Application of eMAX analysis of pressure oxidation of refractory gold ores

Jukka Laukkanen, Jaakko Leppinen

Research output: Contribution to journalArticleScientificpeer-review

2 Citations (Scopus)

Abstract

A SEM-EDS based image analysis method (eMAX) was applied for quantitative determination of the solid composition in pressure oxidation tests of a complex refratory gold ore. The decomposition of sulphides and the formation of secondary phases were calculated on the basis of the image analysis data. The ore examined contained over 60% of its gold as “invisible gold” occurring predominantly in an iron arsenide mineral loellingite (FeAs2), while the other sulphides containe pratically no gold. Therefore, the pressure oxidation test scheme was focused on evaluating the possibilities of selective oxidation of loellingite. eMAX analysis was very useful in determining the amounts of pyrite, pyrrhotite, arsenopyrite, loellingite, and galena as well as the decomposition productes such as ferric arsenate, iron hydroxy sulphate, and hematite. At 180°C, 11 bar oxygen, 96% of the loellingite decomposed in 30 minutes compared with less than 60% of the pyrite and 78% of the total phase. At 210°C the oxidation selectivity between loellingite and other sulphides was poor. The cynidation tests showed that a gold recovery of over 90% was achieved after 30 min autoclaving. The selective oxidation would yield cost savings as reduced oxugen consumption and also result in lower neutralization costs and less low-density waste material.
Original languageEnglish
Pages (from-to)239-249
Number of pages11
JournalMinerals Engineering
Volume7
Issue number2-3
DOIs
Publication statusPublished - 1994
MoE publication typeA1 Journal article-refereed

Fingerprint

Gold
Refractory materials
Ores
gold
oxidation
Sulfides
Oxidation
Pyrites
sulfide
image analysis
Image analysis
pyrite
Iron
decomposition
Decomposition
iron
arsenopyrite
Hematite
arsenate
neutralization

Cite this

Laukkanen, Jukka ; Leppinen, Jaakko. / Application of eMAX analysis of pressure oxidation of refractory gold ores. In: Minerals Engineering. 1994 ; Vol. 7, No. 2-3. pp. 239-249.
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title = "Application of eMAX analysis of pressure oxidation of refractory gold ores",
abstract = "A SEM-EDS based image analysis method (eMAX) was applied for quantitative determination of the solid composition in pressure oxidation tests of a complex refratory gold ore. The decomposition of sulphides and the formation of secondary phases were calculated on the basis of the image analysis data. The ore examined contained over 60{\%} of its gold as “invisible gold” occurring predominantly in an iron arsenide mineral loellingite (FeAs2), while the other sulphides containe pratically no gold. Therefore, the pressure oxidation test scheme was focused on evaluating the possibilities of selective oxidation of loellingite. eMAX analysis was very useful in determining the amounts of pyrite, pyrrhotite, arsenopyrite, loellingite, and galena as well as the decomposition productes such as ferric arsenate, iron hydroxy sulphate, and hematite. At 180°C, 11 bar oxygen, 96{\%} of the loellingite decomposed in 30 minutes compared with less than 60{\%} of the pyrite and 78{\%} of the total phase. At 210°C the oxidation selectivity between loellingite and other sulphides was poor. The cynidation tests showed that a gold recovery of over 90{\%} was achieved after 30 min autoclaving. The selective oxidation would yield cost savings as reduced oxugen consumption and also result in lower neutralization costs and less low-density waste material.",
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Application of eMAX analysis of pressure oxidation of refractory gold ores. / Laukkanen, Jukka; Leppinen, Jaakko.

In: Minerals Engineering, Vol. 7, No. 2-3, 1994, p. 239-249.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Application of eMAX analysis of pressure oxidation of refractory gold ores

AU - Laukkanen, Jukka

AU - Leppinen, Jaakko

N1 - Project code: MIN1019

PY - 1994

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N2 - A SEM-EDS based image analysis method (eMAX) was applied for quantitative determination of the solid composition in pressure oxidation tests of a complex refratory gold ore. The decomposition of sulphides and the formation of secondary phases were calculated on the basis of the image analysis data. The ore examined contained over 60% of its gold as “invisible gold” occurring predominantly in an iron arsenide mineral loellingite (FeAs2), while the other sulphides containe pratically no gold. Therefore, the pressure oxidation test scheme was focused on evaluating the possibilities of selective oxidation of loellingite. eMAX analysis was very useful in determining the amounts of pyrite, pyrrhotite, arsenopyrite, loellingite, and galena as well as the decomposition productes such as ferric arsenate, iron hydroxy sulphate, and hematite. At 180°C, 11 bar oxygen, 96% of the loellingite decomposed in 30 minutes compared with less than 60% of the pyrite and 78% of the total phase. At 210°C the oxidation selectivity between loellingite and other sulphides was poor. The cynidation tests showed that a gold recovery of over 90% was achieved after 30 min autoclaving. The selective oxidation would yield cost savings as reduced oxugen consumption and also result in lower neutralization costs and less low-density waste material.

AB - A SEM-EDS based image analysis method (eMAX) was applied for quantitative determination of the solid composition in pressure oxidation tests of a complex refratory gold ore. The decomposition of sulphides and the formation of secondary phases were calculated on the basis of the image analysis data. The ore examined contained over 60% of its gold as “invisible gold” occurring predominantly in an iron arsenide mineral loellingite (FeAs2), while the other sulphides containe pratically no gold. Therefore, the pressure oxidation test scheme was focused on evaluating the possibilities of selective oxidation of loellingite. eMAX analysis was very useful in determining the amounts of pyrite, pyrrhotite, arsenopyrite, loellingite, and galena as well as the decomposition productes such as ferric arsenate, iron hydroxy sulphate, and hematite. At 180°C, 11 bar oxygen, 96% of the loellingite decomposed in 30 minutes compared with less than 60% of the pyrite and 78% of the total phase. At 210°C the oxidation selectivity between loellingite and other sulphides was poor. The cynidation tests showed that a gold recovery of over 90% was achieved after 30 min autoclaving. The selective oxidation would yield cost savings as reduced oxugen consumption and also result in lower neutralization costs and less low-density waste material.

U2 - 10.1016/0892-6875(94)90067-1

DO - 10.1016/0892-6875(94)90067-1

M3 - Article

VL - 7

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