A method for separating niobium and titanium from titanium-containing crude niobium concentrate through oxidative roasting and magnetic separation.

Abstract

This invention relates to a method for separating niobium and titanium through oxidative roasting and magnetic separation of titanium-containing crude niobium concentrate, belonging to the field of mineral processing and beneficiation. This invention involves oxidative roasting of titanium-containing crude niobium concentrate to reconstruct the minerals, causing a phase transition in the ilmenite and enhancing its magnetic properties. This alters the magnetic strength of the ilmenite and niobium minerals in the concentrate. The oxidative roasting product after mineral reconstruction is then cooled. The cooled oxidative roasting product undergoes a first-stage magnetic separation to obtain a first-stage magnetic product. This first-stage magnetic product is then subjected to a second-stage magnetic separation to obtain a titanium product. The non-magnetic product obtained from the first-stage magnetic separation is mixed with the non-magnetic product obtained from the second-stage magnetic separation to obtain niobium concentrate. This invention simplifies the process flow in separation and upgrading, and simultaneously obtains high-grade and high-recovery niobium concentrate and titanium product through the oxidative roasting-magnetic separation method.

Description

Technical Field

[0001] This invention belongs to the field of mineral processing technology, and specifically relates to a method for separating niobium and titanium by oxidative roasting and magnetic separation of titanium-containing crude niobium concentrate. Background Technology

[0002] Niobium, as a strategic mineral resource, plays a vital role in modern high-tech industries. Adding it to materials significantly enhances their strength, conductivity, and corrosion resistance, leading to its widespread application in various fields such as medicine, new materials, metallurgy, and advanced electronics.

[0003] my country's Bayan Obo mining area boasts abundant niobium resources, but due to its high degree of association with minerals such as ilmenite and their similar physicochemical properties, the crude niobium concentrate obtained by traditional flotation / magnetic separation processes is of low grade, often containing large amounts of ilmenite. This leads to increased niobium smelting costs and fails to meet the demands for high-grade niobium alloy production. Developing novel niobium-titanium separation technologies has become a key breakthrough in overcoming resource utilization bottlenecks, reducing import dependence, and promoting the development of the niobium industry chain.

[0004] To achieve effective separation of niobium and ilmenite, conventional separation processes utilize the differences in density, magnetism, and reaction to flotation reagents between niobium and ilmenite. However, due to the very similar physicochemical properties of niobium and ilmenite, conventional separation processes suffer from low efficiency. Therefore, these processes still limit the separation effect, failing to yield high-grade and high-recovery niobium concentrate and titanium products. Thus, simplifying the separation process, optimizing separation efficiency, and improving the sustainability of the entire mineral processing are of paramount practical significance and application value. Summary of the Invention

[0005] To address the shortcomings of the existing technology, the purpose of this invention is to provide a method for separating niobium and titanium by oxidative roasting and magnetic separation of titanium-containing crude niobium concentrate. This method simultaneously yields high-grade niobium concentrate and titanium products with high recovery rates through oxidative roasting and wet magnetic separation.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0007] The present invention provides a method for separating niobium and titanium by oxidative roasting and magnetic separation of titanium-containing crude niobium concentrate, comprising the following steps:

[0008] Titanium-containing crude niobium concentrate is reconstructed by oxidative roasting to cause a phase transformation in ilmenite, which enhances its magnetism. This changes the magnetic properties of ilmenite and niobite in the titanium-containing crude niobium concentrate. The oxidative roasting product after mineral reconstruction is then cooled.

[0009] The cooled oxidative roasting product undergoes a first-stage magnetic separation to obtain a first-stage magnetic product. This first-stage magnetic product is then subjected to a second-stage magnetic separation to obtain a titanium product. The non-magnetic product obtained from the first-stage magnetic separation is mixed with the non-magnetic product obtained from the second-stage magnetic separation to obtain niobium concentrate.

[0010] Preferably, the titanium-containing crude niobium concentrate is roasted in an oxidizing atmosphere at a temperature of 550℃~600℃ for 60min~120min.

[0011] Preferably, the oxidized roasted product is cooled by natural cooling or water quenching to a temperature of less than or equal to 100°C.

[0012] Preferably, the magnetic field strength of the first stage of magnetic separation is 0.2T, and the magnetic field strength of the second stage of magnetic separation is 0.15T.

[0013] Preferably, the titanium-bearing crude niobium concentrate is one of the following: artificial titanium-bearing crude niobium concentrate prepared from pure niobite minerals and pure ilmenite minerals, or titanium-bearing crude niobium concentrate obtained by flotation of various types of niobium-bearing ores and tailings from the Bayan Obo East and West Mines; wherein the various types of niobium-bearing ores from the Bayan Obo East and West Mines include one or more of the following: aegirine type, massive type, amphibole type, dolomite type, and mica type; the Nb2O5 grade in the titanium-bearing crude niobium concentrate is 5%–32%; and the TiO2 content is 10%–30%.

[0014] Preferably, the oxidative roasting is carried out in a muffle furnace, where the air remaining in the muffle furnace is used to provide an oxidative atmosphere so that the titanium minerals in the titanium-containing crude niobium concentrate undergo an oxidative transformation reaction in the oxidative atmosphere, while the niobium minerals do not undergo a phase transformation.

[0015] Preferably, the grade of Nb2O5 in the obtained niobium concentrate is 15% to 50%, and the recovery rate of Nb2O5 is 65% to 85%; the grade of TiO2 in the obtained titanium product is 20% to 40%, and the recovery rate of TiO2 is 70% to 95%.

[0016] Preferably, the present invention provides a method for separating niobium and titanium by oxidative roasting and magnetic separation of titanium-containing crude niobium concentrate, thereby obtaining niobium concentrate and titanium products.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0018] This invention provides a method for separating niobium and titanium through oxidative roasting and magnetic separation of titanium-containing crude niobium concentrate. The method involves oxidative roasting the titanium-containing crude niobium concentrate in a muffle furnace to achieve mineral reconstruction. Under this treatment, ilmenite in the titanium-containing crude niobium concentrate undergoes a phase transition, resulting in enhanced magnetism, while niobite in the titanium-containing crude niobium concentrate does not undergo a phase transition, so its magnetism remains unchanged. Therefore, by using wet magnetic separation based on the difference in magnetic properties between titanium minerals and niobite in the roasting product of the titanium-containing crude niobium concentrate, niobium and titanium can be separated, thus obtaining niobium concentrate and titanium products. This separation method simplifies the process flow in separation and upgrading, eliminating the need for reagents and enrichment / purification. Furthermore, the mineral reconstruction process during oxidative roasting achieves titanium and niobium separation based on the magnetic changes of ilmenite and niobium minerals, resulting in high-grade and high-recovery niobium concentrate and titanium products, optimizing the separation effect and improving the sustainability of the entire beneficiation process.

[0019] In this invention, the magnetic strength of ilmenite is altered by adjusting the oxidative roasting temperature. By comparing the magnetic properties of the roasted products from unroasted ilmenite and those from oxidative roasting at different temperatures, it was found that, compared to the unroasted form, the magnetic enhancement is most significant when the oxidative roasting temperature is 600℃ (see details). Figure 2 Meanwhile, the magnetic properties of the roasted products of unroasted niobite and those roasted at different oxidative roasting temperatures were compared and analyzed. The magnetic properties of unroasted niobite, or those roasted at different temperatures, remained essentially unchanged (see details). Figure 3 The fundamental principle of magnetic separation is based on the magnetic differences between minerals. Under reasonable process conditions, larger magnetic differences are generally beneficial to improving separation efficiency, and with comprehensive optimization, they are conducive to obtaining high-grade or high-recovery products. Therefore, based on the technical solution of amplifying the magnetic differences between niobium and titanium minerals, a roasting temperature of 600℃ was determined, and then magnetic separation was used to significantly improve the separation efficiency of niobium and titanium. Attached Figure Description

[0020] Figure 1 This is a flowchart of a method for promoting niobium-titanium separation through mineral reconstruction by oxidative roasting according to the present invention.

[0021] Figure 2 The VSM magnetic curves of the roasted products of ilmenite in the present invention are shown below, both before and after roasting at different oxidation roasting temperatures.

[0022] Figure 3 The VSM magnetic curves of the roasted products of niobium iron ore before roasting and at different oxidation roasting temperatures are shown in this invention. Detailed Implementation

[0023] The specific embodiments of the present invention are described in detail below, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention. Unless otherwise specified, the experimental methods described in the embodiments of the present invention are conventional methods.

[0024] The inventors discovered that it is difficult to effectively separate the two by directly using conventional magnetic separation or flotation, as their properties are very similar; however, the oxidative roasting method is an effective way to change the phase of minerals. Under high temperature conditions, the phase and properties of minerals will undergo certain changes.

[0025] In view of this, the present invention provides a product and separation method for promoting niobium-titanium separation through mineral reconstruction by oxidative roasting. This method simplifies the process flow in separation and upgrading, and obtains high-grade and high-recovery niobium concentrate and titanium products through oxidative roasting.

[0026] like Figure 1 As shown, this invention provides a method for promoting the separation of niobium concentrate and titanium products through oxidative roasting mineral reconstruction, comprising the following steps:

[0027] Titanium-containing crude niobium concentrate is reconstructed by oxidative roasting to cause a phase transformation in ilmenite, which enhances its magnetism. This changes the magnetic properties of ilmenite and niobite in the titanium-containing crude niobium concentrate. The oxidative roasting product after mineral reconstruction is then cooled.

[0028] The cooled oxidative roasting product undergoes a first-stage magnetic separation to obtain a first-stage magnetic product. This first-stage magnetic product is then subjected to a second-stage magnetic separation to obtain a titanium product. The non-magnetic product obtained from the first-stage magnetic separation is mixed with the non-magnetic product obtained from the second-stage magnetic separation to obtain niobium concentrate.

[0029] Specifically, the titanium-containing crude niobium concentrate is roasted in an oxidizing atmosphere at a temperature of 550℃~600℃ for 60min~120min. This oxidizing atmosphere is oxygen or air. The purpose of maintaining the oxidizing atmosphere for a certain period of time is to ensure the phase change of ilmenite, realize its magnetic evolution, and increase the magnetic difference between titanium minerals and niobite.

[0030] Specifically, the oxidative roasting product is cooled by natural cooling or water quenching to a temperature of less than or equal to 100°C. This cooling is to facilitate subsequent magnetic separation, as magnetic separation is difficult to achieve at high temperatures.

[0031] Specifically, the magnetic field strength for the first stage of magnetic separation is 0.2T, and the magnetic field strength for the second stage is 0.15T. Ilmenite undergoes a high-temperature phase transition, increasing the magnetic difference between titanium minerals and columbite. Experiments have shown that the appropriate magnetic field strength is 0.2T for the first stage and 0.15T for the second stage. If the magnetic field strength is too high or too low, the separation effect will be poor.

[0032] Specifically, the titanium-bearing crude niobium concentrate is one of the following: artificial titanium-bearing crude niobium concentrate prepared from pure columbite minerals and pure ilmenite minerals, or titanium-bearing crude niobium concentrate obtained by flotation from various types of niobium-bearing ores and tailings from the Bayan Obo East and West Mines; wherein the various types of niobium-bearing ores from the Bayan Obo East and West Mines include one or more of the following types: aegirine type, massive type, amphibole type, dolomite type, and mica type; the Nb2O5 grade in the titanium-bearing crude niobium concentrate is 5%–32%; and the TiO2 content is 10%–30%.

[0033] Specifically, the oxidative roasting is completed in a muffle furnace. The air remaining in the muffle furnace is used to provide an oxidative atmosphere for the titanium minerals in the titanium-containing crude niobium concentrate to undergo an oxidative transformation reaction. The oxidation reaction formula is as follows:

[0034] FeTiO3 + O2 → Fe3O4 + TiO2;

[0035] FeTiO3 + O2 → Fe2O3 + TiO2;

[0036] Specifically, the grade of Nb2O5 in niobium concentrate obtained by wet magnetic separation after reconstruction of oxidized roasted minerals is 15%–50%, and the recovery rate is 65%–85%; the grade of TiO2 in titanium product obtained by wet magnetic separation after reconstruction of oxidized roasted minerals is 20%–40%, and the recovery rate is 70%–95%.

[0037] The technical solution of the present invention will be further described below through specific embodiments. Experiments have shown that one type of titanium-bearing crude niobium concentrate obtained from flotation of various types of niobium-bearing ores and tailings from the Bayan Obo East and West mines can achieve niobium-titanium separation through oxidative roasting-magnetic separation. The following discussion focuses on an artificially mixed ore containing pure niobium-iron ore (Nb₂O₅ grade 47.28%, TiO₂ content 2.03%) and pure ilmenite (TiO₂ grade 53.00%).

[0038] Example 1

[0039] This embodiment deals with an artificially mixed ore containing pure columbite mineral (Nb2O5 grade 47.28%, TiO2 content 2.03%) and pure ilmenite mineral (TiO2 grade 53.00%). The two are thoroughly mixed at a 1:1 mass ratio, followed by oxidative roasting and magnetic separation. The raw material has a Nb2O5 grade of 23.64% and a TiO2 grade of 27.52%.

[0040] A method for separating niobium and titanium from titanium-containing crude niobium concentrate by oxidative roasting and magnetic separation, comprising the following specific steps:

[0041] Ilmenite and columbite minerals were thoroughly mixed at a mass ratio of 1:1 to obtain an artificial mixed ore. During roasting, the temperature was increased from room temperature to 550°C at a rate of 15°C / min. The artificial mixed ore was then oxidatively roasted at 550°C for 2 hours. After the roasting period, the material was cooled to 100°C. The cooled oxidatively roasted product was then subjected to magnetic separation.

[0042] The oxidized roasted product obtained after cooling was subjected to a two-stage wet magnetic separation. The first stage had a magnetic field strength of 0.2T. The magnetic product obtained from the first stage was then subjected to a second stage of magnetic separation with a magnetic field strength of 0.15T. The non-magnetic products obtained from the first and second stages of magnetic separation were mixed to form niobium concentrate, with a yield of 44.46%, an Nb₂O₅ grade of 38.40%, an Nb₂O₅ recovery rate of 72.21%, and a TiO₂ content of 5.84%. The magnetic product obtained from the second stage of magnetic separation was titanium, with a TiO₂ grade of 45.07%, a TiO₂ recovery rate of 90.56%, and an Nb₂O₅ content of 11.88%.

[0043] In this embodiment, niobium concentrate and titanium products were obtained through oxidative roasting and magnetic separation. The niobium concentrate yield was 44.46%, the Nb₂O₅ grade was 38.40%, the Nb₂O₅ recovery rate was 72.21%, and the TiO₂ content was 5.84%. The titanium product had a TiO₂ grade of 45.07%, a TiO₂ recovery rate of 90.56%, and an Nb₂O₅ content of 11.88%.

[0044] Example 2

[0045] This embodiment deals with an artificially mixed ore containing pure columbite mineral (Nb2O5 grade 47.28%, TiO2 content 2.03%) and pure ilmenite mineral (TiO2 grade 53.00%). The two are thoroughly mixed at a 1:1 mass ratio, followed by oxidative roasting and magnetic separation. The raw material has a Nb2O5 grade of 23.64% and a TiO2 grade of 27.52%.

[0046] A method for separating niobium and titanium from titanium-containing crude niobium concentrate by oxidative roasting and magnetic separation, comprising the following specific steps:

[0047] Ilmenite and columbite minerals were thoroughly mixed at a mass ratio of 1:1 to obtain an artificial mixed ore. During roasting, the temperature was increased from room temperature to 575°C at a rate of 15°C / min. The artificial mixed ore was then oxidatively roasted at 575°C for 2 hours. After the roasting period, the material was cooled to 100°C. The cooled oxidatively roasted product was then subjected to magnetic separation.

[0048] The oxidized roasted product obtained after cooling was subjected to a two-stage wet magnetic separation. The first stage had a magnetic field strength of 0.2T. The magnetic product obtained from the first stage was then subjected to a second stage of magnetic separation with a magnetic field strength of 0.15T. The non-magnetic products obtained from the first and second stages of magnetic separation were mixed to form niobium concentrate, with a yield of 44.68%, an Nb₂O₅ grade of 40.65%, an Nb₂O₅ recovery rate of 76.81%, and a TiO₂ content of 4.83%. The magnetic product obtained from the second stage of magnetic separation was titanium, with a TiO₂ grade of 45.80%, a TiO₂ recovery rate of 92.16%, and an Nb₂O₅ content of 9.90%.

[0049] In this embodiment, niobium concentrate and titanium products were obtained through oxidative roasting and magnetic separation. The niobium concentrate yield was 44.68%, the Nb₂O₅ grade was 40.65%, the Nb₂O₅ recovery rate was 76.81%, and the TiO₂ content was 4.83%. The titanium product had a TiO₂ grade of 45.80%, a TiO₂ recovery rate of 92.16%, and an Nb₂O₅ content of 9.90%.

[0050] Example 3

[0051] This embodiment deals with an artificially mixed ore containing pure columbite mineral (Nb2O5 grade 47.28%, TiO2 content 2.03%) and pure ilmenite mineral (TiO2 grade 53.00%). The two are thoroughly mixed at a 1:1 mass ratio, followed by oxidative roasting and magnetic separation. The raw material has a Nb2O5 grade of 23.64% and a TiO2 grade of 27.52%.

[0052] A method for separating niobium and titanium from titanium-containing crude niobium concentrate by oxidative roasting and magnetic separation, comprising the following specific steps:

[0053] Ilmenite and columbite minerals were thoroughly mixed at a mass ratio of 1:1 to obtain an artificial mixed ore. During roasting, the temperature was increased from room temperature to 600℃ at a rate of 15℃ / min. The artificial mixed ore was then oxidatively roasted at 600℃ for 2 hours. After the roasting period, the material was cooled to 100℃. The cooled oxidatively roasted product was then subjected to magnetic separation.

[0054] The oxidized roasted product obtained after cooling was subjected to a two-stage wet magnetic separation. The first stage had a magnetic field strength of 0.2T. The magnetic product obtained from the first stage was then subjected to a second stage of magnetic separation with a magnetic field strength of 0.15T. The non-magnetic products obtained from the first and second stages of magnetic separation were mixed to form niobium concentrate, with a yield of 46.96%, an Nb₂O₅ grade of 40.77%, an Nb₂O₅ recovery rate of 80.99%, and a TiO₂ content of 6.19%. The magnetic product obtained from the second stage of magnetic separation was titanium, with a TiO₂ grade of 46.09%, a TiO₂ recovery rate of 89.43%, and an Nb₂O₅ content of 8.42%.

[0055] In this embodiment, niobium concentrate and titanium products were obtained through oxidative roasting and magnetic separation. The niobium concentrate yield was 46.96%, the Nb₂O₅ grade was 40.77%, the Nb₂O₅ recovery rate was 80.99%, and the TiO₂ content was 6.19%. The titanium product had a TiO₂ grade of 46.09%, a TiO₂ recovery rate of 89.43%, and an Nb₂O₅ content of 8.42%.

[0056] Example 4

[0057] In this embodiment, the minerals processed are pure columbite ore (Nb2O5 grade 47.28%, TiO2 content 2.03%) and pure ilmenite ore (TiO2 grade 53.00%). They are roasted separately at a 1:1 mass ratio, then fully mixed and separated by magnetic separation. The Nb2O5 grade in the artificially mixed ore raw material is 23.64%, and the TiO2 grade is 27.52%.

[0058] A method for separating niobium and titanium from titanium-containing crude niobium concentrate by oxidative roasting and magnetic separation, comprising the following specific steps:

[0059] Pure columbite ore and pure ilmenite were roasted separately at a mass ratio of 1:1. During roasting, both pure columbite ore and pure ilmenite were heated from room temperature to 600℃ at a heating rate of 15℃ / min. They were then oxidatively roasted at 600℃ for 2 hours, and after the holding period, the materials were cooled to 100℃. The two oxidatively roasted products were then thoroughly mixed.

[0060] The oxidized roasted product obtained after cooling was subjected to a two-stage wet magnetic separation. The first stage had a magnetic field strength of 0.2T, yielding both magnetic and non-magnetic products. The magnetic product from the first stage was then subjected to a second stage of magnetic separation with a magnetic field strength of 0.15T. The non-magnetic products from both stages were mixed to form niobium concentrate, with a yield of 35.40%, an Nb₂O₅ grade of 45.55%, an Nb₂O₅ recovery rate of 68.20%, and a TiO₂ content of 7.11%. The magnetic product obtained from the second stage was titanium, with a TiO₂ grade of 38.31%, a TiO₂ recovery rate of 90.86%, and an Nb₂O₅ content of 11.52%.

[0061] In this embodiment, niobium concentrate and titanium products were obtained through oxidative roasting-magnetic separation. The yield of the niobium concentrate was 35.40%, the Nb2O5 grade was 45.55%, the Nb2O5 recovery rate was 68.20%, and the TiO2 content was 7.11%. The titanium product had a TiO2 grade of 38.31%, a TiO2 recovery rate of 90.86%, and an Nb2O5 content of 11.52%.

[0062] Compare with Example 1

[0063] The comparative example involved pure columbite ore (Nb2O5 grade 47.28%, TiO2 content 2.03%) and pure ilmenite ore (TiO2 grade 53.00%), which were thoroughly mixed at a 1:1 mass ratio and then separated by magnetic separation. The Nb2O5 grade in the artificially mixed ore raw material was 23.64%, and the TiO2 grade was 27.52%.

[0064] Unlike Example 4, in this Comparative Example 1, the artificially prepared titanium-containing crude niobium was directly separated by magnetic separation, including the following specific steps:

[0065] Pure columbite and ilmenite minerals were thoroughly mixed at a mass ratio of 1:1. The resulting artificially mixed ore was then subjected to a two-stage wet magnetic separation. The first stage used a magnetic field strength of 0.2T, yielding both magnetic and non-magnetic products. The magnetic product from the first stage was then subjected to a second stage of magnetic separation with a magnetic field strength of 0.15T. The non-magnetic products from the first and second stages of magnetic separation were mixed to form niobium concentrate, with a yield of 44.48%, an Nb₂O₅ grade of 30.35%, an Nb₂O₅ recovery rate of 57.11%, and a TiO₂ content of 12.28%. The magnetic product obtained from the second stage of magnetic separation was titanium, with a TiO₂ grade of 39.72%, a TiO₂ recovery rate of 80.15%, and an Nb₂O₅ content of 18.26%.

[0066] In this comparative example 1, niobium concentrate and titanium products were obtained by direct magnetic separation. The yield of the niobium concentrate was 44.48%, the grade of Nb₂O₅ was 30.35%, the recovery rate of Nb₂O₅ was 57.11%, and the TiO₂ content was 12.28%. The TiO₂ content of the titanium product was 39.72%, the recovery rate of TiO₂ was 80.15%, and the Nb₂O₅ content was 18.26%.

[0067] This invention also provides a method for separating niobium and titanium through oxidation roasting and magnetic separation of nepheline-type niobium ore from the Bayan Obo East Mine and mica-type niobium ore from the Bayan Obo West Mine. The technical solution of this invention will be further described below with specific embodiments.

[0068] Example 5

[0069] This embodiment processes crude niobium concentrate obtained from the flotation of nephrite-type niobium ore from the main eastern mine of Bayan Obo, with a Nb2O5 grade of 5.48% and a TiO2 grade of 23.21%. The niobium mineral is mainly columbite, and the titanium mineral is mainly ilmenite.

[0070] A method for separating niobium and titanium from titanium-containing crude niobium concentrate by oxidative roasting and magnetic separation, comprising the following specific steps:

[0071] The crude niobium concentrate obtained from the flotation of nephrite-type niobium ore in the main eastern mine of Bayan Obo was roasted. During roasting, the temperature was increased from room temperature to 600℃ at a rate of 15℃ / min, held at that temperature for 40 minutes, and then oxidized and roasted at 600℃ for 2 hours. After the holding period, the material was cooled to 100℃. Then, the two oxidized roasted products were thoroughly mixed evenly.

[0072] The oxidized roasted product obtained after cooling was subjected to a two-stage wet magnetic separation. The magnetic field strength in the first stage was 0.20T. The magnetic product obtained from the first stage was then subjected to a second stage of magnetic separation with a magnetic field strength of 0.15T. The non-magnetic products obtained from the first and second stages of magnetic separation were mixed to form niobium concentrate, with a yield of 26.90%, an Nb₂O₅ grade of 15.72%, an Nb₂O₅ recovery rate of 77.19%, and a TiO₂ content of 10.17%. The magnetic product obtained from the second stage of magnetic separation was titanium, with a yield of 73.10%, a TiO₂ grade of 28.01%, a TiO₂ recovery rate of 88.22%, and an Nb₂O₅ content of 1.71%.

[0073] In this embodiment, niobium concentrate and titanium products were obtained through oxidative roasting-magnetic separation. The niobium concentrate yield was 26.90%, the Nb₂O₅ grade was 15.72%, the Nb₂O₅ recovery rate was 77.19%, and the TiO₂ content was 10.17%. The titanium product yield was 73.10%, the TiO₂ grade was 28.01%, the TiO₂ recovery rate was 88.22%, and the Nb₂O₅ content was 1.71%.

[0074] Example 6

[0075] This embodiment deals with crude niobium concentrate obtained from the flotation of mica-type niobium ore from the Bayan Obo West Mine, in which the grade of Nb2O5 is 5.99% and the grade of TiO2 is 7.42%. The niobium mineral is mainly columbite and the titanium mineral is mainly ilmenite.

[0076] A method for separating niobium and titanium from titanium-containing crude niobium concentrate by oxidative roasting and magnetic separation, comprising the following specific steps:

[0077] The crude niobium concentrate obtained from the flotation of mica-type niobium ore from the Bayan Obo West Mine was roasted. During roasting, the niobium concentrate obtained from flotation was heated from room temperature to 600℃ at a heating rate of 15℃ / min, and then oxidized and roasted at 600℃ for 2 hours. After the holding period, the material was cooled to 100℃. Then, the two oxidized roasted products after roasting and cooling were thoroughly mixed evenly.

[0078] The oxidized roasted product obtained after cooling was subjected to a two-stage wet magnetic separation. The first stage had a magnetic field strength of 0.2T, and the magnetic product obtained from the first stage was then subjected to a second stage of magnetic separation with a magnetic field strength of 0.15T. The non-magnetic products obtained from the first and second stages of magnetic separation, when mixed, constituted niobium concentrate with a yield of 45.69%, an Nb₂O₅ grade of 9.82%, an Nb₂O₅ recovery rate of 74.89%, and a TiO₂ content of 2.51%. The magnetic product obtained from the second stage of magnetic separation was titanium, with a TiO₂ grade of 12.04%, a TiO₂ recovery rate of 84.52%, and an Nb₂O₅ content of 2.89%.

[0079] In this embodiment, niobium concentrate and titanium products were obtained through oxidative roasting and magnetic separation. The niobium concentrate yield was 45.69%, the Nb₂O₅ grade was 9.82%, the Nb₂O₅ recovery rate was 74.89%, and the TiO₂ content was 2.51%. The titanium product had a TiO₂ grade of 12.04%, a TiO₂ recovery rate of 84.52%, and an Nb₂O₅ content of 2.89%.

[0080] Compare with Example 2

[0081] The comparative example in this paper deals with pure ilmenite mineral with a TiO2 grade of 53.00%, and the pure ilmenite mineral is unroasted.

[0082] Compare with Example 3

[0083] The comparative example in this paper deals with pure ilmenite mineral, with a TiO2 grade of 53.00%.

[0084] Ilmenite pure mineral was roasted by heating it from room temperature to 500°C at a rate of 15°C / min; then it was oxidatively roasted at 500°C for 2 hours, and after the roasting period, the material was cooled to 100°C to obtain the roasted product.

[0085] Compare with Example 4

[0086] The comparative example in this paper deals with pure ilmenite mineral, with a TiO2 grade of 53.00%.

[0087] Ilmenite pure mineral was roasted by heating it from room temperature to 700°C at a rate of 15°C / min; then it was oxidatively roasted at 700°C for 2 hours, and after the roasting period, the material was cooled to 100°C to obtain the roasted product.

[0088] Compare with Example 5

[0089] The comparative example in this paper deals with pure ilmenite mineral, with a TiO2 grade of 53.00%.

[0090] Ilmenite pure mineral was roasted by heating it from room temperature to 800°C at a rate of 15°C / min; then it was oxidatively roasted at 800°C for 2 hours, and after the roasting period, the material was cooled to 100°C to obtain the roasted product.

[0091] Compare with Example 6

[0092] The comparative example in this paper deals with pure ilmenite mineral, with a TiO2 grade of 53.00%.

[0093] Ilmenite pure mineral was roasted by heating it from room temperature to 900℃ at a rate of 15℃ / min; then it was oxidatively roasted at 900℃ for 2 hours, and after the roasting period, the material was cooled to 100℃ to obtain the roasted product.

[0094] Compare with Example 7

[0095] The comparative example in this paper deals with pure ilmenite mineral, with a TiO2 grade of 53.00%.

[0096] Ilmenite pure mineral was roasted by heating it from room temperature to 1000℃ at a rate of 15℃ / min; then it was oxidatively roasted at 1000℃ for 2 hours, and after the roasting period, the material was cooled to 100℃ to obtain the roasted product.

[0097] Comparative Example 8

[0098] The subject of this comparative example is pure columbite mineral with a Nb₂O₅ grade of 47.28%. This pure columbite mineral was not roasted.

[0099] Comparative Example 9

[0100] The comparative example in this paper deals with pure columbite mineral, with a Nb2O5 grade of 47.28%.

[0101] The pure columbite ore mineral was roasted. During roasting, the pure columbite ore mineral was heated from room temperature to 700℃ at a heating rate of 15℃ / min; then oxidatively roasted at 700℃ for 2 hours. After the holding period, the material was cooled to 100℃ to obtain the roasted product.

[0102] Comparative Example 10

[0103] The comparative example in this paper deals with pure columbite mineral, with a Nb2O5 grade of 47.28%.

[0104] The pure columbite ore mineral was roasted. During roasting, the pure columbite ore mineral was heated from room temperature to 800℃ at a heating rate of 15℃ / min; then oxidatively roasted at 800℃ for 2 hours. After the holding period, the material was cooled to 100℃ to obtain the roasted product.

[0105] Compare with Example 11

[0106] The comparative example in this paper deals with pure columbite mineral, with a Nb2O5 grade of 47.28%.

[0107] The pure columbite ore mineral was roasted. During roasting, the pure columbite ore mineral was heated from room temperature to 900℃ at a heating rate of 15℃ / min; then oxidatively roasted at 900℃ for 2 hours. After the holding period, the material was cooled to 100℃ to obtain the roasted product.

[0108] Compare with Example 12

[0109] The comparative example in this paper deals with pure columbite mineral, with a Nb2O5 grade of 47.28%.

[0110] The pure columbite ore mineral was roasted. During roasting, the pure columbite ore mineral was heated from room temperature to 1000℃ at a heating rate of 15℃ / min; then it was oxidatively roasted at 1000℃ for 2 hours. After the holding period, the material was cooled to 100℃ to obtain the roasted product.

[0111] Experimental Test

[0112] (1) Selection of magnetic roasting temperature for ilmenite

[0113] The roasted ilmenite from Example 4 and the ilmenite obtained in Comparative Examples 2 to 7 were subjected to VSM magnetic analysis. The VSM magnetic analysis results are as follows: Figure 2 As shown, by comparing the magnetic properties of ilmenite products before and after oxidative roasting at different temperatures, it was found that the magnetic enhancement was most significant when the oxidative roasting temperature was 600℃.

[0114] (2) Selection of magnetic roasting temperature for niobium iron ore

[0115] The roasted columbite from Example 4 and the ilmenite obtained from Comparative Examples 8 to 12 were subjected to VSM magnetic analysis. The VSM magnetic analysis results are as follows: Figure 3 As shown, by comparing the magnetic properties of ilmenite when it is unroasted and when roasted at different oxidative roasting temperatures, it can be seen that the magnetic properties of niobite remain basically unchanged when it is unroasted or roasted at different temperatures.

[0116] In summary, at a roasting temperature of 600℃, the technical solution based on amplifying the magnetic differences between niobium and titanium minerals can significantly improve the separation efficiency of niobium and titanium through magnetic separation. This is because the fundamental principle of magnetic separation is based on the magnetic differences between minerals. Under reasonable process conditions, larger magnetic differences are generally beneficial to improving separation efficiency, and with comprehensive optimization, it is conducive to obtaining high-grade or high-recovery products.

[0117] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A method for separating niobium and titanium by oxidizing roasting-magnetic separation of a crude niobium concentrate containing titanium, characterized in that, The method comprises the following steps: The titanium-containing crude niobium concentrate is subjected to mineral reconstruction by oxidative roasting to cause phase change of ilmenite in the titanium-containing crude niobium concentrate and enhance the magnetism, so that the magnetism of ilmenite and niobium minerals in the titanium-containing crude niobium concentrate is changed, the oxidative roasting product after mineral reconstruction is subjected to cooling treatment, and the titanium-containing crude niobium concentrate is roasted in an oxidizing atmosphere at a temperature of 550-600 ℃ for 60-120 min; The cooled oxidative roasting product is subjected to one-stage magnetic separation to obtain one-stage magnetic product, and then the one-stage magnetic product is subjected to two-stage magnetic separation to obtain a magnetic product as a titanium product, the non-magnetic product obtained by one-stage magnetic separation is mixed with the non-magnetic product obtained by two-stage magnetic separation to obtain a niobium concentrate, the magnetic field strength for one-stage magnetic separation is 0.2 T, and the magnetic field strength for two-stage magnetic separation is 0.15 T, the titanium-containing crude niobium concentrate is subjected to mineral reconstruction by oxidative roasting, the ilmenite in the titanium-containing crude niobium concentrate is subjected to phase change to enhance the magnetism, the niobium iron ore in the titanium-containing crude niobium concentrate is not subjected to phase change, and the magnetism of the niobium iron ore is not changed, so that the separation of niobium and titanium can be realized by wet magnetic separation of the titanium minerals and the niobium iron ore in the roasting product of the titanium-containing crude niobium concentrate according to the magnetism, and the niobium concentrate and the titanium product are obtained.

2. The method for realizing separation of niobium and titanium by oxidizing roasting-magnetic separation of titanium-containing crude niobium concentrate according to claim 1, characterized in that, The oxidative roasting product is subjected to cooling treatment by natural cooling or water quenching, and the oxidative roasting product is cooled to a temperature of less than or equal to 100 ℃.

3. The method for realizing separation of niobium and titanium by oxidizing roasting-magnetic separation of titanium-containing crude niobium concentrate according to claim 1, characterized in that, The titanium-containing crude niobium concentrate is one of artificial titanium-containing crude niobium concentrate prepared from pure niobite and pure ilmenite, and titanium-containing crude niobium concentrate obtained by flotation from each type of niobium-containing ore and tailings in East and West mines of Baiyunebo, wherein each type of niobium-containing ore in East and West mines of Baiyunebo includes one or more of nepheline type, block type, amphibole type, dolomite type and mica type, the grade of Nb2O5 in the titanium-containing crude niobium concentrate is 5%-32%, and the content of TiO2 is 10%-30%.

4. The method for realizing separation of niobium and titanium by oxidizing roasting-magnetic separation of titanium-containing crude niobium concentrate according to claim 1, characterized in that, The grade of Nb2O5 in the obtained niobium concentrate is 15%-50%, the recovery rate of Nb2O5 is 65%-85%, the grade of TiO2 in the obtained titanium product is 20%-40%, and the recovery rate of TiO2 is 70%-95%.

5. The niobium concentrate and titanium product obtained by the method for separating niobium and titanium by oxidative roasting and magnetic separation of the titanium-containing crude niobium concentrate according to any one of claims 1-4.

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