Goldschmidt Abstracts最新文献_第5页

Kinetic Modeling of pH and Temperature Effects on Silica Polymerization pH和温度对二氧化硅聚合影响的动力学模拟

Goldschmidt Abstracts Pub Date : 2020-01-01 DOI: 10.46427/gold2020.2529

Shota Tajima, Tatsuya Kato, S. Fuchida, T. Kitagawa, C. Tokoro

{"title":"Kinetic Modeling of pH and Temperature Effects on Silica Polymerization","authors":"Shota Tajima, Tatsuya Kato, S. Fuchida, T. Kitagawa, C. Tokoro","doi":"10.46427/gold2020.2529","DOIUrl":"https://doi.org/10.46427/gold2020.2529","url":null,"abstract":"Silica scale formation is one of the significant problems for the practical operation of geothermal plants because geothermal fluids used for the electricity generation often contain a high amount of silicic acid. Acidification of geothermal fluid (pH<6) is a general process to avoid silica scale formation; however, this could cause corrosion of metal pipes. In this study, we investigated the effect of pH and temperature (298–353 K) on the polymerization rate of silica and examined optimal pH and temperature conditions on the treatment process of waste geothermal fluids. When silica solution (500 mg/dm 3 ) reacted at different pH 3, 6, and 9 for 336 h, initial decrease patterns of dissolved silica concentrations (<0.1um) were different in pH condition at 298 K; it reduced to 200 and 400 mg/dm 3 at pH 6 and 9 within 48 h, respectively, whereas did not change at pH 3. This initial decrease of dissolved silica concentration is related to the nucleus growth in the early stage of silica polymerization, followed by the aggregation as the latter stage of the polymerization. At pH 6, since nucleus growth was most promoted at 298 K, the pseudo-equilibrium concentration of dissolved silica concentration gradually increased with increasing temperature and was 400 mg/dm 3 at 333 K. However, its rates were almost same at the pH. Furthermore, the induction periods until start to nucleus growth were prolonged with increasing temperature and its reaction did not start at 353 K. The pseudo-equilibrium concentration was represented the Van't Hoff equation. On the other hand, at pH 9, the pseudo-equilibrium concentration reduced from 400 mg/dm 3 at 298 K to 300 mg/dm 3 at 313 K, while no polymerization was found over 333 K. The","PeriodicalId":12817,"journal":{"name":"Goldschmidt Abstracts","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75620654","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Petrogenesis and Element Mobility of Neoarchean Alkaline Granitic Gneisses in the Southeastern Margin of the North China Craton 华北克拉通东南缘新太古代碱性花岗质片麻岩的岩石成因及元素流动性

Goldschmidt Abstracts Pub Date : 2020-01-01 DOI: 10.46427/gold2020.2477

Haiyan Su, Yican Liu, Yang Yang

引用次数: 0

Pink Axinite from Merelani, Tanzania: a Natural Luminescent Mineral Irradiated in the Neoproterozoic Mozambique Metamorphic Belt 坦桑尼亚Merelani的粉红色辉石:在新元古代莫桑比克变质带辐照的一种天然发光矿物

Goldschmidt Abstracts Pub Date : 2020-01-01 DOI: 10.46427/gold2020.2681

M. Vigier, E. Fritsch

{"title":"Pink Axinite from Merelani, Tanzania:\u0000 a Natural Luminescent Mineral Irradiated in the Neoproterozoic Mozambique Metamorphic Belt","authors":"M. Vigier, E. Fritsch","doi":"10.46427/gold2020.2681","DOIUrl":"https://doi.org/10.46427/gold2020.2681","url":null,"abstract":"Associated with an intense geological event from - 820 to 520 My, East Africa was the place of major metamorphism. It yielded several mineral resources including high-quality gemstones. Those treasures are markers of the geological conditions during their formation. A relatively common mineral -axinite- is found in Merelani (Tanzania) with a rare undocumented pink colour of mysterious origin with an uncommon orange luminescence. We have characterized two extremely rare “pink” axinites from the famous Merelani deposit with classical gemological methods, energy-dispersive analysis on a scanning electron microscope, UV-Visible, Raman and luminescence spectroscopies. We compared the two pink samples to three other crystals from Merelani and one axinite-(Fe) from Oisans (France). Chemical analysis revealed the two pink axinites corresponded to axinite-(Mg). The pink to purple colour is due to a large broad band centred around 550 - 560 nm. Its position and shape are typical for Mn 3+ . Manganese is present in both pink samples as Mn 2+ , and we surmise that radiation from nearby minerals or rocks converted some Mn 2+ into Mn 3+ . The orange luminescence -weaker under shortwave ultraviolet-of the six axinites is related to a broad emission band at 631 nm caused by Mn 2+ and the more unusual red luminescence is associated with two sharp peaks at 688 and 694 nm attributed to Cr 3+ . This unique mineralization expands our knowledge of the impact of local lithology on gemstone colour.","PeriodicalId":12817,"journal":{"name":"Goldschmidt Abstracts","volume":"22 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75848621","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Stable Carbon Isotope Proxies for the Development of Unconventional Petroleum Reservoirs and the Protection of Groundwater Resources 非常规油气开发与地下水资源保护的稳定碳同位素指标

Goldschmidt Abstracts Pub Date : 2020-01-01 DOI: 10.46427/gold2020.347

J. Cesar, J. Wood, P. Humez, M. Nightingale, V. Becker, O. Ardakani, B. Mayer

引用次数: 0

Small-Angle Neutron Scattering Reveals Pressure-Dependent Methane Trapping in Shale 小角中子散射揭示页岩压力依赖性甲烷圈闭

Goldschmidt Abstracts Pub Date : 2020-01-01 DOI: 10.46427/gold2020.1905

Chelsea W. Neil, M. Mehana, R. Hjelm, M. Hawley, Yimin Mao, H. Viswanathan, Q. Kang, Hongwu Xu

引用次数: 0

Deciphering Evolution of Polymetamorphic Terranes: The Western Carpathians Case Study 解读多变质地体的演化:西喀尔巴阡山脉的个案研究

Goldschmidt Abstracts Pub Date : 2020-01-01 DOI: 10.46427/gold2020.2092

D. Plašienka, Š. Méres, Tomáš Potočný