A method that uses primary X-ray photons or other microscopic ions to excite atoms of the substance being measured, causing them to produce fluorescence (secondary X-rays) to perform compositional analysis of the materials and research on the chemical state. According to different excitation, dispersion and detection methods, it is divided into X-ray spectroscopy (wavelength dispersion) and X-ray energy spectroscopy (energy dispersion). According to different dispersion modes, X-ray fluorescence analyzers are divided into X-ray fluorescence spectrometers (wavelength dispersion) and X-ray fluorescence spectrometers (energy dispersion).
The ultimate goal of studying ocean polymetallic nodule mineral resources is to discover the location of mineral deposits, delineate the extent of the mining area and assess ore reserves, grade, abundance and covererture of the ore. Make an assessment. A large amount of experimental research work and the final evaluation report must be carried out after returning to land. Therefore, the observations, tests and test instruments and equipment involved in this section only describe on-site observations, tests and test instruments and equipment. As for the final investigation of mineral resources, the assessment should also apply more detailed and precise analysis and identification.
3.4.1 On-site sample processing
The various geological samples collected will be used for on-site observation of the exploration of oceanic polymetallic nodules and various types of identification and analysis after their return. to land. Different types of geological samples will be processed in different ways, described below:
Since sediment samples are generallyUsually processed using grabs with or without cable, gravity sampling tubes and gravity piston sampling tubes are used for processing. Therefore, once the samples have been removed from the water and placed on the working surface of the ship's deck, corresponding observations and descriptions should be carried out immediately. Column sediment samples should be sealed and packaged as soon as possible and stored at specified temperatures and temperatures. Humidity conditions. Column sediment samples should not be stored upside down. When dividing samples, it is necessary to maintain the integrity of the cross section and prevent the collected samples from being exposed to various types of contamination. Cylindrical samples collected by gravitational piston samplers are generally longer. When collecting echaPlease note, plastic-coated pipes in the outer packaging are subject to bending and deformation and should be straightened with a pipe straightener. Additionally, sediment samples often contain a large amount of organic matter and microorganisms, which are prone to decomposition and deterioration when stored at room temperature. They should therefore generally be stored at an ambient temperature of around 4°C.
Samples of rocks and polymetallic nodules are generally collected using trawls or sampling boxes. Once the collection operation is completed, the rock and nodule samples should be separated, characterized and processed immediately, then stored under specified conditions after being packaged.
In addition to storing various water samples collected by water collectors at specified temperatures, samples used forMicrobial research also requires special treatment.
3.4.2 Observation and description of samples
Describe the different samples taken in accordance with the requirements of the specifications for the survey of oceanic polymetallic nodules.
3.4.3 On-site testing and recording of geological samples
This includes naked eye identification, microscopic identification, simple chemical analysis and X-ray fluorescence analysis and other elements. Naked eye identification of sediments requires observing the color, structure and texture of the sediments.For biological relics and buried nodules, sketches or photographs of significant structural phenomena should be made; After the polymetallic nodule samples are collected from the seabed and brought to the deck, the following contents should be described in the description: the color of the sample, the sizeparticles of nodules, morphological types of nodules, surface structure of nodules and appearance of nodules, etc.
The survey work of each trip should be equipped with experienced geologists for on-site observation and description, as well as on-site microscopic identification of various geological samples. The work of on-site identification of sediment samples consists of making smears and identifying: detrital mineral composition, rock cuttings, gravels, micro-nodules, micro-paleontological species, etc. ; research work on rocks is mainly carried out after returning to land; . During the trip, the rocks The on-site measurement work mainly focuses on the preliminary naming of the rocks and the general description of the lithology.
In the process of exploring oceanic polymetallic nodules, simple on-site chemical analysis is oftenused. The analysis objects are mainly sediments, surface waters, bottom waters, pore waters and water samples at different depths. Analysis items include: pH value, Eh value, total alkalinity, salinity, chloride, dissolved oxygen, oxygen saturation, chemical oxygen consumption, silicon, phosphorus, nitrate, nitrite, ferrous iron, ferric iron, the ratio of high to low price iron, etc.
X-ray fluorescence analysis is an extremely important method for on-site analysis of oceanic polymetallic nodules. The purpose of on-site analysis is to determine the content of useful metallic elements such as Mn, Fe, Cu, Co, Ni, etc., to meet the needs of on-site resource evaluation and to enable the scientist in leader to take appropriate action. adjustments to the organization of the on-site exploration process. By taking as exemple the Haiyang 4 survey ship, the ship is equipped with a fully automatic Rigaku3080E-3 X-ray fluorescence analyzer, which can measure the content of 25 elements, including Mn, Fe, Cu, Co and Ni. On-site X-ray fluorescence analysis work during several trips has proven that it is an indispensable rapid analysis and testing method. Of course, better measurement results can be obtained using X-ray fluorescence spectrometry or X-ray energy spectroscopy.