Preparation method and device for insoluble sulfur

Abstract

The present invention relates to the technical field of insoluble sulfur production, and in particular to a method and apparatus for preparing insoluble sulfur. The method for preparing insoluble sulfur comprises the following steps: (A) mixing liquid sulfur and hydrogen sulfide gas and performing a cracking reaction at 500-550°C; (B) adding a mixture of sulfur and carbon disulfide after the cracking reaction and cooling the mixture to obtain a crude insoluble sulfur product and a soluble sulfur liquid; and (C) solidifying the mixture of the soluble sulfur liquid and the crude insoluble sulfur product at 75-85°C for 1-3 hours, washing, and drying the mixture to obtain the insoluble sulfur. This preparation method effectively improves the conversion rate of insoluble sulfur and the thermal stability of the product; and unreacted sulfur and other substances in the system can be recycled.

Description

Technical Field

[0001] The invention relates to the technical field of insoluble sulfur production, and in particular to a method and device for preparing insoluble sulfur. Background Art

[0002] Insoluble sulfur (IS) is a linear polymer formed by the ring-opening polymerization of ordinary sulfur above the critical temperature (159°C), also known as μ-sulfur (Sμ). Insoluble sulfur is a non-toxic, flammable yellow powder, named because it is insoluble in carbon disulfide. Its molecular characterization is S n The number of sulfur atoms n is greater than 200, and the maximum is 1×10 8 Because its structure is similar to that of high molecular polymers, it is also called polymerized sulfur.

[0003] Insoluble sulfur, primarily used as a high-grade accelerator and vulcanizing agent in the rubber industry, is widely used in the production of tires and other rubber composite products. Examples include tire carcass compounds, cushion compounds, white sidewall compounds, and rubber-to-carcass compounds for retreads, hoses, and tapes. It is also used in rubber compounds for cables, rubber rollers, oil seals, rubber shoes, and other rubber products. Soluble sulfur is an essential raw material in tire production. With the radialization of tires, demand for insoluble sulfur has grown rapidly, leading to increasing research interest in insoluble sulfur in recent years.

[0004] Currently, traditional insoluble sulfur production methods face challenges in quality stability, safety, environmental protection, conversion rate, and high costs. The pursuit of high-quality insoluble sulfur often comes at the expense of yield. The insoluble sulfur conversion rate, calculated based on the raw sulfur, is relatively low. For safety and quality assurance, the remaining sulfur is disposed of as waste sulfur.

[0005] In view of this, the present invention is proposed. Summary of the Invention

[0006] The first object of the present invention is to provide a method for preparing insoluble sulfur, which improves the conversion rate of insoluble sulfur and the stability of the product, and realizes the recycling of unreacted substances in the system, thereby reducing costs.

[0007] The second object of the present invention is to provide a device for implementing the above-mentioned method for preparing insoluble sulfur, which can realize assembly line operation and improve production efficiency.

[0008] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are adopted:

[0009] The present invention provides a method for preparing insoluble sulfur, comprising the following steps:

[0010] (A) Liquid sulfur and hydrogen sulfide gas are mixed and cracked at 500-550°C;

[0011] (B) After the cracking reaction, a mixture of sulfur and carbon disulfide is added and cooled to obtain an insoluble sulfur crude product and a sulfur-soluble liquid;

[0012] (C) solidifying the mixture of the sulfur-dissolving liquid and the crude insoluble sulfur at 75-85° C. for 1-3 hours, washing and drying to obtain the insoluble sulfur.

[0013] Furthermore, in step (A), the mass ratio of the liquid sulfur to the hydrogen sulfide gas is 1:0.0005-0.0015.

[0014] Furthermore, in step (B), the temperature of the mixture of sulfur and carbon disulfide is 57-63°C.

[0015] Furthermore, in step (B), the mixture of sulfur and carbon disulfide is mainly obtained by mixing carbon disulfide at a temperature of 15 to 20°C and sulfur at a temperature of 450 to 600°C.

[0016] Furthermore, in step (C), the mass ratio of the sulfur-dissolving liquid to the insoluble sulfur crude product is 1.8-2.2:1.

[0017] Furthermore, in the method for preparing insoluble sulfur, in step (C), a mixture of the soluble sulfur liquid and the crude insoluble sulfur is solidified at 75-85° C. for 1-3 hours, and after washing, a carbon disulfide liquid containing soluble sulfur and powdered insoluble sulfur are obtained; the carbon disulfide liquid containing soluble sulfur is distilled to obtain carbon disulfide gas and a distillation kettle liquid; and the distillation kettle liquid is stripped to obtain sulfur.

[0018] The present invention also provides an apparatus for implementing the above-mentioned method for preparing insoluble sulfur, comprising a first mixer, a heater, a second mixer and a reactor connected in sequence.

[0019] Furthermore, the device also includes a distillation kettle, a condenser and a stripping tower; the distillation kettle is connected to the reactor, the distillation kettle is connected to the condenser, the distillation kettle is connected to the liquid sulfur recovery tank, the liquid sulfur recovery tank is connected to the stripping tower, and the stripping tower is connected to the condenser.

[0020] Furthermore, the device also includes a raw material tank, a liquid sulfur tank and a hydrogen sulfide injection device;

[0021] The raw material tank is connected to the liquid sulfur tank, and the liquid sulfur tank is connected to the first mixer;

[0022] The stripping tower is connected to the raw material tank;

[0023] The hydrogen sulfide injection device is connected to the first mixer.

[0024] Furthermore, the device also includes a mother liquor storage tank, which is connected to the reaction kettle, and the mother liquor storage tank is connected to the distillation kettle.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] The method for preparing insoluble sulfur provided by the present invention comprises the steps of mixing liquid sulfur and hydrogen sulfide gas, heating and cracking, rapid cooling, solidification, washing, drying, distillation, stripping, and sulfur recycling. The method effectively improves the conversion rate of insoluble sulfur and the thermal stability of the product, with a primary conversion rate of 55% to 58%, and the thermal stability of the prepared insoluble sulfur at 120°C is 64% to 68%. Furthermore, since hydrogen sulfide exists in a gaseous form, no other stabilizer is added during the entire preparation process, and the remaining sulfur that is not converted into the product can be recycled after distillation and stripping, thereby achieving energy conservation and environmental protection and reducing production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0028] Figure 1 Schematic diagram of the device of the present invention.

[0029] Reference numerals

[0030] 1-Raw material tank; 11-Liquid sulfur tank; 12-Metering pump;

[0031] 2-Hydrogen sulfide injection device; 3-First mixer; 4-Heater;

[0032] 5-second mixer; 6-reactor; 71-mother liquor storage tank;

[0033] 72-new liquid storage tank; 81-stillation kettle; 82-condenser;

[0034] 83-Liquid sulfur recovery tank; 84-Stripping tower. DETAILED DESCRIPTION

[0035] The technical scheme of the present invention will be clearly and completely described below in conjunction with the accompanying drawings and specific embodiments, but it will be understood by those skilled in the art that the following described embodiments are part of embodiments of the present invention, rather than all embodiments, and are only used to illustrate the present invention, and should not be considered as limiting the scope of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of the present invention. Those who do not specify specific conditions in the embodiments are carried out according to normal conditions or the conditions recommended by the manufacturer. Those whose reagents or instruments are not specified by the manufacturer are conventional products that can be purchased commercially.

[0036] The following is a detailed description of a method and apparatus for preparing insoluble sulfur according to an embodiment of the present invention.

[0037] In some embodiments of the present invention, a method for preparing insoluble sulfur is provided, comprising the following steps:

[0038] (A) Liquid sulfur and hydrogen sulfide gas are mixed and cracked at 500-550°C;

[0039] (B) After the cracking reaction, a mixture of sulfur and carbon disulfide is added and cooled to obtain an insoluble sulfur crude product and a sulfur-soluble liquid;

[0040] (C) solidifying a mixture of the soluble sulfur solution and the crude insoluble sulfur at 75-85° C. for 1-3 hours, washing, and drying to obtain the insoluble sulfur.

[0041] The method for preparing insoluble sulfur of the present invention comprises the steps of mixing liquid sulfur and hydrogen sulfide gas, heating and cracking, rapid cooling, solidification, washing, drying and the like; the method effectively improves the conversion rate of insoluble sulfur and the thermal stability of the product; the primary conversion rate can reach 55% to 58%, and the thermal stability of the prepared insoluble sulfur at 120°C is 65% to 68%.

[0042] During the cracking reaction of the present invention, active free radicals generated by the cracking of hydrogen sulfide are efficiently mixed with single sulfur atoms cracked by sulfur, and the active free radicals and sulfur atoms are fully mixed; during the cooling process, low-temperature carbon disulfide is used to quench the high-temperature liquid gaseous sulfur, and the active free radicals generated by the hydrogen sulfide are combined with S- to form a capping agent to obtain an insoluble sulfur crude product.

[0043] Since hydrogen sulfide is highly efficient as a pre-stabilizer, it forms free radicals HS- and H- at high temperatures, which combine with S- to form a stable structure H-[S]. n -H, which is higher than the stable structure CH3-[S] generated by all current post-stabilizers n-CH3, and in the distillation process, carbon disulfide can be recycled after condensation in the gas phase. The liquid phase does not contain organic matter. Pure sulfur can be obtained after flash evaporation in the stripping tower and can be directly used as raw material.

[0044] In some embodiments of the present invention, in step (A), the temperature of the cracking reaction is 450-600°C; typically but not limitatively, for example, the temperature of the cracking reaction is 450°C, 480°C, 500°C, 520°C, 550°C, 580°C or 600°C, etc.

[0045] In some embodiments of the present invention, in step (A), the mass ratio of liquid sulfur to hydrogen sulfide gas is 1:0.0005-0.0015; preferably, the mass ratio of liquid sulfur to hydrogen sulfide gas is 1:0.0009-0.0011; more preferably, the mass ratio of liquid sulfur to hydrogen sulfide gas is 1:0.001. The liquid sulfur is liquid sulfur.

[0046] In some embodiments of the present invention, in step (B), the temperature of the mixture of sulfur and carbon disulfide is 57-63°C; typically but not limiting, for example, the temperature of the mixture of sulfur and carbon disulfide is 57°C, 58°C, 59°C, 60°C, 61°C, 62°C or 63°C, etc.

[0047] In some embodiments of the present invention, in step (B), the mixture of sulfur and carbon disulfide is mainly obtained by mixing carbon disulfide at a temperature of 15-20°C and sulfur at a temperature of 450-600°C; preferably, the mixture of sulfur and carbon disulfide is mainly obtained by mixing carbon disulfide at a temperature of 15-20°C and sulfur at a temperature of 480-520°C.

[0048] In some embodiments of the present invention, in step (C), the mass ratio of the dissolved sulfur liquid to the insoluble crude sulfur product is 1.8 to 2.2:1; typically but not limitatively, for example, the mass ratio of the dissolved sulfur liquid to the insoluble crude sulfur product is 1.8:1, 1.9:1, 2:1, 2.1:1 or 2.2:1, etc.; preferably, the mass ratio of the dissolved sulfur liquid to the insoluble crude sulfur product is 2:1.

[0049] In the preparation method of insoluble sulfur of the present invention, a soluble sulfur liquid and an insoluble sulfur crude product are obtained after cooling, the soluble sulfur liquid and the insoluble sulfur crude product are solidified at a mass ratio of 1.8 to 2.2:1, and the excess soluble sulfur liquid is distilled and then recycled.

[0050] In some embodiments of the present invention, in step (C), after solidification, liquid carbon disulfide containing soluble sulfur and powdered insoluble sulfur are obtained by washing.

[0051] In some embodiments of the present invention, in step (C), washing comprises: mixing carbon disulfide, and obtaining carbon disulfide containing soluble sulfur and powdered insoluble sulfur after solid-liquid separation.

[0052] In some embodiments of the present invention, in step (C), the drying temperature is 80-90°C.

[0053] In some embodiments of the present invention, in step (C), a mixture of soluble sulfur liquid and crude insoluble sulfur is solidified at 75-85° C. for 1-3 hours, and after washing, carbon disulfide liquid containing soluble sulfur and powdered insoluble sulfur are obtained; the carbon disulfide liquid containing soluble sulfur is distilled to obtain carbon disulfide gas and still liquid; the still liquid is stripped to obtain sulfur; the obtained sulfur can be used as a raw material; preferably, the carbon disulfide gas is condensed to obtain carbon disulfide liquid; the carbon disulfide liquid can be used for cooling extraction in step (B).

[0054] In the preparation method of the present invention, since hydrogen sulfide exists in a gaseous state, no other stabilizer is added to the entire system. During the distillation process, the sulfur at the bottom of the kettle can meet the raw material usage standard, but contains a trace amount of carbon disulfide, which needs to be stripped. After the residual carbon disulfide is stripped, the sulfur is returned to the raw material storage tank and can be used as a raw material for preparing insoluble sulfur. After cooling, the carbon disulfide enters the storage tank for recycling, eliminating the need for a complex and harsh sulfur recovery process, thereby reducing the raw material cost.

[0055] See also Figure 1 The present invention also provides an apparatus for implementing the above-mentioned method for preparing insoluble sulfur, comprising a first mixer 3, a heater 4, a second mixer 5 and a reactor 6 connected in sequence.

[0056] In some embodiments of the present invention, the device further includes a distillation kettle 81, a liquid sulfur recovery tank 83, a condenser 82 and a stripping tower 84. The distillation kettle 81 is connected to the reactor 6, the distillation kettle 81 is connected to the condenser 82, the distillation kettle 81 is connected to the liquid sulfur recovery tank 83, the liquid sulfur recovery tank 83 is connected to the stripping tower 84, and the stripping tower 84 is connected to the condenser 82; preferably, a submersible pump is provided in the liquid sulfur recovery tank 83.

[0057] In some embodiments of the present invention, the device further comprises a raw material tank 1, a liquid sulfur tank 11 and a hydrogen sulfide injection device 2;

[0058] The raw material tank 1 is connected to the liquid sulfur tank 11; the liquid sulfur tank 11 is connected to the first mixer 3;

[0059] The stripping tower 84 is connected to the raw material tank 1;

[0060] The hydrogen sulfide injection device 2 is connected to the first mixer 3 .

[0061] In some specific embodiments of the present invention, a flow pump 12 is provided between the liquid sulfur tank 11 and the first mixer 3 .

[0062] In some specific embodiments of the present invention, a submersible pump is provided in the raw material tank 1 .

[0063] In some embodiments of the present invention, the device further includes a mother liquid storage tank 71 , which is connected to the second mixer 5 .

[0064] In some embodiments of the present invention, the device also includes a new liquid storage tank 72, which is connected to the mother liquid storage tank 71; the new liquid storage tank 72 is connected to the condenser 82; preferably, both the new liquid storage tank 72 and the mother liquid storage tank 71 are provided with a submersible pump.

[0065] In some specific embodiments of the present invention, the method for preparing insoluble sulfur using the above-mentioned device comprises the following steps:

[0066] (1) Liquid sulfur in the liquid sulfur tank 11 is transported to the first mixer 3 by the metering pump 12, and hydrogen sulfide gas in the hydrogen sulfide injection device 2 is transported to the first mixer 3 for efficient mixing to obtain a liquid-gas mixture. In the first mixer 3, the mass ratio of liquid sulfur to hydrogen sulfide gas is 1:0.0005-0.0015;

[0067] (2) The liquid-gas mixture in the first mixer 3 enters the heater 4, is heated to 500-550°C, and undergoes a cracking reaction in the heater 4 to produce active free radicals and sulfur atoms;

[0068] (3) After the cracking reaction, the material in the heater 4 is transported to the reactor 6 via the second mixer 5, and then a mixture obtained by mixing sulfur at a temperature of 500-550° C. and carbon disulfide at a temperature of 15-20° C. (the temperature of the mixture is controlled at 57-63° C.) is sprayed into the reactor 6 via the second mixer 5 to obtain insoluble sulfur crude product and dissolved sulfur liquid;

[0069] (4) The soluble sulfur liquid and the crude insoluble sulfur product are retained in the reactor 6 at a mass ratio of 1.8 to 2.2:1, and after solidification at 75 to 85° C. for 1 to 3 hours, washed. The obtained carbon disulfide liquid containing soluble sulfur is discharged from the liquid outlet of the reactor 6 into the mother liquid storage tank 71 through a filter screen, leaving powdered insoluble sulfur; the powdered insoluble sulfur is dried by continuously passing hot water at 80 to 90° C. into the heating jacket of the reactor 6;

[0070] (5) The carbon disulfide liquid containing carbon disulfide in the mother liquid storage tank 71 is transported to the distillation kettle 81 via a submersible pump. The distillation kettle 81 is heated using a 130-160°C steam coil. The gas phase outlet of the distillation kettle 81 is connected to the inlet of the condenser 82. The gas phase is condensed into liquid carbon disulfide and enters the new liquid carbon disulfide storage tank 72 for recycling. The liquid phase outlet of the distillation kettle 81 flows through the height difference gravity to the liquid sulfur recovery tank 83. The liquid sulfur recovery tank 83 is transported to the stripping tower 84 via a submersible pump. After flash evaporation at a temperature controlled at 160-180°C, the liquid phase of the stripping tower 84 flows to the raw material tank 1 by gravity. The gas phase of the stripping tower 84 is cooled to 20-30°C by the condenser 82. The liquid carbon disulfide flows by gravity into the new liquid storage tank 72 for recycling.

[0071] Example 1

[0072] The method for preparing insoluble sulfur provided in this embodiment comprises the following steps:

[0073] (1) Liquid sulfur in the liquid sulfur tank 11 is transported to the first mixer 3 by the metering pump 12, and hydrogen sulfide gas in the hydrogen sulfide injection device 2 is transported to the first mixer 3 for efficient mixing to obtain a liquid-gas mixture. In the first mixer 3, the mass ratio of liquid sulfur to hydrogen sulfide gas is 1:0.001;

[0074] (2) The liquid-gas mixture in the first mixer 3 enters the heater 4, is heated to 500-550°C, and undergoes a cracking reaction in the heater 4 to produce active free radicals and sulfur atoms;

[0075] (3) After the cracking reaction, the material in the heater 4 is transported to the reactor 6 via the second mixer 5, and then a mixture obtained by mixing sulfur at a temperature of 500-550° C. and carbon disulfide at a temperature of 15-20° C. (the temperature of the mixture is controlled at 57-63° C.) is sprayed into the reactor 6 via the second mixer 5 to obtain insoluble sulfur crude product and dissolved sulfur liquid;

[0076] (4) The soluble sulfur liquid and the crude insoluble sulfur product are retained in the reactor 6 at a mass ratio of 2:1, solidified at 75-85° C. for 2-3 hours, and then washed. The obtained carbon disulfide liquid containing soluble sulfur is discharged from the liquid outlet of the reactor 6 into the mother liquid storage tank 71 through a filter screen, leaving powdered insoluble sulfur; the powdered insoluble sulfur is dried by continuously passing hot water at 80-90° C. into the heating jacket of the reactor 6;

[0077] (5) The carbon disulfide liquid containing carbon disulfide in the mother liquid storage tank 71 is transported to the distillation kettle 81 through a submerged pump. The distillation kettle 81 is heated by a 130-160°C steam coil. The gas phase outlet of the distillation kettle 81 is connected to the inlet of the condenser 82. The gas phase is condensed into liquid carbon disulfide and enters the new liquid carbon disulfide storage tank 72 for recycling. The liquid phase outlet of the distillation kettle 81 flows through the height difference to the liquid sulfur recovery tank 83. The liquid sulfur recovery tank 83 is transported to the stripping tower 84 through a submerged pump. After flash evaporation at a temperature controlled at 160-180°C, the liquid phase of the stripping tower 84 flows to the raw material tank 1 by gravity. The gas phase of the stripping tower 84 is cooled to 20-30°C by the condenser 82. The liquid carbon disulfide flows by gravity into the new liquid storage tank 72 for recycling.

[0078] Example 2

[0079] The preparation method of insoluble sulfur provided in this embodiment is similar to that of Example 1, except that, in step (2), the temperature is raised to 550-600°C.

[0080] Comparative Example 1

[0081] The preparation method of insoluble sulfur provided in this comparative example refers to Example 1, with the only difference being that, in step (3), after the cracking reaction, the material in the heater is transported to the reactor 6 via the second mixer 5, and then the mixture obtained by mixing olefins, alkanes and carbon disulfide (20±5°C) (the temperature of the mixture is controlled at 57-63°C) is sprayed into the reactor 6 via the second mixer 5 to obtain crude insoluble sulfur and dissolved sulfur liquid.

[0082] The liquid sulfur after distillation in this comparative example contains organic matter and cannot be reused. It is treated as solid waste, which greatly affects the cost of insoluble sulfur.

[0083] Test Example 1

[0084] The method for preparing insoluble sulfur in Example 1 was used to continuously produce 10 batches of insoluble sulfur, and the results are shown in Table 1. The method for preparing insoluble sulfur in Comparative Example 1 was used to continuously produce 10 batches of insoluble sulfur, and the results are shown in Table 2.

[0085] Heating loss: Before sampling, the weighing bottle should be kept at a constant weight of 80℃ (or 105℃) for 2 hours (must be ready at all times), weigh with the lid on, and record the data (W0). After sampling, weigh and record the data (W1). Stagger the lid, dry at 80℃ for 30 minutes, take out and cool slightly, place a heat insulation board on the electronic balance, peel the bottle and weigh it again, record the data as W2, and calculate it.

[0086] IS content: Weigh 5g of sample to an accuracy of 0.0001g and place it into a 200ml stoppered Erlenmeyer flask. Add 50ml of carbon disulfide, cover the flask, and stir with a magnetic stirrer at 25℃±5℃ for 5min±1min. Dry a G4 sintered glass funnel in an 80℃±2℃ oven for 1h. Place the funnel in a desiccator and cool it to 25℃±5℃. Weigh the sample to an accuracy of 0.0001g. Filter through a funnel. Wash the flask and funnel with 20ml of carbon disulfide five times, draining the funnel as dry as possible on the last wash. Dry the funnel in an oven at 80℃±2℃ for 1h. Place the funnel in a desiccator and cool it to 25℃±5℃. Weigh the sample to an accuracy of 0.0001g.

[0087] 105°C / 15 min Stability: Fill a glass tube with 30 ml of mineral oil and a magnetic stirrer. Place the tube in an oil bath at 105°C ± 0.2°C, immersing at least 10 cm, with the center of the tube above the magnetic stirrer. Stir. Add the weight of the sample to a weighing spoon, accurate to 0.0001 g. After the tube has been placed in the oil bath for 15 min ± 5 s, quickly pour the sulfur sample into the oil and weigh the weighing spoon again, accurate to 0.0001 g. After 15 min ± 5 s, remove the tube from the oil bath and immediately place it in an ice-water bath, stirring for approximately 1 min. Add 50 ml of carbon disulfide and stir the tube on a magnetic stirrer for 3 min. Bake a G4 sintered glass funnel in an oven at 80°C ± 2°C for at least 1 hour. Cool the funnel in a desiccator to 25°C ± 5°C (approximately 30 min) and weigh to the nearest 0.0001 g. Filter the mixture in the glass tube on a funnel, and wash the glass tube, stirring rod and funnel with 20 ml of carbon disulfide. Repeat this process 5 times. Drain the funnel as dry as possible for the last wash. Dry it in an oven at 80°C ± 2°C for 1 hour, cool it to 25°C ± 5°C in a desiccator (approximately 30 minutes), and weigh it to an accuracy of 0.0001 g.

[0088] 120°C / 15 min Stability: Fill a glass tube with 30 ml of mineral oil and a magnetic stirrer. Place the tube in an oil bath at 120°C ± 0.2°C, immersing at least 10 cm, with the center of the tube above the magnetic stirrer. Stir. Add the weight of the sample to a weighing spoon, accurate to 0.0001 g. After the tube has been placed in the oil bath for 15 min ± 5 s, quickly pour the sulfur sample into the oil and weigh the weighing spoon again, accurate to 0.0001 g. After 15 min ± 5 s, remove the tube from the oil bath and immediately place it in an ice-water bath, stirring for approximately 1 min. Add 50 ml of carbon disulfide and stir the tube on a magnetic stirrer for 3 min. Bake a G4 sintered glass funnel in an oven at 80°C ± 2°C for at least 1 hour. Cool the funnel to 25°C ± 5°C in a desiccator (approximately 30 min) and weigh to the nearest 0.0001 g. Filter the mixture in the glass tube on a funnel, and wash the glass tube, stirring rod and funnel with 20 ml of carbon disulfide. Repeat this process 5 times. Drain the funnel as dry as possible for the last wash. Dry it in an oven at 80°C ± 2°C for 1 hour, cool it to 25°C ± 5°C in a desiccator (approximately 30 minutes), and weigh it to an accuracy of 0.0001 g.

[0089] Acidity: Use bromothymol blue indicator to determine the endpoint (HG / T2525-2011: indicator endpoint method): Weigh 10g sample (accurate to 0.001g), add it to a 500ml glass beaker with 15ml of anhydrous ethanol, stir well to fully moisten the sample, then add 200ml of water, stir well for 2-3min, let it stand for 5min, add 10 drops of bromothymol blue indicator solution (take 0.1g bromothymol blue, add 100ml of anhydrous ethanol to dissolve it, shake well, and obtain it), and titrate with sodium hydroxide titrant (0.02ml / L) until the solution turns blue-green, which is the endpoint.

[0090] Table 1

[0091]

[0092]

[0093] Table 2

[0094]

[0095] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing insoluble sulfur, characterized in that: An apparatus employing a method for preparing insoluble sulfur; The device comprises a first mixer, a heater, a second mixer and a reactor connected in sequence; The device further comprises a distillation kettle, a liquid sulfur recovery tank, a condenser and a stripping tower; the distillation kettle is connected to the reactor, the distillation kettle is connected to the condenser, the distillation kettle is connected to the liquid sulfur recovery tank, the liquid sulfur recovery tank is connected to the stripping tower, and the stripping tower is connected to the condenser; The device further comprises a raw material tank, and the stripping tower is connected to the raw material tank; The method for preparing the insoluble sulfur comprises the following steps: (A) Liquid sulfur and hydrogen sulfide gas are mixed and cracked at 500-550°C; The mass ratio of the liquid sulfur to the hydrogen sulfide gas is 1:0.001; (B) After the cracking reaction, a mixture of sulfur and carbon disulfide is added and cooled to obtain an insoluble sulfur crude product and a sulfur-soluble liquid; In step (B), the temperature of the mixture of sulfur and carbon disulfide is 57-63° C.; In step (B), the mixture of sulfur and carbon disulfide is mainly obtained by mixing carbon disulfide at a temperature of 15 to 20° C. and sulfur at a temperature of 450 to 600° C.; (C) solidifying the mixture of the soluble sulfur liquid and the crude insoluble sulfur at 75-85° C. for 2-3 hours, washing to obtain a carbon disulfide liquid containing soluble sulfur and powdered insoluble sulfur; distilling the carbon disulfide liquid containing soluble sulfur to obtain carbon disulfide gas and still liquid; and stripping the still liquid to obtain sulfur; In step (C), the mass ratio of the sulfur-dissolving liquid to the insoluble sulfur crude product is 2:

1.

2. The method for preparing insoluble sulfur according to claim 1, wherein The device also includes a liquid sulfur tank and a hydrogen sulfide injection device; The raw material tank is connected to the liquid sulfur tank, and the liquid sulfur tank is connected to the first mixer; The hydrogen sulfide injection device is connected to the first mixer.

3. The method for preparing insoluble sulfur according to claim 1, characterized in that: The device further comprises a mother liquor storage tank, wherein the mother liquor storage tank is connected to the reaction kettle, and the mother liquor storage tank is connected to the distillation kettle.

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