PART 1: METALLURGY PROCESSES

Key terms and concepts.

A. READING

The science of metallurgy studies processes, which include the deriving of metals from their ores, or the condition in which they are found in nature; their purification, or their admixture with other metals; and finally their manufacture into shapes and forms usable in industry, with a view to their control and improvement, and the development of new metal mixtures or alloys and of new test methods. As the scope of metallurgy is so wide, the science of metallurgy may be divided into two parts: “Chemical Metallurgy” and “Physical Metallurgy”. The first part has such a name because it mainly deals with the chemical behaviour of metals during melting and refining processes. The second part mainly deals with the phisical behaviour of metals during shaping and treating operations and their behaviour in the service of man. There are two kinds of metals used in engineering-ferrous and non-ferrous. The former contain iron and the latter do not contain iron. Ferrous - metals are alloys of iron with carbon and some other elements. These alloys are called cast iron and steel. These two alloys are derived from pig iron, which is produced in a blast furnace in the form of pigs. The feed to the blast furnace is an iron ore. An ore is a crude containing a valuable constituent in such amounts as to constitute a promise of possible profit in extraction, treatment and sale. The valuable constituent of an ore is called mineral. A crude is a mixture of minerals in the form in which it occurs as a part of the earth’s crust. The associated worthless material is called gangue. In the blast furnace the gangue is converted into slag thereby separating from the pig iron. This metallurgical process is called smelting, because the separation is effected in a melt. The valuable metal product of smelting is usually differently named according to the metal involved, e.g. pig (iron), base bullion (lead), blister (copper), etc; the waste is slag. The fuels mostly used for melting metals are coke, coal, oil and gas.

Metals may occur in ores either in the native state (Cu, Ag, Au, Pt) or as salts or oxides (Fe₂O₃; CuS; PbCO₃).

In metallic ores the valuable mineral rarely the product desired by the consumers. The form in which the metal is required by the primary customers is a relatively pure substance. So the process of purification, usually involve, in order, ore-dressing, metallurgical extraction and chemical refining is a necessary step between delivery of ore at the mine exit and delivery of the metal to the customers. The valuable product of the ore-dressing treatment is called concentrate. The discarded waste is tailing. Ferrous metals are the main engineering material in the machine-building industry and one of the main materials in the construction industry, because of their high strength.

There are some applications of non-ferrous metals. They have better resistance to corrosion than steel and they are usually easier cast and worked. For most purpose the pure non-ferrous metals are too soft and other alloying elements have to be added to create particular physical properties as required by each application. For this purpose non-ferrous metals are mixed in various proportion to form different alloys, such as brasses, bronzes, duralumins. Their cost is considerably greater than that of carbon steel, but less that of some of the alloy steels.

EXERCISES:

I. Find in the texts the following topical words and phrases, explain what they mean, and add them to your Active Vocabulary:

ferrous metals, non-ferrous metals, brasses and bronzes, mechanical working processes,

metallurgy, cast iron and steel, chemical metallurgy, physical metallurgy, pig iron, an ore, mineral, concentrate, gangue, tailing, casting, alloying elements, slag, smelting, pig.

II. Write out from the texts the sentences or the parts of the sentences which contain the following words and expressions and translate them into Russian:

works, iron, native state, ore-dressing, soft, carbon steel, branches of industry, carbon, harmful impurities, deriving of metals, a furnace, to undergo heat treatment, electrical and thermal conductivity, billets, properties, long service life, alloys, mill rolls.

III. Answer the following questions:

1. What parts may the science of metallurgy be divided into?

2. What is the difference between ferrous and non-ferrous metals?

3. What is quality of metal works determined by?

4. What is it necessary to do to make steel from cast iron?

5. What non-ferrous metals are used most frequently?

6. What metals are produced from pig iron?

7. What are ferrous metals?

8. What does the science of metallurgy study?

9. How do we call processes, when metal is shaped by pressure?

10. What is a crude?

11. What does the right choice of metal provide?

12. Why sometimes are non-ferrous metals used instead of ferrous metals?

13. What are coke, coal, oil and gas used for in metallurgy?

14. What purpose are non-ferrous metals mixed for?

15. Because of what are ferrous metals the main engineering material?

B. TRANSLATION

EXERCISES:

I. Before translating the text, find in it the sentences in which you would be able to use the following topical words and expressions:

welding, soldering and brazing, periodic table, shops and work bays, to give the metal some coating, opacity, atom bonds, density, noble and rare metals, solid and liquid state, dry metallurgy, to leach, to derive from solution, hydrometallurgy.

II. Read the text again, find in it the information about the following questions, and answer them using the topical words and phrases:

1. What shops can modern machine-building plants have?

2. What kinds of treatment and mechanical working of metals does metallurgy study?

3. What metals are widely used in the pure state?

4. How can non-ferrous metals be divided?

5. Non-ferrous metals have some drawbacks. What are they?

6. What is dry- and hydro-metallurgy?

7. What is the most widely used method of metal making?

III. Now translate the text in writing. Use as many topical words and phrases as you can:

К металлургии относятся производственные процессы обработки добытых руд, процессы получения металлов, очистки металлов от нежелательных примесей (рафинирование), производства металлических сплавов, термическая (тепловая) и химико-термическая обработка металлов и сплавов, обработка металлов давлением, литьем, сварка и пайка металлов, покрытие металла слоем другого металла.

Многие из названных металлургических процессов стали выполняться не в собственно металлургической промышленности, а вошли в состав различных отраслей машиностроения и строительной индустрии. Современные машиностроительные заводы могут иметь сталеплавильные, литейные, прокатные, кузнечные, штамповочные, сварочные, термические, гальванические цехи или участки в составе механических цехов.

К металлам относят большинство химических элементов периодической системы Менделеева. В твердом и жидком состоянии они отличаются от элементов - неметаллов - характерными металлическими межатомными связями. Такие связи обуславливают электро- и теплопроводность металлов, их прочность; металлам свойственны также пластичность и ковкость, непрозрачность и металлический блеск.

Некоторые металлы находят широкое применение в технически чистом виде, т.е. с малым содержанием примесей, например железо, медь и алюминий в электро- и радиотехнике.

Несравненно шире и разнообразнее применение металлических сплавов.

Важнейшим промышленным металлом является железо (Fe), которое в чистом виде и в сплавах с углеродом (С) и другими элементами относят к группе черных металлов.

Все остальные металлы и их сплавы относятся к группе цветных металлов; их принято делить на легкие (плотность до 3 г/см³) и тяжелые. Различают также благородные и редкие металлы.

Из цветных металлов важное промышленное значение имеют медь Cu, алюминий Al, магний Mg, свинец Pb, цинк Zn, олово Sn, титан Ti. Но стоимость цветных металлов по сравнению с черными очень высока, поэтому во всех случаях, когда это допустимо, их стараются заменить черными металлами.

Кроме перечисленных промышленное применение имеют также следующие цветные металлы: хром Cr, никель Ni, марганец Mn, молибден Mo, кобальт Co, ванадий V, вольфрам W, цирконий Zr, тантал Ta, ниобий Nb, рений Re, индий In и полупроводники - германий Ge, селен Se, теллур Te.

В соответствии с подразделением металлов и исходных руд различают металлургию черных и цветных металлов. В зависимости от вида энергии, используемой при основных процессах, различают пирометаллургию и гидрометаллургию.

В пирометаллургии металлы и сплавы получают и рафинируют при сжигании топлива.

В гидрометаллургии металлы получают из руд путем выщелачивания и выделения из растворов без нагрева до высокой температуры.

Наиболее распространенным способом получения металлов и сплавов является плавка, основанная на сжигании топлива в печах.