Download Document 8942350

FACULTY OF ENGINEERING AND THE BUILT ENVIRONMENT
Department of Chemical, Metallurgical and Materials Engineering
Metallurgical Engineering
Competition Day 6 May 2016
A MINERAL PROCESSING ADVENTURE: DESIGN AND BUILD A WORKING MODEL OF
FROTH FLOTATION PROCESS
1. INTRODUCTION
South Africa is a world leader in mining. It has the largest reserves of valuable minerals such as
platinum (Pt), manganese (Mn), gold (Au), base metals (copper (Cu), nickel (Ni), zinc (Zn), lead
(Pb) and iron (Fe)). Due to this, our country has become a powerhouse for innovation and a
pioneer for world-class mineral processing technologies. As a result, there has been a notable
interest in the study of various processing techniques which eventually become important tools
for a special class of engineers called Metallurgical Engineers.
In this science adventure, you will be introduced to basics of a classic process that Metallurgical
Engineers use to extract valuable minerals from various ore deposits which is widely known as
froth flotation. During flotation, the slurry (water + fine ore particles) is pumped into a flotation
cell and mixed with suitable chemicals (known as flotation reagents) as shown in Figure 1a. The
added chemicals then cause the valuable minerals to be “repelled” from water while those of
less value become “water loving”. What does this mean? What tricks do engineers use to extract
these metals when this happens?
At this stage, air is pumped into the flotation cell through the center of the agitator (a stirrer) and
causes the formation of bubbles. The “water repelled” minerals attach themselves to the bubbles
and rise to the upper level of a flotation cell and are then removed as froth ( - just like how
soap foam floats on water). Meanwhile, the “water loving” materials then settle at the bottom and
are then removed as the tailings. Refer to the Figures 1 and 2 below to better understand this
process.
a
b
Figure 1. Illustration of the froth flotation process showing: (a) a cross section of a flotation cell, (b) top
view of a flotation cell in the metallurgical plant (picture by www.911metallurgist.com; www.autotec.com).
1
Cleaners
Roughers
Figure 2. Froth flotation process in a Metallurgical plant (known as a Concentrator) showing flotation cells
connected in series (picture by www.e-mj.com ).
2. TEAM ASSIGNMENT
In this project, you are required to build a WORKING MODEL that will demonstrate a flotation
circuit consisting of FOUR flotation cells. Each cell must produce two streams from the feed
stream namely, the froth and tailings as shown on Figure 3a. The flotation circuit will be divided
into TWO sections consisting of two flotation cells. In a typical Concentrator plant, these
sections are commonly known as the roughers and cleaners which can be connected as
illustrated on Figures 2 and 3b.
Your model must demonstrate the feed, froth and tailings streams which shall be connected as
shown on Figure 3b. The flow of the slurry from one flotation cell to another must occur through
GRAVITY i.e. NO ELECTRICAL INSTRUMENTS MUST BE USED. For the construction of the
flotation vessels, the team can use any waste material (tins, tape, plastic, glue etc.) to ensure
that the model works properly. There are NO RESTRICTIONS on the SIZE but the flotation cells
must be similar in SHAPE.
2
a
Feed
material
(slurry)
Froth
(concentrate, rich in
valuable minerals)
Tailings
bb
Roughers
ROUGHERS
Feed
Cleaners
CLEANERS
Froth
Feed
Froth
R1
R1
C1
Froth
C1
Froth
Tailings
Tailings
Froth
Tailings
R2
Tailings
R1
Tailings
Froth
Froth
C2
C1
Tailings
Re-Cleaners
Tailings
Froth
Froth
RC 1
Froth
Tailings
Tailings
Froth
Tailings
Froth
Figure 3. The prescribed model RC
to be
2 constructed by the competing teams.
Froth
Tailings
3
3. MATERIALS
Teams are allowed to make use of any material to construct their model. However, any team
that will use vessels that were not handmade will be penalized or disqualified. The teams are
only allowed to purchase pipes that can be used for the process streams. Typical materials to
use include but not limited to:
 Glue, cans, plastic bottles, buckets, plastic pipes, slurry (which can be anything the
team choses) and other materials of choice.
 The team is allowed to use any kind of foam forming chemical
 The team is allowed to use any kind of material which can be used to demonstrate
the concept of separation by FLOATING and SINKING.
 The team is allowed to use any kind of material except paper, cardboard or cloth to
make vessels (this is so as to avoid leakages)
 The teams can put additional cells for the feed, tailings and froth streams to control
the flow.
 VERY IMPORTANT: THE FLOTATION CIRCUIT MUST BE ABLE HANDLE A
CONTINUOUS FLOW OF THE FEED MATERIAL.
4. RULES, SPECIFICATIONS AND OUTCOMES








Each team shall bring a finished model to TUT.
Teams may consist of a minimum of three and maximum of five learners.
Schools can enter only one team.
Each team will present a report which contains all the sketches, ideas, calculations,
test procedures and designs etc. which were used to decide on the final model.
The report will contain an indication of what the expected capacity (liters) that the
flotation model can treat.
TUT will provide two identical chairs or table where the model will be placed during
the competition. As for the slurry, TUT will only provide water upon request by the
team.
The built model will be tested for leakages using water by the TUT competition
officials. If there are any water leakages identified, points will be deducted from the
team.
Lastly, the team will then be allowed to illustrate the froth flotation processes and will
be judged on their presentation and functionality of their model.
5. LEARNING OBJECTIVES
This project will introduce the learner to the mineral processing fundamentals (in this case, froth
flotation), the design principles and operation of a metallurgical plant. The teams will learn the
basic calculations and procedures that engineers use when designing, starting and running a
metallurgical plant.
4
6. PROCEDURE
All teams must plan and build their projects in advance. If the project is transported to TUT in
parts, a maximum of 10 minutes will be allowed to set up your project. The place to set up your
project will be shown to you by competition officials.
7. TIME
There will be a time constriction of ten (10) minutes to set up the project.
8. EVALUATION
All teams will be judged based on the categories displayed in Table 1.
Table 1: The assessment criteria to be used for all the competing teams
ACTUAL
POINTS
CRITERIA
MAXIMUM
POINTS
COMMENTS
TEAM
Theme
5
Teamwork
5
PRESENTATION
Audibility
5
Content
15
Response to questions
10
Report
10
Appearance
10
Capacity
10
Functionality
30
MODEL
TOTAL
100
9. CONTACT DETAILS
CONTACT PERSON
Ms. Lerato Tshabalala
Ms. Innocentia Setlhabi
TEL
(012) 382 4244
(012) 382 4245
E-MAIL
[email protected]
[email protected]
5