Method for comprehensively treating schreyerite

Abstract

The invention belongs to the technical field of comprehensive utilization of metallic minerals, and particularly relates to a comprehensive treatment method for schreyerite. The treatment method comprises the following steps that sulfuric acid and an oxidizing agent are added into schreyerite, oxidation leaching and solid-liquid separation are conducted, and titanium-containing oxidation leaching residues and oxidation leaching filtrate are obtained; taking the oxidation leaching filtrate, adding schreyerite, carrying out a neutralization reaction, and carrying out solid-liquid separation to obtain neutralization reaction slag and a neutralization reaction filtrate; returning the neutralization reaction slag to participate in oxidation leaching; taking the neutralization reaction filtrate, condensing and crystallizing, and carrying out solid-liquid separation to obtain condensed mother liquor and ferric sulfate crystals; the vanadium element in the condensation mother liquor is extracted and separated, a vanadium-containing solution and raffinate are obtained, and the raffinate is returned to participate in oxidation leaching; according to the treatment method, vanadium, titanium and iron in the schreyerite can be recycled at the same time, valuable resources are effectively utilized, the acid consumption is small, materials can be internally recycled, the process is short, energy consumption is low, operation is easy and convenient, environment friendliness is achieved, and the economic and social benefits of the schreyerite can be improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of comprehensive utilization of metal minerals, and particularly relates to a method for comprehensive treatment of vanadium-titanium ore. Background Art

[0002] Vanadium, as an important microalloying element, is widely used in fields such as metallurgy, chemical engineering, and aerospace. It can significantly improve the strength, toughness, ductility, etc. of steel, and can provide important support for the preparation of special steel. Vanadium-titanium ore is a complex ore closely symbiotic with magnetite (Fe 3 O 4 ), ilmenorutile (2FeO·TiO 2 ), magnesia-alumina spinel (MgO·Al 2 O 3 ), and ilmenite (FeO·TiO 2 ). It is a multi-element symbiotic ore mainly composed of vanadium, titanium, and iron elements, and associated with other useful elements such as cobalt, nickel, and chromium, and has high comprehensive utilization value.

[0003] At present, the traditional treatment methods for vanadium-titanium ore mainly include two categories: direct vanadium extraction (iron first and then vanadium) and indirect vanadium extraction (vanadium first and then iron). The methods of direct vanadium extraction include sodium roasting - water leaching, calcification roasting - alkali leaching, and salt-free roasting - acid leaching, etc. However, the introduction of sodium salts will have an adverse impact on subsequent iron smelting; in the calcification roasting - alkali leaching process, the leaching effect of strong alkali is not ideal and the cost is too high; while the ammonia leaching has a lower leaching rate and a harsh operating environment; in the salt-free roasting - acid leaching process, too high roasting temperature will cause the volatilization of vanadium oxides, resulting in serious vanadium loss. When further extracting vanadium from low-grade vanadium extraction tailings, high-efficiency vanadium leaching can be achieved by reducing the pH, but the obtained leaching solution has a low vanadium concentration and a high impurity content. And because after the vanadium-containing material is roasted, vanadium exists in the form of pentavalent vanadium. In the case of a low pH and a high pentavalent vanadium concentration in the leaching solution, the solution system is unstable, and vanadium is prone to hydrolysis and precipitation, resulting in loss. Recycling vanadium from low-concentration vanadium-containing solutions can be classified into ion exchange method, extraction method, evaporation concentration method, etc. Through comprehensive comparison, these methods all have the problems of high cost and certain environmental protection risks. The typical method of indirect vanadium extraction is the blast furnace - converter process for vanadium extraction. However, when smelting vanadium-titanium ore in a blast furnace, there are problems such as a large system, a long and complex process, high energy consumption, high cost, a large amount of atmospheric pollutant emissions, and serious environmental pollution. Under the blast furnace smelting conditions, the viscosities of the slag and molten iron are large and the fluidity is poor, which makes the smelting difficult and even unable to meet the smelting requirements. At the same time, the recovery of titanium resources is poor, and a large amount of final slag is discarded or landfilled, causing serious pollution to the surrounding environment (especially the groundwater system); while the existing non-blast furnace smelting of vanadium-titanium ore resources has problems such as a small single-unit production scale, low titanium slag grade, and ineffective utilization of titanium resources. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the defects in the prior art, such as low vanadium recovery rate, ineffective recovery of titanium, high cost, and serious environmental pollution when treating vanadium-titanium ore, so as to provide a method for comprehensive treatment of vanadium-titanium ore.

[0005] For this purpose, the present invention provides the following technical solutions.

[0006] The present invention provides a method for comprehensive treatment of vanadium-titanium ore, including the following steps:

[0007] S1: Add sulfuric acid and an oxidant to the vanadium-titanium ore for oxidative leaching, followed by solid-liquid separation to obtain a titanium-containing oxidative leaching residue and an oxidative leaching filtrate;

[0008] S2: Take the oxidative leaching filtrate, add vanadium-titanium ore, carry out a neutralization reaction, and perform solid-liquid separation to obtain a neutralization reaction residue and a neutralization reaction filtrate; the neutralization reaction residue returns to S1 to participate in the oxidative leaching;

[0009] S3: Take the neutralization reaction filtrate, carry out condensation crystallization, and perform solid-liquid separation to obtain a condensation mother liquor and ferric sulfate crystals;

[0010] S4: Extract the vanadium element from the condensation mother liquor, separate to obtain a vanadium-containing solution and a raffinate, and the raffinate returns to S1 to participate in the oxidative leaching.

[0011] Optionally, in S4, it further includes the step of measuring the vanadium concentration in the condensation mother liquor. When the vanadium concentration < 5 g / L, the condensation mother liquor returns to S1 to participate in the oxidative leaching; when the vanadium concentration ≥ 5 g / L, extract the vanadium element from the condensation mother liquor, separate to obtain a vanadium-containing solution and a raffinate, and the raffinate returns to S1 to participate in the oxidative leaching.

[0012] Optionally, in S1, during the oxidative leaching, the mass ratio of acid to ore is 1 - 2:1, and the mass ratio of liquid to solid is 3 - 8:1.

[0013] Optionally, in S1, add an oxidant until the leaching rate of vanadium in the vanadium-iron ore ≥ 90%.

[0014] Optionally, in S1, the temperature of the oxidative leaching is 85 - 98 °C, and the time is 4 - 10 h.

[0015] Optionally, in S2, the mass-volume ratio of the added vanadium-titanium ore to the oxidative leaching filtrate is 50 - 100 g / L.

[0016] Optionally, in S2, the temperature of the neutralization reaction is 70 - 80 °C, the time is 2 - 4 h, and the pH at the end of the neutralization reaction is 1.3 - 1.5.

[0017] Optionally, in S3, the temperature of the condensation crystallization is 2 - 7 °C.

[0018] Optionally, in S4, the volume ratio of the extractant used in the extraction step to the condensed mother liquor is 1:12 to 20. Typically and non-limitingly, a multi-stage extraction method is adopted, such as five-stage extraction.

[0019] Optionally, it further includes a step of removing impurities from the vanadium-containing solution; optionally, the operation of removing impurities includes performing an electrochemical reduction reaction to obtain a vanadium-containing electrolyte solution and impurities. Using the electrochemical reduction reaction does not require additional addition of a reducing agent.

[0020] Optionally, the voltage of the electrochemical reduction reaction is 0.6 to 2 V, the temperature is 70 to 90 °C, and the time is 0.5 to 8 h.

[0021] Optionally, the concentration of the sulfuric acid is 85 wt% to 98 wt%.

[0022] Optionally, the oxidant includes at least one of SO 2 、H 2 O 2 ; optionally, the H 2 O 2 is added in the form of a solution, and its mass percentage is 20 to 30%.

[0023] Optionally, the extractant used in the extraction step includes at least one of a quaternary ammonium salt extractant and an amine extractant.

[0024] Optionally, the method of solid-liquid separation includes any one of filtration and centrifugation.

[0025] The beneficial effects of the present invention are as follows:

[0026] The method for comprehensive treatment of vanadium-titanium ore provided by the present invention comprises the following steps: S1: adding sulfuric acid and an oxidant to the vanadium-titanium ore for oxidative leaching, followed by solid-liquid separation to obtain titanium-containing oxidative leaching residue and oxidative leaching filtrate; S2: taking the oxidative leaching filtrate, adding vanadium-titanium ore for neutralization reaction, followed by solid-liquid separation to obtain neutralization reaction residue and neutralization reaction filtrate; the neutralization reaction residue is returned to S1 to participate in oxidative leaching; S3: taking the neutralization reaction filtrate, performing condensation crystallization and solid-liquid separation to obtain condensate mother liquor and ferric sulfate crystals; S4: extracting the vanadium element from the condensate mother liquor, followed by separation to obtain a vanadium-containing solution and a raffinate, and the raffinate is returned to S1 to participate in oxidative leaching. This treatment method can simultaneously recover vanadium, titanium, and iron in the vanadium-titanium ore, enabling effective utilization of valuable resources. The acid consumption is low, and all materials are recycled internally. The process is short, the reaction is carried out under normal pressure throughout, the energy consumption is low, the operation is simple, and there is no hazardous waste discharge, which is environmentally friendly and can enhance the economic and social benefits of the vanadium-titanium ore. In this treatment method, vanadium-titanium ore is used in the neutralization reaction in S2, and the neutralization reaction residue obtained after the reaction is returned to S1 to participate in oxidative leaching, so that no additional external neutralizing reagent needs to be added in this treatment method, achieving full use of raw materials and reducing costs. In the whole treatment method, the only residue produced is the titanium-containing oxidative leaching residue obtained in S1, and this residue can be used for further extraction of metallic titanium, reducing waste. The raffinate produced in S4 is returned to S1 to participate in oxidative leaching, realizing the recycling of liquid resources and also reducing the waste of the remaining vanadium element. The prepared vanadium-containing solution can be used to prepare vanadium-containing materials such as vanadium pentoxide, ferrovanadium, and vanadium alloy; the ferric sulfate crystals can be used as a mordant and a coagulant for industrial wastewater, and also as an astringent and hemostatic agent in medicine.

[0027] In the method for comprehensive treatment of vanadium-titanium ore provided by the present invention, in S4, it further includes the step of measuring the concentration of vanadium in the condensate mother liquor. When the concentration of vanadium < 5 g / L, the condensate mother liquor is returned to S1 to participate in oxidative leaching; when the concentration of vanadium ≥ 5 g / L, the vanadium element in the condensate mother liquor is extracted, followed by separation to obtain a vanadium-containing solution and a raffinate, and the raffinate is returned to S1 to participate in oxidative leaching. Enriching the vanadium in the condensate mother liquor to a certain concentration before extraction saves the consumption of the extractant and the extraction time.

[0028] The method for comprehensive treatment of vanadium-titanium ore provided by the present invention further includes the step of purifying the vanadium-containing solution; optionally, the purification operation includes performing an electrochemical reduction reaction to obtain a vanadium-containing electrolyte solution and impurities. The vanadium-containing electrolyte solution obtained after impurity removal by electrochemical reduction reaction has high vanadium purity and low impurity content, and can be formulated and applied to a vanadium redox flow battery after preparation. Description of the Drawings

[0029] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0030] Figure 1 It is a process flow schematic diagram of the method for comprehensive treatment of vanadium-titanium ore of the present invention. Specific embodiments

[0031] The following embodiments are provided to better further understand the present invention. They are not limited to the best embodiments, and do not limit the content and protection scope of the present invention. Any product identical or similar to the present invention obtained by anyone under the inspiration of the present invention or by combining the features of the present invention with those of other prior arts falls within the protection scope of the present invention.

[0032] For those not specifying specific experimental steps or conditions in the embodiments, the operations or conditions of the conventional experimental steps described in the literature in this field can be followed. For reagents or instruments not indicating the manufacturer, they are all conventional reagent products that can be obtained through commercial purchase.

[0033] Experimental drugs

[0034] Vanadium-titanium ore: V (0.83 wt.%), Ti (7.83 wt.%), Fe (54.05 wt.%).

[0035] Example 1

[0036] This example provides a method for comprehensive treatment of vanadium-titanium ore, and its process flow schematic diagram is as Figure 1 shown, and specifically includes the following steps:

[0037] (1) Add 98 wt% concentrated sulfuric acid and an oxidant (25 wt% hydrogen peroxide) to the vanadium-titanium ore. First, control the acid-ore mass ratio at 1.2:1, and then adjust the liquid-solid mass ratio to 4:1. Oxidatively leach at 98 °C for 6 h, and filter to obtain a titanium-containing oxidative leaching residue and an oxidative leaching filtrate. Among them, the oxidant is added dropwise, and the leaching rate of V at the end point is 93.4%.

[0038] (2) Take the oxidative leaching filtrate obtained in (1), add vanadium-titanium ore at a mass-volume ratio of 60 g / L, carry out a neutralization reaction at 75 °C for 3 h, and the pH at the end point of the reaction is 1.4. Filter to obtain a neutralization reaction residue and a neutralization reaction filtrate. Return the neutralization reaction residue to step (1) to participate in the oxidative leaching.

[0039] (3) Take the neutralization reaction filtrate obtained in (2), carry out condensation crystallization at 5°C, and filter to obtain ferric sulfate crystals and condensate mother liquor.

[0040] (4) Use an inductively coupled plasma spectrometer (ICP) to measure and calculate the concentration of vanadium in the condensate mother liquor. When the vanadium concentration < 5 g / L, return the condensate mother liquor to (1) to participate in oxidative leaching; when the vanadium concentration ≥ 5 g / L, use the amine extractant N235 to extract vanadium from the condensate mother liquor. Carry out 5-stage extraction, and the volume ratio of the extractant used to the condensate mother liquor is 1:15. Separate to obtain a vanadium-containing solution and a raffinate, and return the raffinate to (1) to participate in oxidative leaching.

[0041] (5) Carry out an electrochemical reduction reaction on the vanadium-containing solution for 2 h under the conditions of a voltage of 0.8 V and a temperature of 80°C to obtain a vanadium-containing electrolyte and impurities.

[0042] The titanium content in the titanium-containing oxidative leaching residue obtained in step (1) is determined by ICP to be 21 wt.% after enrichment, and it can be sent for smelting to extract metallic titanium.

[0043] In the vanadium-containing electrolyte obtained in step (5), after ICP measurement, the vanadium concentration is 76 g / L and the Fe concentration is 48 mg / L; the vanadium purity is high and can be applied to a vanadium redox flow battery after formulation.

[0044] This method only obtains products through two processes of hydrometallurgical leaching and impurity removal, without fire roasting, which can significantly shorten the process flow and reduce energy consumption. The recovery rate of V is 94%, the recovery rate of Ti is 72%, and the recovery rate of Fe is 85%. The formula for the element recovery rate is as follows: Element recovery rate = (element content in all liquid-phase products + element content in all solid-phase products) / element content in the original ore × 100%.

[0045] In the following examples and comparative examples, all the test methods and calculation methods are the same as those in Example 1 and will not be given again.

[0046] Example 2

[0047] This example provides a method for comprehensive treatment of vanadium-titanium ore, and the schematic diagram of its process flow is as Figure 1 shown, and specifically includes the following steps:

[0048] (1) Add 85 wt% concentrated sulfuric acid and an oxidant (SO 2 ) to the vanadium-titanium ore. First, control the mass ratio of acid to ore to be 2:1, and then adjust the mass ratio of liquid to solid to be 6:1. Carry out oxidative leaching at 85°C for 8 h, and filter to obtain a titanium-containing oxidative leaching residue and an oxidative leaching filtrate. Among them, the oxidant is added in the form of a coiled pipe at a flow rate of 200 mL / min to pass SO 2 gas into the pulp, and the leaching rate of V at the end point is 94.3%.

[0049] (2) Take the oxidized leaching filtrate obtained in (1), add vanadium-titanium ore at a mass-volume ratio of 100 g / L, carry out a neutralization reaction at 80 °C for 4 h, with the pH at the end point of the reaction being 1.5, filter to obtain a neutralization reaction residue and a neutralization reaction filtrate. Return the neutralization reaction residue to step (1) to participate in the oxidized leaching.

[0050] (3) Take the neutralization reaction filtrate obtained in (2), carry out condensation crystallization at 7 °C, filter to obtain ferric sulfate crystals and a condensation mother liquor.

[0051] (4) Measure the concentration of vanadium in the condensation mother liquor. When the concentration of vanadium < 5 g / L, return the condensation mother liquor to (1) to participate in the oxidized leaching; when the concentration of vanadium ≥ 5 g / L, extract vanadium from the condensation mother liquor using a quaternary ammonium salt extractant N263, carry out 5-stage extraction, with the volume ratio of the extractant used to the condensation mother liquor being 1:20, separate to obtain a vanadium-containing solution and a raffinate, and return the raffinate to (1) to participate in the oxidized leaching.

[0052] (5) Carry out an electrochemical reduction reaction on the vanadium-containing solution at a voltage of 1.5 V and a temperature of 90 °C for 1 h to obtain a vanadium-containing electrolyte solution and impurities.

[0053] The titanium content in the titanium-containing oxidized leaching residue obtained in step (1) is 24 wt.%, which can be sent for smelting to extract metallic titanium.

[0054] In the vanadium-containing electrolyte solution obtained in step (5), the vanadium concentration is 102 g / L and the Fe content is 42 mg / L; the vanadium purity is high and can be applied to a vanadium redox flow battery after formulation.

[0055] This method obtains products only through two processes of wet leaching and impurity removal, without fire roasting, which can significantly shorten the process flow and reduce energy consumption. The recovery rate of V is 92%, the recovery rate of Ti is 75%, and the recovery rate of Fe is 84%.

[0056] Example 3

[0057] This example provides a method for comprehensive treatment of vanadium-titanium ore, and its process flow schematic diagram is as Figure 1 shown, specifically including the following steps:

[0058] (1) Add 90 wt% concentrated sulfuric acid and an oxidant (30 wt% hydrogen peroxide and SO 2 ) to the vanadium-titanium ore. First, control the acid-ore mass ratio at 1:1, and then adjust the liquid-solid mass ratio at 3:1. Carry out oxidized leaching at 95 °C for 4 h, filter to obtain a titanium-containing oxidized leaching residue and an oxidized leaching filtrate. Among them, the addition method of the oxidant is to dropwise add hydrogen peroxide and pass SO 2 gas into the pulp at a flow rate of 200 mL / min. The leaching rate of V at the end point is 97.9%.

[0059] (2) Take the oxidized leaching filtrate obtained in (1), add vanadium-titanium ore at a mass-volume ratio of 50 g / L, carry out a neutralization reaction at 70 °C for 2 h, with the pH at the end point of the reaction being 1.3, filter to obtain a neutralization reaction residue and a neutralization reaction filtrate. Return the neutralization reaction residue to step (1) to participate in the oxidized leaching.

[0060] (3) Take the neutralization reaction filtrate obtained in (2), carry out condensation crystallization at 7 °C, filter to obtain ferric sulfate crystals and a condensation mother liquor.

[0061] (4) Measure the concentration of vanadium in the condensation mother liquor. When the vanadium concentration < 5 g / L, return the condensation mother liquor to (1) to participate in the oxidized leaching; when the vanadium concentration ≥ 5 g / L, extract vanadium from the condensation mother liquor using the amine extractant N1923, carry out 5-stage extraction, with the volume ratio of the extractant used to the condensation mother liquor being 1:18, separate to obtain a vanadium-containing solution and a raffinate, and return the raffinate to (1) to participate in the oxidized leaching.

[0062] (5) Carry out an electrochemical reduction reaction on the vanadium-containing solution under the conditions of a voltage of 0.6 V and a temperature of 70 °C for 0.5 h to obtain a vanadium-containing electrolyte solution and impurities.

[0063] The titanium content in the titanium-containing oxidized leaching residue obtained in step (1) is 23 wt.%, which can be sent for smelting to extract metallic titanium.

[0064] In the vanadium-containing electrolyte solution obtained in step (5), the vanadium concentration is 93 g / L and the Fe concentration is 38 mg / L; the vanadium purity is high and can be applied to a vanadium redox flow battery after formulation.

[0065] This method obtains products only through two processes of wet leaching and impurity removal, without fire roasting, which can significantly shorten the process flow and reduce energy consumption. The recovery rate of V is 96%, the recovery rate of Ti is 76%, and the recovery rate of Fe is 82%.

[0066] Example 4

[0067] This example provides a method for comprehensive treatment of vanadium-titanium ore, and its process flow schematic diagram is as Figure 1 shown, specifically including the following steps:

[0068] (1) Add 98 wt% concentrated sulfuric acid and an oxidant (SO 2 ) to the vanadium-titanium ore. First, control the acid-ore mass ratio to 1.5:1, and then add water to adjust the liquid-solid mass ratio to 8:1. Carry out oxidized leaching at 90 °C for 10 h, filter to obtain a titanium-containing oxidized leaching residue and an oxidized leaching filtrate. Among them, the oxidant is added in the form of a coil at a flow rate of 200 mL / min to pass SO 2 gas into the pulp, and the leaching rate of V at the end point is 92.4%.

[0069] (2) Take the oxidized leaching filtrate obtained in (1), add vanadium-titanium ore at a mass-volume ratio of 80 g / L, carry out a neutralization reaction at 75 °C for 3 h, with the pH at the end point of the reaction being 1.4, filter to obtain a neutralization reaction residue and a neutralization reaction filtrate. Return the neutralization reaction residue to step (1) to participate in the oxidized leaching.

[0070] (3) Take the neutralization reaction filtrate obtained in (2), carry out condensation crystallization at 2 °C, filter to obtain ferric sulfate crystals and a condensation mother liquor.

[0071] (4) Measure the concentration of vanadium in the condensation mother liquor. When the concentration of vanadium < 5 g / L, return the condensation mother liquor to (1) to participate in the oxidized leaching; when the concentration of vanadium ≥ 5 g / L, extract vanadium in the condensation mother liquor using a combination of quaternary ammonium salt extractant N263 and amine extractant N235 (volume ratio 1:1), carry out 5-stage extraction, with the volume ratio of the extractant used to the condensation mother liquor being 1:15, separate to obtain a vanadium-containing solution and a raffinate, and return the raffinate to (1) to participate in the oxidized leaching.

[0072] (5) Carry out an electrochemical reduction reaction on the vanadium-containing solution for 8 h under the conditions of a voltage of 2 V and a temperature of 75 °C to obtain a vanadium-containing electrolyte solution and impurities.

[0073] The titanium content in the titanium-containing oxidized leaching residue obtained in step (1) is 22 wt.%, which can be sent for smelting to extract metallic titanium.

[0074] In the vanadium-containing electrolyte solution obtained in step (5), the vanadium concentration is 78 g / L and the Fe concentration is 41 mg / L; the vanadium purity is high and can be applied to a vanadium redox flow battery after formulation.

[0075] This method obtains products only through two steps of wet leaching and impurity removal processes, without fire roasting, which can significantly shorten the process flow and reduce energy consumption. The recovery rate of V is 91%, the recovery rate of Ti is 73%, and the recovery rate of Fe is 81%.

[0076] Comparative Example 1

[0077] This example provides a method for comprehensive treatment of vanadium-titanium ore, specifically including the following steps:

[0078] (1) First, roast the vanadium-titanium ore at 500 °C for 3 h, and then add 98 wt% concentrated sulfuric acid thereto. First, control the acid-ore mass ratio at 1.5:1, and then adjust the liquid-solid mass ratio at 8:1, carry out leaching at 90 °C for 10 h, filter to obtain a titanium-containing leaching residue and a leaching filtrate.

[0079] (2) Take the leaching filtrate obtained in (1), add vanadium-titanium ore at a mass-volume ratio of 80 g / L, carry out a neutralization reaction at 75 °C for 3 h, with the pH at the end point of the reaction being 1.4, filter to obtain a neutralization reaction residue and a neutralization reaction filtrate. Return the neutralization reaction residue to step (1) to participate in the oxidized leaching.

[0080] (3) Take the neutralization reaction filtrate obtained in (2), carry out condensation crystallization at 2 °C, and filter to obtain ferric sulfate crystals and condensation mother liquor.

[0081] (4) Measure the concentration of vanadium in the condensation mother liquor. When the vanadium concentration < 5 g / L, return the condensation mother liquor to (1) for leaching; when the vanadium concentration ≥ 5 g / L, extract vanadium from the condensation mother liquor using the amine extractant N235. Perform 5-stage extraction, and the volume ratio of the extractant used to the condensation mother liquor is 1:15. Separate to obtain a vanadium-containing solution and a raffinate, and return the raffinate to (1) for leaching.

[0082] (5) Carry out an electrochemical reduction reaction on the vanadium-containing solution for 8 h under the conditions of a voltage of 2 V and a temperature of 75 °C to obtain a vanadium-containing electrolyte solution and impurities.

[0083] The vanadium content in the titanium-containing oxidative leaching residue obtained in step (1) is 0.35 wt.%, and the titanium content is 13 wt.%, and it cannot be sent for smelting to extract metallic titanium.

[0084] In the vanadium-containing electrolyte solution obtained in step (5), the vanadium concentration is 77 g / L and the Fe concentration is 47 mg / L; the vanadium purity is high and can be applied to a vanadium redox flow battery after formulation.

[0085] This method obtains products through three steps of roasting, hydrometallurgical leaching, and finally impurity removal. Fire roasting is required, so the process flow is long, energy consumption increases, and the element recovery rate in the slag is low. The recovery rate of V is 75%, the recovery rate of Ti is 46%, and the recovery rate of Fe is 63%.

[0086] Comparative Example 2

[0087] This example provides a method for comprehensive treatment of vanadium-titanium ore, which specifically includes the following steps:

[0088] (1) Add 98 wt% concentrated sulfuric acid to the vanadium-titanium ore. First, control the acid-ore mass ratio at 1.2:1, and then adjust the liquid-solid mass ratio to 4:1. Leach at 98 °C for 6 h, and filter to obtain a titanium-containing leaching residue and a filtrate.

[0089] (2) Then take the leaching residue and add 98 wt% concentrated sulfuric acid for secondary leaching. First, control the acid-ore mass ratio at 1.2:1, and then adjust the liquid-solid mass ratio to 4:1. Leach at 98 °C for 3 h, and filter to obtain a secondary leaching residue and a secondary filtrate.

[0090] (3) Take the secondary filtrate obtained in (2), carry out condensation crystallization at 2 °C, and filter to obtain ferric sulfate crystals and condensation mother liquor.

[0091] (4) Measure the concentration of vanadium in the condensed mother liquor. When the vanadium concentration < 5 g / L, return the condensed mother liquor to (1) for leaching; when the vanadium concentration ≥ 5 g / L, extract vanadium from the condensed mother liquor using the amine extractant N235. Perform 5-stage extraction, with the volume ratio of the extractant to the condensed mother liquor being 1:15. Separate to obtain a vanadium-containing solution and a raffinate, and return the raffinate to (1) for leaching.

[0092] (5) Electrochemically reduce the vanadium-containing solution under the conditions of a voltage of 2 V and a temperature of 75 °C for 8 h to obtain a vanadium-containing electrolyte and impurities.

[0093] The titanium content in the titanium-containing oxidized leaching residue obtained in step (1) is 17 wt.%, and it cannot be sent for smelting to extract metallic titanium.

[0094] In the vanadium-containing electrolyte obtained in step (5), the vanadium concentration is 68 g / L and the Fe concentration is 129 mg / L; the vanadium purity is poor and it cannot be applied to a vanadium redox flow battery.

[0095] This method obtains products through two-stage leaching and two-step impurity removal processes, but the acid consumption doubles, and the acidity of the obtained filtrate is high, which has a greater impact on the subsequent condensation and extraction processes, has strong corrosion on equipment, increases costs, and has a low element recovery rate in the slag. The recovery rate of V is 86%, the recovery rate of Ti is 59%, and the recovery rate of Fe is 74%.

[0096] Obviously, the above embodiments are merely examples given for clear illustration and are not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation manners here. And the obvious changes or modifications derived therefrom are still within the protection scope of this invention.

Claims

1. A method for comprehensive treatment of vanadium-titanium ore, characterized in that: The steps include: S1: adding sulfuric acid and an oxidant to the vanadium-titanium ore, oxidative leaching, solid-liquid separation, and obtaining titanium-containing oxidative leaching residue and oxidative leaching filtrate; S2: taking the oxidation leaching filtrate, adding vanadium-titanium ore, neutralizing, and separating the solid and liquid to obtain neutralization reaction residue and neutralization reaction filtrate; the neutralization reaction residue is returned to S1 to participate in oxidation leaching; S3: taking the neutralization reaction filtrate, condensing and crystallizing, and separating the solid and liquid to obtain a condensed mother liquor and ferric sulfate crystals; S4: extracting the vanadium element in the condensed mother liquor, separating and obtaining a vanadium-containing solution and a raffinate, and the raffinate is returned to S1 to participate in oxidation leaching.

2. The method for comprehensive treatment of vanadium-titanium ore according to claim 1, characterized in that: The S4 also includes a step of determining the concentration of vanadium in the condensed mother liquor. When the concentration of vanadium is less than 5 g / L, the condensed mother liquor is returned to S1 to participate in oxidative leaching. When the concentration of vanadium is greater than or equal to 5 g / L, the vanadium element in the condensed mother liquor is extracted and separated to obtain a vanadium-containing solution and a raffinate. The raffinate is returned to S1 to participate in oxidative leaching.

3. The method for comprehensive treatment of vanadium-titanium ore according to claim 1 or 2, characterized in that: In S1, the acid-ore mass ratio during oxidation leaching is 1-2:1, and the liquid-solid mass ratio is 3-8:1; and / or, in said S1, an oxidant is added to the vanadium leaching rate in the vanadium iron ore to be ≥ 90%; And / or, in S1, the oxidation leaching temperature is 85-98° C. and the time is 4-10 hours.

4. The method for comprehensive treatment of vanadium-titanium ore according to any one of claims 1 to 3, characterized in that: In S2, the mass volume ratio of the vanadium-titanium ore and the oxidation leaching filtrate is 50-100 g / L; And / or, in S2, the neutralization reaction temperature is 70-80° C., the time is 2-4 hours, and the pH at the end point of the neutralization reaction is 1.3-1.

5.

5. The method for comprehensive treatment of vanadium-titanium ore according to any one of claims 1 to 4, characterized in that: In S3, the temperature of condensation crystallization is 2-7°C.

6. The method for comprehensive treatment of vanadium-titanium ore according to any one of claims 1 to 5, characterized in that: In S4, the volume ratio of the extractant used in the extraction step to the condensed mother liquor is 1:12-20.

7. The method for comprehensive treatment of vanadium-titanium ore according to any one of claims 1 to 6, characterized in that: The method further comprises the step of removing impurities from the vanadium-containing solution; optionally, the operation of removing impurities comprises performing an electrochemical reduction reaction to obtain a vanadium-containing electrolyte and impurities.

8. The method for comprehensive treatment of vanadium-titanium ore according to claim 7, characterized in that: The voltage of the electrochemical reduction reaction is 0.6-2V, the temperature is 70-90°C, and the time is 0.5-8h.

9. The method for comprehensive treatment of vanadium-titanium ore according to any one of claims 1 to 8, characterized in that: The concentration of the sulfuric acid is 85 wt % to 98 wt %.

10. The method for comprehensive treatment of vanadium-titanium ore according to any one of claims 1 to 9, characterized in that: The oxidant includes at least one of SO2 and H2O2; optionally, the H2O2 is added in the form of a solution with a mass percentage of 20 to 30%; and / or, the extractant used in the extraction step comprises at least one of a quaternary ammonium salt extractant and an amine extractant; And / or, the solid-liquid separation method includes any one of filtration and centrifugation.

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