RU2616227C1 - Method for determining spectral radiation composition of intrinsic and extrinsic defects in quartz raw material - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: sampling the quartz raw materials, calcining, obtaining luminescence spectra of the prepared samples under X-ray excitation (X-ray fluorescence spectra) are performed. Calcining is performed up to 500°C, the luminescence spectra of the prepared samples are prepared under X-ray excitation in the optical wavelength range of 200-800 nm, the spectral composition of the sample radiation is compared in the calcined and uncalcined samples at different X-radiation (irradiation) time, and the spectral composition of the intrinsic defect radiation is determined according to the radiation intensity enhance in the X-ray bands (λ, nm) 280, 320-340, 360-380, 390-400, 450-470 in the calcined samples; the spectral composition of the impurity defect radiation is determined according to the radiation intensity enhance in the X-ray bands (λ, nm) 330-360, 370-390, 390-420, 420-440, 470-520, 510-570 after the repeated irradiation.

EFFECT: providing the opportunities to increase rapidity and reliability of the preliminary assessment of the quartz raw material quality.

6 dwg

Description

The invention relates to the field of geology, development and use of mineral deposits and can be used in the early stages of exploration for preliminary assessment of the quality of quartz raw materials. Natural quartz raw materials and especially pure quartz concentrates obtained from them are widely used in various high-tech industries - radio-electronic, semiconductor, lighting, optical, etc. The issues of assessing the quality of raw materials at the early stages of geological exploration remain one of the most relevant. The most important quality indicators of quartz raw materials suitable for obtaining high-purity quartz concentrates are the concentrations of impurity elements. They create impurity defects (structural impurities) in quartz. It is known that quartz is characterized by a wide variety of structural impurities or impurity defects (Al, Ge, Ti, alkali metal ions, hydroxyl groups, etc.) and intrinsic defects. To typify natural quartz raw materials by properties that determine the quality of the concentrate, it is necessary to determine the species composition of intrinsic and impurity defects in quartz. A luminescent method for studying the structural imperfection of quartz is known, i.e. a method for determining the spectral composition of the radiation of impurity defects in quartz raw materials, which consists in the fact that according to the data of X-ray and thermoluminescent analyzes, the content of SiO4 / Na + and AlO4 / Li + centers is judged (Votyakov S.L., Krokhalev V.Ya., Purtov V. K., Krasnobaev A.A. Luminescent analysis of the structural imperfection of quartz // Ekaterinburg: UIF "Nauka", 1993. - pp. 30-33). Positive in the known method is that in the work the centers of luminescence are reflected in detail, reflecting the degree of microdefectiveness of quartz. The disadvantage is the fact that the role of AlO4 / Na + centers is underestimated and the role of intrinsic defects in quartz (excited oxygen states), which can be intensely manifested in the X-ray luminescence spectra of highly pure quartz, is not taken into account. A known method for determining the composition of intrinsic and impurity defects in quartz raw materials is that monomineral samples of quartz are sampled, subjected to heat treatment, irradiated with gamma rays at a dose converting isomorphic aluminum to the paramagnetic state, measured by electron paramagnetic resonance (EPR) concentration structural centers in the selected samples (Rakov L. T. et al. "A new method for assessing the quality of quartz raw materials", Exploration and protection of mineral resources, 1993, N 7, p. 36-38). The disadvantage of this method is that it includes a number of complex operations: irradiation of quartz samples with gamma rays, EPR measurement of the concentration of structural aluminum centers, high-temperature processing of samples and significant costs of the investigated material.

The closest in technical essence is a method for assessing the quality of quartz raw materials (patent RU No. 2400736, publ. 09/27/2010, IPC GO1N23 / 223) (prototype), including the selection of mono fractions of quartz, preliminary calcination to a temperature of 350-4500 ° C, obtaining an X-ray luminescence spectrum calcined quartz in the spectral wavelength range of 350-550 nm, followed by an assessment of the defective structure and quality of the quartz raw material by the ratio of the emission of impurity and intrinsic defects. The disadvantage of this method is the fact that the luminescence of intrinsic and impurity defects is determined in a narrow wavelength range. The objective of the present invention is to develop a method for determining the spectral composition of radiation of intrinsic and impurity defects in quartz raw materials in order to increase the expressivity and reliability of a preliminary assessment of the quality of quartz raw materials. The problem is solved in that, according to the prototype, quartz monofractions are selected, calcined, followed by excitation of x-ray luminescence, but unlike the prototype, x-ray luminescence is excited in a wider wavelength range of 200-900 nm in non-roasted and calcined samples using different x-ray (irradiation) times , and determine the presence of intrinsic defects (excited oxygen states) by amplification after calcination of the X-ray luminescence bands (or any of them) with maximum radiation at (λ, nm): 280, 320-340, 360-380, 390-400, 450-470, 620, 670-680; and the presence of impurity defects in the presence of X-ray luminescence bands (or any of them), amplifying after repeated irradiation with maximum radiation at (λ, nm): 330-360, 370-390, 390-420, 420-440, 470-520, 510 -570.

The invention is illustrated by illustrations.

FIG. 1 - Luminescence centers in quartz;

FIG. 2 - X-ray luminescence spectra of quartz (Argazinskoye deposit, sample No. Ar-151-12): the effect of repeated irradiation (RL1-1) and calcination (RL2) on the luminescence of quartz;

FIG. 3 - X-ray luminescence spectra of quartz (Kuznechikhinskoye deposit, sample No. 1): RL1 - x-ray luminescence of an unpicked sample (irradiation time - 8 minutes); RL1-1 - X-ray luminescence of the same sample, re-irradiated (re-X-ray) (exposure time - 16 minutes);

FIG. 4 - X-ray luminescence spectra of quartz (Kuznechikhinsky deposit, sample No. 1): RL1 - x-ray luminescence of an unpalcined sample; RL2 — X-ray luminescence of a sample calcined to 500 ° C;

FIG. 5 - X-ray luminescence spectra of quartz (Ufa deposit, sample No. Uf-133-12): the effect of repeated irradiation (RL1-1) and calcination (RL2) on the luminescence of quartz;

FIG. 6 - X-ray luminescence spectra of quartz (Ufa deposit, sample No. Uf-122-12): the effect of repeated irradiation (RL1-1) and calcination (RL2) on the luminescence of quartz.

The table in figure 1 gives an interpretation of the possible centers of luminescence in quartz. The authors of the present invention experimentally established that a distinctive feature of the luminescent method for determining the spectral composition of the radiation of intrinsic and impurity defects in quartz raw materials is preliminary calcination and the use of x-ray irradiation of different times, which makes it possible to isolate intrinsic and impurity defects and determine their fraction in luminescence. The luminescence intensity associated with intrinsic defects in quartz increases after preliminary calcination, and the luminescence associated with a structural impurity in quartz increases with increasing irradiation time upon repeated x-raying. Without additional laboratory effects, the luminescence spectrum of quartz most often represents a wide non-elementary emission band in the optical wavelength range with overlapping spectral characteristics from different radiation centers (Fig. 2, curve RL1).

The following are examples of specific embodiments of the invention.

The studies were conducted on quartz samples taken from quartz veins of the Ural deposits. The URS-55 apparatus and the BSV X-ray tube were used as a source of luminescence excitation. The X-ray luminescence spectra obtained with this excitation were recorded using an MDR-12 monochromator. The radiation intensity is given in relative units. Moreover, 1 relative unit in this case is approximately equal to 10-3 nit. For all samples, X-ray luminescence spectra were recorded in the wavelength range of 200-800 nm and a comparative analysis of the X-ray luminescence spectra obtained before and after calcination to 500 ° C with different irradiation times and with subsequent determination of the spectral composition of the radiation of intrinsic and impurity defects in quartz raw materials was taken into account the data of the table in figure 1. To confirm the data of luminescent analysis, structural impurities were determined in FSUE TsNIIgeolerud and in the Central Design Bureau of the Geological and Geographic Faculty of Tomsk State vennogo University using ICP-MS analysis.

Example No. 1.

A monofraction of quartz weighing 20 mg was prepared (sample No. 1 from the Kuznechikhinsky deposit of the Ural quartziferous province). Monofraction was divided into two parts. For one part, the X-ray luminescence spectrum was recorded in the optical wavelength range of 200-800 nm (without preliminary calcination) - RL1. Then, without turning off the x-ray excitation, for the same half of the sample, the X-ray luminescence spectrum was re-recorded in the optical wavelength range 200-800 nm - RL1-1 (thereby increasing the irradiation time of the sample by 2 times) (Fig. 3). In the absence of luminescence enhancement after repeated irradiation in the wavelength ranges (λ, nm) 330-360, 370-390, 390-420, 420-440, 470-500, 540-580, it was concluded that in sample No. 1 impurity defects (structural impurity) were detected. For the other half of the prepared sample, the X-ray luminescence spectrum was recorded in the optical wavelength range of 200-800 nm after preliminary calcination of the samples to 500 ° С - РЛ2. Next, we compared the obtained X-ray luminescence spectra of non-calcined samples (RL1) and calcined to 500 ° C (RL2) and a noticeable increase in the radiation intensity in calcined samples with respect to non-calcined samples in the wavelength ranges (λ, nm) 280-340, 360-380, 390 -500, 500-700 concluded that there were intrinsic defects and their effect on the luminescence of quartz (Fig. 4). Using the table in figure 1, it was concluded that the spectral composition of the radiation of sample No. 1 is mainly due to radiation centers associated with excited oxygen states (intrinsic defects). The purity of Kuznechikhinsky quartz with respect to structural impurities and their practically absence is confirmed by a number of works (Bydtaeva N.G., Kiseleva PA, Mileeva I.M. Preliminary assessment of the quality of quartz raw materials in order to predict its technological indicators // Results of basic and applied research. Petrozavodsk: Karelian Research Center. - 2006. - P. 117.118; Bydtaeva N.G., Kiseleva PA, Mileeva I.M. Forecasting and prospecting models of deposits of highly pure quartz // Russian Geology, 2006, No. 4. P. 57-63; Belkovsky A .I. Minerageny of deposits especially of the quartz of the “Ufaleysky” type (Central Ural uplift, Ufaleysky metamorphic block, Middle Urals) // Lithosphere, No. 6. 2013. P. 78.79).

Example No. 2

A monofraction of quartz weighing 20 mg was prepared (sample No. Uf-133-12 from the Ufa deposit of the Ural quartziferous province). Monofraction was divided into two parts. For one part, the X-ray luminescence spectrum was recorded in the optical wavelength range of 200-800 nm (without preliminary calcination) - RL1. Then, without turning off the X-ray excitation, for the same half of the sample, the X-ray luminescence spectrum was re-recorded in the optical wavelength range 200-800 nm - RL1-1 (thereby increasing the irradiation time of the sample by 2 times) (Fig. 5). On the increase in luminescence after repeated irradiation in the wavelength ranges (λ, nm) 330-360, 420-440, 470-500, it was concluded that impurity defects (structural impurity) that form centers are present in the sample UV-No. radiation of TiO4 / Li + (330-360 nm), AlO44- / Na + (420-440 nm), AlO44- / Li + (470-500 nm) (Fig. 1). For the other half of the prepared sample, the X-ray luminescence spectrum was recorded in the optical wavelength range of 200-800 nm after preliminary calcination of the samples to 500 ° С - РЛ2. Next, we compared the obtained X-ray luminescence spectra of non-calcined samples (RL1) and calcined to 500 ° C (RL2) and a noticeable increase in the radiation intensity in calcined samples with respect to not calcined in the wavelength range 360-380 nm, concluded that there were intrinsic defects and their influence on the luminescence of quartz. Using the table in figure 1, we concluded that the spectral composition of the radiation of sample No. Uf-133-12 is due both to the centers of radiation associated with excited oxygen states (360-380 nm), and with structural impurities: TiO4 / Li +, AlO44 - / Na +, AlO44- / Li +. The conclusion about the presence of structural impurities of Al, Ti, Li, Na in sample No. Uf-133-12 is confirmed by mass spectrometry, according to which, in the sample of quartz No. Uf-133-12 from the Ufa deposit, Al, Ti, Li, Na impurities are present in an amount up to 13.5 ppm (structural impurities were determined in FSUE TsNIIgeolerud and in the Central Design Bureau of the Geological and Geographical Department of Tomsk State University using ICP-MS analysis).

Example No. 3

A monofraction of quartz weighing 20 mg was prepared (sample No.Uf-122-12 from the Ufa deposit of the Urals quartziferous province). Monofraction was divided into two parts. By the method described above, for two prepared parts of monofraction, X-ray luminescence spectra were recorded (Fig. 6). According to a very weak increase in luminescence after repeated irradiation (RL1-1) in the wavelength range of 360-450 nm, it was concluded that a small fraction of impurity defects (structural impurities) were found in sample No. Uf-122-12. Using the table in figure 1, it was concluded that structural impurities that form the luminescence centers of AlO44- / Na +, AlO44- / Li + can be responsible for the 360-450 nm range in the luminescence spectrum (Fig. 1). Next, we compared the obtained X-ray luminescence spectra of non-calcined samples (RL1) and calcined to 500 ° C (RL2) and a noticeable increase in the radiation intensity in calcined samples with respect to not calcined in the wavelength ranges (λ, nm) 360-380, 390-500 conclusion about the presence of intrinsic defects and their effect on the luminescence of quartz. Using the table in figure 1, we concluded that the spectral composition of the radiation of sample No. Uf-122-12 is mainly due to radiation centers associated with excited oxygen states (360-380 nm, 390-500), that is, with their own defects. The conclusion about the presence of an insignificant fraction of Al, Li, Na structural impurities in sample No. Uf-122-12 was confirmed by mass spectrometry, according to which these impurities in the amount of up to 8 ppm are present in this quartz sample from the Ufa deposit (structural impurities were determined in FSUE TsNIIgeolerurud and at Tomsk State University).

Example No. 4

A monofraction of quartz weighing 20 mg was prepared (sample No. Ar-151-12 from the Argazinsky deposit of the Ural quartziferous province). Monofraction was divided into two parts. As described above, for two parts of the monofraction, X-ray luminescence spectra were recorded (Fig. 2). On the increase in luminescence after repeated irradiation in the wavelength ranges (λ, nm) 330-360, 420-440, 470-500, 510-570, it was concluded that impurity defects were detected in sample No. Ar-151-12 (structural impurity ), forming the emission centers of TiO4 / Li +, AlO44- / Na +, AlO44- / Li +, GeО44- / Li + (Fig. 1). Next, we compared the obtained X-ray luminescence spectra of non-calcined samples (RL1) and calcined to 500 ° C (RL2) and, based on a noticeable increase in the radiation intensity in calcined samples with respect to non-calcined ones in the wavelength range 360-380 nm, concluded that there are intrinsic defects and their effect on luminescence of quartz in one range. Using the table in figure 1, we concluded that the spectral composition of the radiation of sample No.Ar-151-12 is mainly due to radiation centers associated with structural impurities TiO4 / Li +, AlO44- / Na +, AlO44- / Li +, GeО44 - / Li + TiO4 / Li +. The conclusion about the presence of structural impurities of Al, Ge, Ti, Li in sample No. Ar-151-12 is confirmed by the data of the mass spectrometry method, according to which in the quartz sample No. Ar-151-12 from the Argazinsky deposit, these impurities are present in an amount up to 80 ppm (structural impurities determined in FSUE TsNIIgeolerud and Tomsk State University).

Thus, the proposed method for determining the spectral composition of the radiation of intrinsic and impurity defects in quartz raw materials using X-ray luminescence spectra obtained at different irradiation times and by comparing the X-ray luminescence spectra of quartz samples not calcined and calcined to 500 ° C allows us to quickly and reliably determine the spectral composition of radiation of intrinsic and impurity defects in quartz raw materials.

Claims (1)

A method for determining the spectral composition of radiation of intrinsic and impurity defects in quartz raw materials, including sampling of quartz raw materials, calcination, obtaining luminescence spectra of prepared samples under x-ray excitation (X-ray luminescence spectra), characterized in that the calcination is performed up to 500 ° C, and luminescence spectra of prepared samples are obtained when x-ray excitation in the optical wavelength range of 200-800 nm, the spectral composition of the radiation of samples in calcined and non-calcined samples is compared and different time X radiation (irradiation) and determining the spectral composition of the radiation intrinsic defects to enhance the radiation intensity in the X-ray bands (λ, nm) 280, 320-340, 360-380, 390-400, 450-470 in the calcined samples; determine the spectral composition of the radiation of impurity defects by increasing the radiation intensity in the X-ray luminescence bands (λ, nm) 330-360, 370-390, 390-420, 420-440, 470-520, 510-570 after repeated irradiation.

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