Pig iron is one of the most important materials produced in the metallurgical industry. It is generally produced from the iron ore by chemical reduction process of iron conducted in a large furnace called a blast furnace. The blast furnace is known to be the most complicated furnace system since it combines the operation of reducing the iron, melting the iron and slag and separating the latter from the iron. The furnace is a large cylinder lined with refractory material and has an opening at the top through which the charge consisting of coke, the iron ore and the flux enters the furnace. The charging material is carried up to the top of the furnace by means of special skip cars moving on an inclined hoist up to the top and empting the charge into the hopper. The charge must be porous enough to permit the uniform flow of air and gas through the material.
The action of the blast furnace consists in the chemical reaction between the solid charge and the rising column of gas in the furnace. The air necessary to support the combustion of the coke is blown into the furnace through the so-called tuyeres near the bottom of the furnace. To achieve a higher temperature in the melting zone the air is heated by means of stoves.
Once a blast furnace has been ignited it is operated continuously for many months. As raw material is consumed more and more carefully weighed portion of coke, the iron ore and the flux are added to maintain the needed volume of the material within the furnace. As the iron and slag are formed they drop to the hearth at the bottom of the furnace. Molten slag having a lower density floats on the iron and then it is tapped through the slag hole. Many of the impurities are collected and removed with limestone in the form of molten slag.
The iron is tapped from the furnace through the iron notch every 4 or 5 hours. The product obtained is a high-carbon iron called pig iron which is impure, brittle and not practically strong. Several classes of the blast furnace irons are produced depending on the use to which the iron is intended. Some pig irons are required for steel production in the open-hearth and Bessemer converter by reducing the carbon content and removing the impurities, others are used in foundry.
VIII. Прочтите текст и дайте краткое изложение его содержания на русском языке.
IX. Во II и V абзацах определите предложения, выражающие главную мысль.
X. Выберите предложения, которые отражают содержание текста (укажите их номера).
1. The acid open-hearth is used largely in foundry work.
2. The blast furnace is known to be the most complicated furnace system.
3. The furnace is a large cylinder lined with refractory material.
4. The body of the furnace is a cylindrical steel shell mounted on trunnions.
5. The iron tapped from the furnace through the iron notch every 4 or 5 hours.
6. The furnace is lined with iron oxide in the form of mill scale or ore.
7. Several classes of the blast furnace irons are produced depending on the use to which the iron is intended.
XI. Найдите в тексте ответы на следующие вопросы. Поставьте вопросы в правильной последовательности согласно содержанию текста.
1. What materials are to be charged into the furnace?
2. How is the charge carried up to the top of the furnace?
3. What is the blast furnace used for?
4. How can you characterize the pig iron produced in the blast furnace?
5. What does the blast furnace look like?
6. How is the iron reduced from the ore in the furnace?
XII. Заполните пропуски словами из текста:
(bottom; heated; iron notch; temperature; complicated; charging; slag)
1. The blast furnace is known to be the most ... furnace system.
2. The ... material is carried up to the top of the furnace.
3. To achieve a higher ... in the melting zone the air is ...... by means of stoves.
4. As the iron and ... are formed the drop to the hearth at the ...... of the furnace.
5. The iron is tapped from the furnace through the ... every 4 or 5 hours.
XIII. Переведите I, III, V абзацы текста.
XIV. Дополните следующие предложения в соответствии с содержанием текста.
1. To achieve a higher temperature ...
2. ... at the bottom of the furnace.
3. Several classes of the blast furnace ...
4. ... called a blast furnace.
5. The iron is tapped ...
6. ... air and gas through the material.
7. Once a blast furnace ...
8. ... through the slag hole.