Mediated extraction of metals from ores

mudasir malik

1. Micelle Mediated Extraction of Metals from Ores

2. Outline Micelle Ore vs Mineral Metallurgy Classification of metals

3. Micelle Micelle Colloidal size particles which exists in equilibrium state with the molecule or ions in the solution from which it is made.

4. Formation of Micelles When the concentration of surfactant is greater than critical micelle concentration (CMC) micelles are formed It depends upon the Krafft temperature

5. Formation of Micelles When the polar head and the non-polar tails arrange in a special way

6. Mineral vs Ore Mineral ore Naturally occurring substance of metal present in the earth crust are called minerals. Minerals which are used to obtain metals are called ores. All minerals are not ores All ores are essentially mineral too Clay is a mineral of Aluminium Bauxite and cryolite are the main ore of Aluminium

7.  EXTRACTION OF METALS (METALLURGY) The process of extracting pure metal from its ore is known as Metallurgy . Steps involved in metallurgy Crushing and grinding Concentration of ore Preliminary treatment of the concentrated ore Reduction Purification

8. CRUSHING AND GRINDING Ore which is obtained from earth crust is in the form of huge lumps. These huge lumps are broken down into small pieces with jaw crushers.

9. Concentration of Ore Extraction of metal from its ore is known as concentration of ore Unwanted rocks are eliminated from ore Purification of Ore Hydraulic washing  Froth Floatation Process  Magnetic Separation  chemical separation

10. Hydraulic washing It is based on gravity differences between the ore and the gangue particles. Lighter gangue particles are washed away by a stream of water, leaving behind the heavier ore.

11. Froth – floating process The powdered ore is treated with an oil detergent mixture, then stirred to create a froth that separates the detergent coated mineral from the gangue.

12. Magnetic separation The powdered ore is rolled on the magnetic roller. Magnetic particles are attracted towards belt leaving behind the non magnetic particles.

13. Chemical separation BAYER'S PROCESS Crude ore is treated with NaOH forming aluminate which on further treatment with HCl produces alumina.

14. PRELIMINARY TREATMENT OF THE CONCENTRATED ORE It consists on two processes Calcination Roasting Calcination Removal of volatile impurities Removal of moisture Decomposition of carbonate ore into oxide

15. Calcination Fe 2 O 3. xH 2 O        →       Fe 2 O 3 +  xH 2 O (g) ZnC0 3             →         ZnO + CO 2   CuC0 3  .Cu(OH) 2         →       2CuO + H 2 O + CO 2

16. Roasting The impurities (sulphur, phosphorus, arsenic) are removed as their oxides Oxidation occurs to form metal oxide and sulphate 2PbS + 3O 2         →                   2PbO + 2SO 2   2ZnS + 30 2         →                   2ZnO + S0 2

17. REDUCTION  Smelting The roasted or calcined ore is mixed with suitable quantity of charcoal   and is heated. Flux + Impurities  →  Slag

18. Purification Purification of impure metals is known as refining . Distillation Volatile metals (zinc and mercury) are purified by this method Liquation   It is used for easily fusible metals (bismuth, tin and lead)

19. Classification of Metals Ferrous - those based on iron Steel Cast iron Non Ferrous - All other metals Precious (Gold, Silver, Platinum etc) Minor (Aluminium, copper, lead etc) Base (Molybdenum, cobalt, Manganese etc)

20. Thanks