GB/T 10322.7-2016 English PDF (GBT10322.7-2016)

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GB/T 10322.7-2016: Iron ores and direct reduced iron -- Determination of size distribution by sieving
GB/T 10322.7-2016
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 73.060.10
D 31
GB/T 10322.7-2016 / ISO 4701:2008
Replacing GB/T 10322.7-2004
Iron ores and direct reduced iron - Determination of
size distribution by sieving
(ISO 4701:2008, IDT)
ISSUED ON: DECEMBER 30, 2016
IMPLEMENTED ON: SEPTEMBER 01, 2017
Issued by: General Administration of Quality Supervision, Inspection and
Quarantine of the PRC;
Standardization Administration of the PRC.
Table of Contents
Foreword ... 3 
1 Scope ... 9 
2 Normative references ... 9 
3 Terms and definitions ... 10 
4 Principles and planning ... 10 
5 Apparatus ... 17 
6 Samples ... 20 
7 Procedures ... 21 
8 Verification ... 30 
9 Results ... 30 
10 Test report and working log ... 33 
11 Precision ... 33 
Annex A (Informative) Steps for establishing the operating conditions for the
determination of size distribution using a single sieve or a nest of sieves ... 35 
Annex B (Normative) Scheme of sample preparation and sieving procedure 36 
Annex C (Normative) Maximum mass to be retained on a sieve at completion
of batch sieving (m) in order to obtain good sieving efficiency ... 37 
Annex D (Informative) Size apertures in R20 and R40/3 series ... 38 
Annex E (Informative) Typical batch sieving apparatus ... 39 
Annex F (Informative) Desirable features of mechanical sieving machines ... 40 
Annex G (Normative) Procedure for determining the minimum mass of sample
used for sieving ... 44 
Annex H (Normative) Flowsheet of the procedure for the acceptance of
analytical values for test portions ... 48 
Annex I (Informative) Explanation ... 49 
Annex J (Normative) Determination of the average particle size (APS) ... 51 
Foreword
GB/T 10322 "Iron ores" is divided into 8 parts:
- Part 1: Iron ores - Sampling and sample preparation procedures;
- Part 2: Iron ores - Experimental methods for evaluation of quality variation;
- Part 3: Iron ores - Experimental methods for checking the precision of
sampling;
- Part 4: Iron ores - Experimental methods for checking the bias of sampling;
- Part 5: Iron ores - Determination of the moisture content of a lot;
- Part 6: Iron ore - Determination of decrepitation index;
- Part 7: Iron ores and direct reduced iron - Determination of size distribution
by sieving;
- Part 8: Iron ores - Single-point determination of specific surface area -
Nitrogen adsorption method.
This Part is Part 7 of GB/T 10322.
This Part is drafted in accordance with the rules given in GB/T 1.1-2009.
This Part replaces GB/T 10322.7-2004 "Iron ore - Determination of size
distribution by sieving". Compared with GB/T 10322.7-2004, in addition to
editorial changes, the main technical changes of this Part are as follows:
- Add direct reduced iron to the scope of application; so change the standard
name to "Iron ores and direct reduced iron - Determination of size
distribution by sieving".
- In Clause 1 Scope, change the previous "This Standard specifies the
methods to be employed for determination of size distributions by sieving
of iron ore, utilizing sieves having aperture sizes of 36 μm or larger. The
size distribution is expressed in terms of mass and percentage mass,
passed or retained on selected sieves. The purpose of this Standard is to
provide a basis for any testing of iron ore involving size determination for
use by contracting parties in the sale and purchase of these materials" TO
"This Part of GB/T 10322 specifies the methods to be employed for
determination of size distributions of iron ore and direct reduced iron. This
Part applies to the determination of size distributions of iron ore and direct
reduced iron, utilizing sieves having aperture sizes of 36 μm or larger".
- Change the previous Clause 4"Principles and scheme" to "Principles and
planning".
- Supplement the ground state requirements for test samples that "The
determination of size distribution of iron ores and direct reduced iron (DRI)
may be carried out on a ‘dry’ or ‘natural’ (or ‘as-received’) basis" to the 4.1
“General”.
- Simplify the content of 4.3.1 Effect of moisture content; change to "When it
is difficult to conduct sample division due to sample being adhesive or
excessively wet, the sample shall be dried to constant mass in accordance
with 7.1".
- In 4.3.2, change "For brittle iron ore during particle size analysis, the
deviation check between mechanical sieving and hand sieving shall be
carried out according to the procedure given in GB/T 10322.4-2000 (see
5.2)" TO "There are differences in degradation of ores. Certain iron ores,
particularly lump ore, and DRI may be subject to significant degradation
during the sampling and size analysis sequences. Furthermore, different
sampling and size analysis processes can cause degradation of ores and
DRI to different extents. Consequently this may lead to significant variation
in results for the same lot. It is therefore essential that any degradation
should be minimized through the correct design of manual sampling,
mechanical sampling and size analysis systems. Sampling systems should
be designed in accordance with the guidelines set out in ISO 3082 and ISO
10835".
- In subclause 4.3.3, change "For iron ores with pronounced magnetic
properties, demagnetization of the size sample shall be carried out" TO "For
iron ores with pronounced magnetic properties and DRI that has been
handled by magnets, it is desirable to ensure that the size sample be
demagnetized or that the sieves are non-magnetic".
- In subclause 4.4, change "Sampling methods for iron ore (GB/T 10322.1)
will generally provide number of samples in excess of the sieving
requirements" TO "Iron ore and DRI are prepared according to ISO 3082
and ISO 10835 for the number of samples required for sieving, respectively".
- Change the previous 4.5 "Choice of dry and wet sieving" to "Choice of
sieving method".
- Change the content in subclause 4.5.1 to "Two different sieving methods
are available to perform particle size analysis (see Annex I): a) dry sieving,
i.e. sieving without the application of water; b) wet sieving, i.e. sieving with
a sufficient application of water to ensure the passage of undersize particles
through the sieve apertures. A table summarizing the sample preparation
and sieving procedure is given in Annex B".
- In subclause 4.5.2, change "The choice of sieving method for each part of
a size determination shall be made on the basis of attaining the defined
precision of testing (see 11.1). Details on the procedure shall be recorded
in the working log" TO "The results of these methods may not be the same.
No specific preference is given in this Part for either method when sieving
iron ore samples. For DRI, dry sieving is recommended".
- In subclause 4.5.3, change "If a combination of any of the sieving methods
is employed for different parts of the same overall size distribution, the
changeover from dry to wet sieving shall be clearly indicated on the report
sheet (see Clause 10)" TO "The choice of sieving method (see 4.5.5) for
each part of a size determination shall be made on the basis of attaining
the defined precision of testing (see 11.1). Details on the procedure shall
be recorded in the working log".
- Change the content of 4.7.1 "General" to "The loading of a sieve or nest of
sieves or continuous sieving machine shall be limited as prescribed in 4.7.2
and 4.7.3 a...