Text B. Silicate Industry

The industry processing the natural compounds of silicon is called the silicate industry. It embraces the production of cement, glass and ceramics.

The production of ceramic goods is considered to be based on the property of clay when mixed with water to form putty from which articles can easily be moulded. When these articles are dried and then baked, that is, ignited at a high temperature, they become hard and their shape, no longer being softened by water.

In this way clay mixed with water and sand is moulded into bricks, which are then dried and baked. The materials used to make silicate bricks are white sand and slaked lime.

Cement Production. Cement is made from limestone and clay, or from their natural mixture marl; the materials roasted in cylindrical rotary kilns are charged into a slowly rotating kiln at its upper end and travel, mixing continuously, towards the lower end, while a current of hot gases, the products of the burning of fuel, flows in the opposite direction. During the period of their movement through the kiln the clay and the limestone react chemically, and the material emerging from the kiln in lumps of a caked mass is cement, which is then ground.

There are different types of cement: tamping cement for oil and gas wells; high alumina cement, which is very resistant to chemical attack, Portland cement, used in the construction of lightened structures with large spans; blast-furnace slag cement, coloured cement.

When cement is mixed with water, it forms mortar, which hardens, binding various objects, such as bricks or stones, very firmly. It is for this reason that cement is used widely as a binding material in large scale construction, including underwater construction. Cement is the most important component of concrete.

Glass Production. The initial materials for the production of ordinary glass are mainly soda Na₂CO₃, limestone CaCO₃, and sand SiO₂. A mixture of these substances is heated in a bath-shaped furnace.

When it cools, the liquid mass of glass does not become hard at once. At first it becomes viscous and readily assumes any shape. This property of glass is used in making various articles out of it.

3. Listen to the text again and answer the following questions:

1. What is the name of the industry processing the natural compounds of silicon?

2. What materials are used for making silicate bricks?

3. What are the initial materials for getting glass?

4. How do we get concrete?

5. What is the difference between cement and concrete?

4. Annotate the text either in English or in Ukrainian. Use the following phrases:

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At the beginning/end…

Further…

The author points out/stresses/informs/considers…

The text is useful and interesting for…

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