A method for strengthening, filtering and separating sulfur from metal sulfide slags and producing polymeric sulfur

Abstract

The application discloses a method for filtering and separating sulfur in metal sulfur residue and preparing polymerized sulfur, and the method comprises the following steps: pretreating the metal sulfur residue by acid immersion, water washing, dehydration and melting to obtain molten metal sulfur residue; adding viscosity regulators (thiazole substances and guanidine substances) into the molten metal sulfur residue, stirring and reacting, and then performing pressure filtration separation to obtain sulfur liquid; adding polymerization regulators (thiazole substances, thiuram substances, sulfenamide substances and guanidine substances) into the sulfur liquid to perform polymerization, and then adding polymerized sulfur capping agents to perform capping to obtain polymerized sulfur liquid; and cooling the polymerized sulfur liquid in ice water to obtain polymerized sulfur products. The method can realize viscosity reduction of the molten metal sulfur residue by using special viscosity regulators, improve the separation rate of sulfur and metal impurities in the metal sulfur residue, obtain high-purity sulfur liquid, and control liquid sulfur polymerization by using polymerized sulfur regulators to obtain high-molecular-weight polymerized sulfur products with high yield.

Description

TECHNICAL FIELD

[0001] The present application relates to a method for treating metal sulphur residue, in particular to a method for strengthening the filtration separation of sulphur in metal sulphur residue and preparing polymer sulphur, and belongs to the field of comprehensive recycling of non-ferrous smelting waste residue. BACKGROUND

[0002] In the non-ferrous smelting industry, a large amount of multi-metal sulphur residue will be produced with the large-scale exploitation of sulphide minerals. The sulphur and heavy metal impurities in such multi-metal sulphur residue have the characteristics of mixing and wrapping. Due to the limitations of technology, the traditional method mostly uses the method of stacking to treat such multi-metal sulphur residue. However, due to the high content of sulphur in multi-metal sulphur residue and the presence of a large amount of heavy metal ions, such multi-metal sulphur residue is mostly listed as hazardous waste. The method of stacking to treat multi-metal sulphur residue will bring great environmental risks, such as soil heavy metal pollution, SO2 pollution and serious environmental problems such as acid wastewater.

[0003] At present, the treatment methods for sulphur residue mainly include physical methods and chemical methods. The principle of the chemical method is to dissolve elemental sulphur and then separate sulphur and impurities. The physical method is to separate sulphur and heavy metal impurities by using the phase change of sulphur. However, the current methods have the disadvantages of high energy consumption and cost and strong toxicity of reagents, and cannot be applied on an industrial scale. The relatively mature method in the industry is to use the multi-step filtration method of flotation-thermal melting to separate sulphur and metal impurities. However, because the viscosity of molten multi-metal sulphur residue is large, the mass transfer resistance is large during pressure filtration, which makes it difficult to separate sulphur and metal impurities, not only affecting the separation rate and purity of sulphur, but also causing great difficulty in the subsequent efficient recovery of valuable metals in the filter residue. At the same time, the price of sulphur product is declining year by year. Considering the energy consumption cost and other problems, enterprises urgently need to find a method to increase the value of sulphur product.

[0004] Therefore, it is necessary to provide a method for strengthening the filtration separation of sulphur in metal sulphur residue to solve or at least alleviate the technical defects that sulphur and metal impurities are difficult to separate in the prior art, and to further develop the high-value technology of sulphur product. SUMMARY

[0005] In view of the technical problems that the sulphur in multi-metal sulphur residue polymerizes during the melting and holding process, resulting in large viscosity and low separation rate of sulphur and metal, the purpose of the present application is to provide a method for strengthening the filtration separation of sulphur in metal sulphur residue and preparing polymer sulphur. The method adds a special viscosity regulator to reduce the viscosity of molten metal sulphur residue, improve the separation rate of sulphur and heavy metal impurities in metal sulphur residue, and obtain high-purity sulphur liquid. On this basis, a polymer sulphur regulator is used to control the polymerization of liquid sulphur to obtain a high-molecular-weight polymer sulphur product with high yield.

[0006] In order to achieve the above technical purposes, the present application provides a method for strengthening the filtration separation of sulfur in metal sulfur residue and preparing polymerized sulfur, which comprises the following steps: pretreating the metal sulfur residue by acid leaching, water washing, dehydration and melting to obtain molten metal sulfur residue; adding a viscosity regulator into the molten metal sulfur residue and stirring to react, and then performing pressure filtration separation to obtain a sulfur liquid; adding a polymerization regulator into the sulfur liquid to perform polymerization, and then adding a polymerized sulfur capping agent to perform capping to obtain a polymerized sulfur liquid; and cooling the polymerized sulfur liquid in ice water to obtain a polymerized sulfur product.

[0007] The viscosity regulator comprises thiazole substances and guanidine substances.

[0008] The polymerized sulfur regulator comprises thiazole substances, thiuram substances, sulfenamide substances and guanidine substances.

[0009] The viscosity regulator used in the present application can effectively regulate the viscosity of the molten metal sulfur residue, and the viscosity regulator comprises thiazole substances and guanidine substances, wherein the thiazole substances can reduce the bond energy of S-S bonds by using the five-membered ring structure, and can induce the breaking of long-chain sulfur, so as to reduce the viscosity; at the same time, the thiazole ring has a strong coordination effect on metal ions, and can reduce the interaction force between metal ions and sulfur molecules, which is beneficial to the separation of metal impurities in sulfur; and the guanidine substances can stabilize the viscosity-reducing effect of the thiazole substances, and the combination of the two can effectively reduce the viscosity of the molten metal sulfur residue, improve the filtration separation effect, and improve the separation efficiency of metal impurities.

[0010] The polymerized sulfur regulator can effectively regulate the polymerization process of liquid sulfur to obtain a high-molecular-weight polymerized sulfur product, and the polymerized sulfur regulator comprises thiazole substances, thiuram substances, sulfenamide substances and guanidine substances, wherein the thiazole substances and the thiuram substances can promote the breaking of S-S bonds under the action of high temperature of liquid sulfur, and can produce a large amount of active sulfur radical components, induce the opening of the ring structure of short-chain cyclic octasulfur, and successively form long-chain macromolecular sulfur from a large number of open-ring short-chain sulfur; and the sulfenamide substances and the guanidine substances can stabilize the polymerization regulation effect of the thiazole substances and the thiuram substances, and the combination of the several substances can obtain a high-quality polymerized sulfur product.

[0011] As a preferred embodiment, the viscosity modifier comprises the following components by mass percentage: 80-98% thiazoles and 2-20% guanidines. The thiazoles are preferably at least one of 2-mercaptobenzothiazole, 2-amino-4-methylbenzothiazole, and dibenzothiazole disulfide. The guanidines are preferably diphenylguanidine. The thiazoles in the viscosity modifier contain a five-membered ring structure that can reduce the SS bond energy. They also contain thiol, amino, and disulfide groups that can induce the cleavage of long-chain sulfur compounds, making them the main active substances for reducing viscosity. A small amount of guanidine stabilizes the viscosity-reducing effect of the thiazoles. If the proportion of thiazoles relative to guanidines is too low, it is difficult to promote the SS bond cleavage to generate sufficient active sulfur free radicals to achieve the purpose of reducing viscosity and improving the separation efficiency of metal impurities. Conversely, if the proportion of thiazoles relative to guanidines is too high, it is difficult to stabilize the thiazole viscosity modifier.

[0012] As a preferred embodiment, the amount of viscosity modifier used is 0.005–0.020 mol / kg of the metal sulfur slag. If the proportion of viscosity modifier is too low, the viscosity reduction and separation enhancement effect will be insignificant; if the proportion of viscosity modifier is too high, the viscosity reduction will have the opposite effect, inducing polymerization and leading to an increase in viscosity.

[0013] As a preferred embodiment, the stirring reaction is carried out at a temperature of 140–150°C for 20–200 minutes. This preferred reaction temperature helps to ensure the reactivity of the viscosity modifier, thereby achieving better viscosity control.

[0014] As a preferred embodiment, the polymerization regulator comprises the following components by mass percentage: 59-75% thiazole compounds, 24-40% thiuram compounds, 0.05-3% sulfenamide compounds, and 0.05-3% guanidine compounds; wherein the thiazole compounds are benzothiazoles or a combination of benzothiazoles with thiazoles and / or 2-mercaptobenzothiazoles; the thiuram compounds are at least one of tetramethylthiuram disulfide, tetramethylthiuram monosulfide, and tetramethylpentamethylenethiuram tetrasulfide; the guanidine compounds are diphenylguanidines; and the sulfenamide compounds are N,N-dimethyl-2-benzothiazole sulfenamides. Thiazole compounds and thiuram compounds are the main components of the polymerization regulator. The thiazole compounds, containing a large number of thiazole rings, can reduce the bond energy of the octasulfide SS bond, promoting SS bond cleavage to generate a large number of active sulfur free radicals. Meanwhile, the active sulfur free radicals formed by the thiuram compounds at high temperatures can open the octasulfide ring and induce the formation of long-chain polymerized sulfur. Sulphamides and guanidines are auxiliary components that act as polymerization regulators to stabilize thiazoles and thiurams. If the ratio of sulfenamides and guanidines is too low, it will be difficult to obtain a large number of active sulfur radicals, thus affecting the formation of high molecular weight sulfur. If the ratio of thiazoles and thiurams is too low, the amount of active sulfur radicals produced will also be reduced, which is not conducive to the polymerization of small molecule liquid sulfur.

[0015] As a preferred embodiment, the mass of the polymerization regulator is 20-50% of the mass of the metallic sulfur slag. If the proportion of the polymerization regulator is too low, the degree of polymerization of the elemental sulfur polymer product will be insufficient; if the proportion of the polymerization regulator is too high, the sulfur purity will be too low, and economic costs will increase.

[0016] As a preferred embodiment, the polymerization conditions are: temperature of 145–165°C and time of 20–60 min.

[0017] As a preferred embodiment, the polymeric sulfur end-capping agent comprises the following components by mass percentage: 5-30% lauric acid, 10-50% oleic acid, and 20-80% iodine. Lauric acid, oleic acid, and iodine can all be used as polymeric sulfur end-capping agents, but using iodine as the main component, combined with appropriate amounts of lauric acid and oleic acid, can achieve a better end-capping effect.

[0018] As a preferred embodiment, the amount of the polymeric sulfur end-capping agent is 0.1 to 2 wt% of the mass of the metallic sulfur slag. If the amount of polymeric sulfur end-capping agent is too low, the end-capping performance will be poor, resulting in a decrease in the degree of polymerization of the polymeric sulfur; if the amount of polymeric sulfur end-capping agent is too high, it will affect the purity of elemental sulfur, and the new substances formed by the polymerization between end-capping agents will affect the purity of the polymeric sulfur product.

[0019] As a preferred embodiment, the end-capping conditions are: a reaction at a temperature of 145–165°C for 5–30 minutes.

[0020] As a preferred embodiment, the metallic sulfur slag contains sulfur, iron, and heavy metal elements. The heavy metal elements include at least one of Zn and Pb, and may also contain copper, etc. The main components and their mass content in the metallic sulfur slag are: S > 65%, Fe < 10%, Zn < 10%, Pb < 3%. The strong interaction between metallic impurities and sulfur makes separation difficult, resulting in low sulfur recovery rates, which is the primary problem this invention aims to solve.

[0021] As a preferred embodiment, the acid leaching conditions are: a temperature of 45–100°C and an acid solution pH of 1–4. Acid leaching can leach out metal ions, reducing their impact on the subsequent melting and hot pressing process.

[0022] As a preferred embodiment, the moisture content of the dehydrated metallic sulfur slag is <12wt%.

[0023] As a preferred embodiment, the melting conditions are: a temperature of 150–155°C and a melting time of 60–180 min.

[0024] As a preferred embodiment, the pressure applied during the pressure filtration process is 0.6–0.8 MPa. The filter screen used in the pressure filtration has a filter diameter ≤0.5 μm.

[0025] As a preferred embodiment, the polymerized sulfur solution is poured into an ice-water mixture and stirred for 10–30 minutes. The preferred temperature range of the ice-water mixture is -20°C to 5°C.

[0026] Compared with the prior art, the technical solution of the present invention has at least the following advantages:

[0027] 1. To address the technical challenge of high viscosity and low separation rate of sulfur and metal caused by the polymerization of molten sulfur during the heat preservation process in the coarse sulfur tank, this invention achieves viscosity reduction of molten metal sulfur slag by adding a special viscosity regulator, which can reduce the viscosity by more than 90% and improve the separation efficiency of metal impurities and sulfur.

[0028] 2. This invention develops a new synthesis method for polymerized sulfur products, which directly obtains polymerized sulfur products by bulk polymerization of the separated sulfur liquid, resulting in high yield and large molecular weight, effectively improving the value of separated sulfur products.

[0029] 3. Compared with existing solvent methods, the method of separating sulfur liquid from metal sulfur slag in this invention significantly reduces the cost of chemical solvents and avoids the use of highly toxic organic solvents in experiments. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the content shown in these drawings without creative effort.

[0031] Figure 1 This is a schematic flowchart of the method for enhancing the filtration and separation of sulfur in metallic sulfur slag according to the present invention.

[0032] Figure 2 The images show the polymerized sulfur products generated in Examples 1, 2, and 3 of this invention, where a, b, and c are the polymerized sulfur products of Examples 1 to 3, respectively.

[0033] Figure 3 The images show the Raman diagrams of the polymerized sulfur product and sublimed sulfur generated in Example 1 of this invention. Detailed Implementation

[0034] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0036] When numerical ranges are given in the embodiments, it should be understood that, unless otherwise stated in the present invention, both endpoints of each numerical range and any value between the two endpoints may be selected. Unless otherwise defined, all technical and scientific terms used in this invention, as well as the prior art known to those skilled in the art and the description of this invention, may be implemented using any prior art methods, devices, and materials similar to or equivalent to those described, used, or made of materials in the embodiments of this invention.

[0037] Those skilled in the art should understand that non-ferrous metal sulfides are important sources of metal and sulfur resources. However, during mining and smelting, large amounts of pollutants containing various heavy metals such as lead, mercury, and copper are generated, causing significant environmental harm; among these, sulfur-containing heavy metal hazardous waste is particularly difficult to treat. Sulfur is easily oxidized, which may lead to equipment corrosion or SO2 pollution during subsequent treatment; furthermore, the binding forms of sulfur and heavy metal ions are diverse, posing significant challenges to the recovery of valuable metal ions and the separation of toxic metal ions. Therefore, resource recovery is an important means of treating and disposing of sulfur-containing heavy metal hazardous waste. When heavy metals are encapsulated in sulfur, how to separate the heavy metals from the sulfur is the key issue for achieving resource recovery and also a challenge faced in the treatment of sulfur-containing heavy metal hazardous waste.

[0038] Based on this, in order to effectively separate heavy metals (metal impurities) and sulfur in metal sulfur slag, the present invention provides a method for enhanced sulfur filtration and separation in metal sulfur slag, comprising the following steps:

[0039] S1 provides molten metal sulfur slag, which contains metal impurities (including metal elements) and sulfur (S).

[0040] It should be noted that the metal sulfur slag can be a polymetallic sulfur slag, that is, the metal elements in the metal impurities can be multiple; the metal impurities shown can contain heavy metal elements, that is, the metal elements in the metal impurities can include or be heavy metal elements, and there can be multiple heavy metal elements; the metal elements can include or be one or more of Fe, Zn, and Pb; of course, the metal elements can also include or be other heavy metal elements such as Hg and Cu, which will not be listed here.

[0041] In this invention, sulfur (S) refers to the element S existing in the form of S8, the form of Fe includes or is FeS2, the form of Zn includes or is ZnS, and the form of Pb includes or is PbSO4; in addition to the above substances, the metal sulfur slag may also contain CaSO4.

[0042] The metallic sulfur slag, by mass fraction, comprises: sulfur (S) > 65%, Fe < 10%, Zn < 10%, and Pb < 3%. Specifically, the S content can be 65%–95%, the Fe content can be 1%–10%, the Zn content can be 0.1%–10%, and the Pb content can be 0.05%–3%.

[0043] It should be emphasized that since the sulfur element in sulfur-containing substances such as FeS2, ZnS, PbSO4, and CaSO4 does not exist in the form of sulfur, the proportion of sulfur (S) can be excluded from the calculation.

[0044] In this invention, the molten metal sulfur slag provided may include or be:

[0045] S11, the solid metal sulfur slag (before melting) is subjected to impurity removal treatment, water washing treatment and dehydration treatment in sequence.

[0046] The impurity removal process includes: acid leaching the metal sulfur slag at a temperature of 45–100°C, using an acid solution with a pH of 1–4; the acid solution may include one or more of dilute hydrochloric acid and dilute sulfuric acid, with the specific concentration determined by the pH.

[0047] Specifically, the process can be as follows: the metal sulfur slag is added to an acid solution, and the temperature is raised to 45-100°C to effectively leach out the impurities in the polymetallic sulfur slag, thereby obtaining the metal sulfur slag after acid washing and impurity removal.

[0048] The water washing treatment is a conventional method, which only requires washing the metallic sulfur slag until it is neutral or close to neutral, and will not be described in detail here.

[0049] The dehydration treatment includes: dehydrating the metal sulfur slag that has undergone the water washing treatment to make the moisture content of the metal sulfur slag <12%.

[0050] Specifically, the process can be as follows: the metal sulfur slag after the water washing treatment is filtered and dehydrated through a vacuum belt filter to obtain dehydrated sulfur slag with a moisture content of <12%.

[0051] S12, the dehydrated metallic sulfur slag is melted to obtain molten metallic sulfur slag; wherein the melting temperature can be 150-155℃ and the melting time can be 60-180min.

[0052] Specifically, the process can be as follows: the dehydrated metallic sulfur slag is fed into a crude sulfur melting hydrocyclone via a belt conveyor. The temperature inside the crude sulfur melting hydrocyclone is 150-155°C, and the holding time inside the crude sulfur melting hydrocyclone is 60-180 minutes to ensure that the metallic sulfur slag is completely melted. After melting, the molten metallic sulfur slag is discharged from the bottom of the crude sulfur melting hydrocyclone into a crude sulfur pool for subsequent steps in step S2.

[0053] S2, a viscosity modifier is mixed into the molten metal sulfur slag to obtain a molten slag to be separated; the amount of the viscosity modifier added relative to the metal sulfur slag is 0.005 to 0.020 mol / kg.

[0054] The viscosity modifier, by mass fraction, comprises or consists of: 80-98% thiazoles and 2-20% guanidines; the total mass fraction of the viscosity modifier is 100%.

[0055] The thiazoles may include at least one of 2-mercaptobenzothiazole, 2-amino-4-methylbenzothiazole, and dibenzothiazole disulfide, and the guanidines include diphenylguanidine.

[0056] The process of mixing a viscosity modifier into the molten metal sulfur slag may include: adding the viscosity modifier into the molten metal sulfur slag, stirring at a temperature of 140–150°C, and maintaining the temperature for 20–60 minutes.

[0057] The addition of a viscosity modifier to the molten metal sulfur slag may further include: stirring the molten metal sulfur slag at a temperature of 140–150°C and holding it at that temperature for 30–200 min before adding the viscosity modifier to the molten metal sulfur slag.

[0058] The specific steps of mixing the viscosity modifier into the molten metal sulfur slag can be as follows: after the molten metal sulfur slag is discharged from the bottom of the crude sulfur melting hydrocyclone into the crude sulfur pool, it is stirred at a temperature of 140-150°C (stirring speed can be <500 rpm) and kept at this temperature for 20-60 min; then, a sulfur viscosity modifier is added, and the mixture is stirred at a temperature of 140-150°C (stirring speed can be <500 rpm) and kept at this temperature for 30-200 min to obtain viscosity-reducing sulfur slag (molten slag to be separated).

[0059] S3, the molten residue to be separated is filtered to obtain metal filter residue and separated sulfur liquid, wherein the sulfur liquid is high-purity sulfur.

[0060] The filter diameter for the filtration separation can be ≤0.50μm, specifically 0.10~0.50μm; the filtration separation can be pressure filtration, that is, during the filtration separation process, a pressure of 0.6~0.8MPa can be applied to the residue to be separated; during the filtration separation process, the temperature of the residue to be separated can be maintained at 140~150℃.

[0061] The specific steps for filtering and separating the molten residue to be separated can be as follows: pumping the molten residue to be separated into a filter press in batches; and then filtering the sulfur liquid (high-purity sulfur liquid) obtained in the filter press.

[0062] S4, a polymerization regulator is mixed into the separated sulfur liquid to obtain a molten polymerized sulfur regulating liquid; the amount of the polymerization regulator added is 20-50 wt% of the metal sulfur slag.

[0063] The polysulfide regulator, by mass fraction, comprises or consists of: 59-75% thiazoles, 24-40% thiurams, 0.05-3% sulfenamides, and 0.05-3% guanidines; the total mass fraction of the polysulfide regulator is 100%. The thiazoles in the polysulfide regulator are preferably benzothiazoles or a combination of benzothiazoles and thiazoles and / or 2-mercaptobenzothiazoles. The thiurams are preferably at least one of tetramethylthiuram disulfide, tetramethylthiuram monosulfide, and bis(pentamethylenethiuram) tetrasulfide. The guanidines are preferably diphenylguanidine. The sulfenamides are preferably N,N-dimethyl-2-benzothiazole-sulfenamides.

[0064] The process of mixing the polymerization regulator into the molten metal sulfur slag may include: adding the polymerization regulator into the molten metal sulfur slag, stirring at a temperature of 145–165°C, and holding at that temperature for 20–60 minutes.

[0065] S5, a polysulfide end-capping agent is mixed into the molten polysulfide control liquid, and then the molten polysulfide liquid is dripped into ice water to obtain the polysulfide product; the amount of the end-capping agent added is 0.01 to 0.5 wt% of the separated sulfur liquid.

[0066] The process of mixing the polymeric sulfur end-capping agent into the molten metal sulfur slag includes: adding 0.1-2 wt% of the polymeric sulfur end-capping agent into the molten metal sulfur slag, then stirring at a temperature of 145-165°C and maintaining the temperature for 5-30 minutes.

[0067] In the process of polymer sulfur end-capping, the polymer sulfur end-capping agent is lauric acid, oleic acid and iodine, and the lauric acid in the polymer sulfur end-capping agent is 5-30%, the oleic acid is 10-50% and the iodine is 20-80%.

[0068] The temperature range of the ice-water mixture is -20℃ to 5℃;

[0069] The polymerized sulfur in step S5 is granulated to obtain the polymerized sulfur product.

[0070] It is worth noting that this invention addresses the challenges of high viscosity, low separation efficiency, and declining value of sulfur products during the molten filtration separation of sulfur and metal impurities in polymetallic sulfur slag. It provides a method that, during the melting of polymetallic sulfur slag, a sulfur viscosity regulating agent breaks down the long-chain polymeric sulfur molecules, forming small-molecule cyclic octasulfides that are easily separated by pressure filtration. After separation, a polymeric sulfur regulating agent is added to the high-purity sulfur solution to induce ring-opening polymerization of elemental sulfur, forming a high-value polymeric sulfur product. This invention's method is simple, easy to operate, and has good processing results. It effectively reduces the viscosity of the molten sulfur slag during the hot filtration stage, achieving efficient separation and recovery of sulfur and metal sulfides. It comprehensively utilizes valuable metals and sulfur resources in hazardous waste and, through the chemical regulation of high-value polymeric sulfur products, offers significant economic benefits.

[0071] Specifically, this invention first pre-treats the metallic sulfur slag with acid washing to remove impurities. The removed metallic sulfur slag is then washed with water until the pH value is neutral. Subsequently, the metallic sulfur slag is dehydrated (moisture content <12%). The dehydrated metallic sulfur slag is then fed into a melting hydrocyclone. The temperature in the crude sulfur melting hydrocyclone is maintained at 150–155°C. After the metallic sulfur slag melts for 60–180 minutes, it is pumped into a crude sulfur tank and continuously heated and stirred. The temperature in the crude sulfur tank is maintained at 140–150°C, with simultaneous stirring. This heating and stirring is carried out for 30 minutes… After 200 minutes, a viscosity modifier is added and stirring is continued for another 20-60 minutes. During this process, the viscosity modifier breaks down the large-molecule long-chain polymeric sulfur, forming small-molecule cyclic octasulfides that are easier to filter, thus enhancing the separation of sulfur from metallic impurities and reducing the viscosity of the molten metallic sulfur slag. After viscosity reduction, the slag to be separated is pressurized and hot-filtered. Then, a polymeric sulfur control reagent is added to the high-purity sulfur solution obtained from the separation, and after heat preservation, a polymeric sulfur end-capping agent is added. The solution is then poured into ice water and granulated to obtain the polymeric sulfur product. Therefore, this invention can effectively reduce the viscosity of metallic sulfur slag during molten filtration, achieving efficient separation and recovery of metallic impurities such as metal sulfides from sulfur, reducing the stockpiling of metallic sulfur slag, and obtaining high-value polymeric sulfur products through reagent control.

[0072] The technical solutions provided by the present invention will be described in detail below with reference to specific examples, but they should not be construed as limiting the scope of protection of the present invention.

[0073] Example 1

[0074] A method for enhancing the filtration and separation of sulfur from metallic sulfur slag includes the following steps:

[0075] 1. Using polymetallic sulfur slag (No. 1 polymetallic sulfur slag) as raw material, its main components are: S 81wt%, Zn 2wt%, Fe 2wt%, Pb 0.55wt%, and others 14.45wt%. Here, the percentage refers to the proportion of the phase containing the element. For example, S represents SO (sulfur), Zn represents ZnS, ZnSO4, etc., Fe represents FeS2, FeSO4, etc., and Pb represents PbSO4, etc. The percentages thereafter will not be elaborated.

[0076] Dilute sulfuric acid was added to the polymetallic sulfur slag at a liquid-to-solid volume ratio of 5L:1kg, the pH was adjusted to 3, and the temperature was raised to 50℃. After stirring for 30 minutes to remove most of the soluble metal sulfates and other substances, the mixture was pumped into an equalization tank. The polymetallic sulfur slag was washed multiple times in the equalization tank until the pH of the washing liquid was neutral. The underflow was then pumped to a belt filter for vacuum filtration to reduce the water content of the filter residue (polymetallic sulfur slag) to 8%.

[0077] The dehydrated filter residue (polymetallic sulfur slag) is directly fed into the coarse sulfur hydrocyclone via a belt conveyor. The temperature in the hydrocyclone is 150℃. Molten sulfur is continuously pumped into the hydrocyclone to melt the newly fed dehydrated filter residue. After holding at this temperature for 60 minutes, the molten sulfur (molten polymetallic sulfur slag) is discharged from the bottom of the coarse sulfur hydrocyclone into a coarse sulfur pool with stirring.

[0078] 2. Molten sulfur (molten polymetallic sulfur slag) was directly fed into a coarse sulfur tank with stirring, and its viscosity was measured to be 2198 mPa·s.

[0079] After holding the mixture at a stirring speed of 200 rpm and a temperature of 150 °C for 20 min, 0.010 mol / kg of sulfur viscosity control agent (viscosity regulator) was added to the molten sulfur (molten polymetallic sulfur slag); then, the mixture was held at a stirring speed of 200 rpm and a temperature of 145 °C for 30 min to obtain the molten sulfur slag (molten slag to be separated) after viscosity reduction control, and its viscosity was measured to be 866 mPa·s.

[0080] The sulfur viscosity control reagent, by mass fraction, consists of: 85% 2-mercaptobenzothiazole, 13% dibenzothiazole disulfide, and 2% diphenylguanidine.

[0081] 3. The molten sulfur slag (molten slag to be separated) after viscosity reduction and adjustment is pumped into a hot filter (150℃ temperature) for filtration (pressure 0.6MPa, filter diameter 0.45μm) to obtain metal filter residue and high-purity sulfur liquid.

[0082] 4. Add 32wt% of a polymer sulfur regulator (polymer sulfur regulator) to the high-purity sulfur solution, and then keep it at a stirring speed of 250rpm and a temperature of 165℃ for 30min to obtain the regulated polymer sulfur solution (molten polymer sulfur solution).

[0083] The polymer sulfur regulator, by mass fraction, consists of: 5% 2-mercaptobenzothiazole, 10% thiazole and 60% benzothiazole, 24% tetramethylthiuram disulfide, 0.9% diphenylguanidine, and 0.1% N,N-dimethyl-2-benzothiazole sulfenamide.

[0084] 5. Add 0.1wt% of polysulfide end-capping agent to the molten polysulfide liquid after heat preservation, keep it at a stirring speed of 200rpm and a temperature of 155℃ for 5min, and then pour it into a -10℃ ice-water mixture to obtain block polysulfide, which is further granulated to obtain polysulfide product.

[0085] The polymeric sulfur end-capping agent, by mass fraction, consists of: 10% lauric acid, 30% oleic acid, and 60% iodine.

[0086] In this embodiment, the Raman correspondence of the polymerized sulfur product is... Figure 3 The sulfur obtained after processing using this technology has a purity of 99.53%, a sulfur recovery rate of 70% from the polymetallic sulfur slag via thermal filtration, and a yield of 35% for the synthesis of polymeric sulfur. Figure 3 As shown, the synthesized product is insoluble in carbon disulfide and has a relatively obvious Raman peak of polymerized sulfur; the heavy metals in the metal filter residue can be further recovered.

[0087] Example 2

[0088] A method for enhancing the filtration and separation of sulfur from metallic sulfur slag includes the following steps:

[0089] Using polymetallic sulfur slag (No. 2 polymetallic sulfur slag) as raw material, its main components are: S 77wt%, Zn 4wt%, Fe 8wt%, Pb 1.44wt%, and others 9.56wt%.

[0090] Dilute sulfuric acid was added to the polymetallic sulfur slag at a liquid-to-solid volume ratio of 4L:1kg, the pH was adjusted to 1.5, and the temperature was raised to 50℃. After stirring for 40 minutes to remove most of the soluble metal sulfates and other substances, the mixture was pumped into an equalization tank. The polymetallic sulfur slag was washed multiple times in the equalization tank until the pH of the washing liquid was neutral. The underflow was then pumped to a belt filter for vacuum filtration, so that the water content of the filter residue (polymetallic sulfur slag) was 9%.

[0091] The dehydrated filter residue (polymetallic sulfur slag) is directly fed into the coarse sulfur hydrocyclone via a belt conveyor. The temperature in the hydrocyclone is 155℃. Molten sulfur is continuously pumped into the hydrocyclone to melt the newly fed dehydrated filter residue. After holding at this temperature for 60 minutes, the molten sulfur (molten polymetallic sulfur slag) is discharged from the bottom of the coarse sulfur hydrocyclone into a coarse sulfur pool with stirring.

[0092] 2. Molten sulfur (molten polymetallic sulfur slag) was directly fed into a coarse sulfur tank with stirring, and its viscosity was measured to be 2354 mPa·s.

[0093] After holding the mixture at a stirring speed of 200 rpm and a temperature of 150 °C for 30 min, 0.015 mol / kg of sulfur viscosity control agent (viscosity control agent) was added to the molten sulfur (molten polymetallic sulfur slag). Then, the mixture was held at a stirring speed of 200 rpm and a temperature of 150 °C for 50 min to obtain the molten sulfur slag (molten slag to be separated) after viscosity reduction control. Its viscosity was measured to be 912 mPa·s.

[0094] The sulfur viscosity control reagent, by mass fraction, consists of: 68% 2-amino-4-methylbenzothiazole, 30% dibenzothiazole disulfide, and 2% diphenylguanidine.

[0095] 3. The molten sulfur slag (molten slag to be separated) after viscosity reduction and adjustment is pumped into a hot filter (150℃) for filtration (pressure 0.6MPa, filter diameter 0.45μm) to obtain metal filter residue and high-purity sulfur liquid.

[0096] 4. Add 38wt% of a polymer sulfur regulator (polymer sulfur regulator) to the high-purity sulfur solution, and then keep it at a stirring speed of 250rpm and a temperature of 155℃ for 40min to obtain the regulated polymer sulfur solution (molten polymer sulfur solution).

[0097] The composition of the polysulfide regulator by mass fraction is: 5% thiazole and 65% benzothiazole, 28% tetramethylthiuram monosulfide, 1.9% diphenylguanidine, and 0.1% N,N-dimethyl-2-benzothiazole sulfenamide.

[0098] 5. Add 0.05wt% of polysulfide end-capping agent to the molten polysulfide liquid after heat preservation, keep it at a stirring speed of 200rpm and a temperature of 160℃ for 5min, and then pour it into a -15℃ ice-water mixture to obtain block polysulfide, which is further granulated to obtain polysulfide product.

[0099] The polymeric sulfur end-capping agent, by mass fraction, consists of: 10% lauric acid, 20% oleic acid, and 70% iodine.

[0100] In this embodiment, the sulfur purity in the sulfur product is 99.41%, the sulfur thermal filtration recovery rate in the polymetallic sulfur slag is 69%, the yield of synthetic polymerized sulfur is 38%, and the heavy metals in the metal filter residue can be further recovered.

[0101] Example 3

[0102] Compared to Example 1, all other operations are exactly the same as in Example 1, except for the difference in the formulation of the polymer sulfur regulator.

[0103] Polymer sulfur regulator: 10% thiazole and 65% benzothiazole, 24% tetramethylthiuram disulfide, 0.9% diphenylguanidine, and 0.1% N,N-dimethyl-2-benzothiazole sulfenamide.

[0104] The final yield of polymerized sulfur was 33%.

[0105] Example 4

[0106] Compared to Example 1, all other operations are exactly the same as in Example 1, except for the difference in the formulation of the polymer sulfur regulator.

[0107] Polymer sulfur regulator: 10% 2-mercaptobenzothiazole and 65% benzothiazole, 24% tetramethylthiuram disulfide, 0.9% diphenylguanidine, and 0.1% N,N-dimethyl-2-benzothiazole sulfenamide.

[0108] The final yield of polymerized sulfur was 31%.

[0109] Example 5 (Control Example)

[0110] Compared to Example 1, all other operations are exactly the same as in Example 1, except for the difference in the formulation of the polymer sulfur regulator.

[0111] 2-Mercaptobenzothiazole 25% and thiazole 50%, tetramethylthiuram disulfide 24%, diphenylguanidine 0.9%, N,N-dimethyl-2-benzothiazole sulfenamide 0.1%.

[0112] The final yield of polymerized sulfur was 24%.

[0113] Example 6 (Control Example)

[0114] Compared to Example 1, all other operations are exactly the same as in Example 1, except for the difference in the formulation of the polymer sulfur regulator.

[0115] 2-Mercaptobenzothiazole 6%, thiazole 13% and benzothiazole 80%, diphenylguanidine 0.9%, N,N-dimethyl-2-benzothiazole sulfenamide 0.1%.

[0116] The final yield of polymerized sulfur was 29%.

[0117] Example 7 (Control Example)

[0118] Compared to Example 1, all other operations are exactly the same as in Example 1, except for the difference in the formulation of the polymer sulfur regulator.

[0119] 2-Mercaptobenzothiazole 5%, thiazole 10% and benzothiazole 60%, tetramethylthiuram disulfide 24%, N,N-dimethyl-2-benzothiazole sulfenamide 1%.

[0120] The final yield of polymerized sulfur was 31%.

[0121] Example 8 (Control Example)

[0122] Compared to Example 1, all other operations are exactly the same as in Example 1, except for the difference in the formulation of the polymer sulfur regulator.

[0123] 2-Mercaptobenzothiazole 5%, thiazole 10% and benzothiazole 60%, tetramethylthiuram disulfide 24%, diphenylguanidine 1%.

[0124] The final yield of polymerized sulfur was 31%.

[0125] Example 9 (Control Example)

[0126] Compared to Example 1, all other operations are exactly the same as in Example 1, except for the amount of polymeric sulfur regulator used.

[0127] Add 15 wt% of polymeric sulfur control reagent to the high-purity sulfur solution.

[0128] The final yield of polymerized sulfur was 17%.

[0129] The above technical solutions of the present invention are merely preferred embodiments of the present invention and do not limit the patent scope of the present invention. All equivalent structural transformations made under the technical concept of the present invention using the contents of the present invention specification and drawings, or direct / indirect applications in other related technical fields, are included in the patent protection scope of the present invention.

Claims

1. A method for enhancing the filtration and separation of sulfur from metallic sulfur slag and preparing polymeric sulfur, characterized in that: Metal sulfur slag is subjected to acid leaching, water washing, dehydration and melt pretreatment to obtain molten metal sulfur slag. A viscosity modifier is added to the molten metal sulfur slag and stirred to react. After pressure filtration, sulfur liquid is obtained. A polymerization modifier is added to the sulfur liquid to polymerize, and then a polymer sulfur end-capping agent is added to end-cap, to obtain polymer sulfur liquid. The polymer sulfur liquid is added to ice water to cool, to obtain polymer sulfur product. The viscosity modifier includes thiazoles and guanidines; The polymeric sulfur regulators include thiazoles, thiurams, sulfenamides, and guanidines.

2. The method for enhancing the filtration and separation of sulfur from metallic sulfur slag and preparing polymeric sulfur according to claim 1, characterized in that: The viscosity modifier comprises the following components by mass percentage: 80-98% thiazoles and 2-20% guanidines; the thiazole is at least one of 2-mercaptobenzothiazole, 2-amino-4-methylbenzothiazole, and dibenzothiazole disulfide; the guanidine is diphenylguanidine.

3. A method for filtering and separating sulfur from enhanced metallic sulfur slag and preparing polymeric sulfur according to claim 1 or 2, characterized in that: The amount of the viscosity modifier is 0.005 to 0.020 mol / kg of the metal sulfur slag.

4. A method for filtering and separating sulfur from enhanced metallic sulfur slag and preparing polymeric sulfur according to claim 1 or 2, characterized in that: The conditions for the stirring reaction are: stirring at 140–150°C for 20–200 min.

5. The method for filtering and separating sulfur from enhanced metallic sulfur slag and preparing polymeric sulfur according to claim 1, characterized in that: The polymerization regulator comprises the following components by mass percentage: 59-75% thiazoles, 24-40% thiurams, 0.05-3% sulfenamides, and 0.05-3% guanidines; wherein the thiazoles are benzothiazoles or a combination of benzothiazoles with thiazoles and / or 2-mercaptobenzothiazoles; the thiurams are at least one of tetramethylthiuram disulfide, tetramethylthiuram monosulfide, and bis(pentamethylenethiuram) tetrasulfide; the guanidines are diphenylguanidines; and the sulfenamides are N,N-dimethyl-2-benzothiazole sulfenamides.

6. A method for filtering and separating sulfur from enhanced metallic sulfur slag and preparing polymeric sulfur according to claim 1 or 5, characterized in that: The mass of the polymerization regulator is 20-50% of the mass of the metal sulfur slag.

7. A method for filtering and separating sulfur from enhanced metallic sulfur slag and preparing polymeric sulfur according to claim 1 or 5, characterized in that: The polymerization conditions are: temperature 145–165°C, time 20–60 min.

8. The method for filtering and separating sulfur from enhanced metallic sulfur slag and preparing polymeric sulfur according to claim 1, characterized in that: The polymeric sulfur end-capping agent comprises the following components by weight percentage: lauric acid 5-30%, oleic acid 10-50%, and iodine 20-80%.

9. A method for filtering and separating sulfur from enhanced metallic sulfur slag and preparing polymeric sulfur according to claim 1 or 8, characterized in that: The amount of the polymeric sulfur end-capping agent is 0.1-2% of the mass of the metallic sulfur slag.

10. A method for filtering and separating sulfur from enhanced metallic sulfur slag and preparing polymeric sulfur according to claim 1 or 8, characterized in that: The end-capping conditions are: reaction at 145–165°C for 5–30 min.

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