Gold losses by cementation and thermal reduction in the gold recovery circuits

In this study, gold losses in a carbon-in-pulp (CIP) cyanidation gold recovery process and potential sources of these losses were investigated. Gold was found in samples from different streams through the CIP-cyanidation process, pointing to incidental losses. Mineralogical studies showed that gold losses occurred in two main forms, either as attached to larger entities or in the form of dendritic precipitates. SEM and EDS studies revealed that iron bearing minerals acted as the major media in cases when gold associations were observed as losses. The highly alkaline pH (approximate to 13), elevated process temperature (approximate to 145 degrees C), and high cyanide concentration (>= 250 ppm) in the elution column along with a fine iron bearing material implied that gold attachment occurred through an electrochemical cementation mechanism. It was anticipated that the presence of iron in the process, which facilitated gold cementation, relied on the oxidative breakdown of the iron bearing minerals in the ore and/or due to the formation of porous iron oxides due to the roasting of iron sulfides in the regeneration kiln. In the elution column some part of the auro-cyanide complexes would remain non-eluted and be discharged into the carbon generation kiln and the carbon generation kiln was another section promoting gold losses. The high temperature condition in the carbon regeneration kiln (>500 degrees C) caused thermal reduction of the non-eluted auto-cyanide complexes to metallic gold, leading to the formation of dendritic gold precipitates and their eventual loss.


Estimation of Hardgrove grindability index of Turkish coals by neural networks
Ozbayoglu, Gulhan; ÖZBAYOĞLU, AHMET MURAT; Ozbayoglu, M. Evren (Elsevier BV, 2008-01-31)
In this research, different techniques for the estimation of coal HGI values are studied. Data from 163 sub-bituminous coals from Turkey are used by featuring I I coal parameters, which include proximate analysis, group maceral analysis and rank. Nonlinear regression and neural network techniques are used for predicting the HGI values for the specified coal parameters. Results indicate that a hybrid network which is a combination of 4 separate neural networks gave the most accurate HGI prediction and all of...
Extraction of cobalt and copper from Küre pyrite concentrate
Çokgör, O.; Topkaya, Yavuz Ali (Elsevier BV, 1988)
Three methods were investigated for the extraction of cobalt, copper and gold from Kure pyrite concentrate. These were chloridizing roasting, chloridizing volatilization and sulphating roasting processes. For chloridizing roasting, the pyrite concentrate was dead roasted first to adjust sulfur content to about 4%. Then, the pyrite cinder obtained was mixed with NaCl and pyrite concentrate, and roasted to produce soluble chlorides of copper and cobalt. For chloridizing volatilization, copper, cobalt and g...
Assessment of the collapse mechanisms of tufa deposits
Dipova, N; Doyuran, V (Elsevier BV, 2006-03-03)
This research assesses the collapse mechanisms of tufa deposits. The city of Antalya, located on the Mediterranean coast of Turkey, has been settled on tufa deposits. By the end of 1980s, the area behind the tufa cliffs became the site of high-rise residential buildings. Some of these buildings have suffered from foundation instabilities, which have given rise to cracking and fissuring of the walls, and overall tilting. The collapsible behaviour upon loading and/or wetting of some tufa deposits has caused f...
Enhancement of flotation performance of oil shale cleaning by ultrasonic treatment
Altun, Naci Emre; Hicyilmaz, Cahit (Elsevier BV, 2009-04-16)
In this study, it was attempted to enhance the performance of flotation cleaning of oil shales by use of ultrasound. The use of an excitation effect through ultrasonication was investigated towards inorganic particles that remain clogged in pores/voids or attached as surface coatings. Ultrasonic treatment was applied prior to flotation at different ultrasonic power levels and for different ultrasonication periods. Ultrasonic treatment proved to be useful in improving the extent of ash rejection. After ultra...
Hydrometallurgical processing of nontronite type lateritic nickel ores by MHP process
Kose, C. H.; Topkaya, Yavuz Ali (Elsevier BV, 2011-04-01)
The research work presented in this paper determined the optimum conditions at which nickel and cobalt could be obtained at maximum efficiency from the column leach liquor of the lateritic nickel ore existing in Gordes region of Manisa in Turkey by performing effective hydrometallurgical methods. This column leach solution was initially neutralized and purified from its basic impurities by a two-stage iron removal process, nickel and cobalt were precipitated in the form of mixed hydroxide precipitate from t...
Citation Formats
B. Klein and N. E. Altun, “Gold losses by cementation and thermal reduction in the gold recovery circuits,” INTERNATIONAL JOURNAL OF MINERAL PROCESSING, pp. 24–29, 2011, Accessed: 00, 2020. [Online]. Available: