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Method for detecting content of hexavalent chromium in silicon steel coating

A hexavalent chromium and coating technology, which is applied in the field of inspection and testing technology, can solve the problems of reducing the order quantity of silicon steel products, cumbersome formula calculation, and unsatisfactory, and achieve the effect of reducing testing items, shortening testing time, and speeding up calculation speed

Inactive Publication Date: 2012-12-19
ANGANG STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] Due to the calculation formula of the hexavalent chromium content PP in the above-mentioned coatings, there are not only many parameters, but the calculation of the formula is cumbersome, time-consuming and laborious, and it is limited to domestic testing conditions, such as coating thickness H and coating density M cannot be detected
More importantly, most of the silicon steel coatings produced in my country contain chromium. The current detection method for the hexavalent chromium content is: first, the hexavalent chromium in the coating is precipitated by boiling water and dissolved in solvent water, and then spectrophotometer is used to detect the hexavalent chromium. The method of detecting the concentration of hexavalent chromium in the coating in the solution is tested, but the final unit is μg / ml, which is not consistent with the unit ppm of the ratio of the weight of hexavalent chromium in the coating to the weight of the coating according to the EU ROHS standard Therefore, it is impossible to directly infer whether the hexavalent chromium content in the domestic silicon steel coating complies with the EU ROHS standard. Therefore, it not only directly affects the export of silicon steel products, but also fails to meet the requirements of some domestic users, reducing the order quantity of silicon steel products.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0018] Use a spectrophotometer to detect the concentration C of hexavalent chromium dissolved in solvent water in the coating to be 0.05 μg / ml, add a coating amount conversion program in the fluorescence spectrometer, and use the fluorescence spectrometer to detect the concentration of chromium per unit area in the silicon steel coating. Weight is 0.084 g / m 2 According to the coating liquid preparation ratio, the percentage of chromium in the coating is 7%, and the coating weight T per unit area is obtained by dividing the chromium content by the coating weight of chromium per unit area, which is 1.2 g / m 2 , the total volume V of the solvent used to dilute hexavalent chromium in the process of spectrophotometric detection is 500ml, and the total surface area S of the coating used to detect hexavalent chromium is 0.0252m 2 , and substitute the value into the formula for calculating the hexavalent chromium content in the coating:

[0019] PP= V / S C / T=500 / 0.0252 0.05 / 1.2=826.7...

Embodiment 2

[0022] Use a spectrophotometer to detect the concentration C of hexavalent chromium dissolved in solvent water in the coating to be 0.07 μg / ml, add a coating amount conversion program in the fluorescence spectrometer, and use the fluorescence spectrometer to detect the concentration of chromium per unit area in the silicon steel coating. Weight 0.09 g / m 2 According to the coating liquid preparation ratio, the percentage of chromium in the coating is 7.5%, and the coating weight T per unit area is obtained by dividing the chromium content by the coating weight of chromium per unit area, which is 1.2 g / m 2 , the total volume V of the solvent used to dilute hexavalent chromium in the process of spectrophotometric detection is 500ml, and the total surface area S of the coating used to detect hexavalent chromium is 0.0252m 2 , and substitute the value into the formula for calculating the hexavalent chromium content in the coating:

[0023] PP= V / S C / T=500 / 0.0252 0.07 / 1.2=1157.41...

Embodiment 3

[0026] Because in detection practice, the solvent total volume V used and the total surface area S of the coating used for detection can be constant, for example in embodiment 1,2, V=500ml, S=0.0252m 2 , so the constant A=19841 can be obtained. If the concentration C of hexavalent chromium dissolved in solvent water in the coating is detected by a spectrophotometer is 0.06 μg / ml, and the coating weight T per unit area of ​​silicon steel is detected by a fluorescence spectrometer is 1.2 g / m 2 ,

[0027] According to the simplified formula for calculating the hexavalent chromium content in the coating:

[0028] PP=A C / T=19841×0.06 / 1.2=992.05 (ppm)

[0029] 992.05ppm is less than 1000ppm stipulated in EU ROHS standard, so the hexavalent chromium content in the silicon steel coating meets the standard. Obviously, both the detection process and the calculation process are very simple and easy.

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Abstract

The invention provides a method for detecting the content of hexavalent chromium in a silicon steel coating. The content PP of the hexavalent chromium in the coating is calculated according to the following formula: PP=V / S.C / T, wherein V refers to the overall volume of a solvent for detection; S refers to the overall surface area of the coating for detection; C refers to the concentration of the hexavalent chromium in the coating dissolved in the solvent water, which is obtained through detection by a spectrophotometer; and T refers to the weight of the coating in an area unit of the silicon steel detected by a fluorescence spectrophotometer. If V and S are constant values, PP=A.C / T, wherein A is a constant. The method for detecting the content of hexavalent chromium provided by the invention is capable of realizing calculation by means of the numerical detection values of the spectrophotometry and the fluorescence spectrophotometer; the detection parameters are reduced so that the detection time can be shortened, the detection items are reduced and the calculation speed can be increased; therefore, the method is adaptive to the conventional detection conditions in China and capable of obtaining the value of the content of the hexavalent chromium unified with the standard unit of European Union ROHS (Restriction of the use of certain Hazardous Substances), thereby meeting the export requirements of the silicon steel, satisfying the demands of users and increasing the order quantity of the silicon steel.

Description

technical field [0001] The invention belongs to the field of inspection and testing technology, and in particular relates to a method for detecting the content of hexavalent chromium in the insulating coating on the surface of cold-rolled silicon steel. Background technique [0002] With the rapid development of my country's iron and steel industry, the export quantity and variety of steel products are also continuously expanding, but the following problems that do not correspond to domestic and international standards are also becoming more and more obvious. For cold-rolled silicon steel, the EU ROHS standard strictly limits the content of various environmentally harmful elements, which requires that the content of hexavalent chromium in the insulating coating on the surface of cold-rolled silicon steel should not exceed 1000ppm, but The specific detection equipment and detection method are not given. The formula for calculating the hexavalent chromium content PP in the co...

Claims

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Application Information

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IPC IPC(8): G01N21/31G01N21/64
Inventor 姜福健罗理林棡张本尊李斌
Owner ANGANG STEEL CO LTD