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GB/T 2007.2-1987 English PDF (GBT2007.2-1987)

GB/T 2007.2-1987 English PDF (GBT2007.2-1987)

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GB/T 2007.2-1987: [GB 2007.2-1987] General rules for the sampling and sample preparation of minerals in bulk. Sample preparation by manual method
GB 2007.2-1987
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
UDC 622-3:543.05
GB 2007.2-87
Replacing GB 2007-80
General rules for the sampling and sample
preparation of minerals in bulk
Sample preparation by manual method
APPROVED ON: DECEMBER 15, 1987
IMPLEMENTED ON: OCTOBER 1, 1988
National Standard Bureau
Table of Contents
1 Scope of application ... 3
2 Reference standards ... 3
3 Terms and definitions ... 4
4 Sample-preparation tools ... 4
5 General requirements for sample preparation ... 5
6 Crushing of the sample ... 6
7 Mixing of the sample ... 6
8 Reduction of the sample ... 6
9 Precision of sample preparation ... 10
10 Check of sample preparation system error ... 11
11 Sample preparation procedure example -- Riffle reduction method ... 12
12 Sample containers and labels ... 13
Annex A Mechanical mixers, reducers (Reference) ... 14
Additional information: ... 18
General rules for the sampling and sample
preparation of minerals in bulk
Sample preparation by manual method
1 Scope of application
This General Rules applies to the preparation of samples taken according to
the method specified in GB 2007.1.
The prepared sample shall be representative of the quality characteristics of
the original sample and suitable for analysis or test requirements.
This method describes the preparation of the following samples:
a. Moisture sample: particle size - 22.4 mm, 5 kg; - 10 mm, 2.5 kg.
b. Component analysis sample: maximum particle size 180 μm (80 mesh)
250 g;
c. Particle size sample: the sample is naturally air dried to make a particle
size sample.
2 Reference standards
GB 2007.1 General rules for the sampling and sample preparation of minerals
in bulk - Sampling by manual method
GB 2007.3 General rules for the sampling and sample preparation of minerals
in bulk - Experimental method for evaluation of quality variation
GB 2007.4 General rules for the sampling and sample preparation of minerals
in bulk - Experimental methods for checking the precision
GB 2007.5 General rules for the sampling and sample preparation of minerals
in bulk - Experimental method for checking the bias of sampling
GB 2007.6 General rules for the sampling and sample preparation of minerals
in bulk - Determination of moisture content - Heat drying method
GB 2007.7 General rules for the sampling and sample preparation of minerals
in bulk - The method for determination of size by manual sieving
I. Sample reduction sieve; 22.4 mm × 22.4 mm, 10 mm × 10 mm, 1 mm × 1
mm, 180 μm sieve.
5 General requirements for sample preparation
5.1 Sample preparation principle: The sample preparation is carried out in the
following three operation sequences (pre-drying if necessary).
Crushing: Reduce the particle size of the sample by crushing or grinding.
Mixing: Make the sample even.
Reduction: The sample is divided into two or more portions to reduce the mass
of the sample.
The above three operations are performed once to form a stage of sample
preparation. The stage of sample preparation shall select the sample amount
that reduces the sample preparation error without retaining too much sample,
and the sample preparation error is roughly inversely proportional to the sample
amount retained at each stage. In order to reduce the sample preparation error,
it is required to reduce the sample preparation stage. If the sample preparation
stage is increased, the sample preparation error will also increase accordingly,
unless the sample amount retained per stage is increased.
5.2 During the sample preparation process, the composition of the sample shall
be prevented from changing and contaminating. Moisture samples shall be
protected from moisture changes.
5.3 Pre-drying of sample: When the sample is too wet and too viscous to be
sieved, crushed and reduced, it can be dried at a temperature lower than the
temperature that may cause quality change (air drying or drying oven drying),
until the sample can pass freely through the crusher and reducer. Pre-drying
can be carried out at any stage of the sample preparation (see GB 2007.6-87
for the method for determining pre-drying moisture).
5.4 In case of large batch size, long loading and unloading time, rain, high
temperature and other conditions, the duplicate sample shall be made into the
moisture sample for measurement. If the sample cannot be prepared
immediately, the moisture sample shall be placed in a sealed container to
prevent changes.
5.5 The reduction and reuse of particle size samples, moisture samples, and
component analysis samples shall be specified in various standards for
sampling and sample preparation of ores.
6 Crushing of the sample
Mechanical equipment shall be used for the crushing of the sample. Manual
crushing is limited to crushing individual bulk samples into the maximum feed
size of the crusher at the first stage.
It shall select suitable crusher and grinder according to the hardness, particle
size of the ore and the use of the sample (for the crushing of the moisture
sample, it should not use non-sealed crushers that are easily generate heat or
have large air flow).
The performance of the crusher shall be checked regularly and adjusted to a
discharge particle size smaller than the specified particle size (checked with the
sample reduction sieve). In the process of preparing the component analysis
sample, the portion which is difficult to be crushed tends to have a difference in
component, so it is necessary to crush all the sample to the specified particle
size.
Use this batch of ore (no sample) to pass through the crusher before sample
preparation and then clean it. Samples remaining inside the crusher after
sample preparation must be taken out to prevent loss. In sample preparation,
the crusher shall be uniformly fed to avoid filling the crusher, so as to change
the running speed of the crusher and the particle size distribution of the
discharge.
7 Mixing of the sample
MIX the sample by any of the following methods:
7.1 Manual mixing
a. The sample is continuously passed through the riffle for three times, and
the two portions of sample are combined after each pass.
b. Small particle size samples (< 1 mm) can be mixed by hand three times.
7.2 Mechanical mixing
After the sample has been crushed to less than 10 mm, it can be mixed using
a double-cone mixer or a V-shaped mixer (see Annex A).
8 Reduction of the sample
The reduction of the sample can be either by mechanical or manual methods.
(The width of the opening of the hopper and
chute is more than three times the maximum particle size)
The riffle (see Figure 1) is a non-mechanical sample reducer. The sample is
divided into two equal portions. The adjacent grids discharge to the opposite
receiving container. The sample is usually fed by hand.
The width of the grid is at least 2.5 times the maximum particle size of the
sample, and half of the quantity of the grids is generally more than 8. The riffle
used shall be checked according to GB 2007.4 and GB 2007.5, and it can be
used only if it meets the requirements.
Reduction procedure:
a. The sample is mixed three times through the riffle and placed in a feed
container.
b. Flatten the sample in the feed container, and make the sample evenly
spread along the entire grid of the riffle when reducing. The feed rate shall
be controlled to ensure that the grid is not blocke...
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