CN115159468B

CN115159468B - Method for preparing elemental sulfur by catalyzing bisulphite through sulfur deposited active carbon

Info

Publication number: CN115159468B
Application number: CN202110359241.5A
Authority: CN
Inventors: 崔泽星; 杨本涛; 魏进超
Original assignee: Zhongye Changtian International Engineering Co Ltd
Current assignee: Zhongye Changtian International Engineering Co Ltd
Priority date: 2021-04-02
Filing date: 2021-04-02
Publication date: 2023-12-29
Anticipated expiration: 2041-04-02
Also published as: CN115159468A

Abstract

The invention discloses a method for preparing elemental sulfur by catalyzing bisulphite with sulfur-deposited active carbon and a method for preparing the sulfur-deposited active carbon. The invention prepares sulfur deposition active carbon by vapor deposition method, then adopts the sulfur deposition active carbon as catalyst, and can realize catalytic disproportionation reaction of high concentration bisulphite at lower temperature. The active carbon and sulfur are cheap and easy to obtain, and the prepared sulfur deposition active carbon can be recycled. Therefore, the catalyst for the disproportionation reaction of the bisulphite by using the sulfur deposited active carbon has wide market prospect and economic benefit.

Description

Method for preparing elemental sulfur by catalyzing bisulphite through sulfur deposited active carbon

Technical Field

The invention relates to a method for preparing elemental sulfur by catalyzing bisulphite, in particular to a method for preparing elemental sulfur by catalyzing bisulphite by sulfur deposition activated carbon, and belongs to the technical field of bisulphite catalytic disproportionation.

Background

At present, the sulfur deposition activated carbon is sulfur-containing activated carbon prepared by adopting high-quality activated carbon as base carbon and adopting a special process, and is mainly used for mercury removal in mercury-containing gas mercury removal devices such as natural gas/coal gas and the like. Chinese patent document CN111675215a discloses sulfur-deposited activated carbon materials, and methods of making and using the same. Mixing tetrahydrofuran, sulfur-containing solid heterocyclic organic matter, transition metal salt and a silicon dioxide template, and removing a solvent to obtain a blocky sample; grinding into powder particles, and carbonizing in inert atmosphere to obtain carbonized product; and finally removing the silicon dioxide template in the carbonized product and the metal salt on the surface of the carbonized product to obtain the sulfur-deposited active carbon material. The specific surface area of the sulfur deposited active carbon material is 1000-2000m ² And/g, wherein the sulfur content of the sulfur deposited activated carbon material is 10-20 wt% based on the total weight of the sulfur deposited activated carbon material. The sulfur deposition active carbon material has higher sulfur content (10-20%), larger specific surface area and better adsorption effect on mercury simple substance; and the sulfur deposition activated carbon has betterStability, can lengthen the life cycle.

Chinese patent document CN112079355a discloses a sulfur-rich activated carbon and a preparation method thereof, which is activated by uniformly mixing petroleum coke, an activator, sulfide and sulfite; then, the activated product is contacted with acid gas to react to obtain a solid-phase product; and finally, washing and drying the solid-phase product to obtain the sulfur-enriched active carbon. The prepared sulfur-rich activated carbon product has the advantages of large specific surface area, high sulfur dispersion uniformity, good mercury removal effect, simple preparation method and the like.

Sulfur is an oxygen group simple substance nonmetallic solid, is an important chemical raw material, and is widely used for producing various chemical products, gunpowder, matches, pigments and medicinal products. Powdered sulfur is agriculturally useful as an insecticide and bactericide. Sulfur is mainly derived from natural sulfur deposit extraction and recovery of sulfur from natural gas, coal gas and industrial waste gas. With the expansion of sulfur demand, the recovery of sulfur from waste gas or wastewater is becoming an important source of sulfur.

The liquid phase disproportionation sulfur production method is to utilize the characteristic that sulfur element in bisulphite is in an intermediate valence state, and disproportionation is carried out under the conditions of high temperature and catalyst, so that the recovery of elemental sulfur is realized. For example, in chinese patent document 200710035059.4, it is reported that sodium sulfide is used to absorb sulfur dioxide to obtain sodium bisulphite, and then the sodium bisulphite reacts at 120 to 240 ℃ to obtain elemental sulfur. In order to further reduce the reaction temperature, chai Liyuan et al report chinese patent document 201210391355.9 and chinese patent document 201210392392.1, which disclose that the use of elemental selenium to catalyze the disproportionation of bisulphite realizes that elemental sulfur is recovered under liquid phase conditions at 80-100 ℃. Furthermore, liu Hui et al report chinese patent document 201711078170.1, which discloses that recovery of elemental sulfur is achieved under normal temperature and pressure conditions by utilizing synergistic effects of light irradiation and iodide ions. But is not suitable for large-scale production and application at present because selenium and iodine are expensive. Disproportionation of bisulphite by catalytic means to recover sulphur is a low cost operation. However, the process has not been widely popularized due to the high price of the catalyst. It is therefore of great importance to find a low cost, high efficiency bisulphite disproportionation catalyst. In the prior art, there is no report on the use of sulfur-deposited activated carbon for catalyzing the disproportionation reaction of bisulphite.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a method for preparing elemental sulfur by catalyzing bisulphite with sulfur deposited active carbon. The invention adopts sulfur deposited active carbon as catalyst, and can realize the disproportionation reaction of high-concentration bisulphite at about 50 ℃. The simple substance sulfur and the active carbon are both simple and easily obtained cheaper substances, the reaction condition is mild, and the prepared sulfur deposition active carbon can be recycled. Therefore, the catalyst for the disproportionation reaction of the bisulphite by using the sulfur deposited active carbon has wide market prospect and economic benefit.

In order to achieve the above purpose, the technical scheme adopted by the invention is as follows:

a method for preparing elemental sulfur by catalyzing bisulphite with sulfur deposited active carbon, which comprises the following steps:

1) Firstly, the bisulphite is completely dissolved, then sulfur deposition active carbon is added for disproportionation reaction, and the pH value of the reaction system is continuously monitored until the pH value changes to a pH set value. Then solid-liquid separation is carried out to obtain filtrate.

2) And returning the sulfur deposition active carbon with solid-liquid separation to the step 1) for recycling. And (3) continuously carrying out heating reaction on the filtrate after solid-liquid separation to obtain elemental sulfur.

Preferably, the sulfur-deposited activated carbon is prepared by the following method:

a) And respectively placing elemental sulfur and active carbon into different heating sections, and then introducing protective gas.

B) The heating section containing elemental sulfur is heated to produce sulfur vapor.

C) And C), heating the heating section with the active carbon, and then introducing sulfur vapor generated in the step B) to carry out vapor deposition reaction, so as to obtain the sulfur deposition active carbon after the reaction is completed.

Preferably, in step 1), the bisulphite is one or more of sodium bisulphite salt, potassium bisulphite salt and ammonium bisulphite salt.

Alternatively, the sulfite is an acidic solution of one or more of sodium sulfite, potassium sulfite and ammonium sulfite, and the pH of the acidic solution is 2-5.5, preferably 3-5.

Preferably, in step 1), the temperature of the disproportionation reaction is 40-80 ℃, preferably 45-70 ℃, more preferably 50-60 ℃.

Preferably, in step 1), the disproportionation reaction is carried out for a period of time ranging from 0.3 to 10 hours, preferably from 0.5 to 8 hours, more preferably from 0.8 to 5 hours.

Preferably, in step 1), the pH set point is < 3, preferably the pH set point is < 2.5, more preferably the pH set point is < 2.

Preferably, in step 2), the temperature of the heating reaction is 50-120 ℃, preferably 60-110 ℃, more preferably 70-100 ℃.

Preferably, in the step a), the activated carbon is one or more of coal activated carbon, wood activated carbon, coconut activated carbon, and fruit shell activated carbon, preferably coal activated carbon.

The mass ratio of the elemental sulfur to the active carbon is 1.5-18:1, preferably 3-15:1, and more preferably 4.5-12:1.

Preferably, the activated carbon is powdered activated carbon or granular activated carbon.

Preferably, in step a), the protective gas is one or more of nitrogen, argon and helium, preferably nitrogen.

Preferably, in step B), the temperature after heating in the heating section with elemental sulphur is 400-600 ℃, preferably 450-550 ℃.

Preferably, in step C), the temperature after heating in the heating section with activated carbon is 60-180deg.C, preferably 80-150deg.C.

Preferably, the sulfur-carrying amount per gram of the activated carbon in the sulfur-deposited activated carbon is 1.6 to 16g, preferably 3.2 to 9.6g, more preferably 4.8 to 8g.

Preferably, the step 1) specifically comprises: the bisulphite is first completely dissolved or the sulfite is completely dissolved and then added with acid (preferably sulfurous acid) to adjust the pH to 2-5.5 (preferably pH 3-5). Then adding sulfur deposited active carbon, heating to 40-80 deg.C (preferably 50-60 deg.C) for disproportionation reaction for 0.3-10 hr (preferably 0.5-8 hr). The pH value of the reaction system is continuously monitored, and when the pH value of the system is lower than 3 (preferably, the pH value is lower than 2), the sulfur deposition activated carbon is filtered and separated, and filtrate is obtained.

Preferably, the step 2) specifically comprises: and (3) drying the sulfur deposition activated carbon with solid-liquid separation and returning to the step 1) for recycling. The filtrate after solid-liquid separation is continuously heated to 50-120 ℃ (preferably 70-100 ℃) to react until sulfur precipitation is generated. And separating out sulfur precipitate and drying to obtain elemental sulfur.

Preferably, the step A) comprises the following steps: according to the flow direction of the gas stream, elemental sulfur and activated carbon are sequentially placed in different heating sections of a heater (e.g., a staged heating reactor), and then a protective gas (e.g., nitrogen) is introduced at a rate of 0.05 to 1.0L/min (preferably 0.1 to 0.5L/min).

Preferably, the step B) specifically comprises: after a period of nitrogen is introduced (preferably after the nitrogen has exhausted the air in the heater). The heating section with elemental sulfur is heated (preferably to 400-600 c) until sulfur vapor is generated.

Preferably, the step C) is specifically: the heating section with the activated carbon is heated (preferably, the heating section with the activated carbon is heated to 60-180 ℃). And then the sulfur vapor generated in the step B) is introduced into a heating section containing active carbon for vapor deposition reaction, and the reaction time is 1-5h (preferably 2-3 h) to obtain the sulfur deposited active carbon.

At present, sulfur mainly comes from ore deposit extraction of natural sulfur and recovery of sulfur from natural gas, coal gas and industrial waste gas. With the expansion of sulfur demand, the recovery of sulfur from waste gas or wastewater is becoming an important source of sulfur. The liquid phase disproportionation sulfur production method is characterized in that the characteristic that the sulfur element in the bisulphite is in an intermediate valence state is utilized, and the disproportionation is carried out under the conditions of high temperature (for example, the temperature at which the bisulphite directly carries out disproportionation reaction is more than 160 ℃) and a catalyst, so that the recovery of elemental sulfur is realized. For example, in chinese patent document 200710035059.4, it is reported that sodium sulfide is used to absorb sulfur dioxide to obtain sodium bisulphite, and then the sodium bisulphite reacts at 120 to 240 ℃ to obtain elemental sulfur. In order to further reduce the reaction temperature, chai Liyuan et al report chinese patent document 201210391355.9 and chinese patent document 201210392392.1, which disclose that the use of elemental selenium to catalyze the disproportionation of bisulphite realizes that elemental sulfur is recovered under liquid phase conditions at 80-100 ℃. Furthermore, liu Hui et al report chinese patent document 201711078170.1, which discloses that recovery of elemental sulfur is achieved under normal temperature and pressure conditions by utilizing synergistic effects of light irradiation and iodide ions. But is not suitable for industrial mass production and application at present because selenium and iodine are expensive.

Further, the sulfur-deposited activated carbon is sulfur-containing activated carbon prepared by adopting high-quality activated carbon as base carbon and adopting a special process, and is mainly used for mercury removal in mercury-containing gas mercury removal devices such as natural gas/coal gas and the like. In the invention, elemental sulfur is adsorbed and loaded on the activated carbon by a vapor deposition method to obtain sulfur-deposited activated carbon. The method comprises the steps of firstly, respectively placing elemental sulfur and active carbon into different heating sections of a sectional heater according to the flow direction of the airflow, and then introducing protective gas (such as nitrogen). After the protective gas has evacuated the air in the heater, the heated section containing elemental sulfur is heated to 400-600℃ (preferably 450-550℃) until sulfur vapor is produced, while the heated section containing activated carbon is heated to 60-180℃ (preferably 80-150℃) for vapor deposition adsorption. In this process, the protective gas continuously transports sulfur vapor generated in the heating section containing elemental sulfur into the heating section containing activated carbon. Through the adsorption of the activated carbon powder or activated carbon particles, the sulfur vapor is subjected to vapor deposition on the surface of the activated carbon at 60-180 ℃. In the vapor deposition process, the active carbon carrier has developed gaps, so that sulfur vapor can be fully and uniformly loaded into the pore channels of the active carbon to form the sulfur deposition active carbon. The specific reaction formula is as follows:

sulfur deposition active carbon synthesis: S+AC→S@AC. (AC means activated carbon)

In the invention, the activated carbon is one or more of coal activated carbon, wood activated carbon, coconut activated carbon and fruit activated carbon, and is preferably coal activated carbon. Preferably in the form of powder (activated carbon powder) or granules (activated carbon granules).

In the invention, the protective gas is one or more of nitrogen, argon and helium, and is preferably nitrogen. The flow rate of the protective gas is 0.05 to 1.0L/min (preferably 0.1 to 0.5L/min). The elemental sulfur and activated carbon are heated separately after the protective gas has exhausted the air inside the heater. The protective gas is used for protecting, and air is required to be exhausted before heating, so that the aim is to prevent harmful substances generated by reaction with oxygen in the process of heating elemental sulfur to generate sulfur vapor. It should be noted that heating the heating section with elemental sulfur to 400-600 c and heating the heating section with activated carbon to 60-180 c are performed simultaneously. The purpose is to ensure that sulfur vapor can be better and uniformly deposited in the gaps of the active carbon at a proper temperature, so as to obtain the sulfur-deposited active carbon with excellent catalytic effect.

In the present invention, a bisulphite solution is completely obtained by dissolving bisulphite, which ionizes into hydrogen ions and sulfite ions in a solvent. Then under the catalysis of sulfur deposition active carbon, hydrogen ions and sulfite ions are subjected to catalytic disproportionation reaction. I.e., the bisulphite can undergo disproportionation reaction under the catalysis of sulfur-deposited active carbon at a temperature of 40-80 ℃ (preferably 50-60 ℃), and the S (IV) is disproportionated into S (0) and S (VI). The pH of the solution will always decrease during this reaction. When the pH of the solution is reduced to below 3 (preferably to below 2), the catalyst is filtered and separated (the separated sulfur deposited active carbon catalyst can be recycled after being dried), so that the input cost of the catalyst is greatly reduced. The residual solution is sulfur colloid, and the heating reaction (such as heating to 50-120 ℃ for reaction, preferably heating to 70-100 ℃ for reaction) is continued to destabilize the sulfur colloid, and finally sulfur particles are formed. Separating out sulfur particle precipitate and drying to obtain elemental sulfur.

Further, a sulfite solution is obtained by dissolving sulfite, and then an acid (preferably sulfurous acid) is added to adjust the pH of the solution to 2 to 5.5 (preferably pH 3 to 5) so that a large amount of hydrogen ions and sulfite ions are present in the sulfite solution. Then under the catalysis of sulfur deposition active carbon, hydrogen ions and sulfite ions are subjected to catalytic disproportionation reaction. I.e. bisulphite, disproportionates S (IV) into S (0) and S (VI) under the catalytic action of sulfur-deposited activated carbon. The pH of the solution will always decrease during this reaction. When the pH of the solution is reduced to below 3 (preferably to below 2), the catalyst is filtered and separated (the separated sulfur-carrying catalyst can be recycled after being dried), so that the investment cost of the catalyst is greatly reduced. The residual solution is sulfur colloid, and the heating reaction (such as heating to 50-120 ℃ for reaction, preferably heating to 70-100 ℃ for reaction) is continued to destabilize the sulfur colloid, and finally sulfur particles are formed. Separating out sulfur particle precipitate and drying to obtain elemental sulfur. The reaction process for disproportionation of S (IV) into S (0) and S (VI) is shown below:

catalytic disproportionation with sulfur deposited activated carbon as catalyst:

in the present invention, sulfur-deposited activated carbon is added to a bisulfite solution (or an acidic solution of sulfite) and the reaction temperature is controlled to be about 50 ℃ for a period of time until the solution becomes pale yellow. Filtering to separate sulfur deposited active carbon, and continuing the reaction of the residual filtrate at 70-100 ℃ until sulfur deposition is generated and clear supernatant is obtained, namely the reaction is finished.

In the present invention, the sulfur loading per gram of activated carbon is the sulfur content per unit mass of activated carbon in the sulfur-deposited activated carbon after passing through the embodiments provided herein. I.e., the mass ratio of sulfur to activated carbon in the sulfur-deposited activated carbon.

In the invention, the bisulphite is one or more of sodium bisulphite salt, potassium bisulphite salt and ammonium bisulphite salt. The bisulphite can also be one or more of sodium sulfite, potassium sulfite and ammonium sulfite, and the pH of the solution is regulated to be 2-5.5 (preferably 3-5) by using sulfurous acid.

Compared with the prior art, the invention has the following beneficial technical effects:

1. the invention adopts the vapor deposition method to deposit sulfur in the active carbon, and utilizes the vapor of sulfur to generate vapor deposition on the surface of the active carbon at 60-180 ℃ and has stronger adsorption effect on the active carbon particles. So that the elemental sulfur heat energy is fully and uniformly loaded into the pore canal of the active carbon to form sulfur deposition active carbon. Namely, the sulfur-deposited active carbon with excellent catalytic performance is prepared under normal temperature and normal pressure by simple process conditions.

2. The sulfur deposition active carbon agent synthesized by the invention is used as a catalyst for the disproportionation reaction of the bisulfites (or the acidic solution of the sulfites), and has the advantages of low price, wide sources, easy separation and recovery and long service life compared with the existing catalyst. And the sulfur deposition active carbon is used as a catalyst, so that elemental sulfur can be prepared and recovered at a lower temperature (about 50 ℃), the engineering application prospect is wide, and the method has great economic benefit.

3. The invention creatively adopts sulfur-deposited active carbon as a catalyst for the disproportionation reaction of bisulphite (including but not limited to a system containing hydrogen ions and sulfite ions) to realize the low-temperature catalytic disproportionation. Provides a new approach for the research of the disproportionation reaction of the bisulphite.

Drawings

FIG. 1 is a flow chart for the preparation of elemental sulfur using bisulfite catalysis.

FIG. 2 is a flow chart for the preparation of elemental sulfur using sulfite catalysis.

FIG. 3 is a flow chart of the preparation of sulfur-deposited activated carbon.

Detailed Description

The following examples illustrate the technical aspects of the invention, and the scope of the invention claimed includes but is not limited to the following examples.

Example 1

40g of elemental sulfur was added to the front section of the segmented heater, and then 10g of activated carbon particles (average particle size 75 μm) were added to the rear section of the segmented heater. Then, nitrogen was passed through at a rate of 0.1L/min for 5-10min. Then heating the front section of the sectional heater containing elemental sulfur to 450 ℃, and simultaneously heating the rear section of the sectional heater containing active carbon to 120 ℃; and (3) communicating the front section and the rear section of the sectional heater for vapor deposition reaction for 2h, and drying to obtain the sulfur deposition activated carbon I.

Example 2

40g of elemental sulfur was added to the front section of the segmented heater, and then 10g of activated carbon particles (average particle size of 2 mm) were added to the rear section of the segmented heater. Then, nitrogen was passed through at a rate of 0.1L/min for 5-10min. Then heating the front section of the sectional heater containing elemental sulfur to 450 ℃, and simultaneously heating the rear section of the sectional heater containing active carbon to 120 ℃; and (3) connecting the front section and the rear section of the sectional heater for vapor deposition reaction for 3h, and drying to obtain the sulfur deposition activated carbon II.

Example 3

80g of elemental sulfur was added to the front section of the segmented heater, and then 10g of activated carbon particles (average particle size of 2 mm) were added to the rear section of the segmented heater. Then, nitrogen was passed through at a rate of 0.1L/min for 5-10min. Then heating the front section of the sectional heater containing elemental sulfur to 450 ℃, and simultaneously heating the rear section of the sectional heater containing active carbon to 120 ℃; and (3) connecting the front section and the rear section of the sectional heater for vapor deposition reaction for 4 hours, and drying to obtain sulfur deposition activated carbon III.

Example 4

40g of elemental sulfur was added to the front section of the segmented heater, and then 10g of activated carbon particles (average particle size 5 mm) were added to the rear section of the segmented heater. Then, nitrogen was passed through at a rate of 0.1L/min for 5-10min. Then heating the front section of the sectional heater containing elemental sulfur to 450 ℃, and simultaneously heating the rear section of the sectional heater containing active carbon to 120 ℃; and (3) connecting the front section and the rear section of the sectional heater for vapor deposition reaction for 3h, and drying to obtain the sulfur deposition activated carbon IV.

Example 5

30.0g of sodium bisulphite was dissolved in 100mL of water. Then 3.0g of sulfur-depositing activated carbon I was added and the temperature was raised to 55℃for reaction. And continuously monitoring the pH value of the reaction system, and filtering to separate sulfur deposition active carbon and obtain filtrate when the pH value of the system is lower than 2. The filtrate obtained was further heated to 90 ℃ for reaction until sulphur precipitation occurred and a relatively clear supernatant was obtained. Then, the sulfur precipitate was separated and dried to obtain elemental sulfur (2.80 g, yield 90.85%).

Example 6

30.0g of sodium bisulphite was dissolved in 100mL of water. Then 3.0g of sulfur-deposited activated carbon II was added and the temperature was raised to 55℃for reaction. And continuously monitoring the pH value of the reaction system, and filtering to separate sulfur deposition active carbon and obtain filtrate when the pH value of the system is lower than 2. The filtrate obtained was further heated to 90 ℃ for reaction until sulphur precipitation occurred and a relatively clear supernatant was obtained. The sulfur precipitate was then separated and dried to give elemental sulfur (2.54 g, yield 82.41%).

Example 7

30.0g of sodium bisulphite was dissolved in 100mL of water. Then 3.0g of sulfur-deposited activated carbon III was added and the temperature was raised to 55℃for reaction. And continuously monitoring the pH value of the reaction system, and filtering to separate sulfur deposition active carbon and obtain filtrate when the pH value of the system is lower than 2. The filtrate obtained was further heated to 90 ℃ for reaction until sulphur precipitation occurred and a relatively clear supernatant was obtained. The sulfur precipitate was then separated and dried to give elemental sulfur (2.73 g, yield 88.58%).

Example 8

37.8g of sodium sulfite was dissolved in 100mL of water, and the pH of the solution was adjusted to 3-5 by adding sulfurous acid. Then 3.0g of sulfur-deposited activated carbon II was added and the temperature was raised to 80℃for reaction. And continuously monitoring the pH value of the reaction system, and filtering to separate sulfur deposition active carbon and obtain filtrate when the pH value of the system is lower than 2. The filtrate obtained was further heated to 90 ℃ for reaction until sulphur precipitation occurred and a relatively clear supernatant was obtained. The sulfur precipitate was then separated and dried to give elemental sulfur (3.01 g, yield 93.89%).

Example 9

47.5g of potassium sulfite was dissolved in 100mL of water, and the pH of the solution was adjusted to 3-5 by adding sulfurous acid. Then 5.0g of sulfur-deposited activated carbon III was added and the temperature was raised to 70℃for reaction. And continuously monitoring the pH value of the reaction system, and filtering to separate sulfur deposition active carbon and obtain filtrate when the pH value of the system is lower than 2.5. The filtrate obtained was further heated to 90 ℃ for reaction until sulphur precipitation occurred and a relatively clear supernatant was obtained. The sulfur precipitate was then separated and dried to give elemental sulfur (2.73 g, yield 85.10%).

Example 10

46.4g of ammonium sulfite was dissolved in 100mL of water, and the pH of the solution was adjusted to 3-5 by adding sulfurous acid. Then 3.0g of sulfur-deposited activated carbon IV was added and the temperature was raised to 55℃for reaction. And continuously monitoring the pH value of the reaction system, and filtering to separate sulfur deposition active carbon and obtain filtrate when the pH value of the system is lower than 2.5. The filtrate obtained was further heated to 90 ℃ for reaction until sulphur precipitation occurred and a relatively clear supernatant was obtained. The sulfur precipitate was then separated and dried to give elemental sulfur (3.88 g, yield 90.84%).

Example 11

21.0g of sodium bisulphite and 12.6g of sodium sulfite are dissolved in 100mL of water, and the pH of the solution is adjusted to 3-5 by adding sulfurous acid. Then 3.0g of sulfur-deposited activated carbon II was added and the temperature was raised to 60℃for reaction. And continuously monitoring the pH value of the reaction system, and filtering to separate sulfur deposition active carbon and obtain filtrate when the pH value of the system is lower than 2. The filtrate obtained was further heated to 90 ℃ for reaction until sulphur precipitation occurred and a relatively clear supernatant was obtained. The sulfur precipitate was then separated and dried to give elemental sulfur (2.85 g, 88.34% yield).

Example 12

21.0g of sodium bisulphite and 11.0g of ammonium sulphite are dissolved in 100mL of water and the pH of the solution is adjusted to 3-5 by adding sulphite. Then 3.0g of sulfur-deposited activated carbon II was added and the temperature was raised to 60℃for reaction. And continuously monitoring the pH value of the reaction system, and filtering to separate sulfur deposition active carbon and obtain filtrate when the pH value of the system is lower than 2. The filtrate obtained was further heated to 90 ℃ for reaction until sulphur precipitation occurred and a relatively clear supernatant was obtained. The sulfur precipitate was then separated and dried to give elemental sulfur (2.90 g, yield 91.48%).

Example 13

19.8g of ammonium bisulfate and 11.0g of ammonium sulfite are dissolved in 100mL of water, and the pH of the solution is adjusted to 3-5 by adding sulfurous acid. Then 3.0g of sulfur-deposited activated carbon II was added and the temperature was raised to 60℃for reaction. And continuously monitoring the pH value of the reaction system, and filtering to separate sulfur deposition active carbon and obtain filtrate when the pH value of the system is lower than 2. The filtrate obtained was further heated to 90 ℃ for reaction until sulphur precipitation occurred and a relatively clear supernatant was obtained. Then, the sulfur precipitate was separated and dried to obtain elemental sulfur (3.03 g, yield 96.25%).

Claims

1. A method for preparing elemental sulfur by catalyzing bisulphite with sulfur deposited active carbon is characterized by comprising the following steps: the method comprises the following steps:

1) Firstly, completely dissolving bisulphite, then adding sulfur deposition active carbon to perform disproportionation reaction, and continuously monitoring the pH value of a reaction system until the pH value changes to a pH set value; then carrying out solid-liquid separation to obtain filtrate; the temperature of the disproportionation reaction is 40-55 ℃;

2) Returning the sulfur deposition active carbon with solid-liquid separation to the step 1) for recycling; continuously carrying out heating reaction on the filtrate after solid-liquid separation to obtain elemental sulfur;

the sulfur-deposited activated carbon is prepared by the following method:

a) Respectively placing elemental sulfur and active carbon into different heating sections, and then introducing protective gas;

b) Heating the heating section containing elemental sulfur to generate sulfur vapor;

2. The method according to claim 1, characterized in that: in the step 1), the bisulphite is one or more of sodium bisulphite salt, potassium bisulphite salt and ammonium bisulphite salt.

3. The method according to claim 2, characterized in that: in the step 1), the disproportionation reaction time is 0.3-10h; and/or

The pH set value is less than 3; and/or

In step 2), the temperature of the heating reaction is 50-120 ℃.

4. A method according to claim 3, characterized in that: in the step 1), the disproportionation reaction time is 0.5-8h; and/or

The pH set value is less than 2.5; and/or

In step 2), the temperature of the heating reaction is 60-110 ℃.

5. The method according to claim 4, wherein: in the step 1), the disproportionation reaction time is 0.8-5h; and/or

The pH set value is less than 2; and/or

In step 2), the temperature of the heating reaction is 70-100 ℃.

6. The method according to claim 1, characterized in that: in the step A), the activated carbon is one or more of coal activated carbon, wood activated carbon, coconut activated carbon and fruit shell activated carbon;

the mass ratio of the elemental sulfur to the active carbon is 1.5-18:1.

7. The method according to claim 6, wherein: the activated carbon is coal activated carbon;

the mass ratio of the elemental sulfur to the active carbon is 3-15:1.

8. The method according to claim 7, wherein: the mass ratio of the elemental sulfur to the active carbon is 4.5-12:1.

9. The method according to any one of claims 6-8, characterized in that: the activated carbon is powdered activated carbon or granular activated carbon.

10. The method according to claim 1, characterized in that: in the step A), the protective gas is one or more of nitrogen, argon and helium; and/or

In the step B), the temperature of the heated section with elemental sulfur is 400-600 ℃; and/or

In the step C), the temperature of the heated section with the activated carbon is 60-180 ℃;

in the sulfur deposition active carbon, the sulfur carrying amount of each gram of active carbon is 1.6-16g.

11. The method according to claim 10, wherein: in the step A), the protective gas is nitrogen; and/or

In the step B), the temperature of the heated section with elemental sulfur is 450-550 ℃; and/or

In the step C), the temperature of the heated section with the activated carbon is 80-150 ℃;

in the sulfur deposition active carbon, the sulfur carrying amount of each gram of active carbon is 3.2-9.6g.

12. The method according to claim 11, wherein: in the sulfur deposition active carbon, the sulfur carrying amount of each gram of active carbon is 4.8-8g.

13. The method according to claim 1, characterized in that: the step 1) is specifically as follows: firstly, completely dissolving bisulphite; then adding sulfur deposition active carbon, heating to perform disproportionation reaction for 0.3-10h; and continuously monitoring the pH value of the reaction system, and filtering to separate sulfur deposition active carbon when the pH value of the system is lower than 3, so as to obtain filtrate.

14. The method according to claim 13, wherein: the step 1) is specifically as follows: firstly, completely dissolving bisulphite; then adding sulfur deposition active carbon, heating to perform disproportionation reaction for 0.5-8h; and continuously monitoring the pH value of the reaction system, and filtering to separate sulfur deposition active carbon when the pH value of the system is lower than 2, so as to obtain filtrate.

15. The method according to claim 1, characterized in that: the step 2) is specifically as follows: drying the sulfur deposition active carbon with solid-liquid separation and returning to the step 1) for recycling; continuously heating the filtrate after solid-liquid separation to 50-120 ℃ for reaction until sulfur precipitation is generated; and separating out sulfur precipitate and drying to obtain elemental sulfur.

16. The method according to claim 15, wherein: and continuously heating the filtrate after solid-liquid separation to 70-100 ℃ to react.

17. The method according to claim 1, characterized in that: the step A) comprises the following steps: according to the flow direction of the air flow, sequentially placing elemental sulfur and active carbon into different heating sections of a heater, and then introducing protective gas at the speed of 0.05-1.0L/min; and/or

The step B) is specifically as follows: introducing nitrogen for a period of time; the heating section with elemental sulfur is heated until sulfur vapor is produced.

18. The method according to claim 17, wherein: the step A) comprises the following steps: according to the flow direction of the air flow, sequentially placing elemental sulfur and active carbon into different heating sections of a sectional heating reactor, and then introducing nitrogen at the speed of 0.1-0.5L/min; and/or

The step B) is specifically as follows: after the nitrogen is exhausted from the air in the heater; the heating section with elemental sulfur is heated to 400-600 ℃ until sulfur vapor is produced.

19. The method according to claim 17 or 18, characterized in that: the step C) is specifically as follows: heating the heating section with the activated carbon; and then the sulfur vapor generated in the step B) is introduced into a heating section containing active carbon for vapor deposition reaction, wherein the reaction time is 1-5h, and the sulfur deposition active carbon is obtained.

20. The method according to claim 19, wherein: the step C) is specifically as follows: heating the heating section with the activated carbon to 60-180 ℃; and then the sulfur vapor generated in the step B) is introduced into a heating section containing active carbon for vapor deposition reaction, wherein the reaction time is 2-3h, and the sulfur deposited active carbon is obtained.