Method for determining content of sulfite in wet desulphurization slurry

Abstract

The invention relates to a method for determining the content of sulfite in a wet desulphurization slurry. The method comprises the following determination steps: 1, adding 50ml of an acetic acid-sodium acetate buffer solution having a pH value of 4.0-5.7 and 10.00ml of a 0.1mol / L iodine standard solution to a stopper possessed measuring flask; 2, adding a tested sample filtrate until the iodine solution becomes flavescent or tannish, and carrying to a laboratory under a dark condition; 3, adding 1ml of a 1% starch solution to make the tested sample become blue; 4, titrating the sample solution with a 0.1mol / L sodium hyposulfite standard solution until the blue color disappears, and recording the consumption amount of the sodium hyposulfite standard solution; carrying out a blank experiment; and 6, calculating to obtain the content of sulfite. The method which allows the buffer solution to be added in the sampling process has the advantages of avoiding of the oxidation in the sampling process, prevention of the interference of components comprising S2O3<2-> and the like in the test process, increase of the interference resistance of the slurry in the sampling and testing process, and improvement of the accuracy and the reliability of the test result.

Description

technical field

[0001] The invention belongs to the technical field of industrial analysis and measurement methods, and relates to a method for determining the content of sulfite in wet desulfurization slurry. Background technique

[0002] The sulfite content is an important indicator to measure the oxidation status of the wet flue gas desulfurization system, and it is a must-test item for production and operation. The iodometric method is usually used to determine the content of sulfite. The basic principle is: in the presence of excess iodine standard solution, sulfite reacts with excess iodine, and the remaining iodine is titrated with sodium thiosulfate solution. The sulfite content was calculated indirectly from the amount of sodium thiosulfate consumed. Its main chemical reaction is: SO 3 2- +I 2 +H 2 O=SO 4 2- +2H + +2I - ①, 2Na 2 S 2 o 3 +I 2 = Na 2 SO 4 +2 NaI ②.

[0003] GB21508-2008 "Performance Test Method for Coal-fired Flue Gas Desulfurizatio...