evaluation of dissolved air flotation for the treatment of minera
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flotationTRANSCRIPT
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Open Access Dissertations and Theses Open Dissertations and Theses
3-1-1982
Evaluation of Dissolved Air Flotation for theTreatment of Mineral SlimesAlan Jospeh Melnyk
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Recommended CitationMelnyk, Alan Jospeh, "Evaluation of Dissolved Air Flotation for the Treatment of Mineral Slimes" (1982). Open Access Dissertationsand Theses. Paper 3646.
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Evaluation of Di~solved Air Flotation,
for the Treatment of Mineral Slimes
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B.Eng. (McMaster University)
A Thellis
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Submitted to the Faculty, of Graduate Studies
in Partial Fulfilment of,.t.he R~quirements.
. for the Degree
,Master of ",Ene;Jineer.ing
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McMaster University
March 1982
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MASTER OF ENGINEERING(Chemical Engineering)
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McMASTER UNIVERSITYHamilton, Ontario
TITLE: EVALUATION OF DISSOLVED AIR FLOTATION FOR THETREA~ENT OF MINERAL SLIMES
AUTHOR: ALAN JOSEPH MELNYK. ,B. El!g. (McMaster lJ!liversity)
SUPERVISOR: Professor D. W. Woods
NUMBER OF PAGES: xi. ,209
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ABSTRACT
The recovery. of Ba'S04 mineral slimes (-10' inicrons) from silicausing dispersed and dissolved air flotation, was studied. Experiments
were performed in a modified commercial batch flotation machine. The
influence of flotation vari~bles such as collecto~c~ncentration,
concentration of silica depressant, pH, aeration and mineral purity on
"-;-_ flotation parameters were also examined.
Experimental eyidence suggests that dissolved air flotation results
in ,enhanced BaS04 r,e.covery over that normally achieved using dispersed
air, flotation for a limited range of elCperimental conditions. This
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range is character;zed by poor BaS04 flotation conditions such as low pH
or' collector concentration;' The flotation of BaS04 was found to be'
.strongly influenced by variables which regulate the surface chemistry of
the mineral, such as collector concentration, pH, .,silica depressant and
ml'neral purity. It was also speculated that D1echanical transfer or.
gangue into' the froth may be a critical factor :tn the upgrading of\" barite ores.
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ACKNOWLEDGEMENTS
I would like to express my sincere thanks to Dr. D. R. Woods
for his encouragement and effort during the course of this study.
I would like to thank Dr. Muthuswarni for his, informative
discussions.
The technical assistance of Mr. L. Suggett, Mr. H. Behrnann
and Mr. L. Salemi is also ~eatly appreciat~d.
Financial assistance provided by, McMaster University and the
National Science and Engineering Research Council ~~ appreciated.
I would also like to extend my sincere thanks to Valerie and
Henry Meng, Mehrnet Carnurdan, Kevin Smith, Mark costin and the
many other graduate students who hav~ provided invaluable friendship
over' the last two years. ,
Most of all, I would like to express my gratitude and appreciation
to my wife, Janet for her help and comfort
. "A. J. Melnyk
Hamilton, March 1982
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TABLE OF CONTENTS
1 INTRODUCTIO~ 1
l,i Treatment Difficulties 3.
1.2 S~rvey of New Slime Treatment 5Techniques
1. 2.1 Piggy Back Flotation 5
1.2.2 Electrophoresis 6
1.2.3 Magnetic and Electrostatic S~paration 7
1.2.4 -L~quid-Liquid Extraction1.2.5 Selective Flocculation
2 DISSOLVED AIR FLOTATION
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8
11
2.1 Mechanism and Factors Influencing 13Dissolved Air Flotation
2.1.1 Factor& Influencing the, Size and Rate 13of Precipitation of Air Bubbles
2.1.2 Factors Influen~ing the Attachment'of Precipitating Air to ~he MineralSurface
23
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2.1.3 Mineral Surface Activation byP~ecipitation of ~!ne Bubbles
3 EXPERIMENTAL APPROACH
2.2
3.1
3.2
Summary of a Pre~lous Investigation inDissolved Air'Flotation of MineralSlimes
f\ppar.atus
Experimen~al Procedure.
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4 RESULTS AND DISCUSSION ' 5~.
4.1 Introd\lction 54' .
4.2 D.A.F. 54
4.3 Collector Concentration 63
4.4 Depressant 69
4.5 purity of'BaS04 73
4.6 pH 76
4.1 Aeration 83
4.8 Celestite Flotation 93
5 CONCLUSIONS 100
References,
lOG.
Nomenclature 11QI Al DEVELOPMENT OF E~UATION TO PREDICT VOLUME OF 114
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AIR PRECIPITATINGFROM SOLUTION
A2 EXPERIMENTAL DETAILS 117
A2.a Expe~imental Procedure 118
A2.a.l Mineral Preparation 118 .
A2.a.2 Pre-Flotation Procedure 119
A2.a.3 Flotation Procedure 120
A2.a.4 Analysis of Flotation Products 121,
A2.b Equipment Description 122
A3 EXPERIMENTAL RESULTS I29
M STATISTICAL ANALYSIS 167
A4.a Estimate of Variance 168
M.b Hypothesis Tests 169
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A4.b.l Randomized Block Test
A4.b.2 Hypothesis ~est for Comparing TwoPopulation Means
A4.b.3. Hypothesis Test for Comparison of -:'an Experimental,Value to an'Ex~ctedValue
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171
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M.c.l 2.' Factorial Design
A4.c.2 2' Fa'ctorial,. Design.
M'.c.3. Dete~ination of ~ignificant Effects'\
AS SAMPLE CALCULATION OF ~LOTATION RES,ULTS .(
ALc Factorial Desig~ Analysis '174
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1'95
AS.a Determination of Maximum Vo~ume of 196Dissolved Air AVailable for'Precipitation
AS.b Determination of Solid Weight to 196Slurry Volume Ratio
AS.c Determination of Weight % Nloated 1198
AS.a Determination of % BaS04 Recovered 199
AS.e Determination of the Upgrading Factor 200
AS.f Determination oft~e %"Separation 201Efficiency
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A6 PARTICLE SIZE DETERMINATION
, A6.a Procedure
'A6.b' Particle Size Distribution
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Table
'1 Klassen.'sFlotation
LIST OF TABLES
Title,
Comparative Results ofExperiments
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2
3
4
5
6
A2-l
M-l
M-3
M-4
M-5
Klassen's Size Analysis of FlotationProducts of Barite Slimes
Random Block Analysis of the qbservedDifferences between D.A.F. andDispersed Air .Flotation
Mineral solubiiity ,Data
Comparison of Klassen's Results andCurrent 'Experimental. Obse;vations forthe Flotation of Ba~e SlimesMagnitude of Effects of FlotationVariables Relative to:D.A.F.
Equipment Specification apd Suppliers
Individual and Pooled VarianceEstimates for Each Flota~ion Parameter
Observed Differences 'between D.A.F.and Dispersed Air Flotation
Calculated T Values for the Effectof Dissolved Air Concentration on
.. .Flotation.Parameter~
Calculated T Values for the 'Difference.
'between ~.A.F. and Dispersed AirFlotation
Calculated T Values for the Effect ofCollector Concentration on FlotationParameters
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71
96
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123
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Table Title Page
A4-6' J Calculated T Values for'the Effect of lB5Depressant on Flotation Parameters
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A4-7 Calculated T Values for.Effects~oj lB6 ). Purity of BaS04 on Flotation ( .
Param~ters
I A4-B Calculated T Values for the Difference 187in Flotation Parameterll for theFlotation of gelestite and Barite fromSilica
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A4-9 Calculated Valu~s for the'Effect ofT lBB .)pH on Flotation Parameters
'A4-l0
A4-11
Calculated T,~alues for tpe Effect ofAeration (RPM) on F1otat1on Parameters
Calculatl:!d~T Values for the 'Differencebetween Klassen's Results and CurrentExperimental Observations for theFlotation of Barite Slimes
189
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E~fects of Collector Concentration,pepressant and D.A.F.
Effects of BaS04 Purity, Depressant\
and D.A.F. on Flotation Parameters
A4-12
A4-13
A4-14 Effects ofand D.A.F.
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Celes~ite Flotation, pHon'Flotation Parameters
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192.,
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A6-1
Effects of Aeration and D.A.F. onFlotation Parameters'
Particle Size Distribution
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LIST OF FIGURES
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Figure
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Title
The-Various Aspects of the SlimesProblem with Particular Reference toFlotation
Effect of Frother Concentration onthe Precipltati~n of Gases fromSolution
Effect of Saturation of the Solutionand of Frother on the Average Sizeof Gas Bubbles Precipitating fromSolution
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16
4 Total Surface Area of GasPrecipitating from 1 L ofat Different Pressures
BubblesSolution
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19
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6
7
8
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Volume of Gases Precipitating fromSolution at Different Pressures
Variation of Wl/W2 with Contact Apgle
Coalescence and Direct Attachment, . of a Bubble to a Solid Surface
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Activation of Flotation byPrecipitation of Gas Bubbles fromSolution
Flotation of a Mixture of Fluoriteand Quartz of Size less than 10 micron,
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with Different Additions of SodiumSilicate
Effect ofPUlp Density on theFlotation of a Mixture of Fluoriteand Quartz of a Size less than10 microns
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Figure Title
--Flotation of Barite and Quartzof a Size less than 10 microns withDifferent Add~tions of SodiumSilicate
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Flotation Cell and Pressure Chamber
Batch Dissolved/Dispersed AirFlota~o~ Apparatus
Distribution of Differenes in Weight% Floated between D.A.F. and DispersedAir Flotation
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50
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16
Distribution of Differences in %BaS04 Recovery between D.A.F. andDispersed Air Flotation
Differences in Upgrading Factorbetween D.A.F. and Dispersed AirFlotation
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D.A.F.17
18
Distribution of Differences inSeparation Efficiency betweenand Dispersed Air Flotation
Effect of 'Collector Concentration onthe 'Weight % Floated
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Effect of pH on % BaS04 Recovery
Effect of pH on the Upgr~ding Factor
Effect of Collector Concentration on, Separation EfficienfY
Effect of pH on weigh~ Floated
Concentration onEffect of Collector% BaS04 Recovery
81
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80
66
67
65
on
,./--,
Effect on Collector Concen~rationthe Upgrading Factor i,
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CHAPTER 1 .
INTRODUCTION
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Mineral slimes ~s a derogatory term used to indicate the
nuisance characteristics of fine mineral' particles. An acceptable
g~neral definition describes slimes as "the fraction of 'ore that is
too fine to, be commercially exploited by the conventional' processes
developed for coarser size fractions" [1].
The. upper size limit used to define slimes varies, dependinll on
the ore being treated (i.e. an upper size limit of 3 ~m for
Cassiterite [2.3] to an' upper size limit of 50 ~m for fluorite'[4]
has' been observed) and actual treatment proces~ (i.e. upper sizelimi~s for gaiena have been. industrially observed to be between 7 ~m
[5] and 20 ~m [6]).Primary slimes are, those caused, by the weathering and
decomposition of certain rock components. Secondary slimes are
produced as a result of comminution of ore.ePresently many large ore bodies are not being exploi'ted since
the liberation size of the de!l!red mineral is below 30 ~m [7];
Furthermore. often conventional mineral processes reject slimes whichmay contain an appreciable mineral content because of treatment
difficulties.
However. with the continued exhaustion of natural reso,urces it
is important that problems in recovering slimes be resolved.
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McMaster UniversityDigitalCommons@McMaster3-1-1982
Evaluation of Dissolved Air Flotation for the Treatment of Mineral SlimesAlan Jospeh MelnykRecommended Citation