3F03-Exam Review

Exam Review

April 2015

KC Availability: Exam review

• Tues April 7th11:00-1:00

• Wed April 8th 9:30-12:30

• Thurs April 9th 11:00-1:00

• Tues April 14 12:30-2:30

Exam Structure

• Four from eight questions.– One from Section 1 ( Process Design;heat &

mass balances)

• 3 hours

• No Books!

• Approved Calculator

Section

1;

Process

Design

Choice of at least one from two Questions

Will test ability to evaluate an select process options based on calculations of process performance; heat balance, mass balance equilibrium condition

Question 1/ Ironmaking and Iron Ore reduction Process

Question 2/ Design of Copper Making Process

Section

2;

Specific

Processes

Choose 3 from 6 questions testing knowledge of processes used to extract different metals and use theoretical background to analyse and evaluate these processes.

Content

• Everything up to and including Tues March 31

• Answers: – About 30-50% calculation– Will test application of concepts to designing

selecting processes.– Knowledge of Processes and understanding

basis of processes

Learning Objectives

• Thermochemical Fundamentals– Thermodynamics----Can we?---- How can

we?– Heat and mass balance---- how much

energy/product/raw material?

• Be aware of main processes used for materials production

• Be able to relate the design of these processes to the fundamentals.

What do we consider in design of process?

• Source of raw material

• Form/Chemistry of raw material– Accessibility of valuable content– Concentration of valuable content– Impurities– Chemical form of valuable content

(Oxide/Sulphide)

• Consistent supply

What do we consider in design of process?

• Heat requirement?

• Appropriate Fuels– Is the fuel also a reactant?– Does the ore provide its own fuel(Autogenous

processing of Sulphides)

• Economic productivity

• Value of product

• Required purity of product

Materials Processes

• Sulphide Smelting

• Reduction of Oxides in blast Furnace

• Molten Salt Electrolysis for Magnesium and Aluminum Production

Mass Balance

• Input =Output +Accumulation–Auditing of elements–Principle independent of chemical

changes–Ignores the interchange of energy–Applies to all processes regardless

of complexity

Heat Balance

• Similar to mass balance– Heat in=Heat out

+Accumulation

Stoichiometric coefficient –ve for reactants +ve for products.

i n

i HH 0

Heat Balance

• Phase transformation at T2

• Solid State, Melting, Vaporization, Sublimation

3

2

2

2

1

T

T

T

T

T

CpdTHCpdT

Heat of Reaction

reactf

prodfrxn HHH 298

dTCHHT

pT 298

0298

0

Heat Balance

• Critical Skills/Issues– Conduct Heat Balance With Multiple Inputs

and Outputs and Incomplete Chemical Reactions

– Calculate the heat of reaction at a new temperature

– Relate the outcomes of heat balance to why we do what we do in a process

Carbon Fuels

• Learning Objectives– Be able to discuss major characteristics of

metallurgical fuel– Be able to describe the coking process and

coal gasification.– Understand the properties we require from

coke and its role in the blast furnace

MS

MO2MSO

2 = 0.5S2 +O

2

Me

MeS

MeO

Process Red Metals M and Me

A/ can directly smelt both

B/ Can directly smelt M not Me

C/ Can directly smelt Me not M

D/ cant directly smelt either me or M

Process Blue Metals M and Me

A/ can directly smelt both

B/ Can directly smelt M not Me

C/ Can directly smelt Me not M

D/ cant directly smelt either me or M

0

0 log pO2

log

pS

2MS

MO2

M

SO2 = 0.5S

2 +O2

Me

MeS

MeO

A

B

C

2%M

O2

Sulphide Smelting

• Utopia– Continuous– Direct– Autogenous (utilize heat available from

sulphur combustion)– Zero Losses

Sulphide Smelting

• Reality– Most cannot be directly smelted– Those that can have major impurities that

prohibit the direct route– Different approaches– Ways of making continuous direct smelting

work

• Must be able to think of processing of all ores in terms of foregoing?

Sulphide Smelting Choice

• Lead sulphide can under certain circumstances be directly smelted.

You are asked to consider 2 concentrates:

A/ 50%PbS 50%FeS

B/ 90% PbS 10%FeS

Which will be the most appropriate for direct smelting

Sulphide Smelting Choice

You are have been asked to increase the purity of your lead Bullion, this will

A/increase lead losses

B/decrease lead losses

Which will be the most appropriate for direct smelting

Blast Furnaces

• Where the heat comes from– Importance of CO2 in off-gas

– Required properties of coke– Conditions required to make process work

• Desired and undesirable reactions

• Calculate required conditions

Copper

• Can Directly Smelt

• Major Impurity (FeS) Gets In the Way– Know the process routes and why?– Know the different types of furnace and their

characteristics/advantages

• Always a balance between purity, productivity and loss!

Flash Smelting of Copper

• Two concentrates

A/ 50%Cu2S 50% FeS

B/ 90%Cu2S 10% FeS

Which will be most amenable to Inco Flash Smelting?

Nickel

• Not Quite like Copper– Know the similarities and differences– Know the processing options– Know the equipment used– Know and understand the thermochemistry

Lead

• Also not quite like copper– Could directly smelt but there are challenges– Iron also plays a role

• Prefer blast furnace (not really)– Know the important reactions and where they

occur (desirable and undesirable)

Zinc

• Can’t Directly Smelt!• Big issue Gas Product!

– Understand complications– Understand thermodynamic solution– Understand kinetic solution

• Blast Furnace– How we avoid reoxidation– Important reactions– Lead splash condenser

Electrometallurgy

• Main Characteristics of System– How they affect process route (raw materials

treatment)– How they affect cell design

• e.g. density of electrolyte

• Energy optimization– Anode/cathode gap– Electrolyte properties– Production rate

Iron and Steelmaking

• Ironmaking Including the importance of Coke

• Steelmaking and process steps needed to remove specific impurities.

• Optimum process route for a specific steel