English Reader for Technical Students. Учебное пособие

Assignments:

1.Describe properties of the metals of Ib, IIb, IIIb and IYb groups.

2.Prepare a report on the following topic: Great usefulness of metals and their alloys to man.

2.2. Copper

Copper is found native and some of its ores are easily reduced, copper and bronze have therefore been used from very early times. The Romans obtained copper from Cyprus. They called it cyrium and subsequently cuprum; hence the symbol Cu. Copper ores are found to be widely distributed throughout the world. Copper, when newly mined and deposited in electrolysis or freshly reduced from the oxide, is salmon-pink in colour, but the metal soon tarnished, the light transmitted through copper leaf is green. Most cupric compounds are blue or green, the solution being also blue or green. The metal is malleable and ductile, and can therefore be hammered out into thin sheets or drawn into wire. Just below the melting point, however, it becomes brittle. Copper being a very good conductor of heat is common knowledge; therefore it is widely used on this account. Copper is stable in dry air, but if it were exposed in moist air for a long time, it would become covered with a green coating. On heating in dry air, copper becomes covered with a black film of cupric oxide and if this film is scratched, a red film of cuprous oxide is found under the black. The metal is without action on water and at white heat is only slightly attacked by steam. If copper is heated with concentrated sulfuric acid it dissolves and sulfur dioxide is liberated. The oxidizing agent here is sulfuric acid. Copper forms two series of compounds, distinguished as cuprous and cupric, respectively. Cuprus oxide is used in the manufacture of ruby glass and cupric oxide is used in the manufacture of blue glass. Copper sulfate is the most common cupric compound. It can be made by dissolving cupric acid and crystallizing.

6)cuprous oxide is used in the manufacture of ... f) stable

7)cupric oxide is used in the manufacture of ... g) cyrium.

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Exercise 2. Choose the right answer:

4) On heating in dry air, copper becomes covered with ...

a)a black film of cuprous oxide

b)a red film of cuprous oxide

c)a black film of cupric oxide.

Exercise 3. Are these statements true or false?

1.Copper is found native.

2.Copper ores are found to be widely distributed throughout the world.

3.When freshly reduced from the oxide copper is green in colour.

4.Most cupric compounds are red.

5.Copper is not malleable, and cannot therefore be hammered out into thin sheets.

6.Copper can be drawn into wire.

7.Just below the melting point copper becomes brittle.

8.Copper is not stable in dry air.

9.On heating in dry air, copper becomes covered with a black film of cupric oxide.

10.Cuprous oxide is used in the manufacture of blue glass.

Exercise 4. Answer the questions:

1.Why have copper and bronze been used from very early times?

2.Where did the Romans obtain copper from?

3.How did they call it?

4.What colour is a newly mined copper?

5.What colour are the most cupric compounds?

6.Name the properties of copper.

7.When does copper become brittle?

8.Why is copper widely used?

9.What would it happen with copper if it were exposed in moist air for a long time?

10.What series of compounds does copper form?

11.Where is cuprous oxide used?

12.What is the most common cupric compound?

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Exercise 5. Look at the words below. Say which adjectives you can use with given nouns. Cross out those which you think are not correct: copper: native, reddish, salmon-pink, green, blue, brittle, liquid, malleable, ductile, light, heavy, expensive, stable

oxide: cupric, negative, reacting, blue, red, black, sulfuric, cuprous, white, ruby, cupric

compound: ruby, radioactive, cuprous, ordinary, common, cupric, oxidizing, blue, ductile, green, sulfuric, pink.

Do you know that:

One of the famous Dead Sea Scrolls found in Israel is made of copper instead of fragile animal skins. The scroll contains clues to a still undiscovered treasure.

Archeologists have recovered a portion of water plumbing system from the Pyramid of Cheops in Egypt. After 5000 years, the copper tubing was still in serviceable condition.

A copper frying pan at the university of Pennsylvania’s museum has been dated to be more than 50 centuries old.

While the Greeks during Aristotle’s era were familiar with brass, it was not until Augustus’ Imperial Rome that brass became abundantly used. In South America, the pre-Columbian Maya, Aztec, and Inca civilizations exploited copper, as well as gold and silver. During the Middle Ages, copper and bronze flourished in China, India, and Japan.

When Columbus sailed to America, his ships (Nina, Pinta and Santa Maria) had copper skin below the water line. The copper sheathing extended hull life and protected against barnacles and types of biofouling. Today, most sea-going vessels use a copper based paint for hull protection.

Archaeological evidence indicates that copper was used as far back as 10,000 years ago in western Asia. During the prehistoric Chalcolithic Period, societies discovered how to extract and use copper to produce ornaments and implements. As early as the 3d – 4th Millennium B.C., copper was actively extracted from Spain’s Huelva region. Around 2500 B.C., the discovery of useful properties of copper-tin alloys led to the Bronze Age.

Assignments:

1.Say what you think of these facts and whether you consider copper one of the most important metals in the lives of ancient people.

2.What another interesting facts do you know?

3.Prepare a report on the following topic: A history of copper.

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2.3. Zinc

The production of zinc occurred much later than that of the other common metals. Whilst copper was smelted from its ores probably about 5000 B.C., lead was produced about 4000 B.C. and iron about 2000 B.C., zinc does not seem to have been available on a commercial scale until the 14th century.

As a metal zinc was certainly known before this time. Brass, an alloy of zinc and copper, was produced by the Romans as early as 200 B.C., but the method they used involved the heating together in crucibles of copper, zinc oxide and carbon. The zinc formed by reduction of the oxide was absorbed immediately in the copper and was not produced as a separate phase.

Most lead ores contain zinc and zinc is not found native. Zinc is a white crystalline metal melting at 419.6 degrees and boiling at 907 degrees; being a very reactive metal, zinc burns in air when strongly heated, forming the oxide. In moist air the metal becomes coated with the layer of basic zinc carbonate. The metal will be attacked by the steam when heated in it.

When very pure, zinc is brittle at ordinary temperatures but malleable above 100 degrees and can then be readily rolled. When alloyed with 4 per cent aluminium its strength and hardness is increased considerably. Small additions of copper and titanium appreciably improve the creep resistance of rolled sheet and the use of this material is growing. With additions of 20 – 22 per cent aluminium, superplasticity can be developed, the alloys produced flowing readily at temperatures of 220 degrees under vacuum.

One of the most useful characteristics of zinc is its resistance to atmospheric corrosion, one of its main applications thus being for the protection of steelwork. The electro-negative character of zinc also leads to its use in considerable quantities in dry batteries.

As with most metals, the zinc industry relies on the fortunate fact that at certain spots on the earth’s surface a high degree of concentration of the metal has taken place to form workable ore deposits. With present techniques the dependence of the zinc industry on the discovery and exploitation of these ores bodies is complete. Their occurrence in the earth’s surface is almost certainly limited and their availability in sufficient numbers in the future must be a matter of some concern since the demand for zinc has been growing at a considerable rate.

Exercise 1. Look through two columns of the words. Find the synonyms and translate them:

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Exercise 2. Find English equivalents to the following Russian words

Exercise 3. Group the following words into sentences and translate them:

1.a; silvery; relatively; melting; zinc; metal; a; low; with; white; point; is.

2.group; the; Table; zinc; constitute; IIb; cadmium; of; mercury; Periodic; and.

3.five; we; metals; today; more; know; sixty; than.

4.with; layer; iron; often; of; is; a; coated; zinc; protective.

Exercise 4. Fill in the blanks with prepositions (by; above; of; in; at; with):

1.Zinc is a white crystalline metal melting ... 419.6 degrees.

2.The production ... zinc occurred much later than that of the other common metals.

3.Brass was produced ... the Romans.

4. ... moist air zinc becomes coated ... the layer of basic zinc carbonate. 5. Zinc is malleable ... 100 degrees.

Exercise 5. Are these statements true or false?

1.Brass is an alloy of zinc and lead.

2.The production of zinc occurred much earlier than that of the other common metals.

3.Zinc is not found native.

4.The melting point of zinc is 907 degrees.

5.Zinc burns in air when strongly heated.

6.When very pure, zinc is malleable.

7.One of the main applications of zinc is for the protection of steelwork.

8.Zinc is also used in dry batteries.

9.Most copper ores contain zinc.

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Exercise 6. Answer the questions:

1.When did the production of zinc occur?

2.What alloy was produced by the Romans and when?

3.Describe the method of producing brass by the Romans.

4.What are the properties of zinc?

5.What are the most useful characteristics of zinc?

6.What does the zinc industry rely on?

Do you know that:

Zinc coatings are one of the best methods for the protection of steelwork against corrosion. There are two reasons for this, the first being that zinc is itself resistant to normal atmospheric corrosion – instances have been recorded where zinc roofing sheet has given service for over 100 years. In most atmospheric conditions the rate of attack on zinc is only 3 – 10 per cent that on steel, and this is due mainly to the grey impermeable film which forms over surface of the metal exposed to air. This resists further attack, although in industrial atmospheres containing sulphur dioxide the film is less stable because it consists largely of basic zinc carbonate which reacts with the sulphurous acid. Thus, a coating of metallic zinc on steelwork forms a durable barrier affording considerable protection under normal conditions. The second reason arises from the fact that zinc is considerably more electronegative than iron, and when the two metals are in contact in an electrolyte, zinc tends to dissolve, leaving the iron unattacked.

Assignments:

1.Name two reasons why zinc coatings are one of the best methods for the protection of steelwork against corrosion.

2.Render the text.

2.4. Lead

Lead is naturally present, in small amounts, in soil, rocks, surface waters, and the atmosphere. Due to its unique properties it has been an element widely useful to human.

When freshly cast, lead has a bright silvery appearance but, upon exposure to air, the surface soon becomes grey or greyish-white due to the formation of oxide, basic carbonate or basic sulphate films which in most atmospheres protect the surface from further corrosion.

Its softness and low melting point make lead very easy to handle and fashion. Its high resistance to corrosion makes it ideal for weatherproofing buildings and for equipment used in the manufacture of acids. Lead’s high

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density makes it particularly appropriate as a shield against radiation in the nuclear industry and in hospitals. For the same reason lead is also good at stopping sound waves and so is used to reduce noise from machinery in factories and from engine rooms on ships. However, the most important use of lead today is in the lead-acid battery which provides power in numerous situations. The most familiar use of the lead-acid battery is to start our cars and other vehicles, but they are also used to power electric vehicles and to provide emergency power when the electricity fails.

The qualities of lead are unrivalled and it is irreplaceable in many of its uses. Consequently this versatile metal will be needed as much in the future as it has been in the past.

Lead metal is described as being either primary or secondary. Primary lead is produced directly from mined lead ore. Secondary lead is produced from scrap lead products which have been recycled.

Around 3 million tons of lead are mined in the world each year. Lead is found all over the world but the largest mining countries are Australia, China and the United States, which between them account for more than 50 % of primary production.

The most common lead ore is galena or lead sulphide. Other elements frequently present include zinc and silver. In fact lead ores constitute the main sources of silver, contributing substantially towards the world’s total output.

Lead is obtained from galena by a process called smelting. This involves roasting the ore to remove the sulphur and to obtain lead oxide which is then reacted with coke in a furnace. The resulting lead bullion contains many impurities such as silver and gold (hence the name bullion) as well as antimony, arsenic, copper, tin and zinc. These impurities are then removed by various refining steps to obtain pure lead.

A further 3 million tons of lead are produced from secondary sources each year, by recycling scrap lead products such as sheet, pipe and batteries. In fact, in the western world today more lead is produced by recycling than by mining.

At least three-quarters of all lead used goes into products which are suitable for recycling. This is why lead has the highest recycling rate of all the common non-ferrous metals. The use of secondary metal makes some important contributions to the environment. Firstly, the recovery of lead from scrap requires far less energy than smelting from ore. Secondly, recycling keeps unwanted products out of the waste stream and puts them to good use. Thirdly, recycling conserves our natural resources for the benefit of future generations.

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Exercise 1. Look through two columns of the words. Find the syno-

Exercise 2. Match the definitions with the following words:

Exercise 4. Are these statements true or false?

1.Lead is naturally present, in large amounts, in soil, rocks, surface waters, and the atmosphere.

2.When freshly cast, lead has a greyish-white appearance.

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3.Lead has low melting point and resistance to corrosion.

4.Lead’s high density makes it particularly appropriate as a shield against radiation.

5.Primary lead is produced directly from mined lead ore.

6.About 3 million tons of lead are mined in the world each month.

7.The most common lead ore is galena.

8.A further 3 million tons of lead are produced from secondary sources each year.

9.Lead has the lowest recycling rate of all the common non-ferrous metals.

Exercise 5. Answer the questions:

1.Where is lead naturally present?

2.What are the general properties of lead?

3.What makes lead very easy to handle and fashion?

4.Where is lead used?

5.What is the most important use of lead today?

6.How is lead metal described?

7.What are the largest mining countries in the world?

8.What is the most common lead ore?

9.How is lead obtained from galena?

10.Why does lead have the highest recycling rate?

11.Why does the use of secondary metal make important contribution to the environment?

Do you know that:

In the British Museum can be seen the earliest known example of metallic lead in the form of a figure recovered from the Temple of Osiris at Abydus in Upper Egypt. This is considered to date back to almost 4000 B.C., although pottery with lead-bearing glazes is said to have appeared almost 1000 years earlier.

Historical references to lead began to appear about 1500 B.C. and many can be found in the Bible. From about 500 B.C., historical references to lead are more numerous, particularly in the writings of the Greek and Roman authors. The well known book by Healy gives a most comprehensive account of mining and metallurgy through Greek and Roman times. It contains a detailed bibliography of the sources of information, together with maps of Europe and the British Isles showing the known early mining localities.

Sheet lead, made by casting on a flat stone base, was used by both the Greeks and Romans for many practical purposes including roofing, the lining of ducts and fountains and the protective sheathing of the wooden hulls of ships.

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It was the Romans who were mainly responsible for the development and expansion of the practical uses of lead and the word “plumbing” is derived from the Latin word for lead, “plumbum”. As early as 300 B.C., Rome had its first aqueduct, bringing water from seven miles away into the city, and this was later extended by further aqueducts and a distribution system of pipes made of lead. These practical applications increased the demand for the metal and led the Romans to seek control of more sources of supply.

The Roman conquest of Europe and later Britain led to the development of mining and smelting activities in those countries and many pigs (ingots) of lead dating from Roman times can be seen in various museums. Some of these pigs are marked “ex argent”, indicating that the lead has been desilverized. The historian Pliny gives a fairly detailed account of the cupellation process.

Following the decline of Roman civilization, there was little further development of mining and smelting for 1000 years or more, although the use of lead continued in Europe and Britain.

Assignments:

1.Explain the phrase “Eventually the Romans suffered some leadpoisoning”.

2.Render the text.

2.5. Brass.

The addition of zinc to copper to form brass is the oldest and one of the most important applications of zinc. The art of producing bronze by alloying copper with tin was developed relatively early and was one of primitive man’s greatest technological advances, but, due to the difficulties inherent in the metallurgy of zinc, brasses do not seem to have been produced until the first or second century B.C., when the cementation process was practised in India and China, and also in Europe by the Romans. A mixture of zinc oxide and charcoal was placed in a crucible and covered by a layer of pieces of copper. The crucible was heated to 1000 degrees, when the zinc oxide was reduced and formed zinc vapour, which dissolved in and was retained by the copper. As the zinc content of the copper rose to approximately 30 per cent, the alloy began to melt and ran down to the bottom of the crucible, and at the end of the reaction was cast into moulds – usually made of stone slabs – and later hammered into the shapes required. The process did not involve the separation of zinc as metal.

The method was the main source of brass production for many centuries. It was not capable of producing alloy containing more than 30 per cent zinc, and, due to losses which must have been difficult to avoid, considerable skill must have been required to reach this figure.

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