Spectroscopy originated in the 17th century, and in 1666 the physicist Isaac Newton conducted an experiment on the dispersion of light. He introduced a beam of sunlight in a dark room, let it pass through a prism, and on the self-screen behind the prism, he saw the red, orange, yellow, green, orchid, indigo, violet seven colors of light dispersed in different positions - that is, the formation of a rainbow, a phenomenon called spectroscopy, and this experiment is the origin of spectroscopy. Since Newton, has not attracted attention. To 1802 British chemist Wollaston found that the solar spectrum is not a rainbow, but is cut by some black lines.
In 1814 when German optical instrument experts studied the relative positions of the black spots in the solar spectrum . Plotted those major black lines on a spectral map.
In 1826, when Terbot studied the spectra of sodium and potassium salts on alcohol lamps, he pointed out that the emission spectrum is the basis of chemical analysis, and that the red spectrum of potassium salts and the yellow spectrum of sodium salts are properties of this element. To 1859 Kirchhoff and Bunsen in order to study the spectra of metals themselves designed and manufactured a perfect spectroscopic device, this device is the world's first practical spectroscopic instrument, the study of flames, sparks in a variety of metal spectral lines, thus establishing the initial foundation of spectral analysis.
From 1860 to 1907, the flame and electric spark discharge found the alkali metal element cesium Cs, 1861 and found rubidium Rb and thallium Tl, 1868 and found indium In and helium He. 1869 and found nitrogen N. 1875 ~ 1907 and successively found gallium Ga, potassium K, thulium Tm, praseodymium Pr, polonium Pe, samarium Sm, yttrium y, lutetium Lu and so on.
In 1882, Roland invented the concave grating, that is, the scratch is engraved directly on the concave sphere. Concave grating is actually the optical instrument imaging system components into one efficient element, it solves the prism spectrometer encountered at the time of the insurmountable difficulties. The introduction of concave gratings not only simplified the structure of the spectroscopic instrument, but also improved its performance.
Borel's theory played a role in spectral analysis, its excitation process of the spectrum, the intensity of spectral lines, etc. to propose a more satisfactory explanation.
The application of shifting from the determination of the intensity of the spectral lines to the measurement of the relative intensity of the spectral lines created the basis for the development of the spectral analysis method from qualitative analysis to quantitative analysis. Thus, the spectral analysis method gradually came out of the laboratory and was applied in the industrial sector.
After 1928, as a result of spectral analysis into an industrial analysis method, spectral instrumentation has been rapid development, on the one hand, to improve the stability of the excitation light source, on the other hand, to improve the performance of the spectral instrument itself.
The earliest light source is the flame excitation spectroscopy; later on the development of the application of simple arc and spark for the excitation of light source, in the last century, the thirties and forties to improve the use of controlled arc and spark for the excitation of light source, improve the stability of the spectral analysis. The development of industrial production, the progress of spectroscopy, prompting further improvement of optical instruments, and the latter in turn reacted to the former, promoting the development of spectroscopy and the development of industrial production.
The sixties photoelectric direct-reading spectrometer, with the development of computer technology began to develop rapidly, in 1964 ARL demonstrated a set of digital computing and control readout system. Due to the development of computer technology, the development of electronic technology, miniaturization of electronic computers and microprocessors and the emergence of popularity, cost reduction, etc., in the 1970s spectroscopic instruments using computer control, which not only improves the analysis of precision and speed, but also the results of the analysis of the data processing and analysis of the process of automation control.
After the liberation, China's spectroscopic instrument industry from scratch, from small to large, has been the development of a leap, and has a certain scale, and the world's advanced technology to survive the competition, the social commodities competition in the development.
In 1958, the trial production of spectroscopic instruments began, the production of a medium-sized quartz spectrograph, large spectrograph, monochromator. Chinese academy of sciences institute of optical machinery began to study the engraved grating, 59 years Shanghai optical instrument factory, 63 years Beijing optical instrument factory began to study the engraved grating, 63 years the development of photolithography success. 1966-1968 Beijing optical instrument factory and Shanghai optical instrument factory successively developed a medium-sized planar grating spectrometer and a meter planar grating spectrometer and photoelectric reading head. 1971-1972 by the second Beijing optical instrument factory. In 1971-1972 by the second Beijing Optical Instrument Factory successfully researched and developed a WZG-200 plane grating light meter, the end of China can not produce photoelectric direct reading spectrometer history.
Since the eighties, China's foundry industry began to introduce photoelectric direct-reading spectrometer as a means of analyzing the chemical composition control in the melting process, and gradually replaced our traditional wet chemical analysis, has developed to small and medium-sized enterprises have gradually used spectroscopy with the pre-furnace analysis. The introduction of foreign casting production line has been equipped with special spectral analysis equipment, as a complete set of equipment into China, this is the foundry industry on the development of increasingly stringent requirements for quality control is the inevitable result of the development, but also photoelectric spectral analysis of its own advantages determine the technology since its introduction in 1945, after fifty-six years and the reason for the enduring. As we all know, atomic emission spectrometry is the principle used in the analysis of the elements in the sample with an electric arc (or spark) of high temperature from the solid state directly gasification and excitation and emission of the characteristic wavelengths of the elements, with the grating spectroscopy, according to the wavelength arrangement of the "spectrum", the characteristics of these elements of the spectral line through the exit slit, shot into the respective photoelectric The characteristic spectral lines of these elements pass through the emitting slit and are shot into the respective photomultiplier tubes, the optical signals become electrical signals, and the electrical signals are integrated by the instrument's control and measurement system and converted into analog/digital format, and then processed by the computer, and the percentage content of each element is printed out. From the above principle can be seen atomic emission spectrometry analysis, has its own unique, especially suitable for analysis with the advantages of pre-furnace, so that its development has become an essential means of analysis of metal smelting and foundry industry, its characteristics are as follows:
First, the furnace to take the sample as long as the grinding off the surface of the oxide skin, solid samples can be placed on the sample stage excitation, eliminating the need for chemical analysis of the trouble of drilling specimens. For aluminum and copper, zinc and other non-ferrous metal samples, can be used to small lathe car to the surface of the oxide skin can be.
Second, from the sample excitation to the computer to report the elemental analysis content only 20-30 seconds, the speed is very fast, which is conducive to shorten the smelting time, reduce costs. Especially for those elements that are easy to burn, it is easier to control its final composition.
Third, all the elements to be analyzed in the sample (several or even more than a dozen) can be analyzed at the same time, for the complexity of the product grade, the more elements required to be analyzed, the better the calculation, and good economic efficiency.
Fourth, the analysis precision is very high, can effectively control the chemical composition of the product to ensure that it can meet the national standard specifications, and even the alloy composition can be controlled to the specifications of the lower limit to save the consumption of intermediate alloys or ferroalloys. Fifth, the analysis data can be printed from the computer or stored in the floppy disk, as a long-term record.
In short, from a technical point of view photoelectric spectral analysis, it can be said that so far there is no more effective than it can be used for rapid analysis of the furnace before the instrument, with so many features and can replace it. So the world smelting, casting and other metal processing enterprises are competing to use this type of instrument to become a regular means of analysis, from ensuring product quality, from the economic benefits, it is very favorable analysis tool.
