阅读说明：本技术 一种粗硒中硒的定量分析方法 (Quantitative analysis method for selenium in crude selenium ) 是由 王津 熊晓燕 张胜 唐维学 于 2020-05-27 设计创作，主要内容包括：本发明所述的粗硒中硒的定量分析方法,包括S1.将粗硒和分散剂配比为：分散剂的质量比≤50％混合,压制成样片；S2.将多个含量不同且已知硒含量的粗硒制作成标准样片,使用能量色散X射线荧光光谱仪测定标准样片的硒元素的荧光强度值,绘制标准样片的硒含量与相应荧光强度值的对应关系标准曲线；S3.使用能量色散X射线荧光光谱仪测定已制备好的待测样品的样片的硒元素的荧光强度值,根据标准曲线上的荧光强度值,得到待测样品的硒含量。本发明样片制备方法独特,加入了具有分散性质的锂盐以实现样片的成型。该样片适合能量色散X射线荧光光谱法对粗硒中硒含量的定量检测。本发明检测时间短、效率高,操作简单,测量结果准确。(The quantitative analysis method of selenium in crude selenium comprises the following steps of S1, proportioning the crude selenium and a dispersing agent: mixing the dispersing agents with the mass ratio of less than or equal to 50 percent, and pressing into sample pieces; s2, manufacturing a plurality of crude selenium with different contents and known selenium content into standard sample wafers, measuring the fluorescence intensity value of selenium element of the standard sample wafers by using an energy dispersion X-ray fluorescence spectrometer, and drawing a corresponding relation standard curve of the selenium content of the standard sample wafers and the corresponding fluorescence intensity value; and S3, measuring the fluorescence intensity value of the selenium element of the prepared sample wafer of the sample to be measured by using an energy dispersion X-ray fluorescence spectrometer, and obtaining the selenium content of the sample to be measured according to the fluorescence intensity value on the standard curve. The preparation method of the sample wafer is unique, and the lithium salt with dispersion property is added to realize the molding of the sample wafer. The sample is suitable for quantitative detection of selenium content in crude selenium by energy dispersive X-ray fluorescence spectrometry. The invention has the advantages of short detection time, high efficiency, simple operation and accurate measurement result.)

1. A quantitative analysis method for selenium in crude selenium is characterized by comprising the following steps:

the method comprises the following steps:

s1, preparing a sample wafer of a sample to be detected: mixing the crude selenium and the dispersing agent, stirring uniformly, and pressing into a sample tablet; wherein the mass ratio of the dispersing agent to the sample is not more than 50%;

s2, preparing a standard sample and drawing a standard curve: manufacturing a plurality of crude selenium with different contents and known selenium content into sample wafers, measuring the fluorescence intensity value of selenium element of a standard sample wafer by using an energy dispersion X-ray fluorescence spectrometer, and drawing a standard curve of the mapping relation between the selenium content of a standard sample and the corresponding fluorescence intensity value;

s3, determining the selenium content of the sample to be detected: and measuring the selenium element fluorescence intensity value of the sample wafer of the sample to be measured by using an energy dispersion X-ray fluorescence spectrometer, and obtaining the selenium content of the sample to be measured according to the fluorescence intensity value on the standard curve.

2. The method of claim 1, wherein the method comprises: in the step S1, the dispersing agent is lithium salt.

3. The method of claim 2, wherein the method comprises: the lithium salt is lithium carbonate.

4. The method for quantitative analysis of selenium in crude selenium according to any one of claims 1 to 3, wherein: in the step S1, the granularity of the dispersing agent is not less than 200 meshes.

5. The method of claim 1, wherein the method comprises: in the step S1, the pressure of a pressing sample is 10-30 t, and the time for keeping the pressing sample is 10-30 s.

6. The method of claim 1, wherein the method comprises: the measuring spectral line selected in the step S3 is K_βA wire.

Technical Field

The invention relates to the technical field of chemical analysis methods, in particular to a quantitative analysis method for selenium in crude selenium.

Background

Generally, in the process of extracting gold and silver from copper electrolysis anode slime, byproducts with recovery value, such as crude selenium which can be used for preparing selenium oxide and refined selenium, are generated. The crude selenium process uses a sulfuric acid roasting method, copper electrolysis anode mud and concentrated sulfuric acid are mixed and then added into a rotary kiln for acidizing roasting, a certain temperature is controlled, copper in the copper electrolysis anode mud is converted into water-soluble copper sulfate, selenium is converted into selenium dioxide to enter an absorption tower, and then the selenium dioxide reacts with sulfur dioxide in furnace gas to obtain crude selenium, so that a sample contains a small amount of sulfuric acid. The main component of the crude selenium is selenium, and the content of the selenium is 70 to 98 percent. And the sample also contains impurity elements such as sulfur, copper, silver, arsenic and the like, and has certain viscosity due to the fact that the sample contains a small amount of sulfuric acid and moisture. If the crude selenium is used, the selenium content in the crude selenium needs to be accurately measured, which is important for the subsequent production process of chemical products such as selenium oxide, refined selenium and the like.

The determination of the selenium content in the crude selenium comprises common gravimetric methods and titration methods, such as YS/T1084.3-2018 part 3 of chemical analysis method of crude selenium: determination of selenium amount hydroxylamine hydrochloride reduction gravimetric method and sodium thiosulfate titration method. When the weight method and the titration method are used for detecting the selenium content, the method has the advantages of good reproducibility of the detection result and stable result. However, the accuracy of the measurements of these two methods is affected by other elements in the sample. Secondly, a large amount of acid and other reagents are needed for sample treatment, the analysis takes about 1 day, the requirement of rapid production detection cannot be met, the progress of the subsequent process is influenced, the energy consumption is high, and the used reagents pollute the environment.

In order to improve the detection efficiency, the prior art also adopts wavelength dispersion X-ray fluorescence spectrometry to detect the content of metal elements in the copper electrolysis anode mud, wherein the metal elements comprise selenium but are not used for detecting the selenium. For example, application No. 201510027996.X, the subject is a method for determining the content of metal elements in copper anode slime. Because the selenium content in the process of extracting gold and silver from copper electrolysis anode mud is below 15%, the technical scheme is not suitable for accurately detecting the selenium content in the crude selenium.

In conclusion, the existing detection method for the selenium content in the crude selenium has the defects of long detection time, high energy consumption and environmental pollution. The crude selenium sample contains sulfuric acid, and if a wavelength dispersive fluorescence (WD-XRF) method is adopted, the sample wafer generates corrosive gas under vacuum, so that the instrument is damaged. Therefore, a method which can rapidly and accurately perform quantitative analysis on selenium in crude selenium, and can reduce the damage of volatile corrosive gas in a sample to equipment and reduce environmental pollution is still lacking at present.

Disclosure of Invention

The invention aims to overcome the defects and shortcomings and provides a quantitative analysis method for selenium in crude selenium, which has the advantages of high detection efficiency, reduced corrosivity, long service life of instruments and equipment, high detection environment compatibility and simplicity in operation.

In order to achieve the purpose, the invention adopts the specific technical scheme that the method comprises the following steps:

s1, preparing a sample wafer: mixing the crude selenium and the dispersing agent, stirring uniformly, and pressing into a sample tablet; wherein the mass ratio of the dispersing agent to the sample is less than or equal to 50 percent;

s2, preparing a standard sample and drawing a standard curve: manufacturing a plurality of crude selenium with different contents and known selenium content into standard sample sheets, measuring the fluorescence intensity value of selenium element of a standard sample by using an energy dispersion X-ray fluorescence spectrometer, and drawing a corresponding relation standard curve of the selenium content of the standard sample and the corresponding fluorescence intensity value;

s3, determining the selenium content of the sample to be detected: and measuring the fluorescence intensity value of the selenium element of the sample to be measured by using an energy dispersion X-ray fluorescence spectrometer, and obtaining the selenium content of the sample to be measured according to the fluorescence intensity value on the standard curve.

In the step S1, the dispersing agent is lithium salt or other reagents meeting the conditions. Preferably, carbonates are used.

Further, the particle size of the dispersing agent is not less than 200 meshes.

The lithium salt has dispersion property, is beneficial to sample piece forming, and particularly can neutralize acid in crude selenium besides the dispersion property of lithium carbonate, reduce corrosivity and play a key role in protecting instrument and equipment. The selection principle of the lithium salt is as follows: 1. water absorption or crystal water generation is not easy; 2. the granularity is not less than 200 meshes; 3. no spectral interference is generated.

In the step S1, the pressure of a pressing sample is 10-30 t, and the time for keeping the pressing sample is 10-30 s. By adopting the sample pressing pressure in the range, the sample can be pressed and formed, and the sample piece can not be broken due to overlarge pressure.

In the step S3, the spectral line selected for measuring the fluorescence intensity value of the sample is K_βA wire. Generally, the L-line is used by those skilled in the art for measurement, but the L-line is not suitable for measurement of the selenium content in the crude selenium, mainly because the selenium concentration in the crude selenium is not suitable. K line includes K_αLine and K_βLine, however K_αThe curve of the line is bent due to the excessively high value of the fluorescence intensity meter, and the deviation of the measurement result is large. Therefore, K is selected for the invention_βAnd the linearity of the standard curve is good, and the measurement result is accurate.

And S2, the selenium content of the standard sample group is distributed in a gradient manner.

Compared with the prior art, the invention has the following beneficial effects:

the preparation of the sample tablet of the invention is different from the traditional technical scheme, and in order to obtain the sample tablet with a firm and stable structure in the pressing process of the common sample tablet, an adhesive with polymerization property is often adopted to obtain a tablet with a compact structure. The invention uses the dispersant (lithium salt) with dispersion property for the molding of the sample wafer, the molded sample wafer is uniform and compact, the surface is flat and smooth, and the invention is suitable for the energy dispersion X-ray fluorescence spectrometer to detect the selenium content in the crude selenium. On the basis, the detection method disclosed by the invention is short in detection time, and detection can be completed within 2 h.

According to the detection method, the lithium salt is added into the sample, so that the damage of acid gas to an instrument is avoided, and particularly, when a vacuum detection environment is involved, the escape of corrosive gas is effectively avoided. And the result data does not need background correction, and the method has the advantages of environmental friendliness, simplicity, convenience and rapidness and accurate analysis result.

The invention establishes the method for measuring the selenium content in the crude selenium by the energy dispersion X-ray fluorescence spectrometer and optimizes the spectral line selection, so that the method has good precision and can meet the rapid detection requirement of industrial production.

The energy required by the energy dispersion X-ray fluorescence spectrometer is very low, and the power is lower than 10W, so that the low energy can further reduce the escape of volatile gas. In addition, in the detection method, a harsh detection environment is not required, for example, an instrument room with strictly controlled temperature and humidity is not required, and a reagent causing environmental pollution is not required to be used, so that the number of devices involved in the detection process is small, the detection process is greatly simplified, the detection cost is reduced, and the detection efficiency is improved.

Detailed Description

The present invention is further explained and illustrated by the following embodiments, which should be understood to make the technical solution of the present invention clearer and easier to understand, and not to limit the scope of the claims.

The instrumentation conditions are as follows in table 1:

TABLE 1 Instrument Condition

Measuring line	Voltage of	Electric current	Filter disc	Detection mode
					Kβ	50kv	63μA	Ag	General of

And measuring the fluorescence intensity value of the crude selenium with known selenium content as a standard sample under the selected instrument condition and drawing a standard curve. 3 coupons were pressed per standard sample and tested 3 times.

Establishment of a measurement method:

the intensity values of crude selenium samples with known content as standard substances were measured under the above selected instrument conditions and a standard curve was drawn. To obtain a stable calibration curve, 3 blocks were pressed per calibration point and measured 3 times.