HG 2958.3-1988 Determination of sulfate content in celestite ore - Barium sulfate gravimetric method

HG 2958.3-1988 Determination of sulfate content in celestite ore Barium sulfate gravimetric method HG2958.3-1988 standard download decompression password: www.bzxz.net

Chemical Industry Standard of the People's Republic of China
Celestite ores-Determination of sulphate content-Bariumsuiphate gravimetric method
1 Subject content and scope of application
This standard specifies the determination of sulfate content in celestite ores by the barium sulfate gravimetric method. This standard applies to celestite ores with a sulfur trioxide content greater than 5%. 2 Reference standards
GB9018.1 Determination of strontium and calcium content in celestite ore EDTA volumetric method 3 Method summary
UDC549.761.3bzxz.net
HG/T2958.3-1988(1997)
Replaces GB9018.3-88
The sample is melted with sodium carbonate and sodium hydroxide to convert sulfate into soluble sulfate, which is precipitated with barium chloride in an acidic medium, filtered, burned and weighed. The sulfur trioxide content is calculated from the mass of barium sulfate. 4 Reagents and solutions
4.1 Hydrochloric acid (GB622-77): 1+1 solution; 4.2 Hydrochloric acid: 1+200 solution;
Disodium ethylenediaminetetraacetate (EDTA) (GB1401-78): 5% solution; 4.3
Ethanol (GB679-80) (95%);
4.5 Methyl red (HG3-958-76): 0.2% ethanol solution; 4.6 Barium chloride (GB652-78): 10% solution (filter before use); 4.7 Silver nitrate (GB670-77): 1% solution. 5 Analysis steps
Add 5 ml of EDTA solution (4.3) and 2 drops of methyl red indicator (4.5) to the solution A prepared in 5.1 of GB901S.1, cover the surface blood (leave a gap), carefully adjust the solution to red with hydrochloric acid (4.1), add 5 ml in excess, heat and boil for 3-4 minutes, drive out all the carbon dioxide, remove, rinse the surface dish and beaker wall with water, and dilute to 300 ml. Add 15-20 ml of hot chlorination solution (4.6) under constant stirring, keep warm at 70-90°C for 2 hours, remove, and leave for more than 3 hours. Filter with dense filter paper, wash the precipitate with warm hydrochloric acid (4.2) 2-3 times, and then wash with warm water until there is no chloride ion [check with silver nitrate solution (4.7)]. Transfer the precipitate and filter paper into a constant weight porcelain crucible, carefully heat and incinerate the filter paper, place the porcelain in a muffle furnace, burn at 800℃ for 1h, take it out and cool it in a dryer, weigh it, and burn it to constant weight. At the same time, do a blank test
Previous: If the sample contains bacteria, burn it at 800℃ for 30min in advance. Prepare solution A according to 5.1 of GB9018.1. Approved by the Ministry of Chemical Industry of the People's Republic of China on March 21, 1988·52·
Implementation on December 1, 1988
Calculation of analysis results
4HG/T2958.3-1988（1997）
The percentage content of sulfur trioxide (X) is calculated according to the following formula: X
In the formula: ml-
【(m-m2)-(mm)】×0.3430
-The mass of the precipitate after calcination and the porcelain crucible, g; m
-The mass of the porcelain crucible, g;
m3-The mass of the precipitate after calcination and the porcelain crucible of the blank test, g; -The mass of the porcelain tower of the blank test, g;
m-The mass of the sample, g;
0.3430-The coefficient for converting sulfuric acid to sulfur trioxide. Allowable difference
The difference of the test results in the same laboratory should be less than the value shown in the table below. Sulfur trioxide content (SO)
5.0010.00
>10.00~30.00
Additional instructions:
This standard is under the jurisdiction of the Chemical Industry and Mining Design and Research Institute of the Ministry of Chemical Industry. This standard was drafted by the Chemical Industry and Mining Design and Research Institute of the Ministry of Chemical Industry. The main drafters of this standard are Xu Xiulan and Gu Lihua. Allowable difference
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