【摘要】 在对湖南湘潭锰矿次生氧化带中天然锰钾矿鉴定的基础上,采用HRTEM对该地区结晶程度差、呈隐晶质集合体的天然锰钾矿微结构进行研究,结果表明:M n,K,O为样品的主要元素,还含少量Cu,S i,A l,M g,F e等杂质元素;锰钾矿表现出一维针状的纳米晶,大多数纳米晶的宽度<100 nm;对选区电子衍射(SAED)计算d值并指标化,确定是锰钾矿,而电子衍射所表现出的弥散环、衍射斑点圆弧化和拉长,均表明该地区样品结晶度差、具有超结构和一定择优取向的特征,这与锰钾矿呈一维针状纳米晶的特征相一致。在锰钾矿的晶格像中,普遍存在晶格畸变、位错缺陷和超结构现象。因此,结晶度较差、颗粒细小至纳米级、结构的有序度较低等是该地区锰钾矿的主要特点。更多还原

【Abstract】 As oxide octahedral molecular sieve(OMS-2),cryptomelane has been paid more attention to the aspect of the purification of environment.In order to provide some useful information,this paper mainly use HRTEM to study the characters of microstructure of natural cryptomelane in the supergene oxide ore of Xiangtan Manganese Deposit,Hunan Province which exhibit poor crystallographic degree and hidden fine-grained aggregations on appearance.The study indicated that major elements are Mn,K,O,and impurity elements are Cu,Si,Al,Mg,Fe in sample.The observation of TEM indicates nano-grade crystal particles of one dimension needles exist,which agree with monoclinic crystallographic habits of cryptomelane.They gather along b axis with width of less than 100 nm.It is confirmed as cryptomelane again by calculating d value and indexing for SAED.The SAED patterns manifest poor crystallographic degree and super-microstructure existence because most of them show dispersed loops and arc of spots.Distortion of crystal lattice,dislocation(edge) defects,and superstructures exist in crystal lattice images of cryptomelane.Therefore,the cryptomelane is characteristic of poorer degree of crystallography,fine-grained particles,and lower ordered structure.更多还原