This standard specifies the determination of manganese oxide content by periodate oxidation photometry. This standard is applicable to the determination of manganese oxide content (measured as MnO) in limestone and dolomite, and also to the determination of manganese oxide content in metallurgical lime. Determination range: manganese oxide content greater than 0.005%. GB/T 3286.5-1998 Chemical analysis method for limestone and dolomite Determination of manganese oxide content GB/T3286.5-1998 Standard download decompression password: www.bzxz.net

GB/T3286.5-1998
This standard amends GB/T3286.7-1982 "Chemical analysis method of limestone and dolomite - determination of manganese by periodate oxidation photometry".
This revision of the standard specifies in the "Model Diagram" that it is also applicable to the determination of manganese oxide in metallurgical lime. The specific operations such as the degree of sample decomposition and the heating method of the color development solution have been modified in the analysis method. The "Allowable Difference" adds the laboratory allowable difference. GB/T3286 "Chemical analysis methods for limestone and dolomite" includes the following nine substandards: GB/T 3286.1
GB/T 3286.2
Determination of calcium oxide content and magnesium oxide content;
Determination of silicon dioxide content,
GB/T3286.3 Determination of aluminum oxide content;
GB/T 3286.4
GB/T 3286.5
GB/T 3286. 6
GB/T 3286. 7
GB/T 3286.8
GB/T 3286, 9
Determination of iron oxide content;
Determination of manganese oxide content;
Determination of phosphorus content;
Determination of sulfur content;
Determination of loss on ignition;
Determination of carbon dioxide content.
This standard replaces GB/T3286.7--1982 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 Research Institute of the former Ministry of Metallurgical Industry. This standard was drafted by Wuhan Iron and Steel (Group) Corporation. Drafting units of this standard: Wuhan Iron and Steel (Group) Corporation Technology Center, Shanghai First Iron and Steel (Group) Co., Ltd. The main drafters of this standard: Cao Hongyan, Hong Zhiyong, Liu Jixian, Chen Zibin. This standard was first issued in July 1982.
1 Scope
National Standard of the People's Republic of China
Methods for chemical analysis oflimestone and dolomite--
The determination of. manganese oxide contentThis standard specifies the determination of manganese oxide content by periodate oxidation photometry. GB/T3286.5-1998
Replaces GB/T 3286.7-1982
This standard is applicable to the determination of manganese oxide content (measured in MnO) in limestone and dolomite, and also to the determination of manganese oxide content in metallurgical lime. Determination range: manganese oxide content greater than 0.005%. 2 Referenced standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard was published, the versions shown were valid. All standards are subject to revision. 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 Method Summary
The sample is burned at high temperature and decomposed with hydrochloric acid and perchloric acid. In phosphoric acid medium, divalent manganese is oxidized to permanganic acid with periodate under heating conditions, and the absorbance is measured at a wavelength of 525nm on a spectrophotometer. 4 Reagents
4.1 Hydrochloric acid (1+1).
4.2 Perfluoric acid (p 1. 67 g/mL).
4.3 Phosphoric acid (1+1).
4.4 Sodium (potassium) periodate solution (20g/L): Weigh 10g sodium (potassium) periodate in a beaker, add 300mL water, add 20mL nitric acid (1+1), dissolve in warm water, and dilute to 500mL with water. 4.5 Sodium nitrite solution (10 mg/L).
4.6 Water without reducing substances: Add 5 mL nitric acid (1+1) and 5 mL sodium (potassium) periodate solution (4.4) to every 1000 mL of analytical water, heat and boil for several minutes, cool and set aside. 4.7 Manganese oxide standard solution
4.7.1 Weigh 0.7745 g of metallic manganese (not less than 99.9%) into a 250 mL beaker, add 20 mL nitric acid (1+1), heat and dissolve, drive out all nitrogen oxides, and cool. Transfer the solution into a 1000 mL volumetric flask, dilute to the mark with water, and mix. This solution contains 1.00 mg manganese oxide in 1.00 mL.
4.7.2 Transfer 50.00 mL of manganese oxide standard solution (4.7.1) into a 500 mL volumetric flask, dilute to the mark with water, and mix. This solution was approved by the State Administration of Quality and Technical Supervision on December 7, 1998 and implemented on July 1, 1999.
1.00mL contains 100μg manganese oxide.
GB/T 3286.5—1998
Note: Metallic manganese should be treated with bowl acid (5+95) in advance to dissolve the surface oxide, washed with water, and then washed with anhydrous ethanol or ether for 3~4 times, and used after natural drying.
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 0.125mm6.2 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 are immediately placed in ground-mouth bottles or plastic bags and sealed, and stored in a desiccator: the samples are not dried before analysis.
7 Analysis steps
7. 1 Sample quantity
Weigh the sample according to Table 1, accurate to 0.0001g. For metallurgical lime samples, the sample should be weighed quickly. Table 1
Content of manganese oxide, %
>0. 10～0. 40
7.2 Blank test
Carry out a blank test with the sample.
7.3 Sample decomposition and test solution preparation
Sample quantity g
7.3.1 Place the sample (7.1) in a smooth porcelain crucible, put it in a high-temperature furnace with a furnace temperature below 300℃, gradually raise the temperature to 950~1000℃, and keep it for 30min. Remove and cool. Carefully transfer the sample after burning to a 100 ml beaker and moisten with water. Note: The burning residue after the determination of burning loss can also be used as the sample for this method. Carefully transfer it to a 100 ml beaker and moisten with water. 7.3.2 Add 15 ml hydrochloric acid (4.1) and 5 ml perchloric acid (4.2), heat to decompose, heat to evaporate until white perchloric acid smoke appears, and continue to evaporate until the volume of the solution is about 1 to 2 ml, and cool.
7.3.3 Add 10 ml of water and heat to dissolve the salts. Filter into a 150 ml conical flask with medium-speed filter paper, wash the beaker and filter paper with hot water 4 to 5 times each, and control the volume of the solution to be 40 to 50 ml. 7.3.4 Add 20 ml of phosphoric acid (4.3) and 10 ml of sodium (potassium) periodate solution (4.4), heat to boiling at low temperature, and keep it at a slight boiling state for 3 to 4 minutes, and cool. Transfer the solution to a 100mL volumetric flask, dilute to the mark with water (4.6) that does not contain reducing substances, and mix. 7.4 Determination
Pour the color-developing solution into an appropriate amount of absorbent medium, and pre-place 1 to 2 drops of sodium nitrite solution (4.5) in another absorbent medium. Pour the remaining color-developing solution into the sample solution as a reference solution, and measure the absorbance of the color-developing solution at a wavelength of 530nm on a spectrophotometer. Subtract the absorbance of the blank test solution from the absorbance of the sample solution, and find the corresponding amount of manganese oxide on the working curve. 7.5 Plotting the working curve
Take 0, 0.50, 2.00, 4.00, 6.00, 8.00, and 10.00mL of the manganese oxide standard solution (4.7.2), place them in several 150mL conical flasks, add 2mL of perfluoric acid (4.2), and dilute to 40 to 50mL with water. Follow the steps in 7.3.4. Use the reagent blank as a reference and measure the absorbance at a wavelength of 525nm on the spectrophotometer. Draw a working curve with the amount of manganese oxide as the horizontal axis and the absorbance as the vertical axis. 64
8 Description of the analysis results
Calculate the mass percentage of manganese oxide according to the following formula: GB/T 3286.5
—1998bzxz.net
ml×100
MnO(%) -
Where: ml——the amount of manganese oxide found from the working curve, g; sample amount·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
Amount of manganese oxide
0. 005 ~0.010
>0. 010~0. 050
>0.050~0.100
>0.10~0. 40
Permissible difference within the laboratory
Permissible difference between laboratories
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