GB/T 223.60-1997 English PDF (GBT223.60-1997)

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GB/T 223.60-1997: Methods for chemical analysis of iron, steel and alloy - The perchloric acid dehydration gravimetric method for the determination of silicon content
GB/T 223.60-1997
GB
NATIONAL STANDARD OF
THE PEOPLE’S REPUBLIC OF CHINA
Replacing GB 223.60-87
Methods for chemical analysis of iron, steel and alloy
- The perchloric acid dehydration gravimetric method
for the determination of silicon content
APPROVED ON. MARCH 17, 1997
IMPLEMENTED ON. SEPTEMBER 1, 1997
Issued by. China Bureau of Technical Supervision
Approved by. China Bureau of Technical Supervision
Table of Contents
Foreword ... 3 
1 Scope ... 4 
2 Normative references ... 4 
3 Method summary ... 4 
4 Reagents and materials ... 4 
5 Instruments and equipment ... 5 
6 Sampling and sample preparation ... 5 
7 Analysis procedures ... 5 
8 Analysis result and its expression ... 7 
9 Precision... 8 
10 Test report ... 8 
Annex A (Informative) Sample for precision test in perchloric acid dehydration
gravimetric method ... 10 
Annex B (Informative) Source data of precision test in perchloric acid
dehydration gravimetric method ... 11 
Foreword
This Standard was revised based on GB/T 1.1-1993 “Directives for the work
of standardization. Unit 1. Drafting and presentation of standards. Part 1.
General rules for drafting standards”, GB 1.4-88 "Directives for the Work of
Standardization-Rules for Drafting Chemical Analysis Standards" and GB
223.60-87 “Methods for chemical analysis of iron, steel and alloy - The
perchloric acid dehydration gravimetric method for the determination of silicon
content”.
According to the provisions of 4.2.3, 4.3.3 in Chapter 4 of GB/T 1.1-1993 and
6.10 of GB 1.4-88, "foreword", "Scope" in Chapter I, "Normative References"
in Chapter Two, "sampling and sample preparation" in Chapter 6 and "test
report" in Chapter 10.
The Appendix A and Appendix B of this Standard are informative.
This Standard replaces GB 223.60-87 when it comes into force.
This Standard was proposed by the Ministry of Metallurgical Industry of the
People's Republic of China.
This Standard shall be under the jurisdiction of National Technical Committee
on Iron and Steel of Standardization Administration of China.
The drafting organization of this Standard. Central Iron and Steel Research
Institute, Ministry of Metallurgical Industry.
Main drafters of this Standard. Wang Yuxing and Cui Qiuhong.
This Standard was issued as GB 223.5 (1)-81 in 1981 for the first time,
revised to GB 223.60-87 in 1987 and determined the method accuracy.
Methods for chemical analysis of iron, steel and alloy
- The perchloric acid dehydration gravimetric method
for the determination of silicon content
1 Scope
This Standard specifies the perchloric acid dehydration gravimetric method
for the determination of silicon content in iron, steel, high temperature alloy
and precious alloy.
This Standard is applicable to determination of 0.10%(m/m) ~ 6.00%(m/m)
silicon content in iron, steel, high temperature alloy and precious alloy.
2 Normative references
The following standards contain provisions which, through reference in this
text, constitute provisions of this Standard. As all the standards will be revised,
each party using this Standard shall discuss the feasibility of using the latest
edition of the following standards.
GB/T 222-84, Method of Sampling Steel for Determination of Chemical
Composition and Permissible Variations for Product Analysis
GB 6379-86, Precision of Test Methods. Determination of Repeatability
and Reproducibility for a Standard Test Method by Interlaboratory Tests
3 Method summary
Dissolve the specimen with hydrochloric acid and nitric acid dissolution,
dehydrate silicic acid with perchloric acid smoking, filter and clean the silicic
acid and then firing it into silicon dioxide. Handle it with sulfuric acid
-hydrofluoric acid, make it produce silicon tetrafluoride which is volatilized and
removed. Calculate the silicon contents according to the mass difference after
the removal of silicon.
4 Reagents and materials
4.1 Hydrochloric acid (ρ1.19 g/mL).
4.2 Hydrochloric acid (5+95), dilute it with hydrochloric acid (4.1).
4.3 Nitric acid (ρ1.42 g/mL).
4.4 Perchloric acid (ρ1.67 g/mL).
4.5 Hydrofluoric acid (ρ1.15 g/mL) .
4.6 Methanol.
4.7 Sulfuric acid (1+1) dilutes it with sulfuric acid (ρ1.84 g/mL).
4.8 Ammonium thiocyanate solution (50 g/L).
5 Instruments and equipment
In analysis, only use ordinary laboratory appliance and equipment except the
following specifications.
5.1 Platinum crucible with volume of 30 mL.
5.2 Muffle furnace with the adjustable temperature range of 500°C ~
1100°C.
6 Sampling and sample preparation
Sampling and sample preparation is according to GB 222 or corresponding
national standard about iron.
7 Analysis procedures
Safety instruction. perchloric acid smoke may cause explosion if the ammonia
oxide and nitrogen oxide or organic matter are available.
Hydrofluoric acid can burn human body severely, so medical gloves shall be
worn when using it and immediately wash your hands after using it.
7.1 Quantity of sample material
Weigh sample according to Table1.
Table 1 -- Sample material quantity
Silicon content,%(m/m) Test portion, g
0.10~0.50 4.0±0.1, accuracy of 10 mg
>0.50~1.00 3.0±0.1, accurate to 5 mg
>1.00~2.00 2.00±0.01, accuracy of 1 mg
>2.00~4.00 1.00±0.01, accuracy of 0.1 mg
>4.00~6.00 0.50±0.01, accuracy of 0.1 mg
7.2 Blank test
Parallel to the determination of the specimen and make the blank test shall be
carried out in the identical operation method. All reagents and the dose are
completely identical with those of the specimen determination.
7.3 Determination
7.3.1 Material dissolution
Place the specimen (7.1) into a 400-mL beaker, add 30 mL ~ 60 mL of mixed
acid of hydrochloric acid (4.1) and nitric acid (4.3) . Put on the watch glass,
and heat it slowly until the specimen is dissolved completely (if the boron
content in boron steel is larger than 1% or the boron content is larger than
0.01% and silicon content is larger than 1%, the boron shall be removed.
After the specimen is dissolved, heat and concentrate the test solution until its
volume reaches about 10 mL, add 40mL of methanol (4.6), move the watch
glass to let out a little interspace, volatilize the solution slowly at low
temperature until it volume is less than 10 mL). Add 5 mL of nitric acid (4.3).
Take it out and cool it down for a while, and then wash the watch glass and
wall of glass with small amount of water.
Add perchloric acid (4.4) according to those specified in Table 2 and
heat/evaporate it until the fume appears, cover the watch glass and continue
to heat it and make perchloric acid flow back for 15min ~ 25min.
Table 2 -- Perchloric acid amount
Test portion (7.1), g Perchloric acid (4.4) volume added, mL
4.0±0.1 55
3.0±0.1 45
2.00±0.01 35
1.00±0.01 25
0.50±0.01 20
Note.
1 Proportion of hydrochloric acid (4.1)-nitric acid (4.3) mixed acid is determined according
to sample. As for the samples which contain high chromium and indissoluble mixed acid,
dissolve them with hydrochloric acid (4.1), then oxidize with nitric acid (4.3).
2 As for the samples containing high wolfram and molybdenum, shake them more in the
process of dissolution, especially near syrup state, and then oxidize them with nitric acid
(4.3).
7.3.2 Take it out and cool a while, moisten salt with 6 mL of hydrochloric
acid, deoxidize them with sexavalent chrome, add 100 mL of hot water,
stirring,...