CN-122016698-A - Method for nondestructively distinguishing kaolinite group minerals based on infrared reflection method

CN122016698ACN 122016698 ACN122016698 ACN 122016698ACN-122016698-A

Abstract

The invention discloses a method for nondestructively distinguishing kaolinite minerals based on an infrared reflection method, and belongs to the technical field of precious stone detection. According to the method, a classification standard of kaolinite group minerals is worked out according to the difference of wave numbers of Si-O characteristic peaks positioned near 1130cm < -1 > and Si-O-Si characteristic peaks positioned near 1005cm < -1 > in an infrared reflection spectrum, the infrared reflection spectrum of kaolinite group minerals to be classified is measured through a Fourier transform infrared spectrometer, and then kaolinite, dickite and nacrite in the kaolinite group minerals are distinguished according to the difference of wave numbers of Si-O characteristic peaks positioned near 1130cm < -1 > and Si-O-Si characteristic peaks positioned near 1005cm < -1 >. According to the invention, the kaolinite group minerals are distinguished according to the difference of wave numbers of Si-O characteristic peaks positioned near 1130cm < -1 > and Si-O-Si characteristic peaks positioned near 1005cm < -1 > in an infrared reflection spectrum, so that the problem that the kaolinite group minerals cannot be distinguished by nondestructive detection in the existing precious stone detection method and can be distinguished only by a detection method of a lossy sample such as infrared transmission spectrum or X-ray diffraction analysis can be solved.

Inventors

WANG ZIXUAN
BAI FENG
AN WENJING
Li Luanxiao
LIU YU
Li Gengyang

Assignees

中国地质大学（北京）

Dates

Publication Date: 20260512
Application Date: 20260130

Claims (3)

1. The method for nondestructively distinguishing the kaolinite mineral based on the infrared reflection method is characterized by comprising the following steps of: S1, acquiring an infrared reflection spectrum of a kaolinite mineral to be distinguished; S2, determining a first peak position of a Si-O characteristic peak at 1130cm -1 and a second peak position of a Si-O-Si characteristic peak at 1005 cm -1 from the infrared reflection spectrum; s3, calculating a wave number difference value between the first peak position and the second peak position; s4, judging the category of the kaolinite group mineral according to the wave number difference value and the classification standard; The classification standard specifically comprises the following steps: (1) When the difference of the wave numbers is less than or equal to 122cm -1 , judging that the sample comprises kaolinite components; (2) When the difference of the wave numbers is more than 122cm -1 and less than 125cm -1 , judging that the sample comprises the mixture components of dickite and kaolinite; (3) When the difference value of the wave numbers is more than or equal to 125cm -1 and less than or equal to 127cm -1 , judging that the sample comprises the dickite component; (4) When the difference in wave numbers is greater than 127cm -1 , the sample is judged to include the nacreous ceramic stone component.
2. The method for nondestructively distinguishing kaolinite group minerals based on the infrared reflection method according to claim 1, wherein in S1, the infrared reflection spectrum is measured by fourier transform infrared spectrometer.
3. The method for nondestructively distinguishing kaolinite minerals based on an infrared reflection method according to claim 2, characterized in that the wave number range measured by the infrared reflection method by a fourier transform infrared spectrometer is 400-2000 cm -1 , the resolution is not more than 4cm -1 , and the scanning times are not less than 16.

Description

Method for nondestructively distinguishing kaolinite group minerals based on infrared reflection method Technical Field The invention relates to a method for nondestructively distinguishing kaolinite minerals based on an infrared reflection method, belonging to the technical field of precious stone detection. Background The kaolinite group is one of the sub-groups of the layered silicate minerals of the oxygenic mineral major class of silicate minerals, and comprises four minerals halloysite, kaolinite, dickite (also known as dickite) and nacrite. The three minerals of kaolinite, dickite and nacreous ceramic are extremely small in distinction and are difficult to distinguish by a conventional nondestructive testing means, but distinguishing the kaolinite, dickite, nacreous ceramic and other mineral components has important identification significance in identifying seal stones such as goddessite, tian Huang and laos stone. At present, in the identification process, kaolinite and dickite can be distinguished only by the test results of an X-ray diffraction analysis or an infrared transmission method, and the X-ray diffraction analysis and the infrared transmission method need grinding sample powder, damage the sample and do not meet the requirements of nondestructive detection in jewelry detection. Therefore, a nondestructive detection method is urgently needed to replace an X-ray diffraction analysis method and an infrared transmission method, and the purpose of nondestructively distinguishing kaolinite, dickite and nacreous ceramic stone is achieved. Disclosure of Invention In order to solve the problems, the invention provides a method for distinguishing kaolinite group minerals based on an infrared reflection method, namely, classifying standards of the kaolinite group minerals are made according to the difference of wave numbers of Si-O characteristic peaks positioned near 1130cm < -1 > and Si-O-Si characteristic peaks positioned near 1005cm < -1 > in the infrared reflection spectrum, infrared reflection spectrums of the kaolinite group minerals to be classified are measured through a Fourier transform infrared spectrometer, and kaolinite, dickite and nacrite in the kaolinite group minerals are distinguished according to the difference of wave numbers of the Si-O characteristic peaks positioned near 1130cm < -1 > and Si-O-Si characteristic peaks positioned near 1005cm < -1 >. In order to achieve the above purpose, the present invention provides the following technical solutions: S1, acquiring an infrared reflection spectrum of a kaolinite mineral to be distinguished; S2, determining a first peak position of a Si-O characteristic peak positioned near 1130cm -1 and a second peak position of a Si-O-Si characteristic peak positioned near 1005 cm cm -1 from an infrared reflection spectrum; s3, calculating a wave number difference value between the first peak position and the second peak position; s4, judging the category of the kaolinite group mineral according to the wave number difference value and the classification standard; the classification standard of the kaolinite group mineral is as follows: If the difference between the wave numbers of the Si-O characteristic peak located near 1130cm -1 and the Si-O-Si characteristic peak located near 1005cm -1 is 122cm -1 or less, the main component of the sample is kaolinite; If the difference between the wave numbers of the Si-O characteristic peak located near 1130cm -1 and the Si-O-Si characteristic peak located near 1005cm -1 is greater than 122cm -1 and less than 125cm -1, the main component of the sample is a mixture of dickite and kaolinite; If the difference between the wave numbers of the Si-O characteristic peak located near 1130cm -1 and the Si-O-Si characteristic peak located near 1005cm -1 is 125cm -1 or more and 127cm -1 or less, the main component of the sample is dickite; If the difference between the wave numbers of the Si-O characteristic peak located near 1130cm -1 and the Si-O-Si characteristic peak located near 1005cm -1 is greater than 127cm -1, the main component of the sample is nacreous argillite; The wave number range of the Fourier transform infrared spectrometer for infrared reflection method test is 400-2000 cm -1, the resolution is less than or equal to 4cm -1, and the scanning times are not less than 16. Compared with the prior art, the invention has the following beneficial effects: According to the method, the classification standard of the kaolinite group minerals is worked out according to the difference of the Si-O characteristic peaks positioned near 1130cm -1 and the Si-O-Si characteristic peaks positioned near 1005cm -1 in the infrared reflection spectrum, the infrared reflection spectrum of the kaolinite group minerals to be classified is measured through a Fourier transform infrared spectrometer, and then the kaolinite, dickite and nacrite in the kaolinite group minerals are distinguished according to the difference of th