CONCENTRATEDEECTROLYTESIN MINERALPROCESSINGCIRTUITSJanuszS.LaskowskiNB Keevil Institute of Mining EngineeringUniversity of British ColumbiaNORMANB.KEEVILINSTITUTE OFMINING ENGINEERINGwww.mining.ubc.ca
Janusz S. Laskowski NB Keevil Institute of Mining Engineering University of British Columbia CONCENTRATED EECTROLYTES IN MINERAL PROCESSING CIRTUITS
The results discussed in this presentation are takenfrom many publications as acknowledged in eachcase.The data on the use of seawater in flotation ofCu-Mo sulfide ores resulted from the AMIRA ProjectFlotacion de Minerales de Cobrein Aguas Salinascarried out at the University of Concepcion, ChileThese results have been discussed in several jointpublications with Professor Sergio Castro,Department of Metallurgical Engineering,UniversityofConcepcion,Chile.NORMAN B.KEEVILINSTITUTE OF MINING ENGINEERINGwww.mining.ubc.ca
The results discussed in this presentation are taken from many publications as acknowledged in each case. The data on the use of seawater in flotation of Cu-Mo sulfide ores resulted from the AMIRA Project “Flotación de Minerales de Cobre in Aguas Salinas” carried out at the University of Concepcion, Chile. These results have been discussed in several joint publications with Professor Sergio Castro, Department of Metallurgical Engineering, University of Concepción, Chile
COMMINUTIONCONCENTRATIONWATERCLARIFICATIONPRODUCTDEWATERINGNORMAN B.KEEVILINSTITUTE OF MINING ENGINEERINGwww.mining.ubc.ca
For the sake of discussion the systems in which flotation iscarried out in concentrated electrolytes will be categorized intothreegroups:(i)The group exemplified by salt flotation of inherentlyhydrophobic solids (example:flotationof bituminous coalinNaCl solution);(ii)The group in which flotationis depressed as collectorprecipitates with some ions which are constituents of theelectrolyte system (example:theuse offattyacids inflotationinhardwater/seawater);(ii) Cu-Mo sulfideore flotationin seawater;in this case somevaluable ore constituents are depressed by precipitatingproducts of hydrolysing cations.NORMAN B.KEEVILINSTITUTE OF MINING ENGINEERINGwww.mining.ubc.ca
For the sake of discussion the systems in which flotation is carried out in concentrated electrolytes will be categorized into three groups: (i) The group exemplified by salt flotation of inherently hydrophobic solids (example: flotation of bituminous coal in NaCl solution); (ii) The group in which flotation is depressed as collector precipitates with some ions which are constituents of the electrolyte system (example: the use of fatty acids in flotation in hard water/seawater); (iii) Cu-Mo sulfide ore flotation in seawater; in this case some valuable ore constituents are depressed by precipitating products of hydrolysing cations
Flotationofinherentlyhydrophobicmineralsinconcentrated solutionsofelectrolytes does not reguire the use ofcollectors.In Klassen's publications thisisreferred to as"salt flotation."(KlassenandMokrousow,An IntroductiontotheTheoryofFlotation,Butterworths,London,1963).Sinceinorganicionscannot change wettability of solidsurfaces only inherently hydrophobicsolids can float under such conditions.NORMANB.KEEVILINSTITUTE OF MINING ENGINEERINGwww.mining.ubc.ca
Flotation of inherently hydrophobic minerals in concentrated solutions of electrolytes does not require the use of collectors. In Klassen’s publications this is referred to as “salt flotation.” (Klassen and Mokrousow, An Introduction to the Theory of Flotation, Butterworths, London, 1963). Since inorganic ions cannot change wettability of solid surfaces only inherently hydrophobic solids can float under such conditions
Metallurg3080coalsWater-Sessile0Drops250200(%) xo4Water-Captive15Bubble0A10Oxygen20A510A0065707580859095100Carbon(%,daf)Coal wettabilityNORMAN B.KEEVILINSTITUTE OF MINING ENGINEERINGwww.mining.ubc.ca
Metallurg. coals Coal wettability
0.8I-NIXN0.6OR0.4E0.2RH02001030MOISTURE(ASRECEIVED),%Effectof coalsurfacewettability(expressedbycoalinherentmoisturecontent)onthesaltflotationrate(inO.5MNaCl)(Fuerstenau,RosenbaumandLaskowski,Coll.&Surf.,1983)NORMAN B.KEEVILINSTITUTE OF MINING ENGINEERINGwww.mininq.ubc.ca
0 10 20 30 MOISTURE (AS RECEIVED), % 0 0.2 0.4 0.6 0.8 1 MAXIMUM k, min -1 F J K E D H B A C Effect of coal surface wettability (expressed by coal inherent moisture content) on the salt flotation rate (in 0.5 M NaCl) (Fuerstenau, Rosenbaum and Laskowski, Coll.&Surf., 1983)
The subiectof thesalt flotation has beenrecently returning to research labs sincemining industry -in many parts of theworld-isfacing very severeshortages ofwater.And the use of seawater,theconcentrated electrolyte solution,becomes the onlysustainablesolutionPerhapsthe bestexampleofalargearidarea with very limited fresh waterresources and a huge mining industry isAtacamaDesertinChile.NORMAN B.KEEVILINSTITUTE OF MINING ENGINEERINGwww.mining.ubc.ca
The subject of the salt flotation has been recently returning to research labs since mining industry - in many parts of the world - is facing very severe shortages of water. And the use of seawater, the concentrated electrolyte solution, becomes the only sustainable solution. Perhaps the best example of a large arid area with very limited fresh water resources and a huge mining industry is Atacama Desert in Chile
Anionicflotation with fatty acids:- at high concentration of Ca/Mgionsinthepulp;inseawaterNORMAN B.KEEVILINSTITUTE OF MINING ENGINEERINGwww.mining.ubc.ca
Anionic flotation with fatty acids: - at high concentration of Ca/Mg ions in the pulp; - in seawater
KapuskasingPhosphateOperations(KPO)inOntario,whichbelongstoAgrium Inc.,is the only Canadianphosphate mine.While the ore from theircurrent operation is relatively easy toupgrade byflotation,the marginal ore,which was stockpiledatthe site forabouttwo years turned out to be extremelydifficultto process.The process waterwasfoundto containmore than 1oooppmCa2+.NORMAN B.KEEVILINSTITUTE OF MINING ENGINEERINGwww.mining.ubc.ca
Kapuskasing Phosphate Operations (KPO) in Ontario, which belongs to Agrium Inc., is the only Canadian phosphate mine. While the ore from their current operation is relatively easy to upgrade by flotation, the marginal ore, which was stockpiled at the site for about two years turned out to be extremely difficult to process. The process water was found to contain more than 1000 ppm Ca2+