This standard specifies the determination method of the Hardgrove (abbreviated as Hardgrove) grindability index of coal. This standard is applicable to bituminous coal and anthracite. GB/T 2565-1998 Determination method of grindability index of coal (Hardgrove method) GB/T2565-1998 Standard download decompression password: www.bzxz.net

GB/T 2565--1998
This standard is revised based on the international standard ISO5074:1980 (E "Determination of the grindability index of hard coal-Hardgrove" and the Chinese standard GB/T25651987 "Determination of the grindability index of coal". It is equivalent to the international standard in terms of technology and content. According to the provisions of GB/T1.1--1993 and GB/T2565--1987 and the problems that have arisen in the implementation over the past 10 years. This standard retains the main technical contents of GB/T2565--1987 in the revision. Some clauses are supplemented and improved, and the preface of the country is added. Make the revised standard more perfect and in line with ISO. The first publication date of this standard is 1981. This standard shall replace GB/T2565-1987 from the date of its entry into force. Appendix A of this standard is the appendix to the standard.
Appendix B of this standard is the indicative appendix.
This standard is proposed by the State Administration of Coal Industry. This standard is under the jurisdiction of the National Coal Standardization Committee. The drafting unit of this standard: Beijing Coal Chemistry Research Institute of China Coal Research Institute. The main drafters of this standard: Chen Lizhu and Chen Huaizhen. This standard is entrusted to Beijing Coal Chemistry Research Institute of China Coal Research Institute for interpretation. 28
1 Fanquan
National Standard of the People's Republic of China
Determination of grindability index of coal(Hardgrove method)
Determination of grindability index of coal(Hardgrove method)
This standard specifies the method for determining the Hardgrove (abbreviated as Hardgrove) grindability index of coal. This standard is applicable to bituminous coal and anthracite.
2 Cited standards
GB/T2565-1998
Replaces GB/T2565-1987
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. The versions shown at the time of publication of this standard are valid. All standards will be revised. Parties using this standard should explore the possibility of using the latest versions of the following standards. GB474-1996 Preparation method of coal samples
GB/T6003-1985 Test sieve
3 Summary of methods||tt ||Grind coal samples of a certain size range and mass with the Hastelloy grindability tester and then screen them under specified conditions, and weigh the mass of the coal sample on the screen. The mass of the coal sample under the screen is obtained by subtracting the mass of the coal sample on the screen from the mass of the coal sample before grinding. The Hastelloy grindability index is then checked from the calibration chart drawn by the standard coal sample.
4 Instruments and equipment
4.1 Hastelloy grindability tester (referred to as Hastelloy tester): as shown in Figure 1. After the motor is reduced by a worm gear, a worm and a pair of gears, it drives the main shaft and the grinding ring to run at a speed of (20±1)r/min. The grinding ring drives the 8 steel balls in the grinding bowl to rotate. The diameter of the steel balls is 25.4mm. The total vertical force applied to the steel balls by the weight, gear, main shaft and grinding ring is (284±2)N. Approved by the State Administration of Quality and Technical Supervision on December 8, 1998 and implemented on May 1, 1999
GB/T 2565-1998
1—Machine base 2—Electric control box; 3—Worm gear box: 4—Motor; 5—Small gear; 6—Large gear: 7—Weight block; 8—Guard, 9—Lever; 10—Counter; 11—Spindle; 12—Grinding ring, 13—Steel ball, 14—Grinding bowl Figure 1 Hastelloy Grindability Tester
The grinding bowl is made of the same material as the grinding ring and has been quenched. Its geometric shape and size are shown in Figure 2. 498.43
R19.05±0.13
R19.05±0.13
$425.40±0.13
1 Spindle; 2—~ Grinding ring; 3—Grinding bowl + 4—Steel ball Figure 2 Grinding parts
The Hastelloy tester should be calibrated with a standard coal sample before being used for the determination of grindability index. 4.2 Test sieve (GB/T6003): The aperture is 0.071mm, 0.63mm, 1.25mm, the diameter is 200mm, and it is equipped with a sieve cover and a sieve bottom plate.
4.3 Protective sieve: A round hole sieve or square hole sieve that can be put on the test sieve, with an aperture range of 13 to 19mm. 4.4 Vibrating screen: It can accommodate a set of vertically stacked sieves with an outer diameter of 200mm and covered and sieve bottom plates. The vertical vibration frequency is 149min1, the horizontal rotation frequency is 221min~l, and the rotation radius is 12.5mm. 4.5 Balance: Maximum weighing 100g, sensitivity 0.01g30
GB/T2565—1998
4.6 Pan balance: Maximum weighing 1000g, sensitivity 1g. 4.7 Divider: In accordance with the provisions of GB474, the width of the sample grid is 5mm. 4.8 Crusher: Roller crusher, the spacing of the rollers is adjustable, and it can crush the coal sample with a particle size of 6mm to 1.25mm, and only produce the smallest coal powder less than 0.63mm.
5 Preparation of coal sample
5.1 According to the principles specified in GB474, crush the coal sample to 6mm. 5.2 Reduce the above coal sample to about 1kg, put it in a pan and spread it to a layer thickness of no more than 10mm, and weigh it after air drying (accurate to 1g). 5.3 Use a 1.25mm (4.2) sieve to sieve the above coal sample in batches, about 200g per batch, and use a step-by-step crushing method to continuously adjust the spacing of the rollers of the crusher (4.8) so that only larger particles can be crushed. Continue crushing and screening until all the above coal samples pass through the 1.25mm sieve. Keep the coal sample of 0.63~1.25mm and discard the sieved material. 5.4 Weigh the coal sample of 0.63~1.25mm on the pan (accurate to 1g), and calculate the percentage of the mass of the coal sample in this particle size range to the total mass of the coal sample before crushing (sample yield). If the sample yield is less than 45%, the coal sample is discarded. Reduce 1kg from the 6mm coal sample and prepare the sample again according to the sample preparation method in 5.3.
Note: When the amount of coal sample for geological exploration is small, if the sample rate after crushing is less than 45%, it can be measured, but the sample rate should be noted, and the result is for reference. 6 Measurement steps
6.1 Test run the Haarsberg instrument (4.1) to check whether it is normal, and then adjust the lever of the counter to the appropriate start position so that the instrument can automatically stop when running (60±0.25)r.
6.2 Thoroughly clean the grinding bowl, grinding ring and steel balls, and distribute the steel balls as evenly as possible in the groove of the grinding bowl. 6.3 Mix the coal samples of 0.63~1.25mm, separate 120g with a divider (4.7), and sieve with a 0.63mm sieve on a vibrating screen (4.4) for 5 minutes to remove coal powder less than 0.63mm; then use a divider to reduce it into two portions of coal samples, each of which is not less than 50g. 6.4 Weigh (50±0.01)g of coal sample from which coal powder has been removed and record it as m (g). Pour the coal sample evenly into the grinding bowl, level its surface, and sweep the coal sample that falls on the steel ball and the raised part of the grinding bowl to the area around the steel ball. Place the grinding ring in the grinding bowl when the cross groove of the grinding ring is basically in the same direction as the cross head at the lower end of the spindle.
6.5 Move the grinding bowl into the machine base, align the cross groove of the grinding ring with the cross head at the lower end of the spindle, and hang the grinding bowl on the bolts on both sides of the machine base, tighten and fix it to ensure that the total vertical force is evenly applied to the 8 steel balls. 6.6 Adjust the counter to zero, start the motor, and the instrument will automatically stop after running for (60±0.25)r. 6.7 Stack the protective screen (4.3), 0.071 mm sieve and sieve bottom plate, remove the grinding bowl, brush the coal powder stuck on the grinding ring onto the protective screen, then pour the ground coal sample together with the steel ball into the protective screen, and carefully brush the coal powder stuck on the grinding bowl and steel ball onto the protective screen. Then brush the coal powder stuck on the protective screen into the 0.071 mm sieve. Remove the protective screen and put the steel ball back into the grinding bowl. 6.8 Cover the sieve cover on the 0.071 mm sieve, put it on the vibrating screen together with the sieve bottom plate and vibrate for 10 minutes. Remove the sieve, brush the coal powder stuck under the 0.071 mm sieve surface into the sieve bottom plate, put it back on the vibrating screen and vibrate for 5 minutes, brush the bottom of the sieve surface once, vibrate for 5 minutes, and brush the bottom of the sieve surface again.
6.9 Weigh the coal sample on the 0.071mm sieve (accurate to 0.01g), recorded as ml (g). 6.10 Weigh the coal sample under the 0.071mm sieve (accurate to 0.01g). The sum of the masses of the coal samples on and under the sieve must not differ by more than 0.5g from the mass of the coal sample before grinding, m (g), otherwise the measurement result will be invalid and the test should be repeated. Note: If the sieve surface is loose, the sieve should be replaced.
7 Result processing
7.1 Calculate the mass mz (g) of the coal sample under the 0.071mm sieve according to formula (1). m2=mm
Where: m-bzxZ.net
mass of coal sample, 8;
m=--mass of material on the sieve.g,
m2—mass of undersize, g.
GB/T2565-1998
7.2According to the mass m2 (g) of the coal sample undersize, check the calibration chart (see Appendix A for the drawing of the calibration chart) to obtain the grindability index value (HGI). 7.3Take the arithmetic mean of two repeated measurements and round it off to an integer for reporting. 8 Precision
The precision of the grindability index determination is as specified in Table 1 Table 1
Repeatability
9 Instrument calibration
9.1The Hagrometer shall be calibrated with a grindability standard coal sample at least once a year. Reproducibility
9.2When the operator is replaced, the instrument or equipment (including the test sieve) is updated or repaired, or when the Hagrometer is suspected of having problems, the standard coal sample shall be used for calibration.
9.3The instrument calibration shall be carried out according to the method in Appendix A. 32
GB/T 2565—1998
Appendix A
(Appendix to the standard)
Drawing of calibration chart
A1 To draw the calibration chart, use a group of national grindability standard coal samples with grindability index standard values ​​of about 40.60, 80 and 110.4. Each standard coal sample is measured 4 times by the same operator using the unit's Haggard instrument according to the requirements and steps of Article 6 of the standard. Calculate the mass of the coal sample under the 0.071mm sieve and take its arithmetic mean. A2 On the rectangular coordinate paper, use the calculated average mass of the standard coal sample under the sieve as the ordinate and the standard value of its Haggard grindability index as the abscissa. According to the principle of least squares method, draw a graph for the measured data of the above 4 standard coal samples (see Figure A1). The straight line is the calibration graph of the Haggard instrument used.
Note: The least square method is to make a straight line that minimizes the sum of the squares of the distances from each measuring point on the graph along the axis to the straight line. Example: A unit uses a set of standard coal samples, and the data measured by the unit's Hardgrove instrument are shown in Table A1. Table Al
Hargrove grindability index
(standard value)
The calibration chart is drawn from this result:
The average value of the mass of the coal sample under the 0.071mm sieve calculated by four measurements g
Hargrove grindability index value
100110120
Calibration legend
GB/T2565-1998
Appendix B
(Standard Appendix)
Calibration of standard instruments and preparation of standard coal samples B1 The Hardgrove instrument imported from the United States is used as the standard weight for preparing the national standard drying sample of grindability index in my country. B2 The standard instrument must be calibrated with a set of 4 international standard coal samples obtained from the American Society for Testing and Materials (ASTM). B3 A set of 4 national standard coal samples for grindability are prepared by the Beijing Coal Chemistry Research Institute of the China Coal Research Institute and screened using dedicated standard instruments and standard test values.
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