DIGITAL ALBUM

DIGITAL ALBUM

Submitted by GREESHMA BABU 18220368008 B Ed PHYSICAL SCIENCE KAVIYATTU COLLEGE OF EDUCATION

METALLURGY

Metallurgy is defined as a process that is used for the extraction of metals in their pure form.

STEPS INVOLVED IN THE EXTRACTION OF METALS FROM THEIR ORES ARE: 1. Crushing and pulverization 2. Concentration or dressing of the ore 3. Calcination or roasting of the ore 4. Reduction of metal oxides to free metal 5. Purification and refining of metal

1. CRUSHING AND PULVERISATION The first process in metallurgy is crushing of ores into a fine powder in a crusher or ball mill. This process is known as pulverisation.

2. CONCENTRATION OF ORES The process of removing impurities from ore is known as concentration or ore dressing.

STEPS INVOLVED IN THE CONCENTRATION OF ORES  Hydraulic washing  Magnetic separation  Froth floatation  Leaching

 HYDRAULIC WASHING This method concentrates the ore by passing it through an upward stream of water whereby all the lighter particles of gangue are separated from the heavier metal ore. This is a type of gravity separation.

 MAGNETIC SEPARATION This involves the use of magnetic properties of either the ore or the gangue to separate them. The ore is first ground to fine pieces and then passed on a conveyor belt passing over a magnetic roller. The magnetic ore remains on the belt and the gangue falls off the belt.

 FROTH FLOTATION This method is mainly used to remove gangue from sulphide ores. The ore is powdered and a suspension is created in water. To this collectors and froth stabilizers are added. The oil wets the metal and the water wets the gangue. The frothy meatal is skimmed off the top and dried to recover the metal.

 LEACHING It is a chemical process of concentration of ore. Here the ore dissolves in a chemical solution. The minerals will react and dissolve leaving behind impurities only which filter out. And then the metal will be obtained from the chemical solution.

PURIFICATION AND REFINING OF METAL The process of purifying impure metal is called refining of metal. Methods that can be used for refining metals are: • Distillation • Liquation • Zone refining

• DISTILLATION

• LIQUATION

• ZONE REFINING

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