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This standard was proposed by State Bureau of Building Materials Industry and is under the jurisdiction of Qinhuangdao Glass Industry Research Institute of the State Bureau of Building Materials Industry.
This standard is drafted by Qinhuangdao Glass Industry Research Institute of the State Bureau of Building Materials Industry.
Chief drafters of this standard: Wang Zuozhou and Zhang Jiayi.
Methods for chemical analysis of glass making sands
This standard is applicable to chemical component analysis of silica, sandstone, silica sand and other glass making sands. Different analytical methods listed for the same component in the standard may be selected according to specific conditions.
1 General provisions
1.1 The analytical balance used shall be accurate to 0.0001g, and the balance and weight shall be subjected to regular check. When weighing the specimen, the reading shall be accurate to 0.0001g. "Constant weight" means that the difference between two consecutive weights is not more than 0.0002g.
1.2 The apparatus used shall be calibrated.
1.3 The analytical specimen shall be dried in an oven at 105~110°C for more than 1h, then put into a desiccator, cooled to room temperature and weighed.
1.4 Either distilled water or deionized water shall be used for analysis; the reagents used shall be analytical grade or guaranteed grade; the reagent used to calibrate the concentration of solution shall be the reference reagent. Blank test shall be done for water and reagents.
1.5 The concentration of reagent in the standard is expressed as follows:
1.5.1 When the acid and ammonium hydroxide are directly expressed by name, they refer to the concentrated reagents meeting the following percentage concentration.
Reagent
Hydrochloric acid
Hydrofluoric acid
Nitric acid
Perchloric acid
Sulfuric acid
Ammonium hydroxide Reagent concentration, %
36~38
More than 40
65~68
70~72
95~98
25~28
1.5.2 The concentrations of diluted acid and ammonium hydroxide are such expressed: e.g., hydrochloric acid (5+95) means a solution of 5 portions by volume of hydrochloric acid (36%~38%) with 95 portions by volume of water.
1.5.3 The concentration of the solution prepared by the solid reagent is expressed by weight/volume percentage (except for being used as standard solution). For example, 20% potassium hydroxide refers to a solution prepared by dissolving 20g of potassium hydroxide in 100ml of water. Unless otherwise specified, they all refer to aqueous solution.
1.6 The reference solution for photometric measurement is described as follows:
1.6.1 The "reagent blank solution" used in making standard curve refers to the solution without oxide to be measured in the first volumetric flask.
1.6.2 The "reagent blank solution" used in specimen analysis refers to the solution without specimen prepared according to the the specimen determination procedures.
2 Specimen preparation
The specimen taken must be mixed evenly, and shall represent the average composition, without foreign matters. Such specimen is divided into about 20g portion. It is ground in agate mortar until it passes through the sieve with mesh size of 75μm, and then put in weighing bottle for later use.
3 Determination of ignition loss
Weigh about 1g of specimen, place it into a platinum crucible with constant weight, put them into a high-temperature electric furnace, heat it up from room temperature, and calcine it at 1,000~1,050°C for 0.5h. Cool it down to room temperature in a desiccator, weigh, and calcine repeatedly until the weight is constant. The percentage content of ignition loss (X) shall be calculated using the following equation:
(1)
where,
G——the weight of specimen before calcination, g;
G1——the weight of specimen after calcination, g.
4 Determination of silicon dioxide
4.1 Hydrochloric acid dehydration gravimetry — spectrophotometry
4.1.1 Reagents
Anhydrous sodium carbonate;
Hydrochloric acid;
Hydrochloric acid: 1+1, 1+11, 5+95;
Sulfuric acid: 1+1;
Hydrofluoric acid;
2% potassium fluoride solution: weigh 2g of potassium fluoride (KF·2H2O), place it in a plastic cup, add 100ml of water to dissolve it, and store in a plastic bottle;
2% boric acid solution;
0.5% p-nitrophenol indicator ethanol solution: weigh 0.5g of p-nitrophenol and dissolve it in 100ml of 95% ethanol;
20% potassium hydroxide solution: weigh 20g of potassium hydroxide, place it in a plastic cup, add 100ml of water to dissolve it, and store in a plastic bottle;
95% ethanol;
8% ammonium molybdate solution: weigh 8g of ammonium molybdate, dissolve it in 100ml of water, filter it and store in a plastic bottle;
2% ascorbic acid solution (prepared just before use);
Silicon dioxide standard solution: accurately weigh 0.1000g of high-purity quartz (99.99%) which has been calcined at 1,000°C for 1h into a platinum crucible, add 2g of anhydrous sodium carbonate, and mix well. Heat it at low temperature, gradually raise the temperature to 1,000°C to obtain transparent melt, and cool it down. Soak the frit with hot water in a 300ml plastic cup, add 150ml of boiling water, stir to dissolve it (the solution shall be clear), and cool it down. Transfer it to a 1L volumetric flask, dilute with water to the mark, shake well, and immediately transfer it to a plastic bottle. This standard solution contains 0.1mg of silicon dioxide per milliliter.
4.1.2 Apparatus
Spectrophotometer.
4.1.3 Drawing of the standard curve of silicon dioxide (silicon molybdenum blue) colorimetry
Add 8ml of hydrochloric acid (1+11) and 10ml of water in a set of 100ml volumetric flasks respectively and shake well. Add 0ml, 1.00ml, 2.00ml, 3.00ml, 4.00ml, 5.00ml and 6.00ml of silicon dioxide standard solution with a graduated pipette respectively, add 8ml of 95% ethanol and 4ml of 8% ammonium molybdate, and shake well. When the room temperature is higher than 20°C, keep it resting for 15min; when it is lower than 20°C, place it in warm water at 30~50°C for 5~10min, and cool it down to room temperature. Add 15ml of hydrochloric acid (1+1), dilute it with water to nearly 90ml, add 5ml of 2% ascorbic acid, dilute with water to the mark, and shake well. One hour later, measure the absorbance of the solution with a spectrophotometer at the wavelength of 700nm in a 0.5cm cuvette with the reagent blank solution as reference. Draw the standard curve according to the relationship between the absorbance and the concentration of colorimetric solution.
4.1.4 Analytical procedures
Weigh about 0.5g of specimen in the platinum dish (the volume of the platinum dish is about 75~100ml), add 1.5g anhydrous sodium carbonate, mix with the specimen, and then spread 0.5g anhydrous sodium carbonate on the surface. First, heat at low temperature, gradually raise the temperature to 1,000°C, melt into transparent melt, and continue to melt for about 5min. Clamp the platinum dish with crucible pliers with platinum head, and rotate carefully to make the melt uniformly adhere to the inner wall of the dish. Cool it, cover the watch glass, and add 20ml of hydrochloric acid (1+1) to dissolve the frit. Heat the dish in a water bath until the carbonate is completely decomposed without bubbles. Take it off and wash the watch glass with hot water. Remove the watch glass, and put the platinum dish in a water bath to evaporate until it has no salt and sour taste.
Cool it, add 5ml of hydrochloric acid, keep it resting for about 5min, add about 20ml of hot water, stirring to dissolve salts, add appropriate amount of filter paper pulp and stir. Filter with medium-speed quantitative filter paper, take the filtrate and washing liquid with 250ml volumetric flask, wash the dish wall and precipitation with hot hydrochloric acid (5+95) for 10~12 times, and wash with hot water for 10~12 times.
Add 2 drops of sulfuric acid (1+1) to the precipitation, transfer the filter paper and the precipitation into the platinum crucible, put them on the electric furnace for low-temperature drying, and raise the temperature to ash the filter paper fully. Calcine it at 1,100°C for 1h, cool to room temperature in a desiccator, weigh, and repeatedly calcine it until the weight is constant.
Wet the precipitation with water, add 3 drops of sulfuric acid (1+1) and 5~7ml of hydrofluoric acid, heat on the sand bath, evaporate to dryness, repeat the treatment once, and continue heating until the white smoke of sulfur trioxide is exhausted. Calcine the crucible at 1,100°C for 15min, cool it to room temperature in a desiccator, and weigh it. Calcine it repeatedly until constant.
Dilute the above filtrate with water to the mark, and shake well. Pipette 25ml of filtrate, pour it into 100ml plastic cup, add 5ml of 2% potassium fluoride, shake well, and let it stand for 10min. Add 5ml of 2% boric acid, add 1 drop of p-nitrophenol indicator, add 20% potassium hydroxide dropwise until the solution turns yellow, add 8ml of hydrochloric acid (1+11), transfer it to a 100ml volumetric flask, add 8ml of 95% ethanol and 4ml of 8% ammonium molybdate, and shake well. When the room temperature is higher than 20°C, keep it resting for 15min; when it is lower than 20°C, place it in warm water at 30~50°C for 5~10min, and cool it down to room temperature. Add 15ml of hydrochloric acid (1+1), dilute it with water to nearly 90ml, add 5ml of 2% ascorbic acid, dilute with water to the mark, and shake well. One hour later, measure the absorbance of the solution with a spectrophotometer at the wavelength of 700nm in a 0.5cm cuvette with the reagent blank solution as reference.
Foreword i
1 General provisions
2 Specimen preparation
3 Determination of ignition loss
4 Determination of silicon dioxide
5 Determination of aluminum oxide
6 Determination of ferric oxide
7 Determination of titanium dioxide
8 Determination of calcium oxide
9 Determination of magnesium oxide
10 Determination of potassium oxide and sodium oxide
11 Determination of chromic oxide
12 Requirements for analysis results;
Annex A Determination of ferric oxide, calcium oxide, magnesium oxide, potassium oxide and sodium oxide by atomic absorption spectrophotometry (Supplement)
Annex B Determination of silicon dioxide by volatilization method and volumetric method (Informative)
Annex C Determination of potassium oxide and sodium oxide by ion selective electrode method (Informative)
Annex D Notes on allowable error (Informative)
Annex E Standard sand (Informative)
