Process for reducing and magnetizing refractory iron ore at low temperature through plasma hydrogen

Abstract

The invention discloses a process for reducing and magnetizing refractory iron ore at low temperature by plasma hydrogen, which comprises the following steps of: carrying out coarse crushing, high-pressure roller milling and screening on an iron ore raw material in sequence to obtain raw iron ore with the particle size of less than 3mm; the method comprises the following steps: carrying out plasma hydrogen reduction magnetization treatment on raw iron ore by adopting a plasma hydrogen reactor to obtain a magnetized product; the magnetized product is subjected to ore grinding and then subjected to low-intensity magnetic separation, and low-intensity magnetic concentrate and low-intensity magnetic tailings are obtained; the weak magnetic tailings are subjected to strong magnetic separation, and strong magnetic concentrate and strong magnetic tailings are obtained; and the weak magnetic concentrate and the strong magnetic concentrate are mixed, and final concentrate is obtained. The beneficiation method of the plasma hydrogen reduction magnetization technology is adopted for the first time, surface magnetization of the refractory iron ore is achieved, and therefore the new technology of iron recovery is achieved, the reduction time and the reduction temperature of a traditional roasting reduction magnetization technology are greatly shortened, and the development utilization rate of the low-grade iron ore and the economic benefits of the separation machining process can be remarkably increased; the low-carbon development of the steel industry is promoted.

Description

Technical Field

[0001] The invention relates to the technical field of materials and metallurgy, and more specifically, to a plasma hydrogen low-temperature reduction magnetization process for refractory iron ore. Background Art

[0002] Iron ore is an important mineral resource that is indispensable to the development of human society. With the increasing depletion of high-quality iron ore resources, the development of low-grade and complex and difficult-to-select iron ore resources has become a research direction with economic and strategic significance. Magnetic separation is a process that uses the difference in magnetic strength between minerals and impurities for separation, and is one of the main processes for iron ore separation and processing. Low-grade, complex and difficult-to-select iron ore generally includes fine-grained hematite, oolitic hematite, specularite, limonite and siderite. Because they are weakly magnetic minerals, it is difficult to effectively separate them using traditional separation methods. In conventional iron ore beneficiation production, the mixing of low-grade and difficult-to-select iron ore resources will also cause problems such as poor economic benefits of separation, low resource recovery and utilization, and environmental pollution caused by tailings.

[0003] Improving the separation characteristics of low-grade and difficult-to-select iron ore through effective magnetization pretreatment is an important method to improve the utilization rate of this type of resources. However, the existing magnetization roasting process has problems such as high reaction temperature, long time, high energy consumption, and poor economic benefits. In the face of increasing pressure to reduce carbon emissions, how to promote the magnetization efficiency in the hydrogen reduction process and reduce the reaction temperature and reaction time is an effective way to effectively solve the problem of low-grade, complex and difficult-to-select iron ore development and utilization value. Summary of the invention

[0004] The purpose of the present invention is to overcome the above-mentioned defects of the prior art and provide a plasma hydrogen low-temperature reduction magnetization process for refractory iron ore. By utilizing plasma hydrogen reduction magnetization for low-grade refractory iron ore, the magnetization reaction temperature and reaction time can be significantly shortened, and the production cost can be significantly reduced.

[0005] To achieve the above object, the technical solution of the present invention is as follows:

[0006] A plasma hydrogen low-temperature reduction magnetization process for refractory iron ore comprises the following steps:

[0007] (1) The iron ore raw material is subjected to coarse crushing, high pressure roller grinding and screening in sequence to obtain iron ore raw ore with a particle size of less than 3 mm;

[0008] (2) subjecting the raw iron ore to plasma hydrogen reduction magnetization treatment in a plasma hydrogen reactor to obtain a magnetized product;

[0009] (3) grinding the magnetized product and performing weak magnetic separation to obtain weak magnetic concentrate and weak magnetic tailings;

[0010] (4) subjecting the weak magnetic tailings to strong magnetic separation to obtain strong magnetic concentrate and strong magnetic tailings;

[0011] (5) Mixing the weak magnetic concentrate and the strong magnetic concentrate to obtain a final concentrate.

[0012] Optionally, in step (2), the plasma hydrogen reduction magnetization treatment specifically includes the following steps: placing the raw iron ore into the plasma hydrogen reactor, evacuating the reactor and then inputting a mixture of inert gas and active gas, performing plasma hydrogen reduction magnetization treatment under the action of plasma to obtain a magnetized product.

[0013] Optionally, the inert gas includes at least one of N2 and Ar2.

[0014] Optionally, the active gas is H2.

[0015] Optionally, the volume concentration ratio of the inert gas to the active gas is 3:97 to 20:80.

[0016] Optionally, the voltage of the plasma hydrogen reduction magnetization treatment is 60V~220V, preferably 80V; the current of the plasma hydrogen reduction magnetization treatment is 240A~400A, preferably 240A; the time of the plasma hydrogen reduction magnetization treatment is 30s~5min; the reaction gas pressure of the plasma hydrogen reduction magnetization treatment is 0.1Mpa~2Mpa; the reaction temperature of the plasma hydrogen reduction magnetization treatment is 20℃~500℃.

[0017] Optionally, the plasma includes at least one of glow discharge plasma, dielectric barrier plasma, radio frequency plasma and tip discharge plasma.

[0018] Optionally, the plasma hydrogen reactor includes at least one of a static furnace generator, a static tubular generator, a dynamic tubular reactor and a suspended furnace generator.

[0019] Optionally, in step (1), the iron ore raw material includes iron ore raw material with an iron grade of 15% to 25%.

[0020] Optionally, the iron ore raw material includes one or more of fine-grained hematite, oolitic hematite, specularite, limonite and siderite.

[0021] Optionally, in step (3), the magnetic field strength of the weak magnetic separation is 80kA / m to 160kA / m.

[0022] Optionally, in step (4), the magnetic strength of the strong magnetic separation is 800kA / m to 1200kA / m.

[0023] Optionally, the iron grade of the final concentrate is ≥62%, and the total recovery rate of iron is ≥80%.

[0024] Implementing the embodiments of the present invention will have the following beneficial effects:

[0025] The present invention provides for the first time a mineral processing method using plasma hydrogen reduction magnetization technology to achieve surface magnetization of difficult-to-select iron ore, thereby carrying out a new process for iron recovery, greatly reducing the reduction time and reduction temperature of the traditional roasting reduction magnetization process, significantly improving the development and utilization rate of low-grade iron ore and the economic benefits of the sorting and processing process, and promoting the low-carbon development of the steel industry.

[0026] The invention has a wide range of applications, and is applicable to various iron ores and low-grade, difficult-to-select iron ore raw materials. The roasted product has strong magnetism, and can greatly improve the separation efficiency of subsequent magnetic separation processes.

[0027] The present invention significantly shortens the existing mineral processing process and has excellent mineral processing indicators. The magnetic properties of the iron ore are improved after magnetization treatment, thereby greatly improving the separation efficiency of the subsequent magnetic separation process. The final concentrate product has an iron grade of more than 62% and an iron recovery rate of more than 80%, thereby maximizing the utilization efficiency of iron ore resources and improving economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a process flow chart of the plasma hydrogen low-temperature reduction magnetization of refractory iron ore of the present invention. DETAILED DESCRIPTION

[0029] The present invention is further described below in conjunction with specific embodiments, but the present invention is not limited in any way. The present invention discloses a plasma hydrogen low-temperature reduction magnetization refractory iron ore process, comprising the following steps:

[0030] (1) The iron ore raw material is subjected to coarse crushing, high pressure roller grinding and screening in sequence to obtain iron ore with a particle size of less than 3 mm.

[0031] In a specific embodiment, the iron ore raw material includes an iron ore raw material with an iron grade of 15% to 25%; the iron ore raw material includes one or more of fine-grained hematite, oolitic hematite, specularite, limonite and siderite.

[0032] (2) The raw iron ore is subjected to plasma hydrogen reduction magnetization treatment using a plasma hydrogen reactor to obtain a magnetized product.

[0033] In a specific embodiment, the plasma hydrogen reduction magnetization treatment specifically includes the following steps: placing the raw iron ore into a plasma hydrogen reactor, evacuating the reactor and then inputting a mixture of inert gas and active gas, performing plasma hydrogen reduction magnetization treatment under the action of plasma to obtain a magnetized product.

[0034] In a specific embodiment, the inert gas includes N2 and / or Ar2; the active gas is H2; and the volume concentration ratio of the inert gas to the active gas is 3:97 to 20:80.

[0035] In a specific embodiment, the voltage of the plasma hydrogen reduction magnetization treatment is 60V~220V; the current of the plasma hydrogen reduction magnetization treatment is 240A~400A; the time of the plasma hydrogen reduction magnetization treatment is 30s~5min; the reaction gas pressure of the plasma hydrogen reduction magnetization treatment is 0.1Mpa~2Mpa; the reaction temperature of the plasma hydrogen reduction magnetization treatment is 20℃~500℃.

[0036] In a specific embodiment, the plasma includes at least one of glow discharge plasma, dielectric barrier plasma, radio frequency plasma, and tip discharge plasma.

[0037] In a specific embodiment, the plasma hydrogen reactor includes at least one of a static furnace generator, a static tube generator, a dynamic tube reactor, and a suspended furnace generator.

[0038] (3) The magnetized product is ground and then subjected to weak magnetic separation to obtain weak magnetic concentrate and weak magnetic tailings.

[0039] In a specific embodiment, the magnetic field strength of the weak magnetic separation is 80 kA / m to 160 kA / m, preferably 90 kA / m.

[0040] (4) The weak magnetic tailings are subjected to strong magnetic separation to obtain strong magnetic concentrate and strong magnetic tailings.

[0041] In a specific embodiment, the magnetic strength of the strong magnetic separation is 800 kA / m to 1200 kA / m, preferably 800 kA / m.

[0042] (5) Mix the weak magnetic concentrate and the strong magnetic concentrate to obtain a final concentrate.

[0043] In a specific embodiment, the iron grade of the final concentrate is ≥62%, and the total recovery rate of iron is ≥80%.

[0044] The following are specific embodiments

[0045] Example 1

[0046] The plasma hydrogen low-temperature reduction magnetization process for refractory iron ore of this embodiment comprises the following steps:

[0047] (1) The test ore sample is a low-grade hematite ore with an iron grade of 26.57%, an original ore particle size of 200 mm, and a main gangue mineral quartz content of 37.68%. The ore is then subjected to coarse crushing, high-pressure roller milling, and vibrating screen screening in sequence to obtain a narrow grade material with a particle size of 0.5 mm to 3 mm.

[0048] (2) The narrow grade material obtained in step (1) is placed in a glow discharge plasma hydrogen reactor, and after vacuuming, a mixture of an inert gas and an active gas is input, wherein the inert gas is N2. The active gas is H2 with a concentration of 10%, and the volume concentration ratio of the inert gas to the active gas is 5:4. Plasma hydrogen reduction magnetization treatment is carried out under the action of plasma, and the magnetite content is increased from 25% to 45%, and a magnetized product is obtained. Among them, the voltage of the plasma hydrogen reduction magnetization treatment is 80V; the current of the plasma hydrogen reduction magnetization treatment is 260A; the time of the plasma hydrogen reduction magnetization treatment is 2min; the reaction gas pressure of the plasma hydrogen reduction magnetization treatment is 0.1Mpa; and the reaction temperature of the plasma hydrogen reduction magnetization treatment is 100°C.

[0049] (3) The magnetized product is ground and then subjected to weak magnetic separation with a field strength of 100 kA / m to obtain weak magnetic concentrate and weak magnetic tailings.

[0050] (4) The weak magnetic tailings are subjected to strong magnetic separation with a field strength of 900 kA / m to obtain strong magnetic concentrate and strong magnetic tailings.

[0051] (5) The weak magnetic concentrate and the strong magnetic concentrate are mixed to obtain a final concentrate with an iron grade of 62.56% and a total iron recovery rate of 86.41%.

[0052] Example 2

[0053] The plasma hydrogen low-temperature reduction magnetization process for refractory iron ore of this embodiment comprises the following steps:

[0054] (1) The test ore sample selected in this embodiment is different from that in Example 1 only in that the iron grade in the raw ore is 31.23%, the siderite content accounts for 8.12%, and then it is subjected to coarse crushing, high-pressure roller milling and vibrating screen screening in sequence to obtain a narrow grade material with a particle size of 0.5 mm to 1 mm.

[0055] (2) The narrow grade material obtained in step (1) is placed in a dielectric barrier plasma plasma hydrogen reactor, and after vacuuming, a mixture of an inert gas and an active gas is input, wherein the inert gas is N2. The active gas is H2 with a concentration of 20%, and the volume concentration ratio of the inert gas to the active gas is 9:1. Plasma hydrogen reduction magnetization treatment is carried out under the action of plasma, and the magnetite content is increased from 15% to 30%, and a magnetized product is obtained. Among them, the voltage of the plasma hydrogen reduction magnetization treatment is 150V; the current of the plasma hydrogen reduction magnetization treatment is 300A; the time of the plasma hydrogen reduction magnetization treatment is 3min; the reaction gas pressure of the plasma hydrogen reduction magnetization treatment is 0.2Mpa; and the reaction temperature of the plasma hydrogen reduction magnetization treatment is 200℃.

[0056] (3) The magnetized product is ground and then subjected to weak magnetic separation with a field strength of 140 kA / m to obtain weak magnetic concentrate and weak magnetic tailings.

[0057] (4) The weak magnetic tailings are subjected to strong magnetic separation with a field strength of 1200 kA / m to obtain strong magnetic concentrate and strong magnetic tailings.

[0058] (5) The weak magnetic concentrate and the strong magnetic concentrate are mixed to obtain a final concentrate with an iron grade of 63.32% and a total iron recovery rate of 86.41%.

[0059] Example 3

[0060] The plasma hydrogen low-temperature reduction magnetization process for refractory iron ore of this embodiment comprises the following steps:

[0061] (1) The test ore sample selected in this embodiment is different from that in Example 1 only in that the iron grade in the raw ore is 34.56%, and the iron minerals are mainly fine-grained hematite. Subsequently, the raw ore is subjected to coarse crushing, high-pressure roller milling and vibrating screen screening in sequence to obtain a narrow grade material with a particle size of 0.5 mm to 2 mm.

[0062] (2) The narrow grade material obtained in step (1) is placed in a radio frequency plasma hydrogen reactor, and after vacuuming, a mixture of an inert gas and an active gas is input, wherein the inert gas is Ar2, the active gas is H2 with a concentration of 8%, and the volume concentration ratio of the inert gas to the active gas is 7:3, and plasma hydrogen reduction magnetization treatment is carried out under the action of plasma, and the magnetite content is increased from 25% to 50%, and a magnetized product is obtained. Among them, the voltage of the plasma hydrogen reduction magnetization treatment is 180v; the current of the plasma hydrogen reduction magnetization treatment is 360A; the time of the plasma hydrogen reduction magnetization treatment is 2min; the reaction gas pressure of the plasma hydrogen reduction magnetization treatment is 0.2Mpa; and the reaction temperature of the plasma hydrogen reduction magnetization treatment is 50°C.

[0063] (3) The magnetized product is ground and then subjected to weak magnetic separation with a field strength of 360 kA / m to obtain weak magnetic concentrate and weak magnetic tailings.

[0064] (4) The weak magnetic tailings are subjected to strong magnetic separation with a field strength of 1000 kA / m to obtain strong magnetic concentrate and strong magnetic tailings.

[0065] (5) The weak magnetic concentrate and the strong magnetic concentrate are mixed to obtain a final concentrate with an iron grade of 62.86% and a total iron recovery rate of 83.41%.

[0066] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A plasma hydrogen low temperature reduction magnetization process for refractory iron ore, characterized in that: The following steps are involved: (1) The iron ore raw material is subjected to coarse crushing, high pressure roller grinding and screening in sequence to obtain iron ore raw ore with a particle size of less than 3 mm; (2) subjecting the raw iron ore to plasma hydrogen reduction magnetization treatment in a plasma hydrogen reactor to obtain a magnetized product; (3) grinding the magnetized product and performing weak magnetic separation to obtain weak magnetic concentrate and weak magnetic tailings; (4) subjecting the weak magnetic tailings to strong magnetic separation to obtain strong magnetic concentrate and strong magnetic tailings; (5) Mixing the weak magnetic concentrate and the strong magnetic concentrate to obtain a final concentrate.

2. The plasma hydrogen low temperature reduction magnetization refractory iron ore process according to claim 1 is characterized in that: In step (2), the plasma hydrogen reduction magnetization treatment specifically comprises the following steps: The raw iron ore is placed in the plasma hydrogen reactor, and after evacuation, a mixed gas of an inert gas and an active gas is introduced, and a plasma hydrogen reduction magnetization treatment is performed under the action of plasma to obtain a magnetized product.

3. The plasma hydrogen low temperature reduction magnetization refractory iron ore process according to claim 2 is characterized in that: The inert gas includes at least one of N2 and Ar2; The active gas is H2; The volume concentration ratio of the inert gas to the active gas is 3:97 to 20:

80.

4. The plasma hydrogen low temperature reduction magnetization refractory iron ore process according to claim 2 is characterized in that: The voltage of the plasma hydrogen reduction magnetization treatment is 60V to 220V; The current of the plasma hydrogen reduction magnetization treatment is 240A to 400A; The plasma hydrogen reduction magnetization treatment lasts for 30 seconds to 5 minutes; The reaction gas pressure of the plasma hydrogen reduction magnetization treatment is 0.1Mpa to 2Mpa; The reaction temperature of the plasma hydrogen reduction magnetization treatment is 20°C to 500°C; The plasma includes at least one of glow discharge plasma, dielectric barrier plasma, radio frequency plasma and tip discharge plasma; The plasma hydrogen reactor includes at least one of a static furnace generator, a static tube generator, a dynamic tube reactor and a suspended furnace generator.

5. The plasma hydrogen low temperature reduction magnetization refractory iron ore process according to claim 1 is characterized in that: In step (1), the iron ore raw material includes an iron ore raw material with an iron grade of 15% to 25%; The iron ore raw material includes one or more of fine-grained hematite, oolitic hematite, specularite, limonite and siderite.

6. The plasma hydrogen low temperature reduction magnetization refractory iron ore process according to claim 1, characterized in that: In step (3), the magnetic field strength of the weak magnetic separation is 80kA / m to 160kA / m.

7. The plasma hydrogen low temperature reduction magnetization refractory iron ore process according to claim 1 is characterized in that: In step (4), the magnetic intensity of the strong magnetic separation is 800kA / m to 1200kA / m.

8. The plasma hydrogen low temperature reduction magnetization refractory iron ore process according to claim 1, characterized in that: The iron grade of the final concentrate is ≥62%, and the total recovery rate of iron is ≥80%.

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