Determination of chlorine (Cl)in color picture tube glass

SJ/T 10941-1996 Analysis of chlorine in color picture tube glass SJ/T10941-1996 standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Analysis of chlorine (Cl) in color picture tube glass
GB9474.6—88
Reduced to SJ/T10941-96
This standard specifies the analysis of chlorine and is applicable to the analysis of chlorine in electronic glass such as color picture tubes and black and white picture tube glass shells. This method should be analyzed in accordance with the provisions of GB9000.1 "General Principles of Chemical Analysis Methods for Electronic Glass". 1 Method Summary
The sample is melted with sodium carbonate and soaked with hot water. Insoluble matter is separated by filtration. Mercuric thioceric acid and ammonium ferric sulfate solution are added to the sample, and the content of trace chlorine in the glass is determined by measuring the absorbance of the ferric thiocyanate colorimetric solution formed by the thiocyanate ions replaced by nitrogen and iron. 2 Reagents and solutions ①
2.1 Sodium sulfate (superior grade);
2.2 Ammonium ferric sulfate solution 6%
Weigh 60g of ammonium ferric sulfate (superior grade) [Fe2(SO.): (NH.)2SO.·24H20) and dissolve it in nitric acid (6mol/L), and dilute it to 1000ml with nitric acid (6mol/L).
2.3 Mercuric thiocyanate ethanol solution 0.3%
Weigh 1.5g of mercuric thiocyanate [Hg(SCN)) and dissolve it in 500ml95% ethanol. 2.4 Nitric acid (superior grade) 1+2,6mol/L
2.5 Ethanol
2.6 Chloride ion standard solution 500ug/ml
Burn the standard sodium chloride at 500~600℃ for 40~50min, and place it in a desiccator to cool. Accurately weigh 0.8240g and dissolve it in water, transfer it into a 1000ml volumetric flask, dilute it to the mark with water, and shake it well. 2.7 Chloride ion standard dilution 5B/ml
Pipette 10ml of the chloride ion standard solution (2.6) into a 100ml volumetric flask, dilute it to the mark with water, and shake it well. Note: ① This method is extremely sensitive, and pollution such as sweat from hands or air in the laboratory may cause interference. Therefore, the purity of the reagents used should be as high as possible. Chlorine-free water is used throughout the analysis. It can be obtained by refining distilled water or deionized water through an ion exchange resin column 1 to 2 times. The exchange column uses highly regenerated (1-type) strong alkaline anion exchange resin and strongly acidic cation exchange resin in a ratio of (2:1) to form a resin layer with a height of more than 500mm. To finally determine whether it is usable, the conductivity should be measured with a flow-shaped conductivity cup. It can only be used if the value is below 0.15μV/cm (25℃).
3 Analysis steps
3.1 The sample is first coarsely crushed. Remove iron, grind it in an agate mortar, dry it at 110℃ for 1h, and cool it to room temperature in a desiccator. 3.2 Weigh 1.00g of the sample in a platinum dish, add 4g of anhydrous sodium carbonate, and mix well. Heat at low temperature, gradually increase the temperature, and finally melt it at 1000℃ until it is clear, and cool it.
3.3 Add 30ml of hot water to the platinum blood, place it in a water bath to heat and extract the molten material, filter it with slow quantitative filter paper, wash the precipitate with hot water 6~8 times, collect the filtrate and washing liquid in a 200ml beaker, add 20ml of nitric acid (1:2), heat and boil to drive out all the cyanide dioxide and control the volume of the solution to 60~70ml, and transfer it to a 100ml volumetric flask after cooling. 3.4 Use a pipette to add 10ml of ammonium ferric sulfate solution and 5ml of mercuric thiocyanate solution, shake it, keep it at 20±2℃ for 10min, dilute it with water to the scale, and shake it well. Use 2cm colorimetric blood with the reagent blank as the reference, measure the absorbance at a wavelength of 460nm, and find out the chlorine content in the test solution from the standard curve.
Note: ① The color development speed varies with the ambient temperature. Therefore, the temperature of the test solution after adding the reagent and the temperature when the standard working curve is prepared and the standard solution series is color developed should be as consistent as possible, and the temperature difference should be controlled within 2°C. ② Br\, I-, CN- and other ions in the reagent interfere with the determination, and S.O7, S\, and NO also interfere, but they can be eliminated if they are oxidized in advance. 3.5 Drawing of the standard curvebzxZ.net
Put 0, 102030, 40, 50ml of the chloride ion standard dilution solution into a set of 100ml volumetric flasks, and add water to about 60ml. The following analysis steps are carried out according to 3.4, the absorbance of the standard series solution is determined, and the relationship line between the chloride ion concentration and the absorbance is drawn as the standard curve. 4 Calculation
According to the measured absorbance of the sample solution, find the corresponding chlorine amount on the standard curve, and calculate the chlorine content in the sample according to the following formula. XX10-6
Wherein: X is the amount of chlorine in the sample solution found from the standard curve, uB; W is the sample weight, 8.
Additional Notes:
This standard was drafted by Factory 4400 of the Ministry of Electronics Industry and the Standardization Research Institute. 2
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