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Cyanide-less Gold Extracting from Refractory Ores


Ecologically Safe Technology of Cyanide-less Gold Extraction from Concentrates of Refractory Gold Containing Sulfide Ores and Tailing Dumps

Tech Area / Field

  • CHE-IND/Industrial Chemistry and Chemical Process Engineering/Chemistry
  • ENV-APC/Air Pollution and Control/Environment

3 Approved without Funding

Registration date

Leading Institute
Kyrgyz National Technical University / Chemical Technological Scientific Research Institute, Kyrgyzstan, Bishkek


  • Geoexplorers International, Inc, USA, CO, Denver\nCenter for Russian and Central Asian Mineral Studies, UK, London\nNatural Resources Canada / Mining and Mineral Sciences Laboratories, Canada, ON, Ottawa

Project summary

The Goals of the Project.

1. Elaboration of the perspective Ecologically Safe Complex technology of cyanide free Gold Extraction from Concentrates of refractory gold containing ores, Tailing Dumps (industrial level).

2. Composition of the Technological Scheme, creation, constructing and mounting of Pilot Line for Cyanide free Gold Extraction from Concentrates of refractory ores, line which will be adapted to functioning production of Gold and Antimony; (Kadamjai antimony combinat, Kyrgyz Republic).

3. Approbation (industrial tests) of designed technology, and an estimation of its ecological safety and economic efficiency. Recommendation on this technology introduction.The main purpose of the project is to create ecologically safe cyanide free technology, to increase the raw material gold base, utilization of tailing dumps, and improvement of ecological situation in the processing regions.

The Actuality of the Project is defined by exhaustion of deposits of mono metallic and simple gold-containing ores. The part of the gold extracted from the simple (from the technological point of view) ores, for which it is possible to use the standard scheme, decreases steadily. At the same time, the part of the gold extracted from the refractory gold-containing ores, increases. That is why, for the gold production it is necessary to involve the raw materials such as: Refractory Ores and Rocks with low content of Gold, which are hard-to-process. The Refractory Gold Containing Sulfide Ores are characterized by complex structure, by extremely thin impregnation of gold in sulfide ores (so called fine-particle gold with particle size from 1 to 5 micrometer), and by the presence of components, which decrease the extraction of gold under cyanidation. Using existent technologies (Cyanide Technique and etc.) don’t give high level of Gold Extraction; also demand higher expenses for its using and ecologically safeness.

Under these conditions it is necessary to find out Rational and Ecologically Safe Technologies of Gold Extraction from Refractory Materials (Concentrates of Gold Containing Sulfide Ores, and Tailing Dumps), to develop technologies, allowing to increase the base of raw material source for involving in processing first of all Refractory Ores, and Gold Containing Rocks with low content of Gold in Rock, utilization of Blade of operational fields, Tailing Dumps. This Tendency is typical not only for the Kyrgyz Republic, but also for the World Gold Industry as a whole.

In the base of the elaborated technology there is the improved by the authors of the Project the Thiocarbamide “TC”-technology of Gold Extraction from Refractory Gold-Containing raw materials. Elaborated technology has several advantages and improvements, which will give an opportunity to apply it in industry. Technology is characterized by the usage of ecologically more safe reagents, optimal and effective ratio of reagents mass. The conditions of minimal thiourea dissolution under the high gold extracting degree are established; optimal size of sour- rehabilitation potential of process is identified. The problem of large free gold extraction at the process starting stage by means of gravitational apparatus (in order to prevent depression of flotation) is at the stage of decision.

In order to achieve the mentioned purposes, the pre-project KR-877 “Feasibility Study” was carried out during 9 months. Achieved results are; Working Plan to the KR-877 Project (Laboratory level); an economic efficiency calculations of flotoconcentrate processing of Terekan deposit gold bearing ores using “TC” thiocarbamide technology, profitability according to “TC”-technology equals to 26.03%; An agreement of the “Kadamjai antimony combinat” directorate on free-of charge producing area grant and reinting the existing equipment for assembling of the pilot line for gold recovery according to the authors’ “TC” technology was achieved. The permission to conduct the production tests using the given pilot line on gold extraction from 10 tons of concentrate was received.

The results of the pre-Project KR-877 were presentented in: 3 published papers, 6 reports on the conferences, and 2 patents

Project will be fulfilled by the Scientific Chemical Technological Institute of Kyrgyz Technical National University named after I.Razzakov.

The workers of the Project appreciates the financing side for the given possibility to obtain the presented results and express their thanks to the Project collaborators Dr. Reimar Seltmann ( UK ) и Dr. Jan Krason (USA) for their support and valuable help during the project work.


The International Science and Technology Center (ISTC) is an intergovernmental organization connecting scientists from Kazakhstan, Armenia, Tajikistan, Kyrgyzstan, and Georgia with their peers and research organizations in the EU, Japan, Republic of Korea, Norway and the United States.


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