, etc. When the reduction smelting temperature of the low-sulfur high-zinc oxide in the first reduction zone is relatively low, such as lower than 1200 °C and the time is short, the zinc content in the slag is too high, the zinc content in the slag > 5%, and the direct recovery rate of zinc decreases; when the reduction smelting temperature of the low-sulfur high-zinc oxide in the first reduction zone is relatively high, such as higher than 1300 °C and the time is long, it will increase the energy consumption of zinc smelting and increase the production cost.

[0046] In addition, during this process, the volume ratio of CO to CO2 in the first reduction zone is controlled to be 20 - 35:1. For example, the volume ratio of CO to CO2 in the first reduction zone is (20, 21, 24, 25, 26, 28, 29, 30, 31, 32, 23, 24, 35):1, etc. Among them, when the volume ratio of CO to CO2 in the first reduction zone is relatively small, such as less than 20, a large amount of metal zinc vapor will be oxidized to zinc oxide by CO2 in the flue gas, reducing the direct recovery rate of zinc; when the volume ratio of CO to CO2 in the first reduction zone is relatively large, such as greater than 35, the surplus of the reducing agent is too large, increasing the production cost.

[0047] Among them, in S2, the preliminary reduction material obtained in S1 is subjected to a deep reduction reaction with an oxygen-rich gas and a carbonaceous reducing agent in the second reduction zone. The oxygen concentration of the oxygen-rich gas is 23 - 99.8%, the pressure is 0.2 - 0.5 MPa, and the carbonaceous reducing agent is coke powder and / or pulverized coal; the oxygen-rich gas and the carbonaceous reducing agent enter the second reduction zone by means of injection, and the injection amount of the oxygen-rich gas is 0.1 - 0.5 of the total volume of oxygen required for the complete combustion of the carbonaceous reducing agent. Exemplarily, the injection amount of the oxygen-rich gas is 0.1, 0.2, 0.3, 0.4, 0.5, etc. of the total volume of oxygen required for the complete combustion of the carbonaceous reducing agent.

[0048] The injection amount of the carbonaceous reducing agent is such that the molar ratio of the carbon element in the carbonaceous reducing agent to the zinc element in the low-sulfur high-zinc oxide is 0.2 - 0.5:1. In the example, the molar ratio of the carbon element in the carbonaceous reducing agent to the zinc element in the low-sulfur high-zinc oxide is (0.2, 0.3, 0.4, 0.5):1. When the molar ratio of the carbon element in the carbonaceous reducing agent to the zinc element in the low-sulfur high-zinc oxide is relatively small, such as less than 0.2, the reducing agent is insufficient. The second reduction zone is mainly used to reduce the iron element in the slag to produce pig iron. Insufficient reducing agent results in the inability to reduce pig iron or only a small amount of reduction, and it is mixed in the slag and cannot be separated from the slag, making it impossible to further recover precious metals such as gold and silver. When the molar ratio of the carbon element in the carbonaceous reducing agent to the zinc element in the low-sulfur high-zinc oxide is relatively large, such as greater than 0.5, the surplus of the reducing agent is too large, increasing the production cost.

[0049] In this embodiment, the oxygen-rich gas and the carbonaceous reducing agent enter the second reduction zone by jet injection. The injection method in the second reduction zone includes single side blowing, single bottom blowing, or a combination of side blowing and bottom blowing. On the one hand, it provides heat for deep reduction, and on the other hand, it provides a carbonaceous reducing agent for the reduction process. The continuous injection of the carbonaceous reducing agent ensures that the volume ratio of CO to CO2 in the second reduction zone is 20 - 35:1, enabling the low-sulfur high-zinc oxide to undergo a deep reduction reaction to obtain iron-containing metal materials and zinc vapor, significantly increasing the overflow rate of zinc metal.

[0050] The reduction smelting temperature in the second reduction zone is 1350 - 1500 °C. In the example, the reduction smelting temperatures in the second reduction zone are 1350 °C, 1400 °C, 1450 °C, and 1500 °C, etc. The time for the preliminary reduction material to undergo a deep reduction reaction is 1 - 3 h per furnace charge. In the example, the times for the preliminary reduction material to undergo a deep reduction reaction are 1 h per furnace charge, 2 h per furnace charge, or 3 h per furnace charge, etc. When the reduction smelting temperature of the preliminary reduction material in the second reduction zone is relatively low, such as lower than 1350 °C and the time is short, the power during the reduction process is insufficient, resulting in difficulty in reducing pig iron or only a small amount of reduction and being mixed in the slag, unable to be separated from the slag, and unable to further recover precious metals such as gold and silver. When the reduction smelting temperature of the preliminary reduction material in the second reduction zone is relatively high, such as higher than 1500 °C and the time is long, the smelting energy consumption will increase, increasing the production cost.

[0051] During this process, the volume ratio of CO to CO2 in the second reduction zone is (20, 21, 24, 25, 26, 28, 29, 30, 31, 32, 23, 24, 35):1, etc. Among them, when the volume ratio of CO to CO2 in the second reduction zone is small, such as less than 20, the reduction degree is insufficient, resulting in difficult reduction of pig iron or very little reduction and being mixed in the slag, unable to be separated from the slag and unable to further recover precious metals such as gold and silver; when the volume ratio of CO to CO2 in the second reduction zone is large, such as greater than 35, the surplus of the reducing agent is too large, increasing the production cost.

[0052] In some embodiments, the heat supplement ratio of the first reduction zone to the second reduction zone is 2-5:1.

[0053] Among them, the heat supplement ratio of the first reduction zone to the second reduction zone is (2, 3, 4, 5):1, etc., and (the beneficial effects of this heat supplement ratio need to be further described). Among them, the time for ensuring the preliminary reduction and deep reduction reactions of low-sulfur and high-zinc oxides is 2-6 h per furnace.

[0054] The low-sulfur and high-zinc oxides are subjected to high-temperature reduction in the first reduction zone and the second reduction zone to obtain iron-containing metal materials and zinc-containing vapors. The iron-containing metal materials include pig iron and copper metal, gold metal, and silver metal. The valuable metals such as copper metal, gold metal, and silver metal are recovered from the pig iron; the zinc-containing vapors include zinc vapor and lead, cadmium, and indium, germanium reduced to form vapors and enter the zinc vapor condensation device together for trapping and condensation to form crude zinc liquid. The crude zinc liquid passes through the crude zinc rectification system. First, the vapor temperature is controlled at 900-950 °C to separate and recover lead metal; then the vapor temperature is controlled at 500-600 °C to obtain refined zinc while enriching cadmium metal, indium metal, and germanium metal to hard zinc, achieving the purpose of recovering valuable metals such as cadmium metal, indium metal, and germanium metal, and at the same time producing refined zinc with a purity > 99.995%.

[0055] According to the reduction smelting method of low-sulfur and high-zinc oxides of the present application, the recovery rate of zinc in the low-sulfur and high-zinc oxides is 97%-98%, the recovery rate of lead is 97%-98%, the recovery rate of copper is 90%-95%, the recovery rate of cadmium is 90%-95%, the recovery rate of gold is 90%-95%, the recovery rate of silver is 90%-95%, the recovery rate of indium is 90%-95%, and the recovery rate of germanium is 90%-95%.

[0056] To facilitate further understanding of the present application, the following further describes the solution of the present application with reference to embodiments. Those skilled in the art will understand that only some examples are described in the present application, and any other suitable specific examples are within the scope of the present application.

[0057] Example 1

[0058] This embodiment provides a reduction smelting method for low-sulfur and high-zinc oxides. The product obtained by smelting and oxidizing zinc concentrate is used as the low-sulfur and high-zinc oxides. The specific operating parameters are as follows: Based on the low-sulfur and high-zinc oxides, in terms of mass percentage, the low-sulfur and high-zinc oxides containing 0.9% S element and 40% Zn element are preliminarily reduced with coke lumps in the first reduction zone, controlling the volume ratio of CO to CO2 to be 20:1, the temperature of the first reduction zone is 1200 °C for 1 h, and the molar ratio of carbon element in the reducing agent to the molar amount of zinc element in the low-sulfur and high-zinc oxides is 0.8:1, obtaining preliminarily reduced materials and a large amount of zinc vapor.

[0059] The preliminarily reduced materials are subjected to a deep reduction reaction with oxygen-rich gas and pulverized coal injected through jet injection in the second reduction zone, controlling the volume ratio of CO to CO2 to be 20:1, the temperature of the second reduction zone is 1350 °C for 1 h, and the molar ratio of carbon element in the reducing agent to the molar amount of zinc element in the low-sulfur and high-zinc oxides is 0.2:1, obtaining iron-containing metal materials and zinc vapor; the zinc vapor contains valuable metals such as cadmium, lead, indium, and germanium. After the zinc vapor is condensed, a crude zinc product is produced. The iron-containing metal materials are pig iron, and the iron element in the low-sulfur and high-zinc oxides is reduced to form pig iron, and copper, gold, and silver are enriched and recovered in the pig iron.

[0060] The crude zinc liquid is refined by a crude zinc rectification system. In the rectification system, first, the temperature of the rectified metal vapor is controlled at 900 °C to separate and recover lead; then, the temperature of the rectified metal vapor is controlled at 500 °C to separate and recover cadmium. The obtained refined zinc contains 99.996% Zn element by mass percentage.

[0061] Example 2

[0062] This embodiment provides a reduction smelting method for low-sulfur and high-zinc oxides. The product obtained by smelting and oxidizing zinc concentrate is used as the low-sulfur and high-zinc oxides. The specific operating parameters are as follows: Based on the low-sulfur and high-zinc oxides, in terms of mass percentage, the low-sulfur and high-zinc oxides containing 0.5% S element and 50% Zn element are preliminarily reduced with crushed coke in the first reduction zone, controlling the volume ratio of CO to CO2 to be 30:1, the temperature of the first reduction zone is 1250 °C for 2 h, and the molar ratio of carbon element in the reducing agent to the molar amount of zinc element in the low-sulfur and high-zinc oxides is 1.0:1, obtaining preliminarily reduced materials and a large amount of zinc vapor.

[0063] The preliminarily reduced material is subjected to a deep reduction reaction with oxygen-rich gas and coke powder entering through jet injection in the second reduction zone to control the volume ratio of CO to CO2 at 30:1. The temperature in the second reduction zone is 1400 °C for 2 hours of reduction. The molar ratio of carbon element in the reducing agent to zinc element in the low-sulfur high-zinc oxide is 0.3:1, obtaining an iron-containing metal material and zinc vapor; the zinc vapor contains valuable metals such as cadmium, lead, indium, and germanium. After the zinc vapor is condensed, a crude zinc product is produced. The iron-containing metal material is pig iron. The iron element in the low-sulfur high-zinc oxide is reduced to form pig iron, and copper, gold, and silver are enriched and recovered in the pig iron.

[0064] The crude zinc liquid is refined through a crude zinc rectification system. In the rectification system, the temperature of the rectified metal vapor is first controlled at 925 °C to separate and recover lead; then, the temperature of the rectified metal vapor is controlled at 550 °C to separate and recover cadmium. The obtained refined zinc contains 99.997% by mass of Zn element.

[0065] Example 3

[0066] This example provides a reduction smelting of low-sulfur high-zinc oxide, where the product after smelting and oxidation of zinc concentrate is used as the low-sulfur high-zinc oxide. The specific operating parameters are as follows: Based on the low-sulfur high-zinc oxide, in terms of mass percentage, the low-sulfur high-zinc oxide containing 0.3% S element and 60% Zn element is subjected to preliminary reduction with coke lumps in the first reduction zone to control the volume ratio of CO to CO2 at 35:1. The temperature in the first reduction zone is 1300 °C for 3 hours of reduction. The molar ratio of carbon element in the reducing agent to zinc element in the low-sulfur high-zinc oxide is 1.2:1, obtaining a preliminarily reduced material and a large amount of zinc vapor.

[0067] The preliminarily reduced material is subjected to a deep reduction reaction with oxygen-rich gas and coke powder entering through jet injection in the second reduction zone to control the volume ratio of CO to CO2 at 35:1. The temperature in the second reduction zone is 1500 °C for 3 hours of reduction. The molar ratio of carbon element in the reducing agent to zinc element in the low-sulfur high-zinc oxide is 0.5:1, obtaining an iron-containing metal material and zinc vapor; the zinc vapor contains valuable metals such as cadmium, lead, indium, and germanium. After the zinc vapor is condensed, a crude zinc product is produced. The iron-containing metal material is pig iron. The iron element in the low-sulfur high-zinc oxide is reduced to form pig iron, and copper, gold, and silver are enriched and recovered in the pig iron.

[0068] The crude zinc liquid is refined through a crude zinc rectification system. In the rectification system, the temperature of the rectified metal vapor is first controlled at 950 °C to separate and recover lead; then, the temperature of the rectified metal vapor is controlled at 600 °C to separate and recover cadmium. The obtained refined zinc contains 99.998% by mass of Zn element.

[0069] Comparative Example 1

[0070] This comparative example is different from Example 3 as follows: Based on the low-sulfur high-zinc oxide, in terms of mass percentage, the low-sulfur high-zinc oxide containing 0.3% S element and 60% Zn element is preliminarily reduced with coke lumps in the first reduction zone, controlling the volume ratio of CO to CO2 to be 10:1. The first reduction zone is reduced for 0.5 h, and the molar ratio of carbon element in the reducing agent to zinc element in the low-sulfur high-zinc oxide is 0.5:1, obtaining preliminarily reduced materials and a small amount of zinc-containing vapor.

[0071] The preliminarily reduced materials are deeply reduced in the second reduction zone with oxygen-enriched gas and coke powder injected by jet injection, controlling the volume ratio of CO to CO2 to be 10:1. The second reduction zone is reduced for 0.5 h, and the molar ratio of carbon element in the reducing agent to zinc element in the low-sulfur high-zinc oxide is 0.1:1. It is impossible to obtain iron-containing metal materials and a small amount of zinc-containing vapor; the zinc-containing vapor contains valuable metals such as cadmium, lead, indium, and germanium. After the zinc-containing vapor is condensed, zinc products are produced. Since iron-containing metal materials (pig iron) cannot be produced, copper, gold, and silver in the low-sulfur high-zinc oxide cannot be enriched and recovered in pig iron.

[0072] Due to insufficient reduction degree, only a small amount of zinc-containing vapor can be produced. A small amount of crude zinc liquid is refined through the crude zinc rectification system. In the rectification system, the temperature of the rectified metal vapor is first controlled at 950 °C to separate and recover lead; then, the temperature of the rectified metal vapor is controlled at 600 °C to separate and recover cadmium. The obtained refined zinc contains 99.998% Zn.

[0073] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0074] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present application. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present application.

Claims

1. A reduction smelting method for low-sulfur and high-zinc oxide, characterized in that, It includes the following steps: The low-sulfur high-zinc oxide is preliminarily reduced with a first reducing agent in a first reduction zone to obtain preliminarily reduced material; The preliminarily reduced material is subjected to a deep reduction reaction with oxygen-rich gas and a carbonaceous reducing agent entering through jet injection in a second reduction zone to obtain an iron-containing metal material and zinc vapor; wherein the molar ratio of carbon element in the carbonaceous reducing agent to zinc element in the low-sulfur high-zinc oxide is 0.2 - 0.5:1; the zinc vapor is condensed to produce crude zinc liquid; the crude zinc liquid is rectified to obtain refined zinc; Wherein the volume ratio of CO to CO2 in the first reduction zone and the second reduction zone is 20 - 35:

1.

2. The method according to claim 1, wherein Based on the low-sulfur high-zinc oxide, by mass percentage, the sulfur element content in the low-sulfur high-zinc oxide is ≤1%, and the Zn element content is ≥25%; And / or, the first reduction zone is electrically heated for reduction, which uses electrode heat supplement, and the reduction smelting temperature is 1200 - 1300°C; And / or, the first reducing agent includes at least one of coke lumps, crushed coke, and anthracite lumps; it is added through the feeding port of the first reduction zone; And / or, the molar ratio of carbon element in the first reducing agent to zinc element in the low-sulfur high-zinc oxide is 0.8 - 1.2:

1.

3. The method according to claim 1 or 2, characterized in that, The second reduction zone is jet injection combustion reduction, and the reduction smelting temperature is 1350 - 1500°C; And / or, the carbonaceous reducing agent includes coke powder and / or coal powder; And / or, the injection amount of the oxygen-rich gas is 0.1 - 0.5 of the total volume of oxygen required for complete combustion of the carbonaceous reducing agent in the second reduction zone; And / or, the oxygen concentration of the oxygen-rich gas is 23 - 99.8%, and the pressure is 0.2 - 0.5 MPa.

4. The method according to claim 2, characterized in that, The time for the preliminary reduction and deep reduction reaction of the low-sulfur high-zinc oxide is 2 - 6 h per furnace; And / or, the time for the preliminary reduction of the low-sulfur high-zinc oxide is 1 - 3 h per furnace; And / or, the time for the deep reduction reaction of the preliminarily reduced material is 1 - 3 h per furnace.

5. The method according to claim 3, characterized in that The heat supplement ratio of the first reduction zone to the second reduction zone is 2 - 5:

1.

6. The method according to claim 3, wherein The iron-containing metal material includes pig iron and copper metal, gold metal, and silver metal.

7. The method according to claim 3, characterized in that During the rectification of the crude zinc liquid, first control the vapor temperature at 900 - 950°C to separate and recover lead metal; then control the vapor temperature at 500 - 600°C to obtain refined zinc, and at the same time enrich cadmium metal, indium metal, and germanium metal to hard zinc.

8. The method according to claim 3, characterized in that The recovery rate of zinc in the low-sulfur high-zinc oxide is 97% - 98%, the recovery rate of lead is 97% - 98%, the recovery rate of copper is 90% - 95%, the recovery rate of cadmium is 90% - 95%, the recovery rate of gold is 90% - 95%, the recovery rate of silver is 90% - 95%, the recovery rate of indium is 90% - 95%, and the recovery rate of germanium is 90% - 95%.

9. The method according to claim 3, characterized in that, The purity of the refined zinc > 99.995%.

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