Siderite treatment method and equipment

Abstract

The invention discloses a siderite treatment method. The siderite treatment method comprises the steps that S1, siderite lump ore is conveyed to a belt type pellet roasting machine; s2, carrying out dehydration treatment on the siderite lump ore; s3, carrying out pre-oxidation treatment on the siderite lump ore; s4, carrying out oxidizing roasting treatment on the siderite lump ore; s5, the siderite lump ore is subjected to soaking treatment; and S6, cooling treatment is conducted on the siderite lump ore. According to the siderite treatment method, efficient treatment and utilization of siderite lump ore can be achieved, the ore quality is improved, and more optional lump ore resources are provided for blast furnace or converter smelting. The invention further discloses siderite treatment equipment.

Description

Technical Field

[0001] The invention belongs to the technical field of pelletizing, and in particular relates to a siderite processing method and equipment. Background Art

[0002] Lump ore is a common raw material for blast furnaces or converters. Since lump ore has a higher economic smelting value than sintered ore and pelletized ore, it is crucial for green low-carbon and low-cost smelting. Natural lump ore resources are relatively scarce, and high-quality lump ore is even more scarce, which is basically controlled by overseas mining giants. Siderite has not been effectively utilized due to its low grade, high impurity content, and large burning loss.

[0003] In recent years, with the increasing attention paid to siderite resources, siderite development and utilization technologies have emerged continuously, but they all have certain shortcomings or limitations. There are several methods for siderite processing:

[0004] Belt sintering machine processing method: crush the siderite and coal (particle size <1mm) and put them into the silo respectively, stir and mix them in the mixer, and transport them to the belt sintering machine for roasting; the roasted siderite is crushed in the crushing device and put into the clinker site.

[0005] Chain grate-rotary kiln processing method: the siderite ore is crushed and screened, and then added to the chain grate-rotary kiln for reduction roasting. The reduced roasted ore is then screened and dry-magnetically separated to obtain magnetic products and non-magnetic products. The two products are then crushed, ground, magnetically separated, and wind-sorted, and the products are direct reduced iron powder and cement raw materials, etc.

[0006] Rotary hearth furnace combined grinding and magnetic separation treatment method: the siderite is finely ground into balls, and dry pellets are obtained; the dry pellets are sent to a rotary hearth furnace, first subjected to magnetic roasting, and then reduced by adding a reducing agent for reduction roasting to obtain metallized pellets, and the metallized pellets are water quenched, then ground and magnetically separated to obtain iron concentrate.

[0007] Vertical furnace roasting method: Siderite is added from the vertical furnace pellet bin, reaches the vertical furnace via the pellet belt, and is discharged from the vertical furnace after oxidation roasting.

[0008] From the above we can see that:

[0009] (1) Since siderite decomposes and explodes when heated, the belt sintering machine process roasts siderite with a particle size of less than 1 cm. The finished ore is then affected by the transport process. The resulting siderite is difficult to meet the technical requirements of the blast furnace or converter for lump ore (generally requiring +8mm>90%) in terms of particle size and can only be used as powder ore or for other purposes.

[0010] (2) Chain grate-rotary kiln and rotary hearth furnace combined grinding and magnetic separation treatment method, the products obtained are direct reduced iron powder and iron concentrate, which cannot be used as lump ore in blast furnace or converter.

[0011] (3) Due to the uneven distribution of temperature and atmosphere in the vertical furnace, or due to the incomplete oxidation and roasting of siderite, the product strength is poor and the impurities are not completely removed; or due to over-roasting, the product explodes and breaks seriously. In short, the quality of the products obtained by the vertical furnace process varies greatly and fluctuates greatly.

[0012] It is hoped to provide an improved siderite processing method and equipment, especially regarding how to efficiently develop and utilize siderite resources to provide high-quality lump ore for blast furnaces or converters. Summary of the invention

[0013] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides a siderite processing method, the purpose of which is to achieve efficient processing of siderite and improve its quality.

[0014] In order to achieve the above object, the technical solution adopted by the present invention is: a siderite processing method, comprising the steps of:

[0015] S1, conveying the siderite lump ore to the belt pellet roaster;

[0016] S2, dehydrating the siderite lump;

[0017] S3, pre-oxidation treatment of the siderite lump ore;

[0018] S4, oxidizing and roasting the siderite lump;

[0019] S5, performing a heat treatment on the siderite lump;

[0020] S6. Cooling the siderite lump.

[0021] The step S2 comprises:

[0022] S201, preliminarily drying the siderite lump ore;

[0023] S202, secondary drying of the siderite lump ore.

[0024] The belt pellet roasting machine comprises a blast drying section, an exhaust drying section, a preheating section, a roasting section, a soaking section and a cooling section which are arranged in sequence; in the blast drying section, the siderite lumps are preliminarily dried; in the exhaust drying section, the siderite lumps are secondary dried.

[0025] The hot air generated in the cooling section is sent to the blast drying section through the blast drying induced draft fan.

[0026] The waste gas generated in the soaking section and / or the roasting section is sent to the exhaust drying section through a heat recovery fan.

[0027] The waste gas generated in the soaking section and / or the roasting section is sent to the preheating section through a heat recovery fan.

[0028] The step S6 comprises:

[0029] S601, cooling the siderite lump ore for the first time;

[0030] S602, cooling the siderite lump ore for a second time.

[0031] The cooling section includes a cooling section I and a cooling section II. In the cooling section I, the siderite lump is cooled for the first time; and in the cooling section II, the siderite lump is cooled for the second time.

[0032] The particle size of the siderite lump ore is between 8 mm and 40 mm.

[0033] The invention provides a siderite processing device, which is used in the siderite processing method.

[0034] The siderite processing method of the present invention can realize the efficient processing and utilization of siderite lump ore, improve the ore quality, and provide more optional lump ore resources for blast furnace or converter smelting. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] This specification includes the following drawings, which show the following contents:

[0036] Figure 1 is a flow chart of the siderite processing method of the present invention;

[0037] Figure 2 It is a structural schematic diagram of the siderite processing equipment of the present invention;

[0038] The markings in the figure are: 1. First conveying mechanism; 2. Bottom material bin; 3. Blast drying section; 4. Exhaust drying section; 5. Preheating section; 6. Roasting section; 7. Soaking section; 8. I cooling section; 9. II cooling section; 10. Direct heat recovery pipeline; 11. Second conveying mechanism; 12. Finished product warehouse yard; 13. Trolley (belt roasting machine); 14. Cooling fan; 15. Heat recovery fan; 16. Main exhaust fan; 17. Blast drying induced draft fan; 18. Furnace hood fan. DETAILED DESCRIPTION

[0039] The specific implementation methods of the present invention are further explained in detail below by describing the embodiments with reference to the accompanying drawings, with the aim of helping those skilled in the art to have a more complete, accurate and in-depth understanding of the inventive concept and technical solution of the present invention and facilitating their implementation.

[0040] It should be noted that, in the following embodiments, the “first” and “second” mentioned do not represent an absolute distinction in structure and / or function, nor do they represent a sequential order of execution, but are merely for the convenience of description.

[0041] like Figure 1 As shown, the present invention provides a siderite processing method, characterized in that it includes the following steps:

[0042] S1, conveying the siderite lump ore to the belt pellet roaster;

[0043] S2, dehydrating the siderite lump;

[0044] S3, pre-oxidation treatment of the siderite lump ore;

[0045] S4, oxidizing and roasting the siderite lump;

[0046] S5, performing a heat treatment on the siderite lump;

[0047] S6. Cooling the siderite lump.

[0048] Specifically, the rich siderite resources in China have not been effectively utilized due to low grade, high impurity content, large burning loss, etc. In the present invention, by roasting the siderite lump ore, the TFe grade is increased, the S (sulfur) content is reduced, and the smelting performance is improved, which will have obvious resource advantages and safety guarantees, thereby providing more guarantees for the long-term and stable development of the steel industry.

[0049] In the above step S1, the particle size of the siderite lump is between 8 mm and 40 mm, and the screened siderite lump is transported from the silo to the bottom silo 2 of the belt pellet roaster through the first conveying mechanism 1. The siderite lump flows out of the bottom silo 2 continuously and is evenly spread on the moving belt pellet roaster.

[0050] like Figure 2 As shown, the belt pellet roaster includes a blast drying section 3, an exhaust drying section 4, a preheating section 5, a roasting section 6, a soaking section 7 and a cooling section which are arranged in sequence. In the blast drying section 3, the siderite ore lump is preliminarily dried. In the exhaust drying section 4, the siderite ore lump is secondary dried. In the preheating section 5, the siderite ore lump is pre-oxidized. In the roasting section 6, the siderite ore lump is roasted. In the soaking section 7, the siderite ore lump is soaked. In the cooling section, the siderite ore lump is cooled.

[0051] After the siderite lump ore has completed dehydration, pre-oxidation, oxidation roasting, soaking and cooling treatment in sequence, it is discharged from the belt pellet roasting machine and enters the finished product warehouse or yard.

[0052] The above step S2 comprises:

[0053] S201, preliminarily drying the siderite lump ore;

[0054] S202, secondary drying of the siderite lump ore.

[0055] In the above step S201, the siderite lump enters the blast drying section 3, where the siderite lump is preliminarily dried. By introducing hot air of a certain temperature (the hot air temperature is 270-310° C.) into the blast drying section 3, the physical water on the surface of the siderite lump is removed, and at the same time, the lower siderite lump is prevented from being over-humidified and deformed and cracked under pressure. The drying effect at this stage is crucial for the subsequent process steps.

[0056] In the above step S202, the siderite lump ore that has completed the preliminary drying enters the exhaust drying section 4, where the siderite lump ore is dried again. The exhaust drying section 4 is a further drying stage after the blast drying section 3. It uses hot exhaust gas (hot exhaust gas temperature is 370-385°C) to deeply dry the siderite lump ore layer, so that the siderite lump ore is further dehydrated and dried, and its adaptability to the subsequent high temperature environment is enhanced.

[0057] In the above step S3, the high-temperature flue gas generated by the combustion of the coke oven gas in the belt pellet roaster is ejected from the furnace through the siderite material layer to pre-oxidize the siderite lump. The pre-oxidation treatment of the siderite lump mainly involves the valence change of the iron element in the siderite and the accompanying chemical reaction. The purpose of the pre-oxidation treatment is to oxidize the ferrous ions in the siderite into trivalent ferrous ions, thereby changing the physical and chemical properties of the siderite, such as magnetism and chemical activity, so as to facilitate subsequent mineral processing, smelting or other applications.

[0058] In the above step S4, the high-temperature flue gas generated by the combustion of the coke oven gas in the belt pellet roaster is ejected from the furnace through the siderite material layer, and the siderite lump ore that has completed the pre-oxidation treatment is subjected to oxidation roasting treatment. The oxidation roasting treatment mainly utilizes the oxidation reaction at high temperature to change the chemical state and mineral phase composition of the iron oxide in the siderite. At high temperature, the iron oxide in the siderite reacts with the oxygen in the air to generate more stable, easier to separate and purify iron oxide. At the same time, other chemical reactions may also occur during the roasting process, such as oxidation and decomposition of impurities in the ore material, which help to further improve the purity and utilization value of the ore material and help to improve the quality of the ore.

[0059] In the above step S5, the high-temperature flue gas generated by the combustion of the coke oven gas in the belt pellet roaster is ejected from the furnace through the siderite material layer to perform a heat treatment on the siderite lumps that have completed the oxidation roasting treatment, so that the siderite lumps are evenly heated.

[0060] The above step S6 comprises:

[0061] S601, cooling the siderite lump ore for the first time;

[0062] S602, cooling the siderite lump ore for a second time.

[0063] like Figure 2 As shown, the cooling section includes a cooling section I 8 and a cooling section II 9 which are arranged in sequence, and the cooling section I 8 is located between the cooling section II 9 and the soaking section 7. In the above step S601, the siderite lump is cooled for the first time in the cooling section I 8. In the above step S602, the siderite lump which has completed the first cooling is cooled for the second time in the cooling section II 9.

[0064] In the above step S601, ambient air is sucked in by the cooling fan 14 and sent into the cooling section 8 to perform the first cooling on the siderite lump.

[0065] In the above step S602, ambient air is sucked in by the cooling fan 14 and sent into the II cooling section 9 to perform a second cooling on the siderite lump.

[0066] Two cooling steps are set up to recycle the hot exhaust gas from the two cooling steps, which has a better energy-saving effect. The hot air from the I cooling section 8 enters the equalizing, roasting and preheating sections as combustion-supporting gas through the direct recuperation principle, and the hot air from the II cooling section 9 is sent to the blast drying section for use through the blast drying induced draft fan.

[0067] As a preferred example, Figure 2 As shown, the hot air generated by the I cooling section 8 enters the equalizing section 7, the roasting section 6 and the preheating section 5 respectively through the direct heat recovery pipeline 10. The direct recuperation heat exchange principle is adopted. The hot air from the I cooling section 8 enters the equalizing section 7, the roasting section 6 and the preheating section 5, and can be used as a combustion-supporting gas, thereby achieving energy-saving effects.

[0068] As a preferred example, Figure 2 As shown, the hot air generated by the II cooling section 9 is sent to the blast drying section 3 through the blast drying induced draft fan 17, and is used to dry the siderite lumps in the blast drying section 3, thereby achieving energy saving effect.

[0069] As a preferred example, Figure 2 As shown, the exhaust gas generated by the soaking section 7 and the roasting section 6 is sent to the exhaust drying section 4 through the heat recovery fan 15. The exhaust drying section 4 uses the hot exhaust gas from the soaking section 7 and the roasting section 6 to deeply dry the siderite block material layer, which can achieve energy saving effect.

[0070] As a preferred example, Figure 2As shown, the exhaust gas generated in the soaking section 7 and the roasting section 6 is sent to the preheating section 5 through the heat recovery fan 15, and is used to pre-oxidize the siderite lumps in the preheating section 5, thereby achieving energy-saving effect.

[0071] As a preferred example, Figure 2 As shown, the waste gas generated by the forced air drying section 3 is purified by the bag filter in the furnace cover and then discharged into the atmosphere. The waste gas generated by the exhaust drying section 4 and the preheating section 5 first passes through the main exhaust electrostatic precipitator, enters the desulfurization and denitrification system, and is discharged into the atmosphere through the chimney after purification.

[0072] like Figure 2 As shown, the present invention also provides a siderite processing device for use in the above-mentioned siderite processing method. The belt-type pellet roasting machine of the present invention mainly includes a blast drying section 3, an exhaust drying section 4, a preheating section 5, a roasting section 6, a soaking section 7 and a cooling section which are arranged in sequence. The belt-type pellet roasting machine adopts an advanced air flow process system to ensure energy saving effect.

[0073] The belt pellet roaster is equipped with special gas burners, which are arranged symmetrically on both sides. Each burner is equipped with an automatic adjustment device to adjust the temperature.

[0074] like Figure 2 As shown, the belt pellet roasting machine is equipped with a cooling fan 14, a heat recovery fan 15, a blast drying induced draft fan 17, a furnace hood fan 18 and a main exhaust fan 16, and the main exhaust fan 16 is connected to the exhaust drying section 4, the preheating section 5 and the roasting section 6.

[0075] The siderite processing method and equipment of the present invention have the following advantages:

[0076] 1. It has the advantages of advanced technology, good roasting effect, large single machine processing capacity, high heat utilization rate, low energy consumption and processing cost, etc.

[0077] 2. Siderite decomposes under heat to release CO2, and the sulfur contained in it is effectively removed through oxidation. This process uses coke oven gas as fuel, and completes the drying, preheating, roasting, soaking and cooling on one device. Each process section can be operated separately, which is convenient for precise control.

[0078] 3. The production process is completed on a sealed device. The waste gas heat recovered in the high-temperature section is circulated for use in the low-temperature section, with high efficiency in heat utilization and heat recovery.

[0079] 4. The temperature and airflow are distributed evenly, and the product quality difference is small. The single machine has large processing capacity and high production efficiency.

[0080] 5. Compared with the original ore, the obtained product has more thorough oxidation and decomposition of siderite and removal of S, and the product has high TFe content, low S content and good metallurgical properties. After screening or processing, the +8mm product can be used in blast furnaces or converters, and the -8mm product can be used for sintering.

[0081] Example

[0082] This embodiment discloses a method for roasting siderite in a belt pellet roaster, which specifically includes the following implementation steps:

[0083] (1) The siderite with a particle size of 8 mm to 40 mm is conveyed from the silo to the bottom silo 2 of the belt-type pellet roaster through the bottom material belt conveyor.

[0084] (2) The siderite lumps are continuously and evenly spread on the belt pellet roasting machine trolley from the bottom bunker 2. The siderite lumps move with the trolley at a certain speed and pass through the drying section, preheating section 5, roasting section 6, soaking section 7 and cooling section in sequence.

[0085] The high-temperature flue gas generated by the combustion of coke oven gas in the belt pellet roaster is ejected from the furnace through the siderite material layer for pre-oxidation, roasting and equalization.

[0086] The waste gas from the soaking section 7 and the roasting section 6 is circulated to the preheating section 5 and the exhaust drying section 4 through the heat recovery fan 15 for use.

[0087] II The hot air from the cooling section 9 is sent to the blast drying section 3 through the blast drying induced draft fan 17 for drying.

[0088] The hot air from the cooling section 8 enters the equalizing, roasting and preheating section 5 through the direct recuperation principle as the combustion-supporting gas for the coal gas of the belt-type pellet roaster.

[0089] The siderite is dried, dehydrated, pre-oxidized, oxidized and roasted, and then soaked, during which FeCO3 is oxidized and decomposed, and S is oxidized and removed. After cooling, it is discharged from the belt pellet roaster and enters the finished product warehouse or yard. The entire process is equipped with a desulfurization and denitrification system to meet environmental protection requirements.

[0090] (3) The feeding rate of siderite lump ore is 500-550t / h, the thickness of the siderite lump ore layer is about 400mm, and the trolley speed is 3.0-3.5m / min. The siderite stays on the belt pellet roaster for about 36-42min.

[0091] (4) The furnace temperature of the roasting section 6 is 1200-1250°C, and the furnace hood temperature of the soaking section 7 is 1080-1100°C.

[0092] (6) During the roasting process on the belt pellet roaster, siderite decomposes due to heat, resulting in cracks or explosions. During the transportation process, it will further break up. Therefore, before use, it is necessary to screen the raw materials according to the requirements of the blast furnace or converter to ensure the quality of the raw materials entering the furnace.

[0093] The present invention is described above by way of example in conjunction with the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-mentioned methods. As long as various non-substantial improvements are made using the method concept and technical solution of the present invention; or the above concept and technical solution of the present invention are directly applied to other occasions without improvement, they are all within the protection scope of the present invention.

Claims

1. A method for processing siderite, characterized in that: Includes steps: S1, conveying the siderite lump ore to the belt pellet roaster; S2, dehydrating the siderite lump; S3, pre-oxidation treatment of the siderite lump ore; S4, oxidizing and roasting the siderite lump; S5, performing a heat treatment on the siderite lump; S6. Cooling the siderite lump.

2. The siderite processing method according to claim 1, characterized in that: The step S2 comprises: S201, preliminarily drying the siderite lump ore; S202, secondary drying of the siderite lump ore.

3. The siderite processing method according to claim 2, characterized in that: The belt pellet roasting machine comprises a blast drying section, an exhaust drying section, a preheating section, a roasting section, a soaking section and a cooling section which are arranged in sequence; in the blast drying section, the siderite lumps are preliminarily dried; in the exhaust drying section, the siderite lumps are secondary dried.

4. The siderite processing method according to claim 3, characterized in that: The hot air generated in the cooling section is sent to the blast drying section through the blast drying induced draft fan.

5. The siderite processing method according to claim 3, characterized in that: The waste gas generated in the soaking section and / or the roasting section is sent to the exhaust drying section through a heat recovery fan.

6. The siderite processing method according to any one of claims 3 to 5, characterized in that: The waste gas generated in the soaking section and / or the roasting section is sent to the preheating section through a heat recovery fan.

7. The siderite processing method according to any one of claims 3 to 5, characterized in that: The step S6 comprises: S601, cooling the siderite lump ore for the first time; S602, cooling the siderite lump ore for a second time.

8. The siderite processing method according to claim 7, characterized in that: The cooling section includes a cooling section I and a cooling section II. In the cooling section I, the siderite lump is cooled for the first time; and in the cooling section II, the siderite lump is cooled for the second time.

9. The siderite processing method according to any one of claims 1 to 8, characterized in that: The particle size of the siderite lump ore is between 8 mm and 40 mm.

10. Siderite processing equipment, characterized in that: Used in the siderite processing method described in any one of claims 1 to 8.

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