Method and device for recovering high-purity pyrite by utilizing sulfur-containing reducing gas to strengthen conversion of ferrous sulfate

Abstract

The invention belongs to the technical field of material synthesis, energy and environmental protection, and particularly relates to a method and a device for reinforcing conversion and recovery of high-purity pyrite by using sulfur-containing reducing gas and ferrous sulfate. Sulfur-containing raw material gases such as hydrogen sulfide, carbonyl sulfide and the like and accelerators are conveyed to a gas mixing tank by a storage unit according to a certain proportion to be fully mixed, then the mixed gas is introduced into a temperature control reactor to be subjected to a vulcanization reaction with a ferrous sulfate material to generate FeS2 and Fe7S8 products respectively, generated SO2 tail gas enters a recovery unit to be comprehensively recovered, and the accelerators are H2 and CO respectively. Compared with the prior art, the method effectively solves the problems of high pyrolytic reaction temperature, difficulty in purification and impurity removal and the like in the recovery process of pyrite resources in the ferrous sulfate, reduces the reaction conversion temperature, accelerates the reaction rate, and improves the purity of pyrite products and the gas concentration of SO2 products, so that the comprehensive utilization performance of the ferrous sulfate is remarkably improved.

Description

Technical Field

[0001] This invention belongs to the fields of materials synthesis, energy and environmental protection technology, and in particular relates to a method and apparatus for recovering high-purity pyrite by enhancing the conversion of ferrous sulfate using sulfur-containing reducing gas. Background Technology

[0002] Industrial ferrous sulfate (in the form of FeSO4·7H2O or FeSO4) is a typical bulk solid waste generated in industrial processes such as titanium dioxide production and steel pickling. Global annual production exceeds 30 million tons, of which approximately 5.7 million tons of sulfur resources are not effectively recovered, resulting in significant resource waste and environmental pressure. This solid waste contains impurities such as manganese and magnesium and is hygroscopic, severely limiting its economic viability for resource utilization. Existing disposal and recycling pathways have significant shortcomings: landfill disposal easily leads to heavy metal pollution of soil, posing a prominent environmental risk; even when used to prepare low-end water purification agents or fertilizers such as ferric ammonium sulfate, the added value is less than 800 yuan / ton, making it difficult to cover the various costs in the treatment process, resulting in low commercial viability. More importantly, the sulfate ions (SO4) in ferrous sulfate... 2- Sulfate accounts for over 19% of its mass, and the recovery of its sulfur resources has long relied on high-temperature pyrolysis processes. Taking the traditional fluidized bed decomposition method as an example, this process requires converting sulfate ions into SO2 at high temperatures of 750-850℃ (reaction formula: FeSO4 → Fe2O3 + SO2 + O2), with energy consumption exceeding 1000 kWh per ton of material, and a sulfur recovery rate of only 60-70%. The high-temperature environment not only exacerbates equipment corrosion and extends its service life, but the generated SO2 gas also requires a dedicated desulfurization system for treatment, further increasing the overall processing cost and limiting the large-scale application of this process.

[0003] The core components of pyrite include pyrite (a key raw material for industrial sulfuric acid production) and pyrrhotite (commonly used in adsorption). However, natural pyrite generally suffers from low purity and high impurity content, making it difficult to directly meet the needs of high-end applications. Existing related resource utilization technologies also have significant limitations: for example, patent CN102923790A uses sulfur powder and iron oxide for a solid-phase reaction, requiring a reaction temperature of 280℃ and solvents such as oleylamine, oleic acid, and alkylmethyl ammonium bromide. An additional separation process is also required after the reaction, making the process complex. Patent CN104164557A uses pyrite and limonite as raw materials, roasting them at 550-800℃ under anaerobic conditions to prepare related materials. The product is mainly pyrrhotite, but still contains many impurities. None of the above technologies effectively utilize the sulfate sulfur atoms inherent in ferrous sulfate itself; instead, they require the additional purchase of sulfur raw materials, failing to achieve deep resource utilization of solid waste and unable to solve the disposal problem of ferrous sulfate solid waste.

[0004] Meanwhile, the resource utilization of sulfur-containing waste gases (such as H2S and COS) also faces challenges related to high temperatures and low added value. Currently, the mainstream treatment process still involves converting these waste gases into sulfur. This process is not only energy-intensive and requires large-scale equipment investment, but also produces products with low added value, failing to achieve high-value utilization of sulfur-containing waste gases. Therefore, addressing industry pain points such as the difficulties in disposing of ferrous sulfate solid waste, insufficient quality of pyrite resources, and the lack of high-value utilization pathways for sulfur-containing waste gases, developing synergistic technologies that can address these issues is of significant practical importance for promoting the development of a circular economy. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art by providing a method and apparatus for enhancing the conversion and recovery of high-purity pyrite using sulfur-containing reducing gas.

[0006] The objective of this invention can be achieved through the following technical solutions: A method for recovering high-purity pyrite by enhancing the conversion of ferrous sulfate using sulfur-containing reducing gas includes the following steps: S1. Pretreatment: Inert gas is introduced into the reaction system to heat and dehydrate the ferrous sulfate solid material; S2, Sulfation reaction: A mixed gas containing sulfur-containing reducing gas and carrier gas is passed into a reactor containing the ferrous sulfate solid material to carry out the reaction; S3. Post-processing: The solid products after the reaction are washed with water and dried to obtain high-purity pyrite, and SO2 in the reaction tail gas is recovered and utilized.

[0007] Further, in step S1, the heating and dehydration temperature is 350~450℃; the inert gas is nitrogen; the nitrogen replacement time before pretreatment is 30~60min; the nitrogen flow rate to the mass hourly space velocity ratio of the ferrous sulfate solid material during pretreatment is 2000~4000mL / (g·h), preferably 3000mL / (g·h).

[0008] Further, in step S2, the carrier gas is an inert gas, preferably nitrogen; the sulfur-containing reducing gas is hydrogen sulfide (H2S) or carbonyl sulfide (COS); and the volume concentration of the sulfur-containing reducing gas in the mixed gas is 5-20%.

[0009] Furthermore, in step S2, the mixed gas also contains a reducing accelerator.

[0010] Furthermore, the reducing accelerator is hydrogen (H2) or carbon monoxide (CO); the volume concentration of the reducing accelerator in the mixed gas is 2-10%.

[0011] Furthermore, the volume ratio of the reducing accelerator to the sulfur-containing reducing gas is 0.5 to 2:1.

[0012] Furthermore, in step S2, the mass hourly space velocity ratio of the total mixed gas volume to the ferrous sulfate solid material during the reaction is 3000~6000 mL / (g·h); the sulfidation reaction is carried out at a temperature of 300~500℃.

[0013] Furthermore, in step S3, the high-purity pyrite is FeS2 or Fe7S8; The specific products of the high-purity pyrite used vary depending on the reaction raw materials: When hydrogen sulfide is used as a reactant, the high-purity pyrite product generated is FeS2, and the corresponding main reaction formula is as follows: FeSO4 + 2H2S → FeS2 + SO2 + 2H2O; When carbonyl sulfide is used as the reaction raw material, the high-purity pyrite product generated is Fe7S8, and the corresponding main reaction formula is as follows: 7FeSO4+10COS→Fe7S8+9SO2+10CO2; The purity of the high-purity pyrite is ≥99%; the volume concentration of the recovered SO2 gas is 3~8%.

[0014] This invention provides an apparatus for implementing the method of recovering high-purity pyrite by enhancing the conversion of ferrous sulfate using sulfur-containing reducing gas as described in any of the preceding claims, comprising: At least one storage unit for storing gaseous raw materials; the gaseous raw materials include sulfur-containing reducing gas, reducing accelerator and inert gas; A fixed-bed reactor, wherein the gas inlet of the fixed-bed reactor is connected to the storage unit, and the interior is loaded with ferrous sulfate raw material to provide reaction space for the sulfidation reaction of ferrous sulfate and gaseous raw material; A temperature-controlled reactor, inside which the fixed-bed reactor is disposed, is used for heating and temperature control of the fixed-bed reactor; A water washing unit and a vacuum drying unit are connected in sequence. The feed end of the water washing unit is connected to the solid product outlet of the fixed bed reactor and is used to purify the solid product after sulfidation. The vacuum drying unit is used to dry the purified solid product. The tail gas recovery unit is connected to the gas outlet of the fixed-bed reactor and is used to recover SO2 gas generated during the reaction process. This tail gas recovery unit is either an SO2 absorption tower or an SO2 condenser.

[0015] Furthermore, it also includes a gas mixing tank, which is located between the storage unit and the fixed bed reactor, for mixing the gas delivered from the storage unit in a set ratio before delivering it to the fixed bed reactor.

[0016] The gas mixing tank is equipped with a mass flow controller (MFC) for precise control of the gas mixing ratio.

[0017] Compared with the prior art, the present invention has the following beneficial effects: (1) This invention promotes the release of sulfur dioxide in sulfate ions through the reduction of sulfur-containing reducing gas (H2S or COS) and synthesizes pyrite FeS2 and Fe7S8. FeS2 can be directly used in the sulfuric acid preparation industry, and Fe7S8 has excellent adsorption performance and can be used as an adsorption material to expand application scenarios.

[0018] In addition, the present invention can also add a reducing accelerator (H2 or CO) to utilize the synergistic effect of the accelerator and the sulfur-containing reducing gas: the sulfur-containing reducing gas can promote electron transfer in the sulfur form conversion process. At the same time, H2 or CO can react with the active sulfur intermediates to be converted back into sulfur-containing reducing gas, avoiding the conversion of active sulfur into sulfur by-products during the reaction process, accelerating the release of SO2 in sulfate, promoting the sulfidation reaction to proceed in a directional manner, and greatly improving the reaction rate and raw material conversion rate. This invention enables efficient recovery of sulfur from ferrous sulfate and synthesis of pyrite at a relatively low temperature of 300~500℃, which significantly reduces energy consumption and equipment high-temperature resistance requirements compared to the traditional high-temperature conversion process of 750~850℃. (2) This invention uses ferrous sulfate, a byproduct accumulated in large quantities in the chemical industry, as raw material to transform it from environmental waste into high-value-added pyrite products. This not only solves the problems of land occupation and environmental pollution caused by the accumulation of ferrous sulfate, but also provides a new path for the resource utilization of industrial byproducts, which is in line with the concept of green development. This invention is conducive to the high-value resource utilization of ferrous sulfate, a byproduct in the chemical industry, while realizing the efficient preparation of pyrite. The SO2 generated during the reaction process of this invention is efficiently recovered by the tail gas recovery unit, avoiding the waste of sulfur resources and forming a sulfur resource recycling chain of "ferrous sulfate → pyrite + SO2 → downstream high-value products", which significantly improves the comprehensive utilization value of sulfur. In summary, this invention effectively solves the problems of high pyrolysis reaction temperature and difficulty in purification and impurity removal in the recovery process of ferrous sulfate resources, reduces the reaction conversion temperature, accelerates the reaction rate, and improves the purity of pyrite products and the concentration of SO2 product gas, thereby significantly improving the comprehensive utilization performance of ferrous sulfate.

[0019] (3) The device used in this invention has a simple structure, is easy to operate, has low operating costs, is easy to achieve large-scale continuous production, and has significant industrial application prospects. Attached Figure Description

[0020] Figure 1 This is a structural block diagram of the apparatus used in this invention to implement a method for enhancing the conversion and recovery of high-purity pyrite using sulfur-containing reducing gas; The numbers in the diagram are as follows: 1-First storage unit, 2-Second storage unit, 3-Third storage unit, 4-Gas mixing tank, 5-Temperature-controlled reactor, 6-Fixed bed reactor, 7-Water washing unit, 8-Vacuum drying unit, 9-Solid product, 10-Tail gas, 11-Tail gas recovery unit; MFC-Mass flow controller. Figure 2 The image shown is the XRD pattern of the synthesized sample from Example 1 of this invention. Figure 3 The image shown is the XRD pattern of the synthesized sample from Example 6 of this invention. Detailed Implementation

[0021] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0022] In the following embodiments, unless otherwise specified, the raw materials or processing techniques are conventional commercially available raw materials or conventional processing techniques in the art. Unless otherwise specified, the functional components or structures are conventional components or conventional structures used in the art to achieve the corresponding functions.

[0023] This invention utilizes ferrous sulfate, a byproduct of the chemical industry, as a raw material, transforming it from environmental waste into high-value-added pyrite. It employs sulfur-containing waste gas (such as H2S and COS) as a reducing agent to react with bulk solid waste ferrous sulfate generated during titanium dioxide production and steel pickling processes, producing FeS2 and Fe7S8 products respectively. The generated SO2 tail gas is then comprehensively recovered in a recycling unit. This effectively solves the problems of high pyrolysis reaction temperature and difficult purification in the recovery of pyrite resources from ferrous sulfate. By introducing sulfur-containing reducing gas, using ferrous iron as the active site, active sulfur species are activated, thereby activating sulfate ions and promoting oxygen dissociation, lowering the reaction conversion temperature and accelerating the reaction rate. The reaction is protected by inert gas, and hydrogen and carbon monoxide are added as promoters, improving the purity of the pyrite product and significantly enhancing the comprehensive utilization performance of ferrous sulfate. The invention also relates to an apparatus for realizing the method of enhancing the conversion and recovery of high-purity pyrite from ferrous sulfate using sulfur-containing reducing gas, such as… Figure 1As shown, it includes: three storage units, a gas mixing tank 4, a temperature-controlled reactor 5, a fixed-bed reactor 6, a water washing unit 7, a vacuum drying unit 8, and a tail gas recovery unit 11.

[0024] The three storage units are designated as first storage unit 1, second storage unit 2, and third storage unit 3, which store sulfur-containing reducing gas, reducing accelerator, and nitrogen, respectively. A gas mixing tank 4 is connected between each storage unit and the fixed-bed reactor 6, used to mix the gases delivered from each storage unit according to a set ratio and then deliver the mixed gas to the fixed-bed reactor 6. The gas mixing tank 4 is equipped with a mass flow controller (MFC) for precise control of the gas mixing ratio. The fixed-bed reactor 6 is loaded with ferrous sulfate raw material to provide reaction space for the sulfidation reaction between ferrous sulfate and the gaseous raw material. The fixed-bed reactor 6 is located inside a temperature-controlled reactor 5, which is used for heating and temperature control of the fixed-bed reactor 6.

[0025] The feed end of the water washing unit 7 is connected to the solid product outlet of the fixed bed reactor 6, and is used to purify the sulfided solid product; the feed end of the vacuum drying unit 8 is connected to the discharge end of the water washing unit 7, and is used to dry the purified solid product.

[0026] The tail gas recovery unit 11 is connected to the gas outlet of the fixed-bed reactor 6 and is used to recover the tail gas 10 generated during the reaction process. This tail gas recovery unit 11 is an SO2 absorption tower.

[0027] The following detailed description is provided through specific embodiments: Example 1 The method for recovering high-purity pyrite by enhancing the conversion of ferrous sulfate using sulfur-containing reducing gas employs the apparatus described above, and the specific steps are as follows: S1. Pretreatment: Nitrogen gas is supplied from the third storage unit 3 to the fixed-bed reactor 6 to replace the oxygen in the pipelines and reactor for 30 minutes. After replacement, the temperature-controlled reactor 5 is heated to 400℃ to remove surface moisture from the ferrous sulfate material. Throughout the pretreatment process, the nitrogen flow rate to the mass hourly space velocity (MHV) ratio of the ferrous sulfate solid material is controlled at 3000 mL / (g·h).

[0028] S2. Sulfation Reaction: H2S and nitrogen are transported to gas mixing tank 4 from the first storage unit 1 and the third storage unit 3, respectively, to obtain a mixed gas, wherein the volume concentration of H2S is 10%. Subsequently, the mixed gas is transported to fixed-bed reactor 6 to undergo a sulfation reaction with ferrous sulfate. Fixed-bed reactor 6 is a quartz tube reactor, with both ends sealed by stainless steel joints; the mass hourly space velocity ratio of the total mixed gas volume to the ferrous sulfate solid material is 3000 mL / (g·h), and the reaction temperature is maintained at 400℃.

[0029] S3. After 2 hours of reaction, no more SO2 gas was detected in the outlet section, and the reaction was stopped. The solid reaction product was sent to the water washing unit 7 to remove impurities, and then dried in the vacuum drying unit 8 to finally obtain a high-purity solid product 9 (FeS2) with a purity ≥99%. The tail gas 10 generated during the reaction (mainly SO2) was fed into the tail gas recovery unit 11 for recovery, and the volume concentration of the recovered SO2 gas was 6%. Figure 2 The XRD pattern of the synthesized solid product is shown. The pattern matches the standard characteristic peaks of FeS2 perfectly, confirming that the product is the target FeS2.

[0030] Example 2 The apparatus and method used in this embodiment are basically the same as those in Embodiment 1, except that: H2S, H2 and nitrogen are respectively transported to the gas mixing tank 4 by the first storage unit 1, the second storage unit 2 and the third storage unit 3 to obtain a mixed gas, wherein the volume concentration of H2S is 10% and the volume concentration of H2 is 5%.

[0031] After 1 hour of reaction, sulfur dioxide was no longer detected in the outlet section, and the reaction was stopped.

[0032] The final product FeS2, a high-purity solid, was obtained with a purity of ≥99%; the volume concentration of the recovered SO2 gas was 7%.

[0033] Example 3 The apparatus and method used in this embodiment are basically the same as those in Embodiment 1, except that: H2S, H2 and nitrogen are respectively transported to the gas mixing tank 4 by the first storage unit 1, the second storage unit 2 and the third storage unit 3 to obtain a mixed gas, wherein the volume concentration of H2S is 10% and the volume concentration of H2 is 10%.

[0034] After 45 minutes of reaction, sulfur dioxide was no longer detected in the outlet section, and the reaction was stopped.

[0035] The final product FeS2, a high-purity solid, was obtained with a purity of ≥99%; the volume concentration of the recovered SO2 gas was 8%.

[0036] Example 4 The apparatus and method used in this embodiment are basically the same as those in Embodiment 1, except that: H2S, H2 and nitrogen are respectively transported to the gas mixing tank 4 by the first storage unit 1, the second storage unit 2 and the third storage unit 3 to obtain a mixed gas, wherein the volume concentration of H2S is 10% and the volume concentration of H2 is 5%; the sulfidation reaction temperature is set to 300℃.

[0037] After 2 hours of reaction, sulfur dioxide was no longer detected in the outlet section, and the reaction was stopped.

[0038] The final product FeS2, a high-purity solid, was obtained with a purity of ≥99%; the volume concentration of the recovered SO2 gas was 6%.

[0039] Example 5 The apparatus and method used in this embodiment are basically the same as those in Embodiment 1, except that: H2S, H2 and nitrogen are respectively transported to the gas mixing tank 4 by the first storage unit 1, the second storage unit 2 and the third storage unit 3 to obtain a mixed gas, wherein the volume concentration of H2S is 10% and the volume concentration of H2 is 5%; the sulfidation reaction temperature is set to 500℃.

[0040] After 50 minutes of reaction, sulfur dioxide was no longer detected in the outlet section, and the reaction was stopped.

[0041] The final product FeS2, a high-purity solid, was obtained with a purity of ≥99%; the volume concentration of the recovered SO2 gas was 7%.

[0042] Example 6 The apparatus and method used in this embodiment are basically the same as those in Embodiment 1, except that: COS and nitrogen are respectively transported to the gas mixing tank 4 by the first storage unit 1 and the third storage unit 3 to obtain a mixed gas, wherein the volume concentration of COS is 10%.

[0043] After 2 hours of reaction, sulfur dioxide was no longer detected in the outlet section, and the reaction was stopped.

[0044] The final product Fe7S8 is a high-purity solid with a purity of ≥99%; the volume concentration of the recovered SO2 gas is 5%. Figure 3 The XRD pattern of the synthesized solid product is shown. The pattern matches the standard characteristic peaks of Fe7S8 perfectly, confirming that the product is the target Fe7S8.

[0045] Example 7 The apparatus and method used in this embodiment are basically the same as those in Embodiment 1, except that: COS, CO and nitrogen are respectively transported to the gas mixing tank 4 by the first storage unit 1, the second storage unit 2 and the third storage unit 3 to obtain a mixed gas, wherein the volume concentration of COS is 10% and the volume concentration of CO is 5%.

[0046] After 2 hours of reaction, sulfur dioxide was no longer detected in the outlet section, and the reaction was stopped.

[0047] The final product Fe7S8 is a high-purity solid with a purity of ≥99%; the volume concentration of the recovered SO2 gas is 6%.

[0048] Example 8 The apparatus and method used in this embodiment are basically the same as those in Embodiment 1, except that: COS, CO and nitrogen are respectively transported to the gas mixing tank 4 by the first storage unit 1, the second storage unit 2 and the third storage unit 3 to obtain a mixed gas, wherein the volume concentration of COS is 10% and the volume concentration of CO is 10%.

[0049] After 1.5 hours of reaction, sulfur dioxide was no longer detected in the outlet section, and the reaction was stopped.

[0050] The final product Fe7S8 is a high-purity solid with a purity of ≥99%; the volume concentration of the recovered SO2 gas is 8%.

[0051] Example 9 The apparatus and method used in this embodiment are basically the same as those in Embodiment 1, except that: COS, CO and nitrogen are transported to the gas mixing tank 4 by the first storage unit 1, the second storage unit 2 and the third storage unit 3 respectively to obtain a mixed gas, wherein the volume concentration of COS is 10% and the volume concentration of CO is 5%; the reaction temperature is set to 500℃.

[0052] After 1.2 hours of reaction, sulfur dioxide was no longer detected in the outlet section, and the reaction was stopped.

[0053] The final product Fe7S8 is a high-purity solid with a purity of ≥99%; the volume concentration of the recovered SO2 gas is 7%.

[0054] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A method for recovering high-purity pyrite by enhancing the conversion of ferrous sulfate using sulfur-containing reducing gas, characterized in that, Includes the following steps: S1. Pretreatment: Inert gas is introduced into the reaction system to heat and dehydrate the ferrous sulfate solid material; S2, Sulfidation reaction: A mixed gas containing sulfur-containing reducing gas and carrier gas is passed into a reactor containing pretreated ferrous sulfate solid material to carry out the reaction. S3. Post-processing: The solid products after the reaction are washed with water and dried to obtain high-purity pyrite, and SO2 in the reaction tail gas is recovered and utilized.

2. The method for recovering high-purity pyrite by enhancing the conversion of ferrous sulfate using sulfur-containing reducing gas according to claim 1, characterized in that, In step S1, the temperature for heating and dehydration is 350~450℃.

3. The method for recovering high-purity pyrite by enhancing the conversion of ferrous sulfate using sulfur-containing reducing gas according to claim 1, characterized in that, In step S2, the carrier gas is an inert gas; the sulfur-containing reducing gas is hydrogen sulfide or carbonyl sulfide; and the volume concentration of the sulfur-containing reducing gas in the mixed gas is 5-20%.

4. The method for recovering high-purity pyrite by enhancing the conversion of ferrous sulfate using sulfur-containing reducing gas according to claim 1, characterized in that, In step S2, the mixed gas also contains a reducing accelerator.

5. The method for recovering high-purity pyrite by enhancing the conversion of ferrous sulfate using sulfur-containing reducing gas according to claim 4, characterized in that, The reducing accelerator is hydrogen or carbon monoxide; the volume concentration of the reducing accelerator in the mixed gas is 2-10%.

6. The method for recovering high-purity pyrite by enhancing the conversion of ferrous sulfate using sulfur-containing reducing gas according to claim 5, characterized in that, The volume ratio of the reducing accelerator to the sulfur-containing reducing gas is 0.5~2:

1.

7. The method for recovering high-purity pyrite by enhancing the conversion of ferrous sulfate using sulfur-containing reducing gas according to claim 1, characterized in that, In step S2, the mass hourly space velocity ratio of the total mixed gas volume to the ferrous sulfate solid material during the reaction is 3000~6000 mL / (g·h); the sulfidation reaction is carried out at a temperature of 300~500℃.

8. The method for recovering high-purity pyrite by enhancing the conversion of ferrous sulfate using sulfur-containing reducing gas according to claim 1, characterized in that, In step S3, the high-purity pyrite is FeS2 or Fe7S8.

9. An apparatus for implementing the method of recovering high-purity pyrite by enhancing the conversion of ferrous sulfate with sulfur-containing reducing gas as described in any one of claims 1 to 8, characterized in that, include: At least one storage unit for storing gaseous raw materials; A fixed-bed reactor, wherein the gas inlet of the fixed-bed reactor is connected to the storage unit, and the interior is loaded with ferrous sulfate raw material to provide reaction space for the sulfidation reaction of ferrous sulfate and gaseous raw material; A temperature-controlled reactor, inside which the fixed-bed reactor is disposed, is used for heating and temperature control of the fixed-bed reactor; A water washing unit and a vacuum drying unit are connected in sequence. The feed end of the water washing unit is connected to the solid product outlet of the fixed bed reactor and is used to purify the solid product after sulfidation. The vacuum drying unit is used to dry the purified solid product. The tail gas recovery unit is connected to the gas outlet of the fixed-bed reactor and is used to recover SO2 gas generated during the reaction process.

10. The apparatus according to claim 9, characterized in that, It also includes a gas mixing tank, which is located between the storage unit and the fixed bed reactor, and is used to mix the gas delivered from the storage unit in a set ratio before delivering it to the fixed bed reactor.

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