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GB/T 1575-2018 PDF in English

GB/T 1575-2018 (GB/T1575-2018, GBT 1575-2018, GBT1575-2018)
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GB/T 1575-2018: PDF in English (GBT 1575-2018)

GB/T 1575-2018
ICS 73.040
D 21
Replacing GB/T 1575-2001
Determination of yield of
benzene-soluble extract in brown coals
(ISO 975.2013, Brown coals and lignites - Determination of
yield of benzene-soluble extract - Semi-automatic method, MOD)
Issued by. General Administration of Quality Supervision, Inspection and
Standardization Administration of the People's Republic of
Table of Contents
Foreword ... 3 
1 Scope ... 4 
2 Normative references ... 4 
3 Method summary ... 4 
4 Reagents and materials ... 4 
5 Automatic extraction method ... 5 
6 Conical flask extractor method ... 8 
7 Calculation of results ... 10 
8 Method precision ... 10 
9 Test report ... 11 
Appendix A (Informative) Comparison between this standard clause number
and ISO 975.2013 clause number ... 12 
Appendix B (Informative) Technical differences between this standard and ISO
975.2013 and their causes ... 13 
This standard was drafted in accordance with the rules given in GB/T 1.1-2009.
This standard replaces GB/T 1575-2001 “Determination of yield of benzene-
soluble extract in brown coal”. As compared with GB/T 1575-2001, except for
editorial changes, the main technical content changes are as follows.
- MODIFY the size of the filter paper tube (see 4.2; 4.1 of 2001 version);
- ADD the blank test (see;
- MODIFY the calculation formula for the determination of the yield of
benzene-soluble extract in brown coals (see clause 6; clause 8 of the 2001
This standard uses the redrafting method to modify the use of ISO 975.2013
“Brown coals and lignites - Determination of yield of benzene-soluble extract -
Semi-automatic method”.
This standard has many structural adjustments than ISO 975.2013. Appendix A
lists the details of the clause number comparison of this standard with ISO
There are technical differences between this standard and ISO 975.2013. The
terms involved in these differences have been marked by a vertical single line
(|) at the margin of the outer margin, and a list of technical differences and their
causes are given in Appendix B.
This standard was proposed by the China Coal Industry Association.
This standard shall be under the jurisdiction of the National Coal
Standardization Technical Committee (SAC/TC 42).
Drafting organizations of this standard. Coal Science and Technology Research
Institute Co., Ltd. Testing Branch.
The main drafters of this standard. Wu Zengli, Chen Huizhu, Ma Kefu, Wang
This standard replaces the standard previously issued as follows.
- GB/T 1575-1979, GB/T 1575-1987, GB/T 1575-2001.
Determination of yield of
benzene-soluble extract in brown coals
1 Scope
This standard specifies the automatic extraction method and the conical flask
extraction method for the determination of benzene-soluble extract yield in
brown coal. The conical flask extraction method is the arbitration method.
This standard applies to brown coal.
2 Normative references
The following documents are essential to the application of this document. For
the dated documents, only the versions with the dates indicated are applicable
to this document; for the undated documents, only the latest version (including
all the amendments) are applicable to this standard.
GB/T 483 General rules for coal analysis test methods
3 Method summary
The coal sample is placed in an extractor and extracted with benzene. After the
coal sample is extracted with benzene, the benzene is distilled off, then the
solvent is distilled off and the extract is dried to a constant mass. The yield of
benzene-soluble extract in brown coal is calculated based on the extract mass.
4 Reagents and materials
Caution - Benzene is flammable, toxic, volatile, and may cause poisoning
in case of inhalation or skin contact with large amounts. The test must be
carried out in a fume hood.
Unless otherwise stated, only analytically pure reagents and distilled or
deionized water or water of comparable purity are used in the analysis.
4.1 Benzene. ρ = 0.876 g/mL, distillation range 80 ° C ~ 81 ° C, at least 95% is
distilled off.
4.2 Filter paper tube. φ25 mm x 80 mm, commercially available or made as Extraction test Weigh 2 g of general analytical test coal sample (accurate to 0.0002
g) which is mixed uniformly, put it into the filter paper tube, put a group of
absorbent cotton on the top of the paper tube and make the edge as close as
possible to the paper tube, place the filter paper tube with coal sample into the
extraction chamber. In a conical flask which is pre-dried to a constant mass and
weighed, add 60 mL ~ 70 mL of benzene. Connect all parts of the automatic
extractor. When the power is turned on and the program switch is pressed, the
instrument automatically performs extraction-rinsing-evaporation in accordance
with the preset procedure. The extraction-rinsing-evaporation device is lowered
until the conical flask is immersed in the water bath to a predetermined position,
the condenser is tilted until the benzene liquid can be dripped back to the
extraction chamber, the cooling water circulation device starts to work, at the
same time the water bath starts to heat. When the temperature rises to the pre-set extraction temperature, the
pump starts, the hot water in the water bath enters the extraction chamber
jacket, and circulates between the two, the benzene in the conical flask
evaporates to the condenser, condensates there, dripped back into the filter
paper tube of the extraction chamber, the extraction starts. After 180 min (or
other set time), the pump stops and the extraction ends. The extraction chamber is cooled by the hot water flowing back into
the water bath in the jacket, where the benzene vapor condenses and wash the
extract adhering to the inner wall of the extraction chamber into the conical flask,
the rinsing starts. After about 10 minutes, the rinsing is stopped, the condenser
is further tilted until the benzene liquid can flow out of the measuring system
and enter the recovery container, the pump starts again, the hot water enters
the extraction chamber jacket, the benzene vapor condenses in the condenser
and flows into the receiver, the evaporation starts. After about 50 minutes, the
evaporation ends and the extraction-rinsing-evaporation system raise to its
original position. Remove the conical flask with the extract and place it in an air drying
box at a temperature of 105 °C ~ 110 °C or a vacuum drying box at a
temperature of (80 ± 2) °C and a pressure of 50 kPa to dry it to constant mass.
Note. Generally, the first drying is 1.5 h, then the inspection drying is performed
for 30 min each time. When the mass difference between two consecutive
dryings is less than 0.0010 g, the mass is constant. Blank test
Except that no sample is added, the remaining steps are the same as
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.