CN117004817A - Suspension magnetization roasting system and method for niobium-containing magnetic separation iron concentrate - Google Patents

Abstract

The application discloses a suspension magnetization roasting system and method for niobium-containing magnetic iron concentrate, and belongs to the technical field of dressing and smelting. The suspension magnetization roasting system comprises a gas cylinder cabinet, a gas mixing box and a roasting furnace; the gas cylinder cabinet is connected with the gas mixing box; the gas mixing tank comprises a gas mixing tank, and an air outlet pipe of the gas mixing tank is connected with the roasting furnace; the furnace tube of the roasting furnace is a high-purity quartz tube, a layer of porous quartz plate is embedded in the furnace tube of the roasting furnace, and the aperture of the quartz plate is 5-15 mu m; firstly, crushing ores, carrying out low-intensity magnetic separation on the crushed ores to obtain magnetic concentrate and magnetic tailings, carrying out suspension magnetization roasting, and carrying out a separation process after fine grinding. The niobium-containing magnetic concentrate is separated by the experimental method, the index of the iron concentrate is obviously improved, and niobium is enriched in the magnetic tailings and can be further recovered.

Description

A niobium-containing magnetic separation iron concentrate suspension magnetization roasting system and method

Technical field

The invention belongs to the field of beneficiation and smelting technology, and specifically relates to a niobium-containing magnetic separation iron concentrate suspension magnetization roasting system and method.

Background technique

Niobium is a rare metal with a wide range of industrial uses. Adding a certain amount of niobium element to the metal material makes it have high temperature resistance, corrosion resistance, electrical conductivity, high ductility, etc., making it widely used in superconducting materials and the aviation industry. Thermal protection, special alloys, new energy technology, information technology, etc. A foreign niobium mine uses a combined magnetic separation and flotation process to obtain two products, niobium concentrate and iron concentrate. The Nb ₂ O ₅ content in the iron concentrate is 0.46%. It is difficult and costly to use conventional mineral processing technology to further recover niobium in iron concentrates.

Magnetization roasting is widely used in the pretreatment of complex ores and can obtain better technical indicators. At present, magnetized roasting equipment for industrial application mainly includes shaft furnaces, boiling furnaces and rotary kilns. However, there are problems such as narrow applicable range of raw material ore particle size, unstable production, low operating rate, uneven roasting and high energy consumption, and are being gradually discontinued or eliminated. The reaction method of suspension magnetization roasting is gas-solid, with a large gas-solid contact area and good reduction effect. It can make full use of waste gas for material preheating, has high energy utilization rate, and has the advantages of uniform product quality. Many domestic research units have also carried out a large amount of research on new industrial equipment and complete sets of technology for suspension magnetization roasting. The patent (CN200720014578) discloses a suspension magnetized roasting furnace; the patent (CN107460307A) discloses a comprehensive utilization system and method for suspension roasting of high-iron bauxite; the patent (CN107523685A) discloses a comprehensive utilization system of suspension roasting for iron-manganese ores and methods, the patent (CN200710012802) discloses an iron mineral suspension magnetization roasting furnace system and roasting process; the patent (CN109943710A) discloses a multi-stage suspension reduction roasting device and method for iron ore powder; the patent (CN111455165A) discloses A suspension magnetization roasting cyanide-breaking-weak magnetic separation iron extraction device for high-ferricyanide tailings has been developed. Although suspension roasting equipment and complete sets of technologies have made major technological breakthroughs in the pretreatment of complex ores and achieved efficient and comprehensive utilization of complex and refractory iron ores, suspension magnetization roasting requires a large amount of basic research on each ore sample. , its initial exploration cost is too large, which restricts its promotion progress.

Contents of the invention

In view of the problems existing in the prior art, the present invention proposes a niobium-containing magnetic separation iron concentrate suspension magnetization roasting system and method. This test method greatly reduces time, manpower and material costs.

A niobium-containing magnetic iron concentrate suspension magnetization roasting system of the present invention includes a gas bottle cabinet, a gas mixing box and a roasting furnace; the gas bottle cabinet is connected to the gas mixing box; the gas mixing box includes a gas mixing tank , the air outlet pipe of the gas mixing tank is connected to the roasting furnace;

The gas cylinder cabinet has built-in hydrogen cylinders, carbon monoxide cylinders and nitrogen cylinders; the hydrogen cylinders, carbon monoxide cylinders and nitrogen cylinders are respectively equipped with _H2 pressure reducing valves, CO pressure reducing valves and _N2 pressure reducing valves. Valve; the gas in the hydrogen cylinder, carbon monoxide cylinder and nitrogen cylinder in the gas cylinder cabinet passes through the H ₂ pressure reducing valve, CO pressure reducing valve and N ₂ pressure reducing valve respectively and then flows into the gas mixing box after being depressurized;

The air inlet pipes for hydrogen, carbon monoxide and nitrogen are all equipped with rotameter, pressure gauge and needle valve in series; the air inlet pipes for hydrogen, carbon monoxide and nitrogen are respectively connected to the gas mixing tank through air inlet quick-twist joints; The gas inside the gas mixing tank slowly passes through and mixes, and flows into the roasting furnace through the gas outlet quick-twist joint;

The furnace tube of the roasting furnace is a high-purity quartz tube. A layer of porous quartz plate is embedded inside the furnace tube of the roasting furnace. The ore particles are placed on the porous quartz plate. The aperture of the quartz plate is 5 to 15 μm; the porous quartz The gas introduced through the lower end of the furnace tube of the roasting furnace makes the ore particles suspended on the porous quartz plate for heating;

The method of the present invention for magnetic separation of niobium-containing iron concentrate with a suspension magnetization roasting system includes the following steps:

Step 1: Crush the ore;

Step 2: Conduct weak magnetic separation on the crushed ore to obtain magnetic separation concentrate and magnetic separation tailings;

Step 3 Suspension Magnetization Roasting:

(1) Place the magnetic separation tailings into the preheated roasting furnace;

(2) After nitrogen gas is introduced to replace the air in the furnace tube of the roasting furnace, reducing gas is introduced;

(3) Roast the magnetic separation tailings. After completion, turn off the reducing gas, continue to flow nitrogen, take out the quartz tube, after cooling, stop flowing nitrogen, and take out the obtained roasted material;

4. Regrinding and sorting process:

(1) Finely grind the roasted materials;

(2) Perform weak magnetic separation on the roasted materials to separate the magnetic minerals in the roasted materials.

Crush as described in step 1 until the ore particle size is -0.074mm and the content is 70-80%;

The magnetic separation concentrate described in step 2 is a rough iron ore concentrate;

The weak magnetic separation described in step 2 is carried out through a wet magnetic separator, and the magnetic field intensity is 1000~2000Oe;

The preheating temperature in step 3(1) is 500~550°C;

The reducing gas in step 3(2) is carbon monoxide and hydrogen; the order in which the reducing gas enters the gas mixing tank is to first introduce carbon monoxide and then turn on the hydrogen;

The roasting temperature in step 3(3) is 540-600°C, and the roasting time is 20-40 minutes; the reducing gas accounts for 20-60% of the total concentration of nitrogen, carbon monoxide and hydrogen;

The fine grinding described in step 4(1) is to use a three-roller and four-cylinder rod mill to grind to below 0.038mm, accounting for 85-95%;

The weak magnetic separation described in step 4(2) is carried out using a magnetic separation tube, and the magnetic field intensity is 1000~2000Oe.

The beneficial effects of the present invention are:

The invention discloses a test method for realizing suspended magnetization roasting in the laboratory. The method is simple and easy to operate, and greatly saves the cost of exploration and testing.

A gas flow meter, pressure gauge and needle regulating valve are installed for each gas in the gas mixing box. Through gas volume deployment, the industrial reducing gas atmosphere (natural gas cracking, blast furnace gas, coke oven gas and coal gas, etc.) can be simulated. The roasting temperature The amount of reducing gas and reducing gas can be precisely controlled, and the test result indicators are close to the current status of industrialization.

The niobium-containing magnetic separation concentrate is separated by this experimental method, and the iron concentrate index is significantly improved. The niobium is enriched in the magnetic separation tailings and can be further recovered.

Description of the drawings

Figure 1 is a diagram of the suspension magnetization roasting system;

Figure 2 is a structural diagram of a high-purity quartz tube, in which (a) is a plan view of the high-purity quartz tube, and (b) is a plan view of the sand core funnel in the high-purity quartz tube;

Figure 3 is a schematic structural diagram of the air mixing box;

Figure 4 is a schematic diagram of the connection of the gas mixing tank;

Figure 5 is a schematic diagram of the internal structure of the gas mixing tank;

Reference signs: 1. N ₂ pressure reducing valve, 2. H ₂ pressure reducing valve, 3. CO pressure reducing valve, 4. Nitrogen cylinder, 5. Hydrogen cylinder, 6. Carbon monoxide cylinder, 7. Gas cylinder cabinet , 8. Gas mixing box, 9. Roaster, 10. Needle valve, 11. Pressure gauge, 12. Rotameter, 13. Outlet quick-twist joint, 14. Inlet quick-twist joint, 15. Gas mixing tank.

Detailed ways

A niobium-containing magnetic separation iron concentrate suspension magnetization roasting system of the present invention, as shown in Figure 1, includes a gas bottle cabinet, a gas mixing box 8 and a roasting furnace 9; the gas bottle cabinet 7 is connected to the gas mixing box 8; The gas mixing box 8 includes a gas mixing tank 15, and the gas outlet pipe of the gas mixing tank 15 is connected to the roasting furnace 9;

The gas cylinder cabinet 7 has a built-in hydrogen cylinder 5, a carbon monoxide cylinder 6 and a nitrogen cylinder 4; the hydrogen cylinder 5, the carbon monoxide cylinder 6 and the nitrogen cylinder 4 are respectively equipped with _H2 pressure reducing valves 2, CO Pressure reducing valve 3 and N ₂ pressure reducing valve 1; the gas in the hydrogen cylinder 5, carbon monoxide cylinder 6 and nitrogen cylinder 4 in the gas cylinder cabinet 7 passes through the H ₂ pressure reducing valve 2 and CO pressure reducing valve respectively. 3 and N ₂ depressurize through the pressure reducing valve 1 and then flow into the air mixing tank 8, as shown in Figure 3;

The air inlet pipes of hydrogen, carbon monoxide and nitrogen are equipped with a rotor flowmeter 12, a pressure gauge 11 and a needle valve 10 in series; the air inlets of hydrogen, carbon monoxide and nitrogen are connected to the gas mixing tank through an air inlet quick-twist joint 14 respectively. 15 is connected, the gas inside the gas mixing tank 15 slowly passes through and is mixed, and flows into the roasting furnace 9 through the gas outlet quick-twist joint 13, as shown in Figures 4 and 5;

The furnace tube of the roasting furnace 9 is a high-purity quartz tube. As shown in Figure 2, a layer of porous quartz plate is embedded inside the furnace tube of the roasting furnace 9. The ore particles are placed on the porous quartz plate. The aperture of the quartz plate is 5 ~ 15 μm; the gas introduced into the porous quartz plate through the lower end of the furnace tube of the roasting furnace 9 causes the ore particles to be suspended on the porous quartz plate for heating;

The air intake pipe adopts 6mmPU air pipe;

In this embodiment, a disc crusher is used to further crush the ore to -0.7mm and -0.074mm content to 40-50%; 5-10kg is sampled by moving the pile and divided into parts for later use; after the ore is divided, the ore is ground to -0.074 using a conical ball mill. mm content is 70~80%;

The roasting furnace used in the embodiment of the present invention is a fluidized bed tubular furnace. The fluidized bed tubular furnace is preheated before roasting, and the preheating temperature is 500 to 550°C;

The TFe grade of the magnetically separated iron concentrate after re-selection of the niobium ore tailings in the embodiment of the present application is 65.66%, the Nb ₂ O ₅ content is 0.46%, the SiO ₂ content is 0.71%, and the CaO and MgO contents are 0.085% and 0.085% respectively. The content of Al2O3 is 0.34%, the content of Al2O3 is 1.10%, and the contents of harmful elements S and P are 0.14% and 0.17% respectively.

Example 1

A method of the present invention using the above-mentioned niobium-containing magnetic separation iron concentrate suspension magnetization roasting system includes the following steps:

1. Crushing and grinding process: Use a disc crusher to crush the ore to -0.7mm, and use a conical ball mill to further grind the ore to -0.074mm with a content of 80%.

2. Pre-selection process: Wet magnetic separator is used for weak magnetic separation operation (1620Oe), the pre-magnetic concentrate yield is 81.14%, the TFe grade is 65.66%, the Nb ₂ O ₅ content is 0.154%; the pre-magnetic tailings yield is 18.86%, TFe Grade is 55.80%, Nb ₂ O ₅ content 2.37%

3. Suspension magnetization roasting: Take 30g of pre-magnetic tailings and add it to the fluidized bed vertical tube furnace for roasting test. Through condition tests, it was determined that the roasting time was 30 minutes, the reducing atmosphere CO:H ₂ =1:3, the reducing gas concentration was 40%, and the roasting temperature was 600°C.

4. The ore is then ground into roasted products. A three-roller and four-cylinder rod mill is used to finely grind the roasted products to below 0.038mm, accounting for 93.88%. A magnetic separation tube (1650Oe) is used to separate the roasted products to obtain magnetically separated mineral concentrates. The rate is 15.41%, the TFe grade is 67.74%, and the Nb ₂ O ₅ content is 0.44%. The magnetic separation tailings yield is 1.27%, the TFe grade is 14.36%, and the Nb ₂ O ₅ content is 10.50%.

5. The niobium-containing magnetically separated iron concentrate has undergone a weak magnetic-weak magnetic tailings suspension magnetization roasting-magnetic separation test, and the TFe grade of the comprehensive iron concentrate has reached more than 67%, with a yield of 97.82% and an iron recovery rate of 99.85%; magnetic separation tailings The Nb ₂ O ₅ content in the ore is 10.50%, and the niobium recovery rate is 28.99%, achieving further enrichment of niobium.

Example 2

1. Crushing and grinding process: Use a disc crusher to crush the ore to -1mm, and use a conical ball mill to further grind the ore to -0.074mm with a content of 70%.

2. Pre-selection process: Wet magnetic separator is used for weak magnetic separation operation (1200Oe), the pre-magnetic concentrate yield is 77.75%, the TFe grade is 67.72%, the Nb ₂ O ₅ content is 0.242%; the pre-magnetic tailings yield is 22.25%, TFe The grade is 60.92% and the Nb ₂ O ₅ content is 1.16%.

3. Suspension magnetization roasting: Take 30g of pre-magnetic tailings and add it to the fluidized bed vertical tube furnace for roasting test. The roasting time was determined to be 30 minutes through condition tests, the reducing atmosphere was pure H ₂ , the reducing gas concentration was 50%, and the roasting temperature was 500°C.

4. The ore is then ground into roasted products. A three-roller and four-cylinder rod mill is used to finely grind the roasted products to less than 0.038mm, accounting for 94.67%; a magnetic separation tube (1000Oe) is used to select the roasted products to obtain magnetically separated mineral concentrates. The rate is 16.99%, the TFe grade is 67.74%, and the Nb ₂ O ₅ content is 0.157%. The magnetic separation tailings yield is 3.07%, the TFe grade is 22.62%, and the Nb ₂ O ₅ content is 8.31%.

5. The niobium-containing magnetically separated iron concentrate has undergone a weak magnetic-weak magnetic tailings suspension magnetization roasting-magnetic separation test. The TFe grade of the comprehensive iron concentrate has reached more than 67%, the yield is 94.74%, and the iron recovery rate is 99.85%; magnetic separation tailings The Nb ₂ O ₅ content in the ore is 8.31%, and the niobium recovery rate is 55.46%, achieving further enrichment of niobium.

Example 3

1. Crushing and grinding process: Use a disc crusher to crush the ore to -0.7mm, and use a conical ball mill to further grind the ore to -0.074mm with a content of 80%.

2. Pre-selection process: Wet magnetic separator is used for weak magnetic separation operation (1000Oe), the pre-magnetic concentrate yield is 75.74%, the TFe grade is 67.22%, the Nb ₂ O ₅ content is 0.213%; the pre-magnetic tailings yield is 24.26%, TFe The grade is 51.66% and the Nb ₂ O ₅ content is 1.31%.

3. Suspension magnetization roasting: Take 30g of pre-magnetic tailings and add it to the fluidized bed vertical tube furnace for roasting test. Through condition tests, it was determined that the roasting time was 20 minutes, the reducing atmosphere CO:H ₂ =1:3, the reducing gas concentration was 50%, and the roasting temperature was 600°C.

4. The ore is then ground into roasted products. A three-roller and four-cylinder rod mill is used to finely grind the roasted products to below 0.038mm, accounting for 95.48%; a magnetic separation tube (1200Oe) is used to select the roasted products to obtain magnetically separated mineral concentrates. The rate is 18.2%, the TFe grade is 67.71%, and the Nb ₂ O ₅ content is 0.59%. The magnetic separation tailings yield is 3.04%, the TFe grade is 28.97%, and the Nb ₂ O ₅ content is 6.895%.

5. The niobium-containing magnetically separated iron concentrate has undergone a weak magnetic-weak magnetic tailings suspension magnetization roasting-magnetic separation test. The TFe grade of the comprehensive iron concentrate has reached more than 67%, the yield is 93.94%, and the iron recovery rate is 96.31%; magnetic separation tailings The Nb ₂ O ₅ content in the ore is 6.893%, and the niobium recovery rate is 45.57%, achieving further enrichment of niobium.

Claims (10)

1. A suspension magnetization roasting system for niobium-containing magnetic separation iron concentrate, which is characterized in that it includes a gas bottle cabinet, a gas mixing box and a roasting furnace; the gas bottle cabinet is connected to the gas mixing box; the gas mixing box includes A gas mixing tank, the air outlet pipe of the gas mixing tank is connected to the roasting furnace. 2. The niobium-containing magnetic separation iron concentrate suspension magnetization roasting system according to claim 1, characterized in that the gas cylinder cabinet has a built-in hydrogen gas cylinder, a carbon monoxide gas cylinder and a nitrogen gas cylinder; the hydrogen gas cylinder, Carbon monoxide cylinders and nitrogen cylinders are respectively equipped with _H pressure reducing valves, CO pressure reducing valves and _N pressure reducing valves; the gases in the hydrogen cylinder, carbon monoxide cylinder and nitrogen cylinder in the gas cylinder cabinet pass through respectively The H ₂ pressure reducing valve, CO pressure reducing valve and N ₂ pressure reducing valve reduce the pressure and then flow into the mixing tank. 3. The niobium-containing magnetic separation iron concentrate suspension magnetization roasting system according to claim 2, characterized in that the air inlet pipes connected to the hydrogen cylinder, carbon monoxide cylinder and nitrogen cylinder are all equipped with rotor flowmeters in series. , pressure gauge and needle valve, and are respectively connected to the gas mixing tank through the air inlet quick-twist joint; the gas inside the gas mixing tank slowly passes through and mixes, and flows into the roasting furnace through the gas outlet quick-twist joint. 4. The niobium-containing magnetic separation iron concentrate suspension magnetization roasting system according to claim 1, characterized in that the furnace tube of the roasting furnace is a high-purity quartz tube, and a layer of porous quartz plate is embedded inside the furnace tube. , ore particles are placed on the porous quartz plate. 5. The niobium-containing magnetic separation iron concentrate suspension magnetization roasting system according to claim 4, characterized in that the aperture of the quartz plate is 5-15 μm; the porous quartz plate is passed through the lower end of the furnace tube of the roasting furnace. The gas suspends the ore particles on the porous quartz plate for heating. 6. A method of using the niobium-containing magnetic separation iron concentrate suspension magnetization roasting system according to any one of claims 1 to 5, characterized in that it includes the following steps: Step 1: Crush the ore; Step 2: Conduct weak magnetic separation on the crushed ore to obtain magnetic separation concentrate and magnetic separation tailings; Step 3 Suspension Magnetization Roasting: (1) Place the magnetic separation tailings into the preheated roasting furnace; (2) After nitrogen gas is introduced to replace the air in the furnace tube of the roasting furnace, reducing gas is introduced; (3) Roast the magnetic separation tailings. After completion, turn off the reducing gas, continue to flow nitrogen, take out the quartz tube, after cooling, stop flowing nitrogen, and take out the obtained roasted material; 4. Regrinding and sorting process: (1) Finely grind the roasted materials; (2) Perform weak magnetic separation on the roasted materials to separate the magnetic minerals in the roasted materials. 7. The method for magnetic separation of niobium-containing iron concentrate in a suspension magnetization roasting system according to claim 6, characterized in that in step 1, the ore is crushed until the particle size is -0.074 mm and the content is between 70 and 80%. 8. The method for the suspension magnetization roasting system of niobium-containing magnetic separation iron concentrate according to claim 6, characterized in that the magnetic separation concentrate in step 2 is a rough iron ore concentrate; and the weak magnetic separation is It is carried out through a wet magnetic separator, and the magnetic field intensity is 1000~2000Oe. 9. The method of niobium-containing magnetic separation iron concentrate suspension magnetization roasting system according to claim 6, characterized in that the preheating temperature in step 3 (1) is 500-550°C; and the preheating temperature in step 3 (2) The reducing gas is carbon monoxide and hydrogen; the order in which the reducing gas enters the gas mixing tank is to first introduce carbon monoxide and then turn on the hydrogen; the roasting temperature in step 3 (3) is 540-600°C, and the roasting time is 20-40 minutes; Reducing gas accounts for 20 to 60% of the total concentration of nitrogen, carbon monoxide and hydrogen. 10. The method of niobium-containing magnetic separation iron concentrate suspension magnetization roasting system according to claim 6, characterized in that the fine grinding in step 4 (1) is to use a three-roller and four-cylinder rod mill to grind to 0.038 mm and below account for 85-95%; the weak magnetic separation described in step 4 (2) is carried out using a magnetic selection tube, and the magnetic field intensity is 1000-2000Oe.