The sample repeat measurement results allow the difference as specified in the table below. Lead measurement allows for poor tolerance (% lead (% relative absolute > 0.1 30 <0.10.03)
1 Determination of lead in non-metallic ore (barite) | Testing | Analytical methods)
This method is suitable for the determination of lead in barite. Measuring range: 0.002%~0.1% lead.
2 Principle
It was extracted with a sodium carbonate solution, and the sample was melted with sodium carbonate. A large amount of sulfate was separated by filtration, and the precipitate was dissolved in hydrochloric acid, and evaporated to dryness to dehydrate the silicon. Then, in the nitric acid (5+95 medium, the amount of lead is determined by atomic absorption spectrometry. The solution can also be used for the determination of copper and bismuth.
3 reagents
3.1 Anhydrous sodium carbonate.
3.2 Hydrochloric acid (Ï 1.19g/mL
3.3 Hydrochloric acid ( 1+4 3.4 nitric acid ( 1+1
Dissolved in 500mL of water. 3.5 Sodium carbonate solution: Weigh 10 g of sodium carbonate.
Dissolved in 100mL water. 3.6 Barium chloride solution: Weigh 10 g of barium chloride.
Wash separately with water and absolute ethanol, 3.7 lead standard solution: weigh 0.1000g to 0.0001g of metal lead [pre-use nitric acid (1+9 wash surface. dry in a desiccator for use) in a 250mL beaker Add 20mL of nitric acid (1+1 cover the watch glass, dissolve it by heating, transfer it into a 1000mL volumetric flask, dilute with water to the mark, shake it. 1mL of this solution contains 100 μg of lead. Take 50.00mL of lead standard solution and put it in 250mL In a volumetric flask, dilute to the mark with water and shake well. 1 mL of this solution contains 20 μg of lead (for working curve)
4 instruments (non-metallic ore (barite) lead determination | detection | analytical methods)
4.1 Atomic absorption spectrophotometer.
4.2 Lead hollow cathode lamp.
5 sample preparation
Cool to room temperature. The particle size should be less than 74 μm and pre-dried at 105 °C for 2h~4h in a desiccator.
6 Method of operation
6.1 Blank test A blank test is carried out along with the sample.
6.2 Determination
Add 4g~5g anhydrous sodium carbonate, 6.2.1 Weigh 0.1000g~0.5000g sample (accurate to 0.0001g in platinum crucible. Stir well, cover with a layer of anhydrous sodium carbonate, cover, put into high temperature In the furnace, it is cooled from low temperature to 1000 ° C for 30 min and taken out slightly cold. Platinum crucible is placed in a 250 mL beaker pre-filled with 50 mL of sodium carbonate solution, heated and extracted, and stirred to crush the frit. The platinum crucible and the lid are washed with water. Boil, cool, filter with slow filter paper and add a little pulp, wash the beaker with sodium carbonate solution and precipitate to the sulfate-free ion (about 10 times ~ 15 times, check with barium chloride solution) and discard the filtrate.
Leave a small slit, 6.2.2 The top of the funnel is covered with a watch glass. Carefully add about 30mL~40mL of hot hydrochloric acid from the gap (1+4 dissolve the precipitate in the original beaker, wash off the outer watch with water, remove it, wash the filter paper with hot water until all the cesium ions are washed.
Add a few drops of hydrochloric acid (Ï 1.19g/mL wetting residue, 6.2.3 Place the solution on a hot plate and heat to dry the silica to dehydrate the silica. Then add 10mL of nitric acid (1+1 and 20mL water, boil and dissolve the salt, Transfer to a 100mL volumetric flask, dilute to the mark with water, shake well, and place the clear. The solution is used for the determination of lead, and can also be used for the determination of bismuth and copper.
Directly measure or fractionate 10.00 mL~50.00 mL of the solution into a 100 mL volumetric flask, and 6.2.4 according to the content of lead in the sample. Add appropriate amount of nitric acid (1+1 so that the concentration of nitric acid in the final solution of zui is (5+95 diluted with water to the mark, shake well.
At a wavelength of 283.3 nm, 6.2.5 selected operating conditions on an atomic absorption spectrophotometer. The absorbance of lead was measured and the corresponding amount of lead was found from the working curve. 6.2.6 The working curve is drawn as 0 0.50 1.00 2.00 3.00 4.00 5.00mL The lead specification solution is placed in a 100mL volumetric flask, add 10mL of nitric acid (1+1 diluted with water to the mark, shake well. Operate according to 6.2.5 operation method, Draw a lead working curve.
7 Allowable difference (non-metallic ore (barite) lead determination | detection | analytical method)
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