冶金专业英语(全)

2021年3月3日发(作者：flat什么意思)

有

色

冶

金

专

业

英

语

（适用于冶金工程专业）

2009

年

9

月

1

Lesson 3

Ore

Dressing

Ore dressing

选矿

Concentrate

v.

富积，浓缩，集聚

n.

精矿，浓缩物

Concentration

n.

集中，浓缩，浓度

Acid concentration

酸浓度

Bulk

n.

正体，主体，团块

Gangue

n.

脉石，尾矿，矿脉中的夹杂物

Tailing

n.

尾矿

Severance

n.

分离，隔离，碎散

Beneficiation

n.

分选

Comminution

n.

粉碎

Run-of-mine

n.

原矿

Middling

n.

中矿

Liberation

n.

解离

Crush

n. v.

粉碎，碾碎，挤压

Grind

n. v.

研磨，磨细

Screen

n. v.

筛，筛分

Jigging

n.

跳选，跳汰选

Hand picking

手选

Luster

n.

光泽，光亮

v.

闪光，发光

Specific gravity

比重

Magnetic permeability

磁导率

Inductive charging

感应电荷

Electrostatic separation

静电分离

Fracture

n.

断口，裂缝

Automatic sorting of radioactive natures

放射性自动选矿

Magnitude n.

大小，尺寸，量级，强度，等级

Magnetic separation

磁选

Magnetic field

磁场

Gravity concentration

重力选矿

Medium

n.

介质，媒介，中间物，培养基

Dilate

v.

（使）膨胀，扩张，扩大

Dilated bed

松散床层

Dilation

n.

膨胀系数，传播，伸缩，蔓延

Lip

n.

凸出部分，唇部

Diverse

adj.

不同的，互异的，各种各样的

Table

n.

摇床，淘汰盘

Tabling

摇床选，淘汰选

Motion

n.

运动，输送，行程，机械装置，运动机构

Sink-float separation

重介质分选

Suspension

n.

悬浮物，悬浮液

Cone

n.

圆锥体，锥形漏斗，圆锥破碎机

Stir

n. v.

移动，摇动，搅拌

Stirrer

n.

搅拌器，搅拌机

Rotary

adj.

旋转的，回转的，转动的

Circumference

n.

圆周，周边

Rotating motion

旋转装置，旋转设备

Floatation

n.

浮选

Pulp

n.

矿浆，浆料

v.

制浆，浆化

Sluice

n.

槽，排水道，水槽

Froth floatation

泡沫浮选

Hematite

n.

赤铁矿

Pyrolusite

n.

软锰矿

Diamond

n.

金刚石

Graphite

n.

石墨

2

Ore dressing concerns with the technology of treatment of ores to concentrate their valuable constituents (minerals) into

products (concentrate) of smaller bulk, and simultaneously to collect the worthless material (gangue) into discardable waste

(tailing). The fundamental operations of ore-dressing processes are the breaking apart of the associated constituents of the

ore

by

mechanical

means

(severance)

and

the

separation

of

the

severed

components

(beneficiation)

into

concentrate

and

tailing, using mechanical or physical methods which do not effect substantial chemical changes.

1

Severance

. Comminution is a single, or multistage processes whereby ore is reduced from run-of-mine size to that size

needed

by

the

beneficiation

processes.

The

process

is

intended

to

detailed

control,

a

class

of

particles

containing

both

mineral and gangue (middling particles) are also produced. The smaller the percentage of middling the greater the degree of

liberation. Comminution is divided into crushing (down to 6-to 14-mush) and grinding (down to micron size). Crushing is

usually done in three stages: coarse crushing from run-of-mine size to 4-6 in., or coarser; intermediate crushing down to

about 1/2 in.; and fine crushing to 1/4 in. or less. Screen is a method of sizing whereby graded products are produced, the

individual particles in each grade being of nearly the same size. In beneficiation, screening is practiced for two reasons: as

and

integral

part

of

the

separate

on

process,

for

example,

in

jigging,

and

to

produce

a

feed

of

such

size

range

as

is

compatible with the applicability of the separation process.

Beneficiation

. This step consists of two fundamental operations: the determination that an individual particle is either

a mineral or a gangue particle (selection); and the movement of selected particles via different paths (separation) into the

concentrate

and

tailing

products.

2

When

middling

particles

occur,

they

will

either

be

selected

according

to

their

mineral

content and then caused to report as concentrate or tailing, or be separated as a third product (middling).

3

In the latter case,

the middling is reground to achieve further liberation, and the product is fed back into the stream of material being treated.

Selections based upon some physical or chemical property in which the mineral and gangue particles differ in kind or

degree or both. Thus in picking, the old form of beneficiation, color, luster, and shape are used to decide whether a lump of

ore is predominantly mineral or gangue. Use is made of differences in other physical or chemical properties, such as specific

gravity,

magnetic

permeability,

inductive

charging

(electrostatic

separation),

surface

chemical

properties,

bulk

chemical

properties,

weak

planes

of

fracture

(separation

by

screening),

and gamma-ray

emission

(automatic

sorting

of

radioactive

nature).

Separation is achieved by subjecting each particle of the mixture to a set of forces that is usually the same irrespective

of the nature of the particles excepting for the force based upon the discriminating property. This force may be present for

both mineral and gangue particles but differing in magnitude, or it may be present for one type of particle and absent for the

other. As a result of this difference separation is possible, and the particles are collected as concentrate or tailing.

Magnetic

separation utilizes

the

force exerted by

a

magnetic

field

upon

magnetic

materials

to

counteract

partially

or

wholly the effect of gravity. Thus under the action of these two forces different paths are produced for the magnetic and

nonmagnetic particles.

Gravity concentration is based on a discriminating force, the magnitude of which varies with specific gravity. The other

force that is usually operating in gravity methods is the resistance to relative motion exerted upon the particles by the fluid

or semi-fluid medium in which separation takes place

Jigging is a gravity method that separates mineral from gangue particle by utilizing an effective difference in settling

rate through a periodically dilated bed. During the dilation heavier particles work their way to the bottom while the lighter

particles

remain

on

top

and

are

discharged

over

the

lip.

Jigging

is

practiced

on

materials

that

are

liberated

upon

being

reduced to sizes ranging from 3/2 in., down to several millimeters. It has been used on such diverse ores as coal, iron ores,

gold and lead ores.

Tabling is a gravity method in which the feed, introduced onto an inclined plane and reciprocated deck, moves in the

direction of motion while simultaneously being washed by a water film which moves it also at right angles to the motion of

the

deck.

4

The

heavier

mineral

and

the

lighter

gangue

are

usually

collected

over

the

edges

of

the

deck.

The

boundary

between the heavier mineral and lighter gangue particles is roughly a linear diagonal band on the deck of the table. This

diagonal band is not stationary; rather it tends to

move about a mean position. In practice therefore, a third product, the

middling, is collected between the discharge edges of concentrate and gangue. If the feed to the table has been crushed or

ground to produce liberation, then the middling is returned to the feed. If liberation has not been achieved, the middling is

returned to the crushing-grinding section of the mill. Tables may be used to treat relatively coarse material (sand tables)

with sizes ranging from about 2~3 mm down to 0.07 mm.

Sink-float separation is the simplest gravity method and is based on existing differences in specific gravity.

The feed

particles are introduced into a suspension, the specific gravity of which is between that of the mineral and gangue particles,

with the result that particles of higher specific gravity sink while those of lower specific gravity float.

5

The separator is a

cone equipped with a slowly operated stirrer which serves to impart slow rotary motion to the suspension and prevent the

suspension from settling out on the walls. Feed is introduced at one point of the circumference and is slowly moved by the

rotating motion of the suspension. By the time this material has reached the discharge point on the circumference, those

particles whose specific gravity is greater than that of the suspension have moved down through the suspension so that only

float particles are discharged at the top, the sink particles are discharged at the bottom.

Flotation is used to separate valuable minerals from waste rock or gangue, in which the ground ore is suspended in

3

water and, after chemical treatment, subjected to bubbles of air. The minerals that are to be floated attach to the air bubbles,

rise through the suspension, and are removed with the froth that forms on top of the pulp. Froth flotation was first used to

recover sulfide minerals that were too fine to be recovered by gravity concentrators such as jigs, tables, and sluices. Froth

flotation is also used to concentrate oxide minerals such as hematite (Fe

2

O

3

) and pyrolusite (MnO

2

), and native elements

such

as

sulfur,

silver,

gold,

copper

and

carbon

(both

graphite

and

diamond).

Froth

flotation

is

also

used

to

separate

the

silicate minerals.

4

Lesson 5

Materials Science and Engineering

Embrace

包括

PVC

聚氯乙烯

Ceramics

陶瓷

Polyethylene

聚乙烯

Inanimate

无生命的

PTFE

聚四氟乙烯

Homogeneous

均匀的

Terylene

涤纶

Predominate

主导

nylon

尼龙

Rigidity

刚性

leather

皮革

Weldability

可焊性

reinforced

增强

Composite

复合材料

dispersion

弥散

Spectrum

种类

supersonic

超声波

Brass

黄铜

optimum

最优

Bronze

青铜

fabrication

人工制作

Invar

因钢

(NiFe)

invariable

不变的

Cement

水泥

corrosion

腐蚀

Ferrite

铁素体

fatigue

疲劳

Garnet

石榴石

assess

评估

1.

Materials Science

“Materials Science” is a subject for engineers of the modern age. It embraces a study of different materials regarding

their structures, properties and uses. The “material” here does not refer to all matter in the Universe. If this were so, it

would

include all the physical sciences and the life sciences

form astronomy to zoology. We can restrict the definition only to

matter useful to mankind. Even here, the range is too broad for the purposes of the engineer. For example, we can list a large

number of things useful, to man, such as food, medicines, explosives, chemicals, water, steel, plastics and concrete, only a

few

of

which

qualify

as

engineering

materials.

We

have

then

to

be

more

specific,

and

define

materials

as

that

part

of

inanimate matter that is useful to the engineer in the practice of his profession.

1

Recently the term, materials refer only to

solid materials, even though it is possible to quote a number of examples of liquid and gaseous materials such as sulfuric

acid and steam, which are useful to the engineer.

The word ‘science’ refers to the physical science, in particular to chemistry and physics. As we confine ourselves mainly

to solid in material science, the subject is related to solid state chemistry and solid state physics. The engineering usefulness

of

the

matter

under

study

is

always

deep

in

mind.

In

this

respect,

material

ceramics

science

comes

heavily

from

the

engineering sciences such as metallurgy, and polymer science. These, in their own time, have grown out of their interaction

with the basic sciences of chemistry and physics.

Therefore,

Material

Science

refers

to

that

branch

of

applied

science

concerned

with

investigating

the

relationship

existing between the structure of materials and their properties, and it concerns with the interdisciplinary study of materials

for

entirely

practical

purposes.

2

Material

science

has

developed

rapidly

during

the

last

ten

years.

The

new

approach

of

material science has paid of handsomely in many ways and they have solved the problems in selection of right materials in

complex situations.

2. Classes of Engineering Materials

Within the scope of material science, the engineering materials

may be classified in three broad groups according to

their mode of occurrence:

(1)

Metals and alloys

(2)

Ceramics

(3)

Organic polymers.

A

metal

is

an

elemental

substance.

An

alloy

is

a

homogeneous

mixture

of

two

or

more

metals

or

a

metal

and

nonmetal.

Among

the

solid

materials,

metals

and

alloys

predominate

because

of

their

useful

characteristics

of

hardness,

strength, rigidity, formability, machinability, weldability, conductivity and dimensional stability.

Ceramics

are

materials

consisting

of

phases.

A

phase

is

a

physically

separable

and

chemically

homogeneous

constituent of a material. These are themselves compounds of metallic and non-metallic elements. All metallic compounds,

rocks minerals, glass, glass-fiber, abrasives and all fired clays are ceramics.

5

Organic

materials

are

those

materials

derived

directly

from

carbon.

They

usually

consist

of

carbon

chemically

combined

with

hydrogen,

oxygen

or

other

nonmetallic

substances,

and

their

structures

are,

in

many

instances,

fairly

complex. Plastics and synthetic rubbers are common organic engineering materials.

Table 1 shows a broad spectrum of engineering materials which shows not only typical examples from each of these

three groups but also gives a number of examples of materials which are composite up of two groups.3 In general, in each

and every engineering application we find material from all the three basic types of materials described above.

Table 1. Some important grouping of materials

Group of materials

Common examples of engineering use

(4) Composite

①

Metals, alloys

and ceramics

②

Metals, alloys and/

or organic polymers

③

Ceramics and

organic polymers

?

?

㏒?

?

?

琰茞

?

?

?

Steel-reinforced concrete,

Dispersion-hardened alloys

Vinyl-coated steel,

whisker- reinforced plastics

Fiber- reinforced plastics,

carbon- reinforced rubber.

Since the engineer must specify the materials for TV sets, computers, suspension bridges, oil refineries, rocket motors,

nuclear

reactors,

or

supersonic

transports

he

must

have

sufficient

knowledge

to

select

the

optimum

material

for

each

application.

Although

experience

provides

the

engineer

with

a

starting

point

for

selection

of

materials,

the

skill

of

the

engineer will be limited unless he understands the factors that contribute to the properties of materials.4

3. Selection of Materials

Right type of material is to be selected for a particular type of work. The selections of the right materials for given

requirements, the proper use of those materials, development of new ways of using them for greater effectiveness, all are

direct responsibility of the engineer.

To fulfill this responsibility, the engineer must have a thorough knowledge of the nature and behavior of materials. The

study of the nature of materials has its foundation in chemistry and physics and that of behavior of materials involves the

application, of the principles of the nature of materials, under the varied conditions found in engineering practice.3 This

behavior

of

materials

is

determined

by

composition,

structure,

service

conditions,

and

the

interactions

among

them.

All

materials have limitations within which they perform well but beyond which they cannot be used satisfactorily.

However,

the

selection

of

a

material

for

a

specific

application

is

invariably

a

thorough,

lengthy,

and

expensive

investigation. Almost always more than one material is suited to the application, and the final selection is a compromise that

weights

the

relative

advantages

and

disadvantages.

The

varied

requirements

to

three

broad

demands:

(1) Service

requirements; (2) Fabrication requirements; (3)

Economic requirements.

The service requirements have important role in material selection. The material must stand up to service demands.

Such demands commonly include dimensional stability, corrosion resistance, adequate strength, hardness, and toughness,

heat

resistance.

In

addition

to

any

such

basic

requirements,

other

properties

may

be

required

such

as

a

low

electrical

resistance, high or low heat conductivity, fatigue resistance, or others.

Fabrication requirements are also to be considered in material selection. It must be possible to shape the material, and

to join it to other material. The assessment of fabrication requirements concerns questions of machinability, hardenability,

heat treatability, ductility, castability, and weldability, qualities that are sometime quite difficult to assess.

Along with the above two requirements, the economic requirements give final shape in material selection. Goods must

be

produced

at

lower

cost. The

object

is

the

minimum

over

all

cost

of

the

component

to

be

made,

and

this

objective

is

sometimes attained only by increasing one or more of the cost components

6

Lesson 6

Metallurgy

n.

冶金，冶金学

Non- ferrous metallurgy

有色冶金学

Chlorine metallurgy

氯化冶金学

Powder metallurgy

粉末冶金学

Extractive metallurgy

提取冶金学

Meteoric iron

陨铁

Craftsmanship

n.

手艺，技能

Craftsman

n.

技工，工匠

Ornamental

adj.

装饰用的，观赏的

n.

装饰品

Metalworking

n.

金属加工

Ceremonial

adj.

正式的，礼仪的，仪式的

Decorative

adj.

装饰的

Decorative arts

装饰艺术

Cast

n.

v.

铸造，铸件

Process metallurgy

过程冶金

Production metallurgy

生产冶金

Physical metallurgy

物理冶金

Chemical metallurgy

化学冶金

Mechanical metallurgy

机械冶金，力学冶金

Unit operation

单元操作

Unit process

单元过程

Flux

n.

熔剂

Solvent

n.

溶剂

Slag

n.

渣，炉渣

v.

造渣

Electrolyte

n.

电解质，电解液

Depletion

n.

用尽，消耗，贫化，提取金属

Deposit

n. v.

沉积，沉淀，电积

Blast furnace

鼓风炉，高炉

Crude iron

生铁

crystal structure

晶体结构

Metallurgy

neutron

n.

中子

diffraction

n.

衍射

crystal imperfection

晶体缺陷

plastic deformation

塑性变形

metallography

n.

金相学

microscopy

n.

显微镜学，显微技术

forging

n.

锻造，锻件

blowhole

n.

气孔

thermodynamics

n.

热力学

kinetics

n.

动力学

Steelmaking

n.

炼钢

Scrape

n.

废料

Leach

v.

浸出，溶出

Electrochemical reduction cell

电化学还原电池

Inorganic chemistry

无机化学

Pyro-metallurgy

火法冶金

Hydro- metallurgy

湿法冶金

elevated temperature

高温

reduce

v.

还原

reduction

n.

还原

charcoal

n.

木炭，炭

spontaneous

adj.

天然的，自动的，自发的

residue

n.

残渣，剩余物，残余物，炉渣

roasting

n.

焙烧

pig iron

粗铁，生铁

refine

v.

n.

精炼，提纯，纯化

uranium

n.

铀

tungsten

n.

钨

molybdenum

n.

钼

isolate

v.

隔离，隔绝，切断

recovery

n.

回收，回收率，回复，恢复

7

scope

n.

范围，领域，目标

amenability

n.

可控制性，可处理性

revert

n.

返料

adaptability

n.

适应性

metalloid

n.

类金属

adj.

类金属的

hafnium

n.

铪

selenium

n.

硒

zirconium

n.

锆

tellurium

n.

碲

flexibility

n.

适应性，灵活性

Metallurgy is the science of metallic materials. Metallurgy as a branch of engineering is concerned with the production

of metals and alloys, their adaptation to use, and their performance in service. As a science, metallurgy is concerned with

the chemical reactions involved in the processes by which metals are produced and the chemical, physical, and mechanical

behavior of metallic materials.

1

Metallurgy has played an important role in the history of civilization. Metals were first produced more than 6000 year

age. Because only a few metals, principally gold, silver, copper and meteoric iron, occur in the uncombined state in nature,

and then only in small quantities, primitive metallurgists had to discover ways of extracting metals from their ores. Fairly

large-scale production of some metals was carried out with technical competence in early Near Eastern and Mediterranean

civilizations and in the Middle Ages in central and northern Europe. Basic metallurgical skills were also developed in other

parts of the world.

The winning of metals would have been of little value without the ability to work them. Great craftsmanship in

metalworking developed in early times; the objects produced included jewelry, large ornamental and ceremonial objects,

tools and weapons. It may be noted that almost all early materials and techniques that later had important useful applications

were discovered and first used in the decorative arts.

2

In the Middle Ages metalworking was in the hands of individual or

groups of craftsmen. The scale and capabilities of metalworking developed with the growth of industrial organizations.

Today’s metallurgical plants supply metals and alloys to the manufacturing and construction industries in many forms such

as beams, plates, sheets, bars, wire, and castings. Rapidly developing technologies such as communications, nuclear power,

and space exploration continue to demand new techniques of metal production and processing.

The

field

of

metallurgy

may

be

divided

into

process

metallurgy,

(production

metallurgy,

extractive

metallurgy)

and

physical metallurgy. According to another system of classification, metallurgy comprises chemical metallurgy, mechanical

metallurgy (metal processing and mechanical behavior in service), and physical metallurgy. The more common division into

process

metallurgy

and

physical

metallurgy,

which

is

adopted

here,

classifies

metal

processing

as

a

part

of

process

metallurgy and the mechanical behavior of metals as a part of physical metallurgy.

Process metallurgy

Process metallurgy, the science and technology used in the productions of metals, employs some

of the unit operations and unit processes as chemical engineering. These operations and processes are carried out with ores,

concentrates, scrap metals, fuels, fluxes, slag, solvents, and electrolytes. Different metal adopts different combinations of

operations and processes, but typically the production of a metal involves two major steps. The first is the production of an

impure metal from ore minerals, commonly oxides or sulfides, and the second is the refining of the reduced impure metal,

for

example,

by

selective

oxidation

of

impurities

or

by

electrolysis.

Process

metallurgy

is

continually

challenged

by

the

demand for metals that have not been produced previously or are difficult to produce; by the depletion of the richer and

more easily processed ores of the traditional metals; and by the need for metals of greater purity and higher quality. The

mining of leaner ores has greatly enhanced the importance of ore dressing methods for enriching raw materials for metal

production. Several nonferrous metals are commonly produced from concentrates. Iron ores are also increasingly treated by

ore dressing.

Process metallurgy today mainly involves large scale operations. A single blast furnace produces crude iron at the rate

of

3,00~11,000

tons

per

day.

A

basic

oxygen

furnace

for

steelmaking

consumes

800

tons

of

pure

oxygen

together

with

required amounts of crude iron and scrap to produce 12,000 tons of steel per day. Advanced methods of process analysis and

control are now being applied to such processing system. The application of vacuum to extraction and refining processes,

the leaching of low-grade ores for the extraction of metals, the use of electrochemical reduction cells, and the refining of

reactive metals by processing through the vapor state are other important developments.

Because the production of metals employs many different chemical reactions, process metallurgy has been closely

associated with inorganic chemistry. Techniques for analyzing ores and metallurgical products originated several centuries

ago and represented an early stage of analytical chemistry. Application of physical chemistry to equilibrium and kinetics of

metallurgical reactions has led to great progress in metallurgical chemistry.

According to temperature at which the process is carried out process metallurgy may be divided into pyrometallurgy

and hydrometallurgy. Pyrometallurgy is processes employing chemical reactions at elevated temperatures for the extractions

of metals from ores and concentrates. The use of heat to cause reduction of copper ores by charcoal dates from before 3,000

B.C. The techniques of pyrometallurgy have been gradually perfected as knowledge of chemistry has grown and as sources

of controlled heating and materials of construction for use at high temperature have become available.

3

Pyrometallurgy is

the principal means of metal production.

8

The advantages of high temperature for metallurgical processing are several: chemical reaction rates are rapid, reaction

equilibriums change so that processes impossible at low temperature become spontaneous at higher temperature, and

production of the metal as liquid or gas facilitates physical separation of metal from residue.

4

The processes of pyrometallurgy may be divided into preparation processes which convert the raw material to a form

suitable for further processing (for example, roasting to convert sulfides to oxides), reduction processes which reduce

metallic compounds to metal (the blast furnace which reduces iron oxide to pig iron), and refining processes which remove

impurities from crude metal (fractional distillation to remove iron, lead, and cadmium from crude zinc).

The complete production scheme, from ore to refined metal, may employ pyrometallurgical processes (steel, lead, tin,

zinc), or only the primary extraction processes may be pyrometallurgical, with other methods used for refining (copper,

nickel).

5

In some case (uranium, tungsten, molybdenum), isolated pyrometallurgical processes are used in a treatment

scheme that is predominately nonpyrometallurgical.

Hydrometallurgy is the extraction and recovery of metals from their ores by processes in which aqueous solutions play

predominant role. Two distinct processes are involved in hydrometallurgy; putting the metal values in the ore into solution

via

the

operation

known

as

leaching;

and

recovering

the

metal

values

from

solution,

usually

after

a

suitable

solution

purification or concentration step, or both. The scope of hydrometallurgy is quite broad and extends beyond the processing

of ores to the treatment of metal concentrates, metal scrap and revert materials, and intermediate products in metallurgical

processes.

Hydrometallurgy

enters

into

the

production

of

practically

all

nonferrous

metals

and

or

metalloids,

such

as

selenium and tellurium.

The advantages of hydrometallurgy are applicability to low-grade ores (copper, uranium, gold, silver), amenability to

the treatment of materials of quite different compositions and concentrations, adaptability to separation of highly similar

materials (hafnium from zirconium), flexibility in terms of the scale of operations, simplified materials handling as

compared with pyrometallurgy, and good operational and environmental control.

Physical metallurgy investigates the effects of composition and treatment on the structure of metal and the relations of

the structure to the properties of metals. Physical metallurgy is also concerned with the engineering applications of scientific

principles to the fabrication, mechanical treatment, heat treatment, and service behavior of metals.

The

structure

of

metals

consists

of

their

crystal

structure,

which

is

investigated

by

x-ray,

electron,

and

neutron

diffraction,

their

microstructure,

which

is

the

subject

or

metallography,

and

their

macrostructure.

Crystal

imperfections

provide mechanisms for processes occurring in solid metals, for example, the movement of dislocations results in plastic

deformation.

Crystal

imperfections

are

investigated

by

x-ray

diffraction

and

metallographic

methods,

especially

electron

microscopy.

The

microstructure

is

determined

by

the

constituent

phases

and

the

geometrical

arrangement

of

the

microcrystals

(grains)

formed

by

those

phases.

Macrostructure

is

important

in

industrial

metals.

Phase

transformations

occurring

in

the

solid

state

underlie

many

heat-treatment

operations.

The

thermodynamics

and

kinetics

of

these

transformations are a major concern of physical metallurgy. Physical metallurgy also investigates changes in the structure

and properties resulting from mechanical working of metals.

9

Lesson 12

Calcination and Roasting

Calcination n.

焙烧，煅烧

smelt

n. v.

熔炼

calcine

焙砂

noble

adj.

贵重的，惰性的

Decomposition

n.

分解，裂解

noble metal

惰性金属，贵金属

Metal hydrate

金属氢氧化物

hypothetical

adj.

假定的，有前提的

Carbonate

n.

碳酸盐

fume

n.

烟气

Basic sulphate

碱式硫酸盐

halide

n.

卤化物

Rotary kiln

回转窑

volatilizing roast

挥发焙烧

Shaft furnace

竖炉

magnetizing roast

磁化焙烧

Dead roasting

死烧

magnetite

n.

磁铁矿

Sulphating roasting

硫酸化焙烧

flash roaster

闪速焙烧炉

,

飘悬焙烧炉

Reduction roasting

还原焙烧

inject

v.

喷射，喷入

equillibrium constant

平衡常数

fluidise

v.

流态化

kellog diagram

凯洛格相图

fluidized bed roaster

流态化焙烧炉

predominance

n.

优势，优越

burner

n.

喷嘴

predominance

area

优势区

suspend

v.

悬浮，漂浮

partial roasting

部分焙烧

fluo-solids roaster

流化

-

< p>
闪速焙烧炉

selective roasting

选择性焙烧

matte

n.

冰铜，锍

chloridizing roast

氯化焙烧

reverberatory furnace

反射炉

1. Calcination

Calcination involves the chemical decomposition of the mineral and is achieved by heating to above the mineral’s

decomposition temperature (T

D

) or by reducing the partial pressure of the gaseous product (P

H

2

O

, P

CO

2

) below that of its

equilibrium partial pressure for a certain constant temperature.

1

For example,

CaCO

3

= CaO + CO

2

T

D

= 900

℃

(under standard thermodynamic conditions)

Calcination is mainly used to remove water, CO

2

and other gases which are chemically bound in metal hydrate and

carbonates as these minerals have relatively low decomposition temperatures.

2

Calcinations are conducted in rotary kilns, shaft furnaces or fluidized bed furnaces.

2. Roasting of metal concentrates

The

most

important

roasting

reactions

are

those

concerning

metal

sulfide

concentrates

and

involve

chemical

combination with the roasting atmosphere.

Possible reactions include:

MS + 3O

2

= 2MO + 2SO

2

(dead roast)

MS + 2O

2

= MSO

4

(sulfating roast)

MS + O

2

= M + SO

2

(reduction roast)

Other equilibria which need to be taken into account include:

(1/2)S

2

+ O

2

= SO

2

and

SO

2

+ (1/2)O

2

= SO

3

Thus, when P

SO

2

is large and P

S

2

become large. Also when P

O

2

and P

SO

2

become large, P

SO

3

become large which is the

required condition for sulfating roasting; the sequence of reactions being

MS + (3/2)O

2

= MO + SO

2

SO

2

+ (1/2)O

2

= SO

3

MO + SO

3

= MSO

4

10

Fig. 12-1 Hypothetical thermodynamic phase diagram for the roasting

of a metal sulfide concentrate at a constant temperature

giving the overall sulfating reaction:

MS + 2O

2

= MSO

4

If the metal forms several sulfides, oxides, sulfates and basic sulfates, e.g. M

2

S, M

2

O

3

, M

2

(SO

4

)

3

, MSO

4

, XMO

3

further equilibria must be considered. By examination of the equilibrium constant for each of these roasting reactions it is

possible to determine the values of P

O

2

and P

SO

2

at which each of the roasting products (calcine) is in equilibrium with the

metal sulfide at a constant temperature. Increasing or decreasing the P

O

2

or P

SO

2

may produce other roasting reactions.

Kellog has used this criterion to construct thermodynamic phase diagrams for the roasting reactions at a constant

temperature (Fig. 12-1). Reactions which involve both SO

2

and O

2

are seen to have a diagonal line since the equilibrium

phases produced will depend on the partial pressure of both gases. The roasting of a metal sulfide to a sulfate or a basic

sulfate will produce a vertical reaction line since only O

2

will take part in the reaction. The ‘Kellog diagram’ provides the

predominance areas for each phase within which P

O

2

and P

SO

2

can be varied without altering the roasting product or calcine.

It should be noted that if roasting is carried out in air the sum of the partial pressure of O

2

and SO

2

is about 0.2 atm, i.e.

P

O

2

+ P

SO

2

= 0.2 atm..

The ore concentrate will undoubtedly contain other metal sulfide each with their own phase predominance areas

dependent upon P

O

2

, P

SO

2

and temperature. By examination of the appropriate diagrams it is possible to obtain information

which will enable the roasting operator to select the most appropriate roasting conditions for each particular concentrate. In

this way selective roasting of one metal sulfide to its oxide may be achieved while another metal present in the concentrate

remains as the sulfide.

A dead roast is used when the metal oxide is to be reduced by carbon or hydrogen. A sulfating roast is used when the

metal sulfate is subsequently leached with a dilute sulfuric acid solution. Metal sulfates decompose at low temperatures,

therefore sulfating is normally conducted at about 600~800

℃

, i.e. below the corresponding decomposition temperature,

with a restricted amount of air, while dead roasting is conducted at 800~900

℃

with excess air, i.e. a high P

O

2

/ P

SO

2

ratio.

Differential sulfating roasting is possible by operating at a temperature which will decompose one sulfate but not

another.

4

Thus, roasting a Ni

3

S

2< /p>

—

FeS concentrate at 850

℃

will produce NiSO

4

and Fe

2

O

3

since Fe

2

(SO

4

)

3

will

decompose at this temperature, i.e. Fe< /p>

2

(SO

4

)< /p>

3

=Fe

2

O

3

+ 3SO

3

. Reduction roasts are generally rare since this reaction usually

requires very low P

O

2

values and high temperatures is demanded by the thermodynamic considerations.

Other roasting reactions include:

⑴

Chloridizing roast which is generally used for the conversion of a reactive metal such as Ti, Zr, U, which form

extremely stable oxides, to a less stable chloride or other halide. The halide is relatively easy to reduce with another element

which forms more stable halide.

⑵

V

olatilizing roasts remove volatile impurity elements and oxides such as Cd, As

2

O

3

, Sb

2

O

3

, ZnO. These may be

recovered from the process fume using bag filters.

⑶

Magnetizing roast using controlled reduction of hematite (Fe

2

O

3

) to magnetite (Fe

3

O

4< /p>

) which can be subsequently

magnetically separated from the gangue.

The roasting reactions are gas

—

solid reactions and therefore rely on the diffusion of oxygen into and sulfur dioxide out

of each concentrate particle.

Reducing the particle size (less than 6 mm) improves the gas

—

solid contact and increases throughput. This principle is

used in the modern flash roasters in which preheated ore particles are injected through a burner with air, and fluidized bed

roasters in which the fine ore particles are suspended in the roasting gas. A development which incorporates both these

principles is the fluo

—

solids roaster in which air and ore fines are injected into the side of a reactor and fluidized by an

upward draught of preheated (500

℃

) air.

It has been claimed that the fluo

—

solids roaster offers certain advantages over the multihearth unit for the partial

roasting of Cu

2

O ores. Such advantages include greater control over sulfur elimination, less space and operating labor

required, it is more amenable to automation and a higher quality matte from the reverberatory furnace is produced.

5

11

12

Lesson 13

Mattes

Ionic

adj.

离子的

Immiscible

adj.

不能混合的，互不溶解的

Straightforward smelting

直接熔炼，连续熔炼

Soda ash

纯碱，碳酸钠

Gypsum

n.

石膏

Ternary

adj.

三元的

Eutectic structure

共晶结构

Ternary eutectic

三元共晶

Deviation

n.

偏差，偏离

positive deviation

正偏差

negative deviation

负偏差

Raoult

’s law

拉乌尔定律

Pseudo

假，伪，准，似

Terminal

adj.

n.

极限（的）

< br>，终点（的）

，终端（的）

Solidify

v.

固化、凝固，变硬

Feature

n.

特征，性能

Partition

n.

v.

分配，分布，分隔，隔板

Availability

n.

可得到，存在，现有

Balance

n.

平衡，均衡

Antimony

n.

锑

Preferential oxidation

优先氧化

Convert

v.

吹炼

1. Mattes

Mattes are solution of metallic sulfides. They have electrical conductivities suggesting that their structures, when molten,

are ionic or possibly partly metallic.1 They have rather lower melting

—

point ranges than slags. They are much denser than

slags (specific gravity about 5 for matte and 3 for slag) and they are immiscible in both slag and metal phases, though either

can dissolve sulfur. Mattes are used either for the collection of the valuable mineral in a straightforward smelting process

(Cu, Ni) or for the collection of impurities in a sulfide phase from which the principal metal (e.g. Sb) has been displaced by

Na, charged as soda ash (Na

2

CO

3

). Oxide ores can be smelted to matte with pyrites or gypsum as the source of sulfur but

this is rare.

The copper mattes, which are by far the most important commercially, have been well discussed by Ruddle. Referring to the

Cu

—

< br>Fe

—

S

ternary

diagram

(Fig.

13-1)

the

copper

—

iron

mattes

are

found

in

a

narrow

band

of

composition

running

between the FeS and Cu2S compositions. Cu2S is immiscible in Cu but FeS is soluble in iron, the solution having, however,

very marked positive deviation from Raoult’s law so that it is not surprising that a wide band of immiscibility separates the

Fe

—

Cu edge of the diagram from the FeS

—

Cu2S band in which the mattes lie.2

Within this band several workers have detected an eutectic structure, but the actual eutectic point lies off the FeS

—

Cu2S

join to the side of rather higher sulfur content and it is in fact a ternary eutectic.

The activities along the pseudo

—

binary join between Cu2S and FeS have been determined. Both species show small

deviations from Raoult’s law, negative in the case of Cu

2

S and positive in the case of FeS, but this latter observation has

been disputed. Most commercial mattes, however, contain rather less sulfur than that required to provide a mixture of the

two

terminal

sulfides

and

the

true

eutectic

would

be

obtained

only

under

a

sulfur

pressure

that

is

rather

higher

than

atmospheric.

3

Mattes usually contain some oxygen and experimental work on mattes should be carried out under controlled oxygen

pressure as well as sulphur pressure. Analysis for oxygen in mattes is not easy as it is essentially a determination of the state

of combination of iron in a sample which is usually rather difficult to dissolve without using an oxidizing agent.

In low

—

grade mattes made under reducing conditions in blast furnace iron may be present as the metal with FeS and

Cu2S.

High

—

grade

commercial

matte

may

contain

F

eS?Cu

and Cu

2

S

if

made

under

reducing

conditions.

Reverberatory

mattes made under an oxidizing atmosphere and slag may solidify with up to 20% of Fe

3

O

4

and a small amount of FeO but

the state of the iron in the melt is not apparently know.

4

The solubility of Fe3O4 in copper

—

iron mattes may be about 30%

(12% oxygen) in very lean matte (i.e. one which is high in FeS and low in Cu

2

S) but decreases rapidly as the copper content

increase. The precipitation of magnetite in reverberatory hearths and in converters as iron is oxidized out of the matte and

slgged (so increasing the Cu content and lowering the solubility of the Fe

3

O

4

) is a well

—

known feature of these processes

which gives a great deal of trouble.

13

The copper content (“grade”) of a copper matte depends

on the Cu/Fe ratio and on the O/S ratio of the concentrate of

calcine being smelted. All of the copper present goes into the matte but the iron is partitioned between matte and slag in

proportions

which

are

determined

by

the

availability

of

sulfur

and

oxygen.

Sufficient

iron

and

sulfur

must

be present

to

provide enough FeS to protect the copper in the matte from oxidation. Low

—

grade matte can have as little as 20% Cu (25%

Cu2S) but normally the grade is higher with about 45% Cu (55% Cu2S), the balance being mainly FeS with iron oxide in

solution.

5

Mattes also collect a number of other metals besides iron and copper, particularly nickel, cobalt, zinc and lead, gold,

silver

and

platinum

metals.

Nickel

—

copper

—

iron

mattes

are

produced

from

nickel

ores

and

are

converted

into

copper

—

nickel

mattes

during

nickel

extraction,

i.e.

FeS

is

blown

out,

Cu2S

and

Ni3S2

form

an

eutectic

which

can

be

produced coarse enough for the constituents to be separated by flotation after crushing.

Mattes

are

important

only

in

the

extraction

of

copper,

nickel

and

sometimes

antimony.

In

lead

smelting

copper

is

collected

in

a

matte

in

the hearth,

a

controlled

quantity

of

sulfur being

included

in

the

charge

for

the

purpose.

Sulfur

is

partitioned between the matte and and any metallic phase present with a small amount also entering the slag. Oxygen and

iron are partitioned between the matte and any slag in the system. Mattes are intermediate products and the distinct lack of

knowledge about them is partly due to this fact, partly to the difficulty of investigating them, and partly to the fact that in the

next stage of their processing, conversion, the problems encountered are not primarily connected with matte constitution

and structure.6

The

product

of

matte

smelting

provides

the

metal

to

be

extracted

in

the

form

of

a

concentrated

metal

sulfide

which

needs to be converted to the metal.

Converting of the sulfide matte is achieved by blowing air and/or oxygen through the liquid matte effecting preferential

oxidation

of

the

more

reactive

impurity

metal

sulfides,

e.g.

MeS

to

their

respective

oxides

which

are

collected

in

an

appropriate slag:

2MeS + 3O

2

= 2MeO + 2SO

2

(impurity sulfide)

(impurity oxide)

The is normally conducted in a horizontal converter having tuyeres along one side. The air blowing is controlled to convert

the remaining more noble metal (less stable metal oxide) to the required metal, i.e.

MS + O2 = M + SO

2

Owing to the larger volume of MS present compared with impurity metal sulfides, oxidation of MS to MO will take place

initially followed by a mutual reduction reaction between MS and MO:

MS + 2MO = 3M + SO

2

In practice this is achieved by adding more MS to the converter or lower P

O2

. Thus, oxidation of a metal sulfide to its metal

is only possible where the mutual reduction reaction has a negative free energy change.

Fig. 13-1 The Cu

—

Fe

—

S phase diagram showing the composition ranges

in which typical copper mattes are found

14

Lesson 14

Slags

gaseous atmosphere

气氛

amphoteric

a.

两性的

thermal

barrier

隔热层

undissociated

a.

未离解的

interface

n.

分界面，接口，边界，界面

pentoxide

n.

五氧化物

fluorspar

n.

英石，氟石

appoach

n.

方法，途径，处理

sole

a.

唯一的，单独的

basicity

n.

碱性，碱度

trap

v.

捕获，收集

invalid

a.

无效的，不成立的

rate- controlling factor

速度控制因素

survey

v.

检查，调查，评价

orthosilicate

n.

原硅酸盐

interpretation

n.

解释，分析

acid slag

酸性渣

desulphurization

n.

脱硫作用

basic slag

碱性渣

self-consistent

前后一致的，独立的

neutralization

n.

中和

Slags,

which

consist

primarily

of

oxides,

are

used

in

most

pyrometallurgical

processes

—

that

is

processes

involving

elevated temperatures and broadly covering extraction of metals such as iron, zinc and lead using a reducing agent such as

carbon, refining by preferential oxidation (fire refining of copper and steelmaking) and matte smelting and conversion in the

extraction of copper and nickel from sulfides.

1

Slags fulfill two main functions

—

in extraction processes they take up the

gangue minerals which are not reduced to the metallic state and in refining processes they act as the receiver for unwanted

constituents of the metal. Iron provides a good example of both these functions the slag in the iron blast furnace contains the

gangue minerals such as silica, alumina and calcium oxide and, because it is liquid and separates easily from liquid iron,

provides a method of removing these waste materials from the furnace separately from the liquid metal.

2

The iron produced by the blast furnace contains up to 10% impurity elements by weight, and to convert this relatively

useless material into a purer alloy, steel, oxygen is introduced into the iron. Silicon and manganese are converted into oxides

which enter the steelmaking slag, and by suitable adjustment of the slag composition, sulfur and phosphorus may also be

removed from the liquid metal into the slag. Extraction slags can play a refining role

—

as in the iron blast furnace where

some sulfur is removed from the iron by the slag. Slags may also control the supply of oxygen, nitrogen, hydrogen and

sulfur from the gaseous atmosphere of a reverberatory furnace to the liquid metal and can act as thermal barriers where heat

is either leaving a liquid metal bath or entering it from a flame playing on the slag surface (open hearth steelmaking).

To allow these functions to be adequately fulfilled, slags must possess the following properties: they must be sufficiently

fluid to allow easy separation from the metal and to increase the rate of mass transfer to and from the slag/metal interface.

They must become fluid at a low enough temperature for the process to be worked economically with as little heat input and

refractory wear as possible

—

fluxes such as lime, quartz, fluorspar or iron oxide may be added solely to lower the liquidus

temperature and viscosity of slags. Their specific gravity must be sufficiently different from that of the metal to allow easy

separation. They must have the correct composition and structure to dissolve impurities and gangue minerals at low activity

and to allow any desired slag/metal reactions to occur.

The

structures

of

molten

oxides

were

mentioned

briefly,

and

as

silica

forms

the

basis

of

most

slags

being

the

commonest gangue constituent

—

we can form an initial picture of slags based on two types of oxide, RO and SiO

2

, where

RO

can

represent

any

of

the

oxide

CaO,

MnO,

MgO,

FeO,

ZnO,

PbO,

Cu2O,

Na

2

O,

K

2

O.

Ward

outlined

a

method

of

defining the composition of a slag in terms of the relative amounts of the two types of oxide, RO and SiO2. RO is called a

basic oxide because it provides oxygen ions when dissolved in a slag.

RO = R

2+

+ O

2-

Silica is an acidic oxide which will absorb oxygen ions provided by a basic oxide.

SiO

2

+ 2O

2-

= SiO

4

4-

An acid slag is one which contains more acidic oxide than the orthosilicate composition 2RO·

SiO

2

at which each silicon

4-

3

atom exists as a separate SiO

4

anion.

A basic slag contains more basic oxide than the orthosilicate composition and must

therefore contain excess oxygen ions which are not part of the silicate anion structure.

In slags, other acidic oxides than silica are present and their oxygen requirements must also be satisfied by the addition of

basic oxides before the slag becomes basic. For example, the neutralization of alumina and phosphorus pentoxide can be

represented by the equations:

Al

2

O

3

+ 3O

2-

= 2AlO

3

3-

P

2

O

5

+ 3O

2-

= 2PO

4

3-

And each molecule of alumina and phosphorus pentoxide would require three molecules of basic oxides to neutralize them.

This approach is useful in certain cases but it must be remembered that the picture is complicated by the tendency of some

oxides (Al

2

O

< p>
3

, Fe

2

O

3

, SnO2, ZnO and PbO) to behave amphoterically, that is as acidic oxides in basic slags and as basic

15