Preparation method for wet separation of iron, vanadium and titanium in vanadium titano-magnetite

Abstract

The invention discloses a preparation method for separating iron, vanadium and titanium in vanadium titano-magnetite by a wet method, belongs to the technical field of chemical metallurgy, and particularly adopts the technologies of hydrochloric acid ore dissolution, solid-liquid separation, iron powder reduction, freezing crystallization, extraction and the like to gradually separate and obtain titanium, iron and titanium products. By means of the method, the ore dissolving efficiency can be effectively improved, the technological process is shortened, traditional vanadium precipitation wastewater and treatment cost are avoided, titanium, iron and vanadium can be effectively separated and recycled, and value maximization of the South African vanadium titano-magnetite is effectively achieved.

Description

Technical Field

[0001] The invention relates to the technical field of chemical metallurgy, and in particular to a preparation method for wet separation of iron, vanadium and titanium in vanadium-titanium magnetite. Background Art

[0002] Vanadium-titanium magnetite is a low-grade multi-metallic mineral with great utilization value. It contains key elements such as iron, titanium, and vanadium, and is also associated with a variety of metal elements such as chromium, cobalt, nickel, copper, and gallium. Globally, South Africa's vanadium-titanium magnetite resources are particularly eye-catching. With its abundant reserves, it accounts for 31% of the world's total vanadium reserves, showing a unique advantage in resource reserves. At present, the processing of South African vanadium-titanium magnetite has many disadvantages in traditional processing methods. The processing process usually involves beneficiation and enrichment of the original ore to separate the vanadium-titanium magnetite concentrate, and then the concentrate enters the iron-making blast furnace process, focusing on the extraction of iron and vanadium elements. In this process, titanium is mostly treated as slag. Due to the close symbiosis of titanium and iron, coupled with the limitations of the existing process level, the high content of titanium in the ore cannot be effectively utilized, resulting in a huge waste of resources.

[0003] At present, the existing conventional technical means have two shortcomings. On the one hand, the comprehensive utilization rate of vanadium is greatly reduced, and a large amount of potential value has not been tapped; on the other hand, it has also produced many negative impacts on the environment. In the vanadium extraction process, a large amount of high-salt and high-ammonia nitrogen wastewater will be continuously produced, which is extremely difficult to treat. Furthermore, even if methods such as high-temperature oxidation / sodium treatment are used to extract vanadium, although vanadium can be extracted, the problems of vanadium extraction wastewater pollution and low titanium recovery rate cannot be avoided. Therefore, it is of great value and significance to develop a comprehensive extraction method that can simultaneously and efficiently separate and recover iron, vanadium and titanium. This not only helps to improve the utilization rate of resources, but also reduces environmental pollution and promotes the sustainable development of vanadium-titanium magnetite resources.

[0004] In view of this, the present invention is proposed. Summary of the invention

[0005] In order to achieve efficient separation of titanium, iron and vanadium from vanadium-titanium magnetite and maximize the value of mineral resources, the present invention proposes an efficient, energy-saving, green and environmentally friendly extraction and separation technology, which provides a new approach and method for the fine processing of vanadium-titanium magnetite. The key technology is to use efficient ore dissolution technology to obtain ferrovanadium acid solution and separate high-titanium slag, use iron powder to reduce to obtain vanadium-containing solution and separate ferrous chloride crystals, then extract and precipitate the vanadium-containing solution to prepare ammonium metavanadate.

[0006] The present invention is achieved in that:

[0007] The present invention provides a preparation method for wet separation of iron, vanadium and titanium in vanadium-titanium magnetite, the steps of which include: mixing hydrochloric acid and vanadium-titanium magnetite for reaction, then introducing hydrogen chloride gas into the system, ensuring that the temperature and pressure of the system are maintained at set values ​​during the reaction, cooling the reaction mixture after the reaction is completed, then adding an oxidant, performing solid-liquid separation after the oxidation reaction is completed, and obtaining high-titanium slag and a hydrochloric acid solution containing vanadium-iron ions;

[0008] A reducing agent is added to a hydrochloric acid solution containing vanadium iron ions for reduction, and after the reduction reaction is completed, the solution is frozen to precipitate ferrous chloride crystals, and then solid-liquid separation is performed to obtain ferrous chloride crystals and a vanadium-containing solution;

[0009] The vanadium-containing solution is subjected to multi-stage extraction using a vanadium extractant to obtain a vanadium-rich organic phase and an aqueous phase combined with extracts from each stage, and then the vanadium-enriched organic phase is added with a precipitant to prepare a vanadium precipitate, and finally ammonium metavanadate is obtained through post-treatment.

[0010] In some preferred embodiments, the mass ratio of the vanadium-titanium magnetite to the hydrochloric acid is 1:2-10.

[0011] In some preferred embodiments, the vanadium-titanium magnetite is vanadium-titanium magnetite from South Africa, and has a titanium dioxide content of 12-15%, an iron oxide content of 60-70%, and a vanadium pentoxide content of 1.0-1.4%.

[0012] In some preferred embodiments, the mass percentage concentration of the hydrochloric acid is 10%-30%.

[0013] In some preferred embodiments, the temperature setting value is 25-100° C., and the pressure setting value is 0.101 MPa-1.0 MPa.

[0014] In some preferred embodiments, the reducing agent is iron powder with a particle size of 80-200 mesh.

[0015] In some preferred embodiments, the precipitant is aqueous ammonia.

[0016] In some preferred embodiments, the titanium dioxide content of the high titanium slag is 68-75%, and the titanium recovery rate is 98-99%.

[0017] In some preferred embodiments, the ferrous chloride crystals are further oxidized and calcined to form an iron oxide product with a purity greater than 98% and an iron recovery rate of 95-99%.

[0018] In some preferred embodiments, the purity of the ammonium metavanadate is greater than 98%, and the recovery rate of vanadium is 85-90%.

[0019] The present invention has the following beneficial effects:

[0020] 1. The present invention adopts a hydrochloric acid acid dissolution wet method to effectively separate titanium, iron and vanadium from vanadium-titanium magnetite, thereby efficiently recovering titanium, iron and vanadium from vanadium-titanium magnetite.

[0021] 2. Avoid high-temperature oxidation and calcination processes, as well as the high-salt and high-ammonia nitrogen wastewater produced as a by-product in the vanadium extraction process of the existing vanadium precipitation industry, greatly reducing production costs and improving the application value of vanadium-titanium magnetite. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0023] Figure 1 This is the production flow chart of Example 1. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased commercially.

[0025] In order to achieve efficient separation of iron, vanadium and titanium from vanadium-titanium magnetite and maximize the value of mineral resources, the present invention provides a preparation method for wet separation of iron, vanadium and titanium from vanadium-titanium magnetite, the steps of which include: mixing hydrochloric acid and vanadium-titanium magnetite for reaction, then introducing hydrogen chloride gas into the system, ensuring that the temperature and pressure of the system are maintained at set values ​​during the reaction, cooling the reaction mixture after the reaction is completed, and then adding an oxidant, performing solid-liquid separation after the oxidation reaction is completed, and obtaining high-titanium slag and a hydrochloric acid solution containing vanadium-iron ions;

[0026] A reducing agent is added to a hydrochloric acid solution containing vanadium iron ions for reduction, and after the reduction reaction is completed, the solution is frozen to precipitate ferrous chloride crystals, and then solid-liquid separation is performed to obtain ferrous chloride crystals and a vanadium-containing solution;

[0027] The vanadium-containing solution is subjected to multi-stage extraction using a vanadium extractant to obtain a vanadium-rich organic phase and an aqueous phase combined with extracts from each stage, and then the vanadium-enriched organic phase is added with a precipitant to prepare a vanadium precipitate, and finally ammonium metavanadate is obtained through post-treatment.

[0028] In the embodiment of the present invention, the vanadium-titanium magnetite selected is the vanadium-titanium magnetite from South Africa, wherein the titanium dioxide content is 12%-15%, the iron oxide content is 60%-70%, and the vanadium pentoxide content is 1.0%-1.4%. Among them, the South African vanadium-titanium magnetite has a high content of titanium, vanadium and iron, which helps to reduce the extraction cost of the three metals, and the metal recovery rate of titanium, vanadium and iron of the South African vanadium-titanium magnetite can reach more than 90%, which improves the utilization rate of mineral resources. In addition, the transportation and cost of the South African vanadium-titanium magnetite are relatively low, which helps to reduce the overall production cost.

[0029] In order to improve the leaching efficiency of vanadium, hydrogen chloride gas is introduced into the mixed system of hydrochloric acid and vanadium-titanium magnetite to ensure that the pressure setting value during the reaction is 0.101MPa-1.0MPa and the setting temperature of the overall system is 25℃-100℃. This method can more effectively destroy the ore structure and increase the extractability of vanadium.

[0030] In some preferred embodiments, the reducing agent is iron powder with a particle size of 80-200 mesh.

[0031] Among them, the advantage of using iron powder to reduce the hydrochloric acid solution containing vanadium iron ions is that it can selectively reduce vanadium ions to a low-valent state, thereby improving the extraction efficiency of vanadium. At the same time, the reaction conditions are mild, and high temperature or high pressure is not required, which helps to reduce energy consumption and equipment requirements. As a cost-effective and environmentally friendly reducing agent, the use of iron powder can reduce production costs and reduce environmental impact, and the process is simple, easy to operate and control. In addition, iron powder reduction can also improve the recovery rate of vanadium, making full use of vanadium resources, and the byproduct iron oxide is relatively easy to handle and recycle, further enhancing the industrial application value of this method.

[0032] In some preferred embodiments, the precipitant is aqueous ammonia.

[0033] Among them, the selective vanadium precipitation function of ammonia water helps to improve the purity of the product, while avoiding the use of traditional chlorate vanadium oxidation and reducing the production of chlorine. Using ammonia water as a precipitant to prepare vanadium precipitation can improve the purity of the product, because ammonia water can effectively and selectively precipitate vanadium and reduce impurity co-precipitation. At the same time, ammonia water as a precipitant does not produce harmful by-products, is environmentally friendly, and has low cost and is easy to obtain. The precipitation process is simple to operate, easy to control, and the subsequent treatment is relatively simple. In addition, the ammonia precipitation method helps to improve the recovery rate of vanadium and make more efficient use of vanadium resources. These advantages together constitute the comprehensive benefits of using ammonia water as a precipitant.

[0034] In some preferred embodiments, the titanium dioxide content of the high titanium slag is 68-75%, and the titanium recovery rate is 98-99%.

[0035] In some preferred embodiments, the ferrous chloride crystals are oxidatively calcined to form an iron oxide product with a purity greater than 98% and an iron recovery rate of 95-99%.

[0036] In some preferred embodiments, the purity of the ammonium metavanadate is greater than 98%, and the recovery rate of vanadium is 85-90%.

[0037] Among them, after the vanadium precipitate is prepared, ammonium metavanadate is obtained through post-treatment, and the post-treatment steps include: mixing the vanadium precipitate with ammonia water, adjusting the pH value of the solution to the alkaline range, so that the vanadium is precipitated in the form of ammonium metavanadate; after the precipitation reaction is completed, the ammonium metavanadate precipitate is separated from the solution by solid-liquid separation technology; the obtained ammonium metavanadate precipitate needs to be washed to further remove residual impurities and ammonia water; finally, the ammonium metavanadate precipitate is dried for subsequent processing or use. The temperature and time need to be controlled during the drying process to avoid decomposition or loss of ammonium metavanadate.

[0038] The features and performance of the present invention are further described in detail below in conjunction with the embodiments.

[0039] Example 1

[0040] like Figure 1 As shown, this embodiment provides a method for effectively extracting vanadium from vanadium-titanium magnetite, which specifically includes the following steps:

[0041] (1) Take 500 g of vanadium-titanium magnetite, add 1500 g of 30% concentrated hydrochloric acid, stir, and continuously introduce hydrogen chloride gas into the system to maintain the acid value of the system unchanged and keep the pressure of the system at 0.1 MPa. After reacting for 10 hours, stop, cool to room temperature, filter by pressure, wash the residue until it is neutral, and collect high-titanium slag;

[0042] (2) the filtrate is placed in a reduction kettle, 75 g of iron powder is added, the reaction is continued under stirring for 1 hour, and then the ferrous chloride is precipitated by freezing, and the solid-liquid separation is performed to obtain ferrous chloride crystals and a vanadium-containing filtrate, and the ferrous chloride crystals are further oxidized and calcined to form an iron oxide product;

[0043] (3) The vanadium-containing filtrate enters the vanadium extractor, at 30°C, TBP / P204 / sulfonated no (wt) = 1:1:2 is used as the extractant, the oil phase and water phase ratio O / A = 4:1, after two-stage extraction, the oil phase is the vanadium extraction phase, and the water phase is an acidic solution to increase the acid value and return to the molten ore;

[0044] (4) The vanadium extraction phase directly enters the vanadium synthesis reactor, and a small amount of 20% ammonia aqueous solution is added to the system to prepare a vanadium precipitate. Finally, the vanadium precipitate is mixed with ammonia water, and the pH value of the solution is adjusted to an alkaline range to precipitate the vanadium in the form of ammonium metavanadate. After the precipitation, the ammonium metavanadate precipitate is separated from the solution by a solid-liquid separation technology, and the obtained ammonium metavanadate precipitate is washed and dried to obtain ammonium metavanadate.

[0045] The components of the South African vanadium-titanium magnetite and the obtained high-titanium slag used in Example 1 were subjected to XRF testing as shown in Table 1, the ferric chloride solution was further oxidized and calcined to form an iron oxide product, which was tested according to the national standard as shown in Table 2, and the ammonium metavanadate was tested according to the national standard as shown in Table 3.

[0046] Table 1. Composition of vanadium-titanium magnetite and high-titanium slag

[0047]

[0048] Note: “ / ” means not detected.

[0049] Table 2. Main composition of iron oxide

[0050]

[0051] Note: The ferrous chloride in Example 1 was further processed to prepare ferric oxide for testing and compared with the national standard; “ / ” means not detected.

[0052] Table 3. Main composition of ammonium metavanadate

[0053]

[0054] According to the results shown above, it can be seen from Table 1 that the titanium (TiO2) content in the high-titanium slag is significantly increased to 79.14%, while the iron (FeO) content is greatly reduced to 1.18%, which indicates that titanium is effectively enriched and iron is successfully removed, which is conducive to the further extraction and purification of vanadium. In addition, the content of magnesium (MgO) and manganese (MnO) in the high-titanium slag is reduced, while the content of silicon dioxide (SiO2) and aluminum oxide (Al2O3) is increased. This may be due to the relative stability of these components during the extraction process. Vanadium (V2O5) is not detected in the high-titanium slag, indicating that it has been separated from the ore and transferred to the filtrate. The analysis results of Table 2 show that the iron oxide product prepared in Example 1 has a high purity, wherein the content of Fe2O3 reaches 98.13%, meeting the national standard requirement of 98%. At the same time, the impurity content in the iron oxide, including MgO, Al2O3, SiO2, MnO, P2O5, Cl - 、SO4 2-, K2O and CaO are all lower than the national standard limit, which shows that through the process of this embodiment, high-purity iron oxide can be successfully extracted and prepared from the vanadium-containing filtrate, and the impurities are well controlled, meeting the standard of high-quality products. The analysis results of Table 3 show that the ammonium metavanadate product prepared in Example 1 has reached a high standard of purity, wherein the content of V2O5 is 98.2%, exceeding the national standard requirement of 98%. In addition, the ammonia solubility in ammonium metavanadate is qualified, and Cl - and SO4 2- The contents of are all lower than the limit of national standards, and the content of Fe also meets the standards. By precisely controlling the chemical reaction conditions and post-treatment steps, this method can successfully extract and prepare high-quality ammonium metavanadate from the vanadium extraction phase, providing high-quality raw materials for the further processing and application of vanadium.

[0055] In summary, this embodiment provides an efficient and environmentally friendly method for treating vanadium-titanium magnetite, which successfully achieves effective separation and purification of iron, titanium and vanadium through hydrochloric acid dissolution, solid-liquid separation, iron powder reduction, freezing crystallization, extraction and other technologies. The enrichment of titanium and the significant reduction of iron in high-titanium slag, the high purity of iron oxide products, and the high standard purity of ammonium metavanadate all prove the superiority of this process in resource recovery and product preparation. In addition, the method shows significant advantages in improving metal recovery, reducing production costs, reducing environmental pollution and realizing resource recycling, and provides a reliable, economical and environmentally friendly solution for the comprehensive utilization of vanadium-titanium magnetite and the industrial production of vanadium products.

[0056] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing iron, vanadium and titanium from vanadium-titanium magnetite by wet separation, characterized in that: The steps include: mixing hydrochloric acid and vanadium-titanium magnetite to react, then introducing hydrogen chloride gas into the system, ensuring that the temperature and pressure of the system are maintained at set values ​​during the reaction, cooling the reaction mixture after the reaction is completed, and then adding an oxidant, and performing solid-liquid separation after the oxidation reaction is completed to obtain high-titanium slag and a hydrochloric acid solution containing vanadium-iron ions; A reducing agent is added to a hydrochloric acid solution containing vanadium iron ions for reduction, and after the reduction reaction is completed, the solution is frozen to precipitate ferrous chloride crystals, and then solid-liquid separation is performed to obtain ferrous chloride crystals and a vanadium-containing solution; The vanadium-containing solution is subjected to multi-stage extraction using a vanadium extractant to obtain a vanadium-rich organic phase and an aqueous phase combined with extracts from each stage, and then the vanadium-enriched organic phase is added with a precipitant to prepare a vanadium precipitate, and finally ammonium metavanadate is obtained through post-treatment.

2. The method for preparing iron, vanadium and titanium by wet separation of vanadium-titanium magnetite according to claim 1, characterized in that: The mass ratio of the vanadium-titanium magnetite to the hydrochloric acid is 1:2-10.

3. The method for preparing iron, vanadium and titanium by wet separation of vanadium-titanium magnetite according to claim 1, characterized in that: The vanadium-titanium magnetite is from South Africa, and has a titanium dioxide content of 12-15%, an iron oxide content of 60-70%, and a vanadium pentoxide content of 1.0-1.4%.

4. The method for preparing iron, vanadium and titanium from vanadium-titanium magnetite by wet separation according to claim 1, characterized in that: The mass percentage concentration of the hydrochloric acid is 10%-30%.

5. The method for preparing iron, vanadium and titanium from vanadium-titanium magnetite by wet separation according to claim 1, characterized in that: The temperature setting value is 25-100° C., and the pressure setting value is 0.101 MPa-1.0 MPa.

6. The method for preparing iron, vanadium and titanium from vanadium-titanium magnetite by wet separation according to claim 1, characterized in that: The reducing agent is iron powder with a particle size of 80-200 meshes.

7. The method for preparing iron, vanadium and titanium from vanadium-titanium magnetite by wet separation according to claim 1, characterized in that: The precipitant is aqueous ammonia.

8. The method for preparing iron, vanadium and titanium from vanadium-titanium magnetite by wet separation according to claim 1, characterized in that: The titanium dioxide content of the high-titanium slag is 68-75%, and the titanium recovery rate is 98-99%.

9. The method for preparing iron, vanadium and titanium by wet separation of vanadium-titanium magnetite according to claim 1, characterized in that: The ferrous chloride crystals are oxidized and calcined to form an iron oxide product with a purity greater than 98% and an iron recovery rate of 95-99%.

10. The method for preparing iron, vanadium and titanium from vanadium-titanium magnetite by wet separation according to claim 1, characterized in that: The purity of the ammonium metavanadate is greater than 98%, and the recovery rate of vanadium is 85-90%.

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