A method of controlling the quality of sintered ore

Abstract

The present application relates to the field of metallurgy, in particular to a kind of control method for stabilizing sinter quality.Sinter is formed by sintering after sintering raw materials, and the sintering raw materials include iron-containing ore powder, fuel and flux.The content of ferrous oxide in sinter is controlled by controlling the particle size and moisture content of fuel and adjusting the amount of fuel added, and the alkalinity of sinter is controlled by controlling the quality of flux raw materials and adjusting the ratio of flux raw materials.The fuel is sintering anthracite, and the flux raw materials include combinations of quicklime, dolomite and limestone.The present application controls the content of ferrous oxide in sinter by controlling the particle size and moisture content of fuel and adjusting the amount of fuel added, and controls the alkalinity of sinter by controlling the quality of flux raw materials and adjusting the ratio of flux raw materials, thereby achieving stable control of the alkalinity and content of ferrous oxide in sinter, avoiding large-scale fluctuations in sinter quality, and improving the quality stability of sinter.

Description

Technical Field

[0001] This invention relates to the field of metallurgy, and more specifically to a method for controlling the quality of sintered ore. Background Technology

[0002] Sintered ore is the most important raw material for blast furnace smelting, accounting for 60%-80% of the blast furnace feed. As blast furnace smelting develops towards large-scale and large-scale operations, the operational difficulty of blast furnace smelting is gradually increasing, which also puts forward higher quality requirements for sintered ore.

[0003] Sintered ore is produced by mixing iron ore powder with flux and fuel, thoroughly mixing the mixture, and then feeding it to a sintering machine under specific moisture conditions. The various particulate components melt into semi-molten particles and then solidify, forming sintered ore with a certain strength and chemical composition, which is then used in blast furnace smelting. The main indicators for evaluating the quality of sintered ore include basicity and ferrous oxide content. Ferrous oxide content can be adjusted by the amount of fuel added, while basicity, the ratio of calcium oxide (CaO) to silicon oxide (SiO2) content, can be adjusted by the amount of flux added.

[0004] However, in the actual production of sinter, the composition of the iron ore powder, flux, and fuel used as raw materials is not fixed, and the composition of raw materials varies greatly between different batches. This fluctuation in raw material composition leads to fluctuations in the quality of the produced sinter, significantly affecting its quality stability. Using sinter with poor quality stability for blast furnace smelting results in poor-quality steel products, or even scrap steel, causing serious production losses. Current technologies focus on improving quality indicators in sinter production, while research on the quality stability of sinter is relatively lacking. Therefore, there is an urgent need for a method to improve the quality stability of sinter. Summary of the Invention

[0005] To address the technical problems of large fluctuations in the composition of sinter raw materials and poor quality stability of the produced sinter, resulting in production losses in existing technologies, this invention provides a method for controlling the quality of sinter. This method controls the ferrous oxide content of the sinter by controlling the particle size and moisture content of the fuel and adjusting the fuel addition amount; and controls the basicity of the sinter by controlling the quality of the flux raw materials and adjusting the flux raw material ratio. This achieves stable control of the basicity and ferrous oxide content of the sinter, avoiding large fluctuations in sinter quality and improving the quality stability of the sinter.

[0006] The technical solution of the present invention is as follows:

[0007] A method for controlling the quality of stable sintered ore, wherein the sintered ore is formed by sintering a mixture of sintering raw materials, including iron ore powder, fuel, and flux; the ferrous oxide content of the sintered ore is controlled by controlling the particle size and moisture content of the fuel and adjusting the amount of fuel added; the basicity of the sintered ore is controlled by controlling the quality of the flux raw materials and adjusting the flux raw material ratio; the fuel is sintered anthracite, and the flux raw materials include a combination of quicklime, dolomite, and limestone.

[0008] Furthermore, the target ferrous oxide content of the sinter is 9.0%-10.0%; the target basicity of the sinter is determined according to actual production needs.

[0009] Furthermore, by mass percentage, the content of fuel particles with a size ≤3mm in the fuel is controlled to be 80.0%±2%.

[0010] Furthermore, the fuel moisture content is controlled at 9.0% ± 1.0% by mass to suppress dust generation during fuel conveying and crushing.

[0011] Furthermore, specific measures to control the moisture content of fuel are as follows: first, sintered anthracite is piled into a coal pile with a height of not less than 10.5m; when using it, sintered anthracite is taken from the pile, leaving the bottom coal layer with a height of 0.6m, and only the coal layer with a height of more than 0.6m is taken.

[0012] Furthermore, the fuel blending ratio is adjusted using a three-tier adjustment method. Specifically, the ferrous oxide content and its trend in the previous 3-5 batches of sinter are analyzed. The deviation of the current actual ferrous oxide content from the target ferrous oxide content is calculated. If the actual ferrous oxide content is lower than the target ferrous oxide content, the fuel blending ratio is increased; conversely, if it is higher, the fuel blending ratio is decreased. If the deviation is ≤0.2%, the fuel blending ratio is increased or decreased by 0.03%; if 0.2% < deviation ≤0.5%, the fuel blending ratio is increased or decreased by 0.06%; and if the deviation is >0.5%, the fuel blending ratio is increased or decreased by 0.1%. This three-tier adjustment method allows for timely adjustments to the ferrous oxide content deviation. By increasing or decreasing the fuel blending ratio according to different deviations, the ferrous oxide content of the sinter can be quickly restored to the target value, improving production efficiency.

[0013] Furthermore, the quality of flux raw materials is controlled by adjusting the particle size, moisture content, and effective component content. By mass percentage, the content of particles ≤3mm in the flux is controlled to be ≥98%, and the moisture content <5%. Specifically, quicklime has a CaO content of 82%±2% and a SiO2 content ≤3.5%; dolomite has a CaO content ≥30%, a MgO content ≥19%, and a SiO2 content ≤2.5%; and limestone has a CaO content ≥51% and a SiO2 content ≤2.5%. Smaller particle sizes result in larger surface areas, and controlling particle size facilitates uniform mixing and composition during sintering. Moisture control prevents material blockage and sticking in the conveyor lines. Controlling the content of effective components in the flux contributes to its compositional stability, further improving the quality of the flux raw materials.

[0014] Furthermore, the CaO and SiO2 content of quicklime is controlled by combining high- and low-quality raw ores and controlling the kiln temperature; the CaO, MgO, and SiO2 content of dolomite and the CaO and SiO2 content of limestone are also controlled by combining high- and low-quality raw ores.

[0015] Furthermore, a flux ratio adjustment coefficient is established. When the effective components of the flux change, the flux raw material ratio is adjusted by combining the flux ratio adjustment coefficient with the actual required alkalinity. The ratio is expressed as a mass percentage.

[0016] A 1% increase in CaO content in quicklime leads to a 0.015% increase in the basicity of sintered ore.

[0017] A 1% increase in CaO content in limestone leads to a 0.010% increase in the basicity of sintered ore.

[0018] A 1% increase in SiO2 content in quicklime leads to a 0.020% decrease in the basicity of sintered ore.

[0019] A 1% increase in SiO2 content in limestone leads to a 0.012% decrease in the basicity of sintered ore.

[0020] A 1% increase in SiO2 content in dolomite leads to a 0.020% decrease in the basicity of sintered ore.

[0021] A 1% increase in the total SiO2 content in the flux resulted in a 0.030% decrease in the basicity of the sinter.

[0022] Increasing the proportion of quicklime by 0.05% increases the basicity of sinter by 0.01%.

[0023] Furthermore, the fuel also includes carbon-containing solid waste, which is stockpiled and added using the BLOCK stockpiling method. The carbon-containing solid waste includes gravity ash and coking ash, which are stockpiled and batched separately. The batching rate of gravity ash is 38±2 t / h, and the batching rate of coking ash is 8±1 t / h. The above batching rates ensure the continuous and stable flow of gravity ash and coking ash.

[0024] The beneficial effects of this invention are as follows:

[0025] 1. This invention controls the ferrous oxide content of sinter by controlling the fuel particle size and moisture content and adjusting the fuel addition amount, thereby reducing the fluctuation of ferrous oxide content in sinter and achieving stable control of ferrous oxide content in sinter. Applying sinter prepared using the method of this invention to blast furnace smelting is beneficial for stabilizing the gas flow in the upper part of the blast furnace, ensuring a consistent smelting reduction reaction rate, and increasing the output of molten iron.

[0026] 2. This invention controls the basicity of sinter by controlling the quality of flux raw materials and adjusting the flux raw material ratio. This avoids deviations in the adjustment of sinter basicity due to fluctuations in the composition of flux raw materials, further improving the quality stability of sinter and thus improving production efficiency. Detailed Implementation

[0027] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions in the embodiments of this invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0028] Example 1

[0029] A method for controlling the quality of stable sintered ore, wherein the sintered ore is produced by sintering a mixture of iron-bearing ore powder, fuel, flux, and carbonaceous solid waste. The ferrous oxide content of the sintered ore is controlled by adjusting the fuel particle size and moisture content, and by controlling the amount of fuel added. The basicity of the sintered ore is controlled by controlling the quality of the flux raw materials and adjusting the flux raw material ratio. The fuel is sintered anthracite, and the flux raw materials include a combination of quicklime, dolomite, and limestone. The method includes the following measures:

[0030] (1) By mass percentage, the content of fuel particles with a particle size ≤3mm in the fuel shall be controlled at 80.0% ± 2%;

[0031] (2) The sintered anthracite is piled into a coal pile with a height of not less than 10.5m. When using the coal pile, the sintered anthracite is taken from the pile. When taking the coal, the bottom layer of coal with a height of 0.6m is left. Only the coal layer with a height of more than 0.6m is taken, thereby controlling the moisture content of the fuel to be 9.0%±1.0%.

[0032] (3) Adjust the fuel ratio using the three-level adjustment method, analyze the ferrous oxide content and its changing trend in the first 3-5 batches of sinter, and calculate the deviation of the current actual ferrous oxide content of the sinter from the target ferrous oxide content. If the actual ferrous oxide content is lower than the target ferrous oxide content, increase the fuel ratio; otherwise, decrease the fuel ratio. If the deviation is ≤0.2%, the corresponding increase or decrease is 0.03% in the fuel ratio. If 0.2% < deviation ≤0.5%, the corresponding increase or decrease is 0.06% in the fuel ratio. If the deviation is >0.5%, the corresponding increase or decrease is 0.1% in the fuel ratio.

[0033] (4) The quality of flux raw materials is controlled by controlling the particle size, moisture content and effective component content of the flux. By mass percentage, the content of particles with a particle size ≤3mm in the flux is controlled to be ≥98%, and the moisture content is <5%. Among them, the CaO content of quicklime is 82%±2%, and the SiO2 content is ≤3.5%. The CaO content of dolomite is ≥30%, the MgO content is ≥19%, and the SiO2 content is ≤2.5%. The CaO content of limestone is ≥51%, and the SiO2 content is ≤2.5%. The CaO and SiO2 content of quicklime are controlled by the combination of high and low quality raw ores and by controlling the kiln temperature of the lime kiln. The CaO, MgO and SiO2 content of dolomite and the CaO and SiO2 content of limestone are controlled by the combination of high and low quality raw ores.

[0034] (5) Establish a flux ratio adjustment coefficient. When the effective components of the flux change, adjust the flux raw material ratio by combining the flux ratio adjustment coefficient with the actual required alkalinity. The ratio is expressed as a mass percentage:

[0035] A 1% increase in CaO content in quicklime leads to a 0.015% increase in the basicity of sintered ore.

[0036] A 1% increase in CaO content in limestone leads to a 0.010% increase in the basicity of sintered ore.

[0037] A 1% increase in SiO2 content in quicklime leads to a 0.020% decrease in the basicity of sintered ore.

[0038] A 1% increase in SiO2 content in limestone leads to a 0.012% decrease in the basicity of sintered ore.

[0039] A 1% increase in SiO2 content in dolomite leads to a 0.020% decrease in the basicity of sintered ore.

[0040] A 1% increase in the total SiO2 content in the flux resulted in a 0.030% decrease in the basicity of the sinter.

[0041] Increasing the quicklime ratio by 0.05% increases the basicity of sinter by 0.01%.

[0042] (6) Carbon-containing solid waste is piled and added using the BLOCK method; carbon-containing solid waste includes gravity ash and coking ash. Gravity ash and coking ash are piled and added separately. The addition rate of gravity ash is 38±2t / h and the addition rate of coking ash is 8±1t / h.

[0043] Although the present invention has been described in detail by way of preferred embodiments, the present invention is not limited thereto. Various equivalent modifications or substitutions can be made to the embodiments of the present invention by those skilled in the art without departing from the spirit and essence of the invention, and such modifications or substitutions should all be within the scope of the present invention. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should also be covered within the protection scope of the present invention.

Claims

1. A control method for stabilizing the quality of sinter, the sinter being produced by sintering a sinter raw material mixture, the sinter raw material mixture comprising an iron-containing ore powder, a fuel, and a flux, characterized by, The content of ferrous oxide in the sintered ore is controlled by controlling the fuel particle size and water content and adjusting the fuel addition amount, and the sintered ore alkalinity is controlled by controlling the quality of the flux raw material and adjusting the flux raw material ratio; the fuel is sintered anthracite, and the flux raw material includes quicklime, dolomite and limestone; In the fuel, the content of fuel particles with a particle size of ≤3 mm is controlled to be 80.0%±2% by mass percentage; The water content of the fuel is controlled to be 9.0%±1.0% by mass percentage; The specific measures for controlling the water content of the fuel are to stack the sintered anthracite into a coal pile with a height of not less than 10.5 m, and to take the sintered anthracite from the stacked coal pile, leaving a 0.6 m high bottom layer of coal, and only taking the coal layer with a height of more than 0.6 m; The fuel addition amount is adjusted by a three-grade adjustment method, and the specific operation is as follows: the content and variation trend of ferrous oxide in the previous 3-5 batches of sintered ore are analyzed, and the deviation of the actual content of ferrous oxide in the sintered ore from the target content of ferrous oxide is calculated; if the actual content of ferrous oxide is lower than the target content of ferrous oxide, the fuel ratio is increased, and vice versa; if the deviation is ≤0.2%, the fuel ratio is increased or decreased by 0.03%; if 0.2%<deviation≤0.5%, the fuel ratio is increased or decreased by 0.06%; if the deviation is >0.5%, the fuel ratio is increased or decreased by 0.1%; The quality of the flux raw material is controlled by controlling the particle size, water content and effective component content of the flux, and the content of particles with a particle size of ≤3 mm in the flux is controlled to be ≥98% by mass percentage, the water content is controlled to be <5%, the CaO content of the quicklime is controlled to be 82%±2% and the SiO2 content is controlled to be ≤3.5%, the CaO content of the dolomite is controlled to be ≥30%, the MgO content is controlled to be ≥19% and the SiO2 content is controlled to be ≤2.5%, and the CaO content of the limestone is controlled to be ≥51% and the SiO2 content is controlled to be ≤2.5%; An adjustment coefficient of the flux ratio is established, and when the effective component of the flux changes, the adjustment coefficient of the flux ratio is combined with the actual required alkalinity to adjust the flux raw material ratio, and the CaO content of the quicklime is controlled to be 82%±2% by mass percentage, the CaO content of the dolomite is controlled to be ≥30%, the MgO content is controlled to be ≥19% and the SiO2 content is controlled to be ≤2.5%, the CaO content of the limestone is controlled to be ≥51% and the SiO2 content is controlled to be ≤2.5%, and the total SiO2 content of the flux is controlled to be ≤5% by mass percentage; If the CaO content of the quicklime increases by 1%, the alkalinity of the sintered ore increases by 0.015%; If the CaO content of the limestone increases by 1%, the alkalinity of the sintered ore increases by 0.010%; If the SiO2 content of the quicklime increases by 1%, the alkalinity of the sintered ore decreases by 0.020%; If the SiO2 content of the limestone increases by 1%, the alkalinity of the sintered ore decreases by 0.012%; If the SiO2 content of the dolomite increases by 1%, the alkalinity of the sintered ore decreases by 0.020%; If the total SiO2 content of the flux increases by 1%, the alkalinity of the sintered ore decreases by 0.030%; If the quicklime ratio increases by 0.05%, the alkalinity of the sintered ore increases by 0.01%.

2. The control method according to claim 1, characterized by, The target content of ferrous oxide in the sintered ore is 9.0%-10.0%.

3. The control method according to claim 1, characterized by, The CaO and SiO2 contents of the quicklime are controlled by matching high and low quality raw materials and controlling the kiln temperature of the lime kiln, the CaO, MgO and SiO2 contents of the dolomite are controlled by matching high and low quality raw materials, and the CaO and SiO2 contents of the limestone are controlled by matching high and low quality raw materials.

4. The control method according to claim 1, characterized by, The sintering raw material further comprises carbon-containing solid waste, the carbon-containing solid waste is stacked and added by BLOCK stacking method; the carbon-containing solid waste comprises gravity ash and coking ash, the gravity ash and the coking ash are respectively stacked and added, wherein the adding speed of the gravity ash is 38±2 t / h, and the adding speed of the coking ash is 8±1 t / h.