Ferrosilicon

Ferro alloys are one of the important inputs in the manufacture of alloys and special steel. Ferro-alloys impart special properties to steel in terms of increasing resistance to corrosion, oxidation to improve hardness, tensile strength at high temperatures, wear and abrasion resistance with addition of carbon to increase creep strength, etc. The growth of ferro-alloys industry is, thus, linked with the development of the iron and steel industry, foundry industry and to some extent, electrode industry. The principal ferro-alloys are of chromium, manganese and silicon. The product series consists mainly of ferro- manganese, silico-manganese, ferro-silicon and ferro-chrome.

Ferro-alloys are classified into two main categories: i) bulk ferro-alloys and ii) noble ferroalloys

• Bulk Ferro Alloys: HC Ferro Manganese, Silico Manganese, Ferro Silicon, HC Ferro Chrome, Charge Chrome etc.
• Noble Ferro Alloys : Ferro Molybdenum, Ferro Vanadium, Ferro Tungsten, Ferro Silico Zirconium, Ferro Titanium, Ferro Boron etc.

Ferrosilicon

Ferrosilicon, or ferrosilicium, is an alloy of iron and silicon comprising 15% to 90% silicon along with high proportion of iron silicides and 1 to 2% of calcium and aluminium. Its melting point is about 1200 °C to 1250 °C with a boiling point of 2355 °C. Ferrosilicon finds application across several end use sectors as highlighted in the table below.

Ferrosilicon is produced by reduction of quartzite with coke in presence of scrap iron/ mill scale, or other source of iron. Ferrosilicon with silicon content up to about 15% is made in blast furnaces lined with acid fire bricks while Ferrosilicon with higher silicon content is made in electric arc furnaces. Micro silica or the silica fumes is obtained as a useful by product during the production of ferrosilicon.

Further, it may be noted that ferrosilicon production is a power intensive process. Based on inputs from industry players, around 8000 – 9000 units of electricity is required per MT of ferrosilicon production, thereby accounting for around 35 – 40% of the total cost of ferrosilicon production.

 Domestic Production

On account of significant availability of one of the key raw materials i.e. Quartzite along with low cost power, Ferrosilicon manufacturing has emerged as one of the key industrial activities in Bhutan. In terms of installed production capacity, the ferrosilicon industry in Bhutan is estimated at around 0.1 mn MT. During 2011, the total production of ferrosilicon in Bhutan is estimated at around 0.095 – 0.1 mn MT translating into capacity utilization of around 95 -100%. The detail of the industry players in terms of their installed capacity and location is presented in the table below.

Based on discussion with the industry players in Bhutan, it is observed that all the production facilities employ submerged arc technology on account of effective power utilization, higher productivity, etc. With the exception of Bhutan Ferro Alloys Ltd, which has an aggregate capacity of 46 MVA (28 MVA and 18 MVA) all other manufacturers have furnace with a capacity of 18 MVA. Further, it may be noted that with the exception of Bhutan Ferro Alloys (a joint venture with RGoB), all the other ferrosilicon production facilities are owned by the private players.

It is observed that Ferrosilicon industry in Bhutan is primarily dependent on exports with nearly 90% (i.e. 88,812 MT; Source: Bhutan Trade Statistics, 2010) of the total production of ferrosilicon being exported to India during 2010. In terms of value, the total export of ferrosilicon to India has registered a CAGR of 77% during the period 2006-10 (2006: Nu.559.1 Mn; 2010: Nu. 5471.3 Mn).

Eastern Bhutan

Currently, SD Eastern Bhutan Ferro Silicon Pvt. Ltd. (which commenced production in 2007) is the only manufacturer of ferrosilicon in the eastern region of Bhutan. Equipped with 2 furnaces of 9 MVA each, it has a total installed production capacity of 15,000 MT per annum and employs submerged arc technology for production of ferrosilicon. In 2010, the company exported its entire production of around 14,800 MT of ferrosilicon to India. It has a production facility located in Matanga Industrial Estate in Samdrup Jongkhar. For purpose of manufacturing ferrosilicon, it imports its entire requirement of raw material (including quartzite / quartz) from India. While Quartz is sourced primarily from Meghalaya and Assam, other key raw materials like Charcoal is sourced from Andhra Pradesh, Coal from Meghalaya and mill scale from secondary steel manufacturers located in Jharkhand. It sources its entire electricity requirement from Kurichhu Hydro project.

Based on discussion with Department of Geology and Mines, it is observed that there are proven reserves of quartzite at Mukka Zor near Trashigang on the Samdrup Jongkhar – Trashigang highway. However, the same has not been exploited as yet.