CS262318B1 - Process for the determination of total sulphur in coal - Google Patents

Abstract

The solution concerns the determination of all sulfur in coal by radionuclide X-ray fluorescence analysis. The solution is to that the coal sample is first irradiated by radiation radionuclide 545Fe and proportional detector the characteristic radiation is measured sulfur, calcium and backscattered radiation SSpe, whereupon the sample is irradiated with a radionuclide 238pu and the characteristic radiation is measured iron and scattered radiation 238p and five the values obtained in the characteristic lumps radiation of sulfur, calcium, and iron 55pe a 238pu is correlated.

Description

The invention relates to a method for the rapid determination of the total sulfur content of coal by the radionuclide X-ray fluorescence analysis method, eliminating the effect of calcium, iron and ash on the results of the determination of all sulfur.

Nowadays there are classical methods of chemical analysis. Their advantage is accuracy; however, they are time-consuming and expensive. Of the physical methods for determining all sulfur, it is primarily the method of X-ray fluorescence analysis.

Currently, semiconductor detection methods can be used in the RFA method to quickly determine all sulfur in coal; however, it cannot be used according to the invention directly in operating conditions because it requires cooling of the detector with liquid nitrogen and at the same time this detection method can be applied only to stationary devices, not to portable devices in situ. The scinfillation detection method cannot be used due to the very low energy K _and sulfur line. The current proportional detection method in the RFA method is suitable for determining such low energy K _and sulfur lines, but does not take into account the calcium or ash content present in the determination of sulfur in coal, which sometimes results in a negative or distorted RFA result. Since calcium, iron and ash are always present in the coal samples, especially in brown coal, these three components, mainly calcium, fundamentally influence the determination of all sulfur in the coal, thus affecting the applicability of the method.

All prior-art X-ray fluorescence methods, including currently used analyzers, do not consider this effect of interfering accompanying impurities for the direct determination of all sulfur in coal samples under operating conditions, including the methods and equipment used in MS. author's certificates No. 240 870 and No. 235 723; 232 406 and according to DE-OS No 2 607 968, which does not consider the elimination of the influence of calcium and ash in coal

The existing drawbacks are eliminated by the method according to the invention, characterized in that the coal sample is first irradiated with radionuclide radiation _and the characteristic radiation of sulfur, calcium and backscattered Fe is measured by means of a proportional detector. iron and diffused 238 Pu radiation and the five values obtained in the peaks of characteristic radiation of sulfur, calcium,

238 iron and in the scattered radiation of Fe and Pu radiation are correlated. The advantage of the method according to the invention is the speed and reliability of the determination of all sulfur. According to the method according to the invention, the measured data, expressed in the pulse frequencies for sulfur, calcium, iron and scattered radiation of both emitters, are evaluated so that the presence of the neglected influence of calcium, iron and ash in the measured sample. It is also possible to determine the iron content with the influence of calcium and in turn to determine the ash content with the influence of iron and calcium. Compared to the chemical analysis data, the regression dependence in the determination of all sulfur can be processed into a computer program and by microprocessor technology to express the content of all sulfur in percent after eliminating the abovementioned disturbances of calcium, iron and ash, eg directly on the analyzer display.

The effects of the invention can be seen from the results table of the analysis of several coal samples carried out by the classical chemical analysis and method according to the invention.

Example

By the method according to the invention, the content of all sulfur in coal was compared with the results of chemical analysis of six brown coal samples from the North Bohemian brown coal district:

Sample number Analysis according to the invention Chemical analysis

[c]% i, 31

1.97

1.17

2.00

Continuation table

Sample number

Analysis according to the invention [c] S%

Chemical analysis [c] S%

4.66 4.54 1.69 1.80 1.54 1.34 1.09 0.91

The comparison shows that for concentrations of all sulfur in coal above 2% the relative percentage error will not exceed - 10% by weight and for concentrations of up to 2% of all sulfur in coal the determination error will not exceed - 0.20% by the absolute method of the invention. The assay according to the invention is primarily intended for operating conditions.

Claims (1)

Method for determining the total sulfur content of coal by a radionuclide X-ray fluorescence analysis method, characterized in that the coal sample is first irradiated with Fe radiation and a proportional detector to measure the characteristic sulfur, calcium and backscattered radiation 55pe, then irradiating the sample with ³³ ®Pu and the characteristic is measured 238 of the iron radiation and the scattered radiation of Pu and the five values obtained in the peaks characteristic of sulfur, calcium, iron and the scattered radiation of Fe and Pu radiation are correlated.