A method for evaluating the drying effect of lump ore

Abstract

This invention relates to a method for evaluating the drying effect of lump ore, belonging to the field of preliminary treatment technology for promoting the drying of solid materials or products. The method first measures the temperature of an initial mass of undried lump ore, then dries the undried lump ore and measures its mass, then screens the dried lump ore and measures its mass, and finally crushes the screened lump ore to obtain its bursting temperature. The moisture content and powder content of the lump ore are calculated based on the mass changes at different stages. At the actual drying discharge port, twice the initial mass of dried lump ore is taken and divided into two equal portions. The temperature of the first portion is measured after crushing, and the mass of the second portion is measured after drying and then screened. The moisture content and powder content of the second portion are calculated. Finally, the lump ore drying index is calculated based on the difference between the hot air temperature and the bursting temperature of the actual drying line, the dehydration rate ratio, the difference in powder content between the two drying processes, and the difference between the temperature after crushing and the temperature of the undried lump ore. The closer the drying index is to 10, the better the drying effect.

Description

Technical Field

[0001] This invention relates to a method for evaluating the drying effect of lump ore, belonging to the technical field of preliminary treatment for promoting the drying of solid materials or products (F26B1 / 00). Background Technology

[0002] Currently, the main raw materials fed into blast furnaces include sinter, pellets, and lump ore. Compared with sinter and pellets, lump ore does not require high-temperature treatment and can be used directly, offering higher environmental friendliness and cost-effectiveness. Increasing the proportion of lump ore in the furnace charge is an effective measure to shorten the process flow, reduce environmental pollution, stabilize blast furnace operation, and reduce production costs.

[0003] However, lump ore requires extensive water spraying during transportation to suppress dust, leading to increased moisture content. High-moisture lump ore entering the blast furnace reduces the permeability of the charge column, affecting the stable operation of the blast furnace. To address these issues, belt dryers are commonly used in China for pre-treatment of lump ore. However, the goethite content in lump ore used in domestic blast furnaces is relatively high, requiring strict control of the drying heat gas temperature during the drying process. If the drying heat gas temperature is too high, it can cause the lump ore to crack and produce new powder; conversely, if the drying heat gas temperature is too low, it cannot effectively remove moisture, still affecting the stable operation of the blast furnace.

[0004] Therefore, there is an urgent need for an effective method to evaluate the drying effect of lump ore, so as to adjust the hot air temperature of the belt dryer, thereby improving the drying effect of lump ore and reducing economic losses. Summary of the Invention

[0005] The technical problem to be solved by this invention is: how to evaluate the drying effect of lump ore.

[0006] The technical solution proposed by this invention to solve the above-mentioned technical problems is: a method for evaluating the drying effect of lump ore, comprising the following steps:

[0007] Step 1: Take a mass m1 of undried ore and measure the temperature t1 of the undried ore;

[0008] Step 2: Dry the undried lump ore at a temperature t2 for a drying time of s, and measure the mass m2 of the dried lump ore.

[0009] Step 3: Screen the dried ore from Step 2 and measure the mass m3 of the screened ore.

[0010] Step 4: Crush the ore after screening in Step 3 into ore powder, heat the ore powder to obtain a differential thermal curve, and take the endothermic peak temperature between 250°C and 450°C in the differential thermal curve as the ore bursting temperature t3.

[0011] Step 5: Calculate the moisture content of the lump ore using the following formula (1).

[0012] (1);

[0013] The powder ratio of lump ore is calculated according to formula (2).

[0014] (2);

[0015] Step 6: After the lump ore is dried at a hot air temperature of t5 in the actual drying production line, take twice the mass of dried lump ore m1 from the discharge port of the actual drying production line and divide it into a first lump ore m1 and a second lump ore m1 of equal mass.

[0016] Step 6.1: Crush the first lump ore m1 and measure the temperature t4 after crushing;

[0017] Step 6.2: Dry the second lump ore m1 at temperature t2 for a drying time of s, and measure the mass m4 of the second lump ore after drying;

[0018] The dried second portion of lump ore was screened, and the mass m5 of the screened second portion of lump ore was measured.

[0019] Step 6.3: Calculate the moisture content of the second lump ore using the following formula (3).

[0020] (3);

[0021] The powder ratio of the second lump ore is calculated according to formula (4).

[0022] (4);

[0023] Step 7: Based on the different hot air temperatures t5 in the actual drying production line, calculate the difference between the different hot air temperatures t5 and the bursting temperature t3. Dehydration ratio Powder ratio difference The difference between the temperature t4 after crushing and the temperature t1 of the undried lump ore. ;

[0024] The independent variable matrix X is constructed using the differences between different hot air temperatures t5 and burst temperatures t3, the dehydration rate ratio, the powder rate difference, and the difference between the temperature t4 after crushing and the temperature t1 of the undried lump ore; the objective variable matrix Y is constructed using the historical scores in the historical reports of lump ore drying effects under different hot air temperatures t5.

[0025] The difference is calculated using the following formula (5). The weight matrix C consists of the weight λ1 of the weight, the weight λ2 of the dehydration ratio, the weight λ3 of the powder ratio difference, and the weight λ4 of the difference t4 and t1.

[0026] (5);

[0027] In equation (5), T is the matrix transpose;

[0028] Step 8: Calculate the drying index of lump ore according to formula (5).

[0029] (6);

[0030] when The closer to 10, the better the drying effect and the better the drying hot air temperature.

[0031] The beneficial effects of this invention are as follows: By measuring the temperature of the dried lump ore sampled from the discharge port after crushing, the temperature difference between the surface and interior of the lump ore is effectively avoided. Furthermore, based on precise calculations of the moisture and powder content of the undried lump ore and the dried lump ore in the actual drying production line, and comprehensively considering key parameters such as the difference between drying hot air temperature and bursting temperature, the dehydration ratio, the powder content difference, and the difference between crushing temperature and undried temperature, a scientific evaluation index is constructed. Combined with historical data and regression analysis, this invention possesses strong adaptability, thus accurately evaluating the drying effect of lump ore at different hot air temperatures. The evaluation method of this invention not only optimizes the selection of drying hot air temperature in the actual production line, improving production efficiency and product quality, but also maximizes economic benefits by reducing energy consumption and production costs. Attached Figure Description

[0032] The present invention will be further described below with reference to the accompanying drawings.

[0033] Figure 1 This is the differential thermal curve of mineral powder in the evaluation method of the drying effect of lump ore in the embodiment. Detailed Implementation

[0034] Example

[0035] This embodiment of a method for evaluating the drying effect of lump ore includes the following steps:

[0036] Step 1: Take 10 kg of undried lump ore with a mass of m1 and measure the temperature of the undried lump ore as t1 = 22℃.

[0037] Step 2: Dry the undried lump ore at a temperature of t2=105℃ for a drying time of s=4h. The mass of the dried lump ore is measured to be m2=9.5kg.

[0038] Step 3: The dried ore from Step 2 is screened, and the mass of the screened ore is measured to be m3 = 8.455 kg.

[0039] Step 4: Crush the ore sieving in Step 3 into ore powder, such as... Figure 1 As shown, the differential thermal curve was obtained by heating the ore powder. The endothermic peak temperature between 250°C and 450°C in the differential thermal curve was taken as the bursting temperature of the lump ore, t3 = 342.3°C.

[0040] Step 5: Calculate the moisture content of the lump ore using the following formula (1).

[0041] (1);

[0042] The powder ratio of lump ore is calculated according to formula (2).

[0043] (2);

[0044] In this embodiment, ω0 = 5% is calculated according to formula (1), and δ0 = 11% is calculated according to formula (2).

[0045] Step 6: After the lump ore is dried at a hot air temperature of t5=500℃ in the actual drying production line, take twice the mass m1 of dried lump ore from the discharge port of the actual drying production line and divide it into a first lump ore m1 and a second lump ore m1 of equal mass.

[0046] Step 6.1: Crush the first piece of ore m1 and measure the temperature after crushing t4 = 100.4℃;

[0047] Step 6.2: Dry the second lump ore m1 at a temperature t2=105℃ for a drying time of s=4h. The mass of the second lump ore after drying is measured to be m4=9.85kg.

[0048] The second batch of dried lump ore was screened, and the mass of the second batch of screened lump ore was measured to be m5 = 8.148 kg.

[0049] Step 6.3: Calculate the moisture content of the second lump ore using the following formula (3).

[0050] (3);

[0051] The powder ratio of the second lump ore is calculated according to formula (4).

[0052] (4);

[0053] In this embodiment, ω1 is calculated to be 1.5% according to formula (3), and δ1 is calculated to be 17.3% according to formula (2).

[0054] Step 7: Based on the different hot air temperatures t5 in the actual drying production line, calculate the difference between the different hot air temperatures t5 and the bursting temperature t3. Dehydration ratio Powder ratio difference The difference between the temperature t4 after crushing and the temperature t1 of the undried lump ore. ;

[0055] The independent variable matrix X is constructed using the differences between different hot air temperatures t5 and burst temperatures t3, the dehydration rate ratio, the powder rate difference, and the difference between the temperature t4 after crushing and the temperature t1 of the undried lump ore; the objective variable matrix Y is constructed using the historical scores in the historical reports of lump ore drying effects under different hot air temperatures t5.

[0056] Calculate the difference using the following formula (5) The weight matrix C consists of the weights λ1 (for the dehydration ratio), λ2 (for the powder ratio difference), λ3 (for the powder ratio difference), and λ4 (for the difference t4 and t1).

[0057] (5);

[0058] In equation (5), T is the matrix transpose;

[0059] In this embodiment, λ1=0.32, λ2=0.30, λ3=0.28, and λ4=0.10 are calculated according to formula (5).

[0060] Step 8: Calculate the drying index of lump ore according to formula (5).

[0061] (6);

[0062] when The closer to 10, the better the drying effect and the better the drying hot air temperature.

[0063] In this embodiment, γ = 8.61 is calculated according to formula (6), indicating that the drying effect is good and the drying hot air temperature is good.

[0064] The above description is only a preferred embodiment of the present invention, but the present invention is not limited thereto. All equivalent substitutions or modifications made to the concepts and technical solutions of the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for evaluating the drying effect of lump ore, characterized in that... Includes the following steps: Step 1: Take a mass m1 of undried ore and measure the temperature t1 of the undried ore; Step 2: Dry the undried lump ore at a temperature t2 for a drying time of s, and measure the mass m2 of the dried lump ore. Step 3: Screen the dried ore from Step 2 and measure the mass m3 of the screened ore. Step 4: Crush the ore after screening in Step 3 into ore powder, heat the ore powder to obtain a differential thermal curve, and take the endothermic peak temperature between 250°C and 450°C in the differential thermal curve as the ore bursting temperature t3. Step 5: Calculate the moisture content of the lump ore using the following formula (1). （1）； The powder ratio of lump ore is calculated according to formula (2). （2）； Step 6: After the lump ore is dried at a hot air temperature of t5 in the actual drying production line, take twice the mass of dried lump ore m1 from the discharge port of the actual drying production line and divide it into a first lump ore m1 and a second lump ore m1 of equal mass. Step 6.1: Crush the first lump ore m1 and measure the temperature t4 after crushing; Step 6.2: Dry the second lump ore m1 at temperature t2 for a drying time of s, and measure the mass m4 of the second lump ore after drying; The dried second portion of lump ore was screened, and the mass m5 of the screened second portion of lump ore was measured. Step 6.3: Calculate the moisture content of the second lump ore using the following formula (3). （3）； The powder ratio of the second lump ore is calculated according to formula (4). （4）； Step 7: Based on the different hot air temperatures t5 in the actual drying production line, calculate the difference between the different hot air temperatures t5 and the bursting temperature t3. Dehydration ratio Powder ratio difference The difference between the temperature t4 after crushing and the temperature t1 of the undried lump ore. ; The independent variable matrix X is constructed using the differences between different hot air temperatures t5 and burst temperatures t3, the dehydration rate ratio, the powder rate difference, and the difference between the temperature t4 after crushing and the temperature t1 of the undried lump ore; the objective variable matrix Y is constructed using the historical scores in the historical reports of lump ore drying effects under different hot air temperatures t5. The difference is calculated using the following formula (5). The weight matrix C consists of the weight λ1 of the weight, the weight λ2 of the dehydration ratio, the weight λ3 of the powder ratio difference, and the weight λ4 of the difference t4 and t1. (5)； In equation (5), T is the matrix transpose; Step 8: Calculate the drying index of lump ore according to formula (5). （6）； when The closer to 10, the better the drying effect and the better the drying hot air temperature.

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