Міністерство освіти і науки, молоді та спорту України

Національний технічний університет України

«Київський політехнічний інститут»

English for specific purposes environmental issues

In metal production

ДИДАКТИЧНІ МАТЕРІАЛИ

для практичних занять

для студентів 5 курсу інженерно-фізичного факультету

2012

Англійська мова для професійно-орієнтованого спілкування: Дидактичні матеріали для практичних занять для студентів 5 курсу інженерно-фізичного ф-ту / Уклад. О. М. Леонова, О.А. Гришина, О.С.Дубініна, Н.С. Нікітіна - К.: НТУУ «КПІ», 2012.- 92 с.

Навчальне видання

АНГЛІЙСЬКА МОВА ПРОФЕСІЙНОГО СПРЯМУВАННЯ

ДИДАКТИЧНІ МАТЕРІАЛИ

для практичних занять

для студентів 5 курсу інженерно-фізичного факультету

Укладачі:	О. М. Леонова, О.А. Гришина, О.С.Дубініна, Н.С. Нікітіна
Відповідальний редактор:	Корсун Ганна Олексіївна

C O N T E N T S

Preface	………………………………………………………..…….…….			4
Unit 1	By-Product Management Issues………………………………….			8
Unit 2	What Is Cleaner Production & What Are Its Benefits?.............			12
Unit 3	Environmental Issues……………………………………………			15
Unit 4	Technology of Manufacturing Alloys from Industrial Wastes….			17
Unit 5	International Environmental Bureau……………………….…..			20
Unit 6	Waste Sources and Pollution Prevention Opportunities in Aluminium Production………………………………………….			23
Unit 7	Pollution Sources and Prevention in Zinc Production………….			27
Unit 8	Pollution Prevention in Iron and Steel Manufacturing Industry….			34
Unit 9	A New Process for Recycling Steelplant Wastes………………...			38
Unit 10	Ecology at Zaporizhstal JSC……………………………………...			46
Unit 11	Noise Campaign in the Foundry Industry………………………...			49
Unit 12	Green Technologies………………………………………………			54
Appendix I			…………………………........……………………...............	62
Appendix II			…………………………........……………………...............	65
Appendix III			…………………………........……………………...............	67
Appendix IV			…………………………........……………………...............	72
References		…………………………........……………………..............		92

UNIT 1

BY-PRODUCT MANAGEMENT ISSUES FOR THE QUEENSLAND FOUNDRY INDUSTRY

Although the foundry industry is traditionally been viewed as dirty and hazardous, modern foundry processes are relatively clean and impacts are generally related to environmental nuisance issues such as noise and odour rather than impacts that are hazardous to human health and the environment.

Most foundries have made considerable effort to minimise these impacts and foundries located in build up areas, have developed sophisticated noise and odour management systems and regularly monitor emissions from the site.

The most significant waste management issues for the foundry industry is the generation of large quantities of spent sand and other solid by-products such as baghouse dust and slag. Table 1 provides quantities of sand and other solid wastes generated by the foundry industry in Queensland. Historically, many foundries disposed of these materials on site, however this practice has given way to landfill disposal. As the costs of landfill disposal continue to rise, alternatives to disposal are being pursued.

Table 1:	Quantities of sand and other solid wastes generated by Queensland foundries
Waste		Tonnes/year
Spent green sand		11,322
Spent phenolic bonded sand		9,799
Spent silicate bonded sand		17,688
Spent furan-bonded sand		3,496
Resin coated sand		3,913
Spent silicate bonded zircon		8
Core sand		1,140
Baghouse dust (FFDC Dust)		3,023
Shot-blast dust		616
Furnace slag		2,465
Dross		127
Induction furnace lining		114
standard firebrick		8
ladle lining		807
Furnace consumables - thermocouples etc.		48
Sand reclamation dust		132
Shot blast sand		72
Clay graphite used pots (borden)		1
General waste which cannot be recycled		1
Approximate Total		54,780

Note: This table does not include the Maryborough and Bundaberg foundries. A survey conducted in 1995 by the MITA (now the Australian Industries Group) estimated the State’s waste foundry sands (including these foundries) to be approximately 75,690 tonnes per year. The economic downturn has reduced the volume of waste generated by the industry in recent times. Source: (EPA, 1999)

These waste and by-product streams are relatively benign, particularly those generated from ferrous foundries. Most chemical additives used for sand binding are inert or of organic origin which biodegrade relatively quickly (EPA,1999). For ferrous foundries, waste sand typically passes toxic characteristic leaching procedure (TCLP) tests and can therefore be sent to non-secured landfill. Non-ferrous foundry sands are usually sent to secured landfill due to the presence of heavy metals. Baghouse dust from ferrous foundries is also sent to secured landfill, due to the fact that the dust is extremely light so is a potential occupational health and safety issue.

In total, about 46000 tonnes of spent foundry sand is generated per year in Queensland, 85% of which is disposed to landfill. Around 4,920 tonnes is being used as night cover at landfill sites and a further 2,280 tonnes is being used as a composting material. Therefore around 15% of the total spent sand is currently being used for some form of beneficial reuse.

In response to the increasing costs of landfill disposal, beneficial reuse of foundry byproducts has received considerable attention by the industry in recent years, culminating in the development by the Queensland EPA of an Environmental Guideline, Beneficial re-use of ferrous foundry by-products. Five of the major ferrous foundries in Queensland hope to achieve 100% beneficial reuse for their major waste streams, (i.e. sand, baghouse dust and slag) within the next five years. If these companies achieve their stated goals, the volume of material diverted from landfill could be realistically increased from the current level of 15% to around 70% over the next five years. This would reduce the volume of material going to landfill by 25,000 tonnes per year. Beneficial reuse options are generally more limited for non-ferrous foundries, small foundries, and foundries that are located a long way from potential users of the byproducts.

While beneficial reuse will play an important role in by-product management, greater potential value can be gained from Cleaner Production. Beneficial reuse is an ‘end-of-pipe’ strategy that reduced the cost of waste once it has been generated. Cleaner Production stops the waste occurring in the first place so can potentially reduce the cost of purchasing materials as well as reducing the cost of unnecessary processing, handling and disposal costs.

In general, the outlook for Cleaner Production in Queensland’s foundry industry is quite promising with many of the ideas presented in this manual already being undertaken. Based on a recent survey of Queensand’s major foundries, companies have actively sought to minimise waste and maximise resource efficiency in a number of areas throughout the foundry. Some of the most interesting examples include:

• Beneficial reuse of industry byproducts, particularly sand, baghouse dust and shotblast;

• On-site and off-site sand reclamation and reuse;

• Energy efficiency programs (e. g. covering ladles, energy management and production scheduling, ensuring equipment is turned off when not in use, capturing waste heat from the furnaces and heat treatment processes);

• Increasing on-site recovery and reuse of metals including shotblast, machining fines and baghouse dust metals;

• Better segregation of shotblast from sand to increase reclamation;

• Conversion of baghouse dust to slag to reduce disposal costs or increase beneficial reuse options;

• Regenerating machine cutting oils;

• Investigation of new resin systems;

• Changing energy sources (e.g. grid power to bagasse, propane to natural gas, diesel to electricity); and

• Improving layout and housekeeping practices.

Reclaiming sand for reuse within the foundry process is seen as an important means of reducing the amount of sand disposed to landfill. Many of the larger foundries currently undertake manual sand reclamation. For foundries that produce large, iron castings sand recovery rates for manual reclamation can be as high as 90-96%, however for most operations in Queensland, recovery rates for those foundries undertaking reclamation is typically around 70-80%.

A number of Queensland companies are in the process of installing manual sand reclamation systems or optimising the systems to increase recovery rates. Thermal reclamation has not been widely adopted in Queensland due to the high cost of the systems and the relatively small volumes of sand generated in the state. One Queensland foundry, using a shell casting process, has recently commenced thermal sand reclamation to recover 100% of its waste sand. Many of the conventional sand casting operations have investigated thermal reclamation and may invest in these systems in the future.

Figure 1: Sand Flows in the Queensland Foundry Industry

	The Queensland Foundry Industry
N ew Sand Purchased 48,700 tpa		S pent Sand 46,400 tpa
	Sand Lost (< 5% baghouse dust & general loss) 2,300 tpa	L andfill 85% B eneficial Reuse 15%

As depicted in Figure 1, the average rate of internal sand reclamation for the Queensland foundry industry as a whole is currently 36%. Based on stated plans by several Queensland foundries, the industry average could potentially increase to 50% within the next two years.

Moving beyond 50% recovery will be relatively difficult. A further 5% may be gained if companies improve the efficiency of the current systems. Further gains will probably only be possible through the greater use of thermal reclamation, by improving moulding techniques to reduce the sand input, by changing to different casting processes or by identifying cost effective methods for sand reclamation at small foundries.

While significant work has already been undertake, most Queensland foundries recognise that there are many opportunities for continuous improvement in terms of by-product minimisation and for improving resource efficiency. Key areas identified by the sector include improved sand reclamation, metal yields, energy efficiency and the beneficial reuse of byproducts. All of these opportunities are discussed in further detail in this report.

UNIT 2

WHAT IS CLEANER PRODUCTION & WHAT ARE ITS BENEFITS?

Cleaner Production focuses on eliminating waste and inefficiency at their source, rather than finding ‘end-of-pipe’ solutions once the wastes have been generated. It involves rethinking conventional methods to achieve ‘smarter’ production processes and products to achieve sustainable production.

In adopting the Cleaner Production approach, try to consider how wastes can be avoided in the first place rather than focusing on how to manage or treat them once they have been generated.

Waste avoidance and reduction should be considered as the first options. Once all avoidance and reduction options have been eliminated, then options for on-site reuse and recycling can be considered. Only as a last resort should treatment and disposal options be considered. This approach is depicted in the Cleaner Production Hierarchy shown in Figure 2.

Cleaner Production has been the major environmental initiative for industries in the 1990’s. Thousands of manufacturing companies, including foundries have taken up Cleaner Production approaches to manufacturing.

Figure 2: The Cleaner Production Hierarchy

	Eliminate Reduce Reuse Recycle Treat and Dispose	FOCUS STRATEGY	Waste prevention Waste management Control and disposal
	All media Air, Water, Solid	Raw Materials Energy Use	Work Procedures	Impact of Products

Saving money

Cleaner Production can save money; money which would have otherwise been spent on wasted resources, waste treatment, disposal and compliance costs.

Cleaner Production strategies typically cost less than treatment and disposal (so called ‘end-of-pipe’) technologies. Complying with the emission limits established by government through on-site treatment can be a significant cost; may require specialist knowledge and attention, and generally provide no profit for the organisation.

Many strategies, such as general housekeeping and process improvements can be implemented at low cost and can have immediate benefits, up to 30% in some cases. Substantial process modifications or technology changes will require capital investment, however numerous case studies demonstrate that pay-back periods can be as little as months to 2 years.

Preventing pollution

Pollution prevention by reducing energy, water and resource consumption and minimising waste is at the core of Cleaner Production. With the emphasis on reducing waste at the source rather than controlling pollution after it has been generated with ‘end-of-the-pipe’ solutions, many pollution problems can be eliminated.

Complying with environmental legislation

Working toward Cleaner Production will greatly assist in complying with stricter environmental legislation, bringing the benefits of reduced liability, reduced regulation, reduced monitoring costs, potentially reduced licensing charges and better control over your business. Environmental regulations and standards are becoming tighter and more comprehensive and this trend is expected to continue in the future. The Environmental Protection (Waste Management) Policy embraces the waste management hierarchy and in some cases requires businesses to prepare a Cleaner Production Plan. Table 3 contains the type of information that must be included in Cleaner Production Plans.

Table 3: Contents of a Cleaner Production Plan
A Cleaner Production Plan must contain details of:	A Cleaner Production Plan may need to address other issues such as:
Current waste management practices; Material, energy and resource inputs; Material, waste and energy outputs; Impacts of the production process on environmental values; Opportunities and actions to be taken to avoid and reduce waste (including toxicity, energy and water); Opportunities and actions to be taken to recycle wastes; Recommendations of any life cycle assessment conducted; Targets and goals; Program of action and timeframes; Any certified or approved quality assurance or environmental management system or standard; Monitoring and reporting program.	input substitution - replacing an input with a non-hazardous or less hazardous substance; and/or product reformulation - substituting an alternative end product which is non-hazardous or less hazardous upon use, release or disposal; and/or production process modification - upgrading or replacing existing production process equipment and methods with other equipment and methods, and/or improved operation and maintenance of production process equipment and methods - modifying or adding to existing equipment or methods; and/or closed-loop recycling - recycling or extended use of substances which become an integral part of the production process.

UNIT 3

ENVIRONMENTAL ISSUES

Queensland Foundry Industry. Cupola, reverberatory and electric arc furnaces may emit particulate matter, carbon monoxide, hydrocarbons, sulfur dioxide, nitrogen oxides, small quantities of chloride and fluoride compounds, and metallic fumes from the condensation of volatilised metal and metal oxides. Induction furnaces and crucible furnaces emit relatively small amounts of particulate matter, hydrocarbons and carbon monoxide (USEPA (1998) and Environment Canada (1997)).

Table 3: Emission Factors for Uncontrolled Furnaces
Process	Grey iron foundries (kg/tonne)	Steel foundries (kg/tonne)
Cupola	8.5
Electric arc	5	6.5
Electric induction	0.75	0.05
Reverberatory	1
Note: Emissions are expressed as weight of pollutant per weight of metal melted. Source: Environment Canada (1997)

As shown in Table 3, cupola furnaces generate the largest quantity of emissions per tonne of charge. This is largely due the fact that the charge material typically includes greater levels of contamination, but is also due to the use of coke. Cokeless cupola furnaces achieve significantly lower emission rates. Emissions from electric melting furnaces are relatively low. They typically include gases and dust, which originate from contamination in the charge such as oil, dirt and rust. Most emissions occur during a short period after charging. The emissions also include fine metal and oxide particles. Generally, higherfrequency induction furnaces will generate less of this material because lower stirring rates result in less contact between the metal and air (UNEP, 1997). Electric induction furnaces achieve the lowest emissions, particularly for steel foundries where emissions can be virtually eliminated.

Slag is also generated during metal melting operations. Hazardous slag can be generated if the charge materials contain enough toxic metals, such as lead and chromium, or if calcium carbide is used in the metal to remove sulfur compounds (USEPA, 1998).

These emission factors, for fugitive particulate matter from grey iron foundries using an electric arc furnace, are broken down by process in Table 4.

Table 4: Emission Factors for Fugitive Particulates from Grey Iron Foundries (Electric Arc Furnace)
Process	Emissions (kg/tonne)	Emitted to work environment (kg/tonne)	Emitted to atmosphere (kg/tonne)
Scrap and charge handling, heating	0.3	0.25	0.1
Magnesium treatment	2.5	2.5	0.5
Sand handling and preparation	20	13	1.5
Core making, baking	0.6	0.6	0.6
Pouring	2.5	2.5	1
Cooling	5	4.5	0.5
Shakeout	16	6.5	0.5
Cleaning, finishing	8.5	0.15	0.05
Note: Emissions are expressed as weight of pollutant per weight of metal melted. Source: Environment Canada (1997)

UNIT 4

INTERNATIONAL ENVIRONMENTAL BUREAU FOR THE NON-FERROUS METAL INDUSTRIES

The British Non-Ferrous Metals Research Association (BNFMRA) proposes to set up an Environmental Bureau to assist the non-ferrous metals industry to deploy its resources to best advantage in combating pollution and to provide authoritative data on questions of the environment. The suggestion has arisen from the greatly increased concern about environmental matters that has been generated over the past year or so and the need for all industrial concerns to keep up to date in a rapidly changing situation. The BNFMRA, which already has strong international connections, is well fitted to provide a nucleus for such a Bureau having been involved with environmental issues for over ten years.

The industry is not a major cause of pollution when viewed on a world scale, but questions have been raised about some operations, particularly those of smelters, where the scale is necessarily large and the environmental problems correspondingly magnified. There is a consciousness in the industry of a continuing need to improve the environment, and also of a need for more information about the ecological influences of emissions and effluents.

While pollution is in the main a local problem, affecting areas of high density population most critically, it is considered that in the longer term all sections of the non-ferrous metals industry throughout the world can benefit from co-operation over environmental issues, and the Bureau is being established on an international basis. It is hoped that it will attract a world-wide membership and quickly become recognized as a world authority.

Essentially the Bureau will act as an information and co-ordinating centre dealing with all environmental matters associated with non-ferrous metals extraction, refining and fabrication. It will cover atmospheric emissions, liquid effluents, solid wastes and the physical problems of noise, both within and outside factories. In addition to collating and reviewing published information, the Bureau will act as a channel for the exchange of information on the performance of plant and processes for combating pollution.

Working Parties will be set up to pursue specific investigations, and experienced chemical and metallurgical engineers will be available for practical work and detailed consultations. The Bureau will be in a position to supply reliable data to the industry in its negotiations with legislating authorities. The intention is to open membership of the Bureau to firms in the non-ferrous metals industry in the UK and overseas at a low basic subscription to encourage a wide support.

Task 1.

Pay attention to the pronunciation of the following words and word combinations:

environmental Bureau, suggestion, authoritative, environmental issues, liquid effluents, emissions and effluents, combating pollution.

Task 2.

Translate the following words and word combinations into English:

промисловість кольорових металів, найкраща перевага, тісні міжнародні зв’язки, причина забруднення, світовий масштаб, проблеми забруднення навколишнього середовища, вихлопні викиди та рідкі промислові відходи, висока густина населення, співробітництво з питань навколишнього середовища, інформаційний центр-координатор, добування кольорових металів, обмін інформацією, захист навколишнього середовища, заснувати партію, досвідчені інженери металурги, законодавчі органи.

Task 3.	Fill in the table with the missing information and be prepared for speaking on the topic “International Environmental Bureau for the Non-ferrous Metal Industries”.
Who proposes to set up an Environmental Bureau? __________________________________________________________________________
How many years has Environmental Bureau been involved in environmental issues? __________________
Functions of Environmental Bureau’s:

UNIT 5

TECHNOLOGY OF MANUFACTURING ALLOYS FROM INDUSTRIAL WASTES

During the last years the Physic-Technological Institute of Metals and Alloys of National Academy of Sciences of Ukraine has intensively been working in the field of manufacturing metals and alloys from different industrial wastes by a method of reducing oxides of metals in iron-carbon melt.

Among numerous wastes of the economic activity a special place is occupied by high toxic wastes containing in particular such metals as Cd, V, Co, Pb, Hg, Mo and others. In this connection the problem of utilizing the referred to above wastes in particular electroplating sludge for industrialized countries, including, Ukraine, is one of the most important.

The fulfilled analysis of the compositions of electroplating sludge and worn-out catalysts from some Ukrainian enterprises has shown that all wastes by their chemical composition are close to polymetallic ores, and therefore, for their processing metallurgical technologies can be used.

The investigation of peculiarities of the technological process of remelting different wastes and melting alloys can be conducted in a plasma furnace. As a reductant in this case carbon in the form of electrode breakage is used.

It has been revealed that during melting at the arc current of 200-600 A up to 70 % of volatile matters is withdrawn from sludge and up to 30 % of a solid concentrate, consisting from metal and sludge, is formed.

The yield of metallic base and its chemical composition obtained show that at remelting electroplating sludge a high yield of metallic base with a high content of Cr and Ni is reached.

In future alloys melted of sludge have been used for melting alloy cast irons and steels. Chemical composition of manufactured melted cast irons and steels is close to the composition of alloys, regulated by acting normative documents.

More effective process is the use of electroplating sludge in charge during melting, at which an intermediate metallurgical process stage is excluded. In this case the withdrawal of volatile matters and reduction of metal oxides is carried out in iron-carbon melt during melting.

It should be noted that the basis metal Cr and Ni are reduced in iron-carbon melt adequately and the degree of their reduction amounts to 80-90 %.

The implemented investigations gave an opportunity to develop scientific fundamentals for elaborating a technology of manufacturing alloys with the use of industrial wastes.

Thus, metallurgical technologies of processing industrial wastes enable to accomplish the following tasks:

• to withdraw volatile matters from different organic and inorganic compounds;

• to extract metallic base from sludge, containing deficit alloying elements;

• to eliminate the influence of toxic wastes on environment in places of their formation.

Task 1.

Find in the text English equivalents to the following words:

виробництво металів, промислові відходи, залізо-карбоновий сплав, зношені каталізатори, поліметалічні руди, обробка, особливості технологічного процесу, відновлювач, зношений, летучі речовини, проведені дослідження, розробити наукові основи, металічна основа, органічні сполуки, переробка (утилізація), нанесення гальванічного покриття.

Task 2.

Give Ukrainian equivalents to the following words and word combinations:

intensively, field of manufacturing, industrial wastes, method of reducing, iron-carbon melt, numerous, to occupy, to contain, the problem of utilizing, the industrialized countries, to include, enterprise, chemical composition, polymetallic ores, processing, investigation, peculiarity, remelting, alloys, plasma furnace, a reductant, arc, volatile matters, sludge, yield, to obtain, cast irons and steels, charge, to exclude, reduction of metal oxides, to enable, to accomplish, to eliminate, influence, environment.

Task 3.

Answer the following questions:

Name the field the Physic-Technological Institute of Metals and Alloys of National Academy of Sciences of Ukraine has intensively been working in.

What wastes are mentioned in the text?

What metals do high toxic wastes contain?

What method did the scientists use manufacturing metals and alloys from different industrial wastes?

Can be metallurgical technologies used for processing electroplating sludge and worn out catalysts? Why?

Where can be the investigation of peculiarities of the technological process of remelting different wastes and melting alloys conducted?

What constituents of a solid concentrate were withdrawn from a sludge?

What tasks should be completed in metallurgical technologies of processing industrial wastes?

Can the influence of toxic wastes on environment be completely eliminated?

Task 4.

Complete the following sentences with the missing words. Translate the sentences.

electrode breakage, metal and sludge

1. As a reductant in this case carbon in the form of _____________ is used.

2. During melting at the arc current of 200-600 A up to 70 % of volatile matters is withdrawn from sludge and up to 30 % of a solid concentrate, consisting from _____________ is formed.

Task 5.

Copy out the key words from the text and make up your own sentences with them.

UNIT 6

WASTE SOURCES AND POLLUTION PREVENTION OPPORTUNITIES IN ALUMINIUM PRODUCTION

Air emissions come from a number of sources. The grinding of the bauxite, calcinating the aluminium oxide, and handling materials produce particulates. Air emissions equipment is used extensively to capture these particulates. The particulates may be metal rich. If the metallic content is sufficient, the emissions control dust can be re-melted to capture any remaining metals or it may be otherwise reused or sold for its metallic content. If the dust is not sufficiently metal rich, it usually landfilled.

Another source of air emissions from primary aluminium production processes occurs during the reduction of aluminium oxide to aluminium metal. Hydrogen fluoride gases and particulates, fluorides, alumina, carbon monoxide, sulfur dioxide and volatile organics are produced. Electrolytic baths often use anode pastes in the cell. The paste must be continually fed into the cell through a steel sheet with an opening. This continual feed allows the gas to escape.

One method for reducing gas emissions is the use of pre-baked anodes. Pre-baked anodes must be manufactured in an on-site plant. The pre-baked anodes allow the electrolytic bath to be sealed, allowing gas to be captured. The anodes are then replaced every 14-20 days, containing the gasses for collection. Anode baking furnaces produce fluorides, vaporized organics and sulfur dioxide emissions. The emissions are often controlled using wet scrubbers.

Liquid waste is not a great concern in aluminium processing. Wastewater is produced during clarification and precipitation; however, much of the water is directly reused. Solid phase wastes include bauxite refining waste, called red mud, and reduction waste from spent pot liners. Red mud contains iron, aluminium, silica, calcium and sodium, depending on the ore used. Usually red mud is managed on site and is not hazardous.

Air emissions and solid-phase wastes are the primary concerns in the secondary aluminium processing industry. Air emissions depend largely on the quality of scrap used. Emissions can come from smelting, refining, and the furnace effluent gases. Gases can include combustion products, hydrogen chloride and metal chlorides, aluminium oxide metals and metal compounds. To reduce emissions regardless of the type of scrap used, aluminium fluoride can be substituted for chlorine to remove impurities from the molten metal. All systems are usually connected to emissions control equipment, typically a baghouse for collecting fluorine and other gases.

Solid-phase waste from secondary aluminium production is slag formed during smelting. The slag contains chlorides, fluxes and magnesium. The metal lies may be separated and reused or sold.

Liquid wastes include water that is added to the slag to help separate the different metals. The waste water may be contaminated with salt and fluxes, but can often be recovered and reused.

Task 1.

Translate into English the following words and word combinations:

викиди у повітря, подрібнення бокситу, відпал (кальцинування), обробка (транспортування), обладнання для контролю небезпечних викидів у повітря, вловлювати (макро)частинки, закопувати відходи, розкислення, летючі органічні речовини, електролізер, на місці, газоочисник (мокрий пиловловник), рідкі відходи, очищення (ректифікація, освітлення), осадження, стічні води, червоний шлам, футеровка (покриття), викидні гази, продукти горіння, металеві сполуки, заміщувати, пиловловник з рукавом зі тканини, забруднювати, вторинне виробництво алюмінію, видалити домішки, очистка і плавлення, відокремлювати метал.

Task 2.

Translate into Ukrainian the following words and word combinations:

primary aluminium production, reduction of aluminium oxide, particulates, alumina, carbon volatile, electrolytic bath, to be continually fed, a steel sheet with an opening, to escape, pre-baked anode, on-site, to seal, to capture, collection, emissions, wet scrubber, to be a great concern, wastewater, clarification, precipitation, to reuse, wastes, red mud, liner, ore, hazardous, to depend on, scrap, smelting, refining, effluent gases, combustion products, compound, to reduce, to remove impurities, molten metal, emissions control equipment, baghouse, slag, to separate, to be contaminated, to recover.

Task 3.

Check if you remember the meanings of the following words:

bauxite, hydrogen fluoride, fluorides, alumina, carbon monoxide, sulfur dioxide, aluminium fluoride, silica, calcium, sodium, hydrogen chloride, chlorides, metal compounds, iron, aluminium, magnesium, flux, oxide, salt, vaporized organics.

Task 4.

Make a short report on one of the following topics:

1) Pollution prevention opportunities in aluminium production

2) Wastes in aluminium production

Task 5. Fill in the table with the necessary information using the text:

	Sources of waste	Ways of reduction or prevention	Additional information
Air emissions	primary aluminium production - grinding of the bauxite - _____________________ - handling materials	- use of air emissions equipment	- particulates
		- can be re-melted, reused or sold	- _______________________
		- ______________________	- not sufficiently metal rich
	- _______________________	- the use of pre-baked anodes (allow gases to be captured)	- hydrogen fluoride gases and particulates, fluorides, alumina, ____________, sulfur dioxide and _________ organics
	- anode baking furnaces	- ___________________	- ___________________ ____________________
	secondary aluminium processing - smelting - ____________________ - furnace effluent gases	- emissions control equipment ___________ for collecting fluorine and other gases - fluoride can be substituted for chlorine to __________ ___________ from the molten metal	- air emissions depend largely on ____________ used. - gases can include combustion products, ____________________ ________________________________________
Liquid waste	primary aluminium production - ____________________ - precipitation	- ___________________ ____________________	- wastewater is not a great concern
	secondary aluminium processing	- can often be ____________ and reused	- water (added to help to separate the different metals) is contaminated with _______________________
Solid waste	primary aluminium production	is managed ________ and is not hazardous	- ___________(contains iron, aluminium, silica, calcium, sodium) and ____________________ ____________________
	secondary aluminium processing	- metal may _____________ and reused or sold	- slag formed during ___________ (contains chlorides, fluxes, magnesium)

UNIT 7

POLLUTION SOURCES AND PREVENTION IN ZINC PRODUCTION

Primary zinc production produces air emissions, process wastes and solid-phase wastes emissions come primarily from the zinc roasting process and consist primarily of sulfur dioxide emissions. Most emissions are recovered on site in sulfuric acid production plants, where sulfuric acid is produced.

Zinc roasters also produce particulate emissions. Particulate air emissions from primary zinc production often contain cadmium, lead and other compounds, depending on inputs. The slurry formed from the emissions control equipment is K066 hazardous waste.

The electrowinning process produces waste heat. Rather than letting the hot gas escape into the environment, some is recovered and sent to cooling towers where the steam is collected for reuse. Wastewater is produced from leaching, purification and electrowinning. The water is usually treated and discharged. Reuse opportunities may be available.

Solid wastes include acid plant slurries, sludge from electrolytic cells and copper cakes, a by-product of zinc production, from the purification cells. Much of the waste is considered RCRA hazardous waste. Anode slime from electrolytic cells consists of impurities not captured prior to the electrowinning process. The composition usually makes the slime a RCRA hazardous waste. Copper cakes are captured and sold to copper processing plants.

Secondary zinc processing produces air emissions and solid waste emissions. Air emissions come from sweating and melting. The emissions include particulates, zinc fumes, volatile metals, flux fumes and smoke, rubber, plastics and zinc scrap. Incomplete combustion products are also emitted, but are eliminated when passed through an after burner. Particulates are collected in emissions control equipment such as baghouses. The particulates are often refined for the metals.

In distillation and oxidation processes, zinc oxides in the form of dust are produced. The oxides are collected in baghouse emissions control systems. Air emissions are also common from the pyrometallurgical processes. If simple re-melting of the zinc is required, the emissions are not high. However, if the zinc requires reduction or other refinement, emissions are likely. The lower the quality of zinc scrap, the more air emission produced in the process. Air emissions are usually collected in ventilation systems. The emissions control dust is usually sold as fertilizer or animal feed.

Solid waste is present in the form of slag. The slag from secondary zinc production usually contains copper, aluminium, iron and lead. Slag is generated during pyrometallurgical processes and may be hazardous.