Predicting HCN gas generation in the SART process

Estay, Humberto; Becker, J.; Carvajal, Pablo; Arriagada, Francisco

doi:10.1016/j.hydromet.2011.12.019

Cited by 15 publications

(11 citation statements)

References 8 publications

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“…Even then, the cyanide that deports to Fe(CN) 6 4 − and thiocyanate cannot be economically recovered (Dai et al, 2012;Estay et al, 2012). (4) The presence of copper in the final tail solutions significantly contributes to weak acid dissociable (WAD) cyanide species which should be kept below 50 mg/L before the tail water is discharged to the environment (Botz and di Parodi, 1997;Donato et al, 2007;Mudder and Botz, 2001) and, consequently, requires additional cyanide detoxification/destruction processes.…”

Section: Introductionmentioning

confidence: 99%

Gold leaching in cyanide-starved copper solutions in the presence of glycine

Oraby

Eksteen

2015

Hydrometallurgy

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Section: Introductionmentioning

confidence: 99%

Gold leaching in cyanide-starved copper solutions in the presence of glycine

Oraby

Eksteen

2015

Hydrometallurgy

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“…The volatilization of HCN would also cause a significant loss of the effective cyanide concentration in the experimental system. The equilibrium behavior of such process at liquid‐gas interface is typically described in Henry′s law for HCN (Equation (2)) 20 …”

Section: Experimental Methodsmentioning

confidence: 99%

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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“…The most common recovery techniques for cyanides from mining effluents are acidification–volatilization–reneutralization process and the sulphidization–acidification–recycle–thickening. Other processes implemented at industrial scale and reported in the literature are Cyanisorb, Metallgeseltshaft Natural Resources process and Biosulphide . Potential processes are ion exchange resins, biosorption and membranes.…”

Section: Cyanide Tailingsmentioning

confidence: 99%

Purification techniques for the recovery of valuable compounds from acid mine drainage and cyanide tailings: application of green engineering principles

García

Häyrynen

Landaburu-Aguirre

et al. 2014

J of Chemical Tech & Biotech

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The metal mining of certain minerals is associated with the generation of acid mine drainage waters and effluents containing cyanides that can have long-term negative impacts on waterways and biodiversity. Obtaining valuable components from those effluents would improve the resource efficiency and the environmental performance of mining. This paper reviews the main separation processes cited in literature for the purification of real acid mine drainage waters and cyanide tailings, and for the recovery of heavy metals and cyanides from those effluents. The processes used are adsorption and membrane technology to obtain valuable compounds from acid mine drainage waters and ion-exchange, acidification-volatilization-reneutralization, sulphidization-acidification-recycling-thickening and membrane technology from cyanide tailings. Further, the use of the 12 green engineering principles for improving the environmental performance of the purification techniques is debated. This work indicates that the energy and chemical consumption and the formation of waste are the main environmental disadvantages of the purification and recovery techniques. This paper concludes that the limitations may be overcome by improving the efficiency of the processes and by using renewable energy and material. The benefits of conducting the purification and recovery techniques utilizing hybrid processes are also pointed out.

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Predicting HCN gas generation in the SART process

Cited by 15 publications

References 8 publications

Gold leaching in cyanide-starved copper solutions in the presence of glycine

Gold leaching in cyanide-starved copper solutions in the presence of glycine

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

Purification techniques for the recovery of valuable compounds from acid mine drainage and cyanide tailings: application of green engineering principles

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