Method for synchronous sulfur fixation and recovery of metal zinc from complex oxygen-sulfur mixed lead-zinc ore

Abstract

The invention provides a method for synchronous sulfur fixation and recovery of metal zinc from complex oxygen-sulfur mixed lead-zinc ore, and relates to the field of metal production or refining. According to the method, the technological method of pelletizing (wherein the molar ratio of CaO to ZnS is (1-1.5): 1, and the addition amount of a carbonaceous reducing agent is 10-15%), high-temperature sulfur fixation reduction treatment at the temperature of 1100-1300 DEG C and condensation recovery are adopted, and synchronous and efficient sulfur fixation and metal zinc recovery are achieved. Wherein the reduction volatilization rate of zinc is as high as 98.8%; and the synchronous sulfur fixation rate can reach 85.5%. And the method greatly improves the utilization rate of the carbonaceous reducing agent, greatly reduces the carbon consumption, and can be used for obtaining a silicon dioxide product and an iron product through simple separation treatment subsequently. The method also has the advantages of simple process flow, reduction of emission of exhaust gases such as SO2, reduction of environmental pollution and the like, has good economic benefits and environmental benefits, and has a wide application prospect.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of metal production or refining, and particularly relates to a method for simultaneously recovering metallic zinc and solidifying sulfur from a complex oxygen-sulfur mixed lead-zinc ore. BACKGROUND

[0002] With the continuous exploitation and utilization of zinc sulfide ore resources, untreated low-grade oxygen-sulfur mixed lead-zinc tailings (complex oxygen-sulfur mixed lead-zinc ore) are seriously stacked, but they contain rich zinc resources and have considerable potential economic value. The comprehensive utilization of tailings is of great significance to the sustainable development of the lead-zinc smelting industry and the alleviation of environmental pollution near the mine.

[0003] However, due to the difficulty in processing, many low-grade ores have not been effectively utilized for a long time, and the potential of resource development has not been fully released. The particularity of such ores lies in the complexity of their mineral composition. The ores have low lead-zinc grade, high calcium-silicon content, and oxidized and sulfidic minerals are interbedded in a state of association, and multiple metals are associated. The diversity of mineral phases makes it difficult to directly apply conventional beneficiation and smelting processes, and the smelting cost is high.

[0004] For such low-grade oxygen-sulfur mixed ores (complex oxygen-sulfur mixed lead-zinc ore), many traditional beneficiation processes, such as sulfide flotation, gravity separation, roasting-leaching, and combined beneficiation and smelting processes, all show significant limitations. In existing research reports on such ores, a combined process of smelting followed by beneficiation is adopted. By selective leaching of the oxidized zinc therein, a zinc sulfate solution and a leaching residue are separated. The zinc sulfate solution obtained is subjected to extraction, electrodeposition and casting processes to obtain a zinc product, and the leaching residue is subjected to flotation by referring to conventional flotation processes to obtain a zinc sulfide concentrate and a lead sulfide concentrate, and the tailings are disposed of by stacking. The existing combined process of smelting followed by beneficiation for processing complex oxygen-sulfur mixed ores has the problems of long process flow and low direct metal recovery. Traditional wet zinc smelting processes are difficult to effectively treat such complex oxygen-sulfur mixed lead-zinc ores, and have the bottlenecks of low zinc recovery and high production cost. The combined process of pyrometallurgical-hydrometallurgical treatment has the problems of high energy consumption, high pollution and high production cost, and the generated SO2 and dust will cause environmental pollution. SUMMARY

[0005] The main purpose of the present application is to provide a method for simultaneously recovering metallic zinc and solidifying sulfur from a complex oxygen-sulfur mixed lead-zinc ore, which aims to solve the problems of limitations of efficient simultaneous solidification of sulfur and recovery of metallic zinc, complicated process flow, high cost and the like when recovering metallic zinc and simultaneously solidifying sulfur from a complex oxygen-sulfur mixed lead-zinc ore by using the prior art.

[0006] To achieve the above-mentioned purpose, the present application provides a method for simultaneously recovering metallic zinc and solidifying sulfur from a complex oxygen-sulfur mixed lead-zinc ore, comprising the steps of:

[0007] The complex oxide-sulfide mixed lead-zinc ore is provided with a mixture of lime, carbonaceous reducing agent and bentonite; the molar ratio of CaO to ZnS in the mixture is 1-1.5:1; the addition amount of the carbonaceous reducing agent is 10-15%, and the addition amount of the bentonite is 3-5%.

[0008] The mixture is subjected to balling treatment to obtain pellets; the particle size of the pellets is 11-20 mm.

[0009] The pellets are sequentially subjected to preheating treatment, high-temperature sulfur-fixing reduction treatment and condensation recovery treatment in a reducing atmosphere or a chemically inert atmosphere to obtain sulfur-fixing slag and metallic zinc.

[0010] The complex oxide-sulfide mixed lead-zinc ore includes, by mass fraction, not more than 40% of zinc grade and more than 20% of gangue; the temperature of the high-temperature sulfur-fixing reduction treatment is 1100-1300°C.

[0011] Further, the complex oxide-sulfide mixed lead-zinc ore includes, by mass fraction, 5-40% of the zinc grade, 1-20% of lead grade, 2-11% of sulfur grade and more than 20% of the gangue.

[0012] Further, the source of the complex oxide-sulfide mixed lead-zinc ore includes one or more of oxidized lead / zinc ore, sulfidic lead-zinc ore and oxide-sulfide mixed lead-zinc ore.

[0013] Further, the water content of the pellets is <5%.

[0014] Further, the reducing atmosphere includes CH4 and / or CO; and the chemically inert atmosphere includes N2 and / or Ar.

[0015] Further, the gas flow rate of the reducing atmosphere and the chemically inert atmosphere is both 100-500 mL / min.

[0016] Further, the temperature of the preheating treatment is 500-900°C.

[0017] Further, the preheating treatment is performed by using hot air generated by heat exchange of the reducing atmosphere or the chemically inert atmosphere to heat the pellets to 500-900°C.

[0018] Further, the duration of the high-temperature sulfur-fixing reduction treatment is 20-40 min.

[0019] Further, the condensation recovery treatment is performed by spraying zinc rain on the mixed gas after the high-temperature sulfur-fixing reduction treatment; the temperature of the zinc rain is 590-610°C; the spraying flow rate of the zinc rain is 0.6-1.2 m 3 / min.

[0020] The present application achieves the following beneficial effects:

[0021] The method for simultaneously recovering zinc and sulfur in complex oxide-sulfur mixed lead-zinc ore provided by the present application adopts the process method of "pelletizing (the molar ratio of CaO to ZnS is 1-1.5:1; the addition amount of carbonaceous reducing agent is 10-15%) + high-temperature sulfur-fixing reduction treatment at 1100-1300°C + condensation recovery", realizing the simultaneous and efficient recovery of sulfur and zinc. Among them, the zinc reduction and volatilization rate is as high as 98.8%; the simultaneous sulfur-fixing rate can reach 85.5%.

[0022] In addition, the method greatly improves the utilization rate of carbonaceous reducing agent, greatly reduces carbon consumption, and can further obtain silicon dioxide products and iron products through simple separation and treatment. The method also has the advantages of simple process flow, reduced SO2 and other waste gas emissions, reduced environmental pollution, etc., good economic and environmental benefits, and wide application prospect. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiment or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from the structures shown in these drawings without creative labor.

[0024] Figure 1 X-ray diffraction (XRD) patterns of the treatment objects of Examples 1-4 and Comparative Examples 1-4 of the present application;

[0025] Figure 2 Scanning electron microscope-X-ray energy spectrometer (SEM-EDS) patterns of the treatment objects of Examples 1-4 and Comparative Examples 1-4 of the present application;

[0026] Figure 3 Scanning electron microscope-X-ray energy spectrometer (SEM-EDS) patterns of the sulfur-fixing slag of Example 1 of the present application.

[0027] The implementation, functional features and advantages of the present application will be further described with reference to the embodiments and the accompanying drawings. DETAILED DESCRIPTION

[0028] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative efforts belong to the scope of the present application.

[0029] It should be noted that the following examples and features in the examples can be combined with each other without conflict. It should also be understood that the terms used in the embodiments of the present application are used to describe specific specific embodiments, rather than to limit the protection scope of the present application.

[0030] Unless otherwise defined, all technical and scientific terms used in the present application are used in the same meaning as the present technical field of the skilled person and the description of the present application, and any method, equipment and material of the prior art similar or equivalent to the method, equipment and material described in the embodiments of the present application can be used to realize the present application. When the embodiments give a numerical range, it should be understood that, unless otherwise specified by the present application, each numerical range and any numerical value between the two endpoints can be selected. The test method in the following examples is not specified, which is usually carried out under conventional conditions, or under the conditions recommended by the manufacturer. The materials or reagents required in the following examples, unless otherwise specified, are commercially available.

[0031] In order to solve the problems of high efficient simultaneous sulfur fixation and metal zinc recovery, complicated process, high cost and other problems in the prior art for simultaneously fixing sulfur and recovering metal zinc from complex oxygen-sulfur mixed lead-zinc ore, the present application provides a method for simultaneously fixing sulfur and recovering metal zinc from complex oxygen-sulfur mixed lead-zinc ore, comprising the steps of:

[0032] The mixture of complex oxygen-sulfur mixed lead-zinc ore, lime, carbonaceous reducing agent and bentonite is provided; in the mixture, the molar ratio of CaO to ZnS is 1-1.5:1; the addition amount of carbonaceous reducing agent is 10-15%, and the addition amount of bentonite is 3-5%. Specifically, the ratio of each component of complex oxygen-sulfur mixed lead-zinc ore, lime, carbonaceous reducing agent and bentonite is adjusted so that the obtained mixture satisfies the molar ratio of CaO to ZnS of 1-1.5:1, so that the CaO, FeO xThe metal oxides in situ as the sulfur-fixing agent help the subsequent system to have a reduction sulfurization reaction, break through the limitation that ZnS cannot be directly reduced and recovered in the traditional fire and wet metallurgical processes, realize one-step obtaining of metal zinc and simultaneous sulfur fixation, and reduce the need for additional sulfur-fixing agent, thereby greatly improving the resource utilization rate compared with the traditional fire reduction process such as the closed blast furnace zinc smelting (ISP) and the electric furnace zinc smelting. The carbonaceous reducing agent with an addition amount of 10-15% can effectively prevent the subsequent prepared pellets from being pulverized under the condition of greatly reducing the carbon consumption. It is found in the experimental study that if the pellets are pulverized, the airflow channel will be blocked, the kiln lining will be abnormally consumed, and the zinc reduction volatilization rate (the recovery amount of zinc) will be reduced.

[0033] The mixture is subjected to a pelletizing treatment to obtain pellets; the particle size of the pellets is 11-20 mm.

[0034] The pellets are sequentially subjected to a preheating treatment, a high-temperature sulfur-fixing reduction treatment and a condensation recovery treatment in a reducing atmosphere or a chemically inert atmosphere to obtain sulfur-fixing residues and metal zinc.

[0035] The complex oxygen-sulfur mixed lead-zinc ore includes, by mass fraction, not more than 40% of zinc grade and more than 20% of gangue; the temperature of the high-temperature sulfur-fixing reduction treatment is 1100-1300°C. The pellets after the preheating treatment can not only realize simultaneous and efficient sulfur fixation and recovery of metal zinc at 1100-1300°C, but also reduce a large amount of iron in the mixture into metallic iron and ferrous sulfide; the iron metallization rate of the sulfur-fixing residues is high, and the silicon dioxide is still in a monomer state and has not formed complex silicates; after simple separation of the sulfur-fixing residues, silicon dioxide products and iron products can be obtained. The specific reactions can include the following:

[0036] ZnS(s)+CaO(s)+C(s)=CaS(s)+CO(g)+Zn(g)

[0037] ZnS+CaO+CO(g)=CaS+CO2(g)+Zn(g)

[0038] ZnS+C+CaSiO3=Zn(g)+SiO2+CaS+CO(g)

[0039] ZnS+CO(g)+CaSiO3=Zn(g)+SiO2+CaS+CO2(g)

[0040] Zn2SiO4+2C=2Zn(g)+2CO(g)+SiO2

[0041] ZnO+C=Zn(g)+CO(g)

[0042] ZnO+CO(g)=Zn(g)+CO2(g).

[0043] Preferably, the molar ratio of carbon element to oxygen element in the carbonaceous reducing agent is 0.9-1.2:1.

[0044] The method for simultaneously recovering zinc from complex oxygen-sulfur mixed lead-zinc ore provided by the application adopts the process of "pelletizing (the molar ratio of CaO to ZnS is 1-1.5:1; the addition amount of carbonaceous reducing agent is 10-15%) + high-temperature sulfur-fixing reduction treatment at 1100-1300°C + condensation recovery", and realizes the simultaneous and efficient sulfur fixation and zinc recovery. The zinc reduction and volatilization rate is as high as 98.8%, and the simultaneous sulfur fixation rate can reach 85.5%.

[0045] In addition, the method greatly improves the utilization rate of the carbonaceous reducing agent and greatly reduces the carbon consumption. Subsequently, silicon dioxide and iron products can be obtained through simple separation and treatment. The method also has the advantages of simple process flow, reduced SO2 and other waste gas emissions, reduced environmental pollution, etc., and has good economic and environmental benefits, and has a wide application prospect.

[0046] Further, the complex oxygen-sulfur mixed lead-zinc ore includes, by mass fraction, 5-40% zinc grade, 1-20% lead grade, 2-11% sulfur grade, and more than 20% gangue. Specifically, the complex oxygen-sulfur mixed lead-zinc ore with 5-40% zinc grade, 1-20% lead grade, 2-11% sulfur grade, and more than 20% gangue has a complex mineral composition, low lead-zinc grade, high calcium-silicon content, and oxidized and sulfidic minerals interbedded in a associated state, and multiple metals are associated, and the diversity of mineral phases makes it difficult to directly apply conventional beneficiation and smelting processes, and the smelting cost is high. Using existing processes to treat such complex oxygen-sulfur mixed lead-zinc ore often has problems such as low zinc recovery rate and high production cost, and it is difficult to achieve short-flow efficient simultaneous sulfur fixation and zinc recovery. In an optional embodiment, the gangue includes quartz and calcite.

[0047] Further, the source of the complex oxygen-sulfur mixed lead-zinc ore includes one or more of oxidized lead / zinc ore, sulfidic lead-zinc ore, and oxygen-sulfur mixed lead-zinc ore.

[0048] Further, the water content of the pellets is <5%. Specifically, in an optional embodiment, the pelletizing treatment is performed by gradient drying the pellet-shaped mixture at 80-250°C to obtain pellets with a water content of <5%. Preferably, the pelletizing treatment further includes a drying treatment before the pelletizing treatment; the drying treatment is performed by feeding the mixture into a drying device until the water content of the dried product is 8-12% to ensure the mechanical strength of the pellets obtained by the pelletizing treatment.

[0049] Further, the reducing atmosphere includes CH4 and / or CO; and the chemically inert atmosphere includes N2 and / or Ar.

[0050] Further, the flow rate of the reducing atmosphere and the chemically inert atmosphere is 100-500 mL / min. Specifically, the reducing atmosphere can be ensured by introducing CH4 and / or CO at the flow rate, and the inert atmosphere can be ensured by introducing N2 and / or Ar to prevent the reduced metal from being re-oxidized.

[0051] Further, the temperature of the pre-heating treatment is 500-900°C. Specifically, the pre-reaction of reduction occurs at this stage to obtain ZnO and CaO. The reactions are as follows:

[0052] ZnCO3= CO2(g) + ZnO

[0053] CaCO3= CaO + CO2(g).

[0054] Further, the pre-heating treatment is performed by using the hot air generated by heat exchange of the reducing atmosphere or the chemically inert atmosphere to heat the pellets to 500-900°C. Preferably, the pre-heating treatment is performed by using the hot air generated by heat exchange of coal gas to ensure that the pellets reach the desired temperature.

[0055] Further, the duration of the high-temperature sulfur-fixing reduction treatment is 20-40 min. Specifically, the high-temperature sulfur-fixing reduction treatment for 20-40 min can improve the production efficiency while ensuring complete sulfur-fixing reduction.

[0056] Further, the condensation recovery treatment is performed by spraying the mixed gas after the high-temperature sulfur-fixing reduction treatment with zinc rain; the temperature of the zinc rain is 590-610°C; and the spraying flow rate of the zinc rain is 0.6-1.2 m 3 / min. Specifically, the anti-oxidation effect of zinc metal is closely related to the temperature and the flow rate of the zinc rain, and the anti-oxidation rate of zinc vapor reaches the maximum, which can be as high as 98%, under the conditions.

[0057] To further understand the present application, examples are provided as follows:

[0058] Example 1

[0059] The oxygen-sulfur mixed lead-zinc ore produced by the "oxygen-sulfur simultaneous flotation technology for oxygen-sulfur mixed lead-zinc ore" was used as the raw material. The carbonaceous reducing agent was coke provided by Xiangtan Iron and Steel Group Co., Ltd.

[0060] The chemical composition of the oxygen-sulfur mixed lead-zinc ore and the coke is shown in Table 1 and Table 2, respectively.

[0061] Table 1 Chemical composition of the oxygen-sulfur mixed lead-zinc ore

[0062]

[0063] Table 2 Chemical composition table of the coke

[0064]

[0065] The oxygen-sulfur mixed lead-zinc ore was characterized; the corresponding X-ray diffraction (XRD) pattern is shown in Figure 1 ; the corresponding scanning electron microscope-X-ray energy spectrometer (SEM-EDS) pattern is shown in Figure 2 .

[0066] In combination with Figure 1 , Figure 2 , the chemical composition of the oxygen-sulfur mixed lead-zinc ore is mainly zinc, lead, sulfur, iron, silicon and calcium. The phases and distribution of the oxygen-sulfur mixed ore are determined by XRD and SEM-EDS analysis, and it can be seen from Figure 2 that most of the Zn in the oxygen-sulfur mixed ore is consistent with the distribution of O, and most of the Pb and Fe are combined with S. In combination with the quantitative phase analysis results, it is judged that about 70% of the Zn in the oxygen-sulfur mixed ore exists in the form of ZnCO3 in the oxidized state, and 30% exists in the form of ZnS in the sulfidized state; the total lead accounts for only 1.52%, of which 85% is in the form of PbS, and a small amount is in the oxidized state, and the XRD does not detect the oxidized lead phase because its content is lower than the detection limit; and the content of gangue quartz (SiO2) and calcite (CaCO3) in the concentrate is as high as 19.51% and 23.12%, respectively.

[0067] 0.1 kg of oxygen-sulfur mixed lead-zinc ore is mixed with lime, coke and bentonite to obtain a mixture; the molar ratio of CaO to ZnS in the mixture is 1.5:1; the addition amount of coke is 15%; and the addition amount of bentonite is 3%. The mixture is sequentially subjected to drying treatment and pelletizing treatment to prepare pellets (the particle size of the pellets is 15 mm, and the water content is 4%).

[0068] The pellets are loaded into a gas atmosphere tube furnace, and N2 / Ar mixed gas is introduced (the gas introduction flow rate is 300 mL / min), and the hot air generated by heat exchange of the mixed gas is used for preheating treatment (the preheating treatment temperature is 600°C). High-temperature sulfur-fixing reduction treatment is carried out at 1200°C for 40 min, and after the preset reaction time, the obtained sulfur-fixing residue is rapidly cooled to room temperature in liquid nitrogen to retain the original morphology of the pellets. The pellets (sulfur-fixing residue) after reduction do not powder, and the main phases are CaS, FeS, CaSiO3, SiO2, the calculated Zn reduction and volatilization rate is 98.8%, and the sulfur-fixing rate is 85.5%.

[0069] The gas generated after high-temperature sulfur-fixing reduction treatment is subjected to zinc rain spraying (the temperature of the zinc rain is 600°C; the spraying flow rate of the zinc rain is 1 m 3 / min), and zinc metal is obtained, and the oxygen resistance rate of the zinc metal is 98%.

[0070] The pellets after reduction (sulfur-fixing slag) were characterized; a scanning electron microscope-X-ray energy dispersive spectrometer (SEM-EDS) diagram thereof is shown in FIG. 1. Figure 3 As can be seen from FIG. 1, in the phase composition of the sulfur-fixing slag, Zn is reduced and volatilized, and the slag phase is mainly composed of SiO2, CaS, FeS and ZnS. A large amount of newly generated CaS encapsulates a small amount of ZnS-FeS, verifying the sulfur-fixing effect and reaction path of Ca. Figure 3

[0071] Example 2

[0072] The same oxygen-sulfur mixed lead-zinc ore and coke as in Example 1 were used for the experiment.

[0073] 0.1 kg of the oxygen-sulfur mixed lead-zinc ore was uniformly mixed with lime, coke and bentonite to obtain a mixture; the molar ratio of CaO to ZnS in the mixture was 1:1; the addition amount of coke was 10%; and the addition amount of bentonite was 3%. The mixture was sequentially subjected to drying treatment and pelletizing treatment to prepare pellets (the particle size of the pellets was 15 mm, and the water content was 3%).

[0074] The pellets were loaded into an atmosphere tube furnace, CO gas was introduced (the gas introduction flow rate was 500 mL / min), and preheating treatment was performed by using the hot air generated by heat exchange of the CO gas (the preheating treatment temperature was 700°C). High-temperature sulfur-fixing reduction treatment was performed at 1200°C for 40 min. After the preset reaction time, the sulfur-fixing slag obtained was rapidly cooled to room temperature in liquid nitrogen to retain the original morphology of the pellets. The pellets after reduction (sulfur-fixing slag) were not powdered, and the main phases were still CaS, FeS, CaSiO3 and SiO2. The calculation showed that the reduction and volatilization rate of Zn was 98.1%, and the sulfur-fixing rate was 80.3%.

[0075] Zinc rain spraying was performed on the gas generated after high-temperature sulfur-fixing reduction treatment (the temperature of the zinc rain was 590°C; the spraying flow rate of the zinc rain was 0.6 m 3 / min), and metallic zinc was obtained. The oxygen inhibition rate of the zinc metal was 97%.

[0076] Example 3

[0077] The same oxygen-sulfur mixed lead-zinc ore and coke as in Example 1 were used for the experiment.

[0078] 0.1 kg of the oxygen-sulfur mixed lead-zinc ore was uniformly mixed with lime, coke and bentonite to obtain a mixture; the molar ratio of CaO to ZnS in the mixture was 1:1; the addition amount of coke was 10%; and the addition amount of bentonite was 3%. The mixture was sequentially subjected to drying treatment and pelletizing treatment to prepare pellets (the particle size of the pellets was 20 mm, and the water content was 4%).

[0079] ​The pellets are loaded into an atmosphere tube furnace, and N2 / Ar mixed gas is introduced (gas flow rate is 300 mL / min), and preheating treatment is performed by hot air generated by mixed gas heat exchange (preheating treatment temperature is 500℃). High-temperature sulfur-fixing reduction treatment is performed at 1300℃ for 20 min, and after the preset reaction time, the obtained sulfur-fixing residue is rapidly cooled to room temperature in liquid nitrogen to retain the original morphology of the pellets. The reduced pellets (sulfur-fixing residue) are not powdered, and the main phases are still CaS, FeS, CaSiO3, and SiO2. The calculated Zn reduction and volatilization rate is 90.9%, and the sulfur-fixing rate is 77.5%.

[0080] The gas generated after high-temperature sulfur-fixing reduction treatment is sprayed with zinc rain (zinc rain temperature is 610℃; zinc rain spraying flow rate is 1.2m 3 / min), and metal zinc is obtained, and the zinc metal oxidation inhibition rate is 98%.

[0081] Example 4

[0082] The same oxygen-sulfur mixed lead-zinc ore and coke as in Example 1 are used for the experiment.

[0083] 0.1 kg of oxygen-sulfur mixed lead-zinc ore is mixed with lime, coke, and bentonite to obtain a mixture; the molar ratio of CaO to ZnS in the mixture is 1.5:1; the addition amount of coke is 15%; and the addition amount of bentonite is 3%. The mixture is sequentially subjected to drying treatment and pelletizing treatment to prepare pellets (pellet particle size is 11 mm, and water content is 4%).

[0084] The pellets are loaded into an atmosphere tube furnace, and N2 / Ar mixed gas is introduced (gas flow rate is 300 mL / min), and preheating treatment is performed by hot air generated by mixed gas heat exchange (preheating treatment temperature is 900℃). High-temperature sulfur-fixing reduction treatment is performed at 1100℃ for 40 min, and after the preset reaction time, the obtained sulfur-fixing residue is rapidly cooled to room temperature in liquid nitrogen to retain the original morphology of the pellets. The reduced pellets (sulfur-fixing residue) are not powdered, and the main phases are CaS, ZnS, and SiO2. The calculated Zn reduction and volatilization rate is 81.3%, and the sulfur-fixing rate is 90.7%, and carbon thermal reduction of oxidized Zn and a small amount of sulfur-fixing reduction of Zn in sulfide state occur.

[0085] The gas generated after high-temperature sulfur-fixing reduction treatment is sprayed with zinc rain (zinc rain temperature is 590℃; zinc rain spraying flow rate is 1.2m 3 / min), and metal zinc is obtained, and the zinc metal oxidation inhibition rate is 96%.

[0086] Comparative Example 1

[0087] The same oxygen-sulfur mixed lead-zinc ore and coke as in Example 1 are used for the experiment.

[0088] 0.1 kg of the oxygen-sulfur mixed lead-zinc ore was mixed with 5% of the coke and 3% of the bentonite to obtain a mixture. The mixture was sequentially subjected to drying treatment and pelletizing treatment to prepare the pellets (the particle size of the pellets was 15 mm, and the water content was 3%).

[0089] The pellets were loaded into an atmosphere tube furnace, N2 / Ar mixed gas was introduced (the gas introduction flow rate was 300 mL / min), and preheating treatment was performed by using the hot air generated by heat exchange of the mixed gas (the preheating treatment temperature was 600 ℃). High-temperature sulfur-fixing reduction treatment was performed at 1100 ℃ for 40 min, and after the preset reaction time, the obtained sulfur-fixing residue was rapidly cooled to room temperature in liquid nitrogen to retain the original morphology of the pellets. After reduction, the pellets (sulfur-fixing residue) were not powdered, the main phases were CaS, ZnS and SiO2, the calculated Zn reduction and volatilization rate was 51.3%, the sulfur-fixing rate was 93.7%, and the coke was insufficient to completely reduce and volatilize Zn.

[0090] Comparative Example 2

[0091] The same oxygen-sulfur mixed lead-zinc ore and coke as in Example 1 were used for the experiment.

[0092] 0.1 kg of the oxygen-sulfur mixed lead-zinc ore was mixed with 15% of the coke and 3% of the bentonite to obtain a mixture. The mixture was sequentially subjected to drying treatment and pelletizing treatment to prepare the pellets (the particle size of the pellets was 11 mm, and the water content was 4%).

[0093] The pellets were loaded into an atmosphere tube furnace, N2 / Ar mixed gas was introduced (the gas introduction flow rate was 300 mL / min), and preheating treatment was performed by using the hot air generated by heat exchange of the mixed gas (the preheating treatment temperature was 400 ℃). High-temperature sulfur-fixing reduction treatment was performed at 800 ℃ for 40 min, and after the preset reaction time, the obtained sulfur-fixing residue was rapidly cooled to room temperature in liquid nitrogen to retain the original morphology of the pellets. After reduction, the pellets (sulfur-fixing residue) were not powdered, the main phases were CaCO3, CaO, ZnS, CaZnSO and SiO2, the calculated Zn reduction and volatilization rate was 30.3%, CaCO3 was not completely decomposed, and the sulfur-fixing reduction temperature was not reached.

[0094] Comparative Example 3

[0095] The same oxygen-sulfur mixed lead-zinc ore and coke as in Example 1 were used for the experiment.

[0096] 0.1 kg of the oxygen-sulfur mixed lead-zinc ore was mixed with 15% of the coke and 3% of the bentonite to obtain a mixture. The mixture was sequentially subjected to drying treatment and pelletizing treatment to prepare the pellets (the particle size of the pellets was 11 mm, and the water content was 4%).

[0097] The pellets are loaded into an atmosphere tube furnace, O2 gas is introduced (gas flow rate is 300 mL / min), and preheating treatment is performed by hot air generated by O2 gas heat exchange (preheating treatment temperature is 600 DEG C). High-temperature sulfur-fixing reduction treatment is performed at 1200 DEG C for 20 min, and after the preset reaction time, the obtained sulfur-fixing slag is rapidly cooled to room temperature in liquid nitrogen to retain the original morphology of the pellets. The pellets (sulfur-fixing slag) after reduction are not powdered, the main phases are CaSiO3, Zn2SiO4 and SiO2, the calculated Zn reduction and volatilization rate is 85.3%, the sulfur-fixing rate is 11.1%, and a small amount of pellets are melted, in a strong oxidizing atmosphere, oxidation desulfurization occurs to produce low-concentration SO2, and the sulfur-fixing rate is greatly reduced.

[0098] Comparative Example 4

[0099] The same oxygen-sulfur mixed lead-zinc ore and coke as in Example 1 are used for the experiment.

[0100] 0.1 kg of oxygen-sulfur mixed lead-zinc ore is uniformly mixed with 15% coke and 3% bentonite to obtain a mixture. The mixture is sequentially subjected to drying treatment and pelletizing treatment to prepare pellets (the particle size of the pellets is 15 mm, and the water content is 8%).

[0101] The pellets are loaded into an atmosphere tube furnace, N2 / Ar mixed gas is introduced (gas flow rate is 300 mL / min), and preheating treatment is performed by hot air generated by mixed gas heat exchange (preheating treatment temperature is 900 DEG C). High-temperature sulfur-fixing reduction treatment is performed at 1200 DEG C for 40 min, and after the preset reaction time, the obtained sulfur-fixing slag is rapidly cooled to room temperature in liquid nitrogen to retain the original morphology of the pellets. It is found that the pellets are powdered and difficult to consolidate.

[0102] In summary, the above technical solutions of the present application are preferred embodiments of the present application, and do not limit the patent scope of the present application. Any equivalent structural transformation, direct / indirect application in other related technical fields, or use of the contents of the present application specification and drawings within the technical concept of the present application are included in the patent protection scope of the present application.

Claims

1. A method for simultaneous sulphur fixation and zinc recovery from complex sulphide-oxide lead-zinc ores, characterized by, The method comprises the steps of: providing a mixture of a complex oxide-sulfide mixed lead-zinc ore, lime, carbonaceous reducing agent and bentonite; the molar ratio of CaO to ZnS in the mixture is 1-1.5:1; the addition amount of the carbonaceous reducing agent is 10-15%, and the addition amount of the bentonite is 3-5%; performing briquetting treatment on the mixture to obtain briquettes; the particle size of the briquettes is 11-20 mm; performing preheating treatment, high-temperature sulfur-fixing reduction treatment and condensation recovery treatment on the briquettes in a reducing atmosphere or a chemically inert atmosphere in sequence to obtain sulfur-fixing residues and metallic zinc; wherein the complex oxide-sulfide mixed lead-zinc ore comprises a zinc grade of not more than 40% and gangue of more than 20% by mass; and the temperature of the high-temperature sulfur-fixing reduction treatment is 1100-1300°C.

2. The process for simultaneous sulphur fixation and zinc recovery from complex sulphide-oxide lead-zinc ores as claimed in claim 1 wherein, The complex oxide-sulfide mixed lead-zinc ore comprises a zinc grade of 5-40%, a lead grade of 1-20%, a sulfur grade of 2-11% and gangue of more than 20% by mass.

3. The process for simultaneous sulphur fixation and zinc recovery from complex sulphide-oxide lead-zinc ores as claimed in claim 2 wherein, The source of the complex oxide-sulfide mixed lead-zinc ore comprises one or more of oxidized lead / zinc ore, sulfidic lead-zinc ore and oxide-sulfide mixed lead-zinc ore.

4. The process for simultaneous sulphur fixation and zinc recovery from complex sulphide-oxide lead-zinc ores as claimed in claim 1 wherein, The water content of the briquettes is less than 5%.

5. The process for simultaneous sulphur fixation and zinc recovery from complex sulphide-oxide lead-zinc ores as claimed in claim 1 wherein, The reducing atmosphere comprises CH4 and / or CO; and the chemically inert atmosphere comprises N2 and / or Ar.

6. The process for simultaneous sulphur fixation and zinc recovery from complex sulphide-oxide lead-zinc ores as claimed in claim 4 wherein, The gas flow rate of the reducing atmosphere and the chemically inert atmosphere is 100-500 mL / min.

7. The process for simultaneous sulphur retention and zinc recovery from complex sulphide-oxide lead-zinc ores as claimed in claim 1 wherein, The temperature of the preheating treatment is 500-900°C.

8. The process for simultaneous sulphur fixation and zinc recovery from complex sulphide-oxide lead-zinc ores as claimed in claim 7 wherein, The preheating treatment is performed by using hot air generated by heat exchange between the reducing atmosphere or the chemically inert atmosphere to heat the briquettes to 500-900°C.

9. The process for simultaneous sulphur retention and zinc recovery from complex sulphidic lead-zinc ore as claimed in claim 1 wherein, The duration of the high-temperature sulfur-fixing reduction treatment is 20-40 min.

10. The process for simultaneous sulphur retention and zinc recovery from complex sulphide-oxide lead-zinc ores as claimed in claim 1 wherein, The condensing recovery treatment is zinc rain spraying on the mixed gas after the high-temperature sulfur reduction treatment; the temperature of the zinc rain is 590-610 DEG C; the spraying flow of the zinc rain is 0.6-1.2 m 3 / min.

Images