ABSTRACT
The regional features, metallogenitic regularities and mineral composition of the hydrothermal sulphide ore have been preliminarily studied. According to the different mineralization period, the patterns of valuable minerals disseminated in ore are complicated, which causes the large changes in the properties of the sulphide ore. The different properties of the sulphide ore may increase the difficulty of the mineral processing and reduce the recovery rate of valuable minerals. Therefore a simple method for rapidly classification of sulphide ore is required to optimize mineral processing flowsheet. Laser Raman spectrometry, as an effective method to analyze the structure of the material is used to identify the component and structure of minerals. The research on the Laser Raman spectra of the large number of sulphide ore samples can reveal the reasons for the difference of the Raman spectra. A new method for classifying the complex sulphide ore using Raman spectroscopy is proposed. The experiment results demonstrate that the properties of the sulphide ore in different mineralization period vary greatly and the fluorescent scattering is mainly produced by gangue minerals. The measured Raman spectral after quenching the fluorescence scattering show the peaks of Raman spectra at 201.62, 242.54, 288.38 and 309.77 cm-1 can be used to identify this kind of complex sulphide ore. The raw ore can be divided into three categories based on the difference of the intensity of fluorescence scattering and the ratio of fluorescence and Raman intensity. The accuracy of the classification method is further validated by the industrial tests. The findings demonstrate the close relationship between Raman spectra and the properties of sulphide ore. The proposed method, which can fast classify the sulphide ore, don't need complex chemical pretreatment before spectra collection. Therefore, this method will have important application value for improving the efficiency of mineral processing.
ABSTRACT
OBJECTIVE: To observe the long-term impact of calcium phosphate (CaP) sol-gel coating on bone growth around porous-surfaced implant. METHODS: The porous-surfaced Ti-6Al-4V implants were prepared with the addition of a thin film of CaP sol-gel coating, and implanted into the tibiae of 8 rabbits, each with two implants. Implanted sites were allowed to heal for 2, 8, 12, and 24 weeks, after which specimens were obtained for scanning electron microscope analysis using the freeze-fracture technique. RESULTS: The sol-gel coated implants recovered by freeze-fracture technique showed extensive bone growth from the endosteum along the implant surface. The bone was in direct contact with the CaP layer. The cement line-like layer was clearly demonstrated to be an intervening electron dense afibrillar layer between the CaP coat and the overlying newly deposited bone. The stability and osseointegration of the porous-surfaced implants seemed not to be affected by the osteoclastic resorption of CaP layer occurred during 24 weeks of healing. CONCLUSION: Based on the findings in the long-term observation, the addition of a thin layer of CaP promotes an extensive osseointegrated interface between the porous-surfaced Ti-6Al-4V implants and the newly deposited bone.
