In the extraction of metal different types of furnaces are used. Each furnace has its own characteristics. Some principal furnaces have been described below,
(1) Blast furnace : It is a special type of tall cylindrical furnace, about 100 feet high with a diameter of 15-28 feet. It is made of steel sheets lined inside with fire-proof bricks. The charge is added through a cup and cone arrangement at the top. At the upper part of the furnace there is a hole for the escape of the waste gases of the furnace. There are two outlets in the hearth of the furnace, one for tapping the molten metal and the other above it for the slag. The waste gases are heated and a hot air blast under pressure is blown into the furnace by means of bellows or fans through water cooled nozzles ortuyers. The temperature of the furnace varies from 250oC. to 1500oC. Thus the charge descends slowly into zone of increasing temperatures. The blast furnace is used for the extraction of metal like copper and iron.
(2) Reverberatory Furnace : In this furnace fuel burns in a separate part and does not mix with the charge. The furnace may be divided into 3 parts,
(i) Fire Grate : It is on one side where the fuel burns.
(ii) Flue or Chimney : It is on the other side of the fire grate. The waste gases escape through it.
(iii) Hearth : It is the middle part of the furnace where the charge is heated with the flames and hot gases.
The material to be heated is placed on the hearth or bed of the furnace and is heated by the hot gases or flames produced by the burning of fuel. The waste gases escape out of the chimney. Since the fuel does not come in contact with the charge, the furnace is very suitable for calcination and roasting and is employed for both oxidising and reducing purposes. For oxidation, the material is heated by the current of hot air while for reduction the material is mixed with coke and heated. The furnace find wide application in the extractive metallurgy.
(3) Electric Furnace : The fuel burnt furnaces described in this chapter produce temperature in the range of 1000-1500oC. Although these furnaces have the great utility in the extraction of metals yet these are unsuitable where higher temperatures are needed. One commonly used electric furnace is Heroult's furnace shown in fig. It consists of a steel shell lined inside with dolomite or magnesite. It is provided with movable water jacketed electrodes suspended from the roof or from the sides. Heat is generated by striking an arc between the electrodes, thereby, a temperature of over 3000oC may be reached. The charge melts and the impurities e.g., Si, Mn, P and S etc. present in the ore combine with the more...
The group 1 of the periodic table contains six elements, namely lithium (Li), sodium (Na), potassium (K), rubidium (Rb), caesium (Cs) and francium (Fr). All these elements are typical metals. Francium is radioactive with longest lived isotope with half life period of only 21 minute. These are usually referred to as alkali metals since their hydroxides form strong bases or alkalies.
(1) Electronic configuration
The group 2 of the periodic table consists of six metallic elements. These are beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba) and radium (Ra). These (except Be) are known as alkaline earth metals as their oxides are alkaline and occur in earth crust.
(1) Electronic configuration
Element
Electronic configurations (\[n{{s}^{2}}\])
\[_{4}Be\]
\[[He]\,2{{s}^{2}}\]
\[_{12}Mg\]
\[[Ne]\,3{{s}^{2}}\]
\[_{20}Ca\]
\[[Ar]\,4{{s}^{2}}\]
\[_{38}Sr\]
\[[Kr]\,5{{s}^{2}}\]
\[_{56}Ba\]
\[[Xe]\,6{{s}^{2}}\]
\[_{88}Ra\]
\[[Rn]\,7{{s}^{2}}\]
Radium was discovered in the ore pitch blende by madam Curie. It is radioactive in nature.
(2) Occurrence : These are found mainly in combined state such as oxides, carbonates and sulphates Mg and Ca are found in abundance in nature. Be is not very abundant, Sr and Ba are less abundant. Ra is rare element. Some important ores of alkaline earth metals are given below,
(i) Baryllium : Beryl (3BeO.Al2O3.6SiO2); Phenacite (Be2SiO4)
(ii) Magnesium : Magnesite (MgCO3); Dolomite (CaCO3. MgCO3); Epsomite(MgSO4. 7H2O); Carnallite (MgCl2.KCl. 6H2O); Asbestos [CaMg3(SiO3)4]
(iii) Calcium : Limestone (CaCO3); Gypsum : (CaSO4.2H2O), Anhydrite (CaSO4); Fluorapatite [(3Ca3(PO4)2.CaF2)] Phosphorite rock [Ca3(PO4)2]
(iv) Barium : Barytes (BaSO4) ; witherite (BaCO3)
(v) Radium : Pitch blende (U3O8); (Ra more...
Group 13 of long form of periodic table (previously reported as group III A according to Mendeleefs periodic table) includes boron (B) ; aluminium (Al) , gallium (Ga), indium (In) and thallium (Tl) Boron is the first member of group 13 of the periodic table and is the only non-metal of this group. The all other members are metals. The non-metallic nature of boron is due its small size and high ionisation energy. The members of this family are collectively known as boron family and sometimes as aluminium family.
(1) Electronic configuration
(2) Occurrence : The important of this group elements are given below,
Boron : Borax (Tincal) (Na2B4O7.10H2O), Colemanite (Ca2B6O115H2O)
Boracite (2Mg3B8O15.MgCl2), Boronatro calcite (CaB4O7.NaBO2.8H2 O),
Kernite (Na2B4O7.4H2O), Boric acid (H3BO3)
Aluminium : Corundum (Al2O3), Diaspore (Al2O3.H2O), Bauxite (Al2O3. 2H2O), and Cryolite (Na3AlF6).
Physical properties
(1) A regular increasing trend in density down the group is due to increase in size.
(2) Melting points do not vary regularly and decrease from B to Ga and then increase.
(3) Boron has very high melting point because it exist as giant covalent polymer in both solid and liquid state.
(4) Low melting point of Ga (29.80C) is due to the fact that consists of only Ga2 molecule; it exist as liquid upto 20000C and hence used in high temperature thermometry.
(5) more...
Carbon is the first member of group 14 or IVA of the periodic table. It consists of five elements carbon (C), silicon (Si), germanium (Ge), tin (Sn) and lead (Pb). Carbon and silicon are nonmetals, germanium is metalloid and tin and lead are metals.
(1) Electronic configuration
Physical Properties
(1) Non-metallic nature : The non-metallic nature decreases along the group.
C Si Ge Sn Pb
Non-metals metalloid metal metal \[\]
(2) Abundance : Carbon and silicon are most abundant elements in earth’s crust whereas germanium occurs only as traces. Tin and lead also occur in small amounts. Only carbon occurs in free state as coal, diamond and graphite and in combined state as carbonates, CO2 petroleum and natural gas Silicon is the second most abundant element after oxygen in earth’s crust in form of silicates and silica. Germanium found in traces in coal and in certain deposits. It important constituent for making conductors and transistors The important ore of tin is tin stone (SnO2) or cassiterite. Lead is found is form of galena (PbS) anglesite (PbSO4) and cerussite (PbCO3) The abundance ratio in earth’s crust is given below,
(3) Density : The density of these elements increases down the group as reported below
Element C Si Ge Sn Pb
Density more...
Nitrogen is the first member of group 15 or VA of the periodic table. It consists of five elements nitrogen (N), phosphorus (P), arsenic (As), antimony (Sb) and bismuth (Bi). The elements of this group are collectively called pnicogens and their compounds as pniconides. The name is derived from Greek word ?Pniomigs? meaning suffocation. Pniconide contain \[{{M}^{3-}}\] species.
(1) Electronic configuration
Physical properties
(1) Physical state : Nitrogen– (gas), phosphorus – (solid) (vaporises easily), As, Sb, Bi–solids.
Nitrogen is the most abundant gas in the atmosphere. It constitutes about 78% by volume of the atmosphere. Phosphorus is the most reactive element in this group and its yellow form is always kept under water.
(2) Atomic radii : Atomic radii increases with atomic number down the group i.e., from N to Bi due to addition of extra principal shell in each succeding elements.
(3) Ionisation energy : The ionisation values of the elements of this group decreases down the group due to gradual increases in atomic size.
(4) Electronegativity : Generally the elements of nitrogen family have high value of electronegativity. This value shows a decreasing trend in moving down the group from nitrogen to bismuth.
(5) Non-metallic and metallic character : Nitrogen and more...
Fluorine is the first member of group 17 or VIIA of the periodic table. It consists of five elements Fluorine (F), Chlorine (Cl), bromine (Br), iodine (I) and astatine (At). These are known as halogen because their salts are found in sea water. Halogen is a greek word meaning a sea salt.
(1) Electronic configuration
Physical properties
(1) Atomic and ionic radii : A halogen atom has the smallest radius as compared to any other element in its period. This is due to the increased effective nuclear charge which results in greater attraction of the electrons by the nucleus. The atomic radii. Increase from fluorine to iodine down the group due to increase in number of shells.
Helium is the first member of group 18 or zero of the periodic table. It consists of six elements helium (He), Neon (Ne), argon (Ar), krypton (Kr), xenon (Xe) and radon (Rn). Zero group occupies the intermediate position between the elements of VIIA (17th) and IA (1st) groups. These are collectively called as inactive gases or inert gases. However, these are now called noble gases as some compounds of these gases have been obtained under certain specific conditions. (1) Electronic configuration
Certain elements of 2nd period show similarity with their diagonal elements in the 3rd period as shown below :
Thus, Li resembles Mg, Be resembles Al and B resembles Si. This is called diagonal relationship and is due to the reason that these pairs of element have almost identical ionic radii and polarizing power (i.e. charge/size ratio). Element of second period are known as bridge elements.
Anomalous behaviour of the first elements of a group: The first element of a group differs considerably from its congeners (i.e. the rest of the element of its group). This is due to (i) small size (ii) high electronegativity and (iii) non availability of d-orbitals for bonding. Anomalous behaviour is observed among the second row elements (i.e. Li to F).
(1) Atomic volume : It is defined as the volume occupied by one gram atom of an element. Mathematically,
\[\text{Atomic}\,\text{volume}\,=\,\frac{\text{Gram}\,\text{atomic}\,\text{weight}}{\text{Density}\,\text{in}\,\text{solid}\,\text{state}}\]
Units of atomic volume are c.c./mole. Atomic volume signifies the volume occupied by one mole (Avogadro number) of atoms of the given element in solid state. Lower atomic volume generally leads to higher density, increased hardness and brittleness, higher melting and boiling points, less malleability and ductility.
(i) While descending a group, the atomic volume generally increases which is due to increase in the number of shells though the valence electrons in a given group remains constant. (ii) While going left to right across a period the atomic volume first decreases to a minimum and then increases. Francium has the highest atomic volume and boron has lowest atomic volume.
(2) Density : The density of the elements in solid state varies periodically with their atomic numbers. At first, the density increases gradually in a period and becomes maximum somewhere for the central members and then starts decreasing afterwards gradually.
(3) Melting and boiling points : The melting points of the elements exhibit some periodicity with rise of atomic number. It is observed that elements with low values of atomic volumes have high melting points while elements with high values of atomic volumes have low melting points. In general, melting points of elements in any periodic at first increase and become maximum somewhere in the centre and thereafter begins to decreases.
Tungsten has the maximum melting point (3410°C) amongst metals and carbon has the maximum melting point (3727°C) amongst non-metals. Helium has the minimum melting point (-270°C). The metals, \[Cs,Ga\] and Hg are known in liquid state at 30°C.
The boiling points of the elements also show similar trends, however, the regularities are not so striking as noted in the case of melting points.
(4) Oxidation state (Oxidation number, O.N.) : Oxidation number of an element in a compound is the total number of electrons it appears to have gained or lost (negative and positive oxidation states respectively) during the formation of that particular compound.
Note : For detail see chapter redox reaction.
(5) Magnetic properties : Magnetic properties of matter depend on the properties of the individual atoms. A substance (atom, ion or compound) capable of being attracted into a magnetic field is known as paramagnetic. The paramagnetic substances have a net magnetic moment which in turn is due to the presence of unpaired electron(s) in atoms, ions or molecules. Since most of the transition metal ions have unpaired d-electrons, they show paramagnetic behaviour. The exceptions are \[S{{c}^{3+}},\,T{{i}^{4+}},\,Z{{n}^{2+}},\,C{{u}^{+}},\] etc. which do not contain any unpaired electron and hence are diamagnetic.
On the other hand, a substance which is repelled by a magnetic field is known as diamagnetic. Such substances do not have any net magnetic moment because they do not have any unpaired electron. Electrons determine the magnetic properties of matter in two ways,
Each electron can be treated as a small sphere of negative charge spinning more...
(2) Reverberatory Furnace : In this furnace fuel burns in a separate part and does not mix with the charge. The furnace may be divided into 3 parts,
(i) Fire Grate : It is on one side where the fuel burns.
(ii) Flue or Chimney : It is on the other side of the fire grate. The waste gases escape through it.
(iii) Hearth : It is the middle part of the furnace where the charge is heated with the flames and hot gases.
The material to be heated is placed on the hearth or bed of the furnace and is heated by the hot gases or flames produced by the burning of fuel. The waste gases escape out of the chimney. Since the fuel does not come in contact with the charge, the furnace is very suitable for calcination and roasting and is employed for both oxidising and reducing purposes. For oxidation, the material is heated by the current of hot air while for reduction the material is mixed with coke and heated. The furnace find wide application in the extractive metallurgy.
(3) Electric Furnace : The fuel burnt furnaces described in this chapter produce temperature in the range of 1000-1500oC. Although these furnaces have the great utility in the extraction of metals yet these are unsuitable where higher temperatures are needed. One commonly used electric furnace is Heroult's furnace shown in fig. It consists of a steel shell lined inside with dolomite or magnesite. It is provided with movable water jacketed electrodes suspended from the roof or from the sides. Heat is generated by striking an arc between the electrodes, thereby, a temperature of over 3000oC may be reached. The charge melts and the impurities e.g., Si, Mn, P and S etc. present in the ore combine with the more... 
with half life period of only 21 minute. These are usually referred to as alkali metals since their hydroxides form strong bases or alkalies.
(1) Electronic configuration
Thus, Li resembles Mg, Be resembles Al and B resembles Si. This is called diagonal relationship and is due to the reason that these pairs of element have almost identical ionic radii and polarizing power (i.e. charge/size ratio). Element of second period are known as bridge elements.
Anomalous behaviour of the first elements of a group: The first element of a group differs considerably from its congeners (i.e. the rest of the element of its group). This is due to (i) small size (ii) high electronegativity and (iii) non availability of d-orbitals for bonding. Anomalous behaviour is observed among the second row elements (i.e. Li to F). 
