HG/T 2520-2006Phosphorous acid for industrial use (English PDF)

4.4.1 Method summary

In nitric acid medium, chloride ions in test solution and silver nitrate form insoluble

silver chloride. When chloride ion content is low, within a certain time, the silver

chloride is shown in suspension, so that the solution is cloudy. The turbidity of the test

solution is compared with the standard turbidity solution.

4.4.2 Reagents

4.4.2.1 Nitric acid solution. 1 + 3.

4.4.2.2 Silver nitrate solution. 17 g/L.

4.4.2.3 Chloride standard solution. 1 mL of the solution contains 0.010 mg of chlorine

(Cl).

PIPETTE 1.00 mL of chloride standard solution that is prepared according to HG/T

3696.2 PLACE in 100 mL volumetric flask. USE water to dilute to the mark. SHAKE

evenly.

4.4.3 Analysis steps

For superior product, WEIGH (3.00±0.01) g of sample; for first-class product and

qualified product, WEIGH (0.50±0.01) g of sample. PLACE in 50mL colorimetric tubes.

ADD 20mL of water to dissolve. Then ADD 2 mL of nitric acid solution and 2 mL of

silver nitrate solution. USE water to dilute to the mark. SHAKE evenly. PLACE for

10min. The turbidity must not be greater than the standard turbidity solution.

The standard is – for superior product, PIPETTE 3.00mL of chloride standard solution;

for first-class product, PIPETTE 5.00mL of chloride standard solution; for qualified

product, PIPETTE 10.00mL of chloride standard solution. PLACE in 50mL colorimetric

tubes. It is treated as same as the test sample at the same time.

4.5 Determination of iron content

4.5.1 Method summary

Same as Chapter 2 of GB/T 3049-1986.

4.5.2 Reagents

Chapter 3 of GB/T 3049-1986 and;

4.5.2.1 Ammonia.

4.5.2.2 Hydrochloric acid solution. 2 + 3.

4.5.3 Instruments

The turbidity of the test solution is compared with the standard turbidity solution.

4.6.2 Reagents

4.6.2.1 Ammonia solution. 2 + 3.

4.6.2.2 Hydrochloric acid solution. 1 + 4.

4.6.2.3 Magnesium mixed solution. WEIGH 5.5 g of magnesium chloride and 7 g of

ammonium chloride. PLACE in 200 mL beaker. ADD 65 mL of water to dissolve. Then

ADD 35 mL of ammonia solution. PLACE for 24 h. FILTER if necessary.

4.6.2.4 Phosphate standard solution. 1 mL of solution contains 0.1 mg of phosphate

(PO4).

PIPETTE 10.00 mL of phosphate standard solution that is prepared according to

HG/T 3696.2.PLACE in 100 mL volumetric flask. USE water to dilute to the mark.

SHAKE evenly.

4.6.3 Analysis steps

4.6.3.1 Preparation of test solution

WEIGH (1.00±0.01) g of sample. PLACE in 100 mL volumetric flask. USE water to

dilute to the mark. SHAKE evenly.

4.6.3.2 Determination

PIPETTE 10mL od solution. PLACE in 25 mL colorimetric tube. ADD 5 mL of aqueous

ammonia solution and 5mL of magnesium mixture solution. USE water to dilute to the

mark. SHAKE evenly. PLACE for 10min. The turbidity shall not be greater than the

standard turbidity solution.

The standard is – for superior product, PIPETTE 1.00mL of chloride standard solution;

for first-class product, PIPETTE 2.00mL of chloride standard solution; for qualified

product, PIPETTE 6.00mL of phosphate standard solution. PLACE in 25mL

colorimetric tubes. USE hydrochloric acid solution to adjust pH~2.It is treated as

same as the test sample at the same time.

4.7 Determination of sulphate (counted in SO4) content

4.7.1 Method summary

In hydrochloric acid medium, sulphate in test solution and barium chloride form

insoluble barium sulphate and is shown in suspension, so that the solution is cloudy.

The turbidity of the test solution is compared with the standard turbidity solution.

4.7.2 Reagents

use shall comply with the requirements of the standard.

5.5 Use organization has the right to perform the acceptance inspection to the

phosphorous acid for industrial use in accordance with the requirements of this

standard. The acceptance shall be performed within 1 month from the date of arrival

of the goods.

5.6 If the test results in the indicators do not meet the requirements of this standard, it

shall be double-sampled from the packaging bags for re-inspection. In re-inspection

results, even if only one indicator does not meet the requirements of this standard, the

entire batch of product is deemed as unqualified.

5.7 ADOPT the rounding value comparison method specified in GB/T 1250 to

determine whether the inspection results meet this standard.

6.1 On drums or bags of phosphorous acid for industrial use, there must have firm

and clear signs. The contents include. manufacturer's name and address, product

name, trademark, grade, net content, lot number or production date, this standard

number, the "corrosive" signs specified in GB 190-1990, and the "Avoid rain" logo

specified in GB/T 191-2000.And it shall be accompanied with ""Dangerous Chemical

Material Safety Data Sheet" in the package.

6.2 Each batch of phosphorous acid for industrial use shall be accompanied with

quality certificates, including. manufacturer's name and address, product name,

trademark, grade, net content, lot number or production date, product quality

certificate that complies with this standard, and the number of this standard.

7.1 for packaging, phosphorous acid for industrial use shall adopt sealed and

fully-open barrels or high-intensity composite packaging bags that comply with the

relevant transportation safety requirements. The performance and inspection method

of each batch of packaging materials shall comply with the relevant provisions.

7.2 Drum-packaging of phosphorous acid for industrial use is in 3 layers. lined 2

layers are polyethylene bags; external packaging adopts sealed and fully-open

iron-barrels or fibreboard barrels. The 2 internal bags are tightened with Vinalon rope

or ropes with equivalent quality; or it is sealed with other corresponding ways.

Iron-barrels or fibreboard barrels are covered with a lid; clamped with clamping ring;

and pinned w...

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