3. Figure 23.1 The transition elements (d block) and inner
transition elements (f block) in the periodic table.
4. Properties of the Transition Metals
All transition metals are metals, whereas main-group
elements in each period change from metal to nonmetal.
Many transition metal compounds are colored and
paramagnetic, whereas most main-group ionic compounds
are colorless and diamagnetic.
The properties of transition metal compounds are
related to the electron configuration of the metal ion.
Actinides (5f- Block elements)
Definition: The elements in which the extra electron enters 5f- orbitals of (n-2)th main shall
are known as 5f-block elements, actinides or actinones.
Thus, according to the definition of actinides only thirteen elements from Th90 (5f0 6d2 7s2 )
to No102 (5f14 6d0 7s2 ) should be the members of actinide series.
However, all the fifteen elements from Ac89 (5f0 6d1 7s2 ) to Lw103 (5f14 6d1 7s2 ) are
considered as the members of actinide series, since all these fifteen elements have same
physical and chemical properties.
In fact actinium is prototype of actinides as lanthanum is the prototype of lanthanides.
General electronic configuration of actinides is 2,8,18, 32, 5s2 , p6 d 10 f 0-14, 6s2 p 6 d 0-2 , 7s2
22. +2 oxidation state: Only Am (Americium) is known to form a stable +2 state. This state is stable in
CaF2 only and has been studied by optical and electron spin resonance spectra.+3 oxidation state: +3 state is a general oxidation
state for most of the actinides. For Th and Pa +4 and +5 state respectively are important.
+4 oxidation State:-
Principal oxidation state for Th
Very important stable state for Pu, U, Pu
Am, Cm, Bk ,& Cf are increasingly easily reduced- only stable is certain complexes, e.g Bk +4 is more oxidizing than Ce+4
MCl4 only known for Th,Pa,U,Np
+5 Oxidation state
Principal state for Pa, U,Np, Pu, and Am
e.g Fluoride PaF5, NpF5 UF5
+6 Oxidation state
Its important for Pa, Np, Pu, and Am element
Few other component e.g AnF6 (An= U ,Np, Pu) UCl6 UFO4
+7 Oxidation state
Only the marginally stable oxo-anions of Np and Pu e,g AnO3)
27. B- General Principal of Metallurgy
The increasing use of metals in day to day life increases the interest of man in their properties and thesources
from which they could be recovered. This gave birth to a new branch in chemistry called metallurgy.
1. Metallurgy: The science that deals with procedures used in extracting metals from
their ores, purifying and alloying metals and creating useful objects from metals is
2. Minerals: Natural materials found inside the earth containing metals in their
combined states (as a single compound or as a mixture of compounds) mixed with
non-metallic impurities of Earthand rock are termed minerals. i.e. Cu minerals are
oxide ores – Cu2O, CuCOz. Cu(OH)2, Sulphide minerals are Cu S. CuFeS2 etc.
3. Ores: The rocky materials which contain sufficient quantity of mineral so that the
metal can be extracted profitably or economically are known as ores. All ores are
minerals but all minerals are not ores.
i.e. a. Fe - Fe2O3.3H2O , Haematite.b. AI – Al2O.3H2O Bauxite.
4. Gangue or Matrix: The ores usually contains a large number of impurities like earth
matters ,rock stones, sand, lime stones, mica and other silicates. The seimpurities are
known as gangue or matrix.
28. Steps in metallurgy
Metallurgy involves the various steps in the extraction of pure metals from their ores
are broadly classified as follows-
1. Crushing and pulverization of the ore.
2. Dressing or concentration of the ore.
29. 1.Crushing and pulverization of the ore
These ores occur in nature as huge lumps as a big pieces. They are broken to small
pieces with the help of crushers or grinders. These pieces are then reduced to fine
powder with the help of a ball mill or stamp mill. This process is called pulverization.
Depending upon the nature of the ore, one or more of the following steps are taken to
concentrate theore. These are mostly physical method.
The terms Pyrometallurgy is related to metallurgical process, involving the use of
heat for the treatment at high temperature, includes smelting and roasting.
It involves heat in gin a blast furnace at temperatures above 1500°C to convert waste
to a form that can be refined.
The oxide waste is heated with are ducing agent, such as carbon in the form of coke
or coal; the oxygen of the metal combines with the carbon and is removed in carbon
The waste material in e-waste(non-metallic parts) is called gangue; it is removed by
means of a substance called a flux which, when heated, combines with it to form a
molten mass called slag.
Being lighter than the metal, the slag floats on it and can be skimmed or drawn off.
Pyrometallurgy the basic operation is the direct introduction of e-waste into a
furnace mixed with are ducer and smelting agent.
This operation is accompanied with strong gas emissions including:-CO2 -CO
coming from oxidation of carbon used as the reducer dust of scrap metals and other
components, greenhouse effect gases like SO2, Cl2, HCl and NOX, Organic volatile
In pyrometallurgy, almost allwaste content is burnt to ashes or carbon and leaving
behind also a mixture of heavy metals. Useful materials such as plastics, which
might otherwise be further recycled into re-engineering plastic are also being burnt
(this is in the event that feed materials did not go through initial mechanical
separation stage).Other lesser important content such as paper, ceramics, glass and
fibers which could also be reused as filler or flux in certain products are also non-
Hydrometallurgy, sometimes called leaching, involves the selective dissolution of metals from
It involves the use of aqueous chemicals and much lower temperatures to separate metal. Metal
is recovered by electrolysis of the solution.
If metal obtained from waste still contains impurities, special refining processes are required.
Hydrometallurgy generates some hazardous gases such as chlorine, noxiou sand hydrogen
cyanide gases which is possible to be treated by a simple 1-3 stage scrubber system with a
chemical scrubbing solution.
In contrast to a furnace process, chemical process also generates waste water.No gases can
escape and solvents are fully trapped at room temperature, where it is not in position toproduce
dioxins or other greenhouse effects.Hydrometallurgy is more environmentally friendly also as
sulphur is presented as a stable sulphate orelemental sulphur rather than sulphur dioxide
By using hydrometallurgy, almost all waste components (not only heavy metals) could be
segregated and recovered for further recycling or re-use Leaching processes produce residues,
while effluent treatment results in sludges which can be sent formetals recovery.
Hydrometallurgy leads to a higher recovery rate due to relative ease in leaching of product and
the possibility of cascading - re-circulating solid waste to the next step and achieving a high
recovery rate with chemical precipitation of electro-winning.mofining that involves the use of
water & aqueous