System and method for fluidized roasting of high-sulfur arsenic carbon refractory gold concentrate

Abstract

The application provides a high-sulfur arsenic carbon refractory gold concentrate boiling roasting system and method, and belongs to the technical field of mineral processing and metallurgy. The system comprises a four-furnace boiling roasting device and a flue gas recovery device. The four-furnace boiling roasting device comprises four furnaces connected in sequence and with decreasing horizontal heights. The bottoms of the four furnaces are respectively provided with four air chambers in communication with the furnaces. The first and fourth air chambers only pass in air, the second air chamber only passes in flue gas generated in the first furnace, and the third air chamber only passes in flue gas generated in the fourth furnace. The flue gas of the second and third furnaces is passed into the flue gas recovery device, which comprises a high-temperature carbon bed reactor, a realgar recovery device, a medium-temperature carbon bed reactor and a sulfur recovery device connected in sequence. The application reasonably designs the process and the equipment to recover sulfur and arsenic in the ore in the form of sulfur and realgar, has a small amount of flue gas emission, is beneficial to environmental protection, and is beneficial to improving the gold leaching rate of the refractory gold concentrate.

Description

Technical Field

[0001] This application relates to the fields of mineral processing and metallurgical technology, specifically to a fluidized bed roasting system and method for high-sulfur, arsenic, and carbon refractory gold concentrate. Background Technology

[0002] High-sulfur, arsenic, and carbon refractory gold concentrate refers to gold concentrate containing more than 30% sulfur, and with high arsenic and carbon (organic carbon and graphitic carbon) content. In the field of metallurgical technology, the gold recovery rate of refractory gold concentrate directly subjected to cyanidation without pretreatment is very low, especially for high-sulfur, arsenic, and carbon refractory gold concentrate, where the gold recovery rate approaches zero. Therefore, pretreatment of refractory gold concentrate is necessary before using leaching to improve the gold leaching recovery rate. Currently, commonly used pretreatment processes mainly include biological oxidation, pressure oxidation, and roasting oxidation.

[0003] Biological oxidation is a method for pretreating gold concentrate using the oxidation of microorganisms. During this pretreatment, sulfides and arsenopyrite in the gold concentrate are oxidized into sulfuric acid and its salts, and arsenic acid and its salts. However, this method has several problems when applied to the pretreatment of high-sulfur, arsenic, and carbon refractory gold concentrates: First, biological oxidation cannot solve the problem of carbonaceous material "gold robbery," and the excessively low pH environment caused by the large amount of sulfuric acid produced and the toxic effects of arsenic on the oxidizing bacteria severely affect the biological oxidation effect. Second, the biological oxidation liquid for high-sulfur, arsenic, and carbon gold concentrates is a strongly acidic sulfuric acid solution containing arsenic and iron. Its treatment requires a large amount of lime and produces a large amount of neutralization slag (arsenic-containing solid waste), making it difficult to economically and rationally recover sulfur, arsenic, and iron components, and resulting in high wastewater treatment costs. Third, adopting low-concentration slurry biological oxidation, or thickening and dewatering after the first stage of biological oxidation followed by rehydration and slurry preparation for the second stage of biological oxidation, can improve the biological oxidation effect, but it also leads to a significant increase in equipment investment.

[0004] Pressure oxidation refers to the oxidative pretreatment of gold concentrate under certain pressure conditions. When applied to the pretreatment of refractory gold concentrates containing high sulfur, arsenic, and carbon, the following problems exist: First, pressure oxidation also fails to eliminate the "gold robbery" problem caused by carbonaceous materials, thus affecting the gold leaching rate. Second, pressure oxidation also produces strongly acidic oxidizing liquids containing arsenic and iron, making it difficult to economically and reasonably recover sulfur, arsenic, and iron components, and the waste liquid treatment cost is also high. Third, when pressure oxidizing high sulfur, arsenic, and carbon gold concentrates, controlling the oxygen partial pressure can generate sulfur, but this sulfur contains arsenic, making it difficult to produce commercially viable sulfur products with acceptable arsenic content.

[0005] Roasting oxidation is a pretreatment method that uses high-temperature roasting to oxidize substances in gold concentrate. Commonly used equipment includes rotary kilns, multi-hearth furnaces, and fluidized bed furnaces. For example, Chinese patent CN201262515Y discloses a two-stage fluidized bed roasting furnace for arsenic-containing gold concentrate, connecting two fluidized bed furnaces in series for complete oxidation roasting. Roasting oxidation can remove "gold-stealing carbon" through oxidation, effectively solving the problem of carbonaceous "gold-stealing." However, there are also some problems with using traditional roasting methods to treat high-sulfur arsenic-carbon gold concentrate. First, the reaction heat of traditional roasting of high-sulfur arsenic-carbon gold concentrate is very high, which can easily lead to excessively high roasting temperatures, resulting in over-burning and affecting the gold leaching rate of the roasted ore. In traditional roasting oxidation, the oxidative roasting reaction requires an excess of oxygen (10-20% excess air) to ensure complete oxidation of pyrite, arsenopyrite, and carbon in the gold concentrate. The main reaction equations and their enthalpies at 650℃ during the roasting process are as follows:

[0006] FeS2+2.75O2=0.5Fe2O3+2SO2 △H1=-824.3kJ

[0007] FeAsS+2.5O2=0.5Fe2O3+0.5As2O3+SO2 △H2=-1781.7kJ

[0008] C + O₂ = CO₂ ΔH₃ = -394.5 kJ

[0009] As can be seen, the heat released during the traditional roasting oxidation process is very large. Even if the gold concentrate is fed into the roasting furnace in the form of a slurry, and the furnace temperature is reduced by absorbing heat through the evaporation of water in the slurry or by using cooling wall heat dissipation techniques, the furnace temperature can still reach above 800℃-900℃. Secondly, during the traditional roasting process, sulfur and arsenic in the gold concentrate are oxidized to generate a large amount of SO2 and As2O3, which enter the flue gas. After dust removal and condensation to recover As2O3, sulfuric acid is prepared. However, this sulfuric acid contains excessive arsenic, which limits its market. Moreover, most roasting and gold extraction workshops are located in remote mountainous areas, and the storage and transportation costs make it even more difficult to sell this sulfuric acid. Thirdly, the As2O3 produced by the traditional roasting method is commonly known as arsenic trioxide, which is a highly toxic compound. Even if it is recovered, it involves environmental and safety issues and is subject to strict control.

[0010] In summary, traditional pretreatment processes for high-sulfur, arsenic, and carbon refractory gold concentrates are insufficient to achieve high gold leaching rates. Furthermore, the pretreatment generates significant amounts of flue gas, and the byproducts from this flue gas treatment offer limited added value. Additionally, the substantial amounts of sulfur and arsenic in the ore cannot be effectively recovered. Therefore, it is necessary to improve the pretreatment technology and equipment based on the characteristics of high-sulfur, arsenic, and carbon refractory gold concentrates, and to develop a fluidized bed roasting system and method for recovering sulfur and arsenic from high-sulfur, arsenic, and carbon refractory gold concentrates using sulfur and realgar. Summary of the Invention

[0011] In view of the technical problems existing in the background art, this application provides a fluidized bed roasting system and method for high-sulfur, arsenic and carbon refractory gold concentrate, which aims to solve the technical problems of low gold leaching rate, large amount of flue gas generated during the pretreatment of high-sulfur, arsenic and carbon refractory gold concentrate, the by-products generated from the flue gas treatment are difficult to provide high added value, and the large amount of sulfur and arsenic in the ore cannot be well recovered and utilized.

[0012] In a first aspect, embodiments of this application provide a fluidized bed roasting system for high-sulfur, arsenic, and carbon refractory gold concentrate.

[0013] In the technical solution of this application embodiment, the fluidized bed roasting system for high-sulfur, arsenic, and carbon refractory gold concentrate includes a four-furnace fluidized bed roasting device and a flue gas recovery device; wherein, the four-furnace fluidized bed roasting device includes a first furnace, a second furnace, a third furnace, and a fourth furnace connected in sequence and decreasing in horizontal height, and the bottom of the four furnaces is respectively provided with a first air chamber, a second air chamber, a third air chamber, and a fourth air chamber communicating with the furnace;

[0014] The first air chamber is provided with a first air inlet pipe on its side wall, and the first air inlet pipe is connected to a first blower; specifically, the air inlet end of the first air inlet pipe is connected to the air outlet of the first blower to introduce air into the first air chamber.

[0015] The second air inlet pipe is provided on the side wall of the second air chamber. The second air inlet pipe is sequentially connected to the third induced draft blower, the first cyclone dust collector, and the top of the first furnace. Specifically, the air inlet end of the second air inlet pipe is connected to the air outlet of the third induced draft blower, the air inlet of the third induced draft blower is connected to the exhaust port of the first cyclone dust collector, and the air inlet of the first cyclone dust collector is connected to the top of the first furnace, so as to introduce the flue gas generated in the reaction in the first furnace into the second air chamber.

[0016] A third air inlet pipe is provided on the side wall of the third air chamber. The third air inlet pipe is sequentially connected to the fourth induced draft blower, the fourth cyclone dust collector, and the top of the fourth furnace. Specifically, the air inlet end of the third air inlet pipe is connected to the air outlet of the fourth induced draft blower, the air inlet of the fourth induced draft blower is connected to the exhaust outlet of the fourth cyclone dust collector, and the air inlet of the fourth cyclone dust collector is connected to the top of the fourth furnace, so as to introduce the flue gas generated in the reaction in the fourth furnace into the third air chamber.

[0017] The fourth air chamber is provided with a fourth air inlet pipe on its side wall, and the fourth air inlet pipe is connected to the second blower; specifically, the air inlet end of the fourth air inlet pipe is connected to the air outlet of the second blower to introduce air into the fourth air chamber.

[0018] The flue gas recovery device includes a high-temperature carbon bed reactor, a realgar recovery unit, a medium-temperature carbon bed reactor, and a sulfur recovery unit connected in sequence to react SO2 and As2O3 in the flue gas and recover realgar and sulfur in steps.

[0019] In some embodiments, the top of the second furnace is connected to the flue gas recovery device via a second cyclone dust collector, a first induced draft blower, and a first bag filter connected in sequence; specifically, the top of the second furnace is connected to the air inlet of the second cyclone dust collector, the exhaust port of the second cyclone dust collector is connected to the air inlet of the first induced draft blower, the air outlet of the first induced draft blower is connected to the air inlet of the first bag filter, and the exhaust port at the top of the first bag filter is connected to the high-temperature carbon bed reactor of the flue gas recovery device B;

[0020] The top of the third furnace is connected to the high-temperature carbon bed reactor of the flue gas recovery device via a third cyclone dust collector, a second induced draft blower, and a second bag filter connected in sequence. Specifically, the top of the third furnace is connected to the air inlet of the third cyclone dust collector, the exhaust port of the third cyclone dust collector is connected to the air inlet of the second induced draft blower, the exhaust port of the second induced draft blower is connected to the air inlet of the second bag filter, and the exhaust port at the top of the second bag filter is connected to the high-temperature carbon bed reactor of the flue gas recovery device B.

[0021] The bottoms of the first bag filter and the second bag filter are respectively connected to the flue gas feed pipe located on the side wall of the fourth furnace.

[0022] In some embodiments, the flue gas recovery device further includes a heat exchanger, a flue gas purifier, a fifth induced draft blower, and a flue gas exhaust device connected in sequence with the sulfur recovery unit.

[0023] In some embodiments, the first furnace chamber and the second furnace chamber, the second furnace chamber and the third furnace chamber, and the third furnace chamber and the fourth furnace chamber are all separated by heat-resistant steel plates.

[0024] In some embodiments, the first furnace is provided with a feed inlet on its side wall, the third furnace is provided with a pulverized coal replenishment pipe on its side wall, and the fourth furnace is provided with a roasted sand outlet on its side wall.

[0025] In some embodiments, the cone and dust pipe of the first cyclone dust collector extend into the interior of the second furnace chamber, the cone and dust pipe of the second cyclone dust collector extend into the interior of the third furnace chamber, the cone and dust pipe of the third cyclone dust collector extend into the interior of the fourth furnace chamber, and the dust pipe of the fourth cyclone dust collector is located near the outlet of the roasted sand.

[0026] In some embodiments, the upper part of all cyclone dust collectors, all induced draft blowers, all bag filters, all carbon bed reactors, and the flue gas ducts connecting the components in the fluidized bed roasting system for high-sulfur, arsenic, and carbon refractory gold concentrate are all wrapped with thermal insulation material.

[0027] Secondly, this application also provides a method for boiling roasting high-sulfur, arsenic, and carbon refractory gold concentrate based on the boiling roasting system for high-sulfur, arsenic, and carbon refractory gold concentrate described in any of the foregoing schemes, comprising the following steps:

[0028] S1, high-sulfur, arsenic, and carbon refractory gold concentrate is fed into the first furnace, and air is introduced into the first air chamber to raise the temperature and react. Subsequently, the roasted ore flows into the second furnace, while only the flue gas generated in the first furnace is introduced into the second air chamber to continue the reaction. Next, the ore that has undergone secondary roasting flows into the third furnace, while only the flue gas generated in the fourth furnace is introduced into the third air chamber to continue the reaction. During the reaction, a carbon source is added to the third furnace. Finally, the ore that has undergone tertiary roasting flows into the fourth furnace, and air is introduced into the fourth air chamber to continue the reaction. After the reaction is completed, the roasted ore is discharged.

[0029] S2, the flue gas generated in the second and third furnaces is treated by two dust removal processes before entering the flue gas recovery device. First, it is passed into the high-temperature carbon bed reactor to remove most of the SO2 and all of the As2O3 through reaction. Then, it is passed into the realgar recovery unit to recover the realgar in the flue gas. Next, it is passed into the medium-temperature carbon bed reactor to further remove the residual SO2 through reaction. Then, it is passed into the sulfur recovery unit to recover sulfur. Then, it is passed into the heat exchanger for cooling and dehydration. Finally, the remaining flue gas is passed into the flue gas purifier for neutralization with lime milk or alkaline solution. Finally, it is discharged into the atmosphere through the fifth induced draft blower and the flue gas emission device.

[0030] In some embodiments, in step S1, the reaction temperature in all four furnaces is maintained between 650-680°C; in step S2, the reaction temperature in the high-temperature carbon bed reactor is higher than 570°C, the realgar recovery unit uses a condensation method to recover realgar at a temperature of 480°C-520°C, the reaction temperature in the medium-temperature carbon bed reactor is higher than 450°C, the sulfur recovery unit uses a condensation method to recover sulfur at a temperature of 200°C-280°C, and the cooling and dehydration in the heat exchanger specifically refers to cooling the flue gas to 30-50°C to remove water vapor, and recycling the resulting condensate; the carbon bed material replaced in the high-temperature carbon bed reactor and the medium-temperature carbon bed reactor is mixed into the carbon source to be fed into the third furnace, and fed into the third furnace together in step S1.

[0031] In some embodiments, the high-sulfur, arsenic, and carbon refractory gold concentrate refers to refractory gold concentrate with a sulfur content greater than or equal to 30% and an arsenic and carbon content greater than 1% respectively; the total amount of blast air required in the fluidized bed roasting method of the high-sulfur, arsenic, and carbon refractory gold concentrate accounts for 40-60% of the total amount of blast air in the conventional oxidative roasting operation.

[0032] The beneficial effects of this application are:

[0033] This application provides a fluidized bed roasting system and method for high-sulfur, arsenic, and carbon refractory gold concentrate. Based on the characteristics of this concentrate, the pretreatment process and equipment are improved, reducing the total amount of forced-air air required during pretreatment while maintaining a stable roasting temperature between 650-680℃. Simultaneously, sulfur and arsenic in the concentrate are recovered and utilized as sulfur and realgar, respectively. This not only improves the gold leaching rate but also fully utilizes resources, is environmentally friendly, and has lower processing costs. Specifically, it can be divided into the following points:

[0034] (1) The fluidized bed roasting system and method for high-sulfur arsenic carbon refractory gold concentrate provided in this application has a low calorific value during roasting, which makes it less prone to over-burning. At the same time, it can effectively solve the problem of "gold robbery" of carbon, thereby improving the gold leaching rate of roasted sand from high-sulfur arsenic carbon refractory gold concentrate.

[0035] (2) The fluidized bed roasting system and method for high-sulfur, arsenic, and carbon refractory gold concentrate provided in this application have a reasonable process flow design and corresponding fully automated equipment designed according to the process, so that sulfur and arsenic in high-sulfur, arsenic, and carbon refractory gold concentrate can be fully recovered and utilized in the form of sulfur and realgar, respectively. The recovery rate of sulfur in the final recovered product is 96.58%, the recovery rate of arsenic in realgar is 97.45%, and the purity of sulfur is greater than 99% and the purity of realgar is greater than 90%, both of which meet the sales standards and reduce the pretreatment cost to a certain extent.

[0036] (3) The fluidized bed roasting system and method for high-sulfur arsenic carbon refractory gold concentrate provided in this application requires less air volume, which is only 40-60% of the air volume required by traditional roasting methods. Therefore, the amount of flue gas emitted is also less, which is beneficial to environmental protection.

[0037] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0038] To more clearly illustrate the technical solutions of this application, the accompanying drawings used in this application will be briefly described below. Obviously, the drawings described below are merely some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without any creative effort.

[0039] Figure 1 This is a schematic diagram of the structure and process of the fluidized bed roasting system for high-sulfur, arsenic, and carbon refractory gold concentrate in the embodiments of this application;

[0040] Explanation of reference numerals in the attached drawings: A. Four-furnace fluidized bed roasting device; B. Flue gas recovery device; 1. Flue gas exhaust device; 2. Flue gas purifier; 3. Heat exchanger; 4. Sulfur recovery unit; 5. Medium-temperature carbon bed reactor; 6. Realgar recovery unit; 7. High-temperature carbon bed reactor; 8. First induced draft blower; 9. First bag filter; 10. Second bag filter; 11. Second induced draft blower; 12. First furnace; 13. First cyclone dust collector; 14. Second furnace; 15. Second cyclone dust collector; 16. Third furnace; 17. 18. Third cyclone dust collector; 19. Fourth furnace chamber; 20. Fourth cyclone dust collector; 21. Feed inlet; 22. Dust feed pipe; 23. Roasted sand outlet; 24. First air chamber; 25. First air inlet pipe; 26. Second air inlet pipe; 27. Pulverized coal supplement pipe; 28. Third air inlet pipe; 29. ​​Third air chamber; 30. Fourth air inlet pipe; 31. Fourth air chamber; 32. First blower; 33. Third induced draft blower; 34. Fourth induced draft blower; 35. Second blower; 36. Fifth induced draft blower Detailed Implementation

[0041] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0042] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0043] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0044] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0045] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0046] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0047] In the description of the embodiments of this application, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0048] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0049] High-sulfur, arsenic, and carbon refractory gold concentrate refers to gold concentrate containing more than 30% sulfur, and with high arsenic and carbon (organic carbon and graphitic carbon) content. In the field of metallurgical technology, the gold recovery rate of refractory gold concentrate directly subjected to cyanidation without pretreatment is very low, especially for high-sulfur, arsenic, and carbon refractory gold concentrate, where the gold recovery rate approaches zero. Therefore, pretreatment of refractory gold concentrate is necessary before using leaching to improve the gold leaching recovery rate. Currently, commonly used pretreatment processes mainly include biological oxidation, pressure oxidation, and roasting oxidation. However, these three processes have limitations when applied to the pretreatment of high-sulfur, arsenic, and carbon refractory gold concentrate. Not only is it difficult to achieve a high gold leaching rate, but the amount of flue gas generated during pretreatment is also large, and the by-products from the flue gas treatment are unlikely to provide high added value. Furthermore, the large amounts of sulfur and arsenic in the ore cannot be effectively recovered and utilized.

[0050] To address the aforementioned technical problems, this application provides a fluidized bed roasting system and method for high-sulfur, arsenic, and carbon refractory gold concentrate. Based on the characteristics of high-sulfur, arsenic, and carbon refractory gold concentrate, the pretreatment process technology and equipment are improved, reducing the total amount of forced draft air required in the pretreatment while maintaining a stable roasting temperature between 650-680℃. The total amount of forced draft air is only 40-60% of that in traditional oxidative roasting operations. Simultaneously, sulfur and arsenic in the high-sulfur, arsenic, and carbon refractory gold concentrate are recovered and utilized in the form of sulfur and realgar, respectively. This fluidized bed roasting system and method for high-sulfur, arsenic, and carbon refractory gold concentrate not only has low flue gas emissions and low treatment costs but also makes full use of resources and is environmentally friendly.

[0051] The following are some specific embodiments. It should be noted that the embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they shall be performed in accordance with the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially.

[0052] Example 1

[0053] Please refer to Figure 1 This application provides a fluidized bed roasting system for high-sulfur, arsenic, and carbon refractory gold concentrate. This system is a fully automated continuous production system, including a four-furnace fluidized bed roasting device A and a flue gas recovery device B.

[0054] In this embodiment, the four-furnace fluidized bed roasting apparatus A includes a first furnace 12, a second furnace 14, a third furnace 16, and a fourth furnace 18 connected sequentially and decreasing in horizontal height. Specifically, the first furnace 12 is higher than the second furnace 14, the second furnace 14 is higher than the third furnace 16, and the third furnace 16 is higher than the fourth furnace 18. Heat-resistant steel plates separate the first furnace 12 from the second furnace 14, the second furnace 14 from the third furnace 16, and the third furnace 16 from the fourth furnace 18.

[0055] The bottom of the four furnace chambers is respectively provided with a first air chamber 23, a second air chamber 26, a third air chamber 29 and a fourth air chamber 31 that are connected to the furnace chamber.

[0056] Furthermore, a first air inlet pipe 24 is provided on the side wall of the first air chamber 23, and the first air inlet pipe 24 is connected to the first blower 32. Specifically, the air inlet end of the first air inlet pipe 24 is connected to the air outlet of the first blower 32 to introduce air into the first air chamber 23.

[0057] A second air inlet pipe 25 is provided on the side wall of the second air chamber 26. The second air inlet pipe 25 is sequentially connected to the third induced draft blower 33, the first cyclone dust collector 13, and the top of the first furnace 12. Specifically, the air inlet end of the second air inlet pipe 25 is connected to the air outlet of the third induced draft blower 33, the air inlet of the third induced draft blower 33 is connected to the exhaust port of the first cyclone dust collector 13, and the air inlet of the first cyclone dust collector 13 is connected to the top of the first furnace 12. With this configuration, the flue gas generated in the reaction in the first furnace 12 can be filtered by the first cyclone dust collector 13 and then fed into the second air chamber 26 by the third induced draft blower 33, where it participates in the reaction in the second furnace 14.

[0058] A third air inlet pipe 28 is provided on the side wall of the third air chamber 29. The third air inlet pipe 28 is sequentially connected to the fourth induced draft blower 34, the fourth cyclone dust collector 19, and the top of the fourth furnace 18. Specifically, the air inlet end of the third air inlet pipe 28 is connected to the air outlet of the fourth induced draft blower 34, the air inlet of the fourth induced draft blower 34 is connected to the exhaust port of the fourth cyclone dust collector 19, and the air inlet of the fourth cyclone dust collector 19 is connected to the top of the fourth furnace 18. With this configuration, the flue gas generated in the reaction in the fourth furnace 18 can be filtered by the fourth cyclone dust collector 19 and then fed into the third air chamber 29 through the fourth induced draft blower 34, where it participates in the reaction in the third furnace 16.

[0059] A fourth air inlet pipe 30 is provided on the side wall of the fourth air chamber 31, and the fourth air inlet pipe 30 is connected to the second blower 35. Specifically, the air inlet end of the fourth air inlet pipe 30 is connected to the air outlet of the second blower 35 to introduce air into the fourth air chamber 31.

[0060] Furthermore, the first furnace 12 is provided with a feed inlet 20 on its side wall, the third furnace 16 is provided with a pulverized coal replenishment pipe 27 on its side wall, and the fourth furnace 18 is provided with a roasted sand discharge outlet 22 on its side wall.

[0061] Furthermore, the cone and dust pipe of the first cyclone dust collector 13 extend into the second furnace chamber 14, allowing the dust separated by the first cyclone dust collector 13 to fall directly into the second furnace chamber 14. The cone and dust pipe of the second cyclone dust collector 15 extend into the third furnace chamber 16, allowing the dust separated by the second cyclone dust collector 15 to fall directly into the third furnace chamber 16. The cone and dust pipe of the third cyclone dust collector 17 extend into the fourth furnace chamber 18, allowing the dust separated by the third cyclone dust collector 17 to fall directly into the fourth furnace chamber 18. The dust pipe of the fourth cyclone dust collector 19 is positioned near the calcined sand outlet 22, allowing the dust separated by the fourth cyclone dust collector 19 to fall directly into the final calcined sand.

[0062] In this embodiment, the top of the second furnace 14 is connected to the flue gas recovery device B via a second cyclone dust collector 15, a first induced draft blower 8, and a first bag filter 9 connected in sequence. Specifically, the top of the second furnace 14 is connected to the air inlet of the second cyclone dust collector 15, the exhaust port of the second cyclone dust collector 15 is connected to the air inlet of the first induced draft blower 8, the exhaust port of the first induced draft blower 8 is connected to the air inlet of the first bag filter 9, and the exhaust port at the top of the first bag filter 9 is connected to the high-temperature carbon bed reactor 7 of the flue gas recovery device B.

[0063] The top of the third furnace 16 is connected to the flue gas recovery device B via a third cyclone dust collector 17, a second induced draft blower 11, and a second bag filter 10 connected in sequence. Specifically, the top of the third furnace 16 is connected to the air inlet of the third cyclone dust collector 17, the exhaust port of the third cyclone dust collector 17 is connected to the air inlet of the second induced draft blower 11, the exhaust port of the second induced draft blower 11 is connected to the air inlet of the second bag filter 10, and the exhaust port at the top of the second bag filter 10 is connected to the high-temperature carbon bed reactor 7 of the flue gas recovery device B.

[0064] Furthermore, the bottoms of the first bag filter 9 and the second bag filter 10 are respectively connected to the dust feed pipe 21 located on the side wall of the fourth furnace 18.

[0065] With this configuration, the flue gas generated in the second furnace 14 and the third furnace 16 is purged by the second cyclone dust collector 15 and the third cyclone dust collector 17, respectively, and then conveyed to the first bag filter 9 and the second bag filter 10 for further dust removal (secondary dust removal), before being conveyed to the flue gas recovery device B for recycling. The dust removed in the first bag filter 9 and the second bag filter 10 enters the fourth furnace 18 through the dust feed pipe 21.

[0066] In this embodiment, the flue gas recovery device B includes a high-temperature carbon bed reactor 7, a realgar recovery unit 6, a medium-temperature carbon bed reactor 5, a sulfur recovery unit 4, a heat exchanger 3, a flue gas purifier 2, a fifth induced draft blower 36, and a flue gas exhaust device 1, connected in sequence. Specifically, the high-temperature carbon bed reactor 7 is connected to the realgar recovery unit 6, the realgar recovery unit 6 is connected to the medium-temperature carbon bed reactor 5, the medium-temperature carbon bed reactor 5 is connected to the sulfur recovery unit 4, the sulfur recovery unit 4 is connected to the heat exchanger 3, the heat exchanger 3 is connected to the flue gas purifier 2, the flue gas purifier 2 is connected to the fifth induced draft blower 36, and the fifth induced draft blower 36 is connected to the flue gas exhaust device 1.

[0067] With this setup, the flue gas (containing a large amount of SO2 and a small amount of As2O3) after secondary dust removal enters the high-temperature carbon bed reactor 7 from the top of the first bag filter 9 and the second bag filter 10, where it reacts to generate CO2, S, and As. The heat released by the reaction helps maintain the operating temperature (above 570℃) inside the high-temperature carbon bed reactor 7, compensating for the heat loss of the flue gas during transportation and keeping the realgar in a gaseous state. The flue gas after the reaction is transported to the realgar collector 6, which is equipped with an adjustable water spray device. The sprayed water evaporates upon encountering the high-temperature flue gas, absorbing some of the heat and causing the flue gas temperature to drop rapidly to 480℃-520℃. At this point, the realgar in the flue gas condenses into a liquid and settles to the bottom of the realgar collector 6, where it cools and crystallizes (the melting point of realgar is 267℃) and is collected.

[0068] Uncondensed components in the flue gas continue to be transported through the flue gas pipeline to the medium-temperature carbon bed reactor 5, where residual SO2 is further removed through reaction at a temperature above 450°C. The reacted flue gas is then transported to the sulfur recovery unit 4. The sulfur recovery unit 4 is also equipped with an adjustable water spray device, which can rapidly reduce the flue gas temperature to 200°C-280°C through the heat absorption of water evaporation. This causes the sulfur in the flue gas to condense into liquid and settle to the bottom of the sulfur recovery unit 4, where it cools and crystallizes (sulfur has a melting point of 112°C) and is collected.

[0069] The flue gas, after recovering realgar and sulfur, is fed into heat exchanger 3 and cooled to 30-50°C. Water vapor in the flue gas condenses in this step and is recovered for recycling. The dehydrated flue gas is then transported to flue gas purifier 2, where it is treated with lime slurry or alkaline solution to meet emission standards before being discharged through flue gas emitter 1.

[0070] In this embodiment, the upper part of all cyclone dust collectors, all induced draft blowers, bag filters, carbon bed reactors, and flue gas ducts connecting the various components in the fluidized bed roasting system for high-sulfur, arsenic, and carbon refractory gold concentrate are wrapped with thermal insulation material to prevent heat loss of flue gas and dust during transportation. Preferably, the thermal insulation material is rock wool.

[0071] In this embodiment, when the arsenic deposition in the high-temperature carbon bed reactor 7 and the medium-temperature carbon bed reactor 5 exceeds 20%, the carbon bed material is replaced, and the replaced carbon bed material is mixed into the carbon source to be fed into the third furnace 16.

[0072] This application also provides a method for fluidized bed roasting of high-sulfur, arsenic, and carbon refractory gold concentrate based on the above-mentioned fluidized bed roasting system for high-sulfur, arsenic, and carbon refractory gold concentrate, comprising the following steps:

[0073] In step S1, high-sulfur, arsenic, and carbon refractory gold concentrate is fed into the first furnace 12, and air is introduced into the first air chamber 23 to raise the temperature and initiate a reaction. Subsequently, the roasted ore flows into the second furnace 14, while only the flue gas produced in the first furnace 12 is introduced into the second air chamber 26 to continue the reaction. Next, the ore, after a second roasting, flows into the third furnace 16, while only the flue gas produced in the fourth furnace 18 is introduced into the third air chamber 29 to continue the reaction, with carbon source being added to the third furnace 16 during the process. Finally, the ore, after a third roasting, flows into the fourth furnace 18, and air is introduced into the fourth air chamber 31 to continue the reaction. After the reaction is complete, the roasted ore is discharged.

[0074] Among them, high-sulfur, arsenic, and carbon refractory gold concentrate refers to refractory gold concentrate with a sulfur content of ≥30% and an arsenic and carbon content of ≥1% respectively.

[0075] In some embodiments, in step S1, the reaction temperature in all four furnace chambers is maintained between 650-680°C.

[0076] The flue gas generated from the reactions in S2, the second furnace 14, and the third furnace 16 undergoes two dust removal processes before entering the flue gas recovery device B. First, it is passed into the high-temperature carbon bed reactor 7, where most of the SO2 and all of the As2O3 are removed through reaction at a temperature above 570℃. Then, it is passed into the realgar recovery unit 6, where realgar is recovered from the flue gas through condensation at a temperature of 480℃-520℃. Next, it is passed into the medium-temperature carbon bed reactor 5, where residual SO2 is further removed through reaction at a temperature above 450℃. Then, it is passed into the sulfur recovery unit 4, where sulfur is recovered through condensation at a temperature of 200℃-280℃. Finally, it is passed into the heat exchanger 3, where the flue gas is cooled to 30-50℃ to remove water vapor, and the resulting condensate is recycled. Finally, the remaining flue gas is passed into the flue gas purifier 2 for neutralization with lime slurry or alkaline solution, and then discharged into the atmosphere through the fifth induced draft blower 36 and the flue gas exhaust device 1.

[0077] The reaction temperature in the high-temperature carbon bed reactor 7 is controlled above 570℃ to ensure that it is higher than the boiling point of realgar (565℃), while the reaction temperature in the medium-temperature carbon bed reactor 5 is controlled above 450℃ to ensure that it is higher than the boiling point of sulfur.

[0078] The carbon bed material replaced in the high-temperature carbon bed reactor 7 and the medium-temperature carbon bed reactor 5 is mixed with the carbon source to be fed into the third furnace 16, and fed into the third furnace 16 together in step S1. Preferably, the carbon source is pulverized coal, and the feeding method is injection.

[0079] In some embodiments, the total amount of blast air required in the fluidized bed roasting method for high-sulfur, arsenic, and carbon refractory gold concentrate provided in this application accounts for 40-60% of the total blast air required in conventional oxidative roasting operations. The smaller blast air volume results in a smaller volume of flue gas emitted after roasting, which is beneficial for flue gas recovery and environmental treatment. In practical applications, the blast air volume can be reasonably adjusted according to the changes in sulfur, arsenic, and carbon content in the high-sulfur, arsenic, and carbon refractory gold concentrate to maintain the reaction temperature in the four furnace chambers between 650-680°C.

[0080] The reaction mechanism of the fluidized bed roasting system for high-sulfur, arsenic, and carbon refractory gold concentrate provided in this application is explained below.

[0081] (1) The reactions occurring in the first furnace 12 and their corresponding thermal enthalpy are as follows:

[0082] FeS2+2.75O2=0.5Fe2O3+2SO2 (1)△H1=-824.3kJ

[0083] FeAsS+2.5O2=0.5Fe2O3+0.5As2O3+SO2 (2)△H2=-1781.7kJ

[0084] C+O2=CO2 (3)△H3=-394.5kJ

[0085] FeS2=FeS+S (4)△H4=132.74kJ

[0086] FeAsS=FeS+As (5)△H5=32.35kJ

[0087] 2S+2As=As2S2 (6)△H6=-228.32kJ

[0088] 3S+2As=As2S3 (7)△H7=-336.36kJ

[0089] In the first furnace 12, only air is supplied to the wind chamber and the amount of blast air is controlled. At this time, due to insufficient oxygen, only a portion of sulfide minerals (including arsenopyrite) and carbonaceous matter undergo complete oxidation reactions in the first furnace 12, namely the reactions of reactions (1), (2), and (3). However, because the heat released by these three complete oxidation reactions is very large, it is sufficient to maintain the furnace temperature at 650-680℃. Under these temperature and limited oxygen conditions, a large amount of thermal decomposition reactions of pyrite (FeS2) and arsenopyrite (FeAsS) minerals, as well as the combination reaction of sulfur and arsenic, will also occur in the first furnace 12. The thermal decomposition reaction of pyrite and arsenopyrite minerals is an endothermic reaction, but the heat absorbed is much smaller than that of the combination reaction of sulfur and arsenic, which is conducive to maintaining the stability of the furnace temperature.

[0090] The products obtained from the thermal decomposition reaction of pyrite and arsenopyrite include sulfur (S) with a boiling point of 444.6℃, SO2 with a boiling point of -10℃, arsenic trioxide (As2O3, commonly known as arsenic) with a boiling point of 461℃, arsenic disulfide (As2S2, commonly known as realgar) with a boiling point of 565℃, carbon dioxide (CO2) with a boiling point of -31℃, and carbon monoxide (CO) with a boiling point of -140.23℃. The boiling points of these products are all lower than the roasting temperature in the furnace and are mixed into the flue gas in gaseous state. The remaining products, ferrous sulfide (FeS), iron oxide (Fe2O3), and arsenic trisulfide (As2S3, commonly known as orpiment, with a boiling point of 723℃), have boiling points higher than the roasting temperature in the furnace and remain in the ore sand after the first roasting.

[0091] (2) The reactions occurring in the second furnace 14 and their corresponding thermal enthalpies are as follows:

[0092] 3SO2+4FeAsS=2Fe2O3+2As2S2+3S (8)△H8=-421.43kJ;

[0093] 3SO2+4FeAsS=2Fe2O3+2As2S3+S (9)△H9=-548.17kJ;

[0094] SO2 + C = CO2 + S (10) △H 10 = -46.93kJ;

[0095] As2O3+2FeS2=Fe2O3+As2S2+2S (11)△H 11 = 96.13 kJ;

[0096] As2O3+2FeS2=Fe2O3+As2S3+S (12)△H 12 =32.76kJ;

[0097] As2O3+2FeS=Fe2O3+As2S2 (13)△H 13= -169.35kJ;

[0098] As2O3+1.5C=1.5CO2+2As (14)△H 14 =35.67kJ;

[0099] The As produced in reaction (14) reacts with S in reactions (6) and (7), that is,

[0100] 2S+2As=As2S2 (6)△H6=-228.32kJ

[0101] 3S+2As=As2S3 (7)△H7=-336.36kJ

[0102] The flue gas produced in the first furnace 12 contains S, SO2, As2O3, As2S2, CO2, CO, and dust. It is introduced into the second furnace 14 and reacts with FeS, FeS2, FeAsS, and C in the ore flowing into the second furnace 14 in reactions (6) to (14). It can be seen that the reaction between SO2 and FeAsS is an exothermic reaction with a large amount of heat, the reaction between SO2 and C is an exothermic reaction with a small amount of heat, the reactions between As2O3 and FeS2 and between As2O3 and C are endothermic reactions with a small amount of heat, while the reaction between As2O3 and FeS is an exothermic reaction with a large amount of heat. This is because the molar amount of FeS in the ore flowing into the second furnace 14 is much greater than the molar amount of FeS2, FeAsS, and C. Therefore, the overall reaction in the second furnace 14 is an exothermic reaction. Furthermore, because the four-chamber fluidized bed roasting device A provided in this application is connected in series with four chambers, the heat loss of the roasted ore sand during the process of entering the rear furnace from the front furnace is very small. Therefore, the temperature in the second furnace 14 can still be maintained at 650-680℃.

[0103] The reaction in the second furnace 14 significantly reduces the SO2 content in the flue gas. Most of the As2O3 is converted into As2S2 in a gaseous state or As2S3 in a solid state through the reaction. The flue gas discharged from the second furnace 14 contains a large amount of S, As2S2, CO, CO2, and soot, as well as a small amount of SO2 and a very small amount of As2O3. After secondary roasting, FeS2, FeAsS and C in the ore sand are further oxidized or decomposed, with very little or almost no residual content. The residual sulfur and arsenic mainly exist in the form of FeS and As2S3.

[0104] (3) The main reactions occurring in the third furnace 16 are those represented by equations (13), (10), (14), (6), and (7), namely:

[0105] As2O3+2FeS=Fe2O3+As2S2 (13)△H 13= -169.35kJ;

[0106] SO2 + C = CO2 + S (10) △H 10 = -46.93kJ;

[0107] As2O3+1.5C=1.5CO2+2As (14)△H 14 =35.67kJ;

[0108] 2S+2As=As2S2 (6)△H6=-228.32kJ

[0109] 3S+2As=As2S3 (7)△H7=-336.36kJ

[0110] The third furnace 16 receives flue gas generated from the reaction in the fourth furnace 18, which mainly contains a large amount of S, SO2, CO2, and As2O3. The ore flowing into the third furnace 16 contains very little FeS2, FeAsS, and C, with a relatively high FeS content. Therefore, As2O3 reacts with FeS in reaction formula (13), significantly reducing the As2O3 content in the flue gas. Simultaneously, to ensure that SO2 and As2O3 in the flue gas fully react and convert into S, As2S2, and As2S3, an appropriate amount of carbon source is added to the third furnace 16. C reacts with SO2 and As2O3 in reactions formulas (10) and (14), and the generated S further reacts with As in reactions formulas (6) and (7), generating As2S2 and As2S3.

[0111] As can be seen, among the reactions in the third furnace 16, only the reaction between As2O3 and C is an endothermic reaction, and the amount of heat absorbed is relatively small. The overall thermal effect is still an exothermic reaction, which helps to maintain the temperature in the third furnace 16 at 650-680℃.

[0112] The reaction in the third furnace 16 significantly increases the content of S steam and As2S2 steam in the furnace. The flue gas discharged from the third furnace 16 contains a large amount of S, As2S2, CO, CO2, soot, as well as a small amount of SO2 and a very small amount of As2O3. In the ore sand after three roastings, FeS2 and FeAsS are almost completely decomposed, the FeS content is further reduced, and the As2S3 content is increased. In addition, some unreacted carbon remains (including the original carbon in the gold concentrate and the carbon source added in the third furnace 16).

[0113] (4) The main reactions occurring in the fourth furnace 18 and their corresponding thermal enthalpies are as follows:

[0114] 2FeS+3.5O2=Fe2O3+2SO2 (15)△H 15 = -1219.0 kJ;

[0115] 2FeS+1.5O2=Fe2O3+2S (16)△H 16 = -523.79kJ;

[0116] As2S3+4.5O2=As2O3+3SO2 (17)△H 17 = -819.74kJ;

[0117] O2 + C = CO2 (18) △H 18 = -394.5kJ;

[0118] SO2 + C = CO2 + S (10) △H 10 = -46.93kJ;

[0119] Only air is supplied to the wind chamber of the fourth furnace 18, ensuring the complete oxidation of residual sulfides and carbon in the ore flowing into it. The sulfides include FeS, As₂S₃, and possibly residual FeAsS. The carbon includes the original carbon from the gold concentrate and the carbon source supplemented from the third furnace 16. It can be seen that all reactions occurring in the fourth furnace 18 are exothermic, with a relatively large overall heat release. The furnace temperature can still be maintained between 650-680℃ by adjusting the amount of blast air.

[0120] The flue gas produced by the reaction in the fourth furnace chamber 18 mainly contains S, SO2, CO2 and As2O3, while the ore sand after the fourth roasting is the final roasted sand, which is mainly gold-containing iron oxide (Fe2O3).

[0121] In the high-temperature carbon bed reactor 7 and the medium-temperature carbon bed reactor 5 of the flue gas recovery device B, the reaction of formula (10) mainly occurs. In addition, the trace amount of As2O3 remaining in the flue gas is also removed in the high-temperature carbon bed reactor 7 by the reaction of formula (14), that is:

[0122] SO2 + C = CO2 + S (10) △H 10 = -46.93kJ;

[0123] As2O3+1.5C=1.5CO2+2As (14)△H 14 =35.67kJ;

[0124] Since the As2O3 content is very low, the overall reaction is still exothermic. Furthermore, since the devices along the flue gas transmission path are all wrapped with insulation materials, heat loss is minimal, which helps maintain the temperature in the reactor.

[0125] The specific embodiments of the fluidized bed roasting method for high-sulfur, arsenic, and carbon refractory gold concentrate provided in this application are as follows.

[0126] Example 2

[0127] Example 2 provides a method for pretreating high-sulfur, arsenic, and carbon refractory gold concentrate based on the fluidized bed roasting system provided in Example 1. The method includes the following steps: Pretreatment of high-sulfur, arsenic, and carbon refractory gold concentrate containing 39.31% sulfur, 1.95% arsenic, 1.85% carbon, 34.29% iron, and a gold grade of 15.70 g / t.

[0128] In step S1, high-sulfur, arsenic, and carbon refractory gold concentrate is fed into the first furnace 12, and air is introduced into the first air chamber 23 to raise the temperature and initiate a reaction. Subsequently, the roasted ore flows into the second furnace 14, while only the flue gas produced in the first furnace 12 is introduced into the second air chamber 26 to continue the reaction. Next, the ore, after a second roasting, flows into the third furnace 16, while only the flue gas produced in the fourth furnace 18 is introduced into the third air chamber 29 to continue the reaction, with carbon source being added to the third furnace 16 during the process. Finally, the ore, after a third roasting, flows into the fourth furnace 18, and air is introduced into the fourth air chamber 31 to continue the reaction. After the reaction is complete, the roasted ore is discharged.

[0129] The amount of air introduced into the first furnace 12 is 646 m³ / ton of gold concentrate. 3 The air volume introduced into the fourth furnace 18 is 517 m³ / ton of gold concentrate. 3 The amount of pulverized coal added to the third furnace 16 is 30 kg per ton of gold concentrate.

[0130] During the reaction, the reaction temperature in all four furnace chambers was maintained between 650-680℃ by adjusting the amount of air introduced.

[0131] The flue gas generated from the reactions in S2, the second furnace 14, and the third furnace 16 undergoes two dust removal processes before entering the flue gas recovery device B. First, it is passed into the high-temperature carbon bed reactor 7, where most of the SO2 and all of the As2O3 are removed through reaction at a temperature of 580-600℃. Then, it is passed into the realgar recovery unit 6, where realgar is recovered from the flue gas through condensation at a temperature of 480℃-520℃. Next, it is passed into the medium-temperature carbon bed reactor 5, where residual SO2 is further removed through reaction at a temperature above 450℃. Then, it is passed into the sulfur recovery unit 4, where sulfur is recovered through condensation at a temperature of 200℃-240℃. Finally, it is passed into the heat exchanger 3, where the flue gas is cooled to 30-40℃ to remove water vapor, and the resulting condensate is recycled. Finally, the remaining flue gas is passed into the flue gas purifier 2 for neutralization with lime slurry or alkaline solution, and then discharged into the atmosphere through the fifth induced draft blower 36 and the flue gas emission device 1.

[0132] The final discharged calcined sand was weighed and its components were tested. The recovered sulfur and realgar were weighed and their purity was tested. The recovery rates of sulfur and arsenic were calculated, and the data are as follows:

[0133] (1) The yield of roasted sand obtained by pretreatment based on the fluidized bed roasting system for high sulfur, arsenic and carbon refractory gold concentrate in Example 1 was 72.01%, of which the roasted sand contained 0.29% sulfur, 0.05% arsenic and 20.80 g / t gold.

[0134] (2) Each ton of high-sulfur, arsenic, and carbon refractory gold concentrate yields 379.58 kg of sulfur, with a sulfur recovery rate of 96.58% and a sulfur purity greater than 99%; each ton of high-sulfur, arsenic, and carbon refractory gold concentrate yields 27.15 kg of realgar, with an arsenic recovery rate of 97.45% and a realgar purity greater than 90%. It can be seen that the purity of both sulfur and realgar meets the sales standards.

[0135] If the traditional roasting method is used, and the air volume is calculated based on an air coefficient of 1.20, the air volume required per ton of gold concentrate is 2583 m³. 3 In this embodiment, the amount of blast air in the first furnace 12 accounts for 25% of the blast air in the traditional roasting method, the amount of blast air in the fourth furnace 18 accounts for 20% of the blast air in the traditional roasting method, and the total amount of blast air accounts for 45% of the blast air in the traditional roasting method.

[0136] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.

Claims

1. A fluidized bed roasting system for high-sulfur, arsenic, and carbon refractory gold concentrate, characterized in that, The fluidized bed roasting system for high-sulfur, arsenic, and carbon refractory gold concentrate includes a four-furnace fluidized bed roasting device and a flue gas recovery device; wherein, the four-furnace fluidized bed roasting device includes a first furnace, a second furnace, a third furnace, and a fourth furnace connected in sequence and decreasing in horizontal height, and the bottom of the four furnaces is respectively provided with a first air chamber, a second air chamber, a third air chamber, and a fourth air chamber that communicate with the furnace. The first air chamber is provided with a first air inlet pipe on its side wall, and the first air inlet pipe is connected to a first blower; specifically, the air inlet end of the first air inlet pipe is connected to the air outlet of the first blower to introduce air into the first air chamber. The second air inlet pipe is provided on the side wall of the second air chamber. The second air inlet pipe is sequentially connected to the third induced draft blower, the first cyclone dust collector, and the top of the first furnace. Specifically, the air inlet end of the second air inlet pipe is connected to the air outlet of the third induced draft blower, the air inlet of the third induced draft blower is connected to the exhaust port of the first cyclone dust collector, and the air inlet of the first cyclone dust collector is connected to the top of the first furnace, so as to introduce the flue gas generated in the reaction in the first furnace into the second air chamber. A third air inlet pipe is provided on the side wall of the third air chamber. The third air inlet pipe is sequentially connected to the fourth induced draft blower, the fourth cyclone dust collector, and the top of the fourth furnace. Specifically, the air inlet end of the third air inlet pipe is connected to the air outlet of the fourth induced draft blower, the air inlet of the fourth induced draft blower is connected to the exhaust outlet of the fourth cyclone dust collector, and the air inlet of the fourth cyclone dust collector is connected to the top of the fourth furnace, so as to introduce the flue gas generated in the reaction in the fourth furnace into the third air chamber. The fourth air chamber is provided with a fourth air inlet pipe on its side wall, and the fourth air inlet pipe is connected to the second blower; specifically, the air inlet end of the fourth air inlet pipe is connected to the air outlet of the second blower to introduce air into the fourth air chamber. The flue gas recovery device includes a high-temperature carbon bed reactor, a realgar recovery unit, a medium-temperature carbon bed reactor, and a sulfur recovery unit connected in sequence to react SO2 and As2O3 in the flue gas and recover realgar and sulfur in steps.

2. The fluidized bed roasting system for high-sulfur, arsenic, and carbon refractory gold concentrate according to claim 1, characterized in that, The top of the second furnace is connected to the flue gas recovery device via a second cyclone dust collector, a first induced draft blower, and a first bag filter connected in sequence. Specifically, the top of the second furnace is connected to the air inlet of the second cyclone dust collector, the exhaust port of the second cyclone dust collector is connected to the air inlet of the first induced draft blower, the air outlet of the first induced draft blower is connected to the air inlet of the first bag filter, and the exhaust port at the top of the first bag filter is connected to the high-temperature carbon bed reactor of the flue gas recovery device B. The top of the third furnace is connected to the high-temperature carbon bed reactor of the flue gas recovery device via a third cyclone dust collector, a second induced draft blower, and a second bag filter connected in sequence. Specifically, the top of the third furnace is connected to the air inlet of the third cyclone dust collector, the exhaust port of the third cyclone dust collector is connected to the air inlet of the second induced draft blower, the exhaust port of the second induced draft blower is connected to the air inlet of the second bag filter, and the exhaust port at the top of the second bag filter is connected to the high-temperature carbon bed reactor of the flue gas recovery device B. The bottoms of the first bag filter and the second bag filter are respectively connected to the flue gas feed pipe located on the side wall of the fourth furnace.

3. The fluidized bed roasting system for high-sulfur, arsenic, and carbon refractory gold concentrate according to claim 1, characterized in that, The flue gas recovery device also includes a heat exchanger, a flue gas purifier, a fifth induced draft blower, and a flue gas exhaust device, which are connected in sequence with the sulfur recovery unit.

4. The fluidized bed roasting system for high-sulfur, arsenic, and carbon refractory gold concentrate according to claim 2, characterized in that, The first furnace chamber and the second furnace chamber, the second furnace chamber and the third furnace chamber, and the third furnace chamber and the fourth furnace chamber are all separated by heat-resistant steel plates.

5. The fluidized bed roasting system for high-sulfur, arsenic, and carbon refractory gold concentrate according to claim 4, characterized in that, The first furnace chamber is provided with a feed inlet on its side wall, the third furnace chamber is provided with a pulverized coal replenishment pipe on its side wall, and the fourth furnace chamber is provided with a roasted sand outlet on its side wall.

6. The fluidized bed roasting system for high-sulfur, arsenic, and carbon refractory gold concentrate according to claim 5, characterized in that, The cone and dust pipe of the first cyclone dust collector extend into the second furnace chamber, the cone and dust pipe of the second cyclone dust collector extend into the third furnace chamber, the cone and dust pipe of the third cyclone dust collector extend into the fourth furnace chamber, and the dust pipe of the fourth cyclone dust collector is located near the calcined sand outlet.

7. The fluidized bed roasting system for high-sulfur, arsenic, and carbon refractory gold concentrate according to claim 1, characterized in that, All the upper parts of the cyclone dust collectors, all the induced draft blowers, all the bag filters, all the carbon bed reactors, and the flue gas ducts connecting the components in the fluidized bed roasting system for high-sulfur arsenic carbon refractory gold concentrate are wrapped with thermal insulation material.

8. A method for boiling roasting high-sulfur, arsenic, and carbon refractory gold concentrate based on the boiling roasting system for high-sulfur, arsenic, and carbon refractory gold concentrate according to any one of claims 1-7, characterized in that, Includes the following steps: S1, high-sulfur, arsenic, and carbon refractory gold concentrate is fed into the first furnace, and air is introduced into the first air chamber to raise the temperature and react. Subsequently, the roasted ore flows into the second furnace, while only the flue gas generated in the first furnace is introduced into the second air chamber to continue the reaction. Next, the ore that has undergone secondary roasting flows into the third furnace, while only the flue gas generated in the fourth furnace is introduced into the third air chamber to continue the reaction. During the reaction, a carbon source is added to the third furnace. Finally, the ore that has undergone tertiary roasting flows into the fourth furnace, and air is introduced into the fourth air chamber to continue the reaction. After the reaction is completed, the roasted ore is discharged. S2, the flue gas generated in the second and third furnaces is treated by two dust removal processes before entering the flue gas recovery device. First, it is passed into the high-temperature carbon bed reactor to remove most of the SO2 and all of the As2O3 through reaction. Then, it is passed into the realgar recovery unit to recover the realgar in the flue gas. Next, it is passed into the medium-temperature carbon bed reactor to further remove the residual SO2 through reaction. Then, it is passed into the sulfur recovery unit to recover sulfur. Then, it is passed into the heat exchanger for cooling and dehydration. Finally, the remaining flue gas is passed into the flue gas purifier for neutralization with lime milk or alkaline solution. Finally, it is discharged into the atmosphere through the fifth induced draft blower and the flue gas emission device.

9. The fluidized bed roasting method for high-sulfur, arsenic, and carbon refractory gold concentrate according to claim 8, characterized in that, In step S1, the reaction temperature in all four furnaces is maintained between 650-680℃; in step S2, the reaction temperature in the high-temperature carbon bed reactor is higher than 570℃, the realgar recovery unit uses a condensation method to recover realgar at a temperature of 480℃-520℃, the reaction temperature in the medium-temperature carbon bed reactor is higher than 450℃, the sulfur recovery unit uses a condensation method to recover sulfur at a temperature of 200℃-280℃, and the cooling and dehydration in the heat exchanger specifically refers to cooling the flue gas to 30-50℃ to remove water vapor, and recycling the resulting condensate; the carbon bed material replaced in the high-temperature carbon bed reactor and the medium-temperature carbon bed reactor is mixed into the carbon source to be fed into the third furnace, and fed into the third furnace together in step S1.

10. The fluidized bed roasting method for high-sulfur, arsenic, and carbon refractory gold concentrate according to claim 9, characterized in that, The high-sulfur, arsenic, and carbon refractory gold concentrate refers to refractory gold concentrate with a sulfur content greater than or equal to 30% and an arsenic and carbon content greater than 1% respectively; the total amount of blast air required in the fluidized bed roasting method of the high-sulfur, arsenic, and carbon refractory gold concentrate accounts for 40-60% of the total amount of blast air in the traditional oxidative roasting operation.

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