Isothermal Enriching Perovskite Phase from CaO–TiO₂–SiO₂–Al₂O₃–MgO Melt by Super Gravity

摘要

A new approach to enriching perovskite phase from CaO–TiO_(2)–SiO_(2)–Al_(2)O_(3)–MgO melt by super gravity was investigated. The samples obtained by the gravity coefficient G≥600, time t≥20 min and temperature T≥1578 K appear significant layers and perovskite phase present gradient size distribution in the sample along the super gravity. The layered sample was central cut and characterized by metallographic microscopy, and it is hardly to find any perovskite particles in the upper area of the sample and the perovskite phase gathers at the middle and bottom areas of the sample. The mechanism of moving speed of perovskite particles in super gravity field was also discussed, and the conclusion indicates that the moving speed of perovskite particles is proportional to the square of the perovskite particle size. As a result, large size perovskite particles move a farther distance than the small ones and gather at the bottom of the sample, while small size perovskite particles accumulate in the middle of the sample. Under the hypothesis that the titanium exists in the slag in terms of TiO_(2), with the gravity coefficient G=600, time t=20 min and temperature T=1578 K, the mass fraction of TiO_(2) in the concentrate is up to 34.97%, while that of the tailing is just 11.16%. Considering that the mass fraction of TiO_(2) is 22.34% in the parallel sample, the recovery ratio of Ti in the concentrate is up to 74.16% by centrifugal enrichment.