This standard specifies the definition, tools, basic principles, sampling methods and sampling precision of industrial coal briquette samples. This standard is applicable to various industrial coal briquette samples. MT/T 915-2002 Industrial coal briquette sample sampling method MT/T915-2002 standard download decompression password: www.bzxz.net

ICS73.040
Registration number: 113242002
Coal Industry Standard of the People's Republic of China
MT/T915---2002
Sampling for industrial briquette
Sampling for industrial briquette2002-04-08 Issued
National Economic and Trade Commission
2002-09-01 Implementation
MT/T915-2002
This standard is formulated after a large number of tests based on the characteristics of industrial briquette with reference to GB475-1996 "Method for Sampling Commercial Coal" and a large number of tests.
The Appendix^ of this standard is a normative appendix.
This standard is proposed by the China Coal Industry Association. This standard is approved by the State Economic and Trade Commission.
This standard is under the jurisdiction of the National Coal Standardization Technical Committee. This standard was drafted by: Coal Analysis Laboratory of China Coal Research Institute, Coal Shape Design Institute of Beijing Campus of China University of Mining and Technology. The main drafters of this standard are: Fang Quanguo, Xiao Naiyou, Huang Zhongcheng. This standard is formulated for the first time.
1 Scope
Coal Industry Standard of the People's Republic of China
Methods for Sampling Industrial Briquettes
Sampling for industrial briquetteMT/T 915—2002
This standard specifies the definition, tools, basic principles, sampling methods and sampling precision for sampling industrial briquette. This standard applies to various industrial briquettes.
2 Normative References
The clauses in the following documents become the clauses of this standard through reference in this standard. For any dated referenced document, all subsequent amendments (excluding errata) or revisions are not applicable to this standard. However, the parties to the agreement based on this standard are encouraged to study whether the latest versions of these documents can be used. For any undated referenced document, the latest version shall apply to this standard. GB212 Industrial analysis methods of coal
GB474—1996 Preparation methods of coal samples
3 Terms and definitions
This standard uses the following terms and definitions.
3.1 Industrial briquette industrialbriquette Coal products with certain shapes, sizes and strengths processed from various coals are called briquette. Briquettes used as industrial fuels, industrial raw materials and other industrial purposes are called industrial briquette.
3.2 Briquette sample sample
A sample representing the average properties of briquette.
3.3 Nominal size normal size
The nominal size of briquette products.
3.4 ​​Increment
A portion of sample taken when the sampling device is operated once or when the entire section of the briquette flow is cut off once. 3.5 Gross sample
A briquette sample formed by combining all the sub-samples taken from a sampling unit. 3.6 Sampling unit unit for sampling The amount of briquette represented by a total sample taken from a batch of briquette. A batch of briquette can be one or more sampling units. 3.7 Batch 1ot The amount of an independent briquette that needs to be measured for overall properties. 3.8 Precision for sampling The limit value of the difference (under 95% probability) between the single sampling measurement value and the average value of the measurement value of countless samplings of the same briquette (same source, same properties). In the whole sampling, sample preparation and measurement, the measurement result of a certain parameter will deviate from the true value of the parameter, but the true value cannot be accurately obtained, that is, the degree of closeness between the measurement result and the true value - accuracy - cannot be obtained, but only the degree of compliance between a series of measurement results of the same briquette - precision can be estimated. If the sampling, sample preparation and determination methods used are free of systematic errors, precision is accuracy. 3.9 Systematic sampling systematic sampling takes sub-samples at the same time, space or mass interval, but the first sub-sample is randomly taken within the first interval, and the remaining sub-samples are taken at selected intervals.
3.10 Random sampling random sampling
When taking sub-samples, no artificial will is imposed on the sampling location or time, so that materials in any location have the opportunity to be sampled. 3.11 Time-base sampling time-base sampling takes sub-samples at the same time intervals through the entire sampling unit. 3.12 Weight-base sampling weight-base sampling takes sub-samples at the same mass intervals through the entire sampling unit. 4 Sampling tools
4.1 Sampling shovel
Used for sampling in the flow of briquette and in stationary briquette. The length and width of the shovel should not be less than 3 times the nominal particle size of the briquette to be sampled. For briquette with a nominal particle size greater than 100mm, a shovel with a length × width of about 300mm × 250mm can be used. 4.2 The receiving bucket
is used to intercept sub-samples at the falling part of the briquette flow. The opening size of the bucket should be at least 3 times the nominal particle size of the sampled briquette. The capacity of the receiving bucket should be able to accommodate all the briquette volume of the entire cross-section of the briquette flow when the conveyor is at its maximum capacity. 5 Basic principles of sampling
5.1 Sampling unit
5.7.1 A batch of 200t is a basic sampling unit. 5.1.2 When the daily production volume, actual shipment volume or yard storage volume is greater than or less than 200t, the actual batch is a sampling unit. 5.2 Sampling precision
This standard uses dry ash content and compressive strength to express sampling precision. The precision regulations are shown in Table 1. When the sampling purpose is to determine the chemical properties of briquette, the dry ash precision is used. When the sampling purpose is to conduct strength tests, the compressive strength precision is used. Table 1 Sampling precision
About basic ash content/%
±1.00 (absolute)
5.3 Number of sub-samples
5.3.1 The number of sub-samples for each basic sampling unit is 10. 5.3.2 When the batch is less than 200t, the number of sub-samples is 10. 5.3.3 The number of sub-samples N (pieces) for a batch larger than 200t shall be calculated according to formula (1): m
N= n200
Where: m—the actual batch of briquette sampled, t; the number of sub-samples for a basic sampling unit, pieces. 5.4 Sub-sample mass
Compressive strength/(N·piece-1)
S20% (relative)
(1)
For nominal particle size less than or equal to 50mm, the sub-sample mass shall not be less than 2kg; for nominal particle size greater than 50mm, the sub-sample mass shall not be less than 4kg. 2
6 Sampling method
6.1 Sampling in the flow of shaped coal
MT/T 915--2002
6.1.1 Sampling in the flow of moving shaped coal is carried out by time-based sampling or mass-based sampling. The time interval T (min) is calculated according to formula (2), and the mass interval m (t) is calculated according to formula (3).
Where: Q——sampling unit, t;
G——flow rate of shaped coal, t/h;
Number of sub-samples.
（2）
（3）
6.1.2 When sampling at the falling point of the moving shaped coal flow, according to the flow rate of shaped coal and the width of the belt, use a bucket or shovel to cross-section the entire cross-section of the shaped coal flow once or twice or three times to take a sub-sample. When intercepting twice or three times, it shall be carried out in the order of left and right or left, middle and right, and the sampling positions shall not be staggered and repeated. When sampling with a sampling shovel, the sampling shovel can only pass through the briquette flow once, that is, it can only take samples when entering or withdrawing from the briquette flow, and cannot take samples when entering or exiting.
6.1.3 When sampling on the moving briquette flow belt, the sampler must be close to the belt, and it is not allowed to shovel the briquette flow in the air. The sampler can only intercept once on the belt for each sub-sample.
6.2 Sampling on the top of the train
6.2.1 Arrangement of sub-sample points: As shown in Figure 1, 3 sub-sample points are arranged along the diagonal of the car body for each car. The 1st and 3rd sub-samples are 1m away from the car corner, and the second sub-sample is located in the center of the diagonal.
6.2.2 When the batch is greater than 200t, the number of sub-samples N (pieces/section) taken by each car is calculated according to formula (4) and rounded to an integer (decimals are rounded up and not rounded up) and the sub-samples are distributed cyclically at 3 points.
Where: N——Number of sub-samples calculated according to formula (1), N2—Number of vehicles, knots.
·（4）
6.2.3 When the batch is less than 200t (small number of wagons), 10 sub-sample points shall be evenly distributed on the cross diagonal lines of each wagon according to the principle of "evenly distributing points so that every part of the briquette has a chance to be mined". When there is only one wagon, the 10 sub-samples shall be distributed in the 10 blocks shown in Figure 2.
6.3 Sampling on cars
Along the diagonal direction of the car, take one sub-sample from each car in a 3-point cycle (the first and last points are 0.5m away from the car corner). The first sub-sample shall be taken by 3
MT/T 915—2002
machine. When more than one sub-sample is required on a car, the sub-samples shall be distributed on the diagonal or the entire car surface according to the principle described in 6.2.3.
Sampling of shaped coal pile
According to the principles stated in Article 6.2.3, the sub-samples shall be distributed on the top, waist and bottom (0.5 m from the ground) of the coal pile according to the shape of the coal pile and the number of sub-samples.
MT/T 915-2002
Appendix A
(Normative Appendix)
Verification of sampling precision
A1 For 200t or more of shaped coal, sampling can be carried out in the form of 6 sub-samples at the top of the shaped coal flow and transportation vehicle. The number of sub-samples for each sub-sample is 1/6 of that specified in Article 5.3. When the number of sub-samples to be collected cannot be divided by 6, the number of sub-samples shall be appropriately increased (not reduced) to make it a multiple of 6. Each sub-sample shall be placed in 6 containers in an alternating manner. Taking the briquette with ash content less than 20% as an example, the number of sub-samples is 10+2=12 (2 times of 6) according to this regulation, then
No. 1 and No. 7 sub-samples are collected in the first sub-sample; No. 2 and No. 8 sub-samples are collected in the second sub-sample; bzxZ.net
No. 3 and No. 9 sub-samples are collected in the third sub-sample, No. 4 and No. 10 sub-samples are collected in the fourth sub-sample; No. 5 and No. 11 sub-samples are collected in the fifth sub-sample; No. 6 and No. 12 sub-samples are collected in the sixth sub-sample. These 6 sub-samples should be prepared separately and the moisture and ash content should be determined according to the provisions of GB474 and GB212. The average of the repeated determination results is taken as the reported result. If the difference (range) between the maximum and minimum values ​​of the dry ash content among the six sub-samples is between 4.9 and 1.2 (the sampling precision expressed in dry ash content specified in Table 1 is ±1.00%), it is considered that the number of sub-samples specified in Article 5.3 has reached the sampling precision specified in Table 1; if the range is greater than 4.9, it means that the sampling precision specified in Table 1 cannot be achieved when sampling according to the number of sub-samples in Article 5.3, and the number of sub-samples will be increased by 50% for the next sampling; if the range is less than 1.2, the number of sub-samples will be reduced by 33% for the next sampling, and the above method will be used for re-checking. A2 should be checked at least once a year. Generally, two or three consecutive tests (carried out in two to three weeks) are required. If the results of two consecutive checks meet the requirements (or do not meet the requirements) or two of the three checks meet the requirements (or do not meet the requirements), it means that the sampling in that year meets (or does not meet) the specified precision requirements.
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