Two Co-rich seamount crust reference materials, MCPt-1 and MCPt-2, were prepared using ultra-fine particle size milling technique and characterised for the platinum-group elements (PGEs). The raw material for these two reference materials was collected separately from the Magellan seamounts of the western Pacific Ocean and the seamounts of the central Pacific Ocean by Russian and Chinese scientists. First, they were ground by ball mill to a −200 mesh powder, then further processed by ultra-fine jet mill and well-mixed. The particle size distributions of the samples were tested by a laser particle analyser; the average particle size was 1.8 and 1.5 μm (equal to about 2000 mesh) respectively. The homogeneity of six major and minor elements in these two materials was tested at the milligram level of sampling mass by high-precision wavelength dispersive X-ray fluorescence (XRF) spectrometry and at the microgram level of sampling mass by electron probe microanalyser. The homogeneity of more than forty trace elements, including Pt, was tested at the microgram level of sampling mass by LA-ICP-MS. Except for Rh, all PGEs were determined by isotope dilution-ICP-MS. Platinum in MCPt-1 and MCPt-2 was characterised as certified values, whereas the other five PGEs in MCPt-1 and MCPt-2 were reported as reference values. In addition, the information values of sixty-two major, minor and trace elements were obtained by XRF, ICP-AES and ICP-MS. The minimum sampling mass for the determination of PGEs was 1 g, while the minimum sampling mass for the determination of the other elements was 2–5 mg.



Deux materiaux de reference riches en Co provenant de la partie crustale de monts sous-marins, MCPt-1 et MCPt-2, ont ete prepares en utilisant des techniques de broyage ultrafin et caracterise pour les elements du groupe du platine (PGE). Les matieres premieres pour ces deux materiaux de reference ont ete recueillies separement au niveau des monts sous-marins de Magellan situes dans l’ocean Pacifique ouest et des monts sous-marins de l’ocean Pacifique central par des scientifiques Russes et Chinois. Ils ont ete d’abord broyes avec un broyeur a billes pour obtenir une poudre de −200 mesh (74 μm), puis traites par un broyeur ultrafin a jet d’air et bien melange. Les distributions granulometriques des echantillons ont ete testees par un analyseur de particules a laser, la taille moyenne des particules est respectivement de 1.8 μm et 1.5 μm (egale a environ 2000 mesh). L’homogeneite de six elements majeurs et mineurs dans ces deux materiaux a ete testee a l’echelle du mg d’echantillon en utilisant un spectrometre de fluorescence X a dispersion de longueur d’onde de haute precision et a l’echelle du μg de masse d’echantillon par microsonde sonde electronique. L’homogeneite de plus de quarante elements traces, y compris Pt, a ete testee a l’echelle du μg de masse d’echantillon par LA-ICP-MS. A part le Rh, tous les PGE ont ete determinees par dilution isotopique ICP-MS. Le platine a ete caracterise dans MCPt-1 et MCPt-2 comme valeurs certifiees, alors que les cinq autres PGE l’ont ete comme valeurs de reference. En outre, les valeurs informatives de soixante-deux elements majeurs, mineurs et traces ont ete obtenus par XRF, ICP-AES et ICP-MS. La masse minimale d’echantillon pour la determination des PGE est de 1 g, tandis que la masse minimale d’echantillon pour la determination des autres elements est de 2–5 mg.

Platinum-Group Element Results for Two Cobalt-Rich Seamount Crust Ultra-Fine Reference Materials: MCPt-1and MCPt-2

The flow field in the chamber of a fluidized bed op-posed superfine jet mill was numerically simulated by standard k-e turbulent model and SIMPLEC algorithm based on CFD. Path lines in the chamber of the mill, grinding region and classifying region were plotted using the predicted results. Velocity fields in grinding region and classifying region of the mill were presented in the paper. Velocity profiles at different height section along diameter were analyzed. Flow field in the chamber of the mill was measured by 5-hole probe testing system. The simulation results agree well with the experiment results. Numerical simulation technology combined with flow testing measured could promote the optimization design for the fluidized bed opposed superfine jet mill.

Study on the Flow Field in the Chamber of a Fluidized Bed Opposed Superfine Jet Mill

The working principle and advantages of fluidized bed counter-jet mill were introduced.The recents research of key technology of fluidized bed mill,such as nozzle,comminution,classification,were reviewed.It's shown that the best working state of fluidized commter-jet mill can be achieved by improving on and optimizing key parts and the quality and quantity of products can be improued.

Cai Dong-mei

Papers

Key Technology of Fluidized Bed Counter-jet Mill and Its Progress