A method of determining the quality of lime

Abstract

The present application relates to a kind of methods for judging lime quality, the method includes the following steps: (1) the uniform filling of lime block ten grid tank, then pour out and carry out crushing treatment;The calcination degree of lime block is judged by the sound of crushing and the appearance of lime block in the process of crushing treatment, obtain normal burning lime block, green burning lime block and overburning lime block;(2)the normal burning lime block, green burning lime block and overburning lime block obtained in step (1) are independently filled into ten grid tank respectively, and the proportion of green burning lime block in the total amount of lime block is obtained;According to the proportion, the ignition loss of lime is calculated;(3) take the normal burning lime block, green burning lime block and overburning lime block in step (2) and carry out water immersion treatment, and the activity degree of lime block is judged by hydration time.The present application uses ten grid method and water immersion method to quickly judge the quality of lime, realizes the pre-control of production.

Description

Technical Field

[0001] This invention relates to the field of lime quality testing technology, and specifically to a method for determining lime quality. Background Technology

[0002] Lime is obtained by calcining limestone at a high temperature of 900-1100℃. The main component of limestone is calcium carbonate, which decomposes into calcium oxide and carbon dioxide after high-temperature calcination. The main component of lime is calcium oxide. In actual production, the quality of lime produced is uneven due to factors such as unreasonable temperature distribution inside the production equipment, uneven limestone particle size, and variations in high-temperature time.

[0003] The main quality control indicators for lime are loss on ignition and activity. The direct factors affecting these two indicators are the degree of ignition of the lime, namely, normal burning, underburning, and overburning. Normal burning means that calcium carbonate is fully decomposed, resulting in lime with a loose structure and high activity. Underburning means that some undecomposed calcium carbonate remains in the lime. Overburning means that the local temperature is too high and the high temperature time is too long, resulting in a dense lime structure and reduced activity. Both underburning and overburning will reduce the quality of the lime.

[0004] Currently, the testing of lime quality typically requires the preparation of lime process test samples, which are then sent for precise testing. However, it takes 6-8 hours from sample preparation and delivery to the output of test data, resulting in a delay in data guidance for production. Furthermore, the samples taken may not be representative, leading to wasted time, manpower, and resources in preparing new samples.

[0005] CN 116179795A discloses a method and application for judging or solving the problem of lime underburning and overburning during steel refining. The method includes turning on argon gas for stirring after molten steel enters the ladle refining furnace, followed by power supply and slag addition. Underburning is indicated by the appearance of yellow smoke during slag addition and power supply, or by the sound of lime lumps striking the electrodes during power supply. After power supply and slag addition, the molten steel is refined. If the slag on the surface of the molten steel is glass slag during refining, lime is added for further refining. Overburning is indicated when the ratio of lime to fluxing agent added during refining is greater than (3-4):1. However, this method can only determine the quality of lime during steel refining and cannot pre-judge the quality of lime at the production source.

[0006] CN 113504146A discloses a method for detecting under-burning and over-burning of quicklime, comprising the following steps: weighing a quicklime sample and placing it in a glass container, pouring distilled water into the container, slowly pouring out the gelatinous liquid from the top of the container after digestion, while avoiding overflow of the sediment at the bottom; removing all the sediment from the container and drying it in a drying oven to constant weight, then weighing the dried sample; preparing a component sample according to requirements after weighing, and sending the component sample to a laboratory for chemical analysis to obtain the percentage content of under-burning and over-burning quicklime. This method can accurately calculate the percentage content of under-burning and over-burning quicklime, but it is not applicable to situations where quick determination of lime quality is required in on-site production.

[0007] Therefore, in view of the shortcomings of existing technologies, there is a need to provide a method that can accurately and quickly determine the quality of lime. Summary of the Invention

[0008] The purpose of this invention is to provide a method for judging the quality of lime. The method involves quickly dividing the lime into ten-grid samples after crushing and calculating the loss on ignition. The water immersion method is used to determine the hydration status of the lime blocks, thereby achieving a rapid judgment of lime quality and providing guidance for production in conjunction with production practice.

[0009] To achieve this objective, the present invention adopts the following technical solution:

[0010] This invention provides a method for determining the quality of lime, the method comprising the following steps:

[0011] (1) Fill the ten-compartment trough with lime blocks evenly, and then pour them out for crushing. During the crushing process, the degree of calcination of the lime blocks is judged by the sound of crushing and the appearance of the lime blocks, and the normal calcination lime blocks, the under-calcined lime blocks and the over-calcined lime blocks are obtained.

[0012] (2) Fill the calcined lime blocks, raw lime blocks and over-burned lime blocks obtained in step (1) into the ten-compartment trough separately to obtain the proportion of the raw lime blocks in the total amount of lime blocks; calculate the ignition loss of lime based on the proportion.

[0013] (3) Take the lithi block, scalded lime block and over-burned lime block from step (2) and immerse them in water to determine the activity of the lime block by the hydration time.

[0014] The method for judging lime quality provided by this invention uses a simple crushing process followed by rapid sampling using a ten-grid method to compare under-burned, over-burned, and normally-burned lime. The loss on ignition is calculated by using the proportion of under-burned lime blocks in the total lime block volume. Furthermore, a water immersion method is used to determine the hydration time of lime blocks at different calcination levels, thereby judging the activity of the lime blocks. This method enables rapid judgment of lime quality and, combined with production practice, provides guidance for production, timely and accurate prevention of accidents and detection of problems, achieving proactive control. Simultaneously, it avoids the adverse effects of delayed test data, laying the foundation for stable kiln condition control.

[0015] The reasons for choosing the ten-compartment trough are mainly as follows: 1. It is convenient for calculation; 2. Only one person is needed to complete the entire process of judging the quality of lime; 3. The ten-compartment trough meets the sampling standards for blocky materials.

[0016] Preferably, the mass of the lime block in step (1) is 4-6 kg, for example, it can be 4 kg, 4.5 kg, 5 kg, 5.5 kg or 6 kg, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0017] The mass of the lime blocks is the amount required to evenly fill the ten-compartment trough. If the mass is too large, it cannot be completely filled into the ten-compartment trough; if the mass is too small, it cannot be completely filled into the ten-compartment trough. This will lead to deviations in the calculation of the proportion of raw lime blocks in the subsequent calculation.

[0018] Preferably, the ten-compartment trough in step (1) comprises ten metal troughs.

[0019] The ten-compartment metal trough is a self-made metal trough with ten identical compartments. The specific material of the metal trough is not limited in this invention.

[0020] Preferably, the crushing process in step (1) includes hammer crushing.

[0021] Preferably, the crushing process in step (1) results in a lime block particle size of <20mm, for example, 18mm, 15mm, 12mm, 10mm or 8mm, but not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0022] The crushing process to a lime block particle size of <20mm facilitates the separation of raw lime blocks and subsequent filling of the ten-compartment trough. If the lime block particle size is too large, the calculation of the proportion of raw lime blocks will be inaccurate, and it will also be detrimental to the subsequent filling of the ten-compartment trough.

[0023] Preferably, the lime block in step (1) has a dull breaking sound, a white outer skin, a limestone-colored center, and a hard texture, and is a raw lime block.

[0024] Preferably, the lime block in step (1) has a crisp breaking sound, is white in color, and has a soft texture, and is a positively burned lime block.

[0025] Preferably, the sound of the breaking in step (1) is dull, the color of the lime block is black or yellow, and the texture of the lime block is hard, and the lime block is an overburned lime block.

[0026] Distinguishing the degree of calcination of lime blocks by judging the sound of breaking them is simple, easy, and quick, facilitating rapid inspection on the production site. Distinguishing the degree of calcination of lime blocks by judging their color is also simple, easy, and quick. Combining this with the sound of breaking them further improves the efficiency of on-site inspection.

[0027] Preferably, the filling of the ten-compartment trough in step (2) is done using a metal shovel.

[0028] Preferably, the reduction in step (2) is the product of the proportion of raw lime blocks in the total amount of lime blocks and a specific coefficient.

[0029] Preferably, the value of the specific coefficient is 0.5.

[0030] The specific coefficient is derived from production experience. First, by calculating the proportion of raw lime blocks in the total amount of lime blocks and multiplying it by the specific coefficient of 0.5, the lime ignition loss can be obtained accurately and quickly. A relatively low lime ignition loss indicates better lime quality.

[0031] Preferably, the water immersion treatment in step (3) is carried out in a metal water tank.

[0032] Preferably, the method for judging the activity of the lime block in step (3) specifically includes: if the hydration end time is <10s and the hydration reaction is vigorous, the activity of the lime block is ≥300mL / 50g; if the hydration end time is 10-20s and the hydration reaction is slow, the activity of the lime block is 250-300mL / 50g; if the hydration start time is >20s or no hydration occurs, the activity of the lime block is <250mL / 50g.

[0033] The hydration completion time is <10s, for example, it can be 8s, 6s or 4s, but it is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0034] The activity of the lime block is ≥300mL / 50g, for example, it can be 300mL / 50g, 350mL / 50g or 400mL / 50g, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0035] The hydration end time is 10-20 seconds, for example, it can be 10 seconds, 15 seconds or 20 seconds, but it is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0036] The activity of lime blocks is 250-300mL / 50g, for example, it can be 250mL / 50g, 280mL / 50g or 300mL / 50g, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0037] The hydration start time is greater than 20 seconds, for example, it can be 22 seconds, 25 seconds or 28 seconds, but it is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0038] The activity of lime blocks is <250mL / 50g, for example, it can be 240mL / 50g, 220mL / 50g or 200mL / 50g, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0039] Preferably, the total time used for steps (1), (2) and (3) is 10-15 minutes, for example, 10 minutes, 11 minutes, 12 minutes, 14 minutes or 15 minutes, but not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0040] As a preferred technical solution of the method described in this invention, the method includes the following steps:

[0041] (1) Fill the ten-compartment metal trough evenly with lime blocks weighing 4-6 kg, then pour them out and crush them with a hammer until the particle size of the lime blocks is <20 mm; during the crushing process, the degree of calcination of the lime blocks is judged by the sound of crushing and the color of the lime blocks to obtain normally calcined lime blocks, under-calcined lime blocks and over-calcined lime blocks.

[0042] The following are descriptions of lime blocks: A dull breaking sound, a white outer layer, a limestone-colored center, and a hard texture indicate that the lime block is underburned; a crisp breaking sound, a white color, and a soft texture indicate that the lime block is properly burned; and a dull breaking sound, a black or yellow color, and a hard texture indicate that the lime block is overburned.

[0043] (2) Using a metal shovel, the lit lime blocks, scalded lime blocks and over-burned lime blocks obtained in step (1) are separately filled into a ten-compartment metal trough to obtain the proportion of the scalded lime blocks in the total amount of lime blocks; the reduction in lime ignition is calculated based on the product of the proportion and a specific coefficient.

[0044] (3) Take the lithi lime blocks, scalded lime blocks and over-burned lime blocks from step (2) and immerse them in a metal water tank. The activity of the lime blocks is determined by the hydration time. The specific methods for determining the activity of the lime blocks include: if the hydration end time is <10s and the hydration reaction is vigorous, the activity of the lime blocks is ≥300mL / 50g; if the hydration end time is 10-20s and the hydration reaction is slow, the activity of the lime blocks is 250-300mL / 50g; if the hydration start time is >20s or no hydration occurs, the activity of the lime blocks is <250mL / 50g.

[0045] The total time taken for steps (1), (2) and (3) is 10-15 minutes.

[0046] Compared with the prior art, the present invention has the following beneficial effects:

[0047] The method for judging lime quality provided by this invention uses a simple crushing process followed by rapid sampling using a ten-grid method to compare under-burned, over-burned, and normally-burned lime. The loss on ignition is calculated by using the proportion of under-burned lime blocks in the total lime block volume. Furthermore, a water immersion method is used to determine the hydration time and degree of hydration of lime blocks at different calcination levels, thereby judging the activity of the lime blocks. This method enables rapid judgment of lime quality in just 10-15 minutes. Combined with practical production guidance, it can promptly and accurately prevent accidents and identify problems, achieving proactive control. It also avoids the adverse effects of delayed inspection data, laying the foundation for stable kiln condition control. This method achieves a 10% increase in production beyond design capacity, with steelmaking lime consumption below 32 kg per ton of steel. The method is simple and easy to implement, not limited by site or time, and can also be applied to the rapid acceptance of lime quality. Detailed Implementation

[0048] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0049] Example 1

[0050] This embodiment provides a method for determining the quality of lime, the method comprising the following steps:

[0051] (1) Fill the ten-compartment metal trough evenly with 5kg of lime blocks, then pour them out and crush them with a hammer until the average particle size of the lime blocks is 12mm; during the crushing process, the degree of calcination of the lime blocks is judged by the sound of crushing and the color of the lime blocks, and the positively calcined lime blocks, the under-calcined lime blocks and the over-calcined lime blocks are obtained.

[0052] The following are descriptions of lime blocks: A dull breaking sound, a white outer layer, a limestone-colored center, and a hard texture indicate that the lime block is underburned; a crisp breaking sound, a white color, and a soft texture indicate that the lime block is properly burned; and a dull breaking sound, a black or yellow color, and a hard texture indicate that the lime block is overburned.

[0053] (2) Using a metal shovel, the lit lime blocks, scalded lime blocks and over-burned lime blocks obtained in step (1) are separately filled into a ten-compartment metal trough, so that the proportion of the scalded lime blocks in the total amount of lime blocks is 10%. The ignition loss of the lime is calculated to be 5% based on the product of the proportion and a specific coefficient; the value of the specific coefficient is 0.5.

[0054] (3) Take the positively burned lime blocks, the raw lime blocks and the overburned lime blocks from step (2) and immerse them in a metal water tank. The hydration time of the positively burned lime blocks is 4s and the hydration reaction is vigorous, with an activity of 400mL / 50g. The hydration time of the raw lime blocks is 10s and the hydration reaction is slow, with an activity of 300mL / 50g. The hydration time of the overburned lime blocks is 22s and the activity is 240mL / 50g.

[0055] In this embodiment, the ignition loss and activity of the lime block are obtained by calculation and judgment. At the same time, the total time used for steps (1), (2) and (3) is 10 minutes, which realizes efficient and accurate judgment of the quality of the lime block.

[0056] Example 2

[0057] This embodiment provides a method for determining the quality of lime, the method comprising the following steps:

[0058] (1) Fill the ten-compartment metal trough with 4kg of lime blocks evenly, then pour them out and crush them with a hammer until the average particle size of the lime blocks is 10mm; during the crushing process, the degree of calcination of the lime blocks is judged by the sound of crushing and the color of the lime blocks, and the normal-burned lime blocks, the underburned lime blocks and the overburned lime blocks are obtained.

[0059] The following are descriptions of lime blocks: A dull breaking sound, a white outer layer, a limestone-colored center, and a hard texture indicate that the lime block is underburned; a crisp breaking sound, a white color, and a soft texture indicate that the lime block is properly burned; and a dull breaking sound, a black or yellow color, and a hard texture indicate that the lime block is overburned.

[0060] (2) Using a metal shovel, the lit lime blocks, scalded lime blocks and over-burned lime blocks obtained in step (1) are separately filled into a ten-compartment metal trough, so that the proportion of the scalded lime blocks in the total amount of lime blocks is 10%. The ignition loss of the lime is calculated to be 5% based on the product of the proportion and a specific coefficient; the value of the specific coefficient is 0.5.

[0061] (3) Take the positively burned lime blocks, the raw lime blocks and the overburned lime blocks from step (2) and immerse them in a metal water tank. The hydration time of the positively burned lime blocks is 6s and the hydration reaction is vigorous, with an activity of 350mL / 50g; the hydration time of the raw lime blocks is 15s and the hydration reaction is slow, with an activity of 280mL / 50g; the hydration time of the overburned lime blocks is 25s and the activity is 220mL / 50g.

[0062] In this embodiment, the ignition loss and activity of the lime block are obtained by calculation and judgment. At the same time, the total time used for steps (1), (2) and (3) is 12 minutes, which realizes the efficient and accurate judgment of the quality of the lime block.

[0063] Example 3

[0064] This embodiment provides a method for determining the quality of lime, the method comprising the following steps:

[0065] (1) Fill the ten-compartment metal trough with 6kg of lime blocks evenly, then pour them out and crush them with a hammer until the average particle size of the lime blocks is 18mm; during the crushing process, the degree of calcination of the lime blocks is judged by the sound of crushing and the color of the lime blocks, and the normal-burned lime blocks, the underburned lime blocks and the overburned lime blocks are obtained.

[0066] The following are descriptions of lime blocks: A dull breaking sound, a white outer layer, a limestone-colored center, and a hard texture indicate that the lime block is underburned; a crisp breaking sound, a white color, and a soft texture indicate that the lime block is properly burned; and a dull breaking sound, a black or yellow color, and a hard texture indicate that the lime block is overburned.

[0067] (2) Using a metal shovel, the lit lime blocks, scalded lime blocks and over-burned lime blocks obtained in step (1) are separately filled into a ten-compartment metal trough, so that the proportion of the scalded lime blocks in the total amount of lime blocks is 10%. The ignition loss of the lime is calculated to be 5% based on the product of the proportion and a specific coefficient; the value of the specific coefficient is 0.5.

[0068] (3) Take the positively burned lime blocks, the raw lime blocks and the overburned lime blocks from step (2) and immerse them in a metal water tank. The hydration time of the positively burned lime blocks is 8s and the hydration reaction is vigorous, with an activity of 300mL / 50g. The hydration time of the raw lime blocks is 20s and the hydration reaction is slow, with an activity of 250mL / 50g. The hydration time of the overburned lime blocks is 28s and the activity is 200mL / 50g.

[0069] In this embodiment, the ignition loss and activity of the lime block are obtained by calculation and judgment. At the same time, the total time used for steps (1), (2) and (3) is 15 minutes, which realizes efficient and accurate judgment of the quality of the lime block.

[0070] Example 4

[0071] This embodiment provides a method for judging the quality of lime. The difference from Embodiment 1 is that the average particle size of the lime block in step (1) is adjusted to 23mm, while the rest is the same as in Embodiment 1.

[0072] In this embodiment, the ignition loss and activity of the lime block are obtained by calculation and judgment. The accuracy is lower than that of Example 1. This is because the crushed particles are too large, which makes it impossible to completely separate the raw lime block, thus reducing the accuracy of the proportion calculation and hydration rate judgment. The total time used for steps (1), (2) and (3) is 14 minutes, which is not much different from that of Example 1.

[0073] Example 5

[0074] This embodiment provides a method for judging the quality of lime. The difference from Embodiment 1 is that, except for adjusting the value of the specific coefficient in step (2) to 0.3, everything else is the same as in Embodiment 1.

[0075] In this embodiment, the accuracy of the ignition loss of the lime block obtained by calculation is lower than that of Example 1. This is because the selection of a specific coefficient is biased, which reduces the accuracy of the ignition loss calculation. The total time used for steps (1), (2) and (3) is 11 minutes, which is not much different from that of Example 1.

[0076] Example 6

[0077] This embodiment provides a method for judging the quality of lime. The difference from Embodiment 1 is that, except for adjusting the value of the specific coefficient in step (2) to 0.8, the rest is the same as in Embodiment 1.

[0078] In this embodiment, the accuracy of the ignition loss of the lime block obtained by calculation is lower than that of Example 1. This is because the selection of a specific coefficient is biased, which reduces the accuracy of the ignition loss calculation. The total time used for steps (1), (2) and (3) is 13 minutes, which is not much different from that of Example 1.

[0079] Comparative Example 1

[0080] This comparative example provides a method for judging the quality of lime. After preparing lime blocks, the loss on ignition and activity are tested according to GB / T3286.8-2014 and YB / T105-2014.

[0081] The lime activity calculated in this comparative example is slightly more accurate than that in Example 1, but it took 7 hours. The data is not used to guide production and cannot achieve rapid quality judgment on the production site.

[0082] Comparative Example 2

[0083] This comparative example provides a method for judging the quality of lime. The difference from Example 1 is that the water immersion treatment in step (3) is changed to hydrochloric acid titration treatment. After the lime is dissolved in water, phenolphthalein solution is added dropwise, and 4g equivalent hydrochloric acid is used for titration for 5 minutes. The rest is the same as in Example 1.

[0084] The lime activity calculated in this comparative example is not significantly different from that in Example 1. However, the hydrochloric acid titration process requires a large amount of reagents and is complex and time-consuming, which is not conducive to rapid quality judgment on the production site.

[0085] In summary, the method for judging lime quality provided by this invention, through simple crushing and rapid sampling using the ten-grid method, allows for the comparison of under-burned, over-burned, and normally-burned lime. The loss on ignition is calculated by using the proportion of under-burned lime blocks in the total lime block volume. Furthermore, the water immersion method is used to determine the hydration time and degree of hydration of lime blocks at different calcination levels, thereby judging the activity of the lime blocks. This enables rapid judgment of lime quality and, combined with production practice, provides guidance for production, timely and accurate prevention of accidents and detection of problems, achieving proactive control. It also avoids the adverse effects of delayed inspection data, laying the foundation for stable kiln condition control, achieving a 10% increase in production beyond design capacity, and reducing steelmaking lime consumption to below 32 kg per ton of steel. The method is simple and easy to implement, not limited by site or time, and can also be applied to the rapid acceptance of lime quality.

[0086] The above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A method for determining the quality of lime, characterized in that, The method includes the following steps: (1) Fill the ten-compartment trough with lime blocks evenly, and then pour them out for crushing. During the crushing process, the degree of calcination of the lime blocks is judged by the sound of crushing and the appearance of the lime blocks to obtain positively calcined lime blocks, under-calcined lime blocks and over-calcined lime blocks. The crushing process is carried out until the particle size of the lime blocks is <20mm. (2) Fill the positively burned lime blocks, the raw lime blocks and the overburned lime blocks obtained in step (1) into the ten-compartment trough separately to obtain the proportion of the raw lime blocks in the total amount of lime blocks; calculate the ignition loss of lime based on the proportion; the ignition loss is the product of the proportion of the raw lime blocks in the total amount of lime blocks and a specific coefficient; the value of the specific coefficient is 0.5; (3) Take the lithi lime blocks, scalded lime blocks and over-burned lime blocks from step (2) and immerse them in water to determine the activity of the lime blocks by the hydration time; The specific methods for determining the activity of the lime block include: if the hydration end time is <10s and the hydration reaction is vigorous, the activity of the lime block is ≥300mL / 50g; if the hydration end time is 10-20s and the hydration reaction is slow, the activity of the lime block is 250-300mL / 50g; if the hydration start time is >20s or there is no hydration, the activity of the lime block is <250mL / 50g.

2. The method according to claim 1, characterized in that, The mass of the lime block in step (1) is 4-6 kg.

3. The method according to claim 1, characterized in that, Step (1) The ten-compartment trough body includes ten metal troughs.

4. The method according to claim 1, characterized in that, The crushing process in step (1) includes hammer crushing.

5. The method according to claim 1, characterized in that, The sound of the broken lime in step (1) is dull, the color of the lime block is white on the outside and limestone in the center, and the lime block is hard in texture. The lime block is a raw lime block.

6. The method according to claim 1, characterized in that, The sound of breaking in step (1) is crisp, the color of the lime block is white and the texture of the lime block is soft, and the lime block is a lithiated lime block.

7. The method according to claim 1, characterized in that, The sound of the broken lime in step (1) is dull, the color of the lime block is black or yellow and the texture of the lime block is hard, and the lime block is an overburned lime block.

8. The method according to claim 1, characterized in that, The water immersion treatment in step (3) is carried out in a metal water tank.

9. The method according to claim 1, characterized in that, The total time taken for steps (1), (2) and (3) is 10-15 minutes.