The function of potassium ethyl xanthate in the froth floatation process is to make the ore

Observe the following statements regarding the purification of bauxite and select the correct answer.
$(I)$ During the $Hall$ process,silicon is removed in the form of vapor.
$(II)$ Bauxite containing $Fe_2O_3$ impurities is purified by the $Bayer$ process.
$(III)$ $AlN$ is formed during the $Serpeck$ process.

Why is the concentration of ore performed?

Explain the froth flotation process.

Which one of the following ores is best concentrated by froth floatation method?

Which of the following is not concentrated by electromagnetic separation?