FTIR and flotation investigation of the adsorption of ethyl xanthate on activated and non-activated sulfide minerals

Leppinen, Jaakko

doi:10.1016/0301-7516(90)90018-t

Cited by 191 publications

(73 citation statements)

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“…However, a high pyrite flotation recovery can be achieved at a pH value of 4 to 5 (Leppinen 1990, Zhang et al 1997. Generally, the dependency of mineral floatability on pH is due to the different surface species formed at different pH values which not only influence the mineral surface hydrophobicity but also affect the collector adsorption (Cases et al 1993).…”

Section: Effect Of Grinding Ph On Flotationmentioning

confidence: 99%

“…Laajalehto et al (1999) demonstrated that the new phase on the copper activated pyrite was probably a chalcopyrite type (CuFeS2), and the reduction of Cu 2+ was compensated by the oxidation of iron when chalcopyrite was formed. proposed (Leppinen 1990, Buckley 1994, Valdivieso et al 2005. However, the adsorption of collector on un-activated pyrite surface is minimal at alkaline conditions.…”

Section: Pyrite Activation Mechanism By Copper Ionsmentioning

confidence: 99%

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The effect of regrinding chemistry and particle breakage mechanisms on subsequent cleaner flotation

Chen¹

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Regrinding rougher flotation concentrates is typically used to liberate valuable minerals from gangue prior to the cleaner separation stage in processing of low grade ores. Compared to the rougher flotation after primary grinding, it is usually more challenging to achieve a satisfactory performance in post-regrind cleaner flotation especially when fine particles are generated. One main factor which results in this reduction in flotation is the unsuitable particle surfaces produced after regrinding. However, this factor is not usually considered when designing and optimizing the regrinding process.Extensive studies have demonstrated that grinding chemistry can influence mineral floatability.However, earlier studies focused on primary grinding and rougher flotation rather than regrinding and cleaner flotation. In addition, different types of regrind mills are used in industry, and these provide different particle breakage mechanisms which may also influence mineral floatability.Therefore, the overall objective of this thesis study is to investigate the effects of regrinding chemistry and particle breakage mechanisms on the cleaner flotation. The implementation of regrinding in the copper and pyrite flotation circuits at Telfer gold mine was taken as a case study and four research areas were addressed with the objective of developing fundamental understanding to provide practical guidance for the plant operation. The four areas investigated are:1. Effect of regrinding chemistry on copper activation of pyrite and its flotation; 2. Separation of different copper sulphide minerals from pyrite after regrinding; 3. Importance of pulp chemistry during regrinding rougher concentrates; 4. Effect of particle breakage mechanisms on subsequent flotation.In this study, it was found that copper activation of pyrite and its flotation in the cleaner stage were affected by regrinding. In general, a decrease in surface concentration of collectors due to the increased surface area after regrinding contributed to the low pyrite recovery in the cleaner. Surface analysis revealed that both the surfaces that were carried from the rougher flotation concentrate and those which were freshly created were modified by the strong electrochemical reactions occurring inside the regrind mill. Stainless steel media promoted pyrite oxidation, especially on the copper activated surfaces. Mild steel media produced a greater amount of iron oxidation species which could adsorb on the carried surfaces. It was also found that mild steel media generated a reducing condition which favoured the copper activation on the freshly created surfaces.ii The research has also shown that the separability of chalcopyrite and chalcocite from pyrite was significantly different after regrinding, which was related to their electrochemical properties.Chalcocite was more active and therefore presented a stronger galvanic interaction with pyrite.Consequently chalcocite was more oxidised, which not only depressed its flotation but also produced sufficient copper ions...

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Section: Effect Of Grinding Ph On Flotationmentioning

confidence: 99%

Section: Pyrite Activation Mechanism By Copper Ionsmentioning

confidence: 99%

The effect of regrinding chemistry and particle breakage mechanisms on subsequent cleaner flotation

Chen¹

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“…It has been accepted that Cu(I)-xanthate is the major surface species responsible for hydrophobicity of Cu-activated sphalerite (Leppinen, 1990;Mielczarski et al, 1989;Mikhlin et al, 2016b;Pattrick et al, 1999;Popov and Vucinic, 1990b;Porento and Hirva, 2005;Prestidge et al, 1994;Terms and Richardston, 1986;). …”

Section: Collector Adsorptionmentioning

confidence: 99%

“…However, dixanthogen adsorption is more prevalent on un-activated sphalerite or when the Cu(II) concentration is low (Leppinen, 1990). It has also been proposed that the Chapter 2: Literature review 28 formation of dixanthogen only occurs through precipitation from solution when excess Cu(II) ions are present .…”

Section: Collector Adsorptionmentioning

confidence: 99%

“…The similar reaction could happen between Fe(OH) 2(surface) and X -ions in pyrite flotation using thiol collectors (Fornasiero and Ralston, 1992). However, the available literature (Fornasiero and Ralston, 1992;Leppinen, 1990;Mikhlin et al, 2016a;Wang and Forssberg, 1991) proposes that the dixanthogen would be the main surface product of the interaction of xanthate with pyrite.…”

Section: Introductionmentioning

confidence: 99%

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Bubble attachment and Amyl Xanthate adsorption to copper-activated sphalerite

Ejtemaei¹

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Sphalerite (ZnS) is a primary source of zinc metal. It usually coexists with other sulphide minerals such as pyrite (FeS 2 ) and galena (PbS). Its concentration is accomplished by froth flotation using short-chain thiol collectors such as xanthate. Due to its unique chemical and structural characteristics, the concentration of sphalerite by flotation requires Cu-activation, which is a process of making the mineral susceptible to reactions with the thiol collectors. The high amount of copper sulphate consumption is a big challenge for zinc processing plants, and the parameters that lead to a significant amount of copper sulphate usage for sphalerite activation is not wellunderstood. Based on the literature review and zinc processing plants reports, process water quality and the presence of pyrite during sphalerite Cu-activation could be two main factors affecting the activation that are the main focus of this thesis.To develop insight into mechanisms of Cu-activation of sphalerite and pyrite, Cryogenic X-ray Photoelectron Spectroscopic (Cryo-XPS) and zeta potential measurements were applied. The Cryo-XPS results showed that Cu-activation of sphalerite was an ion exchange reaction with CuS-type layer formation, while pyrite Cu-activation was governed by redox reactions with CuFeS 2 -type layer development. Depth profiling after 10 min activation revealed Cu diffusion into the sphalerite lattice up to 10 nm, while the thickness of the activation product on pyrite surface was less than 3 nm. The zeta potential studies confirmed proposed surface products on the minerals by Cryo-XPS.Hydrophobicity and many other surface properties of Cu-activated sphalerite can be changed by dissolved ions available in the process water (e.g. calcium, magnesium and sulphate). The effect of Ca(NO 3 ) 2 , Mg(NO 3 ) 2 , MgSO 4 and CaSO 4 on the surface properties of Cu-activated sphalerite was studied using sessile drop Contact Angle (CA), Cryo-XPS and zeta potential measurements. The CA measurements showed that the hydrophobicity of sphalerite developed after Cu-activation, but the presence of 3×10 -2 M Ca(NO 3 ) 2 or Mg(NO 3 ) 2 or MgSO 4 decreased its hydrophobicity. The XPS data showed that the effect of these ions appeared to be the same, namely a decrease in Cu adsorption and polysulphide formation. Zeta potential measurements confirmed the presence of calcium and magnesium ions on the sphalerite surface.Sphalerite is not the only sulphide mineral whose flotation behaviour can be affected by the presence of Cu ions in solution. The possibility of inadvertent Cu-activation of pyrite and its undesirable flotation is one factor accounting for the effective separation of sphalerite from pyrite.The surface hydrophobicity and components of the Cu-activated sphalerite were measured to investigate Cu adsorption kinetics of sphalerite in the presence of pyrite using a novel experimental approach of High-Speed Video Microscopy (HSVM) and Cryo-XPS. HSVM method allowed for ii in-situ liquid film Drainage rate (DR) and bubble-mineral CA...

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The Poisoning of Pyrite Surface upon Xanthate Adsorption by Cyanide in Mildly Acidic Media

Guo

2015

Electroanalysis

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[a] 1Introduction Thea dsorption of organic species ontom inerala tt he solid-liquid interface is of significance for the establishmento fh ydrophobics urface,r enderingm inerals flotation possible.I ti sn ow well established thatt he interaction of typicalc ollector xanthate withp yrite, the most abundant sulfide minerals is electrochemicali nn ature [ 1].T he pyrite-xanthatei nteraction is affected by manyf actors sucha spH, redox potential,a nd differents olution species, in addition to the history of the mineral. It was reported [2-4] thatt he maximum flotationr ecoveryo fp yritei so bserveda tm ildly acidicp H( 3.5-5.5),e specially withl ow xanthate concentration. Thed epression at lower pH has been attributed to the decomposition of xanthatei ons [ 4]. Thec hemisorption of xanthatep resumably involves the oxidation of xanthatet od ixanthogeno np yrite [4][5][6][7][8]. Spectroscopics tudies [ 8] showt hatt he amount of adsorbed xanthater eaches am aximuma tp H5 after treatmentw ith1 0 À4 xanthate solution andd ecreases steadily withf urtheri ncreasingp H. Theg reater extent of hydrophilic ferric hydroxidecoverage on pyritewith the increasingpHisunfavorable for the adsorptionofxanthate [4,7]. Thepoorfloatabilityinneutral media hasalsobeenattributedt ot he formation of hydrophilicf erric dihydroxyx anthate,F e(OH) 2 EX, over apHrange from5to 9 [2,3].It was also revealed that cyanide inhibited all surface electrochemical activities, rendering pyrite surface hydrophilic [9][10][11][12][13][14].C yanide speciation largelyd epends on pH of the solution. Thec yanide anion in aqueous solution forms hydrocyanic acid (HCN)a ccording to the dissociation reaction in Equation (1) [15].Thel ogarithmic exponent of the dissociation constant pKa of HCN at 25 8Cis9 .21 [16].ApH value higher than 9.21 increases CN À concentration while ap Hvalue lower than 9.21 promotes the presence of aqueous HCN in the solution.C yanide consistently exists as HCN whenp Hi s lower than 7 [ 16].T hough numerous studies of this system were carried out, the depression mechanism of cyanide has been controversial and was postulated to be associated with the formation of iron-cyanide compounds on pyrite surface [17,18] or the inhibitiono fx anthate oxidation at reducingp otential in the presenceo fc yanide [13,19].F urthermore,t hose studies involving cyanidepyrite interaction were conducted at neutralt oa lkaline pH. Thex anthate chemisorption in the presenceo fH CN in mildly acidic media is unknown, whichi s, however, of great importance whent he maximum recovery of pyrite is desired in flotation, particularly for auriferous pyritic ore.Due to the maximum xanthate chemisorptiono np yrite can be achieved at pH 5[ 8],t he impact of HCN on pyrite-xanthate interaction was investigated at pH 5b y means of electrochemical measurements. 2Experimental MethodsAh and-picked naturalm assive cubic pyrite specimen originated fromS pain was used as workinge lectrode.X -ray fluorescence (XRF) analysis shows that the pyrite specimen had as ulfurc ontento f6 ...

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FTIR and flotation investigation of the adsorption of ethyl xanthate on activated and non-activated sulfide minerals

Cited by 191 publications

References 7 publications

The effect of regrinding chemistry and particle breakage mechanisms on subsequent cleaner flotation

The effect of regrinding chemistry and particle breakage mechanisms on subsequent cleaner flotation

Bubble attachment and Amyl Xanthate adsorption to copper-activated sphalerite

The Poisoning of Pyrite Surface upon Xanthate Adsorption by Cyanide in Mildly Acidic Media

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