GB/T 10322.7-2016Iron ores and direct reduced iron -- Determination of size distribution by sieving (English PDF)

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 and requires previous information about the size distribution of

the sample to be sieved".

- The previous 4.7.2 corresponds to 4.7.2.1.And change "The maximum

mass retained shall not exceed the values tabulated in Annex A or as

determined in 4.7.2.1 or 4.7.2.2" TO "The maximum mass retained shall not

exceed the values tabulated in Annex C or as determined in 4.7.2.2 or

4.7.2.3".

- Change the previous "4.7.2.1 Apertures >= 500 µm" TO "4.7.2.2 Apertures >=

4 mm"; supplement the bulk density of the sample and measure it according

to ISO 3852.

- Change the previous "4.7.2.2 Apertures < 500 µm" TO "4.7.2.3 Apertures <

4 mm"; change "the maximum mass of sample retained shall not exceed 2

times the allowable maximum retention mass listed in Annex A" TO "the

maximum mass of sample retained shall be as given in Annex C".

- Delete "hand sieving time" from Table 2.

- Change the previous 6.2 "Acquisition of test sample(s) for division and

sieving" to "Mass of test sample(s) for sieving".

- Supplement "Table 3 Comparison of overall sizing precision, betaSPM, with the

precisions of sampling, betaS, and sample preparation and measurement, betaPM"

to the subclause 6.2.2.

- Change the previous 7.4.1 "General theory" to "General principles"; change

"22.4 mm" to "40 mm". Add the provision that "Of the above, the hand

sieving method performed in accordance with 7.4.3 or 7.4.4 is the reference

method that shall be used for bias assessments and in settling of between-

laboratory disputes".

- Change "22.4 mm" in the previous subclause 7.4.2 to "40 mm".

- Change "1 mm ~ 22.4 mm" in the previous subclause 7.4.3 to "1 mm ~ 40

mm", "60 times" to "120 times", and "amplitude 70 mm" to "120 mm".

- Add "applicable to round sieves with 200 mm and 300 mm diameters" to

the subclause 7.4.4.

- Supplement the provision that "Continuous sieving machines shall be

tested for bias in accordance with 5.2" to the subclause 7.4.7.

- Supplement "Table 4 Example of calculation and evaluation of results when

sieving a gross sample or test sample derived from the gross sample" and

"Table 5 Example of calculation and evaluation of results when sieving

several partial samples or increments" to the subclause 9.2.3.

- Uniformly change the words "specimens" and "samples" appearing in

subclause 9.3 to "test portions".

- Supplement the provision that "The median of four test results is defined as

the mean of the two non-extreme test results" to the subclause 9.3.7.

- In the subclause 9.3.8, change the previous "The value of r shall be 2 %

with reference to the specification size or other designated aperture sizes"

TO "The value of r shall be sqrt2 betaPM with reference to the specification size

or other designated aperture sizes".

- In subclause 11.1 Overall precision, change "It shall meet the requirements

of GB/T 10322.1" TO "This Part has been prepared with the aim of

satisfying the approximate overall precision requirements defined in ISO

3082 and ISO 10835.These precisions for sizing are set out in Table 6

below. The precision obtained in practice should be determined regularly

according to one of the protocols set out in ISO 3085".

- Supplement "Table 6 Overall precision of sizing, betaSPM" to the subclause 11.2

Precision of preparation and measurement.

- The previous Annex A is Annex C in this Part; the previous Annex B is Annex

G in this Part; the previous Annex G is Annex I in this Part. In this revision,

add Annex A "Steps for establishing the operating conditions for the

determination of size distribution using a single sieve or a nest of sieves",

Annex B "Scheme of sample preparation and sieving procedure", and

Annex J "Determination of the average particle size (APS)" to this Part.

This Part, using translation method, is identical to ISO 4701.2008 "Iron ores

and direct reduced iron - Determination of size distribution by sieving".

China's documents which have a consistent correspondence with the

international documents normatively referenced in this Part are as follows.

- GB/T 6003.1-2012 Test sieves - Technical requirements and testing - Part

1 Test sieves of metal wire cloth (ISO 3310-1.2000, MOD)

- GB/T 6003.2-2012 Test sieves - Technical requirements and testing - Part

2 Test sieves of metal wire cloth (ISO 3310-2.1999, MOD)

- GB/T 10322.1-2014 Iron ores - Sampling and sample preparation

procedures (ISO 3082.2009, IDT)

- GB/T 10322.3-2000 Iron ores - Experimental methods for checking the

precision of sampling (idt ISO 3085.1996)

- GB/T 10322.4-2014 Iron ores - Experimental methods for checking the bias

of sampling (ISO 3086.2006, IDT)

- GB/T 10322.5-2016 Iron ores - Determination of the moisture content of a

lot (ISO 3087.2011, IDT)

- GB/T 20565-2006 Iron ores and direct reduced iron - Vocabulary (ISO

11323.2002, IDT)

- GB/T 24239-2009 Direct reduced iron and hot briquetted iron - Sampling

and sample preparation (ISO 10835.2007, IDT)

This Part was proposed by China Iron and Steel Association.

This Part shall be under the jurisdiction of National Technical Committee 317

on Iron Ore and Direct Reduced Iron of Standardization Administration of China

(SAC/TC 317).

Drafting organizations of this Part. Shanghai Baosteel Industrial Technology

Services Co., Ltd., Baoshan Iron & Steel Co., Ltd., China Metallurgical

Information and Standardization Institute.

Main drafters of this Part. Wang Chunsheng, Chen Xiaoqi, Wang Han, Yu

Chengfeng, Ji Huadong, Chen Zibin.

The previous editions of the standard replaced by this Part were released as

follows.

- GB/T 10322.7-2004.

Iron ores and direct reduced iron - Determination of

size distribution by sieving

1 Scope

This Part of GB/T 10322 specifies the methods to be employed for

determination of size distributions of iron ore and direct reduced iron.

2 Normative references

The following documents are indispensable for the application of this document.

For the dated references, only the editions with the dates indicated are

applicable to this document. For the undated references, the latest edition

(including all the amendments) are applicable to this document.

3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 11323

apply.

4 Principles and planning

The principal purposes of particle size determination are as follows.

The sample may be received in the form of a gross sample, several partial

samples or increments.

5 Apparatus

When wet sieving is carried out, in addition to the apparatus mentioned in 5.1

and 5.2, it is necessary to have available a controllable supply of water, a spray

nozzle and, where appropriate, a collecting tank.

Each device for the determination of mass shall have a sensitivity of 0.1 % of

its rated capacity and a level of accuracy such that the mass of the test sample

and of each size fraction may be determined to a precision of ± 0.1 % or better

of the test sample mass.

6 Samples

The mass of the test samples used for sieving shall be equal to or greater than

the minimum mass defined in 6.2.2.

The level of precision, betaPM, to be used shall be determined so that the overall

precision specified in Table 3 shall be met.

7 Procedures

One or more of the following methods of sample division shall be conducted

individually or jointly; the applicability of each method for division of the

particular ore and DRI shall be determined by reference to ISO 3082 or ISO

10835.

8 Verification

The precision of any division procedures adopted during sieve size analysis

shall be determined and evaluated in accordance with ISO 3085.More frequent

checks shall be carried out on the critical parameters associated with the

adopted division method.

9 Results

If the range of these four size analyses do not agree within the limit 1.3 r,

the median of these four size analyses is taken to be representative of the lot.

The median of four test results is defined as the mean of the two non-extreme

test results.

10 Test report and working log

The test results shall be traceable and cover the following items.

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