magnetite aggregate

例句：

1. 1. The mineral is used in the production of steel and other metals.
   这种矿物用于生产钢铁和其他金属。
2. 2.The magnetite aggregate has a high magnetic permeability.
   磁铁矿集合体的磁导率很高。
3. 3.The magnetite aggregate is mined from the earth's crust.
   磁铁矿集合体是从地球地壳中开采的。