Method for controllable preparation of micro / nano-sized antimony sulfide by volatilizing antimony-containing sand in microwave field

Abstract

The application discloses a method for controllably preparing micro / nano-scale antimony sulfide by volatilizing antimony flower sand under a microwave field and belongs to the technical field of resource recovery. The application provides a preparation method for micro / nano-scale antimony sulfide, which is short in flow, green and environment-friendly, mild in conditions and capable of quickly realizing accurate control of particle size and morphology, so that micro / nano-scale antimony sulfide material with regular morphology, uniform particle size, large specific surface area and excellent photoelectric performance can be obtained, so as to meet the urgent needs of high performance, low cost and green preparation in the fields of energy storage, photoelectric detection, photoelectric devices and the like. Through directional adhesion and self-assembly process, the application realizes efficient and controllable construction of hierarchical micro / nano structure with spherical regularity, uniform and adjustable particle size and stable structure, and the super-large specific surface area of the material can endow the material with rich surface states, effectively enhance light capture efficiency, promote photo-generated carrier separation and transmission, and further comprehensively improve the photoelectric response and stability of the device.

Description

Technical Field

[0001] This invention relates to the field of resource recycling technology, and in particular to a method for the controllable preparation of micro / nano-scale antimony sulfide by volatilizing antimony flocs under a microwave field. Background Technology

[0002] With the rapid development of new energy, the Internet of Things, flexible electronics, and advanced optoelectronic technologies, the demand for high-performance, low-cost, and environmentally friendly semiconductor materials has become increasingly urgent. Among them, antimony sulfide (Sb₂S₃) exhibits enormous application potential in numerous fields due to its comprehensive advantages, including a suitable bandgap (approximately 1.7 eV), high light absorption coefficient, high theoretical specific capacity, good environmental compatibility, and abundant raw material reserves. In energy storage, Sb₂S₃ possesses high theoretical specific capacity and excellent cycle stability, making it an ideal candidate material for anodes in alkali metal-ion batteries. In sensing, its low detection limit, wide response range, and high selectivity make it suitable for constructing highly sensitive chemical and biological sensors. In optoelectronics, Sb₂S₃'s bandgap of approximately 1.7 eV matches the solar spectrum well, and its theoretical photoelectric conversion efficiency can reach 28%, making it highly competitive in devices such as photocatalysis, photodetectors, and solar cells.

[0003] However, current high-performance antimony sulfide materials heavily rely on chemical synthesis, resulting in extremely high costs and severe environmental pollution during production, becoming a core bottleneck for their large-scale application. If natural stibnite could be directly converted into high-performance antimony sulfide materials through a short process, production costs would be significantly reduced and environmental pollution minimized. However, natural stibnite particles are large and the system energy is low, leading to poor electrochemical performance for direct use in energy storage and other fields. The main reason for this is that the large particle size of the natural sulfide system significantly prolongs ion migration paths, reduces surface active sites, and exacerbates charge recombination and volume expansion, resulting in decreased electrochemical and photoelectric performance, deteriorated cycle stability, and poor film formation. In contrast, small-sized Sb₂S₃ with its unique morphology, large specific surface area, significant size effect, short carrier transport path, and excellent processability, can effectively enhance light capture, promote carrier separation and transport, and improve device sensitivity and stability, making it a highly anticipated core functional material in the field of high-end optoelectronic devices.

[0004] However, existing technologies for the preparation, modification, and related processes of small-sized high-purity antimony sulfide still have many shortcomings: conventional wet and pyrometallurgical processes are generally cumbersome, consume large amounts of reagents, cause severe equipment corrosion, and have high costs and energy consumption. They are also prone to particle agglomeration and difficulty in controlling the size and morphology, making it difficult to obtain high-quality small-sized Sb2S3 materials. Some interface modification and orientation control methods are complex and require harsh conditions, which can easily change the intrinsic band gap of the material, making it difficult to achieve both efficient carrier transport and ideal band gap matching. Traditional device structures lack defect passivation and self-healing capabilities, and are prone to microcracks under mechanical stress, leading to performance degradation.

[0005] Furthermore, existing technology (CN 118062891 A) reports a method for preparing nano-sized antimony sulfide from natural stibnite, but it still suffers from drawbacks such as long process time, the need for strong acids and organic reagents such as concentrated sulfuric acid and polyvinylpyrrolidone, and the potential generation of toxic and harmful substances, which do not conform to the modern concept of green preparation. Patent (CN 113620343 B) also discloses a method for preparing micro- and nano-sized antimony sulfide, but it suffers from defects such as difficulty in separating particle sizes and poor uniformity, failing to meet the requirements for size differentiation in nanodevice assembly and composite material modification, and severely restricting the large-scale application of antimony sulfide in multiple fields. Therefore, how to use natural stibnite as raw material to achieve low-cost, low-pollution, and highly efficient preparation of micron- and nano-sized functional antimony sulfide with controllable size and morphology has become a key technical challenge that urgently needs to be overcome in the field of antimony sulfide materials. Summary of the Invention

[0006] The purpose of this invention is to provide a method for controllably preparing micro / nano-scale antimony sulfide by volatilizing antimony flocs under a microwave field, thereby solving the aforementioned problems in the background art. To overcome the shortcomings of traditional antimony sulfide preparation methods, such as high cost, significant pollution, low utilization of natural minerals, and difficulty in precisely controlling product morphology and particle size, this invention provides a method for preparing micro / nano-scale antimony sulfide that is short-process, environmentally friendly, and operates under mild conditions, enabling rapid and precise control of particle size and morphology. This method can yield micro / nano-scale antimony sulfide materials with regular morphology, uniform particle size, large specific surface area, and excellent photoelectric properties, meeting the urgent needs for high-performance, low-cost, and green preparation in fields such as energy storage, photoelectric detection, and optoelectronic devices.

[0007] To achieve the above objectives, the present invention provides the following technical solution: One of the technical solutions of this invention is to provide a method for controllably preparing micro / nano-scale antimony sulfide by volatilizing antimony flocs under a microwave field, comprising the following steps: (1) Prepare antimony sulfide ore powder, granulate it to obtain shaped pellets; (2) The shaped pellets are placed in the heating chamber of a microwave heating device and heated to remove impurities under a protective atmosphere and microwave conditions; (3) After the heating and impurity removal process is completed, the temperature is raised to 700~850℃ for roasting. During the roasting process, based on the graded temperature control condensation strategy, the gaseous products volatilized during the roasting process flow out of the heating chamber and flow through the upstream condensation zone and the downstream condensation zone in sequence. The temperature of the upstream condensation zone is maintained at 200~300℃, and the temperature of the downstream condensation zone is maintained at 80~200℃. After the calcination process is completed, nano-sized antimony sulfide powder is collected in the downstream condensation zone, and micro-sized antimony sulfide powder is collected in the upstream condensation zone.

[0008] Preferably, the antimony sulfide ore powder has a sieve particle size of 100-200 mesh.

[0009] Preferably, the particle size of the shaped pellets is 1~4 mm.

[0010] Preferably, the protective atmosphere is nitrogen with a purity of not less than 99%, and the rate at which the protective atmosphere is introduced is 0.1~1.0 m. 3 / h.

[0011] Introducing nitrogen gas during the roasting process (nitrogen's weak absorption capacity does not affect the volatilization of antimony sulfide) can prevent oxygen from entering the reaction chamber during roasting, thus preventing antimony sulfide from reacting with oxygen. At the same time, the blowing out of nitrogen gas can drive the antimony sulfide vapor to different condensation zones.

[0012] Preferably, the temperature for the heating and impurity removal treatment is 400℃, the holding time is 30~40 min, and the heating rate is 10~50℃ / min, more preferably 15~35℃ / min.

[0013] Preferably, the calcination temperature is 750~850℃.

[0014] The inventors discovered that the calcination temperature has a significant impact on the volatilization rate of antimony sulfide. If the calcination temperature is too low, the temperature required for antimony sulfide volatilization will not be reached; if the calcination temperature is too high, the reactants will sinter, blocking the pores that allow antimony sulfide to volatilize, making it difficult for antimony sulfide to diffuse outward in gaseous form.

[0015] Preferably, the roasting time is 60-120 min, more preferably 80-100 min.

[0016] Preferably, the elemental composition of the antimony sulfide ore powder is as follows: Sb 20~50 wt%, Si 25~55 wt%, Fe 5~10 wt%, Al 2~5 wt%, and other elements 1~3 wt% (the upper limit of the above element content will not be reached simultaneously in the same sample, and the total mass fraction of all elements in each sample is 100 wt.%).

[0017] Preferably, the quartz tube has the following dimensions: outer diameter 6 cm, wall thickness 0.3 cm, inner diameter 5.4 cm, and length 62 cm.

[0018] Preferably, the microwave roasting power is 800~2500 W, more preferably 1200~2000 W, and the frequency is 2450 MHz or 915 MHz.

[0019] Preferably, the downstream condensation zone is 1-8 cm from the pipe opening, and the upstream condensation zone is 8-18 cm from the pipe opening.

[0020] During the roasting process, antimony sulfide in the raw material rapidly volatilizes and flows sequentially with nitrogen through an upstream condensation zone at 200–300°C and a downstream condensation zone at 80–200°C. In the upstream condensation zone at 200–300°C, the molecular motion speed and crystal growth rate are relatively fast, and the antimony sulfide in this temperature region grows into micron-sized antimony sulfide. The energy provided by the temperature in the downstream condensation zone is insufficient to allow the antimony sulfide crystal nuclei to form a long-range ordered lattice structure, so amorphous nano-sized antimony sulfide is collected in this region.

[0021] Preferably, the method includes the following steps: (1) Raw material pretreatment: After crushing and grinding the antimony-containing sand (antimony sulfide ore) raw material, it is sieved to obtain powder with a sieve particle size of 100~200 mesh; then it is granulated by adding deionized water as a binder and rolling it in the granulator to obtain granules with a particle size of 1 mm~4 mm and a moisture content of 5~15%. The granules are then dried and pretreated, with the drying temperature controlled at 50~120℃ and the drying time at 10~120 min. (2) Loading and calcination: The pellets obtained in step (1) are evenly spread in a quartz boat with a loading thickness of 5-20 mm; after loading the quartz boat into the quartz tube, it is placed in the high-temperature heating zone in the middle of the quartz tube opening at 25-40 cm to ensure that the pellets are in a uniform heating area of ​​the microwave field; microwave calcination is carried out in a protective gas atmosphere, first heating to 400℃ at a heating rate of 10-50℃ / min, and holding at that temperature for 30-40 minutes. The process involves removing organic flotation material and low-boiling-point substances from the raw material and activating antimony sulfide using the unique heating and electromagnetic field effects of microwaves (i.e., directly and selectively acting on Sb-S bonds through microwave energy, inducing molecular polarization and microscopic thermal effects, creating conditions for subsequent volatilization). The temperature is then further increased to the target temperature of 700-850℃ for calcination to prioritize the volatilization and separation of antimony sulfide, while retaining impurities with boiling points higher than antimony sulfide in the system to prevent volatilization, thus obtaining high-purity antimony sulfide. The calcination process at 700-850℃ lasts for 60-120 minutes, with temperature fluctuations monitored in real time and temperature stability maintained by adjusting the microwave power. (3) Condensation and collection: Based on the graded temperature control condensation strategy, during the high-temperature roasting process, the volatilized gaseous products flow through different temperature zone condensation units in sequence: the medium temperature zone of 200~300℃ can be condensed and crystallized to form black micron-sized antimony sulfide, and the low temperature zone of 80~200℃ can efficiently prepare orange-red nano-sized antimony sulfide by strengthening the condensation nucleation effect; the gradient condensation system includes multiple independently temperature-controlled condensation zones; in terms of temperature control, the temperature of the middle high temperature zone is monitored in real time by infrared, and the microwave equipment automatically adjusts the microwave output power to stabilize the target temperature; the temperature range of each temperature zone is controlled by the furnace insulation structure, microwave power and carrier gas flow rate, and finally a multi-level temperature distribution that can realize band condensation is formed.

[0022] Treating the pellets in step (1) can form a moderately loose porous structure, which is conducive to the diffusion of antimony sulfide vapor generated during the roasting process from the inside of the pellets to the surface, thereby improving the selective volatilization efficiency of antimony and the product yield.

[0023] After testing, the inventors discovered that processing antimony sulfide ore into the aforementioned small spherical shape during roasting makes the material more compact and the voids more evenly and rationally distributed. During roasting, the nitrogen hot gas flow can penetrate the gaps between particles, avoiding overheating or under-roasting problems caused by local powder agglomeration, making the material reaction rate more consistent and the product purity higher.

[0024] The prepared nano-sized and micron-sized antimony sulfide can reach a purity of 99.9% and have a uniform particle size distribution, making them suitable for optoelectronic, catalytic, or energy storage applications.

[0025] More preferably, the temperature of the drying pretreatment is 80~100℃.

[0026] More preferably, the thickness of the filling material is 10-16 mm.

[0027] The beneficial technical effects of the present invention are as follows: To overcome the drawbacks of traditional antimony sulfide preparation methods, such as high cost, significant pollution, low utilization of natural minerals, and difficulty in precisely controlling product morphology and particle size, this invention provides a method for preparing micro / nano-scale antimony sulfide that is short-process, environmentally friendly, and under mild conditions, enabling rapid and precise control of particle size and morphology. This method can produce micro / nano-scale antimony sulfide materials with regular morphology, uniform particle size, large specific surface area, and excellent photoelectric properties, thus meeting the urgent need for high-performance, low-cost, and green preparation in fields such as energy storage, photoelectric detection, and optoelectronic devices.

[0028] The spherical micro and nano antimony sulfide prepared by this invention achieves efficient and controllable construction of hierarchical micro and nano structures with regular spherical shape, uniform and adjustable particle size, and stable structure through directional attachment and self-assembly processes. Its ultra-large specific surface area can endow the material with rich surface states, effectively enhancing light capture efficiency, promoting the separation and transport of photogenerated carriers, and thus comprehensively improving the photoelectric response and stability of the device.

[0029] This invention directly uses antimony sulfide ore (antimony grade 20-50%) as raw material to prepare high-purity antimony sulfide with a purity of not less than 99.9%, greatly reducing the dependence on antimony sulfide concentrate. This not only alleviates the pressure of antimony resource depletion but also realizes the high-value resource utilization of solid waste, achieving both economic and environmental benefits. Furthermore, this invention can achieve efficient separation of antimony slag, with a direct antimony recovery rate of up to 99.41%, and the antimony content in the final residue can be as low as 0.16%.

[0030] Compared to conventional volatilization roasting temperatures, microwave heating offers advantages such as rapid heating and hot spot effects. It enables the local temperature inside the mineral to quickly reach the temperature required for antimony sulfide volatilization, allowing antimony sulfide to volatilize preferentially. The required temperature is only 700~850℃, avoiding the problem of co-volatilization with other compounds, and has significant advantages in low-temperature smelting.

[0031] This invention can simultaneously prepare antimony sulfide particles of micron and nanometer size, meeting the differentiated requirements of antimony sulfide particle size for different application scenarios (such as nanodevice assembly, composite material modification, etc.), and providing a high-quality foundation for material applications in energy storage, sensors, semiconductors and other fields. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This is a process flow diagram for the controllable preparation of micro / nano-sized antimony sulfide by volatilizing antimony flocs under a microwave field, according to the present invention.

[0034] Figure 2 The images show the XRD patterns of antimony sulfide powder prepared in Example 1 of this invention. (a) is the XRD pattern of nano-sized antimony sulfide powder, and (b) is the XRD pattern of micron-sized antimony sulfide powder.

[0035] Figure 3The images show the SEM and EDS spectra of the nano-sized antimony sulfide powder prepared in Example 1 of this invention. (a), (b), and (c) are SEM images at different locations, and (d) is the EDS spectrum.

[0036] Figure 4 The images show the SEM and EDS spectra of the micron-sized antimony sulfide powder prepared in Example 1 of this invention. (a), (b), and (c) are SEM images at different locations, and (d) is the EDS spectrum.

[0037] Figure 5 Optical characterization images of the micron-sized and nano-sized antimony sulfide powders prepared in Example 1 of this invention are shown. In the image, (a) is the ultraviolet-visible spectrum, and (b) is the (ahv) spectrum derived from (a). 2 Relationship diagram with (hv). Detailed Implementation

[0038] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention. It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the present invention.

[0039] Furthermore, regarding the numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, are also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0040] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. It should be noted that any aspects of this invention not described in detail are conventional practices in the art and are not the focus of this invention.

[0041] The terms “comprising,” “including,” “having,” “containing,” etc., used in this invention are all open-ended terms, meaning that they include but are not limited to.

[0042] The chemical composition of the antimony sulfide slag raw material used in the following embodiments of the present invention is shown in Table 1.

[0043] Table 1. Chemical composition (wt.%) of antimony sulfide slag The present invention will be further described below with reference to specific implementation schemes. The specific calculation method for the direct recovery rate of Sb in this implementation scheme is as follows: In the formula, γ1 represents the volatilization rate, γ2 represents the direct recovery rate of Sb, M1 and M2 represent the mass of the residue before and after volatilization, respectively, and C1 and C2 represent the content of Sb element in the residue before and after volatilization, respectively.

[0044] The dimensions of the quartz tube used in this invention are: outer diameter 6 cm, wall thickness 0.3 cm, inner diameter 5.4 cm, and length 62 cm.

[0045] In the microwave tube furnace of the present invention, the position 25-40 cm from the opening of the quartz tube is the middle heating cavity, the position 8-18 cm from the opening of the quartz tube is the upstream condensation zone, and the position 1-8 cm from the opening of the quartz tube is the downstream condensation zone.

[0046] All raw materials used in the following embodiments and comparative examples of the present invention are commercially available products.

[0047] Example 1 A method for controllably preparing micro / nano-sized antimony sulfide by volatilizing antimony flocs under a microwave field, comprising the following steps: (1) Accurately weigh 10 g of 150 mesh antimony sulfide ore powder (slag) and put it into a granulator. Add deionized water as a binder and roll it in the granulator to obtain granules with a particle size of 1 mm to 4 mm and a moisture content of 10%. Then, perform a drying pretreatment on the granules, controlling the drying temperature at 80℃ and the drying time at 80 min.

[0048] (2) The dried spherical raw material is evenly spread in the quartz boat, with the material thickness controlled at 10-16 mm; then the quartz boat containing the material is placed in the middle heating cavity of the microwave tube furnace, 25-40 cm away from the quartz tube opening. The rate of introducing the protective atmosphere is 0.4 m. 3 At 10:00 a.m., the circulating cooling system and microwave power supply were turned on, and the temperature was increased to 400°C at 30°C / min. The temperature was then held for 30 min to remove low-boiling-point impurities from the raw materials. The experiment used a microwave heating device (HY-ZG3012) with a working frequency of 2450 MHz. The microwave output power was set in the range of 0.8~2.5 kW. The system automatically controlled the temperature by adjusting the microwave power to ensure that the real-time temperature was maintained at the target temperature.

[0049] (3) Continue to raise the temperature to 800℃ and keep it warm for 80 min. During this period, based on the graded temperature control condensation strategy, the gaseous products volatilized during the high-temperature roasting process flowed through different temperature condensation units with nitrogen. The downstream condensation zone 1~8 cm from the pipe opening was kept at 80~200℃ by the system monitoring and adjustment, and the upstream condensation zone 8~18 cm from the pipe opening was kept at 200~300℃ by the microwave system monitoring and adjustment.

[0050] (4) After the reaction is complete, turn off the microwave and stop the protective gas supply after the furnace body cools down naturally. Collect orange-red nano-sized antimony sulfide powder in the downstream condensation zone and black micron-sized antimony sulfide powder in the upstream condensation zone.

[0051] (5) The orange-red nano-sized antimony sulfide powder and the black micron-sized antimony sulfide powder prepared in step (4) were tested separately, and then the following data were calculated: the volatility of the raw material was 33.52%, the direct antimony recovery rate was 99.41%, and the antimony content in the residue was 0.16%. The purity of the prepared antimony sulfide reached 99.9%.

[0052] Example 2 (1) Accurately weigh 10 g of 150 mesh antimony sulfide ore powder (slag) and put it into a granulator. Add deionized water as a binder and roll it in the granulator to obtain granules with a particle size of 1 mm to 4 mm and a moisture content of 10%. Then, perform a drying pretreatment on the granules, controlling the drying temperature at 80℃ and the drying time at 80 min.

[0053] (2) The dried spherical raw material is evenly spread in the quartz boat, with the material thickness controlled at 10-16 mm; then the quartz boat containing the material is placed in the middle heating cavity of the microwave tube furnace, 25-40 cm away from the quartz tube opening. The rate of introducing the protective atmosphere is 0.4 m. 3 At 10:00 a.m., the circulating cooling system and microwave power supply were turned on, and the temperature was increased to 400°C at 30°C / min. The temperature was then held for 30 min to remove low-boiling-point impurities from the raw materials. The experiment used a microwave heating device (HY-ZG3012) with a working frequency of 2450 MHz. The microwave output power was set in the range of 0.8~2.5 kW. The system automatically controlled the temperature by adjusting the microwave power to ensure that the real-time temperature was maintained at the target temperature.

[0054] (3) Continue to raise the temperature to 700℃ and keep it warm for 80 min. During this period, based on the graded temperature control condensation strategy, the gaseous products volatilized during the high-temperature roasting process flow through different temperature range condensation units in sequence. The downstream condensation zone 1~8 cm from the pipe opening is always kept at 80~200℃ by the system monitoring and adjustment, and the upstream condensation zone 8~18 cm from the pipe opening is always kept at 200~300℃ by the microwave system monitoring and adjustment.

[0055] (4) After the reaction is complete, turn off the microwave and stop the protective gas supply after the furnace body cools down naturally. Collect nano-sized antimony sulfide powder in the downstream condensation zone and collect micron-sized antimony sulfide in the upstream condensation zone.

[0056] (5) The prepared orange-red nano-sized antimony sulfide powder and black micron-sized antimony sulfide powder were tested separately, and then the following data were calculated: the volatility of the raw material was 28.01%, the direct recovery rate of antimony was 95.34%, and the antimony content in the residue was 1.56%.

[0057] Example 3 (1) Accurately weigh 10 g of 150 mesh antimony sulfide ore powder (slag) and put it into a granulator. Add deionized water as a binder and roll it in the granulator to obtain granules with a particle size of 1 mm to 4 mm and a moisture content of 10%. Then, perform a drying pretreatment on the granules, controlling the drying temperature at 80℃ and the drying time at 80 min.

[0058] (2) The dried spherical raw material is evenly spread in the quartz boat, with the material thickness controlled at 10-16 mm; then the quartz boat containing the material is placed in the middle heating cavity of the microwave tube furnace, 25-40 cm away from the quartz tube opening. The rate of introducing the protective atmosphere is 0.4 m. 3 At 10:00 a.m., the circulating cooling system and microwave power supply were turned on, and the temperature was increased to 400°C at 30°C / min. The temperature was then held for 30 min to remove low-boiling-point impurities from the raw materials. The experiment used a microwave heating device (HY-ZG3012) with a working frequency of 2450 MHz. The microwave output power was set in the range of 0.8~2.5 kW. The system automatically controlled the temperature by adjusting the microwave power to ensure that the real-time temperature was maintained at the target temperature.

[0059] (3) Continue to raise the temperature to 750℃ and keep it warm for 80 min. During this period, based on the graded temperature control condensation strategy, the gaseous products volatilized during the high-temperature roasting process flowed through different temperature condensation units with nitrogen. The downstream condensation zone 1~8 cm from the pipe opening was kept at 80~200℃ by the system monitoring and adjustment, and the upstream condensation zone 8~18 cm from the pipe opening was kept at 200~300℃ by the microwave system monitoring and adjustment.

[0060] (4) After the reaction is complete, turn off the microwave and stop the protective gas supply after the furnace body cools down naturally. Collect nano-sized antimony sulfide powder in the downstream condensation zone and collect micron-sized antimony sulfide in the upstream condensation zone.

[0061] (5) The prepared orange-red nano-sized antimony sulfide powder and black micron-sized antimony sulfide powder were tested separately, and then the following data were calculated: the volatility of the raw material was 32.01%, the direct recovery rate of antimony was 98.04%, and the antimony content in the residue was 0.71%.

[0062] Example 4 (1) Accurately weigh 10 g of 150 mesh antimony sulfide ore powder (slag) and put it into a granulator. Add deionized water as a binder and roll it in the granulator to obtain granules with a particle size of 1 mm to 4 mm and a moisture content of 10%. Then, perform a drying pretreatment on the granules, controlling the drying temperature at 80℃ and the drying time at 80 min.

[0063] (2) The dried spherical raw material is evenly spread in the quartz boat, with the material thickness controlled at 10-16 mm; then the quartz boat containing the material is placed in the middle heating cavity of the microwave tube furnace, 25-40 cm away from the quartz tube opening. The rate of introducing the protective atmosphere is 0.4 m. 3 At 10:00 a.m., the circulating cooling system and microwave power supply were turned on, and the temperature was increased to 400°C at 30°C / min. The temperature was then held for 30 min to remove low-boiling-point impurities from the raw materials. The experiment used a microwave heating device (HY-ZG3012) with a working frequency of 2450 MHz. The microwave output power was set in the range of 0.8~2.5 kW. The system automatically controlled the temperature by adjusting the microwave power to ensure that the real-time temperature was maintained at the target temperature.

[0064] (3) Continue to raise the temperature to 800℃ and keep it warm for 60 min. During this period, based on the graded temperature control condensation strategy, the gaseous products volatilized during the high-temperature roasting process flowed through different temperature condensation units with nitrogen. The downstream condensation zone 1~8 cm from the pipe opening was kept at 80~200℃ by the system monitoring and adjustment, and the upstream condensation zone 8~18 cm from the pipe opening was kept at 200~300℃ by the microwave system monitoring and adjustment.

[0065] (4) After the reaction is complete, turn off the microwave and stop the protective gas supply after the furnace body cools down naturally. Collect nano-sized antimony sulfide powder in the downstream condensation zone and collect micron-sized antimony sulfide in the upstream condensation zone.

[0066] (6) The prepared orange-red nano-sized antimony sulfide powder and black micron-sized antimony sulfide powder were tested separately, and then the following data were calculated: the volatility of the raw material was 29.51%, the direct recovery rate of antimony was 95.12%, and the antimony content in the residue was 1.63%.

[0067] Example 5 (1) Accurately weigh 10 g of 150 mesh antimony sulfide ore powder (slag) and put it into a granulator. Add deionized water as a binder and roll it in the granulator to obtain granules with a particle size of 1 mm to 4 mm and a moisture content of 10%. Then, perform a drying pretreatment on the granules, controlling the drying temperature at 80℃ and the drying time at 80 min.

[0068] (2) The dried spherical raw material is evenly spread in the quartz boat, with the material thickness controlled at 10-16 mm; then the quartz boat containing the material is placed in the middle heating cavity of the microwave tube furnace, 25-40 cm away from the quartz tube opening. The rate of introducing the protective atmosphere is 0.4 m. 3 At 10:00 a.m., the circulating cooling system and microwave power supply were turned on, and the temperature was increased to 400°C at 30°C / min. The temperature was then held for 30 min to remove low-boiling-point impurities from the raw materials. The experiment used a microwave heating device (HY-ZG3012) with a working frequency of 2450 MHz. The microwave output power was set in the range of 0.8~2.5 kW. The system automatically controlled the temperature by adjusting the microwave power to ensure that the real-time temperature was maintained at the target temperature.

[0069] (3) Continue to raise the temperature to 800℃ and keep it warm for 100 min. During this period, based on the graded temperature control condensation strategy, the gaseous products volatilized during the high-temperature roasting process flowed through different temperature condensation units with nitrogen. The downstream condensation zone 1~8 cm from the pipe opening was kept at 80~200℃ by the system monitoring and adjustment, and the upstream condensation zone 8~18 cm from the pipe opening was kept at 200~300℃ by the microwave system monitoring and adjustment.

[0070] (4) After the reaction is complete, turn off the microwave and stop the protective gas supply after the furnace body cools down naturally. Collect nano-sized antimony sulfide powder in the downstream condensation zone and collect micron-sized antimony sulfide in the upstream condensation zone.

[0071] (5) The prepared orange-red nano-sized antimony sulfide powder and black micron-sized antimony sulfide powder were tested separately, and then the following data were calculated: the volatility of the raw material was 33.43%, the direct recovery rate of antimony was 99.16%, and the antimony content in the residue was 0.32%.

[0072] Example 6 (1) Accurately weigh 10 g of 150 mesh antimony sulfide ore powder (slag) and put it into a granulator. Add deionized water as a binder and roll it in the granulator to obtain granules with a particle size of 1 mm to 4 mm and a moisture content of 10%. Then, perform a drying pretreatment on the granules, controlling the drying temperature at 80℃ and the drying time at 80 min.

[0073] (2) The dried spherical raw material is evenly spread in the quartz boat, with the material thickness controlled at 10-16 mm; then the quartz boat containing the material is placed in the middle heating cavity of the microwave tube furnace, 25-40 cm away from the quartz tube opening. The rate of introducing the protective atmosphere is 0.4 m. 3 At 10:00 a.m., the circulating cooling system and microwave power supply were turned on, and the temperature was increased to 400°C at 30°C / min. The temperature was then held for 30 min to remove low-boiling-point impurities from the raw materials. The experiment used a microwave heating device (HY-ZG3012) with a working frequency of 2450 MHz. The microwave output power was set in the range of 0.8~2.5 kW. The system automatically controlled the temperature by adjusting the microwave power to ensure that the real-time temperature was maintained at the target temperature.

[0074] (3) Continue to raise the temperature to 800℃ and keep it warm for 80 min. During this period, based on the graded temperature control condensation strategy, the gaseous products volatilized during the high-temperature roasting process flowed through different temperature condensation units with nitrogen. The downstream condensation zone 1~8 cm from the pipe opening was kept at 80~200℃ by the system monitoring and adjustment, and the upstream condensation zone 8~18 cm from the pipe opening was kept at 200~300℃ by the microwave system monitoring and adjustment.

[0075] (4) After the reaction is complete, turn off the microwave and stop the supply of protective gas (nitrogen) after the furnace body cools down naturally. Collect nano-sized antimony sulfide powder in the downstream condensation zone and collect micron-sized antimony sulfide in the upstream condensation zone.

[0076] (5) The prepared orange-red nano-sized antimony sulfide powder and black micron-sized antimony sulfide powder were tested separately, and then the following data were calculated: the volatility of the raw material was 26.25%, the direct recovery rate of antimony was 95.21%, and the antimony content in the residue was 0.14%.

[0077] Example 7 (1) Accurately weigh 10 g of 150 mesh antimony sulfide ore powder (slag) and put it into a granulator. Add deionized water as a binder and roll it in the granulator to obtain granules with a particle size of 1 mm to 4 mm and a moisture content of 10%. Then, pre-dry the granules and control the drying temperature to 80℃ and the drying time to 80 min.

[0078] (2) The dried spherical raw material is evenly spread in the quartz boat, with the material thickness controlled at 10-16 mm; then the quartz boat containing the material is placed in the middle heating cavity of the microwave tube furnace, 25-40 cm away from the quartz tube opening. The rate of introducing the protective atmosphere is 0.4 m. 3 At 10:00 a.m., the circulating cooling system and microwave power supply were turned on, and the temperature was increased to 400°C at 30°C / min. The temperature was then held for 30 min to remove low-boiling-point impurities from the raw materials. The experiment used a microwave heating device (HY-ZG3012) with a working frequency of 2450 MHz. The microwave output power was set in the range of 0.8~2.5 kW. The system automatically controlled the temperature by adjusting the microwave power to ensure that the real-time temperature was maintained at the target temperature.

[0079] (3) Continue to raise the temperature to 800℃ and keep it warm for 80 min. During this period, based on the graded temperature control condensation strategy, the gaseous products volatilized during the high-temperature roasting process flowed through different temperature condensation units with nitrogen. The downstream condensation zone 1~8 cm from the pipe opening was kept at 80~200℃ by the system monitoring and adjustment, and the upstream condensation zone 8~18 cm from the pipe opening was kept at 200~300℃ by the microwave system monitoring and adjustment.

[0080] (4) After the reaction is complete, turn off the microwave and stop the protective gas supply after the furnace body cools down naturally. Collect nano-sized antimony sulfide powder in the downstream condensation zone and collect micron-sized antimony sulfide in the upstream condensation zone.

[0081] (5) The prepared orange-red nano-sized antimony sulfide powder and black micron-sized antimony sulfide powder were tested separately, and then the following data were calculated: the volatility of the raw material was 33.43%, the direct recovery rate of antimony was 99.14%, and the antimony content in the residue was 0.31%.

[0082] Example 8 (1) Accurately weigh 10 g of 150 mesh antimony sulfide ore powder (slag) and put it into a granulator. Add deionized water as a binder and roll it in the granulator to obtain granules with a particle size of 1 mm to 4 mm and a moisture content of 5 to 15%. Then, perform a drying pretreatment on the granules, controlling the drying temperature at 50 to 120°C and the drying time at 10 to 120 min.

[0083] (2) The dried spherical raw material is evenly spread in the quartz boat, with the material thickness controlled at 10-16 mm; then the quartz boat containing the material is placed in the middle heating cavity of the microwave tube furnace, 25-40 cm away from the quartz tube opening. The rate of introducing the protective atmosphere is 0.4 m. 3At 10:00 a.m., the circulating cooling system and microwave power supply were turned on, and the temperature was increased to 400°C at 30°C / min. The temperature was then held for 30 min to remove low-boiling-point impurities from the raw materials. The experiment used a microwave heating device (HY-ZG3012) with a working frequency of 2450 MHz. The microwave output power was set in the range of 0.8~2.5 kW. The system automatically controlled the temperature by adjusting the microwave power to ensure that the real-time temperature was maintained at the target temperature.

[0084] (3) Continue to raise the temperature to 850℃ and keep it warm for 80 min. During this period, based on the graded temperature control condensation strategy, the gaseous products volatilized during the high-temperature roasting process flow through different temperature condensation units with nitrogen. The downstream condensation zone 1~8 cm from the pipe opening is always kept at 80~200℃ by the system monitoring and adjustment, and the upstream condensation zone 8~18 cm from the pipe opening is always kept at 200~300℃ by the microwave system monitoring and adjustment.

[0085] (4) After the reaction is complete, turn off the microwave and stop the protective gas supply after the furnace body cools down naturally. Collect nano-sized antimony sulfide powder in the downstream condensation zone and collect micron-sized antimony sulfide in the upstream condensation zone.

[0086] (5) The prepared orange-red nano-sized antimony sulfide powder and black micron-sized antimony sulfide powder were tested separately, and then the following data were calculated: the raw material volatility rate was 33.03%, the antimony direct recovery rate was 99.29%, and the antimony content in the residue was 0.24%.

[0087] Comparative Example 1 The only difference from Example 1 is that the microwave heating roasting temperature in step (3) is changed from 800°C to 600°C, while the other operations and parameters are the same as in Example 1.

[0088] The volatile antimony sulfide index of Comparative Example 1 was as follows: the volatility of the raw material was 4.13%, the direct antimony recovery rate was 64.23%, and the antimony content in the residue was 9.08%.

[0089] Comparative Example 2 The only difference from Example 1 is that the microwave heating roasting temperature in step (3) is changed from 800°C to 650°C, while the other operations and parameters are the same as in Example 1.

[0090] Comparative Example 2 yielded the following volatile antimony sulfide indexes: the volatility of the raw material was 10.04%, the direct antimony recovery rate was 68.75%, and the antimony content in the residue was 8.47%.

[0091] Comparative Example 3 The only difference from Example 1 is that the microwave heating holding time in step (3) is changed from 80 min to 20 min, while the other operations and parameters are the same as in Example 1.

[0092] Comparative Example 3 yielded the following volatile antimony sulfide indexes: raw material volatility rate of 16.42%, direct antimony recovery rate of 73.80%, and antimony content in residue of 7.56%.

[0093] Comparative Example 4 The only difference from Example 1 is that the microwave heating holding time in step (3) is changed from 80 min to 40 min, while the other operations and parameters are the same as in Example 1.

[0094] Comparative Example 4 yielded the following volatile antimony sulfide indexes: raw material volatility rate of 28.12%, direct antimony recovery rate of 80.61%, and antimony content in residue of 6.46%.

[0095] Comparative Example 5 The only difference from Example 1 is that the sieve particle size of the antimony sulfide powder in step (3) is changed from 150 mesh to 50 mesh, while other operations and parameters are the same as in Example 1.

[0096] Comparative Example 5 yielded the following volatile antimony sulfide indexes: raw material volatility rate of 20.12%, direct antimony recovery rate of 93.67%, and antimony content in residue of 1.91%.

[0097] Comparative Example 6 The only difference from Example 1 is that the microwave treatment in the heating process of steps (2) and (3) is omitted, and a conventional tube furnace is used to replace the microwave heating method. Other operations and parameters are the same as in Example 1.

[0098] Comparative Example 6 yielded the following volatile antimony sulfide indexes: raw material volatility rate of 14.86%, antimony direct recovery rate of 56.89%, and antimony content in residue of 12.36%.

[0099] Comparing Examples 1, 2, 3, and 8 with Comparative Examples 1 and 2, it can be seen that limiting the temperature of the entire volatilization system to 700~800℃ can result in a volatilization rate of raw materials of over 28%, a direct antimony recovery rate of over 95%, and an antimony content of less than 1.6% in the residue.

[0100] Comparing Examples 1, 4, and 5 with Comparative Examples 3 and 4, it can be seen that the holding time of the entire reduction system is limited to 60-100 min, the volatility of the raw materials is above 29%, the direct antimony recovery rate is above 95%, and the antimony content in the residue is below 1.7%.

[0101] Comparing Examples 1, 6, 7 and Comparative Example 5, it can be seen that controlling the particle size of antimony sulfide ore powder to 100-200 mesh is beneficial to the volatilization of antimony sulfide.

[0102] Comparing Example 1 with Comparative Examples 1, 2, and 6, it can be seen that compared with conventional heating, microwave roasting greatly reduces the reaction temperature and increases the volatilization rate of antimony sulfide, thereby reducing energy consumption and input costs.

[0103] Figure 1 This is a process flow diagram for the controllable preparation of micro / nano-sized antimony sulfide by volatilizing antimony flocs under a microwave field, according to the present invention.

[0104] Figure 2 The images show the XRD patterns of antimony sulfide powder prepared in Example 1 of this invention. (a) is the XRD pattern of nano-sized antimony sulfide powder, and (b) is the XRD pattern of micron-sized antimony sulfide powder.

[0105] Figure 3 The images show the SEM and EDS spectra of the nano-sized antimony sulfide powder prepared in Example 1 of this invention. (a), (b), and (c) are SEM images at different locations, and (d) is the EDS spectrum.

[0106] Figure 4 The images show the SEM and EDS spectra of the micron-sized antimony sulfide powder prepared in Example 1 of this invention. (a), (b), and (c) are SEM images at different locations, and (d) is the EDS spectrum.

[0107] from Figure 3-4 It can be seen that the micron-sized and nano-sized antimony sulfide powders prepared in Example 1 both exhibit smooth spherical morphologies and relatively uniform size.

[0108] Figure 5 Optical characterization images of the micron-sized and nano-sized antimony sulfide powders prepared in Example 1 of this invention are shown. In the image, (a) is the ultraviolet-visible spectrum, and (b) is the (ahv) spectrum derived from (a). 2 Relationship diagram with (hv).

[0109] Table 2 shows the content data of various impurity elements obtained by ICP elemental analysis of the antimony trisulfide powder prepared in Example 1 of the present invention.

[0110] Table 2 The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for controllably preparing micro / nano-sized antimony sulfide by volatilizing antimony flocs under a microwave field, characterized in that, Includes the following steps: (1) Prepare antimony sulfide ore powder, granulate it to obtain shaped pellets; (2) The shaped pellets are placed in the heating chamber of a microwave heating device and heated to remove impurities under a protective atmosphere and microwave conditions; (3) After the heating and impurity removal process is completed, the temperature is further increased to 700~850℃ for roasting. During the roasting process, based on the staged temperature control condensation strategy, the gaseous products volatilized during the roasting process flow out of the heating chamber and flow through the upstream condensation zone and the downstream condensation zone in sequence. The temperature of the upstream condensation zone is maintained at 200~300℃, and the temperature of the downstream condensation zone is maintained at 80~200℃. After the calcination process is completed, nano-sized antimony sulfide powder is collected in the downstream condensation zone, and micro-sized antimony sulfide powder is collected in the upstream condensation zone.

2. The method according to claim 1, characterized in that, The particle size of the antimony sulfide ore powder is 100-200 mesh.

3. The method according to claim 1, characterized in that, The particle size of the shaped pellets is 1~4 mm.

4. The method according to claim 1, characterized in that, The temperature for the heating and impurity removal process is 400℃, the holding time is 30~40 min, and the heating rate is 10~50℃ / min.

5. The method according to claim 1, characterized in that, The protective atmosphere is nitrogen with a purity of not less than 99%, and the rate at which the protective atmosphere is introduced is 0.1~1.0 m. 3 / h.

6. The method according to claim 1, characterized in that, The roasting temperature is 700~850℃.

7. The method according to claim 1, characterized in that, The roasting process takes 60 to 120 minutes.

8. The method according to claim 1, characterized in that, The microwave roasting power is 800~2500 W, and the frequency is 2450 MHz or 915 MHz.

9. The method according to claim 1, characterized in that, The antimony content in the antimony sulfide ore powder is 20-50 wt%.

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