Method for realizing comprehensive utilization of titanium ore by suspension roasting in steps

Abstract

The present application relates to a kind of by suspension roasting step-by-step realization titanium ore comprehensive utilization method, belong to mineral processing technical field.The present application is by suspension roasting step-by-step realization titanium ore comprehensive utilization method, including the following steps: suspension magnetization roasting-weak magnetic separation enrichment iron concentrate-suspension oxidation roasting-magnetic separation realizes titanium chromium separation;Utilize suspension roasting technology and magnetic separation technology combination, utilize the specific fluidized roasting advantage of suspension roasting, control the reduction degree of iron mineral and the oxidation degree of ilmenite, step-by-step realization ilmenite mineral and ilmenite mineral magnetization, reduce the stockpiling of titanium ore, vitalize ilmenite resource, while obtaining high-grade iron concentrate, titanium concentrate, effectively separate chromite, and then realize the comprehensive utilization of titanium ore resource.

Description

Technical Field

[0001] This invention relates to the field of mineral processing technology, specifically to a method for the comprehensive utilization of titanium ore through a stepwise suspension roasting process. Background Technology

[0002] Ilmenite is an oxide mineral of iron and titanium, also known as titanomagnetite, and is the main ore for titanium refining. Its main component is FeTiO3. It also contains impurity elements such as CaO, MgO, SiO2, Al2O3, MnO2, V2O5, and Cr2O3. The content of these impurity elements has a direct impact on the quality of ilmenite products. The common beneficiation process is a combination of traditional gravity separation, dry magnetic separation, and electrostatic separation.

[0003] Chromium in ilmenite typically exists as chromite. Due to the similar physical properties of ilmenite, chromite, and ilmenite-hematite, conventional methods such as gravity separation, magnetic separation, electrostatic separation, or a combination of these methods are insufficient to effectively separate chromium and iron. Currently, this type of titanium concentrate containing weakly magnetic gangue minerals can only be stored as tailings. Therefore, finding an economical and efficient way to separate chromium and iron from ilmenite is of paramount importance for the comprehensive utilization of titanium raw materials.

[0004] Patent CN103316761A discloses a method for separating ore containing ilmenite and chromite: The ore containing ilmenite and chromite is separated using gravity separation or a "weak magnetic-strong magnetic" process, with some gangue minerals (tailings) pre-removed to enrich chromite and ilmenite, forming a mixed rough concentrate of ilmenite and chromite; the mixed rough concentrate of ilmenite and chromite produced by the above process is then oxidized and roasted using a rotary kiln, fluidized bed, or fluidized bed furnace, followed by natural cooling; the oxidized and roasted material is then separated using a dry medium-strong magnetic separation process to obtain ilmenite concentrate and chromite concentrate. This process does not mention the separation of ilmenite containing weakly magnetic gangue minerals, and rotary kilns and fluidized beds have drawbacks such as high investment, large footprint, poor processing capacity, low reduction efficiency, and high energy consumption.

[0005] Patent CN111118281A discloses a method for separating titanium and iron from coastal sand deposits using suspension roasting: The coastal sand deposits are gravity separated to obtain a gravity concentrate, which is then ground into powder and subjected to weak magnetic separation to obtain strongly magnetic iron minerals and a first-stage tailings. The first-stage tailings are fed into a suspension roasting furnace, where they are heated, oxidized, reduced, and cooled before being discharged. After being air-cooled to room temperature, a second stage of weak magnetic separation is performed to obtain a second-stage magnetic concentrate and a second-stage magnetic tailings. The second-stage magnetic tailings are used as titanium concentrate, with a titanium dioxide mass percentage ≥50%. The second-stage magnetic concentrate and the strongly magnetic iron minerals are combined to form an iron concentrate. This invention employs a simple suspension roasting process, has a large equipment capacity, produces stable product performance, is energy-saving and environmentally friendly for industrial application, and is easily scaled up. However, it fails to effectively separate chromite from the titanium concentrate. Summary of the Invention

[0006] To address the aforementioned problems in the separation of titanium and chromium in titanium concentrate (medium-sized) ore, this invention provides a method for the comprehensive utilization of titanium ore through stepwise suspension roasting.

[0007] A method for comprehensive utilization of titanium ore through stepwise suspension roasting includes the following steps:

[0008] Step 1: Suspension magnetization calcination

[0009] The titanium ore raw material contains 40%-50% Fe2O3, 30%-40% TiO2, and less than 10% Cr2O3. The titanium ore raw material is crushed and ground to a particle size of -0.3mm, of which 65%-80% are of particle size of -0.15mm. Then it is subjected to suspension reduction roasting, in which it is mixed and reduced with reducing gas in a suspended state to obtain reduced roasted sand.

[0010] Step 2: Weak magnetic separation to enrich iron concentrate

[0011] The reduced roasted sand is first subjected to a weak magnetic separation to obtain a weak magnetic concentrate and a weak magnetic tailings; the weak magnetic concentrate is then subjected to a second weak magnetic separation to obtain an iron concentrate and a weak magnetic tailings.

[0012] Step 3: Suspension oxidation roasting

[0013] The first and second weak magnetic tailings are dehydrated, dried and mixed, and then subjected to suspension oxidation roasting. They are mixed with air in a suspended state to obtain oxidized roasted sand; the oxidizing gas is compressed air.

[0014] Step 4: Magnetic separation to achieve titanium-chromium separation

[0015] The feed is oxidized roasted sand, which is subjected to weak magnetic separation to obtain titanium concentrate and weak magnetic tailings. The weak magnetic tailings are chromium-containing concentrate, thus realizing the separation of ilmenite and chromite.

[0016] Furthermore, the reducing gas mentioned in step 1 is a mixture of CO and N2, wherein the CO concentration is 10%-60%.

[0017] Furthermore, the reduction temperature is 480℃-580℃, and the reduction time is 5min-60min.

[0018] Furthermore, the magnetic field strength of the first stage of weak magnetic separation described in step 2 is 1000Gs-2000Gs, and the magnetic field strength of the second stage of weak magnetic separation is 600Gs-1500Gs.

[0019] Furthermore, the oxidation temperature in step 3 is 600℃-1200℃, and the oxidation time is 5min-120min.

[0020] Furthermore, the field strength of the weak magnetic separation described in step 4 is 2000Gs-4000Gs.

[0021] Furthermore, the iron concentrate described in step 2 has a TFe grade of 60%-63%, a TFe recovery rate of 20%-30%, and a TiO2 content of less than 12%.

[0022] Furthermore, in step 4, the titanium concentrate contains 40%-50% TiO2, has a TiO2 recovery rate of 70%-90%, and a Cr2O3 content of less than 0.2%; the chromium concentrate contains 20%-30% Cr2O3, 20%-30% TFe, and 20%-30% TiO2.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0024] By altering the magnetic properties of minerals through suspension roasting, weak magnetic fields can be used to achieve the purpose of selecting iron and titanium, while effectively separating chromium impurities from titanium concentrate.

[0025] This invention provides a new energy-saving and efficient method for separating ilmenite, reducing the stockpiling of ilmenite and revitalizing ilmenite resources. While obtaining high-grade iron and titanium concentrates, it effectively separates chromite, thereby achieving comprehensive utilization of ilmenite resources. The method combines suspension roasting and magnetic separation technologies, leveraging the unique fluidized bed roasting advantages of suspension roasting. By adjusting suitable roasting atmosphere, temperature, and time, the reduction degree of iron minerals and the oxidation degree of ilmenite are controlled, achieving stepwise magnetization of iron and ilmenite in the ilmenite. The method utilizes the magnetic differences between different ores to achieve the goal of separating iron, titanium, and chromium. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the process for the comprehensive utilization of titanium ore through a step-by-step suspension roasting method according to the present invention. Detailed Implementation

[0027] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0028] Figure 1 This is a schematic diagram of the mineral processing method according to an embodiment of the present invention.

[0029] Example 1

[0030] The main mineral composition of the titanium middlings raw material described in this embodiment is: ilmenite, ilmenite, a small amount of chromite, and trace amounts of zircon, monazite, and quartz. The titanium middlings raw material contains 47.20% Fe2O3, 36.30% TiO2, and 6.42% Cr2O3, with a particle size of -0.3 mm, of which the content of -0.15 mm is about 73%. If the particle size is too coarse, it will lead to poor monomer liberation and affect subsequent beneficiation operations.

[0031] This implementation plan is in accordance with Figure 1 Perform the steps shown:

[0032] 1. Suspension magnetization roasting: Titanium ore raw material is fed into a suspension roasting furnace and mixed with reducing gas in a suspended state for reduction. The reduction temperature is 540℃, the reduction time is 15min, and the reducing gas concentration is 40% (a mixture of CO and N2 gas). After the reduction is completed, reduced roasted sand is obtained.

[0033] 2. Two-stage weak magnetic separation of iron concentrate: The feed is reduced roasted sand. First, a weak magnetic separation is carried out with a magnetic field strength of 1650 Gs to obtain a weak magnetic concentrate and a weak magnetic tailings. The weak magnetic concentrate is then subjected to a second weak magnetic separation with a magnetic field strength of 1000 Gs to obtain iron concentrate and a weak magnetic tailings.

[0034] 3. Suspension oxidation roasting: After dehydration and drying, the tailings from the first stage of magnetic separation are fed into the suspension roasting furnace and mixed with air for oxidation. The oxidation temperature is 750℃, the oxidation time is 60min, and the oxidation gas is compressed air. After oxidation, oxidized roasted sand is obtained.

[0035] 4. Magnetic separation for titanium-chromium separation: The feed is oxidized roasted sand, which undergoes weak magnetic separation at a field strength of 2800 Gs to obtain titanium concentrate and weakly magnetic tailings. The weakly magnetic tailings are chromium-bearing concentrate, thus achieving the separation of ilmenite and chromite. The final titanium concentrate has a TiO2 content of 48.44%, a TiO2 recovery rate of 83.57%, and a Cr2O3 content of 0.17%; the iron concentrate has a TFe grade of 61.25%, a TFe recovery rate of 25.04%, and a TiO2 content of 11.99%; and the chromium-bearing concentrate has a Cr2O3 grade of 22.40%, a TFe grade of 26.03%, and a TiO2 grade of 23.38%.

[0036] Example 2

[0037] The main mineral composition of the titanium ore raw material described in this embodiment is: ilmenite, ilmenite, a small amount of chromite, and trace amounts of zircon, monazite, and quartz. The titanium ore raw material contains 49.32% Fe2O3, 37.61% TiO2, and 7.36% Cr2O3, with a particle size of -0.3 mm, of which the content of -0.15 mm is about 78%.

[0038] A method for comprehensive utilization of titanium ore through stepwise suspension roasting includes the following steps:

[0039] 1. Suspension magnetization roasting: Titanium ore raw material is fed into a suspension roasting furnace and mixed with reducing gas in a suspended state for reduction. The reduction temperature is 520℃, the reduction time is 20min, and the reducing gas concentration is 40% (a mixture of CO and N2 gas). After the reduction is completed, reduced roasted sand is obtained.

[0040] 2. Two-stage weak magnetic separation of iron concentrate: The feed is reduced roasted sand. First, a weak magnetic separation is carried out with a magnetic field strength of 1800 Gs to obtain a weak magnetic concentrate and a weak magnetic tailings. The weak magnetic concentrate is then subjected to a second weak magnetic separation with a magnetic field strength of 1000 Gs to obtain iron concentrate and a weak magnetic tailings.

[0041] 3. Suspension oxidation roasting: After dehydration and drying, the tailings from the first stage of magnetic separation are fed into the suspension roasting furnace and mixed with air for oxidation. The oxidation temperature is 800℃, the oxidation time is 50min, and the oxidation gas is compressed air. After oxidation, oxidized roasted sand is obtained.

[0042] 4. Magnetic separation for titanium-chromium separation: The feed is oxidized roasted sand, which undergoes weak magnetic separation at a field strength of 2800 Gs to obtain titanium concentrate and weakly magnetic tailings. The weakly magnetic tailings are chromium-bearing concentrate, thus achieving the separation of ilmenite and chromite. The final titanium concentrate has a TiO2 content of 47.69%, a TiO2 recovery rate of 84.07%, and a Cr2O3 content of 0.16%; the iron concentrate has a TFe grade of 60.78%, a TFe recovery rate of 25.72%, and a TiO2 content of 10.86%; and the chromium-bearing concentrate has a Cr2O3 grade of 27.36%, a TFe grade of 25.40%, and a TiO2 grade of 22.57%.

[0043] Example 3

[0044] The main mineral composition of the titanium ore raw material described in this embodiment is: ilmenite, ilmenite, a small amount of chromite, and trace amounts of zircon, monazite, and quartz. The titanium ore raw material contains 48.28% Fe2O3, 38.82% TiO2, and 5.61% Cr2O3, with a particle size of -0.3 mm, of which the content of -0.15 mm is about 70%.

[0045] A method for comprehensive utilization of titanium ore through stepwise suspension roasting includes the following steps:

[0046] 1. Suspension magnetization roasting: Titanium ore raw material is fed into a suspension roasting furnace and mixed with reducing gas in a suspended state for reduction. The reduction temperature is 560℃, the reduction time is 30min, and the reducing gas concentration is 50% (a mixture of CO and N2 gas). After the reduction is completed, reduced roasted sand is obtained.

[0047] 2. Two-stage weak magnetic separation of iron concentrate: The feed is reduced roasted sand. First, a weak magnetic separation is carried out with a magnetic field strength of 1650 Gs to obtain a weak magnetic concentrate and a weak magnetic tailings. The weak magnetic concentrate is then subjected to a second-stage weak magnetic separation with a magnetic field strength of 800 Gs to obtain iron concentrate and a weak magnetic tailings.

[0048] 3. Suspension oxidation roasting: After dehydration and drying, the tailings from the first stage of magnetic separation are fed into the suspension roasting furnace and mixed with air for oxidation. The oxidation temperature is 750℃, the oxidation time is 60min, and the oxidizing gas is compressed air. After oxidation, oxidized roasted sand is obtained.

[0049] 4. Magnetic separation for titanium-chromium separation: The feed is oxidized roasted sand, which undergoes weak magnetic separation at a field strength of 3000 Gs to obtain titanium concentrate and weakly magnetic tailings. The weakly magnetic tailings are chromium-bearing concentrate, thus achieving the separation of ilmenite and chromite. The final titanium concentrate has a TiO2 content of 49.98%, a TiO2 recovery rate of 85.20%, and a Cr2O3 content of 0.15%; the iron concentrate has a TFe grade of 62.53%, a TFe recovery rate of 27.03%, and a TiO2 content of 10.36%; and the chromium-bearing concentrate has a Cr2O3 grade of 27.36%, a TFe grade of 25.40%, and a TiO2 grade of 22.57%.

[0050] Example 4

[0051] The main mineral composition of the titanium ore raw material described in this embodiment is: ilmenite, ilmenite, a small amount of chromite, and trace amounts of zircon, monazite, and quartz. The titanium ore raw material contains 47.04% Fe2O3, 36.76% TiO2, and 6.35% Cr2O3, with a particle size of -0.3 mm, of which the content of -0.15 mm is about 73%.

[0052] Implementation plan in accordance with Figure 1 The following steps are shown in the diagram:

[0053] 1. Suspension magnetization roasting: Titanium ore raw material is fed into a suspension roasting furnace and mixed with reducing gas in a suspended state for reduction. The reduction temperature is 540℃, the reduction time is 10min, and the reducing gas concentration is 40% (a mixture of CO and N2 gas). After the reduction is completed, reduced roasted sand is obtained.

[0054] 2. Two-stage weak magnetic separation of iron concentrate: The feed is reduced roasted sand. First, a weak magnetic separation is carried out with a magnetic field strength of 1800 Gs to obtain a weak magnetic concentrate and a weak magnetic tailings. The weak magnetic concentrate is then subjected to a second weak magnetic separation with a magnetic field strength of 1100 Gs to obtain iron concentrate and a weak magnetic tailings.

[0055] 3. Suspension oxidation roasting: After dehydration and drying, the tailings from the first stage of magnetic separation are fed into the suspension roasting furnace and mixed with air for oxidation. The oxidation temperature is 750℃, the oxidation time is 40 minutes, and the oxidizing gas is compressed air. After oxidation, oxidized roasted sand is obtained.

[0056] 4. Magnetic separation for titanium-chromium separation: The feed ore is oxidized roasted sand, which undergoes weak magnetic separation at a field strength of 2500 Gs to obtain titanium concentrate and weakly magnetic tailings. The weakly magnetic tailings are chromium-bearing concentrate, thus achieving the separation of ilmenite and chromite. The final titanium concentrate has a TiO2 content of 46.66%, a TiO2 recovery rate of 84.16%, and a Cr2O3 content of 0.17%; the iron concentrate has a TFe grade of 61.66%, a TFe recovery rate of 27.36%, and a TiO2 content of 9.87%; and the chromium-bearing concentrate has a Cr2O3 grade of 21.65%, a TFe grade of 22.13%, and a TiO2 grade of 22.43%.

Claims

1. A method for the comprehensive utilization of titanium ore through a stepwise suspension roasting process, characterized in that, Includes the following steps: Step 1: Suspension magnetization calcination The titanium ore raw material contains 40%-50% Fe2O3, 30%-40% TiO2, and less than 10% Cr2O3. The titanium ore raw material is crushed and ground to a particle size of -0.3 mm, with 65%-80% of the particles having a particle size of -0.15 mm. It is then subjected to suspension reduction roasting, where it is mixed with a reducing gas in a suspended state to obtain reduced roasted ore. The reduction temperature is 480℃-580℃, and the reduction time is 5-60 minutes. The reducing gas is a mixture of CO and N2, with a CO concentration of 10%-60%. Step 2: Weak magnetic separation to enrich iron concentrate The reduced roasted sand is first subjected to a weak magnetic separation to obtain a weak magnetic concentrate and a weak magnetic tailings; the weak magnetic concentrate is then subjected to a second weak magnetic separation to obtain an iron concentrate and a weak magnetic tailings. Step 3: Suspension oxidation roasting The first and second weak magnetic tailings are dehydrated, dried and mixed, and then subjected to suspension oxidation roasting. They are mixed with air in a suspended state to obtain oxidized roasted sand. The oxidizing gas is compressed air. The oxidation temperature in step 3 is 600℃-1200℃ and the oxidation time is 5min-120min. Step 4: Magnetic separation to achieve titanium-chromium separation The feed is oxidized roasted sand, which is subjected to weak magnetic separation to obtain titanium concentrate and weak magnetic tailings. The weak magnetic tailings are chromium-containing concentrate, thus realizing the separation of ilmenite and chromite.

2. The method for comprehensive utilization of titanium ore through stepwise suspension roasting according to claim 1, characterized in that, The magnetic field strength of the first stage of weak magnetic separation described in step 2 is 1000Gs-2000Gs, and the magnetic field strength of the second stage of weak magnetic separation is 600Gs-1500Gs.

3. The method for comprehensive utilization of titanium ore through stepwise suspension roasting according to claim 1, characterized in that, The weak magnetic field strength mentioned in step 4 is 2000Gs-4000Gs.

4. The method for comprehensive utilization of titanium ore through stepwise suspension roasting according to claim 1, characterized in that, The iron concentrate described in step 2 has a TFe grade of 60%-63%, a TFe recovery rate of 20%-30%, and a TiO2 content of less than 12%.

5. The method for comprehensive utilization of titanium ore through stepwise suspension roasting according to claim 1, characterized in that, The titanium concentrate described in step 4 has a TiO2 content of 40%-50%, a TiO2 recovery rate of 70%-90%, and a Cr2O3 content of less than 0.2%; the chromium concentrate has a Cr2O3 grade of 20%-30%, a TFe grade of 20%-30%, and a TiO2 grade of 20%-30%.

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