This standard specifies the gravimetric method for determining the content of carbon dioxide. This standard applies to the determination of carbon dioxide content in limestone products for chemical use, with a determination range of 0.5% to 5%. GB/T 15057.4-1994 Gravimetric method for determining the content of carbon dioxide in limestone for chemical use GB/T15057.4-1994 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Determination of iron and aluminium oxides content in limestone for chemical industry---Gravimetric method
Limestone for chemical industry-Determination of iron and aluminium oxides content---Gravimetric method1 Subject content and scope of application
This standard specifies the gravimetric method for the determination of trioxide content. GB/T 15057.4--94
This standard applies to the determination of trioxide content in limestone products for chemical industry, with a determination range of 0.5% to 5%. 2 Reference standards
GB6682 Specifications and test methods for water for analytical laboratories GB/T15057.3 Determination of hydrochloric acid insoluble matter in limestone for chemical industry-Gravimetric method 3 Method summary
The sample is decomposed with hydrochloric acid and filtered, the filtrate is boiled with nitric acid, methyl red is used as an indicator, and trioxide is precipitated by ammonia water, left for a while, filtered, the precipitate is dried, ashed, burned, and weighed. 4 Reagents and Solutions
The water used in this standard shall comply with the specifications of Grade III water in GB6682; the listed reagents, unless otherwise specified, are analytically pure reagents. 4.1 Nitric acid (GB626): 1+1 solution.
4.2 Ammonia water (GB631): 1+1 solution.
4.3 Silver nitrate (GB670): 10g/L solution. 4.4 Methyl red indicator (HG3958): 2g/L ethanol (GB679) solution. 5 Analysis steps
5.1 Use the filtrate obtained in 6.2 of GB/T15057.3, add 3~5 drops of nitric acid solution (4.1), heat and concentrate the filtrate to 200~250mL. Boil, add 2 drops of methyl red indicator solution (4.4), neutralize drop by drop with ammonia solution (4.2) until the filtrate turns yellow, and then add 1mL in excess. Boil, keep warm for a while, filter with rapid quantitative filter paper after the precipitate sinks, collect the filtrate in a 500mL volumetric flask, wash the precipitate with hot water until the filtrate is free of chloride ions. Test with silver nitrate solution (4.3). Keep the filtrate and use it to determine calcium oxide and magnesium oxide. 5.2 Put the precipitate and filter paper into a constant weight porcelain crucible, dry, ash, and place in a high temperature furnace to burn at 950±25℃ for 60min. Take out the crucible, cover the crucible immediately, cool it slightly, put it in a desiccator, cool to room temperature, and weigh it. Repeat the burning for 20min until constant weight is achieved.
Approved by the State Administration of Technical Supervision on May 5, 1994, 192
Implemented from February to January, 1995
6 Summary of analysis results
GB/T15057.4---94
The content of trichloride (R03) expressed as mass percentage (kg) is calculated as follows: m-m2 ×100Www.bzxZ.net
where m is the mass of trichloride and crucible after deducting blank, g, ma is the mass of empty crucible, g,
7 Allowable difference
The mass of sample, g.
The arithmetic mean of the parallel analysis results is taken as the final analysis result. The absolute difference of the parallel analysis results shall not be greater than the allowable difference listed in the following table.
Additional remarks:
Content of trichloride (R03)
This standard is proposed by the Ministry of Chemical Industry of the People's Republic of China. This standard is under the jurisdiction of the Chemical Industry Design and Research Institute of the Ministry of Chemical Industry. This standard was drafted by the Chemical Industry Design and Research Institute of the Ministry of Chemical Industry. The main drafter of this standard is Li Donghao.
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