This standard specifies the determination of phosphorus content by phosphomolybdenum blue photometry. This standard is applicable to the determination of phosphorus content in limestone and dolomite, and also to the determination of phosphorus content in metallurgical lime. Determination range: phosphorus content 0.001% to 0.20%. GB/T 3286.6-1998 Chemical analysis method for limestone and dolomite Determination of phosphorus content GB/T3286.6-1998 Standard download decompression password: www.bzxz.net

GB/T3286.6—1998
This standard revises GB/T3286.8—1988 "Chemical analysis method for limestone and dolomite - determination of phosphorus by molybdenum blue photometry". The determination method of phosphorus pentoxide in JISM8850:1994 "Chemical analysis method for limestone" is adopted in a non-equivalent manner. This revision of the standard clarifies in the "scope" that it is also applicable to the determination of phosphorus in metallurgical lime. The sample amount is adjusted in the analysis method. The color developing solution measures the absorbance at its maximum absorption wavelength of 825nm to increase the measurement sensitivity. The "allowable difference" adds the laboratory allowable difference.
GB/T3286 "Chemical Analysis Methods for Limestone and Dolomite" includes the following nine substandards: GB/T3286.1 Determination of calcium oxide content and magnesium oxide content; Determination of silicon dioxide content,
GB/T 3286.2
GB/T 3286.3
GB/T 3286.4
GB/T3286.5
GB/T 3286. 6
GB/T 3286.7
GB/T 3286.8
Determination of aluminum oxide content,
Determination of iron oxide content;
Determination of manganese oxide content;
Determination of phosphorus content;
Determination of sulfur content;
Determination of loss on ignition,
GB/T 3286.9 Determination of carbon dioxide content. This standard replaces GB/T3286.8-1988 from the date of implementation. This standard was proposed by the former Ministry of Metallurgical Industry of the People's Republic of China. This standard is under the jurisdiction of the Information Standards Institute of the former Ministry of Metallurgical Industry, and this standard was drafted by Wuhan Iron and Steel (Group) Corporation. The drafting units of this standard are: Wuhan Iron and Steel (Group) Corporation Technology Center, Central South Institute of Metallurgical Geology. The main drafters of this standard are: Cao Hongyan, Shuai Xuren, Liu Jixian, Liang Lin, Chen Zibin. This standard was first issued in July 1982 and revised for the first time in September 1988. 66
1 Scope
National Standard of the People's Republic of China
Methods for chemical analysis oflimestone and dolomite-
The determination of phosphorus content
This standard specifies the determination of phosphorus content by phosphomolybdenum blue photometry. GB/T 3286. 6--1998
Replaces GB/T 3286. 8--1988
This standard applies to the determination of phosphorus in limestone and dolomite, and also applies to the determination of phosphorus in metallurgical lime. Determination model: phosphorus content 0. 001% ~ 0. 20%.
2 Referenced standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard is published, the versions shown are valid. All standards will be revised, and the parties using this standard should explore the possibility of using the latest version of the following standards. GB/T2007.2--1987 General rules for sampling and sample preparation of bulk mineral products Manual sample preparation method 3 Summary of the method
The sample is burned at high temperature, decomposed with hydrochloric acid, and fuming with perchloric acid. In a hydrochloric acid medium of about 0.5 mal/L, use hydroxylamine hydrochloride and ascorbic acid as reducing agents to reduce the generated phosphomolybdic heteropoly acid to phosphomolybdic blue, and measure the absorbance at a wavelength of 825 nm on a spectrophotometer. 4 Reagents
4.1 Hydrochloric acid (p1.19 g/mL).
4.2 Hydrochloric acid (1+4).
4.3 Perfluoric acid (p1.67 g/mL).
4.4 Hydrogen peroxide (p1.49 g/mL).
4.5 Hydroxylamine hydrochloride solution (40 g/L).
4.6 Ascorbic acid solution (10 g/L.).
4.7 Sodium citrate solution (15 g/L).
4.8 Ammonium hydroxide solution (15 g/L), filter before use if necessary. 4.9 Phosphorus standard solution
4.9.1 Weigh 0.4394 g of potassium dihydrogen phosphate (not less than 99.9%) that has been dried at 105°C for 2 h and cooled to room temperature into a 200 mL beaker, add 50 mL of water to dissolve, transfer to a 1 000 mL volumetric flask, dilute to the mark with water, and mix. 1.00 mL of this solution contains 100 grams of phosphorus.
Pipette 50.00 mL of phosphorus standard solution (4.9.1) into a 500 mL volumetric flask, dilute to the mark with water, and mix. 4.9.2www.bzxz.net
Approved by the State Administration of Quality and Technical Supervision on December 7, 1998 and implemented on July 1, 1999
1. 00 mL of this solution contains 10. 0 μg phosphorus.
GB/T 3286.6—1998
4.9.3 Transfer 10.00 mL of phosphorus standard solution (4.9.1) to a 500 mL volumetric flask, dilute to the mark with water, and mix well. 1. 00 mL of this solution contains 2. 0 μg phosphorus.
5 Instruments
In the analysis, only common laboratory instruments and equipment are used. 6 Sample preparation
Prepare the sample according to GB/T2007.2.
6.1 The sample should be processed to a particle size of less than 0.125 mm. 6.2 Before analysis, the limestone and dolomite samples should be dried at 105-110℃ for 2h and placed in a desiccator to cool to room temperature. 6.3 The preparation of metallurgical lime samples should be carried out quickly. After preparation, the samples should be immediately placed in ground-mouth bottles or plastic bags and sealed, and stored in a desiccator. The samples should not be dried before analysis.
7 Analysis steps
7. 1 Sample quantity
According to the phosphorus content in the sample, weigh the sample according to Table 1, accurate to 0.0001g. For metallurgical lime samples, the sample should be weighed quickly. Table 1
Phosphorus content, %
0.001~0.01
>0. 01～ 0, 05
>0. 05～0. 20
7.2 Blank test
Carry out a blank test with the sample.
7.3 Sample decomposition and test solution preparation
Sample amount, g
Test solution amount, mL
Working curve phosphorus content range, zone
2～20
10～~50
7.3.1 Place the sample (7.1) in a smooth porcelain, put it in a high-temperature furnace with a furnace temperature below 300℃, gradually heat it to 950~1000℃, and keep it for 30min. Take out the crucible and cool it. Carefully transfer the burned sample to a 150ml beaker and moisten it with water. 7.3.2 Add 10mL hydrochloric acid (4.1) and 5mL perchloric acid (4.3), heat to decompose, heat to evaporate until white perfluoric acid smoke appears, continue to evaporate until the volume of the solution is about 1mL, and cool. When the sample contains arsenic, after adding hydrochloric acid (4.1), add 1 ml of hydrobromic acid (4.4), then add perchloric acid (4.3), and heat to evaporate.
Note: The heated gastric smoke cannot be evaporated to dryness to avoid the formation of calcium phosphate precipitation. 7.3.3 Add 20 mL of water and heat to dissolve the salts. Filter the test solution into a 100 mL volumetric flask with medium-speed filter paper, wash the beaker and filter paper with hot water 4 to 5 times each, dilute with water to the scale, and mix well. 7.3.4 According to the phosphorus content in the sample, take the test solution according to Table 1 and put it into a 50 mL volumetric flask. 7.4 Determination
7.4.1 Add water to 20 mL, add 10 mL of hydrochloric acid (4.2), 4 mL of hydroxylamine hydrochloride solution (4.5), and 4 mL of ascorbic acid solution (4.6) in turn, and mix. Add 5 mL of sodium citrate solution (4.7) and mix well. Add 5mL of ammonium molybdate solution (4.8), mix well, and heat in a boiling water bath for 5 min. Cool to room temperature with running water, dilute to scale with water, and mix. 7.4.2 Use the blank test solution as a reference, select appropriate absorption III, measure the absorbance of the color solution at a wavelength of 825nm on a spectrophotometer, and find the corresponding phosphorus content on the working curve. 7.5 Working curve drawing
According to the phosphorus content of the sample, take different amounts of phosphorus standard solution (4.9.2 or 4.9.3) according to Table 1 and put them into a group of 50mL volumetric flasks. The following 68
GB/T 3286. 6
—1998
According to 7.4.1 Operation. Take the reagent blank solution as reference and measure the absorbance at a wavelength of 825nm on the spectrophotometer. Draw a working curve with the phosphorus content as the horizontal axis and the absorbance as the vertical axis.
8 Description of the analysis results
Calculate the mass percentage of phosphorus according to the following formula:
P(%) =
Wherein, V—total volume of test solution, mL;
volume of aliquoted test solution, mL;
phosphorus content found from the working curve, g;
m—sample volume·g.
9 Allowable difference
The difference between two independent analysis results in the laboratory and the difference between the analysis results of two laboratories should not be greater than the corresponding allowable difference listed in Table 2. For metallurgical lime samples, no allowable difference requirements are made between laboratories. Table 2
0. 001~0. 005
>0. 005~～0.010
>0. 010~0. 050
>0. 050~0. 100
>0. 100 ~0. 200
Allowable difference within the laboratory
Allowable difference between laboratories
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