What are the various methods used for the concentration of an ore?

Which of the following ores is best concentrated by the froth-flotation method?

In the leaching method,bauxite ore is digested with a concentrated solution of $NaOH$ that produces $X$. When $CO_2$ gas is passed through the aqueous solution of $X$,a hydrated compound $Y$ is precipitated. $X$ and $Y$ respectively are

The froth floatation process used for the concentration of sulphide ore:

Which of the following ores is most commonly concentrated by the froth flotation process?

The complex formed when $Al_2O_3$ is leached from Bauxite using concentrated $NaOH$ solution is,