Metal and Metallurgy

This is the part of my college Project work :

1 INTRODUCTION

A metal (Greek: Metallon) is an element that readily forms ions (cations) and has metallic bonds, and it is sometimes said that it is similar to a cation in a cloud of electrons. The metals are one of the three groups of elements as distinguished by their ionization and bonding properties, along with the metalloids and nonmetals. On the periodic table, a diagonal line drawn from Boron (B) to Polonium (Po) separates the metals from the nonmetals. Elements on this line are metalloids, sometimes called semi-metals; elements to the lower left are metals;

Physical Character

Metals have certain characteristic physical properties: they are usually shiny (they have "lustre"), have a high density, are ductile and malleable, usually have a high melting point, are usually hard, and conduct electricity and heat well. These properties are mainly because each atom exerts only a loose hold on its outermost electrons (valence electrons); thus, the valence electrons form a sort of sea around the metal ions. Most metals are chemically stable, with the notable exception of the alkali metals and alkaline earth metals, found in the leftmost two groups of the periodic table.
Mineral processing, otherwise known as mineral dressing, is the practice of beneficiating valuable minerals from their ores. Industrial mineral treatment processes usually combine a number of unit operations in order to liberate, concentrate and classify minerals using physical properties and processes.
Many plants will also incorporate hydrometallurgical or pyrometallurgical processes as part of an extractive metallurgical operation. Mineral processing involves manipulating particle size by crushing and grinding the ore. Combined with particle size classification unit operations, this area is often termed comminution





2 Metallurgy

Metallurgy is a domain of materials science that studies the physical and chemical behavior of metallic elements, their intermetallic compounds, and their compounds, which are called alloys. It is also the technology of metals: the way in which science is applied to their practical use. The term is nowadays distinguished from the craft of metalworking.


Extractive metallurgy

Extractive metallurgy is the practice of removing valuable metals from an ore and refining the extracted raw metals into a purer form. In order to convert a metal oxide or sulfide to a purer metal, the ore must be reduced either physically, chemically, or electrolytically.
Extractive metallurgists are interested in three primary streams: feed, concentrate (valuable metal oxide/sulfide), and tailings (waste). After mining, large pieces of the ore feed are broken through crushing and/or grinding in order to obtain particles small enough where each particle is either mostly valuable or mostly waste. Concentrating the particles of a value in a form supporting separation enables the desired metal to be removed from waste products.
Mining may not be necessary if the ore body and physical environment are conducive to leaching. Leaching dissolves minerals in an ore body and results in an enriched solution. The solution is collected and processed to extract valuable metals.
Ore bodies often contain more than one valuable metal. Tailings of a previous process may be used as a feed in another process to extract a secondary product from the original ore. Additionally, a concentrate may contain more than one valuable metal. That concentrate would then be processed to separate the valuable metals into individual constituents.

Crushing
It is the process of breaking the ore.
Concentration of Ore

Froth Flotation

Froth flotation is achieved when particles are separated based on their surface potential. Hydrophobic particles are recovered to the froth, whereas hydrophilic particles are discharged with the tailings stream. Some mineral particles are naturally hydrophobic, whereas others require specific reagent additions to change their surface potentials.Oxide ores, such as spodumene and tantalited can be treated using oxalic acid based collectors. Sulfide ores can be recovered using xanthate or dithiophosphate type collectors.

Gravity Concentration
Particles can be classified based on their specific gravity. Gravity concentration processes include:
Heavy media or dense media separation
Shaking tables, such as the wilfely table
Spirals
Centrifugal bowl concentrators
Jig concentrators

Electrostatic Separation
Non-conducting particles maintain an electrostatic charge induced electrically, and so remain pinned to a charged drum. Conducting particles do not maintain the electrostatic charge and so fall off the drum, thus minerals such as ilmenite and rutile can be separated.


Magnetic Separation
Minerals such as magnetite and pyrrhotite are naturally magnetic, and so can be separated from non-magnetic particles using strong magnets.



3 Ores of some metals

Copper can be found as native copper in mineral form. Minerals such as the sulfides: chalcopyrite (CuFeS2), bornite (Cu5FeS4), covellite (CuS), chalcocite (Cu2S) are sources of copper, as are the carbonates: azurite (Cu3(CO3)2(OH)2) and malachite (Cu2CO3(OH)2) and the oxide: cuprite (Cu2O).
Zinc is extracted from sphalerite (zinc sulfide), smithsonite (zinc carbonate), hemimorphite (zinc silicate), and franklinite (a zinc spinel).

Nickel principal ore minerals are nickeliferous limonite: (Fe, Ni)O(OH) and garnierite (a hydrous nickel silicate): (Ni, Mg)3Si2O5(OH). The second are magmatic sulfide deposits where the principal ore mineral is pentlandite: (Ni, Fe)9S8.

Iron Principal ore of iron is Haematite

Aluminium : Ores of Aluminium are

Bauxite ( Al2O3.H20)
Diaspore (Al2O3.H20)
Caryolite (Na3AlF6)
Silver Argentite

Gold Alluvial soil



4 METALS IN NEPAL

Metallic minerals found in Nepal

1.
Antimony
2.
Arsenic
3.
Bismuth
4.
Cadmium
5.
Chromium
6.
Cobalt
7.
Copper
8.
Gold
9.
Iron
10.
Lead
11.
Lithium
12.
Mercury
13.
Molybdenum
14.
Nickel
15.
Silver
16.
Tantalum-Niobium
17.
Tin
18.
Titanium
19.
Tungsten
20.
Uranium
21.
Zinc








Metals Minerals Location
1 Iron Magnetite,haemitite Phulchoki,Tanhu,Pyuthan,Bandipur,Chitwan.

2 Copper Copper and its ores
chalcopyrite,copper bornite Udaypur, Makwanpur,Chobar, Baglung.

3 Magnesium Magnesite Udaypur ,Kharidhungha

4 Gold Native Swayambhu –Halchok area Mustang

5 Zinc Sulphide,carbonate alongWith lead Phulchoki

6 Lead Galena Phulchoki

7Cobalt Cobalite
Palpa ,Gulmi


METAL INDUSTRIES OF NEPAL

Hansraj Hulas Chand & Co.
Koshi Metal Crafts Co. (P) Ltd.
Hulas Steel Industries (P) Ltd.
Hulas Metal Crafts (P) Ltd.
Apollo Steels Industries Pvt. Ltd.
Nepal Metal Co
Nepal Steel
Kamala Iron Industries
Bhagawati Carbide Industries Bhagawati Steel Industries
Hetaunda Iron & Steel Jyoti Metal Udyog
Panchakanya Steel (P) Ltd.
Panchakanya Iron Industries (P) Ltd.
Sunder Steel (P) Ltd.
Narayani Metal Udyog
Asian Metals
Shah Iron & Steel
Pashupati Iron & Steel P. Ltd.
Bageswori Iron & Steel (P) Ltd
Aqua Minerals Nepal
Vijay Metal Industries
Saakha Metal Industries (P) Ltd.
Saakha Steel Industries (P) Ltd.

6 Application

IRON: Iron is the most used of all the metals, comprising 95% of all the metal tonnage produced worldwide. Its combination of low cost and high strength make it indispensable, especially in applications like automobiles, the hulls of large ships, and structural components for buildings.

AlUMINIUM: Transportation (automobiles, aircraft, trucks, railway cars, marine vessels, bicycles etc.)
Packaging (cans, foil, etc.) ,Water treatment ,Treatment against fish parasites such as Gyrodactylus salaris. ,Construction (windows, doors, siding, building wire, etc.)
Copper: As a component of coins, often as cupronickel alloy, Copper plumbing fittings and compression tubes,Doorknobs and other fixtures in houses.

GOLD:It is used in ornaments,it is used to make goldleaf electroscope,coins etc

Silver: It is used in ornaments,it is also used in solder.

7 Feasibility of Extraction of metal from its ore in Nepal

In Nepal sizable amounts of minerals occur but these have not been fully exploited . It is believed that there are areas which have plenty of tantalum, niobium and rare metal ores .If their proper execution is carried out ,Nepal may become a major supplier of these metals .Alluvian plains of Nepal are known to have placer gold ,while the middle region has copper ,lead,zinc,iron,cobalt,nickel etc. In the snow capped areas a few deposits of lead , zinc and iron have been reported.
If we see the history of our country we can know during the period of Jung Bahadur Nepal was chief exporter of Copper in the world , huge amount of copper were exported to India from Nepal and to the Europe from India ,so we can say that we have sizable amounts of mineral in our country but we lack proper investment in this . Recently a British Company had done investment in Mahabharat region of our country and they found there could the source of petroleum . Research done some year before in Sunkoshi River had shown that , there are gold deposits in sand .From several international research several ores have been found but there are not technologies to extract metals from that ores . Now also we are extracting metals from ordinary ores that has not profit so we are not able to progress in metallurgy.

8. CONCLUSION AND SUGGESTIONS

Metal industry is one of the most important industry in the world .There are many country which have done great achievements from this industry . Our country has also great potentiality in this industry if we invest in this field .

Following things are suggested for improvement in this sector :

Government should encourage private industry for metal extraction.
Government should take technological help from other nation and manpower.
Many international companies are investigating about the ores in different parts of country with out the permission of government ,this should be controlled.
Proper strategy should be developed for this field