niobite

a hard gray lustrous metallic element that is highly corrosion-resistant; occurs in niobite and fergusonite and tantalite.

一种坚硬有的灰色金属元素，抗腐蚀性极强，见于铌铁矿、褐钇铌矿和钽铁矿中。

The major metal minerals recycled include tantalum niobite, fine spar, tantalum aeschynite, wolframite and scheelite, which have large density of generally 5 to 7.

要回收的金属矿物钽铌铁矿、细晶石、钽易解石、黑钨矿、白钨矿，密度，一般为5~7。