Question

extraction of mercury from its ores cinnator with chemical reation

Answer 1

1. Concentration

Cinnabar being sulphide is is concentrate by froth floatation method. The pulverized are is kept in water containing pine oil & the mixture is agitated by passing compressed air. Ore forms froth with oil and come to the surface and are skimmed off while impurities are left in water.

 

2. Roasting and Distillation

The concentrated are is mixed with 2% coke and fed into shaft furnace through a cup and wne. Arrangement the furnace is heated by pruning fuel and air is below in cinnabar is first oxidized to mercuric oxide which then decompose into mercury the vapor of mercury are condensed in Y-shaped. Earthen condensers cooled by water.

           

2HgS + O2                  →            2HgO + 2SO2

            2HgO                    →                  2Hg + O2

 

3. Purification:-

Mercury obtained by above process is not pure and contains impurities like copper (Cu), Zn, Bi, Ag, etc. as impurities. The impure mercury is filtered through daemons leather to remove suspended soiled. After that mercury is dropped through a long tube filled with 5% HNO3 solution. The base metals dissolve in HNO3 as Nitrate.

            4Zn + 10 HNO3       →               4Zn(NO3)2 + NH4NO3 + 3H2O

            4Cu+ 10 HNO3           →            4Cu(NO3)2 + 2NO + 4H2O

 

Any mercurous nitrate if from reacts with base metal giving back mercury.

           

Hg2(NO3)2 + Cu       →               Cu (NO3)2 + 2Hg

 

 

 

Mercury still contains metal like gold (Au), silver (Ag), Pt, etc. as impurities. These are removed by vacuum distillation where mercury distills leaving other metals.