阅读说明：本技术 不溶性硫磺制备过程中水中硫磺粉的分离与萃取方法 (Method for separating and extracting sulfur powder in water in insoluble sulfur preparation process ) 是由 王延臻 段红玲 宋春敏 张安 高丽 张珩锴 于 2019-08-12 设计创作，主要内容包括：不溶性硫磺制备过程中水中硫磺粉的分离与萃取方法,其特征在于将水和粗品不溶性硫磺粉形成的浆液用泵打到分离罐中,分离罐中加有萃取溶剂,硫磺颗粒沉降进入溶剂中,然后用泵将溶剂和硫磺颗粒混合物打入萃取塔上部,将溶剂用泵打到萃取塔下部,萃取塔顶部流出的溶剂一部分返回分离罐,一部分经蒸发回收溶剂并得到可溶硫,萃取塔底流出的不溶性硫磺和溶剂加入稳定剂,然后过滤、蒸发回收溶剂并得到提纯后的不溶性硫磺。(A method for separating and extracting sulfur powder in water in the process of preparing insoluble sulfur is characterized in that slurry formed by water and crude insoluble sulfur powder is pumped into a separation tank by a pump, an extraction solvent is added into the separation tank, sulfur particles are settled and enter the solvent, then the mixture of the solvent and the sulfur particles is pumped into the upper part of an extraction tower by the pump, the solvent is pumped into the lower part of the extraction tower by the pump, one part of the solvent flowing out of the top of the extraction tower returns to the separation tank, one part of the solvent is evaporated to recover the solvent and obtain soluble sulfur, the insoluble sulfur flowing out of the bottom of the extraction tower and the solvent are added with a stabilizing agent, and then the solvent is filtered and evaporated to recover the solvent and obtain purified insoluble sulfur.)

1. The method for separating and extracting sulfur powder in water in the insoluble sulfur preparation process is characterized by comprising the following steps:

(1) crushing the insoluble sulfur crude product in water to obtain slurry, pumping the slurry into a separation tank by a pump, wherein the lower part of the separation tank is an extraction solvent layer, and the upper part of the separation tank is a water layer, and the insoluble sulfur particles in the water are sunk into the solvent;

(2) purifying and refining the insoluble sulfur by using an extraction tower, pumping the solvent and the insoluble sulfur particles at the lower part of the separation tank to the upper part of the extraction tower by using a pump, and pumping the solvent to the lower part of the extraction tower by using a pump;

(3) returning one part of the liquid flowing out of the top of the extraction tower to the separation tank, and heating and evaporating the other part of the liquid to recover the solvent and the sulfur;

(4) feeding insoluble sulfur and solvent from bottom of the extraction tower into a filter with stirring function, adding stabilizer, stirring for 10-120min, and filtering to separate out solvent;

(5) heating and evaporating the filtered insoluble sulfur to recover the solvent.

2. The process of claim 1, wherein the slurry of water and insoluble sulfur powder is pumped into a separation tank containing the extraction solvent after the crude insoluble sulfur is ground in water.

3. A method according to claim 1, characterized in that the solvent in the lower part of the separation tank is fed into the upper part of the extraction column together with the sulphur granules.

4. The method of claim 1, wherein a portion of the solvent exiting the top of the extraction column is returned to the knockout drum.

5. The method of claim 1, wherein a stabilizer is added to the solvent entering the extraction column in an amount of 1 to 10% by weight of the solvent.

Technical Field

The invention belongs to the field of nonmetallic elements and compounds thereof, and relates to a method for separating and extracting sulfur powder in water in the preparation process of insoluble sulfur. The international patent classification belongs to C01B 17/12.

Background

Insoluble Sulfur (IS) IS also called mu-type sulfur, which IS long-chain polymerized sulfur formed by ring-opening polymerization of ordinary sulfur and IS named because it IS Insoluble in carbon disulfide. The insoluble sulfur is mainly used as a vulcanizing agent of rubber, is widely used for the production of radial tires, has high dispersibility and high-temperature stability, can effectively avoid the blooming of rubber materials when used for rubber mixing, and has good vulcanizing effect. With the increasing demand for radial tires in China, the demand for insoluble sulfur is increasing day by day. The production of insoluble sulfur by using common sulfur has high economic benefit and social benefit.

At present, the preparation method of insoluble sulfur mainly comprises a contact method, a gasification method, a melting method and the like. The contact method is mainly a method for preparing insoluble sulfur products by taking hydrogen sulfide as a raw material and carrying out catalytic oxidation reaction in an acidic medium reactor. The gasification method and the melting method both take common sulfur as raw materials, and utilize the thermal activation ring-opening polymerization mechanism of the sulfur to prepare insoluble sulfur.

(1) Contact method

The contact method is with H₂S as a raw material, dependent on NO_x+Fe³⁺Method for producing insoluble sulfur by catalytic oxidation^[30]. The method comprises the following specific steps: high content of H₂S gas (concentration greater than 70%) and O₂Introducing HNO containing strong oxidant₃And FeCl₃The water solution generates insoluble sulfur under the oxidation-reduction action. The reaction mechanism for preparing insoluble sulfur by the contact method is as follows: h₂S in strong oxidant HNO₃And Fe³⁺Is partially oxidized to SO₃ ^2-And reduction product NO; SO (SO)₃ ^2-And H₂S reacts to generate insoluble sulfur, and O is introduced into reduction product NO₂Oxidation to NO₂，NO₂Followed by reaction with H₂S, reacting to generate insoluble sulfur; fe³⁺Is also reacted with H₂S reaction to generate insoluble sulfur and Fe²⁺In which Fe²⁺Is also NO₂Is oxidized into Fe³⁺Thereby realizing FeCl₃And recycling the aqueous solution.

Compared with the traditional method for producing insoluble sulfur, the contact method avoids the advantage of high-temperature corrosion of production equipment, and provides a new treatment H for petrochemical and coal chemical enterprises₂S waste gas. But H₂S is extremely toxic, has high requirement on the sealing property of production equipment, is difficult to realize large-scale production due to the limitation of an air source, has certain defects in the technology, and needs to be further explored and researched.

(2) Gasification process

The gasification method is that ordinary sulfur and a proper amount of stabilizer are mixed uniformly and added into a reactor, the reactor is placed in a closed tubular heating furnace for melting, the temperature is increased to 500-700 ℃, superheated sulfur vapor is sprayed into a cooling medium containing the stabilizer at a high speed by utilizing the pressure of the reactor for quenching, and plastic sulfur can be obtained. Since the polymerization reaction is reversible, after quenching, part of the polymerized sulfur is converted into soluble sulfur, so that the obtained plastic sulfur product is a mixture. Then the plastic sulfur is dried and solidified at a certain temperature, and then is dry-pulverized. To obtain a high insoluble sulphur product, CS is generally used₂Extracting the mixture with the solution, then carrying out suction filtration or centrifugal separation to remove the carbon disulfide serving as the extractant, and drying the remaining particles to obtain the product.

(3) Melting process

The most significant difference between the melting process and the gasification process is the difference in the state of the sulfur when it is quenched. Since the gasification method is a steam sulfur quench method and the melting method is a liquid sulfur quench method, the quench temperature is not as high as the temperature required for the gasification method. The specific operation process for preparing insoluble sulfur by the melting method comprises the following steps: heating sulfur to 160-300 deg.C, cooling with water to room temperature, separating water, drying and solidifying in air, and dry-pulverizing, grinding and filtering the obtained solid to obtain insoluble sulfur crude product.

The prepared insoluble sulfur is divided into two types, wherein one type is low-grade insoluble sulfur, namely insoluble sulfur which is not subjected to leaching and purification, wherein the content of the insoluble sulfur is only 50-60%, and the other type is high-grade insoluble sulfur, wherein the content of the insoluble sulfur reaches more than 90%. The industry generally adopts an extraction (also called leaching) method to purify insoluble sulfur, namely carbon disulfide is used to leach soluble sulfur in the insoluble sulfur to obtain high-grade insoluble sulfur.

Insoluble sulfur can make the sulfur powder fly upward in the use owing to stirring, high temperature, not only influences the production environment, also causes the danger of explosion, consequently for preventing flying upward of insoluble sulfur powder, the industrial oil filling type insoluble sulfur that uses is to fill the mineral oil that the flash point is high in the insoluble sulfur powder, reduces flying upward of dust.

Thus, the conventional insoluble sulfur production process includes: (1) quenching, namely heating the sulfur to 200-700 ℃, introducing the sulfur into quenching liquid for quenching to prepare viscoelastic insoluble sulfur, wherein water, aqueous solution and other solvents can be used as the quenching liquid in the quenching process; (2) drying and curing, drying and curing the viscoelastic insoluble sulfur at 40-80 ℃ for 3-15 hours to obtain a solid insoluble sulfur crude product, wherein the solid insoluble sulfur crude product contains 30-70% of insoluble sulfur; (3) crushing, namely crushing the insoluble sulfur crude product; (4) extracting, namely extracting and refining insoluble sulfur, and dissolving the unconverted soluble sulfur by an extracting agent; (5) filtering, drying, filtering the extractant to obtain wet insoluble sulfur, and evaporating the solvent to obtain dry insoluble sulfur, namely refined and purified insoluble sulfur; (6) oil-filled, and oil-filled insoluble sulfur is obtained.

Because the sulfur obtained after quenching is viscoelastic solid and needs to be solidified for a long time before being crushed, leached and purified, the production of insoluble sulfur in the industry at present adopts an intermittent production method, namely, the steps of quenching, solidification, crushing, leaching and purification, oil filling and the like are respectively carried out in different intermittent equipment. In the process of crushing sulfur, dry crushing is adopted at present, namely dried sulfur is crushed in a crusher, a large amount of dust is generated in the crushing process, the sulfur is flammable and the dust is explosive, so that the currently adopted dry crushing method is easy to cause fire and explosion, ignition and explosion caused by crushing almost exist in domestic and foreign insoluble sulfur production enterprises, a large amount of personnel and property losses are caused, and great risks are formed on social safety. Therefore, improving the production method of insoluble sulfur and reducing the explosion and fire risks are difficult problems for insoluble sulfur production enterprises. In addition, how to continue the production process is also a difficult problem for the insoluble sulfur production enterprises at present.

In the above steps, the subject group provides a method for crushing insoluble crude sulfur in water, which can reduce the risk of fire and explosion caused by the crushing process. The water temperature of the crushing process is controlled to be not higher than 80 ℃, and the insoluble sulfur is crushed into particles with the particle size of 50-400 meshes in a crusher to form slurry. However, in the method, water is crushed, so that insoluble sulfur and water need to be separated, separation equipment and difficulty are increased invisibly, water cannot exist in the extraction process of the insoluble sulfur as far as possible, otherwise, the extraction efficiency is reduced, and the stability of the product is influenced.

Disclosure of Invention

The invention aims to provide a method for separating and extracting sulfur powder in water in the preparation process of insoluble sulfur, which is used for the technical process of continuously producing the insoluble sulfur, improves the safety of the production process of the insoluble sulfur, reduces the fire and explosion risks, reduces the environmental pollution, reduces the labor intensity and improves the safety degree of the production process.

The method of the invention comprises the following steps:

(1) crushing the insoluble sulfur crude product in water to obtain slurry, pumping the slurry into a separation tank by a pump, wherein the lower part of the separation tank is an extraction solvent layer, and the upper part of the separation tank is a water layer, and the insoluble sulfur particles in the water are sunk into the solvent;

(2) purifying and refining the insoluble sulfur by using an extraction tower, pumping the solvent and the insoluble sulfur particles at the lower part of the separation tank to the upper part of the extraction tower by using a pump, and pumping the solvent to the lower part of the extraction tower by using a pump;

(3) returning one part of the liquid flowing out of the top of the extraction tower to the separation tank, and heating and evaporating the other part of the liquid to recover the solvent and the sulfur;

(4) feeding insoluble sulfur and solvent from bottom of the extraction tower into a filter with stirring function, adding stabilizer, stirring for 10-120min, and filtering to separate out solvent;

(5) heating and evaporating the filtered insoluble sulfur to recover the solvent.

In the above-described process, the extraction solvent used is CS₂And trichloroethylene. These two solvents are generally used alone or in combination, but CS is currently used₂Relatively many, CS₂The dissolving capacity to sulfur is strong, the recovery is easy, but the spontaneous combustion temperature is low, and the spontaneous combustion is easy; the trichloroethylene has moderate dissolving capacity, is not easy to self-ignite, but has high boiling point and high recovery temperature. Of course, other solvents may be used as the extraction solvent.

According to the method, the method is characterized in that after the insoluble sulfur crude product is crushed in water, water and insoluble sulfur powder are pumped into a separation tank by a pump, an extraction solvent is arranged in the separation tank, and because the density of sulfur is high, the density of water is smaller than the density of the solvent and the density of sulfur, sulfur (including insoluble sulfur) enters a solvent phase from a water phase through sedimentation, so that the crushed sulfur powder and water are not required to be filtered and separated, the separation of the sulfur powder and water can be realized by directly pumping sulfur water slurry into the separation tank by the pump, the separation is not thorough, a small amount of extremely fine sulfur powder exists in water, the yield of the process is not influenced, and the part of water can be pumped back to crushing equipment to be used as a crushing medium. The sulphur particles entering the solvent phase are pumped into an extraction plant for extraction operations, so that the process can be carried out continuously, avoiding the use of bulky and inefficient solids handling machinery.

The extraction tower is used as extraction equipment in the patent, and other types of extraction equipment such as an extraction reaction kettle, an extraction tank and the like can be used. The extraction tower structure canA conventional empty column is used, but a tray column with inclined trays (such as the one described in patent application 201710274172.1) can also be used. After the sulfur (including insoluble sulfur) and the solvent enter the extraction tower, the sulfur sinks into the extraction solvent due to the fact that the sulfur density is higher than that of the solvent, and sinks downwards along the extraction tower, and soluble sulfur contained in the sulfur is continuously dissolved by the extractant from bottom to top. Adding solvent into the lower part of the extraction tower, wherein CS can be used as solvent₂And trichloroethylene. These two solvents are generally used alone or in combination, but CS is currently used₂Is more. The proportion of the solvent and the insoluble sulfur entering the extraction tower needs to be adjusted according to the extraction effect, and CS is generally used₂In the case of a solvent, CS₂The ratio of the sulfur to crude insoluble sulfur is 6-12: 1 (mass ratio), which is much higher when trichloroethylene is used as solvent, and a minimum of 15: 1 (mass ratio). In order to improve the yield and stability of the insoluble sulfur, a stabilizer can be added into the solvent, and various organic stabilizers mentioned in the literature can be used as the stabilizer, and the amount of the stabilizer accounts for 1-10% of the weight of the solvent.

The solvent flowing out of the top of the extraction tower contains soluble sulfur, part of the solvent returns to the separation tank to maintain the boundary level of the separation tank, and the rest is heated and evaporated to recover the solvent and obtain the soluble sulfur. Thus, less solvent can be used, and the energy consumption for recovering the solvent is reduced.

The insoluble sulfur after extraction which flows out from the bottom of the extraction tower contains solvent, and the stability of the product can be improved by adding part of the stabilizer. The patent provides a filter with stirring, wherein a stabilizer is added into the filter, and the solvent is filtered and separated out after stirring for 10-120 min. Of course, the time can be longer, and the stabilizing effect is better. And then drying the filtered insoluble sulfur, wherein the drying process is heating and solvent evaporation, and the temperature in the solvent evaporation process cannot be higher than 80 ℃, otherwise, the high-temperature stability of the insoluble sulfur is reduced. Either atmospheric distillation or vacuum distillation may be used.

The method provided by the invention has the advantages that the extraction tower and the separation tank are used, so that the separation of the sulfur and the water is simple and easy, the extraction process can be continuously carried out, and the key production process of the whole insoluble sulfur can be continuous. The process that the crushing process of making easy to catch fire, exploding goes on in aqueous is implemented more easily, greatly reduced the probability that conflagration and explosion take place, simultaneously because crushing process goes on in aqueous, crushing temperature can be controlled through water yield and temperature, consequently can prevent because of the influence of the local high temperature that crushing process produced to insoluble sulphur high temperature stability, so insoluble sulphur high temperature stability through this kind of process production is better than traditional technology.

Drawings

Fig. 1 is a process flow diagram for the method. The following are the equipment and materials represented by the numbers in the figures.

1. A separation tank; 2. an extraction tower; 3. a buffer tank; 4. a pump; 5. a pump; 6. a pump; 7. a heat exchanger; 8. and (3) a filter.

Heating, quenching, drying and curing sulfur, crushing the sulfur in water, feeding the crushed slurry into a separation tank 1, pumping the slurry into the separation tank by a pump 4 to control the water temperature not to exceed 80 ℃, pumping the sulfur powder slurry into the upper part of an extraction tower 2 by a pump 5, pumping the solvent into the lower part of the extraction tower by a pump 6, feeding the solvent flowing out of the top of the extraction tower into a buffer tank 3, and evaporating the solvent at the bottom of the buffer tank 3 to recover the solvent to obtain soluble sulfur; the insoluble sulfur and the solvent flowing out of the bottom of the extraction tower enter a filter 8, a stabilizing agent is added, the mixture is filtered after being stabilized for a certain time, the filtered wet insoluble sulfur is heated and evaporated to recover the solvent, and dry insoluble sulfur is obtained, and oil-filled insoluble sulfur is obtained after oil is filled. The heat exchanger 7 can be used to reduce the heat generated during the comminution process and to prevent the water temperature from becoming too high.

ADVANTAGEOUS EFFECTS OF INVENTION

The insoluble sulfur is produced according to the method, so that the filtration separation of the sulfur and water is avoided, the continuous operation can be realized, the labor intensity of workers is reduced, and the obtained insoluble sulfur has stable quality and good stability. The production process can avoid the safety problems of explosion, fire and the like caused by sulfur crushing, and eliminates potential safety hazards.

Detailed Description

The process of the present invention is further illustrated below with reference to examples.