Metal Element Analyzer Principle

At present, the users of the domestic metallurgy, foundry, and machinery industries have the following types of instruments that can be used to analyze trace elements other than carbon and sulfur in metallic materials:

1. Spectrum Analyzer. The advantage is that multiple elements can be analyzed at a time with high precision. The disadvantage is that the price is too high, a set of hundreds of thousands to millions, so currently only a few large companies use.

2. Spectrophotometer. The advantage is that the detection wavelength is easy to choose and the price is not high. The disadvantage is that the test result can not be directly displayed (to be converted); there is no curve to establish the call function, detection of different elements every time to re-calibration; the cuvette into and out of the liquid is inconvenient; the basic knowledge of the operator's chemical analysis requirements Therefore, it cannot meet the needs of on-site on-line inspection and analysis.

3. Colorimetric analyzer. The advantage is that it is easy to use, the price is not high, and the operator's chemical analysis basis is not very demanding. Therefore, it is widely used in the production inspection field analysis. However, because of its historical reasons, there are the following congenital defects.

The electro-optical colorimetric metal element analyzer was developed in China in the 1960s to meet the needs of on-site on-line inspection and analysis of the five major elements (carbon, sulfur, silicon, manganese, and phosphorus) of iron and steel metallurgy. The elemental analyzer was developed for silicon, manganese, and phosphorus (at the time, it was called three-element, and the three channels were fixed at the fixed wavelength to detect silicon, manganese, and phosphorus, respectively). Since silicon, manganese, and phosphorus do not require much wavelength detection, accuracy is not high. Therefore, the three-element analyzer satisfies the need for online on-line analysis of elemental content in the iron and steel metallurgy industry. However, nowadays, materials that need to be tested in various industries include copper alloys, aluminum alloys, and zinc alloys in addition to steel. The elements examined also evolved from silicon, manganese, and phosphorus to copper, chromium, nickel, zinc, magnesium, tungsten, vanadium, and niobium. , titanium, molybdenum, aluminum, arsenic, zirconium, boron, rare earth elements and other elements. The following defects commonly found in traditional photoelectric colorimetric metal element analyzers are increasingly manifested:

1. The measurement wavelength is preset and cannot be adjusted continuously. Although some models can be replaced (by replacing filters or light emitting diodes), it is still cumbersome for the user to meet the element types that exceed the number of channels of the instrument. Or it is particularly inconvenient to test different alloy materials. And not all wavelength filters and LEDs can be purchased, making it difficult to measure certain elements. For example, the measurement of magnesium requires a 576-nm light source, and filters and LEDs of this wavelength are not available.

2. The measurement light source is mostly a DC bulb plus a filter or a cold light emitting diode, and its wavelength accuracy is poor. The wavelength accuracy of the DC bulb plus filter method depends on the filter, and most of the filter elements used in the elemental analyzer can only achieve ±15 nm. The wavelength accuracy of light emitting diodes depends on the diodes used. Most of the errors range from 20 to 30 nm, which does not guarantee the accuracy of analysis and detection.