An evaluation method for mixing effect of field mixed ammonium nitrate fuel oil explosive and a raw material inspection method

Abstract

The application discloses a kind of field mixed loading granular ammonium oil-based explosive mixing effect evaluation method and raw material inspection method, and mixing effect evaluation method includes using field mixed loading equipment, by adding dyeing agent in oil phase material and under normal production conditions, by dyed oil phase material and porous granular ammonium nitrate are mixed and stirred, and ensure that part of granular material is not dyed, then random collection after mixing field sample;By statistical analysis and calculation, obtain the percentage of dyed and undyed porous granular ammonium nitrate in the sample amount, and one of the ratios is defined as the evaluation index of mixing effect.The raw material inspection method verifies the conformity by means of the evaluation index when any raw material is changed through laboratory reproduction method, thereby indirectly judging the availability of raw materials.The beneficial effects of the present application are that the mixing effect is quantitatively evaluated, which can quickly and reliably indicate production;The eligibility of raw materials is implemented based on the quantitative evaluation index of mixing effect, and the detection result is accurate and reliable.

Description

Technical Field

[0001] This invention relates to laboratory preparation techniques for porous granular ammonium nitrate explosives, and in particular to a method for evaluating the mixing effect and inspecting raw materials of on-site mixed granular ammonium nitrate explosives. Background Technology

[0002] On-site mixed porous granular ammonium nitrate explosive (AMF) is a granular explosive mixture composed of porous ammonium nitrate particles and fuel oil. It is primarily suitable for open-pit blasting projects and blasting operations without the risk of methane or mine dust explosions. The fuel oil mainly includes diesel, coal-derived oil, and engine oil. On-site mixing is typically carried out by an on-site mixing truck, which feeds porous ammonium nitrate particles and fuel oil into a mixing tank in specific proportions. After mixing at a set speed and for a specified time, the mixture is directly delivered into the blast hole. To ensure the quality of the explosive and the blasting effect, it is usually necessary to inspect the raw materials and conduct blasting tests on the mixed explosive sample at the blasting site or under similar or identical rock conditions before determining the mixing parameters to verify the explosive effect.

[0003] The most common existing method for quality inspection of porous granular ammonium nitrate is to test its oil absorption rate. This method involves mixing the porous granular ammonium nitrate with an oil phase material and then judging the oil absorption rate by observing the weight change. This method has the following significant drawbacks: First, the mixing time is relatively long, generally requiring about 10 minutes of manual mixing or stirring with simple tools, while in actual production, the mixing time is usually less than 30 seconds. Second, the volume ratio of porous granular ammonium nitrate to the oil phase material (such as diesel oil) during testing differs significantly from the actual production volume ratio. During testing, the porous granular ammonium nitrate is immersed in the oil phase material, with a volume ratio of approximately 1.5:1. In actual production, the oil phase material is sprayed onto the porous granular ammonium nitrate, resulting in a volume ratio of approximately 20:1. This difference in volume ratio cannot accurately reflect the actual production process, leading to distorted results. Based on experience, this test result can only prove infeasibility, not feasibility, and cannot guide production. Therefore, it is necessary to develop an evaluation method that can reliably reproduce the actual mixing effect, so as to use evaluation indicators to test the raw materials through laboratory reproduction.

[0004] It is generally believed that the more uniformly the oil phase material is dispersed in porous granular ammonium nitrate, the better the explosive performance. Therefore, by introducing a visual color difference, the degree of dispersion of the oil phase material in porous granular ammonium nitrate can be quantitatively expressed.

[0005] Current explosive sample preparation techniques lack evaluation indicators for assessing the mixing effect of explosives. Samples can only be prepared using on-site mixing equipment, resulting in multiple samples with different process parameters. Furthermore, the suitability of mixing parameters for the oil phase material is determined based on the explosion effect. If the oil phase material changes, samples must be prepared again and the blasting test repeated. Due to limitations in on-site equipment size, small batches of samples cannot be produced, leading to a large number of samples, significant waste, increased blasting operation costs, and increased blasting quality risks.

[0006] In actual production practice, the production process parameters of a certain mixing equipment (ammonium nitrate oil mixing truck), such as oil inlet rate, number of nozzles, nozzle position, and mixing time, are relatively fixed. This means the mixing capacity of the equipment is predetermined, and the uniformity of the mixture between porous granular ammonium nitrate and the oil phase material is fixed. If this mixing capacity is quantified using indicators, and then small-scale mixing equipment such as a kitchen mixer is used to prepare samples with the same mixing effect in small batches (generally less than 1 kg), the mixing capacity of this equipment can be quickly and reliably reproduced. This allows for the assessment of the compatibility or suitability of porous granular ammonium nitrate or the oil phase material, avoiding the blind use of new raw materials in production based on erroneous conclusions obtained from existing raw material testing methods, which could lead to losses or unnecessary safety risks. Based on this, this invention proposes a method for evaluating the mixing effect and inspecting raw materials of on-site mixed granular ammonium nitrate explosives. Summary of the Invention

[0007] The first objective of this invention is to address the lack of quantitative evaluation indicators for the mixing capacity of porous granular ammonium nitrate explosives (AMIG) in on-site mixing, which is a deficiency in existing technologies. This invention provides a method for evaluating the mixing effect of on-site mixed AMIG. This method involves adding a dye to the oil phase material, obtaining both dyed and undyed samples under on-site production conditions, and using the ratio of dyed to undyed samples as a quantitative indicator for evaluating the mixing effect. This allows for laboratory reproduction using the quantitative evaluation indicator, facilitating the judgment of the compatibility or suitability of raw materials using laboratory reproduction methods. This avoids losses or unnecessary safety risks caused by blindly using new raw materials in production based on existing methods. The second objective of this invention is to provide a raw material inspection method for on-site mixed porous granular AMIG. This method is used to determine the compatibility or suitability of porous granular ammonium nitrate or oil phase materials by using laboratory mixing reproduction methods and quantitative evaluation indicators, under conditions where the tested raw material is a variable factor or combined with changes in stirring parameters; or, to obtain the appropriate ratio of porous granular ammonium nitrate or oil phase materials when changing materials.

[0008] To achieve the primary objective, the present invention adopts the following technical solution.

[0009] A method for evaluating the mixing effect of porous granular ammonium nitrate explosives mixed on-site includes the following steps:

[0010] The first step is on-site sample collection: using on-site mixing equipment, an appropriate amount of dye is added to the oil phase material and mixed evenly. Under normal production conditions, the dyed oil phase material is mixed with porous granular ammonium nitrate. Under the condition that some of the porous granular ammonium nitrate is not dyed, the mixed explosive is randomly collected as on-site samples.

[0011] The second step is to evaluate the mixing effect: a set amount of the field sample is randomly selected, and the percentage of the number of stained and unstained porous granular ammonium nitrate in the field sample is obtained through statistical analysis and calculation. Either the stained and unstained ratio is defined as the evaluation index of the mixing effect of the mixed explosive.

[0012] The mixing effect evaluation method of the present invention, which adopts the aforementioned scheme, obtains on-site samples with dyed and undyed samples under on-site production conditions by adding a dye to the oil phase material. The ratio of dyed or undyed samples to the total samples is used as a quantitative index for evaluating mixing ability. This allows for laboratory reproduction using quantitative evaluation indicators, facilitating the judgment of the compatibility or qualification of new raw materials using laboratory reproduction methods. This avoids losses or unnecessary safety risks caused by blindly using new raw materials in production based on existing methods.

[0013] Preferably, in the first step, the ratio of the added dye to the oil phase material is by mass percentage, and the ratio is 0.01‰ to 2‰; the dye is composed of any one of Sudan Red, oil green, or oil emerald green. This allows for a variety of dyeing options while ensuring that the dyeing effect can be distinguished.

[0014] More preferably, the dye is Sudan Red; the proportion is 0.1‰ to 1‰. This achieves a more striking color differentiation effect, facilitating accurate differentiation and identification by visual recognition technology and improving the accuracy of the judgment results.

[0015] Preferably, in the second step, the statistical analysis of the number of stained and unstained porous granular ammonium nitrate includes counting by weight; or counting by particle number; or using image recognition technology to count the area of ​​an image within a designated region. This allows for the acquisition of basic data through multiple statistical methods, facilitating the selection or cross-referencing to verify the accuracy of the results.

[0016] To achieve the second objective, the present invention adopts the following technical solution.

[0017] A method for testing raw materials of porous granular ammonium nitrate explosives mixed on-site includes the following steps:

[0018] The first step is to collect data on the mixing effect on-site: Based on the evaluation method of the mixing effect of on-site mixing of porous granular ammonium nitrate explosives to achieve the first objective, the on-site mixing of porous granular ammonium nitrate explosives is evaluated, and quantitative evaluation indicators are obtained.

[0019] The second step is laboratory reproduction: using the same porous granular ammonium nitrate, dye, and oil phase material as in the production site, and mixing them thoroughly, a laboratory sample with the same mixing effect is obtained using an experimental mixer. The experimental conditions of the laboratory sample with the same mixing effect are recorded, and these experimental conditions are used as the experimental conditions for effect reproduction. The experimental conditions for effect reproduction include laboratory environmental conditions, data on mixed explosive raw materials, and mixing parameters.

[0020] The third step is the preparation of the test sample: one of the raw materials used to prepare the aforementioned mixed explosive is replaced with the material to be tested. In the laboratory, a mixing test is conducted using an experimental mixer according to the experimental conditions of the second step to obtain the test sample.

[0021] Step 4, Raw material qualification determination: Evaluate the mixing effect of the sample to be tested based on the evaluation indicators; when the mixing effect meets the evaluation indicator requirements, the raw material to be tested is determined to be qualified, and step 6 is executed; when the mixing effect does not meet the evaluation indicator requirements, the number of tests is determined; when the number of tests is less than the set value, step 5 is executed; when the number of tests is equal to the set value, the raw material to be tested is determined to be unqualified, and step 6 is executed.

[0022] Step 5, re-preparation of the test sample: Return to step 3 and change the stirring parameters of the experimental conditions for reproducing the effect; or, adjust the ratio of porous granular ammonium nitrate to oil phase material to re-prepare the test sample and obtain a new test sample.

[0023] Step 6: End the inspection.

[0024] The raw material inspection method of this invention, employing the aforementioned scheme, obtains a quantitative evaluation index of the mixing effect based on the on-site mixing effect evaluation method for porous granular ammonium nitrate explosives. Through laboratory mixing reproduction, and with the aid of the quantitative evaluation index, it achieves the judgment of the compatibility or qualification of porous granular ammonium nitrate or oil phase materials; or, to obtain the appropriate ratio of porous granular ammonium nitrate or oil phase materials when materials are changed. This method is mainly used for changes in the composition of the tested raw materials when the brand or manufacturer is changed; or, when the type of oil phase material is changed, requiring adjustment of mixing parameters. In the second step of laboratory reproduction, a correspondence should be established between the mixing parameters under laboratory conditions and the mixing parameters of the on-site mixing equipment, so that after raw material replacement, the mixing parameters of the on-site mixing equipment can be adjusted accordingly based on the laboratory mixing parameters corresponding to the new raw material. In practical applications, the number of repeated tests is usually no more than one or two, i.e., the set value for the number of tests is usually 2 or 3. Here, inspection refers to the process of obtaining the raw material qualification judgment result through the evaluation of mixing effect. That is, each test includes a complete process, which involves mixing the raw material to be tested as the only substitute material under laboratory reproduction conditions, based on the determined mixing effect evaluation index and the recorded laboratory reproduction conditions, and obtaining the material qualification judgment result through the mixing effect evaluation.

[0025] Preferably, the laboratory environmental conditions include temperature and humidity, in order to eliminate differences in test results caused by variations in environmental factors.

[0026] Preferably, the raw material parameters of the mixed explosive include the ratio of porous granular ammonium nitrate to oil phase material, the particle size of the porous granular ammonium nitrate, the type, viscosity, dye ratio, and proportion of oil phase material in the mixed explosive. This allows for the identification of influencing factors when the test results are unqualified, facilitating the implementation of corresponding measures.

[0027] Preferably, the stirring parameters include stirring speed, the proportion of stirring volume to the allowable stirring capacity, stirring duration, and the duration of oil phase material addition. By changing these parameters, the on-site mixing effect can be accurately reproduced, minimizing the differences between laboratory-prepared samples and on-site samples, thus achieving accurate reproduction of the on-site sample. Experiments show that a moderate stirring speed is ideal; excessively high or low speeds result in poor mixing. The proportion of stirring volume to the allowable stirring capacity mainly depends on the height of the agitator blades; the particle material on the test surface should be below the upper edge of the blades, as too close or below the upper edge leads to poor mixing. The duration of oil phase material addition refers to the interval from the start of addition to the complete addition. Experiments show that adding the oil phase material during the mixing process after the particle material is added to the mixer, and controlling the addition time, can ensure uniform mixing.

[0028] Preferably, the experimental mixer is a kitchen mixer that utilizes a plastic agitator head for mixing. The plastic agitator head has a symmetrical, grid-like blade structure, with the blades extending outwards in an arc from the mixing shaft. This design facilitates market procurement, reduces testing requirements, and leverages the advantages of small appliances with high energy consumption and low cost to lower testing costs. The plastic agitator head has no sharp edges and possesses good toughness, making it less likely to damage the granules. Even if a small breakage rate exists, it is within an acceptable range. Furthermore, the grid-like and arc-shaped outward-extending structure is beneficial to the integrity of the granules.

[0029] The beneficial effects of this invention are that the mixing effect evaluation method adds an appropriate proportion of dye to the oil phase material and uses the dyeing ratio of the mixed particles as a quantitative index for evaluating the mixing effect. This allows for laboratory reproduction using the quantitative evaluation index, facilitating the judgment of the compatibility or qualification of raw materials using laboratory reproduction methods. This avoids losses or unnecessary safety risks caused by blindly using new raw materials in production based on existing methods. It is used to determine the compatibility or qualification of porous granular ammonium nitrate or oil phase materials by using a laboratory mixing reproduction method and quantitative evaluation index, under conditions where the tested raw material is a changing factor or combined with changes in stirring parameters; or, to obtain the appropriate proportion of porous granular ammonium nitrate or oil phase materials when changing materials. Detailed Implementation

[0030] The present invention will be further described below, but this does not limit the invention to the scope of the embodiments described.

[0031] Example 1: A method for evaluating the mixing effect of on-site mixing of porous granular ammonium nitrate explosives, characterized by the following steps:

[0032] The first step is on-site sample collection: using on-site mixing equipment, an appropriate amount of dye is added to the oil phase material and mixed evenly. Under normal production conditions, the dyed oil phase material is mixed with porous granular ammonium nitrate. Under the condition that some of the porous granular ammonium nitrate is not dyed, the mixed explosive is randomly collected as on-site samples.

[0033] The second step is to evaluate the mixing effect: a set amount of the field sample is randomly selected, and the percentage of the number of stained and unstained porous granular ammonium nitrate in the field sample is obtained through statistical analysis and calculation. Either the stained and unstained ratio is defined as the evaluation index of the mixing effect of the mixed explosive.

[0034] In the first step, the ratio of the added dye to the oil phase material is expressed as a percentage by mass, and the ratio is 0.01‰ to 2‰; the dye is composed of any one of Sudan Red, oil green, or oil emerald green. Specifically, the dye is Sudan Red; the ratio is 0.1‰ to 1‰.

[0035] In the second step, the counting of the number of stained and unstained porous granular ammonium nitrate includes counting by weight; or counting by particle number; or counting by area of ​​the image within a set area using image recognition technology.

[0036] During the on-site sample collection process, 0.1‰ to 1‰ of Sudan Red was added to the oil tank of the on-site mixing vehicle, and then stirred by blowing air through a compressor to ensure that it was mixed evenly with the oil phase material.

[0037] The oil phase material is composed of diesel fuel.

[0038] Experiments show that using the ratio of undyed to total volume, also known as the whiteness rate, as an evaluation index, and through on-site collection and analysis of mixing equipment parameters, the mixing capacity of equipment with a whiteness rate of 14% under existing conditions was determined. When the whiteness rate of the mixed explosives is lower than or equal to 14%, the evaluation index requirement is met, meaning the mixing effect is good or qualified; when it is higher than 14%, the evaluation index requirement is not met, meaning the mixing effect is poor or unqualified.

[0039] Example 2, a method for testing raw materials for on-site mixed porous granular ammonium nitrate explosives, comprising the following steps:

[0040] The first step is to collect data on the mixing effect on-site: Based on the evaluation method for the mixing effect of porous granular ammonium nitrate explosives on-site in Example 1, the porous granular ammonium nitrate explosives mixed on-site are evaluated and quantitative evaluation indicators are obtained.

[0041] The second step is laboratory reproduction: using the same porous granular ammonium nitrate, dye, and oil phase material as in the production site, and mixing them thoroughly, a laboratory sample with the same mixing effect is obtained using an experimental mixer. The experimental conditions of the laboratory sample with the same mixing effect are recorded, and these experimental conditions are used as the experimental conditions for effect reproduction. The experimental conditions for effect reproduction include laboratory environmental conditions, data on mixed explosive raw materials, and mixing parameters.

[0042] The third step is the preparation of the test sample: one of the raw materials used to prepare the aforementioned mixed explosive is replaced with the material to be tested. In the laboratory, a mixing test is conducted using an experimental mixer according to the experimental conditions of the second step to obtain the test sample.

[0043] Step 4, Raw material qualification determination: Evaluate the mixing effect of the sample to be tested based on the evaluation indicators; when the mixing effect meets the evaluation indicator requirements, the raw material to be tested is determined to be qualified, and step 6 is executed; when the mixing effect does not meet the evaluation indicator requirements, the number of tests is determined; when the number of tests is less than the set value, step 5 is executed; when the number of tests is equal to the set value, the raw material to be tested is determined to be unqualified, and step 6 is executed.

[0044] Step 5, re-preparation of the test sample: Return to step 3 and change the stirring parameters of the experimental conditions for reproducing the effect; or, adjust the ratio of porous granular ammonium nitrate to oil phase material to re-prepare the test sample and obtain a new test sample.

[0045] Step 6: End the inspection.

[0046] Laboratory environmental conditions include temperature and humidity. Parameters for the mixed explosive raw materials include the ratio of porous granular ammonium nitrate to oil phase material, the particle size of the porous granular ammonium nitrate, the type, viscosity, and dye ratio of the oil phase material, and the proportion of the oil phase material in the mixed explosive. Stirring parameters include stirring speed, the proportion of stirring volume to the allowable stirring capacity, stirring duration, and the duration of oil phase material addition.

[0047] In practical applications, the number of repeated tests is usually no more than one or two, that is, the set value for the number of tests is usually 2 or 3.

[0048] The experimental mixer is composed of a kitchen mixer and uses a plastic agitator head for mixing; the plastic agitator head is a symmetrical blade structure with a grid-like structure, and the blades extend outward in an arc shape from the mixing shaft.

[0049] During the laboratory reproduction process, the kitchen mixer used was a BORAN FP3010 food mixer. To ensure uniform mixing, approximately 1000g of explosives were mixed at a time.

[0050] The experiment was conducted in a laboratory environment with a temperature of 15℃~20℃ and a humidity of 60%~70%, with a stirring speed of about 300 rpm. The stirring time of the granular material was about 30 seconds. During the stirring, the oil phase material that had been uniformly mixed with the dye was added. The addition time of the oil phase material was about 10 seconds. This method can reproduce the evaluation index of the mixing effect of on-site mixing, which is about 14% whiteness.

[0051] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A method for evaluating the mixing effect of a site-mixed porous granular ammonium nitrate fuel explosive, characterized in that, The method comprises the following steps: The first step is on-site sample collection: using on-site mixing equipment, a proper amount of dyeing agent is added to the oil phase material and mixed uniformly, and under normal production conditions, the dyed oil phase material is mixed with porous granular ammonium nitrate, and under the condition of ensuring that part of the porous granular ammonium nitrate is not dyed, the mixed explosive after mixing is randomly collected as the on-site sample; the ratio of the amount of the dyeing agent to the oil phase material is 0.01‰-0.5‰ by mass percentage; The second step is mixing effect evaluation: a certain amount of the on-site sample is randomly taken out, and through statistical analysis and calculation, the percentage ratio of the number of dyed and non-dyed porous granular ammonium nitrate in the taken sample is obtained, and either of the two ratios is defined as the mixing effect evaluation index of the mixed explosive; In the second step, the number of dyed and non-dyed porous granular ammonium nitrate includes statistics by weight, or statistics by particle number, or statistics by area in a set region using image recognition technology.

2. The mixing effect evaluation method according to claim 1, characterized by, The dyeing agent is composed of any one of Sudan red, oil green or oil turquoise green.

3. The mixing effect evaluation method according to claim 2, characterized by, The dyeing agent is Sudan red, and the ratio is 0.1‰-0.5‰.

4. A method for inspecting raw materials of a site-mixed porous granular ammonium nitrate fuel explosive, characterized by, The method comprises the following steps: The first step is on-site mixing effect collection: based on the mixing effect evaluation method of the on-site mixed porous granular ammonium oil explosive in any one of claims 1-3, the on-site mixed porous granular ammonium oil explosive is evaluated, and a quantitative evaluation index is obtained; The second step is laboratory reproduction: the same porous granular ammonium nitrate, the same dyeing agent and the same ratio of the mixed and uniform oil phase material as in the production site are used, and the same mixing effect laboratory sample is obtained by using an experimental mixer, and the experimental conditions of the laboratory sample with the same mixing effect are recorded, and the experimental conditions are used as the effect reproduction experimental conditions; the effect reproduction experimental conditions include laboratory environmental conditions, mixed explosive raw material data and stirring parameters; The third step is preparation of the sample to be tested: one of the raw materials for preparing the mixed explosive is replaced by the tested material, and the mixing test is carried out in the laboratory by using the experimental mixer according to the experimental conditions of the second step, and the sample to be tested is obtained; The fourth step is raw material qualification determination: the mixing effect of the sample to be tested is evaluated based on the evaluation index; when the mixing effect meets the requirements of the evaluation index, it is determined that the tested raw material is qualified, and the sixth step is performed; when the mixing effect does not meet the requirements of the evaluation index, the number of times of testing is determined, and when the number of times of testing is less than a set value, the fifth step is performed; when the number of times of testing is equal to the set value, it is determined that the tested raw material is unqualified, and the sixth step is performed; The fifth step is re-preparation of the sample to be tested: return to the third step, and change the stirring parameters of the effect reproduction experimental conditions; or adjust the ratio of the porous granular ammonium nitrate to the oil phase material to re-prepare the sample to be tested, and obtain a new sample to be tested; The sixth step is to end the test.

5. The raw material inspection method according to claim 4, characterized by, The laboratory environmental conditions include temperature and humidity.

6. The raw material inspection method according to claim 4, characterized by, The raw material parameters of the mixed explosive include the ratio of the porous granular ammonium nitrate and the oil phase material, the granularity of the porous granular ammonium nitrate, the variety of the oil phase material, the viscosity, the ratio of the dyeing agent, and the ratio of the oil phase material in the mixed explosive.

7. The raw material inspection method according to claim 4, characterized by, The stirring parameters include the stirring speed, the ratio of the stirring amount to the allowable stirring capacity, and the stirring duration, and the oil phase material adding duration.

8. The raw material inspection method according to claim 4, characterized by, The experimental stirrer is composed of a kitchen stirring mechanism and utilizes a plastic whipping blade head for stirring; the plastic whipping blade head is a symmetric blade structure of a fence type structure, and the blade extends outward in an arc line shape from the stirring shaft.