GB/T 20975.36-2020Methods for chemical analysis of aluminium and aluminium alloys—Part 36:Determination of silver content—Flame atomic absorption spectrometry (English PDF)

Foreword

GB/T 20975 "Methods for Chemical Analysis of Aluminum and Aluminum Alloys" is divided into 37 parts.

---Part 1: Determination of mercury content;

---Part 2: Determination of arsenic content;

---Part 3: Determination of copper content;

---Part 4: Determination of iron content;

---Part 5: Determination of silicon content;

---Part 6: Determination of cadmium content;

---Part 7: Determination of manganese content;

---Part 8: Determination of zinc content;

---Part 9: Determination of lithium content by flame atomic absorption spectrometry;

---Part 10: Determination of tin content;

---Part 11: Determination of lead content;

---Part 12: Determination of titanium content;

---Part 13: Determination of vanadium content;

---Part 14: Determination of nickel content;

---Part 15: Determination of boron content;

---Part 16: Determination of magnesium content;

---Part 17: Determination of strontium content;

---Part 18: Determination of chromium content;

---Part 19: Determination of Zirconium Content;

---Part 20: Determination of Gallium Content Butyl Rhodamine B Spectrophotometry;

---Part 21: Determination of calcium content;

---Part 22: Determination of beryllium content;

---Part 23: Determination of antimony content;

---Part 24: Determination of total rare earth content;

---Part 25: Determination of element content by inductively coupled plasma atomic emission spectrometry;

---Part 26: Determination of carbon content by infrared absorption method;

---Part 27: Determination of cerium, lanthanum and scandium content by inductively coupled plasma atomic emission spectrometry;

---Part 28: Determination of cobalt content by flame atomic absorption spectrometry;

---Part 29: Determination of molybdenum content thiocyanate spectrophotometric method;

---Part 30: Determination of hydrogen content by heating extraction thermal conductivity method;

---Part 31: Determination of phosphorus content molybdenum blue spectrophotometric method;

---Part 32: Determination of Bismuth Content;

---Part 33: Determination of potassium content by flame atomic absorption spectrometry;

---Part 34: Determination of sodium content by flame atomic absorption spectrometry;

---Part 35: Determination of Tungsten Content Thiocyanate Spectrophotometric Method;

---Part 36: Determination of silver content by flame atomic absorption spectrometry;

--- Part 37: Determination of Niobium Content.

This part is part 36 of GB/T 20975.

This section was drafted in accordance with the rules given in GB/T 1.1-2009.

1 Scope

This part of GB/T 20975 specifies the flame atomic absorption spectrometry for the determination of silver content in aluminum and aluminum alloys.

This section applies to the arbitration determination of silver content in aluminum and aluminum alloys. Flame atomic absorption spectrometry measurement range. 0.0050%~ 2.00%.

2 Normative references

The following documents are indispensable for the application of this document. For dated reference documents, only the dated version applies to this document. For undated references, the latest version (including all amendments) is used in this document.

GB/T 8005.2 Terminology of Aluminum and Aluminum Alloy Part 2: Chemical Analysis

GB/T 8170-2008 Numerical rounding rules and the expression and determination of limit values

3 Terms and definitions

The terms and definitions defined in GB/T 8005.2 apply to this document.

4 Method summary

The sample was dissolved with hydrochloric acid and nitric acid. In an acid medium, at the wavelength of 328.1nm of flame atomic absorption spectrometer, air-acetylene fire Flame, measuring the absorbance of silver to determine the silver content.

5 Reagents

Unless otherwise stated, only reagents and laboratory secondary water confirmed to be analytically pure are used in the analysis.

5.1 Hydrochloric acid (rho=1.19g/mL).

5.2 Nitric acid (rho=1.42g/mL).

5.3 Hydrochloric acid (1 1).

5.4 Nitric acid (1 1).

5.5 Hydrochloric acid (1 4).

5.6 Silver standard storage solution. weigh 0.5000g silver (wAg>=99.99%) into a 250mL beaker, add 20mL nitric acid (5.4), Cover with a watch glass, heat at low temperature to completely dissolve, remove and cool, transfer to a 500mL volumetric flask, add 40mL nitric acid (5.2), and dilute with water to Scale and mix well. 1mL of this solution contains 1mg of silver.

5.7 Silver standard solution. Pipette 10.00mL silver standard stock solution (5.6) into a.200mL volumetric flask, add 20mL nitric acid (5.2), Dilute to the mark with water and mix well. 1mL of this solution contains 50µg of silver.

6 Instruments

Atomic absorption spectrometer with silver hollow cathode lamp. The instrument should meet the following conditions.

---Characteristic concentration. In a solution consistent with the matrix of the measurement solution, the characteristic concentration of silver should not be greater than 0.03µg/mL.

---Precision. Use the highest concentration of standard solution to measure the absorbance 10 times, and the standard deviation should not exceed 1.0% of the average absorbance; Use the lowest concentration standard solution (not the "zero" concentration standard solution) to measure the absorbance 10 times, and the standard deviation should not exceed the highest The concentration standard solution is 0.5% of the average absorbance.

---Linear working curve. Divide the working curve into five equal sections according to the concentration, the difference between the absorbance difference of the highest section and the absorbance difference of the lowest section The ratio should not be less than 0.70.

7 Sample

Process the sample into chips not larger than 1mm.

8 Analysis steps

9 Test data processing

The silver content is calculated as the silver mass fraction wAg, calculated according to formula (1).

When the silver content is less than 1.00%, the calculation result retains two significant digits; when the silver content is >=1.00%, the calculation result is expressed to two decimal places Bit. The rounding of values shall be implemented in 3.2 and 3.3 of GB/T 8170-2008.

10 Precision

11 Test report

The test report should include the following.

a) Number and name of this part;

b) All necessary information about identification of samples, laboratory, analysis date, report date, etc.;

c) Express the test results in an appropriate form;

d) Abnormal phenomena during the test;

e) Signatures of review and approval personnel.