GB/T 5195.6-1985 Chemical analysis methods for fluorite - Molybdenum blue spectrophotometric method for determination of phosphorus content

GB/T 5195.6-1985 Chemical analysis method of fluorite - Determination of phosphorus content by molybdenum blue spectrophotometry GB/T5195.6-1985 standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Chemical analysis method of fluorspar
Determination of phosphorus content by molybdenum blue spectrophotometry
Methods for chemical analysis of fluorsparThe molybdenum blue photometric methodfor the determination of phosphorus contentThis standard is applicable to the determination of phosphorus content in fluorspar. Determination range: 0.002～0.50%. This standard complies with GB1467-78 "General Principles and General Provisions of Standards for Chemical Analysis Methods of Metallurgical Products", 1 Method Summarywww.bzxz.net
UDC549.454
GB5195.6--85
The sample is dissolved with fluoric acid and perchloric acid. Ammonium molybdate and phosphorus are added to 1N hydrochloric acid medium to generate phosphomolybdic acid heteropolyacid, and ascorbic acid hydrochloric acid hydroxylamine is used to reduce the phosphomolybdic acid heteropolyacid to phosphomolybdic acid. Its absorbance is measured at a wavelength of 800nm ​​on a spectrophotometer. 2 Reagents
2.1 Hydrofluoric acid (specific gravity 1.13): high-grade pure. 2.2 Perchloric acid (specific gravity 1.67): high-grade pure. 2.3 Hydrobromic acid (specific gravity 1.38): high-grade pure. 2.4 Hydrochloric acid (specific gravity 1.19).
2.5 Hydrochloric acid (1+1)
2.6 Mixed reducing agent: Mix two parts of 5% ascorbic acid with one part of 5% hydroxylamine hydrochloride solution. Prepare on the same day. 2.7 Ammonium molybdate [(NH)6MoO244H,O solution (4%): Weigh 4g of ammonium molybdate and place it in a beaker, add appropriate amount of water, heat to dissolve, cool to room temperature, dilute with water to 100ml, mix well, and filter. 2.8 Phosphorus standard stock solution: Weigh 4.3937g of potassium hydrogen phosphate (reference reagent) that has been dried at 105-110℃ for 2h and placed in a desiccator to cool to room temperature. After the solution is completely dissolved in an appropriate amount of water, transfer it to a 1000ml volumetric flask, dilute it to the mark with water, and mix it. This solution contains 1 mg phosphorus in 1 ml.
2.9 Phosphorus standard solution: Transfer 10.00ml of phosphorus standard storage solution (2.8) to a 1000ml volumetric flask, dilute it to the mark with water, and mix it. This solution contains 0.01mg phosphorus in 1ml. 3 Instruments
Spectrophotometer.
4 Sample
4.1 The sample should pass through a 240mm sieve.
4.2 The sample should be dried at 105±1℃+ for 2h, and then placed in a desiccator to cool to room temperature. 5 Analysis steps
5.1 Determination quantity
Three samples should be weighed for determination during analysis, and the average value should be taken. Issued by the National Bureau of Standards on May 18, 1985
Implemented on March 1, 1986
5.2 Sample quantity
Weigh the sample as specified in Table 1.
0.002~0.02
>0.02~0.50
5.3 Blank test
Carry out a blank test with the sample.
5.4 Determination
GB 5195.6—85
5.4.1 Place the sample (5.2) in a 35ml polytetrafluoroethylene or platinum crucible. Test
5.4.2 Add 4ml hydrofluoric acid (2.1), heat at low temperature to dissolve, evaporate to nearly T, add 2ml hydrofluoric acid (2.1), continue to evaporate to nearly ten, and cool slightly.
5.4.3 Add 3 ml hydrochloric acid (2.4) and 0.5 ml hydrobromic acid (2.3), evaporate to near dryness, and cool slightly. 5.4.4 Add 2 ml perchloric acid (2.2), evaporate to near dryness, and cool slightly. Add 7 ml hydrochloric acid (2.5), heat until the salts are dissolved, cool to room temperature, and transfer to a 50 ml volumetric flask. 5.4.5 Transfer the sample solution according to Table 2, add hydrochloric acid (2.5), and place in another 50 ml volumetric flask. Table 2
0.002 ~ 0.02
>0.02~0.05
>0.05 ~0.10
>0.10~0.50
Sample plate
Sample amount
Additional amount of hydrochloric acid (2.5)
5.4.6 Add 3ml of mixed reducing agent (2.6), mix well, dilute with water to about 35ml, add 4ml of ammonium molybdate solution (2.7) while shaking, rinse the bottleneck with water, place in a boiling water bath and heat for 5min, remove the running water and cool to room temperature, dilute with water to the scale, and mix well. 5.4.7 Transfer part of the solution to a 1cm colorimetric dish, use the blank accompanying the sample as a reference, measure its absorbance at a wavelength of 800nm ​​on the spectrophotometer, and find the corresponding phosphorus amount from the working curve. 5.5 Drawing of working curve
Pipette 0.00, 0.50, 1.00, 2.00, 3.00, 4.00, 5.00 ml of phosphorus standard solution (2.9) and place them in 50 ml volumetric flasks respectively. Add 7 ml of hydrochloric acid (2.5) to each flask. Perform color development according to 5.4.6. Take the reagent blank (no phosphorus standard solution is added in this article) as reference and measure its absorbance at a wavelength of 800 nm on a spectrophotometer. Draw a curve with phosphorus content as the horizontal axis and absorbance as the vertical axis. 6 Calculation of analysis results
Calculate the percentage of phosphorus according to the following formula:
In the formula; m. Phosphorus content found from the working curve, g, o-
Total volume of test solution, ml
Volume of test solution, ml;
mo---sample volume, g.
Allowance difference
GB5195.6-85
The difference in analysis results between laboratories should not be greater than the allowable difference listed in Table 3. Table 3
0.0020~0.0050
0.0050 ~0.0100
0.0010~0.030
0.030~0.050
>0.050～0.100
0.10 ~0.30
0.30~0.50
Additional remarks:
This standard is proposed by China Nonferrous Metals Industry Corporation. This standard is drafted by Zhejiang Yingshi Mining Company. This standard is drafted by Zhejiang Metallurgical Research Institute. The main drafters of this standard are Dong Lijuan and Wang Fengmei. Supplement
From the date of implementation of this standard, the former Ministry of Metallurgical Industry Standard YB322-65 "Chemical Analysis Method of Stone" will be invalid. 16.
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