Read the text and translate it into Ukrainian (Russian) with the help of the vocabulary listed above. Portland Cement Manufacturing

Portland cement is manufactured from lime-bearing materials, usually limestone, together with clays, shales, or blast-furnace slag containing alumina and silica, in the approximate proportions of 60 percent lime, 19 percent silica, and 8 percent alumina, 5 percent iron, 5 percent magnesia, and 3 percent sulfur trioxide. Some rocks, called cement rocks, are naturally composed of these elements in approximately suitable proportions and can be made into cement without the use of large quantities of other raw materials.

In the manufacture of cement the raw materials are ground together, the mixture is heated until it fuses into a clinker, and the clinker is ground into a fine powder.

The heating is usually accomplished in rotary kilns more than 150 m (500 ft) long and 3.7 m (12 ft) or more in diameter. The kilns are slightly tilted from the horizontal, and the raw material is introduced at the upper end, either in the form of a dry rock powder or as a wet paste composed of ground-up rock and water. As the charge progresses down through the kiln, it is dried and heated by the hot gases from a flame at the lower end. As it comes nearer the flame, carbon dioxide is driven off, and in the area of the flame itself the charge is fused at temperatures between 1540° and 1600° C (2800° and 2900° F).

The material takes approximately 6 hours to pass from one end of the kiln to the other. After it leaves the kiln, the clinker is cooled quickly and ground, and then conveyed by a blower to packing machinery or storage silos. The amount thus produced is so fine in texture that 90 percent or more of its particles will pass through a sieve with 6200 openings per square centimeter.

By varying the percentage of its normal components or adding others, portland cement can be given various characteristics, such as rapid hardening, low heat during hydration, and resistance to alkalis. Rapid-hardening cements, sometimes called high-early-strength cements, are made by increasing the proportion of tricalcium silicate or by finer grinding, so that up to 99.5 percent will pass through a screen with 16,370 openings per sq cm. Some of these cements will harden as much in a day as ordinary cement does in a month. They produce much heat during hydration, however, which makes them unsuitable for large structures where such heat may cause cracks. Special low-heat cements, which usually have a large proportion of dicalcium silicate, are generally used for massive pourings.

Task 5

Restore the sentences. Consult the text above.

1….ground together.

2….heated .

3….fuse into a clinker.

4….ground into a fine powder.

5. The material takes about 6 hours to pass….

6….cooled quickly and ground.

7….conveyed by a blower to….

8. 90 percent or more of cement particles can pass through….

9. By varying the percentage of components or adding others….

Task 6

Answer the following questions using the information from the text.

1. What materials is Portland cement manufactured from?

2. What rocks are naturally composed of lime-bearing materials?

3. What are the necessary stages in the manufacture of cement?

4. Where are the ingredients for the manufacture of cement heated?

5. In what form is the raw material for the manufacture of cement charged into the kiln?

6. How is the material for the manufacture of cement heated?

7. How long does it take the raw material to pass from one end of the kiln to the other?

8. At what temperatures does the raw material fuse into a clinker?

9. How small are the particles of the cement powder?

10. How can portland cement be given various characteristics?

11. Why are rapid-hardening cements unsuitable for large structures?

12. What types of cements are generally used for massive pourings?

Task 7

Fill in the gaps with prepositions if necessary. Consult the text above.

1. Portland cement is manufactured from lime-bearing materials …. the approximate proportions .… 60 percent …. lime, 19 percent …. silica, and 8 percent …. alumina, 5 percent …. iron, 5 percent …. magnesia, and 3 percent ….. sulfur trioxide.

2. .… the manufacture …. cement the raw material is heated until it fuses …. a clinker, and the clinker is ground .… a fine powder.

3. The kilns used …. cement manufacturing are slightly tilted …. the horizontal.

4. The raw material is introduced …. the upper end …. the kiln.

5. In the kiln, the raw material is dried and heated …. the hot gases …. a flame .… the lower end.

6. The raw material …. cement manufacture fuses .… a clinker .… temperatures …. 1540° and 1600° C.

7. After the clinker has been cooled and ground, it is conveyed …. a blower …. packing machinery or storage silos.

8. Some rapid-hardening cements harden as much .… a day as ordinary cement does .… a month.

Task 8

Read the following figures. Note that in English a full stop is used for the decimals, not a comma. Figures after the decimal point must be read separately.

Examples

3.77 – three point seven seven

0.01 – nought (zero) point nought (zero) one

10.56; 74.96; 13.18; 6.89; 0.05; 200.96; 18.09; 63.78; 45.69; 51.39.

Task 9

Transform the following sentences according to the model. Translate the sentences into Ukrainian (Russian).

Model

The raw material is charged at the upper end of the kiln.  The raw material is now being charged at the upper end of the kiln.

1. The raw materials are ground together.

2. The raw material for the manufacture of cement is charged into the kiln.

3. The mixture is heated to fuse into a clinker.

4. The clinker is ground into a fine powder.

5. The clinker is cooled.

6. The clinker is conveyed to the storage silo.

Task 10

Translate into English the following word-combinations.

1. Швидкотверднучий, швидкотверднучий цемент.

2. Сировина, засипання сировини, засипання сировини у піч, завантажувати сировину, завантажувати сировину в піч.

3. Вапняк; матеріал, що містить вапняк.

4. Фільтр, сітчастий фільтр.

5. Виробляти цемент, виробництво цементу.

6. Сірка, триоксид сірки, містити триоксид сірки.

7. Нижній кінець, верхній кінець.

8. Дрібнозернистий, дрібнозерниста структура, мати дрібнозернисту структуру.

9. Здрібнений, здрібнений камінь.

10. Подрібнювати, подрібнювати в порошок.

11. Пропорція, змінити пропорцію, змінити пропорцію двокальцієвого силікату, збільшити пропорцію трикальцієвого силікату.

12. Лугостійкий, бути лугостійким.

13. Непридатний, бути непридатним.

Task 11

Translate into English using the active vocabulary and the text above.

Зараз ви бачите, що вихідні матеріали для виробництва цементу завантажуються у піч.

Тепер вони нагріваються. У такий спосіб ми одержуємо цементний клінкер. А зараз цементний клінкер подрібнюється у порошок.

Тепер ви бачите, що клінкер охолоджується. А зараз він роздрібнюється. Порошок має бути дуже дрібним.

Зараз порошок просівається крізь сітчастий фільтр. Можна змінювати кількість і процентне співвідношення вихідних матеріалів і одержувати портланд-цемент з різними властивостями.

Task 12

Your are a portland-cement production foreman. Explain how you manufacture portland-cement using the information in the text above.