Method for enriching and recovering titanium from titanium-containing blast furnace slag

Abstract

The invention discloses a method for enriching and recovering titanium from titanium-containing blast furnace slag. The method comprises the following steps: treating the titanium-containing blast furnace slag by using mixed acid of hydrochloric acid and organic acid, heating, stirring, and filtering to obtain filter residues and filtrate; the obtained filter residues are continuously added into an alkali solution for impurity removal treatment, and Ti-enriched blast furnace slag is obtained; and adding an alkali solution into the filtrate, and adjusting the pH value of the filtrate to generate Ti (OH) 4 precipitate in the filtrate so as to recover the Ti-containing component in the filtrate. According to the method for enriching and recycling titanium from the titanium-containing blast furnace slag, stepped recycling of titanium resources in the titanium-containing blast furnace slag is achieved through a three-step synergistic process of mixed acid treatment, alkali liquor impurity removal and pH adjustment precipitation. The method is weak in corrosivity, low in equipment requirement, high in environmental friendliness and high in operation safety, impurities in the titanium-containing blast furnace slag can be effectively removed, enrichment of Ti-containing components is achieved, and the method is used for producing high-added-value products such as titanium alloys, titanium metal and photocatalysts.

Description

Technical Field

[0001] This invention belongs to the field of wet treatment technology for titanium-containing blast furnace slag, specifically relating to a method for enriching and recovering titanium from titanium-containing blast furnace slag. Background Technology

[0002] Titanium, a strategic metal with excellent properties such as high strength, corrosion resistance, and high temperature resistance, has irreplaceable core application value in many high-end fields such as aerospace, chemical industry, metallurgy, and biomedicine. However, in the comprehensive mining and smelting process of vanadium-titanium magnetite, approximately 50% of titanium resources do not enter subsequent deep processing stages, but are discharged as titanium oxides with smelting waste, forming a large amount of titanium-containing blast furnace slag. Limited by the current level of recycling technology, the overall utilization rate of titanium resources is not high enough. Therefore, it is crucial to break through the bottleneck of efficient recovery technology for titanium resources in titanium-containing blast furnace slag and transform "solid waste" into "resources".

[0003] To recover titanium resources from titanium-containing blast furnace slag, the relatively mature and widely used process is the "high-temperature carbonization-low-temperature chlorination" process. Although this process has achieved some degree of recovery and utilization of titanium resources from titanium-containing blast furnace slag and promoted industry development, it still reveals several insurmountable technical shortcomings in practical industrial applications: First, the process has extremely high energy consumption; second, the titanium content in the finished carbonized slag is low, with the TiC mass fraction typically only 10%-15%, and the presence of numerous impurities (such as oxides of calcium, magnesium, and silicon) not only reduces the enrichment efficiency of titanium resources but also interferes with subsequent chlorination reactions; third, chlorination efficiency is limited; and fourth, stable operation is difficult.

[0004] In summary, existing titanium resource recovery technologies from titanium-containing blast furnace slag generally suffer from problems such as high energy consumption, low titanium enrichment efficiency, complex processes, or poor environmental performance, and cannot meet the current industry's demand for low-cost, high-efficiency, and low-pollution titanium resource recovery. Therefore, it is urgent to develop a new, green, and efficient method for enriching and recovering titanium resources from titanium-containing blast furnace slag. Summary of the Invention

[0005] To address the shortcomings of the prior art, a method for enriching and recovering titanium from titanium-containing blast furnace slag is provided.

[0006] To achieve the above objectives, the following technical solution is adopted: This invention provides a method for enriching and recovering titanium from titanium-containing blast furnace slag, comprising the following steps: S101. Titanium-containing blast furnace slag is treated with a mixture of hydrochloric acid and organic acid, and after heating and stirring, it is filtered to obtain filter residue and filtrate. S102. The obtained filter residue is further added to an alkaline solution for impurity removal to obtain Ti-enriched blast furnace slag. S103. Add the alkaline solution to the filtrate obtained in step S101, adjust the pH value of the filtrate, so that Ti(OH)4 precipitate is generated in the filtrate, thereby recovering the Ti-containing component in the filtrate.

[0007] In some embodiments, the titanium-containing blast furnace slag is ground to below 200 mesh before proceeding to step S101.

[0008] In some embodiments, the mass ratio of hydrochloric acid to organic acid is 1:3 to 1:6; wherein the concentration of the hydrochloric acid solution is 10wt%-30wt%.

[0009] In some embodiments, the organic acid solution is a mixture of one or more acids selected from oxalic acid, citric acid, formic acid, and acetic acid, and the concentration of the organic acid solution is 5wt%-15wt%.

[0010] In some embodiments, the solid-liquid ratio of titanium-containing blast furnace slag to mixed acid in step S101 is 20 g / L-40 g / L.

[0011] In some embodiments, in step S101, the heating temperature is 50℃-80℃, the stirring time is 1h-3h, and the stirring speed is 100r / min-300r / min.

[0012] In some embodiments, the alkaline solution is selected from NaOH solution or Na2CO3 solution; wherein the concentration of NaOH solution is 10wt%-30wt% and the concentration of Na2CO3 solution is 20wt%-40wt%.

[0013] In some embodiments, the solid-liquid ratio of the filter residue to the alkaline solution in step S102 is 70 g / L-120 g / L.

[0014] In some embodiments, in step S102, the filter residue is added to an alkaline solution and stirred for 1-3 hours at a heating temperature of 80°C-120°C to remove impurities, wherein the stirring speed is 100 r / min-300 r / min.

[0015] In some embodiments, the pH of the filtrate is adjusted to 4-6 in step S103.

[0016] The present invention has the following beneficial technical effects: The present invention provides a method for enriching and recovering titanium from titanium-containing blast furnace slag. This method employs a three-step synergistic process—mixed acid treatment, alkali solution removal, and pH-adjusted precipitation—to achieve the tiered recovery of titanium resources from titanium-containing blast furnace slag. This method is characterized by low corrosiveness, minimal equipment requirements, high environmental friendliness, and strong operational safety. It effectively removes impurities from titanium-containing blast furnace slag, enriching the Ti-containing components for the production of high-value-added products such as titanium alloys, titanium metal, and photocatalysts.

[0017] Mixed acid treatment can selectively dissolve some impurities and partially dissolve titanium components, while alkaline treatment further purifies the titanium-enriched material in the filter residue. pH-adjusted precipitation efficiently recovers titanium components from the filtrate. The overall process forms a closed loop of "enrichment-purification-full recovery", significantly improving the recovery rate of titanium resources.

[0018] Compared with the existing titanium extraction technology of "high temperature carbonization-low temperature chlorination of titanium-containing blast furnace slag", the whole process adopts wet treatment, which greatly reduces energy consumption, can achieve the enrichment of Ti-containing components in titanium-containing blast furnace slag, significantly reduce energy consumption, and is more environmentally friendly. Attached Figure Description

[0019] 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 these drawings without creative effort.

[0020] Figure 1 This is a flowchart of the method for enriching and recovering titanium from titanium-containing blast furnace slag according to the present invention. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be further described in detail below with reference to specific examples and the accompanying drawings.

[0022] It should be understood that the embodiments of the invention shown in the exemplary embodiments are merely illustrative. Although only a few embodiments have been described in detail in this invention, those skilled in the art will readily recognize that various modifications are possible without substantially departing from the teachings of the invention. Accordingly, all such modifications should be included within the scope of the invention. Other substitutions, modifications, variations, and deletions can be made to the design, operating conditions, and parameters of the following exemplary embodiments without departing from the spirit of the invention.

[0023] In view of the above objectives, one aspect of the embodiments of the present invention is as follows: Figure 1 As shown, a method for enriching and recovering titanium from titanium-containing blast furnace slag is proposed. The titanium-containing blast furnace slag can be high-titanium blast furnace slag, in which the titanium dioxide (TiO2) content is usually between 20wt% and 35wt%. For high-titanium blast furnace slag produced from certain specific mineral sources or processes, the TiO2 content can be further increased to about 40wt%.

[0024] The above method includes the following steps: S101. Titanium-containing blast furnace slag is treated with a mixture of hydrochloric acid and organic acid, and after heating and stirring, it is filtered to obtain filter residue and filtrate. S102. The obtained filter residue is further added to an alkaline solution for impurity removal to remove the SiO2 component from the filter residue and obtain Ti-enriched blast furnace slag. S103. Add the alkaline solution to the filtrate obtained in step S101 to adjust the pH of the filtrate, so that Ti 4+ With OH - A hydrolysis reaction occurs to generate Ti(OH)4 precipitate, which is then formed in the filtrate, thereby recovering the Ti-containing component from the filtrate.

[0025] A three-step synergistic process—mixed acid treatment, alkaline purification, and pH-adjusted precipitation—achieves the tiered recovery of titanium resources from titanium-containing blast furnace slag. The mixed acid treatment selectively dissolves some impurities and partially dissolves the titanium components; the alkaline treatment further purifies the titanium concentrate in the filter residue; and the pH-adjusted precipitation efficiently recovers the titanium components from the filtrate. The overall process forms a closed loop of "enrichment-purification-full recovery," significantly improving the titanium resource recovery rate. Compared to traditional high-temperature processes, the entire process utilizes wet treatment, greatly reducing energy consumption and avoiding equipment damage and pollution problems caused by high temperatures, thus combining high efficiency with environmental friendliness.

[0026] In a preferred embodiment of the present invention, titanium-containing blast furnace slag is ground to below 200 mesh before being processed in step S101.

[0027] By refining the blast furnace slag particles to below 200 mesh, the contact area between the slag and the mixed acid is increased, thereby improving the reaction rate and sufficiency during subsequent acid treatment. This results in more thorough dissolution of impurities and more uniform dissolution of titanium components, laying the foundation for subsequent titanium enrichment and recovery. At the same time, it shortens the reaction time and improves the overall process efficiency.

[0028] In a preferred embodiment of the present invention, the mass ratio of hydrochloric acid to organic acid is 1:3 to 1:6; wherein the concentration of hydrochloric acid solution is 10wt%-30wt%.

[0029] The mass ratio of hydrochloric acid to organic acid can be, for example, 1:3, 1:4, 1:5, 1:6, or any range between any two values, preferably 1:3 to 1:4.

[0030] The concentration of the organic acid solution can be, for example, 10, 20, 30% by mass or any range between any two values, preferably 10-20% by mass.

[0031] The mixed acids within this ratio and concentration range can achieve synergistic effects: hydrochloric acid can effectively dissolve alkaline impurities such as calcium and magnesium, while organic acids can assist in dissolving some insoluble impurities and reduce the loss of titanium components through complexation. Optimizing the ratio and concentration of the two can maximize the retention of titanium components (including enriched titanium in the filter residue and recoverable titanium in the filtrate) while ensuring the impurity removal rate, avoiding the problems of high titanium loss rate or incomplete impurity removal when treated with a single acid.

[0032] In a preferred embodiment of the present invention, the organic acid solution is one or more mixed acids selected from oxalic acid, citric acid, formic acid, and acetic acid, and the concentration of the organic acid solution is 5wt%-15wt%.

[0033] The concentration of the organic acid solution can be, for example, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15% by mass or any range between any two values, preferably 5-10% by mass.

[0034] The selected organic acids, such as oxalic acid and citric acid, have good complexing properties and weak acidity. Within this concentration range, they can form stable complexes with titanium ions to reduce precipitation loss during the acid treatment stage, and selectively dissolve impurities such as aluminum and iron in blast furnace slag. Compared with strong organic acids, they can avoid excessive corrosion of equipment and reduce the difficulty of subsequent neutralization treatment, taking into account both reaction efficiency and process feasibility.

[0035] In a preferred embodiment of the present invention, the solid-liquid ratio of titanium-containing blast furnace slag to mixed acid in step S101 is 20 g / L-40 g / L.

[0036] The solid-liquid ratio of titanium-containing blast furnace slag to mixed acid can be, for example, 20 g / L, 25 g / L, 30 g / L, 35 g / L, 40 g / L, or any range between any two values, preferably 20-25 g / L.

[0037] This solid-liquid ratio range ensures sufficient wetting and reaction of the mixed acid with the blast furnace slag, avoiding insufficient acid and incomplete reaction due to an excessively high solid-liquid ratio, or waste of acid and increased subsequent treatment costs due to an excessively low solid-liquid ratio. By optimizing the solid-liquid ratio, efficient utilization of raw materials and reagents can be achieved while ensuring the dissolution of impurities and the effective distribution of titanium components (filter residue and filtrate), thereby reducing process costs.

[0038] In a preferred embodiment of the present invention, in step S101, the heating temperature is 50℃-80℃, the stirring time is 1h-3h, and the stirring speed is 100r / min-300r / min.

[0039] Heating temperatures of 50℃-80℃ can accelerate the reaction rate of the mixed acid and blast furnace slag, while avoiding the volatilization or decomposition of organic acids due to high temperatures; stirring time of 1h-3h and speed of 100-300r / min can ensure uniform mixing of the reaction system, fully dissolve impurities and reduce the accidental precipitation of titanium components caused by excessively high local concentrations. Through parameter synergy, the acid treatment effect is ensured to be stable and controllable.

[0040] The heating temperature can be, for example, 50, 60, 70, 80°C or any range between any two values, preferably 50-70°C; the stirring time can be, for example, 1, 2, 3 h or any range between any two values; the stirring speed can be, for example, 100, 200, 300 r / min or any range between any two values.

[0041] In a preferred embodiment of the present invention, the alkaline solution is selected from NaOH solution or Na2CO3 solution; wherein the concentration of NaOH solution is 10wt%-30wt% and the concentration of Na2CO3 solution is 20wt%-40wt%.

[0042] The concentration of the NaOH solution can be, for example, 10, 20, 30 wt% or any range between any two values, preferably 20-30 wt%.

[0043] The concentration of the Na2CO3 solution can be, for example, 20, 30, 40 wt% or any range between any two values, preferably 30-40 wt%.

[0044] Using NaOH or Na2CO3 solutions as alkaline solutions, the concentration can be specifically used to dissolve SiO2 to generate sodium silicate. Alkaline solutions have high stability and no volatile pollution, and are less expensive than strong alkalis (such as KOH). The sodium silicate generated is easily soluble in water and can be completely separated from titanium-containing slag after filtration.

[0045] In a preferred embodiment of the present invention, the solid-liquid ratio of the filter residue to the alkaline solution in step S102 is 70 g / L-120 g / L.

[0046] In a preferred embodiment of the present invention, in step S102, the filter residue is added to an alkaline solution and stirred for 1-3 hours at a heating temperature of 80°C-120°C to remove impurities, wherein the stirring speed is 100 r / min-300 r / min.

[0047] The heating temperature can be, for example, 80, 85, 90, 95, 100, 105, 110, 105, 120°C or any range between any two values, preferably 100-120°C; the stirring time can be, for example, 1, 2, 3 h or any range between any two values; the stirring speed can be, for example, 100, 200, 300 r / min or any range between any two values.

[0048] Heating temperatures of 80℃-120℃ can promote the reaction rate between the alkaline solution and impurities in the filter residue, especially accelerating the dissolution of sparingly soluble impurities such as silicon and aluminum; stirring time of 1h-3h and speed of 100-300r / min can ensure reaction uniformity, avoid local overheating or incomplete reaction, ensure that the titanium components in the filter residue are deeply purified, and significantly improve the purity of the final titanium concentrate.

[0049] In a preferred embodiment of the present invention, the pH value of the filtrate is adjusted to 4-6 in step S103. The amount of alkali solution added is: alkali solution is gradually added until the pH value of the filtrate is adjusted to 4-6.

[0050] When the pH value is controlled between 4 and 6, the titanium ions (such as Ti) in the filtrate can be contained. 4+ The titanium precipitate is efficiently converted into Ti(OH)4 precipitate, while inhibiting the co-precipitation of other metal ions (such as iron and aluminum ions), thus improving the purity of the titanium precipitate. The reaction conditions in this pH range are mild, the precipitation process is easy to control, and the titanium component can be efficiently recovered by subsequent filtration, which greatly improves the utilization rate of titanium resources in the filtrate.

[0051] The present invention will be further illustrated by the following examples.

[0052] Example 1 Titanium-containing blast furnace slag from a certain factory (its chemical composition is shown in Table 1) was selected and ground to below 200 mesh using a grinding mill. A mixed acid solution was prepared by mixing 20% ​​hydrochloric acid and 10% oxalic acid at a mass ratio of 1:4. 200g of titanium-containing blast furnace slag powder was added to the mixed acid solution at a solid-liquid ratio of 25g / L. The solution was leached at 70℃ and 200r / min for 3 hours, and then filtered to obtain filter residue A and filtrate B.

[0053] Filter residue A was added to a 20% NaOH solution at a solid-liquid ratio of 70 g / L and leached for 2 hours at 100℃ and 200 r / min. Filter residue C was obtained by filtration, with a mass of 82 g. Its chemical composition is shown in Table 2.

[0054] To recover the dissolved Ti in filtrate B 4+ To remove Ti ions, a 20% NaOH solution was added to filtrate B, and the pH was adjusted to 5.4+ The ions precipitated and were filtered to obtain 10g of precipitate with a Ti(OH)4 content of 78%.

[0055] Therefore, by treating titanium-containing blast furnace slag with a mixed acid and NaOH solution, a significant increase in TiO2 content in filter residue C was achieved, nearly doubling the TiO2 content compared to titanium-containing blast furnace slag. Furthermore, the TiO2 content in the filtrate solution... 4+ Ions can be recovered through alkaline solutions, further improving the recovery rate of Ti-containing components.

[0056] Table 1. Main chemical composition of titanium-containing blast furnace slag / %

[0057] Table 2. Main chemical components of filter residue C / %

[0058] Example 2 Titanium-containing blast furnace slag from a certain factory (its chemical composition is shown in Table 1) was selected and ground to below 200 mesh using a grinding mill. A mixed acid solution was prepared by mixing 10% hydrochloric acid and 5% oxalic acid at a mass ratio of 1:6. 200g of titanium-containing blast furnace slag powder was added to the mixed acid solution at a solid-liquid ratio of 20g / L. The solution was leached at 50℃ and 100r / min for 1 hour, and then filtered to obtain filter residue A and filtrate B.

[0059] Filter residue A was added to a 10% NaOH solution at a solid-liquid ratio of 90 g / L and leached for 1 hour at 80°C and 100 r / min. Filter residue C was obtained by filtration, with a mass of 77.1 g. Its chemical composition is shown in Table 3.

[0060] To recover the dissolved Ti in filtrate B 4+ To remove Ti ions, a 10% NaOH solution was added to filtrate B, and the pH was adjusted to 4. 4+ The ions precipitated and were filtered to obtain 8.6g of precipitate with a Ti(OH)4 content of 75.8%.

[0061] Therefore, by treating titanium-containing blast furnace slag with a mixed acid and NaOH solution, a significant increase in TiO2 content in filter residue C was achieved, nearly doubling the TiO2 content compared to titanium-containing blast furnace slag. Furthermore, the TiO2 content in the filtrate solution... 4+ Ions can be recovered through alkaline solutions, further improving the recovery rate of Ti-containing components.

[0062] Table 3. Main chemical components of filter residue C / %

[0063] Example 3 Titanium-containing blast furnace slag from a certain factory (its chemical composition is shown in Table 1) was selected and ground to below 200 mesh using a grinding mill. A mixed acid solution was prepared by mixing 30% hydrochloric acid and 15% oxalic acid at a mass ratio of 1:3. 200g of titanium-containing blast furnace slag powder was added to the mixed acid solution at a solid-liquid ratio of 40g / L. The solution was leached at 80℃ and a rotation speed of 300r / min for 3 hours, and then filtered to obtain filter residue A and filtrate B.

[0064] Filter residue A was added to a 40% Na2CO3 solution at a solid-liquid ratio of 110 g / L and leached for 3 h at 120 °C and 300 r / min. Filter residue C was obtained by filtration, with a mass of 84.3 g. Its chemical composition is shown in Table 4.

[0065] To recover the dissolved Ti in filtrate B 4+ To remove Ti ions, a 40% Na₂CO₃ solution was added to filtrate B, and the pH was adjusted to 6. 4+ The ions precipitated and were filtered to obtain 9.7g of precipitate with a Ti(OH)4 content of 76.7%.

[0066] Therefore, by treating titanium-containing blast furnace slag with a mixed acid and NaOH solution, a significant increase in TiO2 content in filter residue C was achieved, nearly doubling the TiO2 content compared to titanium-containing blast furnace slag. Furthermore, the TiO2 content in the filtrate solution... 4+ Ions can be recovered through alkaline solutions, further improving the recovery rate of Ti-containing components.

[0067] Table 4. Main chemical components of filter residue C / %

[0068] Comparative Example 1 Titanium-containing blast furnace slag from a certain factory (its chemical composition is shown in Table 1) was selected and crushed to below 200 mesh.

[0069] 50 tons of crushed titanium-containing blast furnace slag were directly loaded into a three-phase AC electric furnace, along with 6.5 tons of coke powder. The furnace was smelted at 1500℃-1600℃ for 2 hours before slag removal. The slag was then water-quenched, dried, and ground to obtain the finished carbide slag (its chemical composition is shown in Table 5). The titanium carbide content was 14.92%.

[0070] Table 5. Main chemical components of finished carbonized slag / %

[0071] The above are exemplary embodiments disclosed in this invention. However, it should be noted that various changes and modifications can be made without departing from the scope of the embodiments of this invention as defined by the claims. Although the elements disclosed in the embodiments of this invention may be described or claimed individually, they may be understood as multiple unless explicitly limited to a singular number.

[0072] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention (including the claims) is limited to these examples. Within the framework of the invention, technical features of the above embodiments or different embodiments can be combined, and many other variations of different aspects of the invention exist, which are not provided in the details for the sake of brevity. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the invention should be included within the protection scope of the invention.

Claims

1. A method for recovering titanium by enrichment from a titanium-containing blast furnace slag, characterized in that, The method comprises the following steps: S101, treating the titanium-containing blast furnace slag with a mixed acid of hydrochloric acid and organic acid, and filtering the treated slag to obtain a filter residue and a filtrate; S102, adding the filter residue to an alkali solution to remove impurities and obtain a Ti-rich blast furnace slag; S103, adding the alkali solution to the filtrate obtained in step S101 to adjust the pH value of the filtrate, so that Ti(OH)4 precipitates are generated in the filtrate, thereby recovering the Ti-containing components in the filtrate.

2. The method for recovering titanium by concentration according to claim 1, wherein The titanium-containing blast furnace slag is ground to 200 mesh or less before being treated in step S101.

3. The method for recovering titanium by concentration according to claim 1, wherein The mass ratio of the hydrochloric acid to the organic acid is 1:3-1:6; the concentration of the hydrochloric acid solution is 10wt%-30wt%.

4. The method for recovering titanium by concentration according to claim 3, characterized in that, The organic acid solution is a mixed acid selected from one or more of oxalic acid, citric acid, formic acid, and acetic acid, and the concentration of the organic acid solution is 5wt%-15wt%.

5. The method for recovering titanium by concentration according to claim 3, wherein The solid-liquid ratio of the titanium-containing blast furnace slag to the mixed acid in step S101 is 20g / L-40g / L.

6. The method for recovering titanium by concentration according to claim 1, wherein In step S101, the heating temperature is 50℃-80℃, the stirring time is 1h-3h, and the stirring speed is 100r / min-300r / min.

7. The method for recovering titanium by concentration according to claim 1, wherein The alkali solution is selected from a NaOH solution or a Na2CO3 solution; the concentration of the NaOH solution is 10wt%-30wt%, and the concentration of the Na2CO3 solution is 20wt%-40wt%.

8. The method for recovering titanium by concentration according to claim 1, wherein The solid-liquid ratio of the filter residue to the alkali solution in step S102 is 70g / L-120g / L.

9. The method for recovering titanium by concentration according to claim 8, wherein In step S102, the filter residue is added to the alkali solution, and the impurities are removed at a heating temperature of 80℃-120℃ and a stirring time of 1h-3h, wherein the stirring speed is 100r / min-300r / min.

10. The method for recovering titanium by concentration according to claim 1, wherein In step S103, the pH value of the filtrate is adjusted to 4-6.

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