Some standard content:
National Standard of the People's Republic of China
Method for sampling commercial coal
Sampling for cumimercial coal This standard adopts the international standard ISO1988-1975 "Hard coal - 1 Subject content and scope of application" equivalently.
GB 475-1996
Replaces GB175-83
This standard specifies the method for sampling commercial coal from coal flow, trains, cars, ships and coal. This standard applies to anthracite, bituminous coal and lignite. 2 Referenced standards
GB212 Industrial analysis method of coal
GB474 Preparation method of coal sample
GB477 Coal screening test method
3 Definition
3.1 Commercial coal sample
Replaces the coal sample with average properties of commercial coal.
3.2 Subsample
A sample taken as a result of a single operation of the sampling device or from a whole section of a coal flow. 3.3 Subsample
A coal sample consisting of several subsamples representing a part of the entire sampling unit. 3.4 Total sample
A coal sample formed by combining all the subsamples taken from a sampling unit. 3.5 Sampling unit
A quantity of coal represented by a total sample taken from a batch of coal, which may be one or more sampling units. 3.6 Batch
A separate quantity of coal for which overall properties are to be determined. 3.7 Nominal maximum particle size
The corresponding mesh size of the sieve with the cumulative mass percentage of the material on the sieve closest to (but not less than) 5%. 3.8 Sampling precision
The limit value of the difference (under 95% probability) between the single sampling measurement value and the mean value of the measurement value of countless samplings of the same coal (same source, same properties).
In the whole sampling, sample preparation and testing, the measurement result of a certain coal quality parameter will deviate from the true value of the parameter, but the true value cannot be obtained, that is, the degree of closeness between the measurement result and the true value - accuracy cannot be obtained, and only the degree of conformity between a series of measurement results of the same coal - precision can be estimated. If the sampling, sample preparation and testing methods used have only systematic deviations, precision is accuracy
Approved by the State Administration of Technical Supervision on June 14, 1996 and implemented on February 1, 1997
3.9 Systematic sampling
GB 475-1996
Sub-samples are taken at the same time, space or quality intervals, but the first sub-sample is randomly taken within the first interval, and the remaining sub-samples are taken at the selected intervals.
3.10 Random sampling
When taking sub-samples, no human will is imposed on the sampling location or time, so that materials in any location have the opportunity to be sampled. 3.11 Inch-based sampling
Sub-samples are taken at the same time intervals across the entire sampling unit. 3.12 Quality-based sampling
Sub-samples are taken at the same quality intervals across the entire sampling unit. 4 Sampling tools
4.1 Shovel
Used to sample from coal flow and stationary coal. The length and width of the shovel should be no less than 2.53 times the maximum particle size of the sampled coal. For coal with a maximum particle size greater than 150mm, a shovel with a length×width of about 300mm×250mm can be used. 4.2 Bucket
Used to intercept sub-samples at the falling coal flow. The opening size of the bucket should be at least 2.5~3 times the maximum particle size of the sampled coal. The capacity of the bucket should be able to accommodate all the coal in the entire cross-section of the coal flow when the conveyor is at full capacity. 4.3 Other machines for sampling stationary coal
Any manual or mechanical sampler that meets all of the following conditions can be used: 4.3.1 The opening size of the sampler is 2.5~3 times the maximum particle size of the sampled coal. 4.3.2 It can sample at the sampling points specified in this standard. 4.3.3 The amount of sub-samples taken meets the requirements of this standard, and there is no loss of coal samples during sampling. 4.3.4 The performance is reliable, and there is no failure that affects sampling and normal coal production and transportation. 4.3.5 The sampling has no systematic bias and the precision meets the requirements of the standard after being identified by the authoritative department. 5 Basic principles of sampling
5.7 Sampling unit
5.1.1 Clean coal and special industrial coal, according to the variety and user, are sampled in units of 1000 (100t, the same below), and other coals are sampled in units of 1000 according to the variety and user. 5.1.2 Imported and exported coal is sampled in units of delivery ratio or actual transportation volume per day according to variety and country. 5.1.3 When the transportation volume exceeds 1000t or is less than 10001, the actual transportation volume can be used as a sampling unit. If a single batch of coal quality verification is required, sampling, sample preparation and chemical analysis should be carried out on the same sample unit. 5.2 Sampling precision
The sampling precision of raw coal, screened coal, clean coal and other washed coal (including compromised coal) and other products is specified as follows. Table 1, sampling precision 1)
Cooled coal. Screened coal
Dry basis ash 20%
=1/1C× ash but not less than +1%
(percent value)
Ash content>20%
(absolute value)
Note: 1) In practical application, it is the total precision of sampling, sample preparation and testing. 5.3 Number of sub-samples (relative value) Other washed coal (including medium coal) (absolute value) GR 475--1996 5.3. 110001 The minimum number of sub-samples to be taken for raw coal, screened coal, clean coal and other washed coal (including medium coal) and lump coal with a particle size greater than 100 mm is specified in Table 2. Table 2 Minimum number of sub-samples 1 000 t Percent, % Raw coal, screened coal Deep sampling location Other washed coal (including smelted coal) and lump coal with a particle size greater than 100 mm Coal flow 5.3.2 Media volume exceeding 100! The number of sub-samples is calculated according to formula (1): N
Where: N
The actual number of sub-samples to be collected, pieces;
The number of sub-samples specified in Table 2, pieces;
-The actual number of coal waste sampled, 1
5.3.3 When the coal waste volume is less than 1000t, the number of samples shall be decreased in proportion to the number specified in Table 2, but shall not be less than the number specified in Table 3. The minimum number of sub-samples for coal waste less than 1000t is
+10% coal separation, coal decomposition, coal screening, sample selection, wet coal (including coal with particle size of 1000t) and particle size of 1000t. tum fast coal flow
table 2
1/3 of the number of days
5.4 Sub-sample mass
The minimum mass of each sub-sample is determined according to the nominal maximum particle size of commercial coal\according to the provisions of Table 4. Table 4 Sub-sample mass
Maximum particle size mm
Sub-sample mass.kg
Note:) The method of commercial coal nominal maximum particle size is shown in Appendix B. 6 Sampling in coal flow
1/2 of the number specified in Table 2
1/2 of the number specified in Table 2
6.1 Sampling of mobile coal flow t is carried out according to time-based sampling or mass-based sampling. The time or mass interval is calculated according to formula (2) or (3). The number and mass of sub-samples are determined according to the provisions of Articles 5.3 and 5.4 respectively. I:
· Sampling time interval m
Q-sampling unit, t:
G:--coal flow,/h:
a sub-sample number.
Where: m—sample quality interval, 1:
-beam sample unit, :
a sample number.
GB 475-1996
6.2 When sampling at the falling point of the moving coal flow, according to the flow of the coal and the width of the belt, a sub-sample can be collected by using a bucket or shovel to intercept the entire coal flow once or 2 to 3 times. When intercepting 2 to 3 times, it shall be carried out in the order of left and right or in the middle. The sampling parts shall not be staggered. When sampling, the shovel can only pass through the coal flow once, that is, it can only be sampled when entering or withdrawing from the coal flow, and it cannot be accompanied by entering and exiting. 6.3 When the coal sample is taken by shoveling on the moving coal stream, the moving speed of the belt should not be too high (generally not more than 1.5 m/s), and safety should be ensured. 7 Sampling on the top of the train
7.1 The number of sub-samples and the quality of the samples shall be determined in accordance with the provisions of Articles 5.3 and 5.4. However, at least 3 sub-samples shall be taken from each car of raw coal and screened coal regardless of the size of the slab capacity; at least 1 sub-sample shall be taken from each car of clean coal, other washed coal and lump coal with a particle size greater than 100 mm. 7.2 Sub-point layout
7.2.1 Diagonal 3-point layout: As shown in Figure 1, 3 samples are arranged on the diagonal line of the car body. Samples 1 and 3 are 1m away from the car corner, and the second sample is located in the middle of the diagonal line.
7.2.2 Linear 5-point layout: As shown in Figure 2, 5 sub-samples are arranged on the diagonal line of the car body. Samples 1 and 5 are 1m away from the car corner, and the remaining 3 sub-samples are equally divided into samples 1 and 5.
7.2.3. For raw coal and screened coal, three sub-samples shall be taken from each car as shown in Figure 1; for clean coal, other washed coal and lump coal with a particle size greater than 100 nm, one sub-sample shall be taken from each car as shown in Figure 2. 7.2.4 When less than 6 car wagons are used as sampling units, the sampling points shall be distributed according to the principle of "evenly distributing points so that each part of the coal has a chance to be sampled". In addition, when the number of sub-samples per car wagon exceeds 3 (for raw coal and screened coal) or 5 (for clean coal and other washed coal), the excess samples can be distributed on the intersecting lines or on the car wagon bisectors shown in Figure 3. When raw coal and screened coal are sampled with 1 car wagon as the sampling unit, the 18 sub-samples can be distributed on both intersecting lines. The diagonal line of the train can also be distributed in the 18 blocks shown in Figure 4. Figure 3
7.3 When sampling the top of the train, the mine (or coal washing plant) should take the sample immediately after loading. In Guangchuan, the pit should be dug to 0.4m below. Before sampling, the coal blocks and grinding stones that have rolled down to the bottom of the pit should be cleaned up. 7.4 Raw coal, according to GB477, if the content of coal blocks with a particle size of more than 150mm (including grinding stones) exceeds 5%, when sampling the most commercial coal, those larger than 150mm will no longer be taken in, but the ash content or heat star of the batch of coal should be calculated according to formula (4): Xa= XP-Xa(100-- P)
Where: X. Actual ash content or calorific value of coal at the commercial station, % or MJ/kg; Xan2 ash content or calorific value of coal with a particle size greater than 150mm, % or M1/kg; Xa—ash content or calorific value when coal with a particle size greater than 150mm is not mined, % or MJ/kgP——Percentage of coal with a particle size greater than 150mm, Le. 8 Sampling on the car
8.1 Number and quality of sub-samples 8.2 Distribution of sub-sample points:
Regardless of raw coal, screened coal, clean coal, other washed coal or coal with a particle size greater than 150mm, sub-samples shall be collected in a circular manner at 3 points (the last two points are .5m away from the corner of the car) along the diagonal of the car. When more than one sub-sample is required on a car, the sample shall be distributed on the diagonal or bisector or the entire surface of the car according to the principles described in 7.2.4. The remaining requirements of 8.3 are the same as those of 7.3 and 7.4. 9 Sampling on board
9.1 On board: Do not directly take the arbitration coal sample and the incoming and outgoing coal sample, and generally do not directly take other commercial coal samples, but should take samples in the coal medium flow of the belt conveyor or other loading (unloading) tools, such as cars, during the coal loading (unloading) process. 9.2 Sampling directly on board, generally take "tank" of coal as the sampling unit, and can also divide the coal in one warehouse into several sampling units. 9.3 The number of samples and the quality of samples shall be in accordance with Articles 5.3 and 5.4. 5.4. 9.4 Arrangement of sub-sample points:
According to the principle described in Article 7.2.1, the ship's hold is divided into 2-3 layers (one layer every 3~4m), and the samples are evenly distributed on the surface of each layer. Figure 5 is an example of stratification for sampling in 3 layers.
1-Approximate cargo volume
2-Approximate unloading→
3-Major unloading sound
10. Pile sampling
GB 475—1996
Equal separation level
Upper level
Half depth water
Lower level
10.1 Coal pile. F. No arbitration coal sample and export coal sample are taken. If necessary, the coal pile should be transferred and the sampling method during the transfer process should be used for sampling. 10.2 The number and quality of sub-samples should be determined in accordance with Articles 5.3 and 5.4. 10.3 Arrangement of sub-sample points:
According to the principle described in Article 7.2.1, according to the shape of the coal pile and the number of sub-samples, the sub-samples shall be distributed at the top, waist and bottom (0.5 m from the ground) of the coal pile. When sampling, 0.2% of the surface layer shall be removed first. 11 Collection of total moisture coal samples
11.1 The total moisture coal sample can be collected individually or separately during the coal sample preparation process. 11.2 Individual sampling:
11.2.1 Sampling in the coal flow: according to the time-based or mass-based sampling method. The number of sub-samples shall be at least 10 for every 1,000 tons regardless of the variety. When the coal is larger than 100 tons, it shall be calculated according to formula (1); when the coal quantity is less than 1,000 tons, at least 6. The sample quantity shall be determined according to the provisions of Article 5.4. 11.2.2 Samples collected on trains: After loading, samples are collected along the diagonal of the car body by the 5-point cycle method (see Figure 2). Regardless of the type, at least one sub-sample is collected from each car; when the coal is less than 1,000 tons, at least 6 sub-samples are collected. The quality of the sub-samples shall be determined in accordance with the provisions of Article 5.1. 11.2.3 Samples collected on cars: After loading, samples are collected along the diagonal of the car body by the 3-point cycle method. When the coal volume is less than 1,000 tons, at least 6 sub-samples are collected. The quality of the sub-samples shall be determined in accordance with the provisions of Article 5.4. 11.2.4 The total moisture content of coal samples shall not be collected separately from coal piles and ships. 11.2.5--A batch of coal can be collected several times to form several sub-samples. The number of sub-samples for each sub-sample is determined by referring to the above, and the weighted average of the total moisture content of each sub-sample is taken as the per ton moisture value of the batch of coal. 11.3 Sampling during coal sample preparation:
11.3.1 The sampling of total moisture coal samples shall be carried out in accordance with G13474. 11.3.2 If the coal samples of a batch of coal are divided into several sub-samples, the total moisture coal samples shall be taken during the preparation of each sub-sample, and the weighted average of the total moisture of each sub-sample shall be taken as the total moisture value of the batch of coal. 11.4 After the moisture coal samples (whether total samples or sub-samples) are taken, they shall be prepared and tested immediately, otherwise, they shall be immediately placed in a sealed container, the coal sample mass shall be marked, and the samples shall be prepared and tested as soon as possible.
GB 475 1996
Verification of sampling precision
(Supplement)
A1 For 1000t coal, the coal can be sampled at the top of the coal flow or at the coal mine 1 in the form of 6 sub-samples. The number of samples for each sub-sample is 1/6 of the number of samples specified in Table 2. When the number of sub-samples to be collected cannot be divided by 6, the number of sub-samples should be appropriately increased (not reduced) to make it a multiple of 6. The sub-samples should be placed in 6 containers alternately. Taking the raw coal with ash content greater than 20% as an example, the number of samples specified in Table 2 is 60 tt| ... If the range is between 4.91 and -2.4 (in this case, between 9.8 and -2.4), it is considered that the sampling precision specified in Table 1 has been achieved according to the number of sub-samples specified in Table 2. If the range is greater than 4.9A (in this case, 9.8), it means that the specified sampling precision cannot be achieved when sampling according to the specified number of sub-samples. In this case, the number of sub-samples should be increased (usually 50 times the specified number first), and then the above method should be used for verification. If the difference (range) between the maximum and minimum values of the ten sub-samples is between 4.91 and 1.24 If the range is less than 1.2A (2.4 in this case), the number of sub-samples can be reduced by 33% and the above method can be used to check again to determine the number of sub-samples that meet the sampling precision. A2 should be checked at least once every six months: Generally, two or three tests are carried out in a row (two weeks and three weeks in reverse order). If two consecutive tests meet the requirements (or do not meet the requirements) or two of the two tests meet the requirements, the sample should be checked once every six months. The requirement (or not meeting the requirement) indicates that the sampling in the half year has met (or not met) the specified precision requirement.
Appendix B
Screening test to determine the mass of the original coal sub-sample and the ratio of coal blocks larger than 150mm (supplement)
B1 Take the sieved coal sample for the two top tests on the top of the train wagon according to GB477. B2 For 1000t of coal, regardless of the capacity of the wagon, take a sample of not less than 30kg from each wagon 1 along the diagonal direction and at 5 points as shown in Figure 2 of this standard. B3 Combine the sub-samples into sieved coal and weigh them (about 6010 kg) to an accuracy of 0.5 kg. B4 Pass through the round or square hole sieves of 150.100, 50, and 25mm, and weigh the mass of the sieve to an accuracy of 0.5kg calculate the percentage of the oversize in the whole coal sample mass, and obtain the ratio of coal pieces larger than 150mm. B5 The sieve hole size with the closest cumulative rate of oversize but not larger than 5 is taken as the maximum particle size of the raw coal, and the quality of the sub-coal is calculated from Table 3 accordingly.
B6 At least one test shall be conducted every half an hour, and the test results shall represent the maximum particle size of the raw coal and the ratio of coal pieces larger than 150mm within half a year (or shorter time). bzxZ.net
GB4751996
Additional Notes:
This standard is proposed by the Ministry of Coal Industry of the People's Republic of China. This standard is under the jurisdiction of the National Coal Standardization Technical Committee. This standard was drafted and interpreted by the Beijing Coal Chemistry Research Institute of the China Coal Research Institute. The main drafters of this standard are Bao Shiqi, Duan Yunlong and Meng Xianying. This standard was first issued in January 1964.
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