Explain the role of each of the following:
(i) NaCN in the extraction of silver
(ii) SiO2 in the extraction of copper
(i) Name the method of refining of metals such as Germanium.
(ii)In the extraction of Al, impure Al2O3 is dissolved in conc. NaOH to form sodium aluminate and leaving impurities behind. What is the name of this process?
(iii)What is the role of coke in the extraction of iron from its oxides?
Describe the principle controlling each of the following processes:
(i) Preparation of cast iron form pig iron.
(ii) Preparation of pure alumina (Al2O3) from bauxite ore.Explain the principle of the method of electrolytic refining of metals. Give one example.
Out of PbS and PbCO3 (ores of lead), which one is concentrated by froth flotation process preferably?
Leaching is significant as it helps in removing impurities like SiO2, Fe2O3 etc. It is the chemical method used for the concentration of ores. Aluminum is generally extracted from bauxite ore, this ore contains SiO2, iron oxides, and titanium oxide as impurities. It is concentrated by digesting the powdered ore with a concentrated solution of NaOH at 473-523 K and 35-36 bar pressure when Al2O3 gets leached out as sodium aluminate. The impurities are left behind.
Write the chemical reactions involved in the process of extraction of Gold. Explain the role of dilute NaCN and Zn in this process