GB/T 32786-2016 English PDF (GB/T32786-2016)

GB/T 32786-2016: Pig iron contenting nickel -- Determination of iron content -- Dichromate titration method
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GB/T 32786-2016
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 77.100
H 11
Pig iron contenting nickel - Determination of iron
content - Dichromate titration method
ISSUED ON: JUNE 14, 2016
IMPLEMENTED ON: MAY 01, 2017
Issued by: General Administration of Quality Supervision, Inspection and
Quarantine;
Standardization Administration of the People’s Republic of
China.
Table of Contents
Foreword ... 3 
1 Scope ... 4 
2 Normative references ... 4 
3 Principle ... 4 
4 Reagents ... 5 
5 Instruments ... 6 
6 Sample taking ... 6 
7 Analysis steps ... 6 
8 Result calculation ... 7 
9 Allowable difference ... 8 
10 Test report ... 8 
Pig iron contenting nickel - Determination of iron
content - Dichromate titration method
WARNING – The personnel who uses this Standard shall have hands-on
experience in formal laboratory work. This Standard does not address all
possible security issues. It is the responsibility of the user to take
appropriate safety and health measures and to ensure compliance with
the conditions which are set by the relevant national regulations.
1 Scope
This Standard specifies the potassium dichromate titration method for the
determination of iron content.
This Standard applies to the determination of iron content in pig iron contenting
nickel; the determination range (mass fraction): 65.00% ~ 90.00%.
2 Normative references
The following documents are indispensable for the application of this document.
For dated references, only the dated version applies to this document. For
undated references, the latest edition (including all amendments) applies to this
document.
GB/T 4010, Ferroalloys sampling and preparation of samples for chemical
analysis
GB/T 6682, Water for analytical laboratory use - Specification and test
methods
GB/T 12805, Laboratory glassware - Burettes
GB/T 12806, Laboratory glassware - One-mark volumetric flasks
GB/T 12808, Laboratory glassware - One mark pipettes
3 Principle
After the sample is decomposed by acid, the ammonia water precipitates iron.
In hydrochloric acid solution, use stannous chloride and titanium trichloride to
reduce iron to divalent. In the presence of the sulfuric acid-phosphoric acid
4.15 Potassium dichromate standard titration solution, c(ଵ଺K2Cr2O7) = 0.04 000
mol/L. Accurately weigh 1.961 2 g of potassium dichromate (reference) that has
been dried at 105 °C ± 5 °C for 1 h and cooled to room temperature in a 500
mL beaker; add 100 mL of water. After the potassium dichromate is fully
dissolved, transfer it to a 1 000 mL volumetric flask; use water to dilute to the
mark; mix well.
4.16 Sodium diphenylamine sulfonate indicator solution, 5g/L.
5 Instruments
Ordinary laboratory instruments; burettes, one-mark volumetric flasks, and one
mark pipettes shall meet the requirements of GB/T 12805, GB/T 12806 and
GB/T 12808, respectively.
6 Sample taking
Laboratory samples for analysis shall be taken and prepared in accordance with
GB/T 4010. The crushed and ground sample shall pass through the 0.125 mm
sieve; the drilled sample shall pass through the 1.68 mm sieve.
7 Analysis steps
7.1 Sample mass
Weigh 0.10 g of sample (see Chapter 6), to the nearest 0.000 1 g.
7.2 Number of determinations
Measure the same sample at least twice independently.
7.3 Blank test
Use the same amount of all reagents and follow the same procedure as the
sample to determine the blank test value. Before using stannous chloride
solution (4.10) for reduction and oxidation titration (7.4.2), use the one mark
pipette to pipette 2.00 mL of ammonium ferrous sulfate solution (4.14); titrate
the solution according to step 7.4.2. Record the consumed volume (V1). Then,
use the one mark pipette to transfer 2.00 mL of ammonium ferrous sulfate
solution (4.14); titrate the solution according to step 7.4.2. Record the
consumed volume (V2). Thus, obtain the reagent blank V0 for sample analysis
(i.e. V1 - V2).
GB/T 32786-2016
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 77.100
H 11
Pig iron contenting nickel - Determination of iron
content - Dichromate titration method
ISSUED ON: JUNE 14, 2016
IMPLEMENTED ON: MAY 01, 2017
Issued by: General Administration of Quality Supervision, Inspection and
Quarantine;
Standardization Administration of the People’s Republic of
China.
Table of Contents
Foreword ... 3 
1 Scope ... 4 
2 Normative references ... 4 
3 Principle ... 4 
4 Reagents ... 5 
5 Instruments ... 6 
6 Sample taking ... 6 
7 Analysis steps ... 6 
8 Result calculation ... 7 
9 Allowable difference ... 8 
10 Test report ... 8 
Pig iron contenting nickel - Determination of iron
content - Dichromate titration method
WARNING – The personnel who uses this Standard shall have hands-on
experience in formal laboratory work. This Standard does not address all
possible security issues. It is the responsibility of the user to take
appropriate safety and health measures and to ensure compliance with
the conditions which are set by the relevant national regulations.
1 Scope
This Standard specifies the potassium dichromate titration method for the
determination of iron content.
This Standard applies to the determination of iron content in pig iron contenting
nickel; the determination range (mass fraction): 65.00% ~ 90.00%.
2 Normative references
The following documents are indispensable for the application of this document.
For dated references, only the dated version applies to this document. For
undated references, the latest edition (including all amendments) applies to this
document.
GB/T 4010, Ferroalloys sampling and preparation of samples for chemical
analysis
GB/T 6682, Water for analytical laboratory use - Specification and test
methods
GB/T 12805, Laboratory glassware - Burettes
GB/T 12806, Laboratory glassware - One-mark volumetric flasks
GB/T 12808, Laboratory glassware - One mark pipettes
3 Principle
After the sample is decomposed by acid, the ammonia water precipitates iron.
In hydrochloric acid solution, use stannous chloride and titanium trichloride to
reduce iron to divalent. In the presence of the sulfuric acid-phosphoric acid
4.15 Potassium dichromate standard titration solution, c(ଵ଺K2Cr2O7) = 0.04 000
mol/L. Accurately weigh 1.961 2 g of potassium dichromate (reference) that has
been dried at 105 °C ± 5 °C for 1 h and cooled to room temperature in a 500
mL beaker; add 100 mL of water. After the potassium dichromate is fully
dissolved, transfer it to a 1 000 mL volumetric flask; use water to dilute to the
mark; mix well.
4.16 Sodium diphenylamine sulfonate indicator solution, 5g/L.
5 Instruments
Ordinary laboratory instruments; burettes, one-mark volumetric flasks, and one
mark pipettes shall meet the requirements of GB/T 12805, GB/T 12806 and
GB/T 12808, respectively.
6 Sample taking
Laboratory samples for analysis shall be taken and prepared in accordance with
GB/T 4010. The crushed and ground sample shall pass through the 0.125 mm
sieve; the drilled sample shall pass through the 1.68 mm sieve.
7 Analysis steps
7.1 Sample mass
Weigh 0.10 g of sample (see Chapter 6), to the nearest 0.000 1 g.
7.2 Number of determinations
Measure the same sample at least twice independently.
7.3 Blank test
Use the same amount of all reagents and follow the same procedure as the
sample to determine the blank test value. Before using stannous chloride
solution (4.10) for reduction and oxidation titration (7.4.2), use the one mark
pipette to pipette 2.00 mL of ammonium ferrous sulfate solution (4.14); titrate
the solution according to step 7.4.2. Record the consumed volume (V1). Then,
use the one mark pipette to transfer 2.00 mL of ammonium ferrous sulfate
solution (4.14); titrate the solution according to step 7.4.2. Record the
consumed volume (V2). Thus, obtain the reagent blank V0 for sample analysis
(i.e. V1 - V2).