如何研究变生矿物

原生晶质矿物,由于含有一定剂量的放射性元素铀或钍,使矿物内部的晶格遭受破坏转变成非晶质,而仍然保持其晶体的外形,这种矿物称变生矿物(蜕晶质矿物)。变生矿物的特征:矿物由品质转变为非品质,引起矿物的物理性质的改变。表现明显的是矿物的颜色变深而不均匀,光泽减弱,密度变小,折光率变低,解理消失。

青岛海滩砂中的变生矿物曲晶石

青岛海滩砂中的曲晶石(Cyrtolite)晶形完好，除了具有锆石的一般性质外，以富含Th、Y、Yb、Hf、La、Re和Sc等稀有、稀土、放射性元素为特征，是青岛海滩重矿物砂中的重要稀土元素矿物之一。

我国稀土铌钽矿物学研究回顾与展望

作为高新技术原料用的稀土铌钽是国家发展的支柱之一 ,稀土铌钽矿物学研究在与国家的技术进步同步前进。通过研究 ,已经获得了我国产出的全部百余种稀土铌钽矿物的化学组成、物理性质、稀土配分、结晶参数、共生组合和产状成因的全面系统的鉴定描述成果 ;发现了多种稀土铌钽新矿物 ,并提出许多新规律和新理论 ,建立了易解石和褐钇铌矿两个新的矿物族 ;确定了稀土铌钽铁锰钨的复杂氧化物的晶体结构关系 ;确立变生矿物学为矿物学研究的一个特殊分支 ,探讨了稀土次生富集的离子型稀土矿成矿机理。

Formation and evolution of secondary minerals during bioleaching of chalcopyrite by thermoacidophilic Archaea Acidianus manzaensis

The formation and evolution of secondary minerals during bioleaching of chalcopyrite by thermoacidophilic Archaea Acidianus manzaensis were analyzed by combining synchrotron radiation X-ray diffraction（SR-XRD） and S, Fe and Cu Kα X-ray absorption near edge structure（XANES） spectroscopy. Leaching experiment showed that 82.4% of Cu2＋ was dissolved by A. manzaensis after 10 d. The surface of chalcopyrite was corroded apparently and covered with leaching products. During bioleaching, the formation and evolution of secondary minerals were as follows： 1） little elemental sulfur, jarosite, bornite and chalcocite were found at days 2 and 4; and 2） bornite and chalcocite disappeared, covellite formed, and jarosite gradually became the main component at days 6 and 10. These results indicated that metal-deficiency sulfides chalcocite and bornite were first formed with a low redox potential value（360-461 m V）, and then gradually transformed to covellite with a high redox potential value（461-531 m V）.

Effects of mutation on a new strain Leptospirillum ferriphilum YXW and bioleaching of gold ore

Leptospirillum ferriphilum YXW was isolated through serial dilution from mixed microorganisms enriched in AMD from Dexing copper mine in Jiangxi Province, China. It was mutated by ultrasonic, UV and microwave to collect more efficient strain for bioleaching of gold ore. Physiological and biochemical characteristics indicate that strain YXW is a strict chemoautotrophic microorganism, and the optimal condition for its growth is temperature of 40 °C and pH 1.5. After mutation by ultrasonic, UV and microwave, the density of bacterial cells reached 9×109, 8.4×109 and 4.3×108 mL-1, increased by 291%, 265%and 87%, respectively, compared with the original culture. The bacterial total protein activity was improved by microwave and UV mutations, but was reduced by ultrasonic. Mutations had effects on bioleaching of gold ore in sequence of microwave〉UV〉ultrasonic. During gold ore bioleaching, the bacterial mutant after mutation by microwave had the best effect on the extraction rates of arsenic and iron, which were 19.6%and 17.7%higher than that of the original strain after bioleaching for 10 d, respectively. The results suggested that the effects of mutation on bioleaching of gold ore may not be mainly due to increase of bacterial cells density, but may be mainly attributed to the improvement of bacterial total protein activity.

Effect of temperature-induced phase transitions on bioleaching of chalcopyrite

The phase transformation of chalcopyrite and the effect of its phase status on bacterial leaching were studied. Under the protection of high-purity argon, different temperatures(203, 382 and 552℃) were applied to natural chalcopyrite to complete the phase change. In addition, the chalcopyrite was bioleached before and after the phase change. The results show that the chalcopyrite heated at 203 and 382℃ remained in the α phase, whereas the chalcopyrite changed from α to β phase at 552℃. The leaching rates of chalcopyrite after the phase transitions at 203, 382 and 552℃ were 32.9%, 40.5% and 60.95%, respectively. Further, the crystal lattice parameters of chalcopyrite increased and lattice energy decreased, which were the fundamental reasons for the significant increase in leaching rate. Electrochemical experiments demonstrated that with increasing annealing temperature, the polarization resistance decreased and corrosion current density increased. The higher the oxidation rate was, the higher the leaching rate was.

Bioleaching of chalcocite by mixed microorganisms subjected to mutation

Mixed microorganisms with elevated activity of chalcocite-leaching were screened by mutation methods. The original microorganisms collected from acid mine drainage of different sites were mixed and then treated with mutagens NO2^- , diethyl sulfate （DES）, UV and their combinations, respectively. Five groups of mixed microorganisms with much stronger ore-leaching ability were obtained by screening on the leaching media. Among them, group E of mixed microorganisms （treated with 1% DES for 60 min） with the best perfonnance on chalcocite-leaching, increases the content of Cu^2＋ by 101.4% in 20 d of leaching compared with the control culture. In addition, group E is more tolerant to Cu^2＋ in media than the control without mutation treatment. Analysis for the diversity of microbial clones indicates that half of operational taxonomic units （OTUs） in group E are Acidithiobacillus ferrooxidans. These observations suggest that group E might have potentials for industrial application.

Annual Component Analysis of Pacific Oysters （Crassostrea gigas） and Mussels （Mytilus gallopro vincialis）

To study the change in components of Pacific oysters （Crassostrea gigas） and mussels （Mytilus galloprovincialis） over a year, their annual obesity ratio, umami components （glutamic acid and glycogen）, functional components （Zn, Mn, Cu, and vitamin B12）, and Cd and noroviruses （NoVs） contents were quantified. In oysters, the obesity ratio and chemical components showed seasonal changes depending on the spawning season. Glutamic acid content increased from November to March. In contrast, glycogen content peaked in May and November. Mineral content markedly increased during spawning. From the comparison of NoVs GI and GII strains, oyster predominately infected by the GI. A remarkable difference in NoVs contents was observed depending on the oyster farms. In mussels, glutamic acid, Zn and Cu contents were stable throughout the year. Mussels＇ Cd content was about one-fifths times lower than that found in oysters. Although the NoVs strain was affected by the collection area, mussels from both areas showed decreased NoVs contents in summer, corresponding with the consumption season of mussels in Japan. Our comparative study on the seasonal variability in the chemical components and NoVs contents in pacific oysters （C. gigas） and mussels （M. galloprovincialis） clearly showed an association with physiological and environmental factors.