This standard specifies the determination of combined water content by gravimetric method. This standard is applicable to the determination of combined water content in manganese ore. Determination range: 1.00% to 8.00%. GB/T 14949.12-1994 Chemical analysis method for manganese ore Determination of combined water content GB/T14949.12-1994 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Chemical analysis method of manganese ore
Determination of combined water content
Manganese ore-Determination of combined water contentThis standard is equivalent to the international standard 1SO549-1981 "Manganese ore 1 Subject content and scope of application
This standard specifies the determination of combined water content by weight method. This standard applies to the determination of combined water content in manganese ore. Determination range: 1.00%~8.00%.
2 Summary of method
GB/T 14949.12-94
Determination of combined water content
Gravimetric method".
Heat the sample in a dry fluorine gas flow to separate the combined water, and collect it in an absorption tube filled with magnesium perchlorate and determine it by weight method. 3 Reagents
3.1 Anhydrous magnesium perchlorate: Bake at 120~～125℃ for 1h3.2 Lead oxide.
3.3 Lead chromate.
3.4 ​​Lead chromate-lead oxide mixture (2+1): Weigh 20g lead chromate (3.3) and 10g lead oxide (3.2) and place them in a 150mL beaker or porcelain crucible, add a small amount of acid asbestos and a small amount of water and stir well to make small balls with a diameter of about 0.3-0.5cm, put them in a porcelain crucible and heat them in a high-temperature furnace at 500-600℃ for 1h, cool them in a desiccator and set them aside. 3.5 Floating: Particles with a diameter of about 0.3-0.5cm. are heated in a high-temperature furnace at 800C for 30min, then placed in a desiccator and cooled for use. 3.6 Sulfuric acid (pl.84g/mL)
4 Instruments and devices
4.1 Silver spiral.
4.2 Porcelain: Pre-burn at 1000℃ for 1h and place in a desiccator. On the day of use, The required porcelain boat that has been pre-burned at 1000°C is covered in a tubular electric furnace (c), and fluorine gas is passed through it at 850-900°C for 10-15 minutes, then taken out and cooled slightly, and placed in a lower desiccator for later use. 4.3 High-temperature tubular electric furnace with a single tube and two silicon carbon rods. 4.4 Low-temperature tubular electric furnace with an outer diameter of 70mm, a length of 140mm, and 500W. 4.5 Fluorine gas.
4.6 Ten drying tower
filled with magnesium perchlorate (3.1).
4.7 Sulfuric acid (3.6) is contained in a gas washing bottle.
4.8 The U-shaped glass absorption tube with a mushroom mouth and a branch tube has an inner diameter of 10mm and a length of 100mm, and is filled with magnesium perferrate (the total mass of each tube does not exceed 40g). It is saturated with carbon dioxide and left overnight. 4.9 The porcelain tube is 500-600mm long and has an inner diameter of 18-20mm. The conical end of the tube is 50mm long and 35mm in inner diameter. A silver spiral (4.1) is placed at a distance from the end of the conical end. The mixture of 15g lead chromate-lead oxide (3.4) and 5% pumice (3.5) or 25-30g lead chromate.lead oxide (3.4) with a length of 7-9cm is filled. The two ends are blocked with silver sheets (with holes) or silver wires. Lead chromate-lead oxide floats are better than silver spirals in removing interference. However, care should be taken when filling it into the porcelain tube to avoid powder that is not carried into the absorption tube by the carrier gas and increases the mass of the absorption tube.
4.10 Schematic diagram of the analysis device
A gas washing bottle ( 4.7); H drying tower (4.6); C tubular electric furnace (4.3); D porcelain tube (4,9): E- tubular electric furnace (4.4); F, G-- absorption tube (4.8); H washing bottle (4.7) Note: The pointed conical end of the porcelain tube (D) is connected to the absorption tube with a silicone rubber tube. The distance between the absorption tube (F) and the tubular electric furnace (E) should be as short as possible. 5 Sample
The sample should pass through a 0.100mm sieve and be air-dried under experimental conditions. 6 Analysis steps
6.1 Sample quantity
Weigh the sample according to Table 1, accurate to 0.0001g. Table 1
Combined water content, %
Sample crab, g
0.40~0.35
During the determination, weigh the sample to determine the percentage of moisture in the test chamber (A). When calculating the result of combined water content, the percentage of wet water (A) should be subtracted and multiplied by the conversion factor (K), which is the mass percentage of combined water content measured in the completely dry sample. Conversion factor K
6.2 Constant weight absorption tube
100 — A
6.2.1 Before the measurement, check the sealing of the analysis device at a rate of 2 to 3 bubbles/5. After checking and confirming that it is leak-proof, the following operation steps can be carried out.
6.2.2 Connect the tubular electric furnace (C) and heat to 800~90°C. At the same time, connect the electric furnace (E) and heat to 200~250)℃ and keep it for 30~40min. Then connect the absorption tube to the device, unscrew the piston on the absorption tube, continue to pass argon for 1h, close the piston, and put the absorption tube into the desiccant-free dryer in the balance room to cool for 35min. Unscrew the piston of the absorption tube and close it immediately to balance the pressure in the tube with the atmospheric pressure. Then weigh and record the mass of the absorption tubes (F) and (G) (the whole operation must be done carefully. Before weighing the absorption tube, the surface of the absorption tube must be wiped clean with filter paper or soft cloth). Repeat the above analysis steps (change the ventilation time to 30~40min). The total mass difference of the two absorption tubes weighed twice is less than or equal to 1mg, which means constant weight has been achieved (under normal circumstances, the weight of the absorption tube should increase or remain unchanged after each ventilation. If it decreases, check the sealing of the absorption tube or repeat the operation). 6.3 Blank test
Carry out a blank test with the sample.
Connect the absorption tube of known mass to the porcelain tube (1) that has been cooled to about 400°C, quickly push the porcelain boat containing the sample into the middle of the porcelain tube (D) passing through the electric furnace (C) with a long steel hook, immediately plug it, unscrew the piston of the absorption tube, let in air at a rate of 2 bubbles/s, turn on the electric furnace (E), heat it to 280-300°C, then turn on the electric furnace (C) and gradually raise the temperature to 850-900°C, then keep it for 30-60 minutes depending on the water content of the sample (heat until no water droplets are observed in the branch of the absorption tube connected to the combustion tube. Heat for another 10 minutes). Turn off the electric furnace (C), continue heating the electric furnace (E) for 5-10 minutes and then turn it off. Continue to ventilate until the porcelain tube (D) cools to about 400°C. Close the piston of the absorption tube, remove the absorption tubes (F) and (G), and place them in a desiccant-free desiccator in the balance room. Cool for 35 minutes, unscrew the piston of the absorption tube and immediately close it to balance the pressure in the tube with the atmospheric pressure, then weigh and record the mass of the absorption tubes (F) and (G). If there is foreign matter in the branch of the absorption tube, wipe it clean with debonded cotton and weigh it. On the day of the measurement, the absorption tube can continue to be used. The mass of the absorption tube measured in the previous measurement is the mass of the empty absorption tube for the next measurement. The measurement on the second day needs to be repeated at constant weight. 7 Calculation of analysis results
Calculate the mass percentage of combined water according to the following formula: H,O+ (%) = [(m:2m -m2 × 100 - A]Km
Where: m—mass of the sample;
m.—combined water mass base measured in the air test, g; m—mass of the absorption tube before absorbing water, g; m2—mass of the absorption tube after absorbing water, g; A—mass percentage of wet water measured;
: conversion coefficient of mass percentage of combined water in completely dry sample. 8 Precision
The precision listed in this standard is the repeatability and reproducibility R obtained by eight laboratories from 1990 to 1991 on four uniform samples with the same uniform distribution within the determination range of this method, according to the analysis steps of this method, and after jointly conducting tests, summarizing the data and conducting statistical analysis in accordance with the national standard GB6379, see Table 2. The original data are shown in Appendix A. Table 2
Level, % (m/m)
Repeatability,
Igr - --1. 114 1 --0. 603 11gmReproducibilityR
R-=0. 076 13-+ 0. 026 01m
Repeatability is the maximum difference between two independent test results at the 95% probability level, when the method is used under normal and correct operation, by the same operator, in the same laboratory, using the same instrument, and in a short period of time, for the same sample. Reproducibility is the maximum difference between two independent test results at the 95% probability level, when the method is used under normal and correct operation, by two operators in different laboratories.The maximum difference between two independent test results at the 95% probability level for each single test result of the same sample. If the difference between two independent test results exceeds the corresponding repeatability and reproducibility data, the two results are considered suspicious3
Laboratory
Additional notes:
GB/T14949.12---94
Appendix AwwW.bzxz.Net
Original data of precision test
(Supplement)
This standard is proposed by the Ministry of Metallurgical Industry of the People's Republic of China. H,O-3
This standard was drafted by the Mineral Geology Research Institute of China Nonferrous Metals Industry Corporation and the Changsha Mining and Metallurgical Research Institute of the Ministry of Metallurgical Industry. This standard was drafted by the Mineral Geology Research Institute of China Nonferrous Metals Industry Corporation. The main drafters of this standard are Wu Shuangfeng, Zhang Jinian and Shu Baicong. 36.1
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