A sintering method for high-proportion high-phosphorus non-mainstream iron ore powder and sintered ore

Abstract

The present invention relates to a sintering method and sintered ore of a high-proportion high-phosphorus non-mainstream iron ore powder, belonging to the technical field of iron ore smelting. The sintering method is: in the sintering batching link, 3%-5% of manganese iron ore and 0-1.5% of coke powder are additionally added to the sintering mixture by weight, the manganese iron ore contains MnO, and the purpose of sintering dephosphorization is achieved through chemical reaction under the thermodynamic conditions provided by the sintering combustion layer. The sintered ore is obtained by sintering the sintering method of a high-proportion high-phosphorus non-mainstream iron ore powder. In the dephosphorization process of the present invention, no harmful gases such as Cl2 are involved, and the environment is harmless; the reactants directly participate in the dephosphorization process, which is immediate and efficient; the sintering grade is ensured without affecting the slag amount; the dephosphorization cost is low, which complies with the principle of reducing costs before iron.

Description

Technical Field

[0001] The invention relates to a sintering method of high-proportion high-phosphorus non-mainstream iron ore powder and sintered ore, belonging to the technical field of iron ore smelting. Background Art

[0002] After decades of development, my country's blast furnace smelting has now formed a stable charge structure of "high-basicity sintered ore + acidic pelletized ore + natural lump ore". In order to reduce production costs, some domestic steel companies have shifted the choice of sintered ore to non-mainstream mineral powders such as JMBF, Atlas, and PMI. However, this type of non-mainstream mineral powder is generally accompanied by a large amount of apatite (Ca5(PO4)3F), and the current pre-iron process can hardly achieve effective dephosphorization. After sintering with a higher proportion of non-mainstream mineral powder, a large amount of phosphorus is sent to the converter workshop together with the molten iron, resulting in an increase in the production cost of the converter. The converter dephosphorization process takes a long time, and the production efficiency is low, which affects the production of low-phosphorus steel grades. Therefore, high phosphorus has become one of the restrictive links for the high proportion of non-mainstream ores.

[0003] After searching, the inventor team found that the patent application with publication number CN 107904397 B involves a dephosphorization method based on a sintering gasification dephosphorization recovery device. This method converts the P in the iron ore raw material into a phosphorus-containing product PCl3 gas; then the exhaust gas is cooled by a condenser, so that the phosphorus-containing product PCl3 gas with a low boiling point is cooled and turned into liquid and enters the dephosphorization product collection container for enrichment and recovery. The patent application with publication number CN 101514394 A involves a sintering dephosphorization agent, which is composed of three raw materials: calcium chloride, silicon dioxide and carbon powder. Through chemical reactions, the phosphorus content in the sintered ore meets the subsequent use requirements.

[0004] However, the above two patent applications have the following problems: (1) As an additive / dephosphorizing agent for dephosphorization reaction, a large amount of calcium-based minerals and silicates need to be added, which reduces the grade of sintered ore and increases the amount of slag in the subsequent blast furnace smelting process, which is not conducive to smooth production; (2) During the sintering process, the introduction of Cl - / Cl2 and other intermediate products as dephosphorization reducing agents pollute the environment, are harmful to the human body, and react with H + When combined, corrosion of equipment / pipelines shortens production life; (3) Dephosphorization agents are expensive, which runs counter to the original intention of reducing pre-iron production costs. Summary of the invention

[0005] In order to solve the above problems, the present invention discloses a sintering method and sintered ore of high-proportion high-phosphorus non-mainstream iron ore powder, and the specific technical scheme thereof is as follows:

[0006] A sintering method for high-proportion high-phosphorus non-mainstream iron ore powder comprises the following steps:

[0007] The mass of the high-phosphorus non-mainstream iron ore powder accounts for ≤40% of the total mass of the sintering ingredients. The high-phosphorus non-mainstream iron ore powder is associated with apatite Ca5(PO4)3F. During the sintering batching process, 3%-5% of manganese iron ore and 0-1.5% of coke powder are additionally added to the sintered high-phosphorus non-mainstream iron ore powder. The manganese iron ore contains MnO. Under the thermodynamic conditions provided by the sintering combustion layer, the purpose of sintering dephosphorization is achieved through the following chemical reaction (1):

[0008] 2Ca5(PO4)3F+15C+11SiO2+4MnO=15CO(g)+3P2(g)+CaF2+9CaSiO3+2Mn2SiO4 (1).

[0009] Further, when the high-phosphorus non-mainstream iron ore powder accounts for 0-20% of the total mass of the sintering ingredients, the mass percentage of manganese iron ore added is 3%;

[0010] When the high-phosphorus non-mainstream iron ore powder accounts for 20%-40% of the total mass of the sintering ingredients, the mass percentage of the added manganese iron ore is 5%.

[0011] Furthermore, when the proportion of the high-phosphorus non-mainstream iron ore powder to the total mass of the sintering ingredients is 0-10%, no additional coke powder is required;

[0012] When the high-phosphorus non-mainstream iron ore powder accounts for 10%-20% of the total mass of the sintering ingredients, the mass percentage of the coke powder is increased by 0.5%-1.0%;

[0013] When the high-phosphorus non-mainstream iron ore powder accounts for 20%-30% of the total mass of the sintering ingredients, the mass percentage of the coke powder is increased by 1.0%-1.5%;

[0014] When the high-phosphorus non-mainstream iron ore powder accounts for 30%-40% of the total mass of the sintering ingredients, the mass percentage of the coke powder is increased by 1.5%.

[0015] Furthermore, the composition and mass percentage of the high-phosphorus non-mainstream iron ore powder are: TFe 55%-62%, SiO2 5.5%-7.0%, Al2O3 0%-1.0%, MgO 0%-1%, CaO 0%-1%, P>1.0%, and burn loss 0-10%.

[0016] Furthermore, the composition and mass percentage of the manganese iron ore are: manganese oxide 20-30%, TFe 40-60%, SiO2 5%-15%, P < 0.1%, and burn loss 0-10%.

[0017] Furthermore, in the reducing atmosphere formed by the combustion of fuel in the sintering material layer, MnO in the ferromanganese ore reacts with apatite Ca5(PO4)3F associated with high-phosphorus iron ore under the thermodynamic conditions provided by the combustion layer at an air temperature greater than 1200°C, thereby realizing the gasification of the P element. The gasified P element is extracted to the sintering flue through negative pressure, and then chemically reacts with dust particles in the sintering flue gas to be converted into phosphate; it is chemically oxidized into phosphorus oxides in the oxidizing atmosphere of the sintering flue gas, and finally the phosphate and phosphorus oxides are enriched and recovered through the sintering dust removal system.

[0018] Furthermore, the specific chemical reaction formulas of the gasified P element in the dust particles to convert into phosphate are as follows (2), (3) and (4), and the specific chemical reaction formula of the P element in the dust particles to convert into phosphorus oxide in the oxidizing atmosphere of the sintering flue gas is as follows (5):

[0019] 6CaO+P2(g)+5O2(g)=2Ca3(PO4)2(2)

[0020] 6MgO+P2(g)+5O2(g)=2Mg3(PO4)2(3)

[0021] 2A12O3+P2(g)+5O2(g)=4AlPO4(4)

[0022] 2P2(g)+5O2(g)=2P2O5(g) (5).

[0023] Furthermore, the sintering process is to first mix all the used ore powders in proportion in the material yard through a stacker and reclaimer, and then send them to the sintering batching bin and mix them with other sintering auxiliary materials in proportion on the belt. The sintering auxiliary materials include limestone, quicklime, dolomite, coke powder and return ore;

[0024] The additional manganese iron ore is stored in a separate sintering batching bin for storing manganese iron ore, and is fed into the belt according to the required proportion and mixed with the mixed material on the belt. The coke powder is also stored in a separate sintering batching bin for storing coke powder, and is fed into the belt according to the required proportion and mixed with the mixed material on the belt. After all the materials are mixed, a mixture is formed and sent to the sintering machine through the unloading scale and the belt. After the materials are pressed and leveled, the coke oven gas is ignited with an ignition temperature of 1050℃±50℃. The mixed materials are all on the trolley. At this time, a vacuum is applied from the bottom of the trolley to form a negative pressure environment of 7kPa±2kPa. After ignition, the trolley continues to move forward. At this time, the negative pressure at the bottom is 13kPa±2kPa, until the tail of the trolley, completing the entire sintering process. All the powder ores undergo physical and chemical reactions in an environment with a high temperature of more than 1300℃ to form blocks, which are then crushed and screened and sent to the next blast furnace process for production.

[0025] Furthermore, the C in the sintering comes from coke powder, and the mass content of C in the coke powder is 85%±2%; the sintering ingredients are iron ore powder of different origins and compositions and return ore in the sintering auxiliary materials; the flux is quicklime, dolomite and limestone in the sintering auxiliary materials; the fuel is coke powder in the sintering auxiliary materials; the material surface height of the trolley during the sintering process is 800mm±50mm, and the width is 5m±1.5m, and the material surface height is the stacking height of the mixed ore. Inside such a volume, there is a combustion reaction of coke powder, the coke powder is concentrated, and the coke powder is segregated, so a CO / C reducing atmosphere will be formed locally.

[0026] Furthermore, the negative pressure extraction of gasified P element is specifically as follows: accompanying the entire sintering process, during normal sintering, the negative pressure is 13kPa±1kPa, and the reduced P is in a gasified state. After being extracted into the sintering flue, it reacts with other particulate matter in the flue through gas-solid reaction to generate phosphorus oxides and is enriched.

[0027] Furthermore, during the normal sintering process, the oxygen content in the flue is 16%-20%, and it also includes CO, CO2, N2, sulfide and other air components. The temperature in the flue is 100-200°C.

[0028] The present invention application also claims to protect the sintered ore obtained by the sintering method of the above-mentioned high-proportion high-phosphorus non-mainstream iron ore powder.

[0029] Furthermore, the mass contents of the sintered ore components are: TFe 55%-57%, SiO2 5.0%-5.6%, Al2O3 1.8%-2.5%, MgO 1.8%-2.2%, CaO 9.8%-10.5%, p 0.10%-0.20%, the average particle size of the sintered ore after granulation is 20-22 mm, of which the mass content of the 10-5 mm particle size is 20±5%, and the mass content of the <5 mm particle size is <10%, the low-temperature reduction pulverization value RDI+3.15mm of the sintered ore is 68%-72%, and the reduction degree is 78%-82%.

[0030] The RDI index is an index of the reduction and pulverization performance of sintered ore at 500℃, reflecting the degree of pulverization of sintered ore when reduced in the low temperature area of ​​blast furnace (450~550℃), and has an important influence on the permeability of blast furnace charge column. The RDI+3.15mm test is the proportion of sifted with 6.3mm mesh that is greater than 6.3mm. Within a reasonable range, the larger the value, the better the performance.

[0031] The working principle of the present invention is:

[0032] During the sintering process, the sintering material layer is mainly composed of an oxidizing atmosphere with some reducing atmospheres. Due to the oxygen potential, apatite is almost difficult to be reduced during the sintering process, resulting in all phosphorus remaining in the sintered ore and entering the blast furnace. However, by adding high manganese ore, certain chemical reactions are promoted under sintering conditions, so that phosphorus reduction can be achieved to a certain extent during the sintering process, achieving gasification dephosphorization, thereby breaking the shackles that limit the use ratio of high-phosphorus non-mainstream iron ore powder, and also increasing the use ratio of low-priced high manganese ore.

[0033] The beneficial effects of the present invention are:

[0034] Compared with the prior art, the present invention does not involve harmful gases such as Cl2 in the dephosphorization process, which is environmentally friendly and harmless; the reactants directly participate in the dephosphorization process, which is immediate and efficient; the sintering grade is ensured without affecting the slag volume; the dephosphorization cost is low, which complies with the principle of reducing costs before iron production. Through the technical solution of the present invention, it is possible to significantly dephosphorize, improve the sintering ratio of high-phosphorus non-mainstream iron ore powder, and reduce the production cost before iron production. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a schematic diagram of the process of the present invention. DETAILED DESCRIPTION

[0036] The present invention is further explained below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the following specific embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention.

[0037] The sintering method of the high-proportion high-phosphorus non-mainstream iron ore powder comprises the following steps:

[0038] The mass of high-phosphorus non-mainstream iron ore powder accounts for ≤40% of the total mass of sintering ingredients. The mainstream sintering ore powder is generally the ore powder of the three major mines of VALE / BHP / RATIO, and the P content generally does not exceed 0.1%; other ore powders are generally called non-mainstream iron ore powder. Non-mainstream ore powder is generally accompanied by a large amount of apatite (Ca5(PO4)3F), that is, the high-phosphorus non-mainstream iron ore powder in the present application.

[0039] According to the proportion of high-phosphorus non-mainstream ore in the sintering batch, 3%-5% of manganese iron ore and 0-1.5% of coke powder are additionally added to the sintering batch. Under the thermodynamic conditions provided by the sintering combustion layer, the purpose of sintering dephosphorization is achieved through reaction (1).

[0040] 2Ca5(PO4)3F+15C+11SiO2+4MnO=15CO(g)+3P2(g)+CaF2+9CaSiO3+2Mn2SiO4 (1)

[0041] Manganese iron ore is an iron ore containing 20%-30% MnO. In the reducing atmosphere formed by the combustion of fuel in the sintering batching layer, MnO in the manganese iron ore reacts with apatite associated with high-phosphorus iron ore under the thermodynamic conditions provided by the combustion layer (T>1200℃), realizing the gasification of P element. The gasified P element is extracted to the sintering flue under negative pressure, and then reacts with dust particles in the sintering flue gas to convert into phosphate (2), (3), (4); and is oxidized to phosphorus oxide through reaction (5) in the oxidizing atmosphere of the sintering flue gas.

[0042] 6CaO+P2(g)+5O2(g)=2Ca3(PO4)2(2)

[0043] 6MgO+P2(g)+5O2(g)=2Mg3(PO4)2(3)

[0044] 2A12O3+P2(g)+5O2(g)=4AlPO4(4)

[0045] 2P2(g)+5O2(g)=2P2O5(g) (5)

[0046] Finally, the phosphate and phosphorus oxides are enriched and recovered through the sintering dust removal system. The additive manganese iron ore involved in the technical solution of the present invention is a common iron ore in the iron smelting field. The Fe and Mn elements contained in it are beneficial elements for pre-iron production and will not have a negative impact on the grade; no harmful gas is generated in the dephosphorization process, and the generated gaseous phosphorus element is enriched and recovered through a series of reactions in the sintering flue, and the sintering flue gas can be discharged harmlessly after normal processes.

[0047] The general sintering process is: first, all the mineral powders used are mixed evenly in a certain proportion in the material yard through a stacker and reclaimer, and then sent to the sintering batching bin, and mixed with other sintering auxiliary materials (such as limestone, quicklime, dolomite, fuel coke powder, and return ore) in proportion on the belt and sent to sintering. The additional addition of manganese iron ore here means storing manganese iron ore in a sintering batching bin alone, and mixing it in the required proportion (it can be regarded as another sintering ingredient). The additional addition of coke powder is similar, but the coke powder itself has a bin, that is, the original normal addition is 4%, and the present invention applies for 5.5%. After all the materials are mixed, they are sent to the sintering machine through a feeding scale and a belt. After the material is pressed and leveled, the coke oven gas is ignited (ignition temperature 1050℃±50℃). At this time, a suction negative pressure of about 7kPa should be given from the bottom of the trolley (the mixed ore is on the trolley). After ignition, the trolley continues to move forward at a speed of 2.0m / min. At this time, the negative pressure at the bottom is about 13kPa. The entire sintering process is completed at the tail end of the trolley. All the powdered ore undergoes physical and chemical reactions at a high temperature of 1300°C to form blocks. After crushing and screening, it is sent to the next blast furnace process for production.

[0048] The C in sintering comes from coke powder, and the C content in coke powder is generally about 85%. Sintering ingredients: iron ore powder of different origins and compositions, flux: quicklime, dolomite, limestone; fuel: coke powder. The height (thickness) of the sintering trolley is generally 800mm, and the width is generally 5 meters. In such a volume, there is a combustion reaction of coke powder, and a reducing atmosphere (CO / C) will be formed locally. The reason for the reduction atmosphere (CO / C) is the segregation of coke powder, etc. The coke powder is relatively concentrated on the sintering trolley.

[0049] The negative pressure extraction of gasified P element is as follows: during the whole sintering process, during normal sintering, the negative pressure is 13kPa±1kPa, and the reduced P is in a gasified state. After being extracted into the sintering flue, it reacts with other particulate matter in the flue through gas-solid reaction to generate phosphorus oxides and is enriched.

[0050] During normal sintering, the oxygen content in the flue is 16%-20%, and the rest are CO, CO2, N2, sulfides, etc. The temperature in the flue is generally 100-200℃. The concentration of P depends on the P content in the mineral powder and the amount of additional coke powder added, that is, the amount that is reduced; in addition, the single substance of P is easily oxidized in the oxidizing atmosphere of the flue, and single substance P almost does not exist.

[0051] The proportions of the manganese iron ore, the additional fuel coke powder and the high-phosphorus ore powder involved can be adjusted in combination with the production conditions. Any proportioning scheme can achieve the dephosphorization reaction described in formula (1). The only difference is limited to the dephosphorization effect. Generally speaking, the addition of sintering auxiliary materials according to the technical scheme of the present invention is conducive to the forward reaction by increasing the concentration of reactants, and a significant dephosphorization effect can be achieved. However, considering the problems such as the material reaction efficiency in the actual reaction process and other additional loss problems in the sintering process, it is necessary to increase the appropriate proportion for addition when using it. Therefore, the technical scheme of the present invention fully considers the sintering conditions and production practices, and makes corresponding provisions for the proportion of raw materials and auxiliary materials.

[0052] See also Figure 1 The core of the present invention application is to disclose the following raw material ratios:

[0053] When the high-phosphorus non-mainstream iron ore powder accounts for 0-20% of the total mass of the sintering ingredients, the mass percentage of manganese iron ore added is 3%;

[0054] When the high-phosphorus non-mainstream iron ore powder accounts for 20%-40% of the total mass of the sintering ingredients, the mass percentage of the added manganese iron ore is 5%.

[0055] When the proportion of the high-phosphorus non-mainstream iron ore powder to the total mass of the sintering ingredients is 0-10%, no additional coke powder is required;

[0056] When the high-phosphorus non-mainstream iron ore powder accounts for 10%-20% of the total mass of the sintering ingredients, the mass percentage of the coke powder is increased by 0.5%-1.0%;

[0057] When the high-phosphorus non-mainstream iron ore powder accounts for 20%-30% of the total mass of the sintering ingredients, the mass percentage of the coke powder is increased by 1.0%-1.5%;

[0058] When the high-phosphorus non-mainstream iron ore powder accounts for 30%-40% of the total mass of the sintering ingredients, the mass percentage of the coke powder is increased by 1.5%.

[0059] Six embodiments of the present invention in actual sintering production are given below. The sintering methods used in the embodiments are as follows:

[0060] Step 1: Coarsely mix various mineral powders, then send them into a primary mixer, add fuel, flux, and 80%-90% of the total water volume to mix them once; the total water volume of the mixture is controlled at 7.0%±0.5 of the total material;

[0061] Various mineral powders are mixed evenly to form sintering ingredients. The mineral powders and their mass percentages of the sintering ingredients are as follows:

[0062] KF (ka powder) 5%~30%, BF (BRBF powder) 0%~15%, CTF (super special powder) 0%~30%, MKF (Mike powder) 15%~40%, high phosphate ore (i.e. high phosphorus non-mainstream iron ore powder) 0%~40%, JF (Brazilian fine powder) 0%~10%, manganese iron ore 0%~35%.

[0063] Step 2, continue to feed the mixture in step 1 into the secondary mixer, add atomized water with a mass of 10%-20% of the total water volume, and mix and granulate;

[0064] Step 3: Add the material in step 2 into the sintering cup (cup inner diameter 300mm, height 800mm, loading amount 100kg) through the hopper, keep the material layer height 800mm, and flatten the material surface;

[0065] Step 4, start the gas igniter, move the gas to the top of the material surface when the gas temperature reaches about 1050°C, start the ignition negative pressure, set the negative pressure at -7kPa, ignite and sinter, set the ignition time to 2min, after the ignition is completed, start the exhaust negative pressure fan, and set the negative pressure at -14kPa;

[0066] Step 5: When the exhaust gas temperature reaches the highest point and drops rapidly to over 150°C through online detection equipment, the sintering is considered complete. At this time, the cooling fan is started, the negative pressure is set to -5kPa, and the exhaust gas temperature is cooled to 50°C.

[0067] Step 6: crush, screen and sample the sintered ore sample in the sintering cup to test and analyze relevant indicators.

[0068] Among the six embodiments provided in the present invention, only the various mineral powder components in step 1 are different. The mineral powder is a mixture, and the components include KF (card powder), BF (BRBF powder), CTF (super special powder), MKF (Mike powder), high phosphate ore, JF (Brazilian fine powder), manganese iron ore, return ore, quicklime, dolomite, limestone, and coke powder. All of these components can be obtained from the raw material plant of the steel enterprise. Each component is also a mixture, including components: TFe, SiO2, CaO, MgO, Al2O3, P, Mn and other impurity components that cannot be counted.

[0069] The high-phosphorus ore in Tables 1 to 5 is high-phosphorus non-mainstream iron ore powder.

[0070] Table 1 Composition and mass percentage of mineral powder components used in Examples 1 to 6

[0071]

[0072] The first column in Table 1 is the component name of the mineral powder, and the first line is the component name of each component. When calculating the sum of the components in the first column of the mineral powder, the moisture in Table 1 is not included, and some elements are not displayed due to analysis reasons, and TFe has a conversion process, which directly converts the oxide into a single substance, so the value of a row is generally less than 100. Among them, TFe represents the total iron content, the burn loss represents the weight percentage reduced by volatilizing or oxidizing and decomposing organic matter, sulfide, etc. in the ore at high temperature, and the moisture represents the physical water of the material.

[0073] Table 2 shows various mineral powders used in step 1 in Examples 1 to 6 and their mass percentages. Various mineral powders are mixed evenly according to their mass ratios to obtain sintering ingredients.

[0074] Table 2 Mineral powders and their mass percentages of sintering ingredients in Examples 1 to 6

[0075]

[0076] Table 3 shows the various mineral powders used in step 1 in Examples 7 to 12 and their mass percentages.

[0077] Table 3 Mineral powders and their mass percentages of sintering ingredients in Examples 7 to 12

[0078]

[0079] Table 4 shows the mixture formed by the sintering ingredients and sintering auxiliary materials (sintering auxiliary materials include return ore, fuel and flux, flux: quicklime, dolomite, limestone; fuel: coke powder) used in step 1 of Examples 1 to 6, and the additional coke powder (additional addition in some examples). A certain amount of additional coke powder was added in Example 3 and Example 6.

[0080] Table 4 Mass ratio and percentage of the mixed materials of Examples 1 to 6

[0081]

[0082] In Table 4, the sum of the mass percentages of sintering ingredients and return ore, quicklime, dolomite, limestone and coke powder is 100%, and the mass percentage of additional coke powder refers to the mass ratio of additional coke powder to mixed ore, return ore, quicklime, dolomite, limestone, coke powder and additional coke powder.

[0083] The mixed material uniformly mixed according to Table 4 enters the trolley for sintering through the mixing belt.

[0084] Table 5 shows the mixture formed by the sintering ingredients and sintering auxiliary materials (sintering auxiliary materials include return ore, fuel and flux, flux: quicklime, dolomite, limestone; fuel: coke powder) used in step 1 in Examples 7 to 12, and the additional coke powder (additional addition in some examples). A certain amount of additional coke powder was added in Examples 9 and 12.

[0085] Table 5 Mass ratio and percentage of the mixed materials of Examples 7 to 12

[0086]

[0087] The present invention provides 12 embodiments. The composition and performance indicators of the sintered ore obtained in embodiments 1 to 6 are shown in Table 6 below, and the composition and performance indicators of the sintered ore obtained in embodiments 7 to 12 are shown in Table 7 below.

[0088] Table 6 Composition and performance index of sintered ore finished products of Examples 1 to 6

[0089]

[0090] Table 7 Composition and performance index of sintered ore finished products of Examples 7 to 12

[0091]

[0092] The average particle size of the sintered ore after granulation is 20-22mm, of which the mass content of 10-5mm particle size is 20±5%, and the mass content of <5mm particle size is <10%. The low-temperature reduction pulverization value of the sintered ore RDI+3.15mm is 68%-72%, and the reduction degree is 78%-82%.

[0093] The chemical composition of the sintered ore in this example and the composition of the ore powder used in the experiment were determined by wavelength dispersive X-ray fluorescence spectrometry (cobalt internal standard method) in accordance with GB / T 6730.87-2023 “Determination of total iron and other multi-element contents in iron ore”.

[0094] The particle size test of sintered ore in Tables 6 and 7 was carried out in accordance with YB / T 4605-2017 "Technical Specifications for Online Automatic Sampling, Sample Preparation, Particle Size Analysis and Drum Strength Determination of Sintered Ore".

[0095] The low-temperature reduction pulverization index of the sintered ores in Tables 6 and 7 was determined with reference to GB 13242-2017 “Low-temperature pulverization test of iron ore using a cold drum after static reduction”.

[0096] The reduction degree of the sintered ores in Tables 6 and 7 was determined with reference to GB / T 24189-2009 “Determination of the reducibility of iron ores for blast furnaces expressed by the final reduction degree index”.

[0097] The raw material ratios and dephosphorization effects of Examples 1 to 12 are given below, see Table 8 for details.

[0098] Table 8 Technical solutions and dephosphorization effects of the examples

[0099]

[0100] In the sintering production process, the SiO2 in the sintering mixture layer is generally maintained at around 4.6% to 5.0%, so there is no need to add additional silica minerals; at the same time, steel companies generally add about 3.5% to 4.0% coke powder to the sintering mixture, so no additional coke powder is added in Examples 1, 2, 4, 5, 7, 8, 10, and 11; Examples 1, 4, 7, and 10 are normal sintering, reflecting the effect of adding different proportions of high-phosphate rock powder on the composition of the sintered ore, as comparative examples.

[0101] By comparing the data of the above embodiments, embodiments 1, 2, and 3 are a group, embodiments 4, 5, and 6 are a group, embodiments 7, 8, and 9 are a group, and embodiments 10, 11, and 12 are a group, and the dephosphorization effects are compared within each group. It can be seen that the dephosphorization effect of the technical solution of the present invention is obvious, and it can effectively break the phosphorus load limitation brought about by the application of high-phosphorus non-mainstream iron ore powder after sintering. The technical solution of the present invention can reduce the phosphorus load in the sintered ore layer by more than 20%; if the economic perspective of the enterprise is considered, the technical solution of the present invention is used selectively, and the phosphorus load in the sintered ore layer can be reduced by less than 10%. The technical solution of the present invention can be actually applied to sintering production, saving a lot of manpower, material resources and time consumption, and achieving the expected effect of the present invention.

[0102] With the above-mentioned ideal embodiments of the present invention as inspiration, through the above-mentioned description content, relevant personnel can make various changes and modifications without departing from the scope of the technical idea of ​​the present invention.

Claims

1. A sintering method for high-proportion high-phosphorus non-mainstream iron ore powder, characterized in that: The following steps are involved: The mass of the high-phosphorus non-mainstream iron ore powder accounts for ≤40% of the total mass of the sintering ingredients. The high-phosphorus non-mainstream iron ore powder is associated with apatite Ca5(PO4)3F. During the sintering batching process, 3%-5% of manganese iron ore and 0-1.5% of coke powder are additionally added to the sintered high-phosphorus non-mainstream iron ore powder. The manganese iron ore contains MnO. Under the thermodynamic conditions provided by the sintering combustion layer, the purpose of sintering dephosphorization is achieved through the following chemical reaction (1): 2Ca5(PO4)3F+15C+11SiO2+4MnO=15CO(g)+3P2(g)+CaF2+9CaSiO3+2Mn2SiO4 (1); When the proportion of the high-phosphorus non-mainstream iron ore powder to the total mass of the sintering ingredients is greater than 0 and less than or equal to 20%, the mass percentage of the added manganese iron ore is 3%; When the proportion of the high-phosphorus non-mainstream iron ore powder to the total mass of the sintering ingredients is greater than 20% and less than or equal to 40%, the mass percentage of the added manganese iron ore is 5%; When the proportion of the high-phosphorus non-mainstream iron ore powder to the total mass of the sintering ingredients is greater than 0 and less than or equal to 10%, no additional coke powder is required; When the proportion of the high-phosphorus non-mainstream iron ore powder to the total mass of the sintering ingredients is greater than 10% and less than or equal to 20%, the mass percentage of the coke powder is increased by 0.5%-1.0%; When the proportion of the high-phosphorus non-mainstream iron ore powder to the total mass of the sintering ingredients is greater than 20% and less than or equal to 30%, the mass percentage of the coke powder is increased by 1.0%-1.5%; When the proportion of the high-phosphorus non-mainstream iron ore powder to the total mass of the sintering ingredients is greater than 30% and less than or equal to 40%, the mass percentage of the coke powder is increased by 1.5%; The composition and mass percentage of the high-phosphorus non-mainstream iron ore powder are: TFe 55%-62%, SiO2 5.5%-7.0%, Al2O3 0%-1.0%, MgO 0%-1%, CaO 0%-1%, P>1.0%, and burn loss 0-10%; The composition and mass percentage of the manganese iron ore are: manganese oxide 20-30%, TFe 40-60%, SiO2 5%-15%, P < 0.1%, and burn loss 0-10%; In the reducing atmosphere formed by fuel combustion in the sintering material layer, the MnO in the ferromanganese ore reacts with the apatite Ca5(PO4)3F associated with the high-phosphorus iron ore in the combustion layer under the thermodynamic conditions provided by the temperature being greater than 1200° C., thereby realizing the gasification of the P element. The gasified P element is extracted to the sintering flue through negative pressure, and then chemically reacts with the dust particles in the sintering flue gas to be converted into phosphate; it is chemically oxidized into phosphorus oxides in the oxidizing atmosphere of the sintering flue gas, and finally the phosphate and phosphorus oxides are enriched and recovered through the sintering dust removal system; The specific chemical reaction formulas for the gasified P element to be converted into phosphate by chemical reaction in the dust particles are as follows (2), (3) and (4), and the specific chemical reaction formula for being oxidized into phosphorus oxide in the oxidizing atmosphere of sintering flue gas is as follows (5): 6CaO+P2(g)+5O2(g)=2Ca3(PO4)2(2) 6MgO+P2(g)+5O2(g)=2Mg3(PO4)2(3) 2A12O3+P2(g)+5O2(g)=4AlPO4(4) 2P2(g)+5O2(g)=2P2O5(g) (5).

2. The sintering method of high-proportion high-phosphorus non-mainstream iron ore powder according to claim 1, characterized in that: The sintering process is to first mix all the used ore powders in proportion in the material yard through the stacker and reclaimer, and then send them to the sintering batching bin and mix them with other sintering auxiliary materials in proportion on the belt. The sintering auxiliary materials include limestone, quicklime, dolomite, coke powder and return ore. The additional manganese iron ore is stored in a separate sintering batching bin for storing manganese iron ore, and is fed into the belt according to the required proportion and mixed with the mixed materials on the belt. The coke powder is also stored in a separate sintering batching bin for storing coke powder, and is fed into the belt according to the required proportion and mixed with the mixed materials on the belt. After all the materials are mixed, a mixture is formed, which is sent to the sintering machine through a feeding scale and a belt. After the materials are pressed and leveled, the coke oven gas is ignited. The ignition temperature is 1050℃±50℃. The mixture is all on the trolley. At this time, a vacuum is applied from the bottom of the trolley to form a negative pressure environment of 7kPa±2kPa. After ignition, the trolley continues to move forward. At this time, the negative pressure at the bottom is 13kPa±2kPa, until the tail of the trolley, completing the entire sintering process. All the powder ores undergo physical and chemical reactions in an environment with a high temperature of more than 1300℃ to form blocks, which are then crushed and screened and sent to the next blast furnace process for production.

3. The sintering method of high-proportion high-phosphorus non-mainstream iron ore powder according to claim 1, characterized in that: The C in the sintering comes from coke powder, and the mass content of C in the coke powder is 85%±2%; the sintering ingredients are iron ore powder of different origins and compositions and return ore in the sintering auxiliary materials; the flux is quicklime, dolomite and limestone in the sintering auxiliary materials; the fuel is coke powder in the sintering auxiliary materials; during the sintering process, the material surface height of the trolley is 800mm±50mm, and the width is 5m±1.5m, and the material surface height is the stacking height of the mixed ore. Inside such a volume, there is a combustion reaction of coke powder, the coke powder is concentrated, and the coke powder is segregated, so a CO / C reducing atmosphere will be formed locally.

4. The sintering method of high-proportion high-phosphorus non-mainstream iron ore powder according to claim 1, characterized in that: The negative pressure extraction of gasified P element is specifically: accompanying the entire sintering process, during the normal sintering process, the negative pressure is 13kPa±1kPa, and the reduced P is in a gasified state. After being extracted into the sintering flue, it reacts with other particulate matter in the flue through gas-solid reaction to generate phosphorus oxides and is enriched.

5. The sintering method of high-proportion high-phosphorus non-mainstream iron ore powder according to claim 4, characterized in that: During the normal sintering process, the oxygen content in the flue is 16%-20%, and it also includes CO, CO2, N2, sulfide and other air components. The temperature in the flue is 100-200°C.

6. The sintered ore obtained by the sintering method of high-proportion high-phosphorus non-mainstream iron ore powder according to any one of claims 1 to 5 is characterized in that: The mass contents of the sintered ore components are: TFe 55%-57%, SiO2 5.0%-5.6%, Al2O3 1.8%-2.5%, MgO 1.8%-2.2%, CaO 9.8%-10.5%, p 0.10%-0.20%, the average particle size of the sintered ore after granulation is 20-22 mm, of which the mass content of the 10-5 mm particle size is 20±5%, and the mass content of the <5 mm particle size is <10%, the low-temperature reduction pulverization value RDI+3.15mm of the sintered ore is 68%-72%, and the reduction degree is 78%-82%.

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