Which of the following ores are concentrated by froth floatation?

Which of the following ores are concentarted by froth floatation?

Which of the following ores can be concentrated by froth floatation method and why? Fe_2O_3, ZnS, Al_2O_3

(a) Which of the following ores can be concentrated by froth floatation method and why? Fe_2O_3,ZnS,andAl_2O_3 (b) What is the role of silica in the metallurgy of Copper?

Which of the following ores can be concentrated by froth-floatation process ? ( Fe_2O_3 , AI_2O_3 , ZnS)

Which of the following ores can be concentrated by froth-floatation process ? ( Fe_2O_3 , AI_2O_3 , ZnS)

Which of the following ores is not concentrated by froth floatation process?