吸光度定位光度法测定锰铁中的锰

在“保持‘人、机、料、法、环’各个影响因素在同批样品测定中同一性”的条件下:1) 制备一个标准样品的“母液”;2) 以“微滴”方式滴取“母液”制备“显色系列”,展现其吸光度值域区间;3) 将被测样品的最高含量匹配吸光度最大值,组建“显色系列”相应的“含量系列”;4) 根据被测样品含量范围,选取“含量系列”中的两个样品,作为“两标准光度法”的两个标准。以其含量最高样品的“母液”用量为准,滴取被测样品的“母液”,作为被测样品并实施测定。此方法简便、高速、高效、环保。“小样本”测定结果的极差R为0.92%,不确定度U95为0.22% (k = 3),相对标准偏差RSD为0.28% (n = 8)。Under the condition of “maintaining the consistency of various influencing factors of ‘human, machine, material, method, and environment’” in the determination of the same batch of samples: 1) Prepare a “mother liquor” for a standard sample;2) Drip the “mother liquor” in a “droplet” manner to prepare a “color series” and display its absorbance range;3) Match the highest content of the tested sample with the maximum absorbance value, and form a “content series” corresponding to the “color series”;4) Based on the content range of the tested sample, select two samples from the “content series” as the two standards for the “two standard photometry method”. Based on the amount of “mother liquor” used in the sample with the highest content, drop the “mother liquor” of the tested sample as the tested sample and carry out the measurement. The method is simple, fast, efficient, and environmentally friendly. The range R of the “small sample” measurement results is 0.92%, the uncertainty U95 is 0.22% (k = 3), and the relative standard deviation RSD is 0.28% (n = 8).

Petrogenetic contrastive studies on the Mesozoic early stage ore-bearing and late stage ore-barren granites from the southern Anhui Province

Yanshanian magmatisms are intensive in the southern Anhui Province and can be divided into early （152-137 Ma） and late （136-122 Ma） stages. A Yanshanian granitic zone was found to crop out along Qingshan to Changgai areas in the Ttmxi district in Field investigation which has a genetic link with molybdenum multiple metal mineralization. To be a representative syenitic granite in the southern Anhui Province, the Huangshan pluton has not been found so far to have any genetic link with mineralization. Zircon LA-ICP-MS dating indicate that the four granitic bodies from the Qingshan-Changgai zone have concurrent formed ages from 140~：4 to 141~2 Ma, belonging to the Yanshanian early stage magmatism. However, the Huangshan granite is dated to be 12912 Ma, belonging to the Yanshanian late stage magmatism. The Qingshan-Changgai granites show high SiO2 and K20 contents, low P205 contents and middle A12O3 contents and are high-K calc-alkaline series metaluminum I-type granite. These rocks are characterized by enrichments in the large ion lithophile elements and light rare earth elements （REE）, depletions in the high field-strength elements, and middle degree negative anomalies of Eu, geochemical features of arc or continent crustal derived magma affinities. These rocks have 87Sr/StSr（t） ratios from 0.7120 to 0.7125,εNd（t） values from -7.24 to -4.38 and zircon εHf（t） values of -4.4 to 6.7, similar to that of the coeval ore-bearing granodiorites in the southern Anhui Province. Integrated geochemical studies indicate that the Yanshanian ore-bearing granodiorites were formed by partial melting of the Meso-Neoproterozoic accreted thickened low crust. Meanwhile, the Qingshan-Changgai granites were formed through a AFC process of plagioclase＋amphibole＋Shangxi Group of magmas that formed the ore-bearing granodiorites. The Huangshan granites are characterized by high SiOz and K2O contents, moderate Al2O3 contents, seagull shape REE distributed pattern and distinct Eu negative abnormities. Comparing with the Qingshan-Changgai granites, the Huangshan granites show more Ba, Sr, P, and Ti negative abnormities with no Nb and Ta depletions and are high-K calc-alkaline series metaluminum A-type granite, εHr（t） values of the Huangshan granites are from -6.6 to -1.2, similar to that of the early stage ore-bearing granodiorites, indicating that they were also formed by anatexis of the Meso-Neoproterozoic accreted crust, but their magma sources might be residual granulitic crust which ever underwent Yanshanian early stage I-type intermediate-acid magma extraction. Comparing studies on the two stages granites indicate that the early stage granites derived from a relative thickened low crust under a lower temperature condition. Their magma sources were Meso-Neoproterozoic accreted crust which enriched in ore-forming materials and further became more enriched through processes of magma AFC evolution. However, the late stage A-type granites originated from relative shallow crust under a higher temperature condition. Their magma source was depleted in ore-forming materials due to the early stage magma extraction and thus had weak ore-forming capacity. From early to late stage, the magmatisms tectonic setting translated from post-orogenic to anorogenic and the later corresponded to a back-arc extensional setting as increase of the slab subducted angle of the Paleo-Pacific plate.