GB/T 1617-2002Barium chloride for industrial use (English PDF)

6.2 The chemical composition content and grades of barium chloride for industrial use

shall comply with the provisions of Table 1.

Table 1

7.1 General provisions

The reagents and water used in this document, unless otherwise specified with other requirements, refer to analytical reagents and Grade 3 water specified in Table 1 of

GB/T 6682-2008.The standard titration solutions, impurity standard solutions, preparations and products for tests, unless otherwise specified with other requirements, shall be prepared according to the provisions of HG/T 3696.1, HG/T 3696.2 and HG/T

3696.3.

7.2 Appearance inspection

The appearance shall be inspected by visual method under natural light on a watch glass with a white background or a white porcelain plate.

7.3 Determination of barium chloride content

7.3.1 Barium chromate gravimetric method (arbitration method)

7.3.1.1 Principle

Use ammonium acetate to adjust the pH of the solution. In ammonium acetate solution and ammonia solution, potassium dichromate and barium chloride uniformly generate barium chromate precipitate. Calculate the content of barium chloride according to the mass of barium chromate precipitate.

7.3.1.2 Reagents or materials

7.3.1.2.1 Hydrochloric acid solution. 1+11.

7.3.1.2.2 Potassium dichromate solution. 50 g/L.

7.3.1.2.3 Ammonium acetate solution. 75 g/L.

7.3.1.2.4 Ammonia solution. 1+27.

7.3.1.2.5 Silver nitrate solution. 17 g/L.

7.3.1.3 Instruments and apparatuses

7.3.1.3.1 Glass sand crucible. Filter plate pore size 5 µm ~ 15 µm.

7.3.1.3.2 Electrically heated constant-temperature drying oven. Temperature controlled at 133 °C±2 °C.

7.3.1.4 Test procedure

Weigh approximately 7 g of the sample, accurate to 0.000 2 g; place it in a beaker; add water to dissolve; transfer into a 500 mL volumetric flask; use water to dilute to the mark; shake well; dry filter; discard the first 25 mL of filtrate. Pipette 50 mL of the filtrate into a 400 mL beaker. Add 5 mL of hydrochloric acid solution; add 100 mL of water and 15 mL of potassium dichromate solution; heat to boiling. Under the condition of slight boiling, while stirring, slowly add 10 mL of ammonium acetate solution dropwise (complete the addition within 3 min ~ 4 min); keep warm for 5 min; continue to add 15 mL of ammonia solution dropwise while stirring under slight boiling condition (complete the addition within 2 min ~ 3 min). Allow to stand for 30 min in a water bath at about 80 °C, then take out and rapidly cool to room temperature. Use a glass sand crucible that has been dried at 133 °C±2 °C to constant mass for suction filtration; use distilled water containing a small amount of ammonia solution (pH 7 ~ 8) to wash the precipitate until no chloride ion reaction occurs (checked with silver nitrate solution); dry the glass sand crucible and precipitate at 133 °C±2 °C to constant mass.

7.3.1.5 Test data processing

The content of barium chloride is expressed as the mass fraction w1 of barium chloride (BaCl2·2H2O), and is calculated according to Formula (1).

Where.

m1 – the mass value of barium chromate and glass sand crucible after drying, in grams (g);

m2 – the mass value of the glass sand crucible, in grams (g);

m – the mass value of the test sample, in grams (g);

0.964 2 – the conversion factor of barium chromate (BaCrO4) to barium chloride (BaCl2·2H2O).

Take the arithmetic mean of two parallel determination results as the determination result. The absolute difference between the two parallel determination results shall not be greater than 0.2%.

7.3.2 Barium sulfate gravimetric method

7.3.2.1 Principle

Under acidic conditions, the test sample solution reacts with sulfuric acid, causing Ba²^+ to be completely converted into barium sulfate. Calculate the content of barium chloride according to the mass of barium sulfate.

7.3.2.2 Reagents or materials

7.3.2.2.1 Hydrochloric acid solution. 1+1.

7.3.2.2.2 Sulfuric acid solution. 1+15.

7.3.2.2.3 Silver nitrate solution. 17 g/L.

7.3.2.3 Instruments and apparatuses

7.3.2.3.1 High-temperature furnace. The temperature can be controlled at 800 °C±20 °C.

7.3.2.3.2 Electrically heated constant-temperature water bath. The temperature can be controlled at 78 °C ~ 82 °C.

7.3.2.4 Test procedure

Weigh 0.6 g of the test sample, accurate to 0.000 2 g; place it into a 300 mL beaker; add

30 mL of water and 2 mL of hydrochloric acid solution; heat the solution to boiling; use slow-speed quantitative filter paper for filtration; use hot water to wash the residue until no chloride ions are present (checked with silver nitrate solution). Collect the filtrate and washing liquid into a 500 mL beaker; add water until the solution volume is approximately 300 mL. Under stirring, add 10 mL of hot sulfuric acid solution at a uniform rate; cover with a watch glass. Transfer to a constant-temperature water bath at approximately 80 °C and keep warm for 1 h. Then use slow-speed quantitative filter paper for filtration; use hot water to wash the precipitate until the filtrate has no chloride ions (checked with silver nitrate solution). Place the precipitate together with the filter paper into a porcelain crucible which has been previously ignited at 800 °C±20 °C to constant mass; dry and ash at low temperature on an electric furnace; then place in a high-temperature furnace at 800 °C±20 °C and ignite to constant mass.

7.3.2.5 Test data processing

The content of barium chloride is expressed as the mass fraction w1 of barium chloride (BaCl2·2H2O), and is calculated according to Formula (2).

Where.

m3 – the mass value of the precipitate and porcelain crucible, in grams (g);

m4 – the mass value of the porcelain crucible, in grams (g);

m – the mass of the sample, in grams (g);

w2 – the mass fraction of strontium in the test sample determined according to 7.4 or

7.10;

1.047 – the conversion factor of barium sulfate (BaSO4) to barium chloride (BaCl2·2H2O);

2.788 – the conversion factor of strontium (Sr) to barium chloride (BaCl2·2H2O).

Take the arithmetic mean of two parallel determination results as the determination result. The absolute difference between the two parallel determination results shall not be greater than 0.2%.

7.4 Determination of strontium content

7.4.1 Atomic absorption spectrophotometry (arbitration method)

7.4.1.1 Principle

Dissolve the test sample in water. In a hydrochloric acid medium, use the standard addition method, and use an air-acetylene flame to determine the strontium content at a wavelength of 460.7 nm by an atomic absorption spectrophotometer.

7.4.1.2 Reagents or materials

7.4.1.2.1 Hydrochloric acid solution. 1+11.

7.4.1.2.2 Potassium chloride solution. 10 g/L.

7.4.1.2.3 Strontium standard solution. 1 mL of solution contains 0.05 mg of strontium (Sr). Pipette 5 mL of the strontium standard stock solution prepared according to HG/T

3696.2; place into a 100 mL volumetric flask; use water to dilute to the mark; shake well. This solution shall be prepared immediately before use.

7.4.1.2.4 Water. Water conforming to the requirements of Grade 2 water specified in

GB/T 6682-2008.

7.4.1.3 Instruments and apparatuses

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