Method for improving titanium recovery rate of vanadium titano-magnetite

Abstract

The invention relates to the technical field of comprehensive recycling of vanadium titano-magnetite, and provides a method for improving the titanium recovery rate of the vanadium titano-magnetite, which comprises the following steps: carrying out acid leaching treatment on a vanadium titano-magnetite sample, and carrying out solid-liquid separation to obtain leaching residues and titanium-containing leaching liquid; the leaching residues are washed and then subjected to size mixing, desulfurization flotation and titanium flotation operation with only addition of a collecting agent are sequentially carried out to obtain titanium rough concentrate, and then the titanium rough concentrate is dried and subjected to electric separation to obtain a titanium concentrate product; and heating the titanium-containing leachate to carry out a titanium precipitation reaction, precipitating titanium in the titanium-containing leachate, recovering evaporated acid, and carrying out solid-liquid separation to obtain a titanium dioxide product. According to the method, through organic combination of chemical leaching pretreatment, physical separation and solution recovery, the total recovery rate of titanium in the micro-fine particle vanadium titano-magnetite is increased, meanwhile, the technological process is simplified, and the dependence on flotation reagents and the overall operation cost are reduced.

Description

Technical Field

[0001] This invention relates to the field of comprehensive recycling technology of vanadium-titanium magnetite, and in particular to a method for improving the titanium recovery rate of vanadium-titanium magnetite. Background Technology

[0002] Vanadium-titanium magnetite is an important strategic mineral resource in my country, rich in vanadium, iron, titanium, and other key metallic elements. The overall recovery rate of the main valuable elements in this resource is generally low, with titanium recovery being particularly poor, resulting in significant resource waste. The main reason for the low recovery rate lies in the complex and closely intergrowth relationship of valuable minerals in the ore, and the poor recovery effect of existing beneficiation processes on fine-grained minerals. In particular, ilmenite and gangue minerals (such as titanopyroxene) have extremely similar surface physicochemical properties, making effective separation difficult using conventional physical sorting processes. This results in this portion of material often being directly sent to tailings, leading to severe titanium resource loss.

[0003] Existing recovery methods employ processes such as pre-classification-strong magnetic flotation and flocculation-strong magnetic flotation. These methods utilize pre-classification, flocculation, or enhanced dispersion, supplemented by targeted separation equipment and flotation reagent combinations, to mitigate the interference of fine-particle slime. However, to obtain qualified products in the flotation stage, these methods often require the addition of large amounts of inhibitors, modifiers, or dispersants, resulting in high reagent consumption, high costs, and typically lengthy overall processes with high operating expenses.

[0004] Therefore, there is an urgent need for a method to improve the titanium recovery rate of vanadium-titanium magnetite, which can simplify the overall recycling process, reduce reagent dependence, and improve the titanium recovery rate. Summary of the Invention

[0005] To address the problems of low overall recovery rate, long overall recovery process, and high reagent dependence in existing technologies for vanadium-titanium magnetite, this invention proposes a method to improve the titanium recovery rate of vanadium-titanium magnetite, comprising: Step a: Acid leaching is performed on the vanadium-titanium magnetite sample, and after solid-liquid separation, leaching residue and titanium-containing leachate are obtained; Step b: After washing the leaching residue, the slurry is prepared and subjected to desulfurization flotation and titanium flotation with only the addition of a collector to obtain titanium crude concentrate. Then, the titanium crude concentrate is dried and electrostatically separated to obtain titanium concentrate product. Step c: Heat the titanium-containing leachate to carry out a titanium precipitation reaction, so that the titanium in it precipitates and the evaporated acid is recovered. After solid-liquid separation, titanium dioxide product is obtained.

[0006] In some embodiments, step a includes: The vanadium-titanium magnetite sample was mixed with the acid solution and stirred at a speed of 300-400 r / min for 0.5-1.0 hours at a temperature of 50-70℃. The acid solution is hydrochloric acid or nitric acid solution, and the amount of acid solution added is determined based on a hydrogen ion concentration of 3-5 mol / L.

[0007] In some embodiments, step b includes: The leaching residue is washed until the calcium ion concentration in the washing solution is below 0.1 g / L, the magnesium ion concentration is below 0.2 g / L, and the pH value reaches 1.5-2; The washed leaching residue is mixed with water to prepare a slurry with a mass concentration of 30-40%.

[0008] In some embodiments, step b further includes: Add 400-500 g / t of titanium collector to the desulfurization flotation tailings for flotation.

[0009] In some embodiments, step b, the electrical selection, includes: The dried titanium rough concentrate is subjected to one roughing and one scavenging process in sequence.

[0010] In some embodiments, the coarse selection includes: The dried titanium concentrate was roughed under the conditions of 20~25kV voltage and 100~130r / min drum rotation speed.

[0011] In some embodiments, the scanning includes: Detecting the titanium dioxide content in roughing tailings; If the titanium dioxide content is greater than 10%, the sweeping should be carried out at 110-120% of the coarse selection voltage and rotation speed; If the titanium dioxide content is no more than 10%, the sweeping should be carried out at 85-95% of the coarse selection voltage and rotation speed.

[0012] In some embodiments, step c includes: The titanium-containing leachate is heated to 90-110°C to carry out the titanium precipitation reaction.

[0013] In some embodiments, step c further includes: After solid-liquid separation, the separated titanium mother liquor is cooled and crystallized to obtain a mixed salt product.

[0014] In some embodiments, step c further includes: The evaporated acid is returned to step a for acid leaching treatment.

[0015] This invention offers at least the following advantages: It proposes a method to improve the titanium recovery rate of vanadium-titanium magnetite. By organically combining chemical leaching pretreatment with physical separation and solution recovery, the total titanium recovery rate in fine-grained vanadium-titanium magnetite is improved, while the process is simplified, reducing dependence on flotation reagents and overall operating costs. Specifically, in step a, acid leaching of the vanadium-titanium magnetite selectively leaches some titanium elements, altering the physicochemical properties of the leaching residue and effectively reducing the negative impact of fine-grained slime. This prevents subsequent separation processes from being interfered with by slime, thus overcoming the separation difficulties caused by similar mineral surface properties. In step b, based on the pretreated leaching residue, only a collector needs to be added during titanium flotation without the use of any inhibitors or modifiers, simplifying the flotation reagent system, solving the problems of high reagent consumption and high costs in existing technologies, and further shortening the process. By drying and electrostatically separating the titanium rough concentrate, high-grade titanium concentrate products can be obtained efficiently, ensuring the quality of the final product. In step c, the titanium-containing leachate is heated to precipitate titanium and the evaporated acid is recovered. The titanium in the leachate is fully recovered in the form of high-purity titanium dioxide, which further improves the overall recovery rate of titanium and realizes the recycling of acid, reducing raw material consumption and waste emissions. Attached Figure Description

[0016] 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 embodiments can be obtained based on these drawings without creative effort.

[0017] Figure 1 A flowchart of a method for improving titanium recovery rate in vanadium-titanium magnetite according to an embodiment of the present invention; Figure 2 Another flowchart of a method for improving titanium recovery from vanadium-titanium magnetite, provided as an embodiment of the present invention. Detailed Implementation

[0018] The following describes embodiments of the present invention. However, it should be understood that the disclosed embodiments are merely examples, and other embodiments may take various alternative forms.

[0019] Furthermore, it should be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article, or apparatus that comprises a list of elements may include not only those elements but also elements not expressly listed or inherent to such process, method, article, or apparatus.

[0020] One or more embodiments of the present invention will now be described with reference to the accompanying drawings.

[0021] To achieve the above objectives, the present invention provides an embodiment of a method for improving the titanium recovery rate of vanadium-titanium magnetite. The method for improving the titanium recovery rate of vanadium-titanium magnetite includes: Step a: Acid leaching is performed on the vanadium-titanium magnetite sample, and after solid-liquid separation, leaching residue and titanium-containing leachate are obtained.

[0022] In this invention, vanadium-titanium magnetite samples refer to materials obtained after crushing, grinding, and preliminary iron beneficiation, with titanium recovery as the primary objective. The particle size distribution of this material is dominated by particles smaller than 0.038 mm, with extremely fine slime (smaller than 0.01 mm) accounting for 20-25%, which hinders conventional flotation. The typical particle size distribution of refractory fine-grained vanadium-titanium magnetite is shown in Table 1 below. Table 1

[0023] Among them, particles smaller than -0.038mm account for more than 70%, especially ultrafine particles of -0.01mm, which account for 20-25%.

[0024] Acid leaching refers to the process of using strong inorganic acids to chemically react with specific minerals in ores under heating and stirring conditions. In this invention, the acid leaching process involves titanium-containing minerals and some soluble gangue. The result is that some titanium enters the solution in ionic form, reducing the content of fine-grained materials through dissolution or alteration of surface properties, and optimizing the particle size distribution of solid residues towards coarser particles.

[0025] In some embodiments, the vanadium-titanium magnetite sample is mixed and stirred with an acid solution at a stirring speed of 300-400 r / min and reacted at a temperature of 50-70°C for 0.5-1.0 hours; wherein the acid solution is hydrochloric acid or nitric acid solution, and the amount of acid solution added is determined by a hydrogen ion concentration of 3-5 mol / L.

[0026] The process involves mixing and stirring a vanadium-titanium magnetite sample with an acid solution. First, an acid solution of the required concentration needs to be prepared. For example, industrial-grade hydrochloric acid or nitric acid can be used. The concentration of the acid solution (or the amount added) is controlled based on the hydrogen ion concentration to ensure sufficient reactivity and consistency. A predetermined mass of finely granulated vanadium-titanium magnetite sample, the metered acid solution, and an appropriate amount of water are added to an acid-resistant reaction vessel, and mechanical stirring is initiated.

[0027] Controlling the stirring speed within the range of 300-400 r / min ensures sufficient contact between the mineral particles and the acid solution, preventing solid sedimentation while avoiding excessive shear force that could cause the already formed fine mud to resuspend or become encapsulated. Simultaneously, maintaining the reaction system temperature between 50-70℃ effectively guarantees sufficient reaction kinetics, promoting titanium leaching and the dissolution and transformation of fine particles, while preventing excessive acid volatilization and high energy consumption. The reaction is carried out at 50-70℃ and a stirring speed of 300-400 r / min for 0.5-1.0 hours. After the reaction, solid-liquid separation is performed, for example, by suction filtration or pressure filtration, to obtain the solid leaching residue and the liquid titanium-containing leachate.

[0028] For the fine-grained vanadium-titanium magnetite mineral material shown in Table 1, the leaching residue and leachate obtained after acid leaching treatment are analyzed. The specific particle size composition of the leaching residue is shown in Table 2 below. Table 2

[0029] Comparing Tables 1 and 2, it can be seen that the content of ultrafine mud with a particle size of less than 0.01 mm has decreased significantly, from 20-25% in the original ore to 1-2%, and the reduction rate of ultrafine mud can reach 92%, indicating that acid leaching treatment has a significant effect on reducing fine mud.

[0030] Preferably, the titanium leaching rate obtained from step a is 25-35%, and the material reduction rate of -0.01mm is 80-95%.

[0031] In one specific embodiment, 500g of fine-grained vanadium-titanium magnetite mineral material with the particle size distribution shown in Table 1 was mixed with 420g of 60% nitric acid and 580g of water. The mixture was reacted in a water bath at 50℃ for 40min at a stirring rate of 300r / min. After reaction, the mixture was filtered to obtain approximately 401g of leaching residue and 935mL of leachate. Analysis showed that the titanium ion concentration in the leachate was 16.3g / L, and the titanium dioxide grade in the leaching residue was 19%, resulting in a titanium leaching rate of 25.1%.

[0032] Step a above involves acid leaching of vanadium-titanium magnetite, selectively leaching out some titanium elements, altering the physicochemical properties of the leaching residue, effectively reducing the negative impact of fine-grained slime, and ensuring that the subsequent sorting process is free from slime interference, thereby overcoming the separation problem caused by the similarity of mineral surface properties.

[0033] Step b: After washing the leaching residue, adjust the slurry and perform desulfurization flotation and titanium flotation with only collector added in sequence to obtain titanium rough concentrate. Then, dry the titanium rough concentrate and electrostatically separate it to obtain titanium concentrate product.

[0034] Washing the leaching residue can effectively remove soluble salts (such as calcium salts and magnesium salts) and residual acid adhering to the surface of mineral particles, thus preventing these soluble impurity ions from interfering with the action of subsequent flotation reagents and increasing unnecessary reagent consumption.

[0035] As an optional embodiment, the washing process continues until the final eluent has a calcium ion concentration below 0.1 g / L, a magnesium ion concentration below 0.2 g / L, and a pH value of 1.5–2. Reaching this endpoint indicates that these soluble impurity ions have been substantially removed and the eluent can be used for subsequent desulfurization flotation and titanium flotation operations, avoiding interference with the collectors added during flotation. After washing, the leaching residue is mixed with water to prepare a suitable flotation pulp concentration. For example, a pulp with a mass concentration of 30–40% is prepared, a concentration range that ensures good pulp flowability and bubble dispersion.

[0036] Desulfurization flotation is used to pre-remove sulfide minerals that may interfere with subsequent titanium flotation, for example, by using diesel oil as a collector and pine oil as a frother.

[0037] In some embodiments, 400-500 g / t of titanium collector is added to the desulfurization flotation tailings for flotation. Due to the acid leaching treatment in step a, which reduces most of the ultrafine slime and alters the mineral surface properties, the difference in floatability between ilmenite and gangue (such as titanopyroxene) is amplified, significantly reducing slime interference and effectively simplifying the flotation process. Therefore, no inhibitors, dispersants, or pH adjusters (such as large amounts of sulfuric acid) are needed during the flotation process to suppress gangue or adjust the pulp pH, effectively solving the problems of complex reagent formulations and high costs. Preferably, the TiO2 content in the titanium concentrate obtained from the flotation process is 35-40%.

[0038] As a specific embodiment, 300 grams of the aforementioned leaching residue was taken and washed until the Ca in the final wash solution was reduced. 2+ 0.08 g / L, Mg 2+ After adjusting the concentration to 0.15 g / L and pH to 1.7, 300 g of water was added to prepare the slurry. The slurry was then subjected to conventional desulfurization flotation, for example, using 30 g / t diesel oil as a collector and 10 g / t pine oil as a frother. Then, conventional titanium collectors, such as MOS and RST series collectors, were added to the desulfurization tailings at a dosage of 450 g per ton of leaching residue. After stirring, aeration flotation was performed to obtain a titanium rough concentrate. Testing showed that the titanium dioxide grade of the obtained titanium rough concentrate reached 37.8%, and the titanium recovery rate in the flotation operation reached 90.1%.

[0039] After obtaining the titanium rough concentrate, it can be further purified by electrostatic separation. Electrostatic separation is a method of separating minerals based on differences in conductivity in a high-voltage electric field. As a feasible embodiment, electrostatic separation includes sequentially performing a roughing and a scavenging process on the dried titanium rough concentrate.

[0040] Specifically, the titanium rough concentrate is dried at 100-105℃ until the moisture content is below 2%, effectively reducing the interference of moisture on electrostatic separation. The dried titanium rough concentrate is then roughed under conditions of 20-25kV voltage and drum rotation speed of 100-130r / min. Under these conditions, ilmenite with better electrical conductivity tends to be adsorbed and carried away by the drum, while non-conductive gangue is repelled under the influence of the electric field.

[0041] Scavenging is performed on the roughing tailings, and its operating parameters can be intelligently optimized according to the grade of the roughing tailings to achieve a balance between recovery rate and grade. As a specific embodiment, scavenging includes: detecting the titanium dioxide content in the roughing tailings; if the content is greater than 10%, it indicates that the tailings still contain a significant amount of recoverable ilmenite. In this case, the field strength and rotation speed are increased, and scavenging is performed at 110-120% of the roughing voltage and rotation speed to enhance separation and improve recovery rate; if the content is not greater than 10%, it indicates that the tailings grade is already low. In this case, the field strength and rotation speed are reduced, and scavenging is performed at 85-95% of the roughing voltage and rotation speed to avoid carrying too much gangue into the concentrate, thus ensuring the final concentrate grade. Preferably, the TiO2 content in the obtained titanium concentrate is above 46.5%, and the product quality meets the mainstream market grade.

[0042] In one specific embodiment, the roughing tailings were roughed at 23.5 kV and 120 r / min, yielding a roughing tailings grade of 7.4%. Since its grade was less than 10%, the scavenging voltage and rotation speed were adjusted to approximately 93% of the roughing voltage, i.e., 21.8 kV and 111.6 r / min. Finally, the concentrate products were combined to obtain a qualified titanium concentrate with a titanium dioxide grade of 47.1%, achieving an electrostatic separation recovery rate of 87.7%.

[0043] Step b above, based on the pretreated leaching residue, only requires the addition of a collector in the titanium flotation operation without the use of any inhibitors or modifiers. This simplifies the flotation reagent system, solves the problems of high reagent consumption and high cost in existing technologies, and further shortens the process. By drying and electrostatically separating the titanium rough concentrate, high-grade titanium concentrate products can be obtained efficiently, ensuring the quality of the final product.

[0044] Step c: Heat the titanium-containing leachate to carry out a titanium precipitation reaction, so that the titanium in it precipitates and the evaporated acid is recovered. After solid-liquid separation, titanium dioxide product is obtained.

[0045] Heating a titanium-containing acidic solution promotes the hydrolysis of titanium ions, precipitating them as metatitanic acid or its hydrate, which is then calcined to obtain titanium dioxide. During the heating process, some of the acid (such as hydrochloric acid and nitric acid) evaporates along with the water.

[0046] In one feasible embodiment, the titanium-containing leachate obtained in step a is heated to 90-110°C to carry out a titanium precipitation reaction. At this temperature, the hydrolysis rate of titanium is accelerated, and the evaporation rate of the acid is also suitable. The evaporated gaseous acid-water mixture is collected and condensed and recovered using a condenser to obtain regenerated acid. In some embodiments, this regenerated acid can be returned to step a for acid leaching treatment for recycling, reducing the consumption of fresh acid.

[0047] In one specific embodiment, 500 mL of the leachate obtained in step a, with a titanium concentration of 16.3 g / L, was taken and heated to 105°C. The evaporated acid mist was collected and condensed. Heating was stopped when the solution volume decreased by approximately 30%, at which point the titanium had fully precipitated. After filtration, washing, and drying at 200°C, a titanium dioxide product was obtained with a purity (titanium dioxide content) of 95.4%, and a titanium precipitation recovery rate of 99.1% from solution to product. Simultaneously, the recovered acid can be added to a new leaching process.

[0048] Step c above involves heating the titanium-containing leachate to precipitate titanium and recovering the evaporated acid. This fully recovers the titanium in the leachate as high-purity titanium dioxide, further improving the overall recovery rate of titanium. Moreover, it enables the recycling of acid, reduces raw material consumption and waste emissions, and enhances the economic efficiency and environmental friendliness of the process.

[0049] The above-mentioned method for improving the titanium recovery rate of vanadium-titanium magnetite improves the total titanium recovery rate in fine-grained vanadium-titanium magnetite by organically combining chemical leaching pretreatment, physical sorting, and solution recovery. At the same time, it simplifies the process flow and reduces the dependence on flotation reagents and the overall operating cost.

[0050] To further understand the method for improving titanium recovery in vanadium-titanium magnetite according to the present invention, the following detailed description is provided in specific embodiments. (Reference) Figure 1-2 The raw material used was a fine-grained vanadium-titanium magnetite sample with a TiO2 content of 20.3%. The specific particle size distribution is shown in Table 3. Table 3

[0051] Example 1 Step a, acid leaching treatment Take 500g of the above raw materials and add them together with 420g of 60% nitric acid and 580g of water into a reaction vessel. Turn on the mechanical stirrer and control the stirring speed at 300r / min. Perform acid leaching treatment at 50℃ for 40 minutes. After the reaction is completed, perform solid-liquid separation to obtain 401g of leaching residue and 935ml of leaching solution.

[0052] The concentration of titanium ions in the leachate was 16.3 g / L, and the titanium dioxide content in the leaching residue was 19%. The calculated titanium leaching rate was 25.1%. Particle size analysis of the obtained leaching residue was performed, and the results are shown in Table 4. Table 4

[0053] As can be seen from the comparison between Table 3 and Table 4, after acid leaching treatment, the content of -0.01mm ultrafine particles in the leaching residue decreased from 18.3% in the raw material to 2.0%, with a reduction rate of approximately 88.8%.

[0054] Step b: Leachate sorting Take 300g of the leaching residue obtained in step a, add water and wash until the Ca in the final washing solution is clear. 2+ The content is 0.09 g / L, Mg 2+ The content is less than 0.2 g / L and the pH is 1.5.

[0055] The washed leaching residue was mixed with 600g of water to prepare a slurry with a mass concentration of 33%, and then subjected to flotation. First, desulfurization flotation was carried out: diesel oil (30g / t leaching residue) and pine oil (10g / t leaching residue) were added in sequence, stirred for 3 minutes, and then the bubbles were skimmed off to obtain sulfur concentrate.

[0056] Subsequently, titanium flotation was performed on the desulfurization flotation tailings: only titanium collector (450 g / t leaching residue) was added, and after stirring for 5 minutes, aeration flotation was carried out to obtain titanium rough concentrate. The titanium dioxide content of this titanium rough concentrate was 37.8%, and the titanium recovery rate of this stage of titanium flotation was 90.1%.

[0057] The obtained titanium rough concentrate was dried at 105℃ to reduce its moisture content to 1.7%. Then, electrostatic separation was performed: first, a roughing process was conducted at 23.5kV and a drum speed of 120r / min; the roughing tailings were tested, and their titanium dioxide content was found to be 7.4%. Subsequently, considering that the roughing tailings grade was less than 10%, the scavenging voltage and drum speed were adjusted to approximately 85% of the roughing conditions (i.e., 20kV and 102r / min) to scaveng the roughing tailings. The roughing concentrate and scavenging concentrate were combined to obtain the final titanium concentrate product. The titanium dioxide content of this titanium concentrate product was 47.1%, and the titanium recovery rate of this electrostatic separation operation was 87.7%.

[0058] Step c, leachate treatment Take 500 ml of the leachate obtained in step a and heat it to 105 °C for titanium precipitation. Collect the evaporated acid mist and condense it for recovery. Stop heating when the solution volume evaporates to about 70% of its original volume. Then perform solid-liquid separation to obtain a solid precipitate and titanium precipitation mother liquor. Dry the solid precipitate at 200 °C to obtain titanium dioxide product with a titanium dioxide content of 95.4%. The titanium recovery rate of this titanium precipitation operation is 99.1%. The titanium precipitation mother liquor can be cooled and crystallized to obtain mixed nitrate byproducts.

[0059] After the complete process of steps a to c above, the following were finally obtained from 500g of raw material: (1) 127g of titanium concentrate with a titanium dioxide content of 47.1%; and (2) 26g of titanium dioxide product with a titanium dioxide content of 95.4%. The total recovery rate of titanium in the whole process was calculated to be 84.04%.

[0060] Example 2 The main difference between this embodiment and Embodiment 1 is that hydrochloric acid was used for the acid leaching treatment, and some parameters were adjusted accordingly.

[0061] Step a, acid leaching treatment 500g of the same raw material as in Example 1 was added to a reaction vessel along with 500g of 30% hydrochloric acid and 500g of water. Acid leaching was performed for 40 minutes at 50℃ and 300 rpm with stirring. After solid-liquid separation, 395g of leaching residue and 942ml of leaching solution were obtained. The titanium ion concentration in the leaching solution was 18.1g / L, and the titanium dioxide content in the leaching residue was 18.1%. The calculated titanium leaching rate was 29.7%. The particle size distribution of the leaching residue is shown in Table 5. Table 5

[0062] As can be seen from the comparison between Table 3 and Table 5, after acid leaching treatment, the content of -0.01mm ultrafine particles in the leaching residue decreased from 18.3% in the raw material to 3.2%, with a reduction rate of approximately 82.5%.

[0063] Step b: Leachate sorting Take 300g of leaching residue and wash until the endpoint (Ca of the last wash solution). 2+ 0.06 g / L, Mg 2+<0.11 g / L, pH=1.8), followed by the addition of water to prepare a slurry with a mass concentration of 33%. Subsequent flotation and electrostatic separation steps were the same as in Example 1, with the titanium collector dosage being 450 g / t. The resulting titanium rough concentrate had a titanium dioxide content of 36.9%, and the titanium recovery rate in the titanium flotation operation was 89.7%. The electrostatic roughing conditions were 23.5 kV and 120 r / min, with a roughing tailings grade of 7.8%. The scavenging conditions were adjusted to 95% of the roughing conditions (22.3 kV and 114 r / min). The final titanium concentrate had a titanium dioxide content of 46.9%, and the titanium recovery rate in the electrostatic separation operation was 86.1%.

[0064] Step c, leachate treatment The procedure was the same as in Example 1. The titanium dioxide product obtained had a titanium dioxide content of 95.8%, and the titanium recovery rate of the titanium precipitation process was 99.2%. The mother liquor from the titanium precipitation was crystallized to obtain a mixed chloride product.

[0065] After the complete process of steps a to c above, the following were finally obtained from 500g of raw material: (1) titanium concentrate: 117.5g, titanium dioxide content 46.9%; (2) titanium dioxide product: 31.5g, titanium dioxide content 95.8%. The total recovery rate of titanium in the whole process was calculated to be 83.7%.

[0066] Example 3 The difference between this embodiment and Embodiment 1 is that different concentrations of nitric acid were used, and the leaching temperature and time were adjusted.

[0067] Step a, acid leaching treatment 500g of the same raw material as in Example 1 was added to a reaction vessel along with 500g of 30% nitric acid and 500g of water. Acid leaching was performed for 30 minutes at 60℃ and 300 rpm with stirring. After solid-liquid separation, 398g of leaching residue and 943ml of leaching solution were obtained. The titanium ion concentration in the leaching solution was 16.4g / L, and the titanium dioxide content in the leaching residue was 19.1%. The calculated titanium leaching rate was 25.4%. The particle size distribution of the leaching residue is shown in Table 6. Table 6

[0068] As can be seen from the comparison between Table 3 and Table 6, after acid leaching treatment, the content of -0.01mm ultrafine particles in the leaching residue decreased from 18.3% in the raw material to 1.6%, with a reduction rate of approximately 91.3%.

[0069] Step b: Leachate sorting Take 300g of leaching residue and wash until the endpoint (Ca of the last wash solution). 2+ 0.05 g / L, Mg 2+<0.09 g / L, pH=2.0), and then water was added to prepare a slurry with a mass concentration of 33%. The subsequent flotation steps were the same as in Example 1, and the titanium dioxide content of the obtained titanium crude concentrate was 37.2%, with a titanium recovery rate of 90.7% in the titanium flotation operation.

[0070] During electrostatic separation, the roughing conditions were 20.5 kV and 130 r / min, yielding a roughing tailings grade of 14.5%. Given that the roughing tailings grade was greater than 10%, the scavenging voltage and drum speed were adjusted to 120% of the roughing conditions (24.6 kV and 156 r / min). The final titanium concentrate had a titanium dioxide content of 47.0%, and the titanium recovery rate from electrostatic separation was 89.8%.

[0071] Step c, leachate treatment The procedure was the same as in Example 1. The resulting titanium dioxide product had a titanium dioxide content of 95.1%, and the titanium recovery rate in the titanium precipitation process was 99.2%.

[0072] After the complete process of steps a to c above, the following were finally obtained from 500g of raw material: (1) titanium concentrate: 131.2g, titanium dioxide content 47.0%; (2) titanium dioxide product: 26.9g, titanium dioxide content 95.1%. The total recovery rate of titanium in the whole process was calculated to be 86.0%.

[0073] Example 4 Step a, acid leaching treatment Take 500g of fine-grained vanadium-titanium magnetite raw material (TiO2 20.3%, particle size as per Table 3), mix with sufficient hydrochloric acid, and control the initial acid solution H... + The concentration was approximately 5 mol / L. Mechanical stirring was started, and the speed was controlled at 400 r / min. Acid leaching was performed for 1.0 hour in a 70℃ water bath. After solid-liquid separation, leaching residue and leachate were obtained. The calculated titanium leaching rate was approximately 28%. The content of -0.01 mm particles in the leaching residue was significantly reduced.

[0074] Step b: Leachate sorting Wash the leaching residue to the required endpoint. Mix the washed leaching residue with water at a mass ratio of 1:1.5 (e.g., 300g leaching residue to 450g water) to prepare a slurry with a mass concentration of approximately 40%. Subsequent desulfurization flotation is performed as before. During titanium flotation, increase the titanium collector dosage to 500g / t (leaching residue). Obtain titanium rough concentrate.

[0075] After drying, the titanium rough concentrate is subjected to electrostatic separation. Roughing is carried out at 24kV and a drum rotation speed of 125r / min. Scavenging is performed by adjusting the voltage and drum rotation speed to 110% of the roughing conditions (26.4kV and 137.5r / min) based on the grade of the roughing tailings (e.g., 11%). Finally, qualified titanium concentrate is obtained.

[0076] Step c, leachate treatment The leachate was heated to 110°C to carry out a titanium precipitation reaction, and the evaporated acid was recovered. High-purity titanium dioxide product was obtained. The mother liquor from the titanium precipitation was then subjected to crystallization treatment.

[0077] The overall titanium recovery rate remained stable at over 82% throughout the process, demonstrating the effectiveness of the parameters near their upper limit.

[0078] Example 5 Step a, acid leaching treatment Take 500g of raw material, mix it with hydrochloric acid, and control the initial acid concentration (H). + The concentration was 3.0 mol / L. The reaction was carried out at 50℃ and 300 r / min for 0.5 hours with stirring. After solid-liquid separation, leaching residue and leachate were obtained. The titanium leaching rate was approximately 22%. The particle size of the leaching residue was optimized.

[0079] Step b: Leachate sorting Wash the leaching residue to the required endpoint. Mix the washed leaching residue with water at a mass ratio of 1:2.33 (e.g., 300g leaching residue to 700g water) to prepare a slurry with a mass concentration of approximately 30%. Subsequent desulfurization flotation is performed as before. During titanium flotation, the titanium collector dosage is set to 400g / t (leaching residue). A titanium rough concentrate is obtained.

[0080] After drying, the titanium rough concentrate is subjected to electrostatic separation. The roughing is carried out at a voltage of 20kV and a drum rotation speed of 100r / min. The scavenging is adjusted by adjusting the voltage and drum rotation speed (24kV and 120r / min) according to 120% of the roughing tailings grade (e.g., 12%), and finally obtaining qualified titanium concentrate.

[0081] Step c, leachate treatment The leachate was heated to 90°C to induce a titanium precipitation reaction, and the evaporated acid was recovered. High-purity titanium dioxide was obtained.

[0082] The total titanium recovery rate can still reach about 80% throughout the entire process, which proves the effectiveness of the parameters near the lower limit and the wide adaptability of the process.

[0083] Comparative Example 1 (used to illustrate the adverse consequences caused by acid leaching temperature exceeding the range of the present invention) Step a, acid leaching treatment 500g of finely granulated vanadium-titanium magnetite (composition same as in Example 1) was added to a reaction vessel along with 420g of 60% nitric acid and 580g of water. Mechanical stirring was started, with the stirring speed controlled at 300 rpm, but the water bath temperature was increased to 90°C. The reaction was carried out for 40 minutes. After the reaction, solid-liquid separation was performed, yielding 411g of leaching residue and 942ml of leaching solution.

[0084] Testing revealed that the titanium ion concentration in the leachate was only 0.3 g / L, and the titanium dioxide content in the leaching residue was 24.7%. Calculations showed that the titanium leaching rate was as low as 0.3%. Particle size analysis of the obtained leaching residue is shown in Table 7. Table 7

[0085] A comparison of Tables 3 and 7 shows that after acid leaching at 90℃, the content of -0.01mm particles in the leaching residue did not decrease significantly compared to the raw material (18.3%), and even slightly increased. This indicates that excessively high leaching temperatures not only failed to achieve selective leaching of titanium, but also completely failed to eliminate ultrafine slime and optimize particle size distribution. Therefore, subsequent sorting experiments were terminated. This comparative example demonstrates the necessity of controlling the acid leaching temperature within the range of 50~70℃ in this invention.

[0086] Comparative Example 2 (used to illustrate that if the washing operation in step b is omitted after completing step a, it will lead to problems in subsequent flotation) (The effect deteriorated rapidly) Step a, acid leaching treatment The operating conditions were exactly the same as in Example 1: 500g of raw material was leached with nitric acid at 50°C for 40 minutes. After solid-liquid separation, a leachate (Ti: 16.3g / L) and a leaching residue (TiO2: 19.0%) were obtained. The particle size analysis of the leaching residue is shown in Table 8 below. Table 8

[0087] A comparison of Tables 3 and 8 shows that the content of -0.01mm particles decreased to 2.0%, and the titanium leaching rate was 25.1%.

[0088] Step b: Sorting of leaching residue (unwashed) Take 300g of the leaching residue obtained in step a, do not wash it, and directly mix it with 300g of water to prepare a slurry, which is then poured into a flotation machine. Subsequent desulfurization flotation and titanium flotation operations are performed exactly the same as in Example 1 (titanium collector dosage 450g / t leaching residue).

[0089] The final titanium concentrate had a titanium dioxide content of only 27.8%, and the titanium recovery rate in this stage of titanium flotation was as low as 50.4%. This contrasts sharply with Example 1 (after washing, the titanium concentrate grade was 37.8%, and the recovery rate was 90.1%). Due to the excessively low flotation recovery rate, which did not meet expectations, subsequent electrostatic separation experiments were discontinued. This comparative example demonstrates that the leaching residue must be washed before flotation to remove soluble impurity ions; otherwise, the flotation environment will be severely damaged, leading to poor collector selectivity and low recovery rate, thus proving the necessity of the washing operation in step b of this invention.

[0090] Comparative Example 3 (used to illustrate that in the electrostatic scavenging stage, if the dynamic adjustment based on the grade of the roughing tailings is not followed as described in this invention) The strategy of adjusting parameters will result in the final product failing to meet quality standards. Step a, acid leaching treatment Take 500g of raw material and leach it with nitric acid at 50℃ for 50 minutes. After solid-liquid separation, qualified leachate and leach residue are obtained. The particle size distribution of the leach residue is shown in Table 9. Table 9

[0091] A comparison of Table 9 and Table 3 shows that the content of -0.01mm particles decreased to 2.2%, and the titanium leaching rate was 26.2%.

[0092] Step b: Leachate sorting Take the leaching residue for washing (endpoint: Ca) 2+ The concentration of Mg is 0.09 g / L. 2+ <0.13g / L, pH=1.7), after slurry conditioning, desulfurization and titanium flotation were carried out (collector dosage 450g / t). Qualified titanium rough concentrate was obtained, with a titanium dioxide content of 37.5%, and the titanium recovery rate of the titanium flotation operation was 90.4%.

[0093] Step c, electrostatic purification (due to improper parameter adjustment) After drying, the titanium rough concentrate was subjected to electrostatic separation. The roughing conditions were set to 23 kV and 120 r / min, resulting in a titanium dioxide content of 6.4% in the roughing tailings. According to the strategy outlined in the claims of this invention, when the roughing tailings grade is less than 10%, the scavenging intensity should be appropriately reduced (adjusted to 85-95% of the roughing conditions) to ensure the concentrate grade. However, in this comparative example, the voltage was increased to 25 kV (approximately 109% of the roughing voltage, while the rotation speed remained constant) during scavenging. After merging the concentrates, the final titanium concentrate had a titanium dioxide content of only 45.1%, failing to meet the acceptable standard of 46.5% (despite an operating recovery rate of 90.1%).

[0094] This comparative example demonstrates that when the grade of the roughing tailings is already low, blindly increasing the scavenging electric field intensity will lead to more gangue minerals being carried into the concentrate, thus impairing the quality of the final product. This, conversely, confirms that the present invention dynamically adjusts the scavenging voltage and rotation speed according to the titanium dioxide content in the roughing tailings, which is beneficial for obtaining high-grade qualified titanium concentrate while ensuring high recovery rates.

[0095] 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. The functions, steps, and / or actions of the methods according to the disclosed embodiments described herein do not need to be performed in any particular order. Furthermore, 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.

[0096] It should be understood that, as used herein, the singular form “a” is intended to include the plural form as well, unless the context clearly supports an exception. It should also be understood that, as used herein, “and / or” refers to any and all possible combinations of one or more of the associated listed items.

[0097] The embodiment numbers disclosed in the above embodiments of the present invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0098] 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 improving the titanium recovery rate of vanadium-titanium magnetite, characterized in that, include: Step a: Acid leaching is performed on the vanadium-titanium magnetite sample, and after solid-liquid separation, leaching residue and titanium-containing leachate are obtained; Step b: After washing the leaching residue, adjust the slurry and perform desulfurization flotation and titanium flotation with only the addition of collector to obtain titanium rough concentrate. Then, dry the titanium rough concentrate and electrostatically separate it to obtain titanium concentrate product. Step c: Heat the titanium-containing leachate to carry out a titanium precipitation reaction, so that the titanium in it precipitates and the evaporated acid is recovered. After solid-liquid separation, titanium dioxide product is obtained.

2. The method for improving titanium recovery rate in vanadium-titanium magnetite according to claim 1, characterized in that, Step a includes: The vanadium-titanium magnetite sample was mixed with the acid solution and stirred at a speed of 300-400 r / min for 0.5-1.0 hours at a temperature of 50-70℃. The acid solution is hydrochloric acid or nitric acid solution, and the amount of acid solution added is determined based on a hydrogen ion concentration of 3-5 mol / L.

3. The method for improving titanium recovery rate in vanadium-titanium magnetite according to claim 1, characterized in that, Step b includes: The leaching residue is washed until the calcium ion concentration in the washing solution is below 0.1 g / L, the magnesium ion concentration is below 0.2 g / L, and the pH value reaches 1.5-2; The washed leaching residue is mixed with water to prepare a slurry with a mass concentration of 30-40%.

4. The method for improving titanium recovery rate in vanadium-titanium magnetite according to claim 3, characterized in that, Step b further includes: Add 400-500 g / t of titanium collector to the desulfurization flotation tailings for flotation.

5. The method for improving titanium recovery rate in vanadium-titanium magnetite according to claim 1, characterized in that, The electrical separation in step b includes: The dried titanium rough concentrate is subjected to one roughing and one scavenging process in sequence.

6. The method for improving titanium recovery rate in vanadium-titanium magnetite according to claim 5, characterized in that, The coarse selection includes: The dried titanium concentrate was roughed under the conditions of 20~25kV voltage and 100~130r / min drum rotation speed.

7. The method for improving titanium recovery rate in vanadium-titanium magnetite according to claim 5, characterized in that, The scanning includes: Detecting the titanium dioxide content in roughing tailings; If the titanium dioxide content is greater than 10%, the sweeping should be carried out at 110-120% of the coarse selection voltage and rotation speed; If the titanium dioxide content is no more than 10%, the sweeping should be carried out at 85-95% of the coarse selection voltage and rotation speed.

8. The method for improving titanium recovery rate in vanadium-titanium magnetite according to claim 7, characterized in that, Step c includes: The titanium-containing leachate is heated to 90-110°C to carry out the titanium precipitation reaction.

9. The method for improving titanium recovery rate in vanadium-titanium magnetite according to claim 7, characterized in that, Step c further includes: After solid-liquid separation, the separated titanium mother liquor is cooled and crystallized to obtain a mixed salt product.

10. The method for improving titanium recovery rate in vanadium-titanium magnetite according to claim 7, characterized in that, Step c further includes: The evaporated acid is returned to step a for acid leaching treatment.

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