Investigation of Pulsed Electromagnetic Action on Physical-Chemical Characteristics of Polydisperse Minerals
The goal of the project is to investigate the influence of pulsed high power electromagnetic radiation on the physical and chemical properties of natural media. The main attention will be paid to the processes accompanying disintegration of the natural mixture of dielectrics, semiconductors and metals that form minerals, as a result of the modification of their electric, physical, chemical and mechanical properties under the action of high power electromagnetic pulses. Physical and chemical modifications of polydispersional mineral medium under the action of powerful pulses of high frequency radiation will also be investigated by modern methods of X-rays structural and phase analysis, chemical and morphological analysis.
The completely new method of high power electromagnetic pulses application suggested by the project participants from IRE RAS and ICEMR RAS takes a distinctive place among the known nontraditional methods of the energetic disintegration of the mineral raw materials, such as the electrochemical oxidation, the microwave heating, the irradiation by accelerated electrons, etc. Preliminary investigations performed in the above institutions in this domain revealed the possibility of the efficient disintegrating action of the powerful electromagnetic pulses on the mineral media. One can now make the following conclusions based on the aforementioned experiments:
1. The increase in gold extraction by 1.5-2 times is possible to achieve after the irradiation of difficult concentration gold-containing ores as compared with the usual methods.
2. Under the flotation scheme of the process of metal extraction from the ores, the size of particles does not significantly influence the result. In the experiments performed, the best results were obtained with the relatively large particles (up to 1 mm).
3. The investigations carried out with the waste products (tailings) of the ore mining and processing enterprises showed that the noble metal extraction after the powerful pulse irradiation increases by 5-10 times from 10% (on average) up to 50-80% depending on the type of tailing.
However, the gist of numerous accompanying physical and chemical phenomena is still unclear because of the tremendous complexity of the processes in the natural media. In the framework of this project, the bulk of attention will be paid to the processes in which the disintegration of a natural mixture of dielectrics, semiconductors and metals constituting a mineral occur. The considered disintegration takes place in the course of modification of electrical, physical, chemical and mechanical properties of the mineral medium under the action of power electromagnetic pulses. The kinetics of breakdown will be also studied, as well as the change of morphology, phase and granulometric composition of mineral complexes under the action of this breakdown.
The main goal of the project is to investigate the mechanism of action of powerful electromagnetic pulses on polydispersional mineral media. The following program is suggested:
1. To develop a physical model of modification of mineral media under the action of powerful electromagnetic pulses on the basis of existent experimental data and those obtained as a result of the future experiments in the framework of the project.
2. To elaborate and construct a complex of electrophysical equipment ensuring powerful video pulses with the electric field intensity on the sample up to 300 kV/cm and the pulse front duration up to 5 ns. This complex must provide the operation in the pulsed mode with the repetition frequency up to 50 Hz.
3. To elaborate and construct the powerful microwave radiation generators which provide pulses of nanosecond duration. The generator design is based on the high-current electron accelerator with explosive emission. These generators must provide microwave pulses with the pulse width of about 5 ns, output power up to 30 MW and repetition frequency up to 10 Hz.
4. Using known physical and chemical methods, to investigate the composition and properties of polydispersional mineral media before and after the attack.
5. To perform the investigation of the effect of the powerful electromagnetic pulses on the surface modification of minerals and on the processes of mineral medium disintegration.
6. To perform the investigation of the influence of the powerful electromagnetic pulses on the effectiveness of noble metal extraction from the difficult concentration sulphide ores and from the tailings of the ore mining and processing enterprises.
In particular, theoretical and experimental studies include:
-the development a physical model for the breakdown of a polydispersional mineral medium under powerful electromagnetic pulses application. The model should predict and substantiate the optimal granular size of the materials to be treated;
-theoretical analysis and experimental substantiation of the optimal parameters for the pulse effect on mineral complexes;
-investigation of defects structure and surface condition for minerals like pyrite, arsenopyrite, etc;
-investigation of phase composition of metalliferous sulphides before and after the treatment by powerful electromagnetic pulses;
-studying of the physical properties of the natural media including the X–rays structure analysis, optical microscopy and scanning electron microscopy.
The participants of the project are skilled enough for its realization. Particularly, preliminary studies of powerful electromagnetic pulses influence on auriferous ores and products of their technological processing were performed in IRE RAS and ICEMR RAS. The intensive work over the generation of the powerful electromagnetic pulses with the required parameters has been in progress in IEP UrD RAS for a long time already. It must be mentioned that the equipment used in the preliminary experiments and stocked at present in the Institutes does not allow one to carry out the full complex of investigations planned in the project even after its modernization. This is the reason of the necessity to develop new powerful pulse generators with the required parameters.
Most of the scientists who intends to take part in the project were engaged in the development of superpower sources of electromagnetic radiation, which are used nowadays only for the military purposes. Their qualification in this domain is doubtless what is proved by their numerous publications in Russian and foreign scientific literature. The conversion of the research work of the personnel is in line with the aims of ISTC. The development of new civil areas of powerful electromagnetic pulses applications stipulates the spread of the accumulated experience abroad.
The following foreign collaborators are suggested:
Institute of Plasma Physics at Maryland University (USA) and Department of Chemistry of Cambridge University (Great Britain). In the course of the project accomplishment, a wide exchange of scientific information and joint scientific actions are intended.
The basic technical approaches to the problems posed in the project are associated with the previous activity of the participants. It includes the construction of equipment complexes for the powerful electromagnetic pulses action on polydispersional mineral materials, as well as development of theoretical models and experimental studies of treated materials. The proposed method allows to analyze physical and chemical processes accompanying powerful electromagnetic pulses application and to study the emerged mineral media modifications. A peculiar feature of the methodology is the combined use of physical and chemical methods together with methods usually used in geology and geochemistry.
The accomplishment of the entire complex of the project investigations will provide the basis of the principally new technology for the processing of the ores containing rare and noble metals. In addition to the effect of high degree of the metal extraction, the elaborated technology will possess some other advantages. One can foremost mention the technology resources-economy due to the possibility to exclude some technological stages (the comminuting and breakage) in the process of the ore preparation. In addition, the technology is an energy-saving due to the fact that the powerful electromagnetic pulse action is selective and effects mainly the most weak spots (the local inclusions, crystal bounds and defects, etc.) thus promoting the noble metals’ disclosure. Moreover, this technology is ecologically clean because the used electromagnetic pulses practically do not influence the human and the environment.
The application of this technique and technology to the processing of the ore mining enterprises’ tailings will allow one to perform the secondary processing of the tremendous amount of waste products’ reserves by additional extracting the rare and noble metals out of them. Along with the economic effect, the application of the elaborated technology based on the method proposed in the project will result in the considerable improvement of the ecological situation in the ore mining and processing industry regions.