Mineral Processing (Pyrometallurgy)

Class Presentation on Basics of Pyrometallurgy

1. University Of Liberia College of Engineering Department of Mining engineering Mineral Processing II PYROMETALLURGY Presented by: Abraham Habibi Barry 70800 Presented to: Mr. Nathaniel Johnson Monday, July 24, 17 Mineral Processing II Pyro-Metallurgy By: Abraham H. Barry 1

2. Pyrometallurgy Presentation Content: What Is Pyrometallurgy Processes Of Pyrometallurgy Calcination Roasting Smelting Refining Furnaces used in Pyrometallurgy Conclusion References Q & A Monday, July 24, 17 Mineral Processing II Pyro-Metallurgy By: Abraham H. Barry 2

3. Pyrometallurgy What Is Pyrometallurgy? It is a branch of Extractive Metallurgy It Uses Thermal Energy to achieve separation Its products may be: Pure Metal Intermediate Compound Alloys Mineral Processing II Pyro-Metallurgy By: Abraham H. Barry 3 Monday, July 24, 17

4. Pyrometallurgy Processes Of Pyrometallurgy: Calcination A thermal treatment process done sometimes in the absence of oxygen Calcining Causes: T hermal decomposition P hase transition R emoval of a volatile fraction The calcination process normally takes place at temperatures below the melting point of the product materials . Used mostly for Carbonate Ores. Mineral Processing II Pyro-Metallurgy By: Abraham H. Barry 4 Monday, July 24, 17

5. Pyrometallurgy Processes Of Pyrometallurgy: Roasting A process of heating of sulphide ore to a high temperature in presence of air. Ores subjected to roasting are purified by froth flotation. Roasting is a complex separation technique of thermal gas–liquid reactions. They include: oxidation reduction Chlorination Sulfation pyrohydrolysis Mineral Processing II Pyro-Metallurgy By: Abraham H. Barry 5 Monday, July 24, 17

6. Pyrometallurgy Types of Roasting: Oxidizing Roasting Most Commonly practiced form of Roasting General Equation: 2 MS (s) + 3MO 2 (g) = 2MO 2 (s) + 2SO 2 (g) Volatizing Roasting I nvolves careful oxidation at elevated temperatures of the ores, to eliminate i mpurity in the form of their volatile oxides . Mineral Processing II Pyro-Metallurgy By: Abraham H. Barry 6 Monday, July 24, 17

7. Pyrometallurgy Types of Roasting: Chloridizing R oasting T ransforms certain metal compounds to chlorides General Equations: 2NaCl + MS + 2O 2 = Na 2 SO 4 + MCl 4NaCl + 2MO + S 2 + 3O 2 = 2Na 2 SO 4 + 2MCl 2 Mineral Processing II Pyro-Metallurgy By: Abraham H. Barry 7 Monday, July 24, 17

8. Pyrometallurgy Types of Roasting: Sulfating roasting Oxidizes sulfide ores to sulfates in a controlled supply of air to enable leaching of the sulfate Magnetic roasting controlled roasting of the ore to convert it into a magnetic form R eduction of hematite (non magnetic Fe 2 O 3 ) to magnetite (magnetic Fe 3 O 4 ) Reduction roasting Sinter roasting simultaneous oxidation and agglomeration of the ores. Mineral Processing II Pyro-Metallurgy By: Abraham H. Barry 8 Monday, July 24, 17

9. Pyrometallurgy Processes Of Pyrometallurgy: Smelting process by which a metal is obtained, either as the element or as a simple compound by heating beyond the melting point . Smelting is done in the presence of: Oxidizing agents = A ir Reducing agents = Coke Mineral Processing II Pyro-Metallurgy By: Abraham H. Barry 9 Monday, July 24, 17

10. Pyrometallurgy Processes Of Pyrometallurgy: Refining Purification of an impure metal. Different from smelting and calcining in that: They involve a chemical change to the raw material, while in refining, the final material is usually identical chemically to the original one, only it is purer. Mineral Processing II Pyro-Metallurgy By: Abraham H. Barry 10 Monday, July 24, 17

11. Pyrometallurgy Types of Furnaces: Shaft Furnace These are vertical furnaces with the charge added at the top and removed at the bottom, while gas is blown into the bottom and exits the top. Mineral Processing II Pyro-Metallurgy By: Abraham H. Barry 11 Monday, July 24, 17

12. Pyrometallurgy Types of Furnaces: Blast Furnace A type of shaft furnace in which a blast of preheated air is blown in through tuyeres at the bottom. Mineral Processing II Pyro-Metallurgy By: Abraham H. Barry 12 Monday, July 24, 17

13. Pyrometallurgy Types of Furnaces: Muffle Furnace This type of furnace is used when the material being heated should not be contaminated by the heating fuel. Mineral Processing II Pyro-Metallurgy By: Abraham H. Barry 13 Monday, July 24, 17

14. Pyrometallurgy Types of Furnaces Hearth Furnace Hearth furnaces allow the burning fuel to come in contact with the material being heated. This allows very high temperatures to be reached Mineral Processing II Pyro-Metallurgy By: Abraham H. Barry 14 Monday, July 24, 17

15. Pyrometallurgy Conclusion: Pyrometallurgy was one of the primary method of separation discovered. Uses the thermodynamic properties of ores to drive chemical and physical reactions. It consumes tremendous amount of energy. Causes pollution if not managed extremely carefully. Pyrometallurgy is useful in metal separation and alloy production. Mineral Processing II Pyro-Metallurgy By: Abraham H. Barry 15 Monday, July 24, 17

16. Pyrometallurgy References: H S Ray, R Sridhar and K.P Abraham; extraction of non ferrous metals . Pyrometallurgy basics, assessed at http://www.carbolite-gero.com/ applications/heating-applications calcination/ on July 23, 2017. Primary Metal Production assessed at http://www.chem.mtu.edu/ chem_eng/faculty/kawatra/CM2200_Primary_Metals on July 23, 2017. Mineral Processing II Pyro-Metallurgy By: Abraham H. Barry 16 Monday, July 24, 17

17. Pyrometallurgy Thank You Mineral Processing II Pyro-Metallurgy By: Abraham H. Barry 17 Monday, July 24, 17

18. Pyrometallurgy Questions & Answers Mineral Processing II Pyro-Metallurgy By: Abraham H. Barry 18 Monday, July 24, 17