Sodium Silicate

Product Code 31337
Quality and Standards IS 381:1995
IS 6773:1978
IS 9601:1980
Production Capacity Quantity: 2600 tonnes (per annum)
Value : Rs. 1,23,50,000 (per annum)
Uploaded on 27th December 2006


Sodium Silicate is a colourless compound of oxides of sodium and silica. It has a range of chemical formula varying in sodium oxide (Na2O) and silicon dioxide or silica (SiO2 ) contents or ratios. It is soluble in water and it is prepared by reacting silica sand and sodium carbonate at a high temperature ranging from 1200 to 1400oC. Aqueous solution of sodium silicate is called water glass.

Sodium silicates are produced in the form of a variety of compounds ranging from Na2O.4SiO2 to 2Na2O.SiO2 by properly proportioning the reactants. Sodium silicates varying in ratio from Na2O.1.6SiO2 to Na2O.4SiO2 are known as colloidal silicates. These are sold as 20% to 50% aqueous solutions called water glass.

Sodium metasilicate has the ratio of Na2O.SiO2 and is a definite crystalline compound, which forms various hydrates. Substances having higher sodium oxide content are sodium squisilicate 1.5Na2O. SiO2 and sodium orthosilicate 2Na2O. SiO2 . The more alkaline silicates including sodium metasilicate (Na2O.SiO2 ) are crystalline materials with definite structures and characteristic properties. These are used chiefly as cleaners and detergents. The more siliceous sodium silicates are glasses, typical non-crystalline solid solutions, which are important mostly for their adhesive and binding properties.

Market Potential

Sodium Silicate is used in soaps detergents and in the manufacture of silica gel. It is used as a cement, binder, filler and adhesive. And also used as a wall coating, in concrete, fire proofing material and as a sealant. It is also used to preserve eggs and wood. Sodium Silicate also finds use in textile and pharmaceutical industries. Neutral sodium silicate in liquid form is suitable for use in pharmaceutical and toilet preparations.

Sodium silicates of certain ratios are used for application over concrete floors for hardening making dustless concrete floors and protecting pervious building materials against the effects of moisture. Sodium silicate is also used in foundries and welding electrode industries. In ceramic industries, sodium silicate is used as a deflocculant in the preparation of casting slips for keeping solid particles in suspension without settling. Sodium silicate is used in refractories industries as an air-setting bond for manufacturing refractory cements and mortars. In vitreous enamel industries, it is used for cleaning the metal, known as pickling, prior to enamelling.

Basis and Presumptions

Efficiency : Since manufacture of Sodium silicate is a continuous process, it is envisaged that the unit will run 3 shifts a day continuously for 25 days in a month or 300 days in a year. 75 percent efficiency of machinery and manpower is considered.

Time Period : Full capacity utilization is expected to be achieved within 12 months of commencement of commercial production.

Labour Wages : Minimum applicable wages is considered. Interest Rate: An interest rate of 12% per annum on the total capital investment has been considered. Margin Money: Promoter is expected to bring in one-third of the total capital investment.

Pay Back Period : The project will have a payback period of about 4 years. Land and Construction Costs: Land cost is considered at Rs. 3000 per square metre, and Construction cost for office and stores at Rs. 6000 per square metre, and work shed at Rs. 4000 per square metre.

Implementation Schedule


Period(in months)

Preparation of the project report, selection of site, provisional registration from DIC, availability of finance 3
Construction of building, procurement of machinery and equipment availability of electrical power 4
Erection and Commissioning, recruitment of manpower, trial runs and commencement of commercial production 2
Total implementation period 9

Technical Aspects

Process of Manufacture

Silica sand and Sodium carbonate are the two principal raw materials used in the manufacture of sodium silicate. The proportions of these two raw materials will vary depending on the ratio of Na2O and SiO2 required in the final product. Processed quartz with a particle size distribution of –20 and +80 BS Sieve can also be used in place of natural silica sand. Sodium carbonate, also called soda ash, is available in two forms: dense and light. Only dense variety of sodium carbonate is used for manufacture of sodium silicate.

The raw materials are charged from a charging end, which is called a dog house, into a continuous glass-melting furnace operated at 1200o C to 1400o C. The exact melting temperature will depend on the batch constituents. There will be weight loss of approximately 10% in the weight of the charge to the weight of finished fused melt drawn from the furnace due to loss of gases and volatilization of alkali oxides.

The fused melt is drawn from the discharging end of the furnace continuously or periodically as a thin stream. This melt will be solidified by passage into a moving chilled conveyor of steel moulds, in which the melt cools to a semi-transparent solid.

If the hot melt is sprayed with a stream of cold water, it is shattered into fragments. The fragments are either charged into grinding and screening equipment to yield solid sodium silicate (granular) or are passed into a rotary dissolver. In the rotary dissolver, the solid material is dissolved by superheated (80 psi) steam.

Alternatively, the fused melt is directly passed into water, in which it is dissolved with steam. The resulting solution is clarified by settling in a tank and is adjusted to the desired specific gravity. Specific gravity of sodium silicates range from 22 to 69 Be with 40 Be being the most common.

Dry, powdered sodium silicates may be produced by taking liquors of proper specific gravity and forcing them through a very fine opening into a solidification chamber. The chamber is swept by a rapid current of cold air, which carries off the moisture. The desired sodium silicate is obtained by varying the ratio of the raw materials charged as well as the working up of proper solution.

Quality Control and Standards

  • Indian Standard Specifications The Bureau of Indian Standards has published the following Indian Standard Specifications for Sodium silicate based on its use in various industries:

    i. IS 381:1995: Sodium silicate (Second Revision).
    ii. IS 6773:1978: Sodium silicate for use in foundries (First Revision) Re-affirmed 1991.
    iii. IS 9601:1980: Sodium silicate for cosmetic industries (Amendment No. 1) Re-affirmed 1991.
    iv. IS 14212:1995: Methods of test for sodium silicate and potassium silicates.
  • Grades and Types of Sodium Silicate

According to IS 381, both the solid and liquid form of sodium silicate are of two grades: (a) Neutral, and (b) Alkaline.

Sodium Silicate

Further, the above standard also categorizes the liquid form of sodium silicates into the following types: Liquid, neutral sodium silicates are of two types:

i. Type 1: For use in pharmaceutical and toilet preparations.

ii. Type 2: For use as an adhesive and other purposes.

Liquid, alkaline sodium silicates are of three types:

Type 1, Type 2, and Type 3: For use in soap, detergent, textile, welding electrode and cement industries.

Quality Requirements

The quality requirements according to the IS 381 are as follows:

Neutral sodium silicate shall be clear, free from dirt and other visible impurities. Liquid sodium silicate shall be thick, viscous, translucent mass of water white or slightly grey colour. Solid sodium silicate shall be in the form of glassy lumps of pale grey or green colour. The particle size shall be as mutually agreed to between the purchaser and the supplier to meet the special requirements. Other quality requirements for sodium silicate viz., matter insoluble in water, relative density, total soluble silicates, ratio of total alkalinity to total soluble silica, loss in mass on ignition, viscosity and limits for iron, chloride and sulphate contents are given in the IS 381.


The materials shall be packed in airtight mild steel (MS) drums of capacity as mutually agreed to between the purchaser and the supplier.


Each package shall be legibly and indelibly marked with name and grade of the material, source of manufacture, gross and net mass, year of manufacture and lot number.

Production Capacity (per annum)

Quantity 4000 tonnes
Value Rs. 4,19,60,000
Motive Power 60 HP.

Pollution Control

Both raw materials, silica sand and sodium carbonate are purchased in the ready to use powder form. Only mixing of these materials in appropriate proportions is done in the batch house in the plant. Hence, dust collectors and exhaust systems are recommended in the batch house. In the melting operation, chimney of sufficient height, say 60 to 75 feet, is recommended to exit the gases of combustion, carbon dioxide from the soda ash and also volatilization of alkali oxides.

Energy Conservation

Modern glass tank furnace is recommended using furnace oil, LDO or gas firing systems. Combustion systems, for example, burners, blowers, preheating of fuel will depend on the fuel selected. Care should be taken in selecting the type and design of the furnace, refractories to be used for construction of the furnace, proper thermal insulation of the furnace walls and crown. All these factors have a bearing on the thermal efficiency of the furnace and energy conservation achieved in the melting operation. Melting operation constitutes a significant cost factor in production of sodium silicate.

Financial Aspects

A.Fixed Capital

Land and Building


Sq. Meters

Rate (Rs.)

Value (Rs.)

Land 4000 3000 1200000
Built Area
Office and Stores 100 6000 600000
Working Shed 400 4000 1600000
Raw Material Storage 400 4000 1600000
Finished goods Storage 500 500 2000000
Total 7000000

Machinery and Equipments


Imp/ Ind.

Qty. (Nos.)

Rate (Rs.)

Value (Rs.)

Production Unit
Glass Tank Furnace, drawing capacity: 5 tonnes per day, melting area: 6 square metres Ind. 1 2000000 20,00,000
Chimney of 60 to 75 feet height Ind. 1 300000 3,00,000
Combustion equipment for furnace oil firing, including burners, blowers, oil pipelines, preheating systems, etc. Ind. 1 set 700000 7,00,000
Oil storage tank, Capacity: 10 kilolitres and pumps and piping Ind. Ind. 300000 3,00,000
Dissolving tanks and agitators Ind. 2 sets 400000 8,00,000
Bore well with pump set Ind. 1 400000 400000
Portable combustion analyzer Imp 1 800000 8,00,000
Mild steel barrels of 200 lit capacity Ind 1000 1000 10,00,000
Cost of laboratory instruments        
Pollution Control Devices Ind. 1   7,00,000
Cost of erection, installation and electrification, at 10% of the above Ind. 1   7,00,000
Cost of office equipment, furniture, Ind. 1   3,00,000
Total       83,00,000

Pre-Operative Expenses


Project report cost, non-refundable deposits, etc 5,00,000
Total Fixed Capital 1,58,00,000

B. Working Capital (Per Month)

Personnel (per month)



Salary / (Rs.)


Administration and Supervisory personnel
Manager 1 15,000 15,000
Supervisors 2 10,000 20,000
Salesman 1 10,000 10,000
Accountant 1 10,000 10,000
Clerk 1 6,000 6,000
Watchman 4 3,500 14,000
Technical-Skilled and Semi or Unskilled Personnel
Skilled workers 6 5,000 30,000
Un-skilled workers 15 3,000 45,000
Perquisites: @ 22% of the above     30,000
Total 1,80,000

Raw Materials (per month)


Imp/ Ind.



Rate (Rs.)

Value (Rs.)

Soda ash Ind. 70 Tonnes 13000 144000
Silica sand Ind. 123 Tonnes 4000 7200
Chemicals Ind. LS     9150
Total 14,48,000

Utilities (per month)




Rate (Rs.)

Value (Rs.)

Furnace oil 45 Kiloliters 18000 18000
Electrical power 12500 kWh 4 50,000
Water 4000 Kilolitres 2 8,000
Total 8,68,000

Other Contingent Expenses (per month)


Postage and stationery 5000
Telephone 10000
Consumable stores 25000
Repairs and maintenance 11500
Transport charges 20000
Advertisement and publicity 25000
Insurance 10000
Taxes 5000
Sales expenses 11500
Miscellaneous expenses 10000
Total 133000

Total Recurring Expenditure (per month) : 26,29,000

Total Working Capital (on 3 months basis) : 78,87,000

Total Capital Investment : 2,36,87,000

Machinery Utilization

Machinery utilization of 75 percent has been considered in the project.

Financial Analysis

Cost of Production (per year)



Total recurring cost 3,15,48,000
Depreciation on building @ 5% 1,16,000
Depreciation on Machinery and Equipment @ 10% 5,70,000
Depreciation on Furnace @ 20% 4,00,000
Interest on capital investment @ 12% 28,42,000
Depreciation on office equipments and furniture @ 20% 60,000
Total 3,55,36,000

Sales Turnover (per year)




Rate (Rs.)

Value (Rs.)

Sodium silicate liquid 4000 Tonnes 10490 4,19,60,000

Net Profit Before Tax

Rs. 4,19,60,000 - 3,55,36,000 Rs. 64,24,000

Net Profit (per annum)

  Turnover – Cost of Production
  22550000 – 21280124

Net Profit Ratio


Net Profit per year x 100

Sales Turnover per year

64,24,000 x 100


Rate of Return


Net Profit per year × 100

Total Capital Investment

69,94,000 × 100


Break-even Point

Fixed Cost (per year)


Total depreciation 11,46,000
Interest on total capital investment 418350
Insurance 1,20,000
40% of Salaries and wages 8,64,000
40% other contingent expenses 638,000
Total 56,10,000



Fixed Cost ×100

Fixed Cost + Not Profit

56,10,000 x 100

56,10,000 + 64,24,000

56,10,000 x 100




Addresses of Machinery Suppliers

  • M/s. Glass Plant Construction Cor. 13, Km Stone,
    Chandigarh-Ambala Road,
    P.O. Dhankoli, Via Mubarakpur,
    District. Patiala, (Punjab)
  • M/s. United Works Pvt. Limited
    7-8, Mahalakhmi Bridge,
    Mumbai-400 011
  • M/s. Maul Eastern Limited
    157, Maker Chambers-VI,
    14th Floor, 220, Nariman Point,
    Mumbai-400 021

  • Raw Material Suppliers

  • M/s. Gujarath Heavy Chemicals Limited
    B-309, 7th Main,
    Peanya Industrial Area,
    Bangalore-560 058
  • M/s. Bangalore Mines and Minerals Products
    21, Tavarakere Cross,
    Bangalore–560 029
  • M/s. Sanjay Minerals Private Limited
    30-A, 2nd Phase,
    Peenya Industrial Area,
    Bangalore–560 058

For further information please contact

Information Manager
TIMEIS Project