How to Start a Sponge Iron Plant in India

Most new sponge iron plants in India run on coal, not gas, and that choice sets the machinery, the approvals and the cost. In a coal-based plant, iron ore, non-coking coal and a little dolomite go into a rotary kiln, a long tilted cylinder, and the ore loses its oxygen without ever melting. What comes out is porous metallic iron, sold as sponge iron, that induction-furnace and arc-furnace steel makers buy in place of scrap.

Before you price a kiln, price your inputs. Ore and coal are bought, sponge iron sells at a rate that follows scrap, and the spread is the whole business. NPCS project reports show a 50 tonne-a-day plant at ₹18 crore total capital investment and a 135,000 tonne-a-year plant at ₹89.23 crore.

Where are sponge iron plants concentrated in India, and where should a new one go?

India has been the world's largest sponge iron producer every year since 2003, says the Ministry of Steel's Annual Report 2025-26. Output was 55.764 million tonnes in 2024-25, and coal-based kilns made 85% of the April to December 2025-26 total (provisional).

BigMint's provisional data for April to September 2025 shows the leaders and where new kilns are announced.

BigMint says total capacity could pass 70 million tonnes by FY2030, so a newcomer competes with established groups for the same ore and coal. Choose the site by delivered cost of ore and coal first and distance to buyers second.

How is sponge iron made in a coal-based rotary kiln?

A Thapar University thesis on coal-based kilns puts the temperature profile at roughly 800°C to 1,050°C and iron ore use at 1,500 to 1,600 kg per tonne of sponge iron.

1. Prepare the feed. Ore, non-coking coal and dolomite are crushed, screened and stored separately.
2. Charge the kiln. Feed enters the high end of a slightly inclined, rotating kiln; more coal is blown in from the discharge end.
3. Reduce the ore. Coal burns and gasifies, carbon monoxide strips oxygen from the ore, and solid iron remains. The kiln never reaches the melting point of iron.
4. Cool and separate. A rotary cooler keeps air away; magnetic separators then pull sponge iron out of the char and screens split lump from fines.
5. Clean the exhaust. Kiln gas passes an after-burner, a heat-recovery boiler and a dust collector before the stack.

Buyers pay for grade: the thesis gives a typical coal-based product at 91% to 93% total iron and 90% to 92% metallisation (the share of iron already metallic).

Gas-based kilns made 8.88 million tonnes in 2024-25 against 46.883 million tonnes from coal, the Ministry report shows. Choose coal unless you already hold a long-term natural gas contract at a workable price.

Which machines does a sponge iron plant need?

The kiln is the biggest purchase, but the dust collector and boiler decide whether the plant can run within its consent.

How much does a sponge iron plant cost? Two NPCS project reports compared

The two NPCS reports describe different projects, so read this as two data points, not a curve. Return and break-even figures are each report's own base case.

On 300 working days, 135,000 tonnes a year is about 450 tonnes a day: nine times the output for about five times the investment. Kiln count, waste heat power, dust control, land and stock financing drive the figure at any size. NPCS has prepared project reports since 1994, more than 5,000 across 40-plus sectors. Cost varies with capacity, location and technology, and a lender will want a project-specific report.

Which approvals does a sponge iron plant need, and in what order?

Start the pollution approvals before you order the kiln, because they set the schedule.

The Central Pollution Control Board notified sponge iron emission standards in 2008. Ask your state board which dust limit it will write into your consent before you order the dust collector.

What squeezes margins in a sponge iron plant?

The squeeze was visible in 2025. BigMint reported the Raipur benchmark falling to ₹22,900 a tonne, a level last seen in October 2020, and mid-sized producers cutting output by about 30% by late in the second quarter of 2025-26. It cited excess supply, weaker coal prices and soft rolling-mill demand.

• Input quality: Coal grade affects product quality and kiln output, so buy on tested specifications, not price alone. If you plan to secure ore yourself, read the guide to the iron ore mining business first.
• Price: Sponge iron follows scrap and steel demand, and you cannot pass a cost rise on to buyers.
• Buyers: Induction furnaces made 38.2% and arc furnaces 20.8% of India's 2024-25 crude steel, the Ministry report shows, so demand is broad, but each buyer compares you with scrap.

If you cannot name two furnace owners who will sign for the first year's output, do not order the kiln.

What to do before you order a sponge iron kiln

1. Fix the supply. Get ore and coal quotes with tested samples from two sources in your shortlisted belt.
2. Shortlist sites. Ask the state pollution board which dust limit and siting distances apply to two industrial areas.
3. Line up buyers. List induction and arc furnace units within trucking distance and seek written intent for year-one output.
4. Choose the scale. Ask kiln makers for guaranteed output on your actual materials and compare the cost per tonne of capacity.
5. Build the numbers. A detailed project report turns these steps into the cost and cash flow a lender reads, and the MSME schemes show what support you may qualify for. For other metal projects, see steel business ideas.

An NPCS project report on sponge iron covers the process with a flow sheet, plant and machinery with suppliers, raw materials, plant layout and the financials a bank asks for. It supports your own quotes and site checks and does not replace them.

Frequently asked questions about sponge iron plants

Why is it called sponge iron?

Taking the oxygen out of the ore leaves a network of small pores, so the lumps look like a sponge. The iron stays solid throughout, which is why the product is also called direct reduced iron.

Is sponge iron the same as pig iron?

No. Pig iron is made in a blast furnace, where ore is melted with coke and comes out as a liquid. Sponge iron is reduced in the solid state at a lower temperature and melted later by the steel maker, usually in an induction or electric arc furnace.

What happens to the char from the kiln?

Char is semi-burnt coal separated from the product after the cooler. A Maharashtra board consent for a plant making 6,000 tonnes of sponge iron a month listed 900 tonnes of char a month and barred dumping it on farmland, so plan where the char goes before the kiln starts.

Is a sponge iron plant profitable?

It can be while the gap between the sponge iron price and the cost of ore and coal holds. The NPCS reports list returns of 41% and 42% on base assumptions, yet in 2025 BigMint recorded mid-sized producers cutting output by about 30%. Test your model against a low-price year first.