Which method is used for the concentration of aluminum ore?

Which of the following ores is concentrated using a group $1$ cyanide salt?

In the Serpek process for the purification of bauxite,what is used to remove silicon dioxide?

Haematite ore is concentrated by

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.

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