A method for reducing sulfur production in tail gas from acid decomposition of titanium concentrate

Abstract

The present invention relates to a method for reducing the amount of sulfur generated in the tail gas from the acid hydrolysis of titanium concentrate. The method comprises the following steps: mixing the titanium concentrate with concentrated sulfuric acid, then adding water to initiate a reaction, and heating to perform a primary acid hydrolysis reaction, thereby producing an acid ore slurry; subjecting the acid ore slurry to a secondary acid hydrolysis reaction in an aerobic environment, thereby oxidizing the pyrrhotite in the titanium concentrate under acidic conditions into an intermediate product that adheres to the pyrrhotite surface, reducing the formation of elemental sulfur, and producing a slaking material; and leaching the slaking material to extract an acid hydrolysis titanium solution. This method solves the problem of sublimated sulfur generated in the existing titanium dioxide production process from titanium concentrate, which tends to remain in production pipelines, thereby clogging the pipelines and affecting the continuity and economic efficiency of production.

Description

Technical Field

[0001] The invention relates to the technical field of titanium dioxide production, and in particular to a method for reducing sulfur generation in tail gas from acid decomposition of titanium concentrate. Background Art

[0002] The sulfuric acid method and the chloride method are currently the two mainstream methods for producing titanium dioxide products. Due to its strong adaptability to raw ore and relatively mature production processes and procedures, the sulfuric acid method currently occupies a dominant position in my country's titanium dioxide production process. Among the series of production processes for preparing titanium dioxide using the sulfuric acid method, acid hydrolysis of titanium concentrate is a key step in ensuring the quality and output of subsequent products. However, this process produces tail gas containing various sulfides. In the actual industrial production of titanium dioxide using the sulfuric acid method, it has been found that these sulfur-containing gases not only pollute the natural environment, but the sublimated sulfur in the tail gas easily condenses into solid sulfur when it is cooled and adheres to the system, causing blockage of the pipeline exhaust system equipment, requiring frequent manual cleaning, and preventing the acid hydrolysis system from operating continuously and stably, seriously affecting the normal production and production efficiency of the acid hydrolysis process.

[0003] Therefore, developing a new technology and process that can reduce the amount of sublimated sulfur generated in titanium concentrate tail gas is of great practical significance for promoting clean production in my country's sulfuric acid process titanium dioxide production industry.

[0004] Current research on titanium concentrate acid hydrolysis tail gas mainly focuses on the following two aspects:

[0005] (1) Confirmation of exhaust gas composition. The sulfuric acid method titanium dioxide acid hydrolysis reaction has the characteristics of short main reaction time and instantaneous exhaust gas emission. The main components of the exhaust gas produced by acid hydrolysis are SO2, H2S, SO3, S and acid mist.

[0006] (2) Treatment measures for sulfur-containing tail gas. Currently, the main treatment processes for tail gas generated by sulfuric acid hydrolysis of titanium concentrate include Venturi spraying, low-temperature Claus process, hydrogenation reduction absorption, and electrostatic demisting, but these methods all have certain limitations. The above process methods are all aimed at the sulfur-containing gas in the tail gas, and there are few reports on the treatment of sublimated sulfur.

[0007] In actual industrial production, sublimated sulfur in tail gas cools and condenses in a solid form as the temperature drops. This solid is retained within the production pipeline, clogging the pipeline and impacting the continuity and economic viability of sulfuric acid titanium dioxide production. With the continuous development of my country's titanium dioxide industry and the widespread application of sulfuric acid titanium dioxide, the generation of sublimated sulfur in acid hydrolysis tail gas has seriously impacted the continuous and clean production of sulfuric acid titanium dioxide. Therefore, analyzing the sources of sublimated sulfur in acid hydrolysis tail gas, exploring the various production factors that influence its generation, and identifying a method to control and reduce its generation at the source are of great economic and social significance for resolving the series of production issues caused by sublimated sulfur and promoting the "green chemical" production of sulfuric acid titanium dioxide. Summary of the Invention

[0008] The purpose of the present invention is to provide a method for reducing the amount of sulfur generated in the tail gas of acid hydrolysis of titanium concentrate, so as to solve the problem that the sublimated sulfur generated in the existing process of producing titanium dioxide from titanium concentrate is easily retained in the production pipeline, thereby blocking the pipeline and affecting the continuity and economy of production.

[0009] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0010] A method for reducing sulfur production in tail gas from acid hydrolysis of titanium concentrate comprises the following steps:

[0011] S1. Mixing titanium concentrate and concentrated sulfuric acid, then adding water to initiate a reaction, and heating to perform an acid hydrolysis reaction to obtain an acid ore slurry;

[0012] S2. Under an aerobic environment, the acid ore slurry is subjected to a secondary acid hydrolysis reaction, i.e., heat preservation and aging, so that the pyrrhotite in the titanium concentrate is oxidized into an intermediate product under acidic conditions and adheres to the surface of the pyrrhotite, thereby reducing the generation of elemental sulfur and obtaining a slaked material;

[0013] S3, leaching the slaked material to extract the acid-hydrolyzed titanium solution.

[0014] According to the above technical means, by creating an aerobic environment during the secondary acid hydrolysis (insulation and aging) stage after the primary acid hydrolysis of the titanium concentrate, the pyrrhotite in the titanium concentrate is oxidized under acidic conditions to the intermediate product Fe(OH)3 and attached to the surface of the pyrrhotite, effectively reducing the probability of the pyrrhotite reacting with concentrated sulfuric acid to produce elemental sulfur. At the same time, due to the presence of an aerobic environment, the newly generated elemental sulfur in the reaction material can continue to be deeply oxidized to produce gaseous sulfur oxides. The two mechanisms work together to greatly reduce the generation of sublimated sulfur, thereby greatly reducing the sublimated sulfur remaining in the production pipeline, thereby ensuring the continuity and economy of production. This solves the problem that the sublimated sulfur generated in the existing titanium dioxide production process from titanium concentrate is easily retained in the production pipeline, thereby clogging the pipeline and affecting the continuity and economy of production.

[0015] Among them, acidolysis is an important step to ensure the quality and output of titanium dioxide production, and is the most important link in the industrial production of titanium dioxide. The present invention only introduces an aerobic environment in the secondary acidolysis (insulation and maturation) stage of the titanium concentrate acidolysis slurry, and will not cause a decrease in the acidolysis rate of the titanium concentrate in the process of reducing the amount of sublimated sulfur generated, thereby effectively ensuring the quality and output of titanium dioxide production.

[0016] Preferably, in S1, the mass ratio of titanium concentrate to concentrated sulfuric acid is 1.5 to 1.56.

[0017] Preferably, in S1, the maximum temperature of the acid hydrolysis reaction is 185°C to 190°C. When the reaction reaches this temperature range, heating is immediately stopped. Since the temperature rises quickly when heating in an electric furnace, the maximum temperature is within a temperature range.

[0018] Preferably, S2 includes: subjecting the acid ore slurry to a secondary acidolysis reaction under the condition of introducing air, i.e., thermal aging, so that the pyrrhotite in the titanium concentrate is oxidized into an intermediate product under acidic conditions and adheres to the surface of the pyrrhotite, thereby reducing the generation of elemental sulfur and obtaining a slaked material.

[0019] Preferably, the air introduction rate is 20 to 80 mL / min.

[0020] By controlling the air flow rate between 20 and 80 mL / min, pyrrhotite can be effectively oxidized into intermediate products, while avoiding the problem of excessive flow rate causing the reaction materials to be blown onto the reactor wall, resulting in a reduced amount of pyrrhotite oxidized.

[0021] In actual experiments, it was found that when the air intake was greater than 80 mL / min, the reaction materials would be blown onto the reactor wall or splashed out, which not only made it impossible to accurately calculate the amount of oxidized pyrrhotite, but also made it impossible for the reactor wall or splashed pyrrhotite to be effectively oxidized, thereby reducing the amount of oxidized pyrrhotite.

[0022] Preferably, the temperature of the secondary acid hydrolysis reaction, i.e., the heat preservation and aging, is 150°C to 170°C.

[0023] By controlling the temperature of the secondary acidolysis reaction, i.e., thermal aging, between 150°C and 170°C, the acid ore slurry is matured while the pyrrhotite in the titanium concentrate is oxidized into intermediate products under acidic conditions and attached to the surface of the pyrrhotite, thereby reducing the generation of elemental sulfur.

[0024] Preferably, the secondary acid hydrolysis reaction, i.e., the heat preservation and aging time is 110 min to 130 min.

[0025] Preferably, the secondary acid hydrolysis reaction, i.e., the heat preservation and aging time is 120 minutes.

[0026] Preferably, in S1, the concentration of sulfuric acid in the concentrated sulfuric acid is 82% to 90%.

[0027] Preferably, in S1, the water is deionized water, and the amount of deionized water added is calculated based on the concentration of sulfuric acid in the mixed solution after the addition of water.

[0028] Preferably, in S1, the titanium concentrate is titanium concentrate powder, and the particle size of the titanium concentrate powder is between 0.27 and 27 μm.

[0029] Preferably, in S3, the leaching temperature is 60° C. to 70° C., the leaching time is 110 min to 130 min, and the leaching stirring rate is 200 r / min to 300 r / min.

[0030] Preferably, in S3, the leaching temperature is 65° C., the leaching time is 120 min, and the stirring rate of the leaching is 250 r / min. The beneficial effects of the present invention are:

[0031] Compared with the traditional acid decomposition method, the method of reducing the amount of sulfur generated in the tail gas of the acid decomposition of titanium concentrate of the present invention creates an aerobic environment in the secondary acid decomposition (heat preservation and aging) stage after the primary acid decomposition of the titanium concentrate, and reasonably controls the temperature of the secondary acid decomposition (heat preservation and aging), so that the pyrrhotite in the titanium concentrate is oxidized to the intermediate product Fe(OH)3 under acidic conditions and adheres to the surface of the pyrrhotite, thereby effectively reducing the probability of the pyrrhotite reacting with concentrated sulfuric acid to generate elemental sulfur; at the same time, due to the presence of the aerobic environment, the newly generated elemental sulfur in the reaction material can continue to be deeply oxidized, generating into gaseous sulfur oxides; the two mechanisms work together to greatly reduce the generation of sublimated sulfur, thereby greatly reducing the sublimated sulfur remaining in the production pipeline, thereby ensuring the continuity and economy of production. Experimental studies have shown that by introducing an aerobic environment in the secondary acid decomposition (insulation and aging) stage, the acid decomposition rate of the titanium concentrate will not be reduced in the process of reducing the generation of sublimated sulfur, so that the acid decomposition rate of the titanium concentrate can still be maintained at a high level. The method of the present invention has the advantages of simple operation, low cost and high efficiency, and has promotion and application value in the field of titanium dioxide production technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a flow chart of the method for reducing the amount of sulfur generated in the tail gas from the acidolysis of titanium concentrate according to the present invention;

[0033] Figure 2 This is a graph showing the changing trend of the sublimated sulfur mass reduction rate and air flow rate;

[0034] Figure 3 This is a trend chart of the acid decomposition rate and air flow rate. DETAILED DESCRIPTION

[0035] The following describes the embodiments of the present invention with reference to the accompanying drawings and preferred embodiments. Those skilled in the art will readily appreciate the other advantages and benefits of the present invention from the disclosure herein. The present invention may also be implemented or applied through various other specific embodiments, and the various details in this specification may be modified or altered based on different viewpoints and applications without departing from the spirit of the present invention. It should be understood that the preferred embodiments are intended only to illustrate the present invention and are not intended to limit the scope of protection of the present invention.

[0036] Example 1

[0037] like Figure 1 As shown, a method for reducing the amount of sulfur generated in the tail gas of acid decomposition of titanium concentrate comprises the following steps:

[0038] S1: titanium concentrate and concentrated sulfuric acid are mixed, and then water is added to initiate the reaction. The mixture is heated in an electric furnace to perform an acid hydrolysis reaction to obtain an acid ore slurry, which specifically includes:

[0039] 9166 g of titanium concentrate was ball-milled for 100 minutes and 7930 ml of 98% concentrated sulfuric acid were added to a reactor, and then the two were stirred and mixed at a speed of 100 rpm for 1 minute. Subsequently, 2231 ml of deionized water was added to the reactor to initiate the reaction. The reactor was heated in an electric furnace to perform an acid hydrolysis reaction, so that the titanium concentrate reacted with the concentrated sulfuric acid (the maximum reaction temperature was controlled in the temperature range of 185-190° C.), to obtain an acid ore slurry;

[0040] S2. Under an aerobic environment, the acid ore slurry is subjected to a secondary acid hydrolysis reaction, i.e., heat preservation and aging, so that the pyrrhotite in the titanium concentrate is oxidized into an intermediate product under acidic conditions and adheres to the surface of the pyrrhotite, thereby reducing the generation of elemental sulfur and obtaining a slaking material, which specifically includes:

[0041] Air is introduced into the acid ore slurry in the reactor at an air flow rate of 20 ml / min, and the acid ore slurry is subjected to a secondary acid hydrolysis reaction, i.e., heat preservation and aging, so that the pyrrhotite in the titanium concentrate is oxidized into an intermediate product under acidic conditions and adheres to the surface of the pyrrhotite, thereby reducing the generation of elemental sulfur and obtaining a slaked material. When the temperature reaches 180° C., the timing is started, and the sublimated sulfur generated by the reaction is collected by a condensing device above the reactor. After the reaction lasts for 30 minutes, the heating is stopped, and the condensed sublimated sulfur attached to the condensing device and the reactor is washed and collected with a KOH-C2H5OH solution;

[0042] S3, leaching the slaking material to extract the acid-hydrolyzed titanium solution, specifically comprising:

[0043] The slaked material is stirred and immersed in water, and the solid and liquid are separated to obtain an acid hydrolysis titanium liquid; wherein, the leaching temperature is 65°C, the leaching time is 120 minutes, and the leaching stirring rate is 250 r / min. After the stirring is completed, the leaching liquid is separated into solid and liquid to obtain a supernatant and an acid hydrolysis slag, and then the titanium content in the liquid phase and the solid phase are respectively measured to obtain the acid hydrolysis rate of the titanium concentrate.

[0044] Example 2

[0045] like Figure 1 As shown, a method for reducing the amount of sulfur generated in the tail gas of acid decomposition of titanium concentrate comprises the following steps:

[0046] S1, titanium concentrate and concentrated sulfuric acid are mixed, then water is added to initiate the reaction, and the mixture is heated in an electric furnace to undergo an acid hydrolysis reaction.

[0047] Obtaining acid ore slurry, specifically comprising:

[0048] 9166 g of titanium concentrate was ball-milled for 100 minutes and 7930 ml of 98% concentrated sulfuric acid were added to a reactor, and then the two were stirred and mixed at a speed of 100 rpm for 1 minute. Subsequently, 2231 ml of deionized water was added to the reactor to initiate the reaction. The reactor was heated in an electric furnace to perform an acid hydrolysis reaction, so that the titanium concentrate reacted with the concentrated sulfuric acid (the maximum reaction temperature was controlled in the temperature range of 185-190° C.), to obtain an acid ore slurry;

[0049] S2. Under an aerobic environment, the acid ore slurry is subjected to a secondary acid hydrolysis reaction, i.e., heat preservation and aging, so that the pyrrhotite in the titanium concentrate is oxidized into an intermediate product under acidic conditions and adheres to the surface of the pyrrhotite, thereby reducing the generation of elemental sulfur and obtaining a slaking material, which specifically includes:

[0050] Air is introduced into the acid ore slurry in the reactor at an air flow rate of 40 ml / min, and the acid ore slurry is subjected to a secondary acid hydrolysis reaction, i.e., heat preservation and aging, so that the pyrrhotite in the titanium concentrate is oxidized into an intermediate product under acidic conditions and adheres to the surface of the pyrrhotite, thereby reducing the generation of elemental sulfur and obtaining a slaked material. When the temperature reaches 180° C., the timing is started, and the sublimated sulfur generated by the reaction is collected by a condensing device above the reactor. After the reaction lasts for 30 minutes, the heating is stopped, and the condensed sublimated sulfur attached to the condensing device and the reactor is washed and collected with a KOH-C2H5OH solution;

[0051] S3, leaching the slaking material to extract the acid-hydrolyzed titanium solution, specifically comprising:

[0052] The slaked material is stirred and immersed in water, and the solid and liquid are separated to obtain an acid hydrolysis titanium liquid; wherein, the leaching temperature is 65°C, the leaching time is 120 minutes, and the leaching stirring rate is 250r / min. After the stirring is completed, the leaching liquid is separated into solid and liquid to obtain a supernatant and an acid hydrolysis slag, and then the titanium content in the liquid phase and the solid phase are respectively measured to obtain the acid hydrolysis rate of the titanium concentrate.

[0053] Example 3

[0054] like Figure 1 As shown, a method for reducing the amount of sulfur generated in the tail gas of acid decomposition of titanium concentrate comprises the following steps:

[0055] S1: titanium concentrate and concentrated sulfuric acid are mixed, and then water is added to initiate the reaction. The mixture is heated in an electric furnace to perform an acid hydrolysis reaction to obtain an acid ore slurry, which specifically includes:

[0056] 9166 g of titanium concentrate was ball-milled for 100 minutes and 7930 ml of 98% concentrated sulfuric acid were added to a reactor, and then the two were stirred and mixed at a speed of 100 rpm for 1 minute. Subsequently, 2231 ml of deionized water was added to the reactor to initiate the reaction. The reactor was heated in an electric furnace to perform an acid hydrolysis reaction, so that the titanium concentrate reacted with the concentrated sulfuric acid (the maximum reaction temperature was controlled in the temperature range of 185-190° C.), to obtain an acid ore slurry;

[0057] S2. Under an aerobic environment, the acid ore slurry is subjected to a secondary acid hydrolysis reaction, i.e., heat preservation and aging, so that the pyrrhotite in the titanium concentrate is oxidized into an intermediate product under acidic conditions and adheres to the surface of the pyrrhotite, thereby reducing the generation of elemental sulfur and obtaining a slaking material, which specifically includes:

[0058] Air is introduced into the acid ore slurry in the reactor at an air flow rate of 60 ml / min, and the acid ore slurry is subjected to a secondary acid hydrolysis reaction, i.e., heat preservation and aging, so that the pyrrhotite in the titanium concentrate is oxidized into an intermediate product under acidic conditions and adheres to the surface of the pyrrhotite, thereby reducing the generation of elemental sulfur and obtaining a slaked material. When the temperature reaches 180° C., the timing is started, and the sublimated sulfur generated by the reaction is collected by a condensing device above the reactor. After the reaction lasts for 30 minutes, the heating is stopped, and the condensed sublimated sulfur attached to the condensing device and the reactor is washed and collected with a KOH-C2H5OH solution;

[0059] S3, leaching the slaking material to extract the acid-hydrolyzed titanium solution, specifically comprising:

[0060] The slaked material is stirred and immersed in water, and the solid and liquid are separated to obtain an acid hydrolysis titanium liquid; wherein, the leaching temperature is 65°C, the leaching time is 120 minutes, and the leaching stirring rate is 250r / min. After the stirring is completed, the leaching liquid is separated into solid and liquid to obtain a supernatant and an acid hydrolysis slag, and then the titanium content in the liquid phase and the solid phase are respectively measured to obtain the acid hydrolysis rate of the titanium concentrate.

[0061] Example 4

[0062] like Figure 1 As shown, a method for reducing the amount of sulfur generated in the tail gas of acid decomposition of titanium concentrate comprises the following steps:

[0063] S1: titanium concentrate and concentrated sulfuric acid are mixed, and then water is added to initiate the reaction. The mixture is heated in an electric furnace to perform an acid hydrolysis reaction to obtain an acid ore slurry, which specifically includes:

[0064] 9166 g of titanium concentrate was ball-milled for 100 minutes and 7930 ml of 98% concentrated sulfuric acid were added to a reactor, and then the two were stirred and mixed at a speed of 100 rpm for 1 minute. Subsequently, 2231 ml of deionized water was added to the reactor to initiate the reaction. The reactor was heated in an electric furnace to perform an acid hydrolysis reaction, so that the titanium concentrate reacted with the concentrated sulfuric acid (the maximum reaction temperature was controlled in the temperature range of 185-190° C.), to obtain an acid ore slurry;

[0065] S2. Under an aerobic environment, the acid ore slurry is subjected to a secondary acid hydrolysis reaction, i.e., heat preservation and aging, so that the pyrrhotite in the titanium concentrate is oxidized into an intermediate product under acidic conditions and adheres to the surface of the pyrrhotite, thereby reducing the generation of elemental sulfur and obtaining a slaking material, which specifically includes:

[0066] Air is introduced into the acid ore slurry in the reactor at an air flow rate of 80 ml / min, and the acid ore slurry is subjected to a secondary acid hydrolysis reaction, i.e., heat preservation and aging, so that the pyrrhotite in the titanium concentrate is oxidized into an intermediate product under acidic conditions and adheres to the surface of the pyrrhotite, thereby reducing the generation of elemental sulfur and obtaining a slaked material. When the temperature reaches 180° C., the timing is started, and the sublimated sulfur generated by the reaction is collected by a condensing device above the reactor. After the reaction lasts for 30 minutes, the heating is stopped, and the condensed sublimated sulfur attached to the condensing device and the reactor is washed and collected with a KOH-C2H5OH solution;

[0067] S3, leaching the slaking material to extract the acid-hydrolyzed titanium solution, specifically comprising:

[0068] The slaked material is stirred and immersed in water, and the solid and liquid are separated to obtain an acid hydrolysis titanium liquid; wherein, the leaching temperature is 65°C, the leaching time is 120 minutes, and the leaching stirring rate is 250r / min. After the stirring is completed, the leaching liquid is separated into solid and liquid to obtain a supernatant and an acid hydrolysis slag, and then the titanium content in the liquid phase and the solid phase are respectively measured to obtain the acid hydrolysis rate of the titanium concentrate.

[0069] Comparative Example 1

[0070] A conventional method for acid hydrolysis of titanium concentrate comprises the following steps:

[0071] like Figure 1As shown, a method for reducing the amount of sulfur generated in the tail gas of acid decomposition of titanium concentrate comprises the following steps:

[0072] S1: titanium concentrate and concentrated sulfuric acid are mixed, and then water is added to initiate the reaction. The mixture is heated in an electric furnace to perform an acid hydrolysis reaction to obtain an acid ore slurry, which specifically includes:

[0073] 9166 g of titanium concentrate was ball-milled for 100 minutes and 7930 ml of 98% concentrated sulfuric acid were added to a reactor, and then the two were stirred and mixed at a speed of 100 rpm for 1 minute. Subsequently, 2231 ml of deionized water was added to the reactor to initiate the reaction. The reactor was heated in an electric furnace to perform an acid hydrolysis reaction, so that the titanium concentrate reacted with the concentrated sulfuric acid (the maximum reaction temperature was controlled in the temperature range of 185-190° C.), to obtain an acid ore slurry;

[0074] S2,

[0075] No air is introduced into the acid ore slurry in the reactor, so that the secondary acid hydrolysis reaction is carried out naturally to obtain the slaking material. When the temperature reaches 180°C, the timing is started, and the sublimated sulfur produced by the reaction is collected through the condensation device above the reactor. After the reaction lasts for 30 minutes, the heating is stopped, and the condensed sublimated sulfur attached to the condensation device and the reactor is washed and collected with a KOH-C2H5OH solution.

[0076] S3, leaching the slaking material to extract the acid-hydrolyzed titanium solution, specifically comprising:

[0077] The slaked material is stirred and immersed in water, and the solid and liquid are separated to obtain an acid hydrolysis titanium liquid; wherein, the leaching temperature is 65°C, the leaching time is 120 minutes, and the leaching stirring rate is 250 r / min. After the stirring is completed, the leaching liquid is separated into solid and liquid to obtain a supernatant and an acid hydrolysis slag, and then the titanium content in the liquid phase and the solid phase are respectively measured to obtain the acid hydrolysis rate of the titanium concentrate.

[0078] Detection and Analysis

[0079] 1) The sulfur content of the KOH-C2H5OH solution after collecting sublimed sulfur in Examples 1 to 4 and Comparative Example 1 was measured by ultraviolet spectrophotometry. The results are as follows:

[0080] The sulfur content in the KOH-C2H5OH solution after collecting sublimed sulfur in Example 1 was reduced by 17.53% compared with the sulfur content in the KOH-C2H5OH solution after collecting sublimed sulfur in Control Example 1; the sulfur content in the KOH-C2H5OH solution after collecting sublimed sulfur in Example 2 was reduced by 29.14% compared with the sulfur content in the KOH-C2H5OH solution after collecting sublimed sulfur in Control Example 1; the sulfur content in the KOH-C2H5OH solution after collecting sublimed sulfur in Example 3 was reduced by 29.00% compared with the sulfur content in the KOH-C2H5OH solution after collecting sublimed sulfur in Control Example 1; the sulfur content in the KOH-C2H5OH solution after collecting sublimed sulfur in Example 2 was reduced by 35.40% compared with the sulfur content in the KOH-C2H5OH solution after collecting sublimed sulfur in Control Example 1.

[0081] Among them, the changing trends of sublimated sulfur mass reduction rate and air flow rate are as follows: Figure 2 As shown, from Figure 2 From the analysis, it can be seen that the reduction rate of sublimated sulfur mass increases with the increase of air flow rate.

[0082] The acid hydrolysis rates of the titanium concentrates in Examples 1 to 4 and Comparative Example 1 were measured, and the calculation formula for the acid hydrolysis rates was as follows:

[0083]

[0084] in

[0085]

[0086]

[0087] Where:

[0088] A is the standard ammonium ferric sulfate titration number consumed when titrating the titanium content in the titanium solution (ml);

[0089] 0.51 is the titration number of the blank group (ml);

[0090] 0.05 is the molar concentration of ferric ammonium sulfate standard solution (mol / L);

[0091] B is the titration number consumed when titrating the insoluble titanium content in the acid solution residue (ml);

[0092] C is the mass of dry titanium slag weighed when titrating the insoluble titanium content in the acid hydrolysis slag (g);

[0093] X is the mass of the acid-hydrolyzed residue after drying (g).

[0094] Here are the results:

[0095] It was found that when 20, 40, 60 and 80 ml / min of air were respectively introduced into the acid ore slurry during the maturation stage in Examples 1 to 4, the acidolysis rates of the titanium concentrate were 87.06%, 86.94%, 86.92% and 87.01%, respectively. In the control example 1, when no air was introduced during the maturation stage, the acidolysis rate of the titanium concentrate was 87.08%, thereby proving that the introduction of air during the acidolysis and maturation stage of the titanium concentrate will not affect the acidolysis rate of the titanium concentrate.

[0096] Among them, the changing trends of acid decomposition rate and air flow rate are as follows: Figure 3 As shown, from Figure 3 From the analysis, it can be seen that with the increase of air flow rate, the acidolysis rate has no obvious change, which proves that the introduction of air during the maturation stage will not affect the acidolysis rate of titanium concentrate. Acidolysis is an important step to ensure the quality and output of titanium dioxide production. It is the most important link in the industrial production of titanium dioxide, thus effectively ensuring the quality and output of titanium dioxide production.

[0097] In summary, the method of reducing the amount of sulfur generated in the acidolysis tail gas of titanium concentrate of the present invention, compared with the traditional acidolysis method, creates an aerobic environment in the heat preservation and maturation stage after the acidolysis of the titanium concentrate, so that the pyrrhotite in the titanium concentrate is oxidized to the intermediate product Fe(OH)3 under acidic conditions and adheres to the surface of the pyrrhotite, effectively reducing the probability of pyrrhotite reacting with concentrated sulfuric acid to generate elemental sulfur; at the same time, due to the presence of an aerobic environment, the newly generated elemental sulfur in the reaction material can continue to be deeply oxidized to generate gaseous sulfur oxides; the two mechanisms work together to greatly reduce the generation of sublimated sulfur, thereby greatly reducing the sublimated sulfur remaining in the production pipeline, thereby ensuring the continuity and economy of production, and experimental research has proved that by introducing an aerobic environment in the heat preservation and maturation stage, the acidolysis rate of the titanium concentrate will not be reduced in the process of reducing the amount of sublimated sulfur generated, so that the acidolysis rate of the titanium concentrate can still be maintained at a high level, and the method of the present invention has the advantages of simple operation, low cost and high efficiency, and has promotion and application value in the field of titanium dioxide production technology.

[0098] The above embodiments are only preferred embodiments for fully illustrating the present invention, and the protection scope of the present invention is not limited thereto. Any equivalent substitution or modification made by those skilled in the art based on the present invention is within the protection scope of the present invention.

Claims

1. A method for reducing the amount of sulfur generated in the tail gas of acid hydrolysis of titanium concentrate, characterized in that: The following steps are involved: S1. Mixing titanium concentrate and concentrated sulfuric acid, then adding water to initiate a reaction, and heating to perform an acid hydrolysis reaction to obtain an acid ore slurry; S2. Under an aerobic environment, the acid ore slurry is subjected to a secondary acid hydrolysis reaction, so that the pyrrhotite in the titanium concentrate is oxidized into an intermediate product under acidic conditions and adheres to the surface of the pyrrhotite, thereby reducing the generation of elemental sulfur and obtaining a slaking material; S3, leaching the slaked material to extract the acid-hydrolyzed titanium solution.

2. The method for reducing sulfur production in tail gas from acid hydrolysis of titanium concentrate according to claim 1, characterized in that: In S1, the mass ratio of titanium concentrate to concentrated sulfuric acid is 1.5-1.

56.

3. The method for reducing sulfur production in tail gas from acid hydrolysis of titanium concentrate according to claim 1, characterized in that: In S1, the temperature of the primary acid hydrolysis reaction is 185°C to 190°C.

4. The method for reducing sulfur production in tail gas from acid hydrolysis of titanium concentrate according to claim 1, characterized in that: Said S2 comprises: subjecting the acid ore slurry to a secondary acid hydrolysis reaction under the condition of introducing air, so that the pyrrhotite in the titanium concentrate is oxidized into an intermediate product under acidic conditions and adheres to the surface of the pyrrhotite, thereby reducing the generation of elemental sulfur and obtaining a slaking material.

5. The method for reducing sulfur production in tail gas from acid hydrolysis of titanium concentrate according to claim 4, characterized in that: The air flow rate is 20-80 mL / min.

6. The method for reducing sulfur production in tail gas from acid hydrolysis of titanium concentrate according to claim 1, characterized in that: In S2, the temperature of the secondary acid hydrolysis reaction is 150°C to 170°C.

7. The method for reducing sulfur production in tail gas from acid hydrolysis of titanium concentrate according to claim 1, characterized in that: In S2, the secondary acid hydrolysis reaction time is 100 min to 130 min.

8. The method for reducing sulfur production in tail gas from acid hydrolysis of titanium concentrate according to claim 1, characterized in that: In the S1, the concentration of sulfuric acid in the mixed solution after adding water is 82% to 90%.

9. The method for reducing sulfur production in tail gas from acid hydrolysis of titanium concentrate according to claim 1, characterized in that: In S1, the titanium concentrate is titanium concentrate powder, and the particle size of the titanium concentrate powder is between 0.27 and 27 μm.

10. The method for reducing sulfur production in tail gas from acid hydrolysis of titanium concentrate according to claim 1, characterized in that: In the S3, the leaching temperature is 60° C. to 70° C., the leaching time is 110 min to 130 min, and the stirring rate of the leaching is 200 r / min to 300 r / min.

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