HG 2957.9-1984 Determination of silicon content of alum ore by gravimetric method

HG 2957.9-1984 Determination of silicon content of alum stone ore Gravimetric method HG2957.9-1984 standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Determination of silicon content in alunite ore
Gravimetric method
Alunite ores---Determination of silicon contentGravimetric method
Scope of application
UDC 549.762:543.
.21:546.28
GB 4681.9-84
Provision: Ha
This standard specifies the determination of more than 10% silicon dioxide content in alunite ore by the ignition difference weight loss method. 2Related standards
GB4581.1-84 "General rules for analysis of alunite ores". GB4581.2-84 "Methods for sampling and preparation of corundum ore analysis samples". 3 Method Summary
The sample is decomposed by perchloric acid, and the slag is treated with hydrofluoric acid and sulfuric acid. Silicon escapes in the form of silicon tetrafluoride. According to the loss on ignition, the content of silicon dioxide is calculated. bzxZ.net
4 Reagents and solutions
4.1 Perchloric acid (GB 623-77) (70%). 4.2 Hydrofluoric acid (GB 620-77) (40%). 4.3 Sulfuric acid (GB 625-77) (specific gravity 1.84): 1 +15
Determination procedure
Weigh 0.5 g of sample and add it to 100 ml of dry beaker. Add 10 ml of perchloric acid (4.1) along the wall of the beaker. Shake the beaker gently to prevent the sample from sticking to the bottom. Cover the surface, heat on an electric heating plate until boiling, and keep boiling for 1 hour. Remove and cool, blow the surface blood and the wall of the beaker with hot water, and add a small amount of hot water to heat and dissolve the salts. Filter with dense quantitative filter paper, wash the residue 3 times with hot water, transfer all the residue to the funnel, and wash the residue more than 10 times. Put the residue together with the filter paper in a crucible, dry for ten days, ashed, place in a muffle furnace and burn at 850℃ for 1 hour, take out, cool and weigh, and burn to constant weight. Wet the residue with a small amount of water, add 6 drops of sulfuric acid solution (4.3), add 10 ml of hydrofluoric acid (4.2), heat on a hot plate at low temperature to evaporate until white smoke of boric acid is emitted, take it off and cool, add 3 ml of hydrofluoric acid (4.2), and heat on a hot plate until white smoke of sulfuric acid is emitted. Place it in a muffle furnace, burn at 850℃ for 1 hour, take it out, cool and weigh, and burn to constant weight. 6. Presentation and calculation of results
The percentage content of silicon dioxide (SiO2) (X,) is calculated according to the following formula: Xa-
Wherein: G1——weight of residue and platinum crucible before hydrofluoric acid treatment, g, Gz——weight of residue and crucible after hydrofluoric acid treatment, g; W——weight of sample, g.
Promulgated by the State Bureau of Standards on July 20, 1984
Implemented on June 1, 1985
Tolerance
Additional notes:
Silicon dioxide content,
.40.00
GB 4581.9-84
Tolerance (absolute value), %
This standard is proposed by the Ministry of Chemical Industry of the People's Republic of China and is funded by the Chemical Industry Mining Design and Research Institute of the Ministry of Chemical Industry. This standard is drafted by the Chemical Industry Mining Design and Research Institute of the Ministry of Chemical Industry. The main drafter of this standard is Cheng Maomei.
From the implementation of this standard, the original chemical industry standard HG1-353-66 "Uniform analysis method for alum" will be invalid.
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