Rem-Revista Escola De Minas最新文献_第4页

Petrography and geochronology of the Furquim Quartzite, an eastern extension of the Itacolomi Group (Quadrilátero Ferrífero, Minas Gerais) Itacolomi群东部延伸的Furquim石英岩的岩石学和年代学(Quadrilátero Ferrífero, Minas Gerais)

Rem-Revista Escola De Minas Pub Date : 2015-12-01 DOI: 10.1590/0370-44672015680054

H. Jordt-Evangelista, João Paulo Reis Alvarenga, C. Lana

{"title":"Petrography and geochronology of the Furquim Quartzite, an eastern extension of the Itacolomi Group (Quadrilátero Ferrífero, Minas Gerais)","authors":"H. Jordt-Evangelista, João Paulo Reis Alvarenga, C. Lana","doi":"10.1590/0370-44672015680054","DOIUrl":"https://doi.org/10.1590/0370-44672015680054","url":null,"abstract":"This paper presents the results of a petrographic and geochronological investigation of the Furquim Quartzite (FQ) to establish its stratigraphic correlation to quartzitic units of the Quadrilatero Ferrifero (QF) province. The Quartzite comprises a ca. 20km long and 1-6km wide ridge overlying discordantly the Archean to Paleoproterozoic gneissic basement and rocks of the Archean Rio das Velhas Supergroup between the city Mariana and the town Furquim, southeast of the QF. Despite the discordant contacts, previous field-based stratigraphic studies considered the Furquim Quartzite as part of the Archean Maquine Group – top unit of the Rio das Velhas Supergroup. U-Pb zircon geochronology via LA-ICP-MS identified several detrital populations ranging from Paleoproterozoic to Archean age. The youngest population of 2087±19 Ma defines the maximum age for the sedimentation of the precursor sandstone. This age can be correlated to be the age of the youngest zircon population of the Itacolomi Group quartzites in the QF. Thus, in contrast to previous studies, the results indicate that the FQ is an eastern extension of the Itacolomi Group, the youngest unit of the Paleoproterozoic Minas Supergroup.","PeriodicalId":54498,"journal":{"name":"Rem-Revista Escola De Minas","volume":"2 1","pages":"393-399"},"PeriodicalIF":0.0,"publicationDate":"2015-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88910929","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: 4

Effect of inorganic and organic depressants on the cationic flotation and surface charge of rhodonite-rhodochrosite 无机和有机抑制剂对菱铁矿阳离子浮选和表面电荷的影响

Rem-Revista Escola De Minas Pub Date : 2015-12-01 DOI: 10.1590/0370-44672015680019

R. S. Duarte, R. Lima, V. Leão

{"title":"Effect of inorganic and organic depressants on the cationic flotation and surface charge of rhodonite-rhodochrosite","authors":"R. S. Duarte, R. Lima, V. Leão","doi":"10.1590/0370-44672015680019","DOIUrl":"https://doi.org/10.1590/0370-44672015680019","url":null,"abstract":"Silicates (rhodonite, tephroite, spessartine) and the carbonate (rhodochrosite) of manganese are of economic interest in silicate-carbonated manganese ores. The recovery of both mineral classes by flotation constitutes a challenge; rhodochrosite is a slightly soluble mineral that can release Mn2+ ions in pulp. In this work, the effects of inorganic and organic depressants on the cationic flotation at pH 10 with ether amine acetate and the surface charges of rhodonite and rhodochrosite have been investigated. For rhodonite, the influence of Mn2+ species on its recovery and surface charge at the conditions of maximum yield with amine has also been investigated. The organic depressants, especially the corn starch, were more effective depressants for both minerals. The poor recovery of rhodonite conditioned with MnCl2 is probably related to the colloidal Mn(OH)2 deposition on mineral surface. The increase in the rhodochrosite recovery with increasing water glass content is probably related to its negative value of species adsorbed on the mineral surface, since the rhodochrosite zeta potential, conditioned with this reagent, becomes more negative compared with the mineral without reagent, which attracts the ether ammonium.","PeriodicalId":54498,"journal":{"name":"Rem-Revista Escola De Minas","volume":"74 1","pages":"463-469"},"PeriodicalIF":0.0,"publicationDate":"2015-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86367303","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: 5

Uncommon Nb-tantalate from the Cachoeira mine, Araçuaí pegmatite district (Minas Gerais) 来自Araçuaí (Minas Gerais)伟晶岩区的Cachoeira矿的罕见铌钽酸盐

Rem-Revista Escola De Minas Pub Date : 2015-12-01 DOI: 10.1590/0370-44672014680227

C. H. Dias, M. Chaves

{"title":"Uncommon Nb-tantalate from the Cachoeira mine, Araçuaí pegmatite district (Minas Gerais)","authors":"C. H. Dias, M. Chaves","doi":"10.1590/0370-44672014680227","DOIUrl":"https://doi.org/10.1590/0370-44672014680227","url":null,"abstract":"Important spodumene-rich pegmatites have been mined by CBL (Companhia Brasileira de Litio, Brazilian Lithium Co.) at the Cachoeira mine (northeastern Minas Gerais state) since the 1990's. In this deposit, black platy crystals resembling columbitetantalite are also found; they were analyzed by electronic microprobe as part of the first author's master's degree dissertation. The Cachoeira pegmatite group comprises several spodumene-rich bodies that consist of pertitic microcline, spodumene (on average 23vol%), albite, quartz and muscovite, totalizing more than 95% of the bodies' volume. Analyses on 27 samples of supposedly Nb-tantalates showed a high variation of Ta, Nb and Sn contents, which has been observed inclusive in individual crystals, causing color variation on backscattered electrons images. Surprisingly, analyses on some grains also revealed the presence of ixiolite, a mineral species that has never been described in that region; it is characterized by high SnO2 contents (up to ~16wt%). Columbite-(Fe) phase represents 42% of total Nb-tantalates analyzed samples, tantalite-( Fe) 19%, columbite-(Mn) 3% and ixiolite, 36%. Cassiterite, also observed, shows significant Ta2O5 contents, probably indicating general exsolution processes.","PeriodicalId":54498,"journal":{"name":"Rem-Revista Escola De Minas","volume":"39 1","pages":"401-408"},"PeriodicalIF":0.0,"publicationDate":"2015-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89894939","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

Three-dimensional reconstruction of compacted graphite in vermicular cast iron by manual serial sectioning 用手工连续切片法重建蠕墨铸铁中致密石墨的三维形貌

Rem-Revista Escola De Minas Pub Date : 2015-09-01 DOI: 10.1590/0370-44672014680120

Fernando Almeida Cerqueira, A. S. Nishikawa, W. Guesser, C. Azevedo

引用次数: 3

The influence of tundish heating and purging on inclusion formation 中间包加热和吹扫对夹杂物形成的影响

Rem-Revista Escola De Minas Pub Date : 2015-09-01 DOI: 10.1590/0370-44672014680027

Jayme Alves de Souza Junior, E. A. Vieira, F. Grillo, J. R. Oliveira

{"title":"The influence of tundish heating and purging on inclusion formation","authors":"Jayme Alves de Souza Junior, E. A. Vieira, F. Grillo, J. R. Oliveira","doi":"10.1590/0370-44672014680027","DOIUrl":"https://doi.org/10.1590/0370-44672014680027","url":null,"abstract":"Steel with high cleanliness requirements require an accurate control of the non-metallic inclusions, such as its quantity, morphology, chemical composition and size distribution. The continuous casting tundish has a fundamental role in steel cleanliness, avoiding its reoxidation by air and ladle slag that retain inclusions, as well as aiding the removal of those same inclusions along the continuous casting (Sahai, 2008). To perform the study, IF steel samples were collected in RH at the start, in the middle and at the end of the continuous casting of the tundish's first heat in three different conditions of tundish processing, alternating between heating and purging. These samples had their inclusions characterized by MEV/EDS using the ASCAT (Automated Steel Cleanliness Analysis Tool) technology. The results showed that more than 90% of the oxide inclusions generated in that type of steel are Al2O3 and AlTi. It was also observed that there is an increase of steel inclusions originating from RH in the tundish and that area fraction and average inclusionary density decreases along the continuous casting in two of the processing conditions.","PeriodicalId":54498,"journal":{"name":"Rem-Revista Escola De Minas","volume":"23 1","pages":"301-305"},"PeriodicalIF":0.0,"publicationDate":"2015-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82964857","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

Maps of deformations in a cantilever beam using particle image velocimetry (PIV) and speckle patterns 使用粒子图像测速(PIV)和散斑模式的悬臂梁变形图

Rem-Revista Escola De Minas Pub Date : 2015-09-01 DOI: 10.1590/0370-44672013680016

R. Braga, R. Magalhães, Rafael Pego Melo, J. V. Gomes

{"title":"Maps of deformations in a cantilever beam using particle image velocimetry (PIV) and speckle patterns","authors":"R. Braga, R. Magalhães, Rafael Pego Melo, J. V. Gomes","doi":"10.1590/0370-44672013680016","DOIUrl":"https://doi.org/10.1590/0370-44672013680016","url":null,"abstract":"PIV (particle image velocimetry) has been spreading in studies that use the movement of particles to monitor the displacement of an object or the flow of a fluid by means of velocity vectors using optical techniques and second order statistics. PIV is also known as laser speckle velocimetry when associated with speckle patterns. This technique has been used in works involving fluids, in general, building a map of velocity vectors representing the flow under analysis. This paper presents an approach by using PIV associated to speckle patterns for deformation measurements in a cantilever beam (ASTM A36 steel), one of the most common examples used in civil engineering, without the introduction of external particles. Results showed that the difference between PIV associated to speckle patterns and the analytic displacement values is increased along the beam length for a load of 1.96 N as an evidence of sensitivity of the proposed measurement method. This indicates that PIV is also capable for detecting displacement fields associated with laser speckle patterns in solid mechanics generating a map of deformation as an additional option for non-destructive tests.","PeriodicalId":54498,"journal":{"name":"Rem-Revista Escola De Minas","volume":"30 1","pages":"273-278"},"PeriodicalIF":0.0,"publicationDate":"2015-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90096320","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: 6

Influence of growth ring orientation of some wood species to obtain toughness 生长环取向对某些木材获得韧性的影响

Rem-Revista Escola De Minas Pub Date : 2015-09-01 DOI: 10.1590/0370-44672014680018

D. O. Stolf, M. S. Bertolini, D. H. D. Almeida, D. A. L. Silva, T. Panzera, A. Christoforo, F. Lahr

引用次数: 9

Influence of Mn2+ ion in reverse cationic flotation of iron ore Mn2+离子对铁矿石反阳离子浮选的影响

Rem-Revista Escola De Minas Pub Date : 2015-09-01 DOI: 10.1590/0370-44672015680051

D. Cruz, R. Lima

引用次数: 3

Processes for phosphorus removal from iron ore - a review 铁矿石除磷工艺研究进展

Rem-Revista Escola De Minas Pub Date : 2015-09-01 DOI: 10.1590/0370-44672014680202

A. C. Pereira, R. M. Papini

引用次数: 15

Iso-velocity maps. A vibration control tool in quarries Iso-velocity地图。采石场振动控制工具

Rem-Revista Escola De Minas Pub Date : 2015-09-01 DOI: 10.1590/0370-44672014680163

Giselle Ramirez Canedo, S. Eston, W. Iramina, Michiel Wichers Schrage

{"title":"Iso-velocity maps. A vibration control tool in quarries","authors":"Giselle Ramirez Canedo, S. Eston, W. Iramina, Michiel Wichers Schrage","doi":"10.1590/0370-44672014680163","DOIUrl":"https://doi.org/10.1590/0370-44672014680163","url":null,"abstract":"Urban growth around mining areas has brought problems such as neighborhood's discomfort due to blasting vibrations, which can cause structural damage to the houses, dust and atmospheric overpressure. In Brazil, environmental restrictions are increasingly rigorous and seismic monitoring is required as an environmental control measure. This study aims to analyze a methodology for application of iso-velocity maps in quarries located in urban areas and evaluate options for building iso-velocity maps. This work was performed in a quarry located in the State of Sao Paulo and four blastings were monitored. All blastings had similar features and they were evaluated in the same bench. For each equation, directional, scaled-distance parameters were estimated and different iso-velocity maps were made and compared. It is concluded that geophone disposition must adjust to the monitoring purposes. Eight to fifteen aligned geophones are adequate for a scaled-distance curve. Sixty-four or more geophones, spatially and homogeneously distributed, can generate an iso-velocity map concerning a single blasting. High variability of rock mass features seems to prevent obtaining good results when the seismographs are not homogeneously distributed surrounding the blasting.","PeriodicalId":54498,"journal":{"name":"Rem-Revista Escola De Minas","volume":"45 1","pages":"313-318"},"PeriodicalIF":0.0,"publicationDate":"2015-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90515274","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: 1