1. Product Description: Sodium silicates popularly called water glass or soluble water are generally classified according to their Sio2 :Na2o ratio which varies between 0.5 and 4 and with various proportions of water. Sodium silicates serve as joining, cleaning, bending and cementing agents in many industries. Large scale applications of the silicates are in the chemical, soap, adhesive and cement industries. Large amounts of the silicates are employed as adhesives in the manufacture of glass products, veneer products, fireboards and corrugated paperboard. In their applications, the silicates are used as syrupy solutions which set by loss of moisture. Silicates are used as fire-resisting binder for asbestos and other similar insulating materials as a binding material in coal briquettes, in paints for plaster, stucco and cement. They are also employed in the preparation of cores and moulds for casting molten metals.
2. Rationale: As stated above, sodium silicates are important inputs for many branches of industries. Though in a modest scale, many industries which use sodium silicates are established in our country and more will be established in the future. Among the existing industries which use sodium silicate, the most important ones are the cement factories, the glass factory, the fire-board and the corrugated paper board factories which are located in different parts of the country. While there are a number of factories which use sodium silicates, there is no any single plant which produces these products. All the sodium silicates needs of the country are imported. One basic objective of industrial development for any country or region is to substitute imports by domestic production. And this must be particularly true when the product to be produced at home is used as inputs for other industries.
3. Market Potential: Sodium silicates are used as inputs for many types of factories and they have a wide variety of applications in other fields also. The existing demand for sodium silicates by various users will create sufficient market for at least one sodium silicates factory in the country. The factory could be established in the Amhara Region and the product could be distributed at the national level.
4. Source of Raw Material: The main raw materials are soda ash, sand, gas, and water. Except gas, the other raw materials can be obtained for domestic sources.
5. Process & Technology: Sodium silicates are prepared commercially by continuous feeding of a mixture of pure sand and soda ash into oil or gas fired glass melting furnaces and heating the mixture up to 1450oC. The fused silicate mass is removed from the furnaces by means of bucket elevators and is transported to storage bins where it is cooled and dried to obtain anhydrous sodium silicate. The hydrates are obtained by either treating the anhydrous salt with steam at a pressure of 5 atmospheres at 140oC in autoclave or by passing the molten silicate directly into water in a slowly rotating drum. The diluted solution is settled in settling tanks, passed through filter presses and the clear liquid stored in storage tanks. The hydrates in solid state are prepared by evaporating seeded solutions of sodium silicate in multiple effect evaporators under regulated conditions. Main machinery required includes furnace, conveyer, rotary dissolver, settler and boiler.
6. Estimated Investment: The recommended capacity for an economically viable unit would be of the order of 3 tons per day. The estimated investment for this plant capacity is:
§ Buildings/Shades 530 m2 at Birr 2000/m2= Birr 1,100,000
§ Plant and Machinery = Birr 1,200,000
§ Wording Capital = Birr 600,000
2,900,000
7. Benefits: As stated earlier, sodium silicates are used as inputs in the cement, chemical, soap, glass, wood paper board, etc. industries. The domestic production of sodium silicates promotes the development of the above industries. Other benefits include utilization of domestic natural resource such as soda ash, introduce new skills and technology to the Region, saves foreign exchange and regional financial resources.
8. Location: Near the site where the main raw material is to be found.