What is a caustic soda project report?
A caustic soda project report is a detailed project report (DPR) for a plant that splits purified salt brine in membrane cells into caustic soda lye, chlorine and hydrogen. It sets out the process, power and salt use, machinery, approvals, project cost, means of finance, five-year projections, DSCR and break-even that lenders and investors need.
Chemical companies, alumina and viscose producers and investors use it to size the plant; banks use it to test whether the project can repay.
Also known as: project report on caustic soda, caustic soda business plan, chlor-alkali plant project report, sodium hydroxide plant feasibility report.
Caustic soda manufacturing plant cost in India
Our sample report models a 160 MT per day membrane cell plant that sells 48–50% lye. It runs 330 days a year, starting at 60% capacity and reaching 80% in Year 5.
Caustic soda is priced at ₹45,100 per MT on a 100% NaOH basis. Chlorine and hydrogen are taken at nil value, which is how many lenders prefer to see a first plan. Indicative cost for plants of 100–200 MT per day is ₹150–350 crore.
| Land and site development | 655.42 |
|---|---|
| Building and civil works | 2,729.76 |
| Plant and machinery | 14,034.77 |
| Other fixed assets | 1,243.48 |
| Contingencies | 838.23 |
| Preliminary and pre-operative | 487.54 |
| Working capital margin | 333.94 |
| Total | 20,323.14 |
| Promoter's contribution (25%) | 5,080.78 |
|---|---|
| Term loan from bank (75%) | 15,242.36 |
| Cash credit limit (separate) | 1,001.83 |
| Total project cost | 20,323.14 |
Term loan at 10.5% with an 18-month moratorium and 84 monthly instalments. Sample figures are illustrative; the ₹150–350 crore range is indicative.
Caustic soda manufacturing process in a membrane cell plant
Every new caustic soda plant is built around the chlor-alkali reaction: salt and water, with direct current, give caustic soda, chlorine and hydrogen. Each tonne of caustic comes with about 0.89 tonne of chlorine, so the plant is really two businesses.
- Brine preparation
Industrial salt is dissolved in weak brine returned from the cells to make saturated brine of about 300 grams per litre.
- Primary purification
Soda ash and caustic are dosed to settle calcium and magnesium, then the brine is clarified and filtered.
- Ion exchange polishing
Chelating resin columns bring hardness down to parts per billion, because traces of calcium foul the membranes and raise power use.
- Membrane electrolysis
Direct current from the rectifiers splits the brine: chlorine forms at the anode, and about 32% caustic and hydrogen at the cathode.
- Caustic concentration
A multiple effect evaporator raises the cell liquor to 48–50% lye for sale by tanker; some plants go on to make flakes.
- Chlorine and hydrogen handling
Chlorine is cooled, dried with sulphuric acid and compressed or liquefied; hydrogen is burnt with part of the chlorine to make hydrochloric acid.
- Storage and dispatch
Lye is tested for strength, chloride and iron before it leaves in rubber-lined or stainless steel tankers.
Which caustic soda route fits your budget?
Promoters often ask whether caustic soda can be made in a small unit. The answer depends on the route, and only one of them is used for new capacity.
| Membrane cell electrolysis | The route for new plants. Makes caustic lye, chlorine and hydrogen together. Indicative minimum scale is about 100 MT per day, because rectifiers, brine treatment and chlorine handling cost almost as much for a small plant as for a large one. |
|---|---|
| Lye to flakes unit | Buys 48–50% lye and evaporates it to 98–99% flakes over a molten salt heated concentrator and a flaker drum. Capital is much lower, but the margin is only the gap between lye and flake prices, less fuel and bags. |
| Lime-soda causticising | Reacts soda ash with slaked lime. It needs about 1.33 tonnes of soda ash per tonne of caustic, so it is viable only where soda ash is cheap or a by-product. |
| Which one our sample uses | Membrane cell electrolysis at 160 MT per day, selling lye. Flaking is left out to keep the sample simple. |
Raw materials for caustic soda
A membrane plant uses roughly 1.5–1.7 tonnes of salt per tonne of caustic, indicative. Salt quality matters more than its price: sulphate, iodine and hardness all add load on brine treatment and shorten membrane life.
Most Indian plants buy solar salt from Gujarat and Tamil Nadu and refine it on site; vacuum salt costs more but needs less treatment. Raw materials are only 13.1% of sales in our sample, because power is the big cost.
| Raw material | Share of cost | Year 3 (₹ lakh) |
|---|---|---|
| Industrial salt (solar or vacuum) | 72% | 1,566.70 |
| Soda ash and brine treatment chemicals | 16% | 348.15 |
| Hydrochloric acid and sodium sulphite | 7% | 152.32 |
| Demineralised water | 5% | 108.80 |
| Total | 100% | 2,175.97 |
Machinery for a caustic soda plant
The electrolysers are the largest single item in our sample, followed by the rectifier transformers that turn grid power into direct current. Membranes and anode coatings are replaced every few years, so the report should carry a renewal provision.
| Equipment | What it does | Sample cost (₹ lakh) |
|---|---|---|
| Salt handling and brine saturator | Stores salt and dissolves it into brine | 1,122.78 |
| Primary brine clarifier and filters | Removes settled calcium and magnesium | 1,263.13 |
| Ion exchange brine purification | Polishes brine to membrane grade | 982.44 |
| Membrane cell electrolysers | Split brine into caustic, chlorine and hydrogen | 4,491.13 |
| Rectifier transformers and DC busbars | Supply direct current to the cells | 2,245.56 |
| Caustic evaporator and storage tanks | Concentrate cell liquor to 48–50% lye | 1,122.78 |
| Chlorine drying, compression and liquefaction | Make chlorine safe to store and sell | 1,684.17 |
| Hydrogen handling and HCl synthesis unit | Use hydrogen and chlorine to make hydrochloric acid | 1,122.78 |
| Total plant and machinery | 14,034.77 | |
Costs are the sample report's estimates for a 160 MT per day plant. Get current quotations from cell technology suppliers before you finalise.
Power and utilities: the cost that decides the plant
Power, not salt, sets the cost of caustic soda. Plants are costed per electrochemical unit (ECU), meaning one tonne of caustic with its chlorine and hydrogen.
| Power use | Roughly 2,300–2,600 kWh per tonne of caustic, indicative, for cells, rectifiers, evaporation and auxiliaries |
|---|---|
| Power cost in our sample | ₹5,306.90 lakh in Year 3, 31.8% of sales |
| Power supply | A dedicated high-voltage feeder and substation; captive or open-access power is usually studied to lower the tariff |
| Steam | Needed for the caustic evaporator; some plants burn surplus hydrogen in the boiler |
| Water | Demineralised water for the cells and make-up water for the cooling towers |
| Manpower in our sample | 150 people, from management and supervision to plant operators |
Licences and approvals for a caustic soda plant
A chlor-alkali plant handles chlorine and hydrogen, so it sits in the strictest approval track. Build these timelines into the implementation schedule, as of October 2026.
| Environmental clearance | Prior environmental clearance as a chlor-alkali project under item 4(d) of the EIA Notification 2006, starting with terms of reference and an EIA study |
|---|---|
| Pollution category | Chlor-alkali is a Red category industry under CPCB criteria; consent to establish and to operate come from the State Pollution Control Board |
| Product standard | IS 252 under the Caustic Soda Quality Control Order (S.O. 1468(E), 3 April 2018); a BIS licence is needed to make or sell caustic soda |
| Factory licence | Under the Factories Act and state rules for hazardous processes |
| Power | High-tension connection sanctioned for the connected load, or approval for captive or open-access supply |
| Tax registration | GST registration before the first sale |
Market for caustic soda in India
According to the Ministry of Chemicals and Fertilizers, India had 43.04 lakh MT of caustic soda capacity in 2023-24. It produced 36.18 lakh MT, about 84% of capacity. Capacity has grown faster than demand, so a new plant needs a clear buyer base.
Most caustic moves as lye by road tanker, and freight adds up quickly, so plants sell mainly within their region. Buyers sign rate contracts and test every load for strength and iron.
- Alumina refineries
- Textile processors and viscose fibre plants
- Pulp and paper mills
- Soap and detergent makers
- Chemical, dye and pharmaceutical plants
- Water treatment chemical suppliers
Plan for chlorine first: the plant cannot run if its chlorine has nowhere to go. Projects near a PVC, chlorinated solvent or water treatment chemicals user, or with their own downstream unit, carry far less risk.
Mistakes that weaken a caustic soda project report
- Counting chlorine at a high price
Chlorine prices swing and can turn negative when there is a surplus. A report that relies on chlorine income to repay the loan will not satisfy a credit committee.
- Using an average power tariff
Power is about a third of sales. The report should use the actual tariff for your feeder or captive plant and show what a one-rupee rise does to DSCR.
- No provision for membrane renewal
Membranes and anode coatings wear out on a cycle of several years. Leaving out their replacement overstates cash flow in the later years.
- Underestimating the approvals timeline
Environmental clearance, Red category consent and the BIS licence come before production. A schedule that ignores them pushes up interest during construction.
- Pricing lye at the flake rate
Flakes sell at a premium over lye but need extra fuel, a flaker and bagging. Mixing the two prices inflates revenue.
How NPCS helps you plan a caustic soda plant
- Capacity and product mixChoose the plant size and the split between lye, flakes, chlorine and hydrochloric acid for your market.
- Power and salt economicsModel cost per ECU on your tariff, captive power options and delivered salt price.
- Bank-ready project reportProjections, DSCR, sensitivity to power and chlorine price, in the format your lender wants.
- Approvals and layoutPlant layout, chlorine safety zones and the clearance list for your state.
NPCS's client list shows 4 assignments for caustic soda and 269 in specialty chemicals, for companies and investors in India and abroad since 1994.
What's inside the caustic soda sample report
- Introduction
- Uses and applications
- Market potential
- Manufacturing process
- Raw materials
- Plant and machinery
- Land, building and utilities
- Manpower
- Licences and approvals
- Project cost and means of finance
- Working capital
- Projected profitability
- Cash flow statement
- Projected balance sheet
- Depreciation
- Term loan repayment
- Debt service coverage
- Break-even analysis
- Financial ratios
- Key assumptions
- Conclusion
- Monthly loan repayment schedule
20 pages, five-year projections, illustrative figures.
Open sample reportFree sample or a report for your project?
| What you get | Free sample | NPCS report for your project |
|---|---|---|
| Capacity and location | Typical unit | Your capacity, site and state |
| Figures | Illustrative | Built on current prices and quotations |
| Machinery suppliers and quotations | No | Yes |
| Market survey for your region | No | Yes |
| Bank or scheme format (PMEGP, term loan) | No | Yes |
| Use for a loan application | No | Yes |
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Caustic Soda project report: frequently asked questions
What is the caustic soda manufacturing plant cost in India?
A membrane cell plant of 100–200 MT per day needs roughly ₹150–350 crore, indicative, including land, building, electrolysers, power system and working capital margin. Our sample report models a 160 MT per day plant at ₹20,323 lakh, of which plant and machinery is ₹14,035 lakh. Your own cost depends on capacity, power arrangement and how much chlorine you process on site.
How much electricity does caustic soda production need?
A modern membrane cell plant uses roughly 2,300–2,600 kWh of power per tonne of caustic soda, indicative, counting the cells, rectifiers and evaporation. Power is the largest operating cost. In our sample report, power and fuel take 31.8% of sales, so a small change in the tariff moves profit and DSCR more than any other input.
What raw materials are needed to make caustic soda?
The main raw material is industrial salt, dissolved into brine. Soda ash and other chemicals remove calcium and magnesium, and the cells also need hydrochloric acid and demineralised water. In our sample report salt is 72% of raw material cost. Power is not counted as a raw material but costs far more than salt.
Is a caustic soda plant profitable?
In our illustrative sample, a 160 MT per day plant earns a 14% return on investment in Year 3. Break-even is at 40% of capacity and payback takes about 4.3 years. It takes chlorine and hydrogen revenue as nil. Real profit depends on your power tariff, the lye price in your region and whether you can sell or use the chlorine.
Can I start a small caustic soda flakes unit?
A stand-alone unit that buys lye and turns it into flakes is possible, but the margin is the difference between the lye and flake price, less fuel, packing and freight. That spread is often too thin to repay a term loan. Most flakes in India are made at integrated chlor-alkali plants, so a feasibility study should test the spread first.
Is BIS certification mandatory for caustic soda?
Yes. A Quality Control Order of the Department of Chemicals and Petrochemicals, notified on 3 April 2018, covers caustic soda. It must meet IS 252 and carry the BIS mark. This applies to caustic soda made in India and imported. Plan for the BIS licence and an in-house testing laboratory before commercial production starts.
Is the caustic soda project report PDF free, and can I use it for a bank loan?
The sample is free to view and download. It shows the format and depth of an NPCS report. Its figures are representative and not based on a real project, so it should not be submitted to a bank. For a loan or board approval, NPCS prepares a report for your capacity, site and power arrangement.
Sources and references
- Chemicals Quality Control Orders (Caustic Soda, IS 252:2013, S.O. 1468(E))Department of Chemicals and Petrochemicals, Government of India, checked Oct 2026
- Caustic Soda (IS 252:2013) quality control order noteBureau of Indian Standards, checked Oct 2026
- Lok Sabha Unstarred Question No. 3621: installed capacity and production of caustic sodaMinistry of Chemicals and Fertilizers, answered 21 March 2025, checked Oct 2026
- Categorisation of industrial sectors under Red as per CPCB criteriaState Pollution Control Board, Odisha, checked Oct 2026
- Standard terms of reference for a chlor-alkali project, item 4(d)PARIVESH, Ministry of Environment, Forest and Climate Change (SEAC Punjab, March 2024), checked Oct 2026
The NPCS project team, led by Ajay Kumar Gupta
This page and its sample report are prepared and reviewed by the NPCS project team, which has written techno-economic feasibility studies and detailed project reports since 1994.
Ajay Kumar Gupta founded Niir Project Consultancy Services (NPCS) and leads the organisation. With 40 years of experience in MSME project consulting, he has built the team that has delivered more than 28,000 project reports for clients worldwide, helping entrepreneurs plan and finance profitable manufacturing businesses.
- Published
- Last updated
- Next review
- Oct 2027
- Reviewed by
- NPCS project team
This page is reviewed every 12 months, or sooner when scheme limits, GST rates, BIS rules or pollution categories change. The sample report is illustrative: its figures are generated from industry-typical ratios for a unit of this size, checked so every statement balances, and are not taken from any client project.