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Processing of persistent ores

#T-2035


Ecologically pure new technologies of persistent arsenic-containing gold ores processing

Tech Area / Field

  • BIO-IND/Industrial Biotechnology/Biotechnology
  • CHE-IND/Industrial Chemistry and Chemical Process Engineering/Chemistry
  • ENV-EHS/Environmental Health and Safety/Environment
  • OBS-NAT/Natural Resources and Earth Sciences/Other Basic Sciences

Status
3 Approved without Funding

Registration date
17.09.2012

Leading Institute
Institute of Chemistry named after V.I.Nikitin, Academy of Sciences, Republic of Tajikistan, Tajikistan, Dushanbe

Collaborators

  • National Research Council, Italy, Rome

Project summary

The aim of this project is fundamental study of the material composition of gold-containing ores of Tajikistan and the identification of submicroscopic gold, the selection of the consortium microorganisms composition for the opening and the sorption of natural nano-sized particles of gold, the researches of flowsheets to produce gold-containing concentrates with the subsequent processing by biotechnology. Study sorption of gold bybiomass from pulp, carrying flotation and obtaining of nanosized gold particles after decomposition of biomass, rich in gold. Removal the toxic metals from sewages by nanosorbents.
Status of researches. The Republic of Tajikistan has considerable mineral resources, including gold ore, which, by their mineral composition are classified as rebellious ores, and that in the short term will be processed. One feature of the mineralogical composition of rebellious gold ores is the presence in it of nanosized particles of gold. This is submicroscopic gold with the sizes 1-100 nм (" invisible gold "). Usually such gold occurs in pyrite, arsenopyrite, marcasite. In practice of such ores enrichment for the opening of finely dispersed gold is applied oxidizing roasting, or nitric acid leaching followed by cyanidation leach residues, or cinders. These technologies are unsafe for the environment, because cyanide is used to strongly toxic compounds. In many plants using cyanide, which detected high amounts of cyanide in the air, cyanide contamination of water sources in the vast adjacent areas. The population adjacent to the gold mining areas businesses experiencing the impact of persistent cyanide in small and medium doses, and can be disastrous accidents in the tailings and slurry pipelines, especially during earthquakes .. Isolation of a large number of cyanide in the form of hydrocyanic acid and aerosols in the air in densely populated areas of the world beginning to alarm the public and professionals.
At present time develops the new direction in industry for extraction of gold from water solutions by different biomass of microorganisms, as alternative a technology “coal in pulp” (CIP), «carbon leaching» (CIL), coal in a solution " (CIS).
The need to address the environmental aspects of these problems is not only a scientific issue, but also social. One of the options for the processing of data is a combination of ore enrichment processes and biotechnology to tap the gold after the bacterial treatment of sulfide concentrates. In connection with this very relevant is the development of bio- and - nano sorption technology. This technology consists of three main processes:
- Bio dissection of mineral objects;
- Selective adsorption of metals on biological and nanosorbents;
- Bio-and nanosorptional flotation.
Influence of the offered project on progress in the given area. In result of the experiments will be opened gold, which is a naturally occurring nanomaterials with unique properties. Nano-dimensional particles of gold will be received after colloid flotation of biomass saturated with metal, and its destruction, by passing the cyanidation process. Toxic metals from waste water will be removed by nanosorbents. New technologies, which would reduce or eliminate the use of toxic chemicals in the water and cross-border areas (Lake Iskander- Kul and Zarafshan River Basin) of country, will be developed.
Competence of the project participants in this area. The project will be carried out at the Institute of Chemistry of the Academy of Sciences of the Republic of Tajikistan, where for many years researches are conducting in the field of flotation, hydrometallurgy, biotechnology, as evidenced by numerous publications and presentations at international conferences (The list of some publications is given in Supporting Information). 4 professors and 4 candidates of science (PhD on science) are among the project participants. They have extensive experience in the enrichment of ores of antimony, gold, copper, bismuth, lead, etc., and in terms of concentrates preparation by hydrometallurgical methods.
Expected Results and Their Application. In result of performance of the project will be developed technologies for arsenic-bearing gold ores processing of arsenic-bearing gold ores of the Republic of Tajikistan deposits which would reduce or eliminate the use of toxic chemicals in the water and cross-border areas (Lake Iskander- Kul and Zarafshan River Basin) of country.
The technology of bacterial leaching of persistent gold- sulfide concentrates with using of microorganisms consortium with a further allocation of submicroscopic gold by colloidal flotation of biomass and its destruction will be developed. In result the gold as natural nanoparticles will be received. Solutions containing arsenic after bacterial oxidation of flotation concentrate will be utilized with using nanosorbents based on iron. The developed ecologically pure technology can be used in industrial preparation of persistent gold ores of Tajikistan and of other countries similar ores.
Meeting ISTC Goals and Objectives. The project employed professionals (47 %) that were previously occupied by the so-called weapons technology in the performance of government programs of the USSR, and who will participate in the project. Professors Zinchenko Z. and Solozhenkin P. and scientists Ismailova M,and Tuymin I, took part in the project of ISTC N1598. Experience of specialists work in weapons technology is in area 2, 3, 5 according to Appendix 2.The project itself has only peaceful purposes, and is consistent with the objectives of the ISTC.
During of the project execution will be established new and restored old contacts with leading research centers involved in bio-and nanotechnology. In addition, studies will be presented at international conferences and symposia. This will facilitate the involvement of scientists in Tajikistan into the global scientific community.
Data on the volume of work. The project will perform the following milestones:
- Implementation of the mineralogical and chemical study of gold-containing ores of Tajikistan (Deposits Chore or Duoba,).
- Separation of microorganisms from the goldcontaining ores, tailing ponds. The study of the conditions for obtaining micro-organisms from a variety of hot hydrogen sulfide sources in Tajikistan.
- Development of flowsheets mineral processing of ores with a maximum recovery of useful components in concentrates.
- Identify the basic parameters of the biological interaction of bacteria with minerals of ores and ore.
- Biotechnology of deposit Chore or Duoba ore.
- Study of the sorption of gold by biomass, the development of the methods of the estimation of the fullness of the saturation of the biomass microorganism under bacterial processing concentrates, containing gold and accompanying elements.
- Flotation of the biomass, loaded with gold, and getting gold in the form of natural nano-particles.
- Investigation of nanosorbents to remove toxic metals from waste water.
- Presentation of the results to the international scientific community.
The Role of Foreign Collaborators. Foreign collaborators are the important part for successful performance of the planned projects both estimation of fundamental and practical meaning of quality of performance of job and its results. A scientific - practical direction spent by them are rather close on character and meaning of the developed project. Within the framework of the uniform project and course of its performance it is obviously possible mutual information interchange, granting of the comments to the technical reports, sharing of the scientific equipment, rendering of assistance and granting of material support by the participant of the projects in visiting the international meetings, realization of joint working seminars.
Technical Approach and Methodology. In studying the chemical composition of ores and concentrates are used various physic-chemical methods, such as assay, atomic absorption, mass spectrometry and atomic emission, optical and electron microscopy, etc. In the process of work bacterial strains are selected from local mineral resources - of gold ores, and mineral hot sources in Tajikistan.. For the first time will be studied biotechnology in the preparation of arsenic-bearing gold ores of Chore deposit for the oxidation of sulfides and release of gold. To extract the gold physical and -chemical parameters of the process of "biomass of microorganisms in the pulp" will be investigated. Nanosorbents will be used for utilization of arsenic-containing solutions.


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