01-02-2013, 11:23 AM
INDIAN FERRO ALLOY INDUSTRY - PRESENT STATUS AND FUTURE OUTLOOK
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ABSTRACT
Steel is the most versatile material, which has made the progress in every aspect on this
earth possible. There are hundreds of varieties of steel because for each application it has to
be made with specific properties to get the most optimum usage. Though the basic
constituent of steel is iron, it is the proportion of other elements in it, which gives each type
of steel certain specific properties. These elements are added in liquid iron in the form of
Ferro alloys to get the desired composition and properties. Thus, Ferro alloys are important
additives in the production of steel and Ferro Alloys industry is vitally linked for its growth and
development to that of the Steel Industry.
There are two major groups of alloys.
1. Bulk alloys consisting of ferro alloys of Manganese, Chromium, Nickel and Silicon which
are added in larger proportion to steels and are made by carbo thermal reduction in
submerged arc electric furnaces(SAF). A schematic diagram of a submerged electric arc
furnace is given in Annexure 1.
2. Noble ferro alloys which are used in much smaller proportion in special and alloy steels
for addition of vanadium, molybdenum, Tungsten, Zirconium, Titanium, Boron,
Tantalium, Magnesium Silicon and extra Low Carbon Ferro Chrome etc. These are
generally made by alumino thermic or silico thermic reduction processes.
INDUSTRY’S PROFILE
Ferro alloys production in India is about six decades old. In India bulk ferro alloys production
through electric submerged arc furnace route made a beginning in late 1950s. After the
invention by Soderberg of self- baking type electrodes, during 1920s, this became the most
preferred way for making bulk ferro alloys of Silicon, Manganese & Chromium in the world.
FIRST PHASE OF THE INDUSTRY IN INDIA
The initial/first phase of the industry is marked by the installation of small capacity furnaces
mostly for the production of Manganese alloys with the starting up of the first furnace at
VISL, Bhadravati, total of 18 furnaces were commissioned by the mid-sixties to cater to the
domestic steel industry’s requirement. The status of the Indian Ferro Alloy industry by midsixties
is given in the table-1.
Second phase expansion
With the advent of production of stainless steel and alloy steels in India, of which
Chromium is the most important ingredient, the chromium alloys production with totally
indigenous raw materials, in view of restrictions on imports then, was innovated through
research and developmental studies during sixties. Ferro Alloys Corporation Ltd., after
successfully proving its production with Indian chrome ores, Giridhi low phos coke and noncoking
coal in the 500 KVA pilot SAF at National Metallurgical Laboratory, Jamshedpur,
started industrial scale production of chrome alloys in 1967.[1]&[4].
First, FACOR commissioned their 12 MVA, SAF for production of High carbon ferro chrome
and Silico Chrome, then after installation of rotary kilns for pre-heating of ore fines and for
calcination of lime-stone, they were fed to an 8 MVA tilting type open arc furnace for the
production of Low carbon ferro chrome. started.
Thus the second phase of expansion of the industry took place between late sixties and late
seventies, when 13 (thirteen) more moderately sized furnaces were added to undertake
production of Silicon and Chromium alloys. The brief details of capacity additions are given in
table-2.
Third phase of expansion:
The third phase of expansion in the country was prompted by product diversification,
availability of advanced technology and encouragement from Government by way of
incentives for setting up 100% export oriented plants, to earn valuable foreign exchange.
Ferro Alloys Corporation Ltd., again for the first time in the country have pursued a strategy
to utilize the disseminated ores, run of mine ore rejects and waste dumps containing on an
average about 20% Cr203 in their Boula Mining lease. They sponsored beneficiation
studies on these in Regional Research Laboratory, Bhubaneswar, and with the process flowsheet
developed on these studies, they set up a pilot plant for chrome ore beneficiation at
their plant in Andhra Pradesh and achieved excellent results by up-gradation of such ore
rejects and fines to concentrates containing more than 40% Cr203 with Cr/Fe ratio about 2
and SiO2 4 - 6%. The development work was also carried out to mix these concentrates
along with naturally occurring ore fines to form into briquettes which have the required
crushing strength for being fed to the smelting furnaces.[2][4]. The feasibility for production
of charge chrome (Cr 55-60%) using low grade lumpy chrome ores along with these
briquettes was established and proved to an Expert Committee appointed by the Ministry of
Steel in April 1979, in one of their sub-merged arc furnaces at Shreeramnagar. About 500
tonnes of charge chrome was produced and exported to consumers abroad.
REVIEW OF TECHNOLOGY ADOPTED
Some of the recent plants have incorporated latest technologies to use both lumps as well as
fines after necessary beneficiation and agglomeration. Also they have installed effective
pollution control measures in the form of bag filters for gas cleaning after waste heat
recovery.
Although the basic technique of ferro alloy production in submerged arc electric furnace has
not undergone any major change, the design, the size, automation and control features of
ferro alloy furnaces have undergone substantial changes in the recent past in order to meet
the changing raw materials conditions and to achieve higher productivity, and better economy
of operation and conservation of energy.
There are some well-known processes, which have been developed and adopted on large
scale elsewhere in the world. For instance