Continuous production process of high-dispersity insoluble sulfur

Abstract

The invention discloses a continuous production process of high-dispersity insoluble sulfur, and particularly relates to the technical field of chemical engineering. The process comprises the following steps: calcining pyrite under an oxygen-enriched condition to generate sulfur dioxide, and converting the sulfur dioxide into a sodium sulfite solution; adding excessive elemental sulfur into the solution to generate a polysulfide precipitate; collecting hydrogen sulfide gas and active sulfur while performing acidolysis precipitation; hydrogen sulfide and sulfur dioxide are mixed in proportion, and high-purity sulfur is regenerated through catalysis of gamma-aluminum oxide; mixing the regenerated sulfur with active sulfur, and carrying out high-temperature gasification polymerization at 700-750 DEG C under the protection of nitrogen; then the sulfur steam is in countercurrent contact with low-temperature water mist through a granulation tower and is rapidly cooled and solidified into fine particles; and finally performing vacuum drying to obtain a finished product. Through material circulation and process integration, sulfur source activation, long-chain polymer structure directional regulation and control and accurate control of particle morphology are realized. The obtained insoluble sulfur product has high insoluble content, fine and uniform particle size and excellent thermal stability.

Description

Technical Field

[0001] This invention relates to the field of chemical technology, and specifically to a continuous production process for highly dispersible insoluble sulfur. Background Technology

[0002] Insoluble sulfur, a key vulcanizing agent in the rubber industry, especially in radial tire manufacturing, is valuable because it remains stable within the rubber matrix at mixing temperatures, preventing scorching, and rapidly transforms into soluble sulfur at vulcanization temperatures to participate in cross-linking reactions, thus ensuring processing safety and product performance. Traditional production processes, such as quenching and gasification, can produce insoluble sulfur, but they generally suffer from problems such as coarse product morphology, uneven particle size distribution, and poor microdispersion. During rubber mixing, this type of sulfur is difficult to disperse uniformly, easily forming local agglomerates, leading to an uneven vulcanization network. This directly affects tire durability, dynamic mechanical properties, and appearance quality, becoming one of the long-standing pain points restricting the performance improvement of high-end rubber products.

[0003] Furthermore, existing technologies for producing insoluble sulfur generally face the challenge of insufficient thermal stability, meaning that the insoluble content decays rapidly at certain temperatures. This thermal instability leads to a decrease in the effective components of the product during storage, transportation, and high-temperature processing. This not only increases the difficulty and uncertainty of production formulation control but also affects the reproducibility and batch stability of the final product. Dispersibility and thermal stability issues are intertwined: uneven dispersion may exacerbate local thermal history differences, accelerating the decomposition of unstable components; while poor thermal stability may cause loss of effective components before use, further worsening its dispersion effect in rubber compounds, creating a vicious cycle that significantly reduces rubber processing efficiency and product qualification rate.

[0004] To overcome these shortcomings, the industry has attempted various improvement methods, such as surface modification, adding stabilizers, or optimizing post-polymerization processing to enhance performance. However, these methods often focus on post-processing modifications or improvements to single properties, making it difficult to simultaneously ensure high insoluble sulfur content while maintaining excellent dispersibility and superior thermal stability. Furthermore, they often come at the cost of sacrificing process continuity, increasing costs, or introducing impurities. Therefore, developing a new process for preparing insoluble sulfur that can achieve high dispersibility, high thermal stability, and is suitable for continuous and clean production is of urgent industrial necessity and significant technological value for meeting the increasingly stringent quality requirements of high-end rubber products, especially high-performance tires. Summary of the Invention

[0005] In order to overcome the above-mentioned defects of the prior art, the embodiments of the present invention provide a continuous production process for highly dispersible insoluble sulfur, which solves the problems of uneven product performance, low processing efficiency and poor storage stability caused by poor dispersibility and insufficient thermal stability of insoluble sulfur in the rubber industry.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A continuous production process for highly dispersible insoluble sulfur specifically includes the following steps: S1: Pyrite is calcined in an industrial oxygen atmosphere, and then the collected sulfur dioxide gas is passed into saturated hydrogen peroxide to obtain a sodium sulfite solution. S2: Add excess pulverized elemental sulfur to a sodium sulfite solution and stir to obtain Na2S. x precipitation; S3: Add hydrochloric acid dropwise to the mixed system prepared in S2 and stir to mix. At the same time, collect the generated hydrogen sulfide gas and the precipitated sulfur. Then, wash the precipitated sulfur with pure water for 30 seconds. S4: The hydrogen sulfide gas collected in S3 is mixed with the remaining sulfur dioxide gas in S1 and passed into a fixed-bed reactor with γ-alumina catalyst to catalyze the generation of sulfur and water vapor. The resulting gas is then rapidly cooled to obtain high-purity elemental sulfur. S5: The sulfur recovered in S4 is mixed with the precipitated sulfur after washing in S3, and placed in a gasification furnace. The mixture is heated under a nitrogen protective atmosphere to gasify the sulfur and polymerize the sulfur atoms into long-chain polymers. S6: The sulfur gas in S5 is sprayed out through the nozzle at the top of the granulation tower, so that the gas comes into contact with the water mist in a countercurrent flow and cools and solidifies into small granular sulfur. S7: Place the small granular sulfur obtained in S6 into a vacuum drying oven and dry it.

[0007] Preferably, the pyrite in S1 has an Fe2S content greater than 98%, and is calcined in industrial oxygen with an oxygen content of 75%.

[0008] Preferably, the Na2S in S2 x The precipitate is a mixed precipitate with a large amount of elemental sulfur adhering to the substrate, with Na2S as the base.

[0009] Preferably, the hydrochloric acid added to S3 is a hydrochloric acid solution with a mass fraction of 20~35wt%.

[0010] Preferably, H2S:SO2 in S4 is mixed in a molar ratio of 2:1 to 1.8:1.

[0011] Preferably, the γ-alumina catalyst in S4 has a particle size of 3-5 mm and a specific surface area greater than 250 m². 2 / g, then the mixed gas is heated to 280~320℃, and finally high-purity elemental sulfur is obtained by condensation and recovery at 100~120℃.

[0012] Preferably, in S5, the sulfur recovered from S4 is mixed with the sulfur precipitated by water washing in S3 at a mass ratio of 1:1 to 2.

[0013] Preferably, in step S5, the mixture is heated to a high temperature of 700~750°C and held at that temperature for 60 seconds to vaporize the sulfur.

[0014] Preferably, in step S6, the obtained sulfur gas is cooled countercurrently with water mist at a flow rate of 30-40 L / min, a temperature of 25-30°C, and a droplet size of 50-150 μm.

[0015] Preferably, in step S7, the obtained small-particle sulfur is dried in a vacuum drying oven at 80-90°C for 6-12 hours.

[0016] The technical effects and advantages of the continuous production process for highly dispersible insoluble sulfur of this invention are as follows: 1. This invention, by constructing an integrated continuous process system of pyrite oxidation to produce acid, polysulfide acidolysis, Claus catalytic regeneration, high-temperature nitrogen-protected polymerization, and low-temperature water mist countercurrent granulation, achieves synergistic effects on the chemical activation of sulfur source, directional regulation of polymer structure, and precise control of particle morphology from a mechanistic perspective. This solves the core problems of poor dispersibility and insufficient thermal stability in traditional processes in an integrated manner. Its advantages are that the produced insoluble sulfur has high insoluble content, fine and uniform particle size distribution, and excellent thermal stability, resulting in a significant improvement in overall performance.

[0017] 2. This invention, through the precise combination of high-temperature nitrogen-protected polymerization and low-temperature water mist countercurrent rapid cooling, ensures, mechanistically, that sulfur atoms fully vaporize and polymerize in an inert atmosphere to form a stable long-chain structure. Subsequently, the instantaneous supersaturation and high nucleation rate caused by the low-temperature water mist achieve uniform and rapid condensation of sulfur vapor. The advantages of this process are that it not only promotes the formation of long-chain structures but also directly endows the product with excellent micro-dispersion. The resulting fine and uniform particles effectively prevent agglomeration during rubber compounding, thereby ensuring a uniform vulcanization network and improving the mechanical properties and appearance quality of the final product.

[0018] 3. This invention improves the reactivity and purity of elemental sulfur used for polymerization by combining a raw material pretreatment path that activates the sulfur source through polysulfide acid hydrolysis with Claus catalytic regeneration of high-purity sulfur. Combined with the aforementioned high-temperature polymerization step, it constructs a sulfur long-chain polymer structure with high thermal stability. Its advantages are that it significantly enhances the product's heat resistance, effectively reduces the thermal decay rate during storage and processing, ensures the long-term stability of the product's effective components, and thus improves the controllability of rubber formulations and batch consistency of product performance.

[0019] 4. This invention, through the material recycling and continuous design of the entire process, realizes the effective utilization of resources and the close connection of processes from the mechanism. Its advantages are that it not only reduces waste emissions and meets the requirements of green production, but also greatly improves production efficiency and process controllability. At the same time, the continuous process has a certain tolerance for key parameters, which enhances the robustness and economy of production and is suitable for large-scale industrial application. Attached Figure Description

[0020] Figure 1 This is a flowchart of a continuous production process for highly dispersible insoluble sulfur proposed in this invention. Detailed Implementation

[0021] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0022] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0023] Example 1 This embodiment provides a continuous production process for highly dispersible insoluble sulfur, the specific implementation steps of which include: Experimental materials: Pyrite, industrial oxygen, saturated hydrogen peroxide, 20-35 wt% hydrochloric acid, elemental sulfur, γ-alumina catalyst, nitrogen.

[0024] Experimental objective: A continuous production process for highly dispersible insoluble sulfur is provided.

[0025] Experimental steps: S1: Pyrite is calcined in oxygen with a purity of 75%, and then the collected sulfur dioxide gas is passed into saturated hydrogen peroxide to obtain sodium sulfite solution. S2: Add excess pulverized elemental sulfur to a sodium sulfite solution and stir to obtain Na2S. x precipitation; S3: Add hydrochloric acid dropwise to the mixed system prepared in S2 and stir to mix. At the same time, collect the generated hydrogen sulfide gas and the precipitated sulfur. Then, wash the precipitated sulfur with pure water for 30 seconds. S4: The hydrogen sulfide gas collected in S3 is mixed with the remaining sulfur dioxide gas in S1 at a molar ratio of H2S:SO2 = 2:1, and then passed into a mixture packed with particles of 3mm diameter and a specific surface area >250m². 2 The γ-alumina catalyst was placed in a fixed-bed reactor and catalytically generated into sulfur and water vapor at 320 °C. The resulting gas was then rapidly cooled to 100 °C and condensed to recover high-purity elemental sulfur. S5: The sulfur recovered in S4 and the precipitated sulfur after washing in S3 are mixed at a mass ratio of 1:1, placed in a gasification furnace, heated to 750°C under a nitrogen protective atmosphere to gasify the sulfur, and held at that temperature for 60 seconds to allow the sulfur atoms to polymerize into a long-chain polymer. S6: The sulfur gas in S5 is ejected through a nozzle at the top of the granulation tower, resulting in a gas flow rate of 40 L / m³. 3 Water mist at 25℃ and droplet size of 150μm was rapidly cooled and solidified into small granular sulfur through countercurrent contact. S7: Place the small granular sulfur obtained in S6 into a vacuum drying oven at 80°C and dry it.

[0026] Experimental results: See Table 1 for details.

[0027] Table 1: Test Results of Example 1

[0028] Example 1 employs an integrated continuous process involving pyrite oxidation for acid production, polysulfide acidolysis, Claus catalytic sulfur regeneration, high-temperature nitrogen-protected polymerization, and low-temperature water mist countercurrent manufacturing. By mixing the high-purity sulfur recovered in step S4 with the active sulfur precipitated in step S3 at a 1:1 ratio, and then vaporizing the mixture at 750°C under nitrogen protection for 60 seconds, a stable long-chain structure of sulfur atoms is ensured through polymerization. The process utilizes 25°C and 40 L / m³. 3 The low-temperature water mist of 150μm droplets was rapidly cooled in a countercurrent manner to achieve instantaneous supersaturation and uniform nucleation of sulfur vapor, thereby obtaining a highly dispersed and thermally stable insoluble sulfur product with an insoluble sulfur content of greater than 99.0%, an average particle size of 15~25 micrometers, and a thermal storage decay rate of less than 8.0% at 105℃.

[0029] Example 2 This embodiment provides a continuous production process for highly dispersible insoluble sulfur, the specific implementation steps of which include: Experimental materials: Pyrite, industrial oxygen, saturated hydrogen peroxide, 20-35 wt% hydrochloric acid, elemental sulfur, γ-alumina catalyst, nitrogen.

[0030] Experimental objective: Countercurrent cooling is achieved using high-temperature water mist.

[0031] Experimental steps: S1: Pyrite is calcined in oxygen with a purity of 75%, and then the collected sulfur dioxide gas is passed into saturated hydrogen peroxide to obtain sodium sulfite solution. S2: Add excess pulverized elemental sulfur to a sodium sulfite solution and stir to obtain Na2S. x precipitation; S3: Add hydrochloric acid dropwise to the mixed system prepared in S2 and stir to mix. At the same time, collect the generated hydrogen sulfide gas and the precipitated sulfur. Then, wash the precipitated sulfur with pure water for 30 seconds. S4: The hydrogen sulfide gas collected in S3 is mixed with the remaining sulfur dioxide gas in S1 at a molar ratio of H2S:SO2 = 2:1, and then passed into a mixture packed with particles of 3mm diameter and a specific surface area >250m². 2 The γ-alumina catalyst was placed in a fixed-bed reactor and catalytically generated into sulfur and water vapor at 320 °C. The resulting gas was then rapidly cooled to 100 °C and condensed to recover high-purity elemental sulfur. S5: The sulfur recovered in S4 and the precipitated sulfur after washing in S3 are mixed at a mass ratio of 1:1, placed in a gasification furnace, heated to 750°C under a nitrogen protective atmosphere to gasify the sulfur, and held at that temperature for 60 seconds to allow the sulfur atoms to polymerize into a long-chain polymer. S6: The sulfur gas in S5 is ejected through a nozzle at the top of the granulation tower, resulting in a gas flow rate of 40 L / m³. 3 Water mist at 45℃ and droplet size of 150μm was rapidly cooled and solidified into small granular sulfur through countercurrent contact. S7: Place the small granular sulfur obtained in S6 into a vacuum drying oven at 80°C and dry it.

[0032] Experimental results: See Table 2 for details.

[0033] Table 2: Test Results of Example 2

[0034] Example 2 aimed to investigate the effect of water mist cooling temperature on product dispersibility. While keeping other conditions the same as in Example 1, the water mist temperature was increased to 45°C. The experiment showed that the higher cooling medium temperature reduced the temperature difference between sulfur vapor and water mist, slowing down the cooling rate and thus allowing sulfur atoms more time to migrate and aggregate. This resulted in the formation of particles with a diameter of 35-50 μm and potentially more uneven particle size. The final product had an insoluble sulfur content >98.5% and a thermal decay rate of 10.5%. This comparison confirmed the crucial role of low-temperature water mist at 25-30°C in achieving rapid cooling, obtaining fine and uniform particles, high dispersibility, and optimal thermal stability.

[0035] Example 3 This embodiment provides a continuous production process for highly dispersible insoluble sulfur, the specific implementation steps of which include: Experimental materials: Pyrite, industrial oxygen, saturated hydrogen peroxide, 20-35 wt% hydrochloric acid, elemental sulfur, γ-alumina catalyst, nitrogen.

[0036] Experimental objective: Lower the temperature of sulfur vaporization.

[0037] Experimental steps: S1: Pyrite is calcined in oxygen with a purity of 75%, and then the collected sulfur dioxide gas is passed into saturated hydrogen peroxide to obtain sodium sulfite solution. S2: Add excess pulverized elemental sulfur to a sodium sulfite solution and stir to obtain Na2S. x precipitation; S3: Add hydrochloric acid dropwise to the mixed system prepared in S2 and stir to mix. At the same time, collect the generated hydrogen sulfide gas and the precipitated sulfur. Then, wash the precipitated sulfur with pure water for 30 seconds. S4: The hydrogen sulfide gas collected in S3 is mixed with the remaining sulfur dioxide gas in S1 at a molar ratio of H2S:SO2 = 2:1, and then passed into a mixture packed with particles of 3mm diameter and a specific surface area >250m². 2 The γ-alumina catalyst was placed in a fixed-bed reactor and catalytically generated into sulfur and water vapor at 320 °C. The resulting gas was then rapidly cooled to 100 °C and condensed to recover high-purity elemental sulfur. S5: The sulfur recovered in S4 and the precipitated sulfur after washing in S3 are mixed at a mass ratio of 1:1, placed in a gasification furnace, heated to 600℃ under a nitrogen protective atmosphere to gasify the sulfur, and held at the temperature for 60s to allow sulfur atoms to polymerize into long-chain polymers. S6: The sulfur gas in S5 is ejected through a nozzle at the top of the granulation tower, resulting in a gas flow rate of 40 L / m³. 3Water mist at 25℃ and droplet size of 150μm was rapidly cooled and solidified into small granular sulfur through countercurrent contact. S7: Place the small granular sulfur obtained in S6 into a vacuum drying oven at 80°C and dry it.

[0038] Experimental results: See Table 3 for details.

[0039] Table 3: Test Results of Example 3

[0040] Example 3 verified the decisive role of vaporization polymerization temperature in the stability of sulfur chain structure, with the polymerization temperature lowered to 600°C. At this relatively low temperature, the activation energy of sulfur molecules is insufficient, leading to incomplete polymerization reactions between sulfur atoms and difficulty in forming sufficiently long and stable polymer chains. The effective content of insoluble sulfur in the product significantly decreased to 95.0%, and the structure was unstable, with a substantial increase in the thermal decay rate to 15.0%. This result contrasts sharply with Example 1, strongly demonstrating that the high temperature range of 700–750°C is a necessary condition to ensure the complete vaporization of sulfur and the formation of high-content, high-thermal-stability insoluble sulfur long-chain polymers.

[0041] Example 4 This embodiment provides a continuous production process for highly dispersible insoluble sulfur, the specific implementation steps of which include: Experimental materials: Pyrite, industrial oxygen, saturated hydrogen peroxide, 20-35 wt% hydrochloric acid, elemental sulfur, γ-alumina catalyst, nitrogen.

[0042] Experimental objective: Adjust the molar ratio of hydrogen sulfide and sulfur dioxide.

[0043] Experimental steps: S1: Pyrite is calcined in oxygen with a purity of 75%, and then the collected sulfur dioxide gas is passed into saturated hydrogen peroxide to obtain sodium sulfite solution. S2: Add excess pulverized elemental sulfur to a sodium sulfite solution and stir to obtain Na2S. x precipitation; S3: Add hydrochloric acid dropwise to the mixed system prepared in S2 and stir to mix. At the same time, collect the generated hydrogen sulfide gas and the precipitated sulfur. Then, wash the precipitated sulfur with pure water for 30 seconds. S4: The hydrogen sulfide gas collected in S3 is mixed with the remaining sulfur dioxide gas in S1 at a molar ratio of H2S:SO2 = 1.8:1, and then passed into a mixture packed with particles of 3mm diameter and a specific surface area >250m². 2The γ-alumina catalyst was placed in a fixed-bed reactor and catalytically generated into sulfur and water vapor at 320 °C. The resulting gas was then rapidly cooled to 100 °C and condensed to recover high-purity elemental sulfur. S5: The sulfur recovered in S4 and the precipitated sulfur after washing in S3 are mixed at a mass ratio of 1:1, placed in a gasification furnace, heated to 750°C under a nitrogen protective atmosphere to gasify the sulfur, and held at that temperature for 60 seconds to allow the sulfur atoms to polymerize into a long-chain polymer. S6: The sulfur gas in S5 is ejected through a nozzle at the top of the granulation tower, resulting in a gas flow rate of 40 L / m³. 3 Water mist at 25℃ and droplet size of 150μm was rapidly cooled and solidified into small granular sulfur through countercurrent contact. S7: Place the small granular sulfur obtained in S6 into a vacuum drying oven at 80°C and dry it.

[0044] Experimental results: See Table 4 for details.

[0045] Table 4: Test Results of Example 4 Insoluble sulfur content Average particle size Thermal storage attenuation rate at 105℃ Example 4 Greater than 98.8% 18~28μm 9.0% Example 4 adjusted the key material ratio of the Claus reaction in step S4, slightly modifying the molar ratio of H2S:SO2 from 2:1 to 1.8:1. Test results showed that the main performance indicators of the product, such as insoluble sulfur content >98.8% and thermal decay rate 9.0%, only slightly decreased compared to Example 1, with a similar average particle size range. This indicates that the catalytic sulfur regeneration step of this invention has a certain degree of process tolerance regarding the reactant ratio, and minor deviations will not lead to a drastic deterioration in product performance.

[0046] Example 5 This embodiment provides a continuous production process for highly dispersible insoluble sulfur, the specific implementation steps of which include: Experimental materials: Pyrite, industrial oxygen, saturated hydrogen peroxide, 20-35 wt% hydrochloric acid, elemental sulfur, ordinary alumina, and nitrogen.

[0047] Experimental objective: Adjust the type of alumina catalyst added to hydrogen sulfide and sulfur dioxide.

[0048] Experimental steps: S1: Pyrite is calcined in oxygen with a purity of 75%, and then the collected sulfur dioxide gas is passed into saturated hydrogen peroxide to obtain sodium sulfite solution. S2: Add excess pulverized elemental sulfur to a sodium sulfite solution and stir to obtain Na2S. x precipitation; S3: Add hydrochloric acid dropwise to the mixed system prepared in S2 and stir to mix. At the same time, collect the generated hydrogen sulfide gas and the precipitated sulfur. Then, wash the precipitated sulfur with pure water for 30 seconds. S4: Mix the hydrogen sulfide gas collected in S3 with the remaining sulfur dioxide gas in S1 at a molar ratio of H2S:SO2 = 2:1, and then pass the mixture into a container with a specific surface area <100m². 2 The catalyst was placed in a fixed-bed reactor with a concentration of / g of ordinary alumina catalyst and catalytically generated sulfur and water vapor at 320℃. The resulting gas was then rapidly cooled to 100℃ and condensed to recover high-purity elemental sulfur. S5: The sulfur recovered in S4 and the precipitated sulfur after washing in S3 are mixed at a mass ratio of 1:1, placed in a gasification furnace, heated to 750°C under a nitrogen protective atmosphere to gasify the sulfur, and held at that temperature for 60 seconds to allow the sulfur atoms to polymerize into a long-chain polymer. S6: The sulfur gas in S5 is ejected through a nozzle at the top of the granulation tower, resulting in a gas flow rate of 40 L / m³. 3 Water mist at 25℃ and droplet size of 150μm was rapidly cooled and solidified into small granular sulfur through countercurrent contact. S7: Place the small granular sulfur obtained in S6 into a vacuum drying oven at 80°C and dry it.

[0049] Experimental results: See Table 5 for details.

[0050] Table 5: Test Results of Example 5

[0051] Example 5 illustrates the indirect impact of catalyst characteristics on overall process efficiency, specifically the use of catalysts with a specific surface area >250m² in step S4. 2 / g γ-alumina catalyst replaced with ordinary alumina with a specific surface area <100m² 2 / g, the lower specific surface area leads to a reduction in the number of active sites of the catalyst, and the catalytic reaction efficiency and selectivity of H2S and SO2 decrease. The results show that the purity or yield of sulfur recovered in this step is affected, which in turn affects the quality of the raw material sulfur used for subsequent polymerization. The insoluble sulfur content of the final product decreases to 97.0%, and the thermal decay rate increases to 12.0%.

[0052] Comparative Example 1 A traditional continuous production process for highly dispersible insoluble sulfur is provided, the specific implementation steps of which include: Experimental materials: Industrial sulfur, nitrogen, and deionized water.

[0053] Experimental objective: The traditional quenching method for preparing insoluble sulfur was used as a benchmark for process comparison.

[0054] Experimental steps: S1: Place industrial sulfur in a sulfur melting kettle and heat it to 450°C to melt it; S2: Molten sulfur is sprayed into cooling water through a nozzle for quenching and solidification; S3: Collect the quenched sulfur particles and dehydrate them by centrifugation; S4: Place the dehydrated sulfur in an 80℃ oven and dry for 6 hours.

[0055] Experimental results: See Table 6 for details.

[0056] Table 6: Test Results of Comparative Example 1

[0057] Comparative Example 1 involves a simple physical quenching process where molten sulfur is directly quenched in water. This process relies solely on rapid cooling to induce the disordered aggregation of sulfur atoms, lacking controllable chemical activation and high-temperature polymerization steps. Consequently, it cannot form a stable long-chain polymer structure, resulting in low insoluble sulfur content and poor thermal stability in the product. Furthermore, the bulk quenching method causes uneven cooling and uncontrolled nucleation, leading to large particle size, wide distribution, and poor micro-dispersion. This process has a single sulfur source and is discontinuous, which fundamentally limits its ability to control structure, achieve particle uniformity, and maintain batch stability.

[0058] Example 1 employs an integrated continuous process of pyrite oxidation to produce acid, polysulfide acid hydrolysis, Claus catalytic sulfur regeneration, high-temperature nitrogen-protected polymerization, and low-temperature water mist countercurrent granulation. Under conditions of 25°C water mist, 750°C polymerization temperature, and γ-alumina catalyst, it achieves an optimal performance balance of high insoluble sulfur content, fine and uniform particle size, and low thermal decay rate, making it suitable for high-performance tires and other high-requirement rubber products.

[0059] In Example 2, the water mist temperature was increased to 45°C, which led to a decrease in the cooling rate, an increase in the sulfur particle size, and an increase in the thermal decay rate to 10.5%, indicating that low-temperature water mist plays a key role in particle refinement and thermal stability.

[0060] Example 3 used a lower polymerization temperature. Although the particle size was well controlled, the insoluble sulfur content decreased significantly to 95.0%, and the thermal decay rate increased to 15.0%, proving that high-temperature polymerization is crucial for the formation of a stable long-chain structure.

[0061] In Example 4, the H2S:SO2 ratio was slightly adjusted to 1.8:1, and the product performance remained at a high level, indicating that the Claus reaction section has a certain degree of process tolerance.

[0062] Example 5 uses a common alumina catalyst with a low specific surface area, which results in a decrease in the insoluble sulfur content to 97.0% and an increase in the thermal decay rate to 12.0%, highlighting the importance of high specific surface area γ-alumina for reaction efficiency and product purity.

[0063] Comparative Example 1 uses the traditional quenching method. The product has an insoluble sulfur content of only 92.5%, a wide particle size distribution, and a thermal decay rate as high as 18.5%, which clearly highlights the functional limitations of the traditional process in terms of dispersibility, thermal stability, and product uniformity.

[0064] Comparing the examples and comparative examples, Example 1 achieves the optimal balance between high-temperature polymerization and low-temperature rapid cooling. Its ingenious integrated continuous process design improves the product's dispersibility and thermal stability, making it suitable for high-performance tires and other high-end rubber products. Example 2, while increasing the water mist temperature, suffers from insufficient cooling rate, leading to increased particle size and thermal decay rate. Example 3, using a lower polymerization temperature, achieves good particle size control but fails to form a stable long-chain structure, resulting in a significant decrease in thermal stability. Example 4 fine-tunes the Claus reactant ratio, but maintains a high level of product performance with only a slight decrease. Example 5 uses a low-activity catalyst, but reaction efficiency and product purity are affected, leading to an overall performance reduction. The comparative examples highlight the limitations of traditional quenching methods in terms of dispersibility, thermal stability, and product uniformity. Therefore, this invention, through the synergistic effect of material recycling, high-temperature polymerization, and low-temperature rapid cooling, achieves continuous production of highly dispersible, highly thermally stable insoluble sulfur, demonstrating significant advantages over traditional processes.

[0065] refer to Figure 1 Starting with pyrite, the process involves calcination and polysulfide acid hydrolysis to activate the sulfur source, followed by the catalytic regeneration of high-purity sulfur using the Claus reaction. This achieves efficient sulfur recycling. The core stage involves high-temperature gasification and polymerization of the regenerated active sulfur under nitrogen protection to form a stable long-chain structure. Subsequently, low-temperature water mist countercurrent granulation technology is used to precisely control the particle morphology, and finally, vacuum drying yields the finished product. The entire process is integrated and continuous, with structural and morphological control collaboratively achieved within a closed system, resulting in the efficient production of highly dispersible, thermally stable, insoluble sulfur.

[0066] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of protection of the claims.

[0067] In conclusion, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A continuous process for the production of high dispersibility insoluble sulphur, characterized in that, Specifically comprising the following steps: S1: pyrite is calcined in an industrial oxygen atmosphere, and then the collected sulfur dioxide gas is passed into saturated hydrogen peroxide to obtain a sodium sulfite solution; S2: Add excess ground S elemental substance to the sodium sulfite solution, stir to obtain Na2S x precipitate; S3: hydrochloric acid is added dropwise to the mixed system prepared in S2, and the generated hydrogen sulfide gas and precipitated sulfur are collected while stirring, and then the precipitated sulfur is washed with pure water for 30s; S4: the hydrogen sulfide gas collected in S3 is mixed with the remaining sulfur dioxide gas in S1, and is passed into a fixed bed reactor of γ-alumina catalyst to catalytically generate sulfur and water vapor, and then the obtained gas is rapidly cooled to obtain high-purity elemental sulfur; S5: the sulfur recovered in S4 is mixed with the precipitated sulfur washed with water in S3, and is placed in a gasification furnace and heated under a nitrogen protective atmosphere to make the sulfur gasify and make the sulfur atoms polymerize into long-chain polymers; S6: the sulfur gas in S5 is sprayed out through the nozzle at the top of the granulation tower, so that the gas is in countercurrent contact with the water mist to rapidly cool and solidify into small granular sulfur; S7: the small granular sulfur obtained in S6 is placed in a vacuum drying box for drying.

2. A process for continuous production of high dispersibility insoluble sulphur as claimed in claim 1 wherein, The pyrite in S1 has a Fe2S content of more than 98%, and is calcined under an industrial oxygen with an oxygen content of 75%.

3. A process for continuous production of high dispersibility insoluble sulphur as claimed in claim 1 wherein, Na2S in S2 x The precipitate is a mixed precipitate in which a large amount of S elementary substance is attached to the substrate based on Na2S.

4. A process for continuous production of high dispersibility insoluble sulphur as claimed in claim 1 wherein, The hydrochloric acid added in S3 is a hydrochloric acid solution with a mass fraction of 20-35wt%.

5. A process for continuous production of high dispersibility insoluble sulphur as claimed in claim 1 wherein, In S4, H2S:SO2 is mixed at a molar ratio of 2:1-1.8:

1.

6. A process for continuous production of high dispersibility insoluble sulphur as claimed in claim 1 wherein, The particle size of the γ-alumina catalyst in S4 is 3-5 mm, and the specific surface area is greater than 250 m 2 / g, then the mixed gas is heated to 280-320℃, and finally high-purity elemental sulfur is recovered by condensation at 100-120℃.

7. A process for continuous production of high dispersibility insoluble sulphur as claimed in claim 1 wherein, In S5, the sulfur recovered from S4 is mixed with the water-washed precipitated sulfur in S3 at a mass ratio of 1:1-2.

8. A process for continuous production of high dispersibility insoluble sulphur as claimed in claim 1 wherein, In S5, the mixture is heated to a high temperature of 700-750℃ and kept for 60s to make the sulfur gasify.

9. A process for continuous production of high dispersibility insoluble sulphur as claimed in claim 1 wherein, In S6, the obtained sulfur gas is countercurrently cooled with water mist with a flow rate of 30-40L / min, 25-30℃, and a liquid droplet size of 50-150μm.

10. A process for continuous production of high dispersibility insoluble sulphur as claimed in claim 1 wherein, In S7, the obtained small granular sulfur is placed in a vacuum drying box at 80-90℃ for drying for 6-12h.

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