GB/T 2007.7-1987 English PDF (GBT2007.7-1987)

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GB/T 2007.7-1987: General rules for the sampling and sample preparation of minerals in bulk. The method for determination of size by manual sieving
GB/T 2007.7-1987 (Renamed from GB 2007.7-1987)
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
UDC 622-3:543.05
GB/T 2007.7-87
Replacing GB 2007-1980
General Rules for the Sampling and Sample
Preparation of Minerals in Bulk - The Method for
Determination of Size by Manual Sieving
APPROVED ON: DECEMBER 15, 1987
IMPLEMENTED ON: OCTOBER 01, 1988
Approved by: National Bureau of Standards
Table of Contents
1 Applicable Scope ... 3
2 Normative References ... 3
3 Terms and Definitions ... 3
4 Instrument ... 4
5 Sieving Methods ... 4
6 Calculation of Results ... 5
7 Others ... 6
Additional Information: ... 7
General Rules for the Sampling and Sample
Preparation of Minerals in Bulk - The Method for
Determination of Size by Manual Sieving
1 Applicable Scope
This Standard is applicable to the determination of the grain-sizes of various minerals
specified in GB 2007.1.
2 Normative References
GB 2007.1 General Rules for the Sampling and Sample Preparation of Minerals
in Bulk-Sampling by Manual Method
GB 2007.2 General Rules for the Sampling and Sample Preparation of Minerals
in Bulk-Manual Method of Sample Preparation
GB 2007.5 General Rules for the Sampling and Sample Preparation of Minerals
in Bulk-Experimental Method for Checking the Bias of Sampling
GB 6003 Test Sieve
GB 6004 Square Mesh Woven by Metal Wire for Test Sieve
3 Terms and Definitions
3.1 Grain-size: it is expressed by the minimum mesh size that the substances pass
through the sieve in the sieving test.
3.2 Grain-size distribution: the sample is divided into the particle groups according to
the gran-size, which is expressed by the mass percentage.
3.3 Stacking density: the mass between the particles and inside the particle that is
included by the unit volume in the air, which is expressed by kg/m3.
3.4 Manual sieving: a sieving operation method, holding a sieve or a set of sieves by
hand to shake or vibrate for sieving. The remaining particles on the sieve were tested
in any direction by hand; and lightly placed on the sieve holes to try to pass or fail.
3.5 Sample-loading quantity: the mass of the sample loaded on the sieve in one sieving
operation.
3.6 Quantity of sample for sieving: the mass of minerals that is actually used in the
sieving test. All samples that are taken from a batch of minerals according to GB
2007.1.
4 Instrument
4.1 Sieve
4.1.1 Shape of mesh: square mesh.
4.1.2 Size of mesh: refer to GB 6003.
4.1.3 Shape and size of sieve frame: use a 200mm round sieve with a maximum grain-
size of 5.6mm and below. For minerals with a maximum grain-size greater than 5.6mm,
the shape and size of the sieve frame are not specified.
4.1.4 Preparation and verification of sieves: The sieves shall be carefully inspected
and cleaned before use. Both new sieves and sieves that have been used for a certain
period of time need to check the size of the meshes to ensure that the size of the mesh
is within the specified tolerance. For the check method, see GB 6003.
4.2 Weighing apparatus
The maximum weighing of the weighing apparatus is required to be close to the
quantity of sample used for sieving. If the conditions are not satisfied, it is allowed to
weigh for several times. The sensibility of the weighing apparatus used before sieving
is 0.5% of the maximum weighing; and the sensibility of other balances is 0.1% of the
maximum weighing.
4.3 Drying oven
It has the function of automatically controlling temperature.
5 Sieving Methods
5.1 Sample-loading quantity: according to the size of the mesh, the area of the screen
and the maximum grain-size of the sample, and maximum sample-loading quantity can
refer to Table 1.
5.2 Put the sample for sieving with less than the maximum sample-loading quantity
listed in Table 1 in the sieve of the specified aperture. Use multiple sieves of different