Vivianite and siderite in lateritic iron crust: an example of bioreduction

Quimica nova

Faria, Mario Sergio Gomes de¹  Lemos, Vanda Porpino²  Lemos, Ronaldo Lima²  Costa, Marcondes Lima da² 

[1] Companhia de Pesquisa de Recursos Minerais, Manaus, Brasil;Universidade Federal do Pará, Belém, Brasil

关键词: bioreduction;    siderite;    vivianite.;   

DOI  :  10.1590/S0100-40422007000100008

学科分类：化学（综合）

来源: Sociedade Brasileira de Quimica

【 摘 要 】

Lateritic ironcrust (LIC) samples from Padauari (AM) were analysed by XRD, optical microscopyand SEM-EDS. The equilibrium of iron minerals (IM) was studied using Eh-pH diagram.It was shown that the minerals of the LIC are goethite (a-FeOOH),vivianite [Fe3(PO4)2.8H2O] and siderite(FeCO3). Carbonate grains are a solid solution of FeCO3-MnCO3.The LIC presents textures and structures of dissolution of IM. The sideriteand vivianite are stable from Eh =-0.3 to 0.0 V and pH=5.0-7.5. These resultsindicate that vivianite and siderite are products of bioreduction through biogenicdissolution of IM, the new conditions of ecosystems of the Amazon region.

【 授权许可】

CC BY