Ferro Silicon:

Ferro Silicon is an alloy called  silicon (Si O2 ) with small percentage of Aluminum ( Al2 O3) and many other elements. The Ferro alloys are used  for manufacturing different variety steels for different uses. The different variety alloying elements used in steel manufacturing are Manganese, Silicon, Chromium, Nickel, Molybdenum, Vanadium, Tungsten, Titanium etc.No steel can be manufactured without the use of  Ferro alloys.  Ferro silicon is used as alloying element in manufacturing  of spring steel, transformer steel and  other types of alloys steels.    Ferro silicon is a chemical which helps in maintaining carbon contents in the steel  at the desired level and makes it usable for different purposes. The requirement and importance of Ferro alloys are directly  connected with the requirements and importance of  steel.  Since the steel is playing a significant role  in the development of modern society  and the industrial development of our country, the ferro alloys  are equally  important for the same. India is one of the largest steel manufacturing  country in the world and  the Ferro Alloys   are  important element for manufacturing iron & steel. The annual consumption of Ferro Silicon  in our country  is around 145 thousand tones where as annual  domestic production is 74.5 thousand tonnes.

Chemical composition :

Manufacturing process :

The Ferro Silicon is manufactured in  electric operated submerged arc furnace The manufacturing process of Ferro Silicon can be broadly classified into four steps. 

a)  Blending of raw materials

b)  Charging and smelting in the arc furnace

c)  Tapping  and cooling  of molten materials

d)  Breaking, Cleaning and packing .

a)  Blending of Raw Materials:

 Quartz,  Charcoal and M.S. scrap are  mixed in the required quantity and lifted to the charging platform with the help of the lifting arrangements. The raw materials are generally mixed in the following proportion in terms of weight.

   Quartz  -        53 %

   Charcoal -      35%

   M.S. Scrap  - 12%

 b) Charging of raw materials:

The blended raw materials are charged to the furnace  with the help of  hoist and charging chutes at a regular interval. In the furnace  three carbon electrodes are partially submerged in the charge , which are supported  by hydraulic cylinders for upward and down ward movements . The electrodes helps in maintaining desired electric conditions in the furnace.  The chemical reaction starts at a temperature of  1600 C. to 1700 C.  In the reaction zone of the furnace the  silica reacts with the reductants and after reaction, a mixture of iron and silicon trickles down and gets collected at the bottom of the furnace crucible. The impurities present in the form of molten slag are collected in vessel.

c) Tapping and cooling .

Three tap holes are provided  at the bottom of the furnace  for tapping both molten alloys and slag. During repair work of the Tap hole functions and the other works as standby .

As the charge enters the smelting zone, the alloy formed by chemical reactions of the oxides and the reductant, being heavy, gradually settles at the bottom.  At a regular intervals of 2 to 2.5 hours the furnace is tapped. The tap hole is opened by Oxygen lancing pipe and after tapping is completed, it is closed by clay plugs. The liquid Ferro silicon is collected in the tapping pot and cast  on the dressed sand beds for solidification and cooling. 

d) Breaking cleaning and packing .

After solidification the cakes are broken manually with help of hammers  to reduce to the required lump sizes after being removal of undesired particles if any, like slag contents etc.,   After cleaning and breaking  laboratory test in conducted for checking quality and composition. Finished goods are then packed in  either jute bags/ P.P. bags ready for dispatch.